Ink quantity control system of web press

Abstract

The invention discloses an ink quantity control system of a web press. The ink quantity control system comprises a main control unit, a network bridge and a motor driving unit. The main control unit comprises a PLC, a man-machine interaction assembly and a gateway communication interface. The network bridge comprises a gateway module, a network isolation module, a gateway communication interface and a CAN communication interface. The network bridge is connected with a gateway communication interface on the main control unit through a gateway bus; the motor driving unit comprises a plurality of motor driving plates; each motor driving board comprises four sets of motor driving circuits, a CAN communication interface and four motor control interfaces; outgoing lines of the four sets of motor driving circuits are connected with the four motor control interfaces in a one-to-one correspondence manner; the CAN communication interface on each motor driving board is connected with the CAN communication interface on the network bridge through a CAN bus; the four motor control interfaces on each motor driving board are connected with the four ink key motors in a one-to-one correspondence mode. According to the invention, the ink feeding amount of any area can be accurately adjusted.

Description

Technical Field

[0001] The invention relates to an ink quantity control system of a web printing press. Background Art

[0002] During the printing process, the printing press needs to flexibly adjust the amount of ink quickly and accurately according to the printing area. The thickness of the ink layer is not only restricted by the properties of the ink and paper, but also affected by printing speed, printing pressure, environmental factors, etc. (for example, different inks have different performance and coloring power. In order to achieve a certain required density value, the thickness of the ink layer is different). In short, in the actual production process, the control of the ink volume has very large uncertainty and strong nonlinearity due to the influence of various factors such as the printing machine type, paper, ink characteristics, water-ink balance, printing pressure, and measuring instruments. When the printing press is working, the ink volume requirements are different within the width range according to the requirements of the printed product, and it needs to be completed by adjusting the gap between the ink knife and the ink roller on the ink fountain. The existing ink knife is made of a whole continuous steel sheet, and the ink volume is controlled by the height of the top rod. However, when the ink knife adjusts the gap at a certain position, the continuity and elasticity of the steel sheet will interfere with the ink output at the adjacent position, resulting in unclear boundaries of the ink area. In addition, the steel sheet will fatigue and become wavy over time, making it impossible to correctly control the gap size, thus affecting the printing quality. This brings problems to occasions that require precise ink volume. The existing ink volume control system of web-fed printing presses has the following shortcomings:

[0003] 1. The analog potentiometer feedback has a high failure rate, low accuracy, and a large number of wiring harnesses are cumbersome to connect and difficult to maintain.

[0004] 2. The full circuit board control system is limited by high development and manufacturing costs and low compatibility. Summary of the invention

[0005] The object of the present invention is to overcome the defects of the prior art and provide an ink volume control system for a web printing press, which can ensure accurate control of the ink volume and enable multi-section regional ink knives and ink rollers to form a more uniform ink supply space.

[0006] The object of the present invention is achieved as follows: an ink volume control system of a web printing press, used for controlling an ink knife installed in an ink fountain and an ink fountain roller to form a uniform ink supply space; the ink fountain comprises two ink fountain end plates, an ink fountain seat, an ink knife and a plurality of ink volume adjustment mechanisms; the outer side surfaces of the two ink fountain end plates are respectively mounted on the inner sides of two main wall plates of the printing press through ink fountain end shafts in a one-to-one correspondence; the ink fountain seat is straddled between the two ink fountain end plates, the top surface of the ink fountain seat is a downwardly inclined inclined surface, a rectangular upper notch is provided at the front end of the top surface of the ink fountain seat, and a rectangular lower notch is provided at the rear end of the bottom surface of the ink fountain seat; the ink knife is mounted on the top surface of the ink fountain seat, and the ink knife is divided into a plurality of regional ink knives by a plurality of transverse cutting lines from a whole ink knife; the plurality of ink volume adjustment mechanisms are mounted on the ink fountain seat in a one-to-one correspondence with the plurality of regional ink knives;

[0007] Each set of ink volume adjustment mechanism includes a top block hinge shaft, an ink knife top block, an ink key motor and a top rod; wherein,

[0008] The top block hinge shaft is connected between the two ink fountain end plates of the ink fountain and is located at the upper part of the upper notch of the ink fountain seat;

[0009] A hinge hole is provided on the upper side of the ink knife top block, so that the ink knife top block can be rotatably sleeved on the top block hinge shaft;

[0010] The ink key motor is installed in the lower notch of the ink fountain seat through a motor mounting bracket; the ink key motor includes a DC brushless motor, a reducer connected to the front end of the rotating shaft of the DC brushless motor, and a Hall encoder installed at the rear end of the rotating shaft of the DC brushless motor;

[0011] The push rod is connected to the rotating shaft of the ink key motor. The push rod is a screw rod and is installed in a threaded guide hole provided on the ink fountain seat. The front end of the push rod abuts against the rear end surface of the lower part of the ink knife top block, so that the top front end of the ink knife top block abuts against the bottom front end of the ink knife in the corresponding area.

[0012] The ink volume control system includes a main control unit, a PN_SWT bridge and a motor drive unit; wherein,

[0013] The main control unit includes a PLC, a human-computer interaction component and a Profinet communication interface; the human-computer interaction component includes a touch screen and a keypad;

[0014] The PN_SWT bridge includes a Profinet gateway module, a network isolation module, a Profinet communication interface and a CAN communication interface; the PN_CAN bridge is connected to the Profinet communication interface on the main control unit via the Profinet bus;

[0015] The motor drive unit includes several motor drive boards; each motor drive board includes several sets of motor drive circuits, a CAN communication interface and several motor control interfaces; the lead wires of several sets of motor drive circuits are connected to several motor control interfaces one by one; the CAN communication interface on each motor drive board is connected to the CAN communication interface on the PN_CAN bridge through the CAN bus; the several motor control interfaces on each motor drive board are connected to the lead wires of several ink key motors one by one;

[0016] The ink volume control system is controlled according to the following steps:

[0017] S1. The ink volume control system is initialized after power-on. After the initialization is completed, the communication handshake is confirmed with all motor drive boards. After the communication handshake is successful, the ink volume control system is operated;

[0018] S2. Determine whether the ink key motor is faulty. If so, control the ink key motor to stop rotating and wait for the fault to be cleared;

[0019] S3. After the ink key motor is fault-free, the ink key motor is allowed to rotate; determine whether the ink key motor is locked. If locked, it cannot be operated;

[0020] S4. If the ink key motor has no faults and is not locked, the position of the ink key motor is determined. If the actual position of the ink key motor is equal to the set position of the ink key motor, the ink key motor stops running;

[0021] S5. If the actual position of the ink key motor is less than the set position of the ink key motor, the ink key motor rotates forward; if the actual position of the ink key motor is less than the set position of the ink key motor, the ink key motor rotates reversely;

[0022] S6. After starting the ink key motor to rotate forward or reverse, record the rotation duration of the ink key motor; if the rotation of the ink key motor times out and the actual position of the ink key motor fails to reach the set position of the ink key motor, the ink volume control system will sound a jam alarm and return to step S2, and the ink key motor will stop rotating.

[0023] The above-mentioned ink volume control system of the web printing press, wherein the lead wires of each ink key motor include two motor power lines, one Hall encoder power line, one Hall encoder ground line and two Hall encoder power line signal lines; the motor control interface on the motor drive board is a six-pin slot.

[0024] The ink volume control system of the web printing press of the present invention has the following characteristics:

[0025] 1. The micro motor driver board with Hall feedback has the advantages of small size, low power consumption, high integration and good reliability. The motor driver board receives the input signal of PLC and outputs it to the ink key motor after processing, drives the ink knife to adjust the opening, and at the same time, monitors the position of the ink knife in real time through the Hall encoder to form a closed-loop control to ensure the precise control of the ink amount, so that the multi-section area ink knife and ink roller can form a more uniform ink supply space, reducing unnecessary waste. The modular design can meet the number of ink knives of various specifications.

[0026] 2. All motor drive boards are centrally controlled by the main PLC. As an important equipment for industrial automation, PLC has the advantages of flexible programming, high reliability and strong scalability. In addition, the main control unit communicates with the host computer through the communication interface, and can also realize functions such as remote monitoring and fault diagnosis.

[0027] 3. The Hall encoder has a firm structure and long service life. It can work stably in various harsh environments, ensuring the long-term stable operation of the electrical control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of an ink fountain targeted by the ink volume control system of a web printing press of the present invention;

[0029] Figure 2 yes Figure 1 AA view in the figure;

[0030] Figure 3 1 is a schematic diagram of the ink volume control system of the web printing press of the present invention.

[0031] Figure 4 It is a network topology diagram of the ink volume control system of the web printing press of the present invention;

[0032] Figure 5 The invention discloses a control flow chart of an ink volume control system of a web printing press. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings.

[0034] See also Figure 1 and Figure 2 The ink volume control system of the web printing press of the present invention is used to control the ink knife and the ink roller installed in the ink fountain to form a uniform ink supply space; the ink fountain includes two ink fountain end plates 1, an ink fountain seat 2, an ink knife 3 and twenty-two sets of ink volume adjustment mechanisms.

[0035] The two ink fountain end plates 1 are installed one by one on the inner side of two main wall panels (not shown in the figure) of the printing press. The outer side surfaces of the two ink fountain end plates 1 are each connected to an ink fountain end shaft 12 through a locking device 11. The two ink fountain end shafts 12 are installed one by one on the two main wall panels of the printing press.

[0036] The ink fountain holder 2 is connected between the two ink fountain end plates 1. The top surface of the ink fountain holder 2 is a downwardly inclined inclined surface. A rectangular upper notch is provided at the front end of the top surface of the ink fountain holder 2, and a rectangular lower notch is provided at the rear end of the bottom surface of the ink fountain holder 2. An ink knife mounting groove is provided in the middle of the top surface of the ink fountain holder 2, and two screw through holes penetrating the rear end wall of the ink knife mounting groove are provided on the rear end surface of the ink fountain holder 2.

[0037] The ink knife 3 is fixed on the top surface of an ink knife bottom plate 30. The ink knife bottom plate 31 is installed in the ink knife installation groove of the ink fountain seat 2. A bottom threaded blind hole is provided on the bottom front of the ink knife bottom plate 31. Two rear threaded blind holes corresponding to the two screw holes on the ink fountain seat 2 are provided on the rear end surface of the ink knife bottom plate 31. Two ink knife adjustment screws 32 are installed in the two screw holes on the ink fountain seat 2 and then screwed into the two rear threaded blind holes on the ink knife bottom plate 31 one by one. The ink fountain seat 2 has two rear threaded blind holes corresponding to the two screw holes on the ink knife bottom plate 31. The two bottom threaded blind holes on the ink cutter 3 correspond to the waist-shaped mounting holes one by one, and a fixing screw 33 is installed in each of the two waist-shaped mounting holes. The two fixing screws 33 are screwed into the two bottom threaded blind holes on the ink cutter bottom plate 31 one by one; by rotating the two ink cutter adjustment screws 32, the distance between the front end of the ink cutter 3 and the ink fountain roller 10 can be preliminarily adjusted. After the adjustment is completed, the ink cutter bottom plate 31 is fixed to the ink fountain seat 2 by the fixing screws 33; the ink cutter 3 is divided into twenty-two regional ink cutters 30 by a plurality of transverse cutting lines from a whole ink cutter.

[0038] Twenty-two sets of ink volume adjustment mechanisms are mounted on the ink fountain holder 2 in correspondence with the twenty-two sections of regional ink knives 30; each set of ink volume adjustment mechanisms comprises a top block hinge shaft 4, an ink knife top block 5, an ink key motor 6 and a top rod 7; wherein the top block hinge shaft 4 is connected between the two ink fountain end plates 1 of the ink fountain and is located at the upper part of the upper notch of the ink fountain holder 2; a hinge hole is provided at the upper part of the side surface of the ink knife top block 5 so that the ink knife top block 5 can be rotatably mounted on the top block hinge shaft 4; the ink key motor 6 is connected to the top block hinge shaft 4 through the motor mounting bracket 61 and the two connecting blocks 6 2 is installed in the lower notch of the ink fountain holder 2, the ink key motor 6 includes a DC brushless motor, a reducer connected to the front end of the rotating shaft of the DC brushless motor and a Hall encoder installed at the rear end of the rotating shaft of the DC brushless motor; the push rod 7 is connected to the rotating shaft of the ink key motor 6 through a coupling 70, the push rod 7 is a screw and is installed in a threaded guide hole opened on the ink fountain holder 2, and the front end of the push rod 7 is against the lower rear end surface of the ink knife top block 5, so that the top front end of the ink knife top block 5 is against the bottom front end of the ink knife 30 in the corresponding area.

[0039] When the ink key motor 6 rotates forward, it drives the push rod 7 to rotate, so that the push rod 7 pushes the ink knife top block 5 to rotate around the top block hinge shaft 4, so that the ink knife top block 5 will push the front end of the ink knife 30 in the corresponding section upward, so that the gap δ between the front end of the ink knife 3A in the corresponding section and the ink fountain roller 10 is the smallest, that is, the ink output of the ink fountain is the smallest. Conversely, when the ink key motor 6 rotates reversely, the ink knife top block 5 rotates around the top block hinge shaft 4 by its own weight, so that the gap δ between the front end of the ink knife 3A in the corresponding section and the ink fountain roller 10 becomes larger, that is, the ink output of the ink fountain becomes larger.

[0040] Please see again Figure 3 and Figure 4 The ink volume control system of the web printing press of the present invention includes a main control unit 100, a PN_CAN bridge 200 and a motor drive unit.

[0041] The main control unit 100 includes a PLC, a human-machine interaction component and a Profinet communication interface; the human-machine interaction component includes a touch screen and a keypad.

[0042] The PN_CAN bridge 200 includes a Profinet gateway module, a network isolation module, a Profinet communication interface and a CAN communication interface; the PN_CAN bridge 200 is connected to the Profinet communication interface on the main control unit 100 via a Profinet bus.

[0043] The motor drive unit includes six motor drive boards 300, each of which has a model of DRVDM_103.PCB and includes a motor drive circuit, a CAN communication interface and four motor control interfaces. The four sets of motor drive circuits are connected to the four motor control interfaces in a one-to-one correspondence; each motor control interface is a six-pin slot; the CAN communication interface of each motor drive board is connected to the CAN communication interface on the PN_CAN bridge through the CAN bus; the four motor control interfaces on the five motor drive boards 300 are connected to the lead wires of the four ink key motors 6 in a one-to-one correspondence; and the two motor control interfaces on another motor drive board 300 are connected to the lead wires of the two ink key motors 6 in a one-to-one correspondence; the lead wires of each ink key motor 6 include two motor power lines, one Hall encoder power line, one Hall encoder ground line and two Hall encoder signal lines.

[0044] The main control unit 100 is used to convert the operator's key commands into digital quantities and transmit them to the motor drive board 300. At the same time, it displays the current state of the ink key motor 6 in real time based on the data fed back by the motor drive board 300 to determine whether a fault occurs.

[0045] Since the motor drive board 300 uses the CAN communication protocol, and the main control unit 100 uses the standardized Profinet protocol commonly used in the printing auxiliary system software under the PLC, the PN_CAN bridge 200 is used to achieve intercommunication between the CAN protocol and the Profinet protocol. At the same time, the PN_CAN bridge 200 performs effective network segment isolation through the network isolation module, thereby improving the reliability and security of the system.

[0046] The motor drive board 300 drives the ink-type motor to operate accurately according to the control information received from the PLC, and transmits the motor status information to the PLC according to the current position signal of the ink-type motor 6. The protection circuit in the motor drive board 300 can prevent the damage to the control device caused by the overcurrent and other faults caused by the ink-type motor 6, and reduce unstable electrical interference and signal crosstalk.

[0047] The communication data between each motor drive board 300 and the PN_CAN bridge 200 includes: motor set position, motor actual position, alarm information, fault reset control, and motor locking control.

[0048] The six motor drive boards 300 first establish communication with the main control unit 100 through the PN_CAN bridge 200. When the PLC sends a control signal, the PN_CAN bridge 200 sends the received signal to the motor drive board 300 through the CAN bus. The motor drive board 300 receives the signal sent by the PLC and outputs it to the ink key motor 6 after processing, driving the corresponding area ink knife 30 to adjust the opening. At the same time, the status information of the corresponding ink key motor 6 is monitored in real time through the Hall encoder and fed back to the motor drive board 300. When the motor drive board 300 sends the status information of the ink key motor 6 to the PN_CAN bridge 200, the PN_CAN bridge 200 automatically sends the data to the PLC through the Profinet communication interface to form a closed-loop control.

[0049] The PLC performs adaptive calculations based on the motor's set position value and the current motor's actual position value to obtain the target position of the ink key motor 6; then the PLC drives the ink key motor 6 under the motor drive board through the motor drive board according to the target position of the ink key motor 6. For the convenience of control and operation, four ink key motors 6 are used as a unit, and the four ink key motors 6 can be freely combined and controlled by a motor drive board 300.

[0050] The ink volume control system of the web printing press of the present invention is controlled according to the following steps:

[0051] S1. After the ink volume control system is powered on, the ink volume control system is initialized. After the initialization is completed, a communication handshake confirmation is performed. After the communication handshake is successful, the ink volume control system is operated;

[0052] S2. Determine whether the ink key motor is faulty. If so, control the ink key motor to stop rotating and wait for the fault to be cleared;

[0053] S3. After the ink key motor is fault-free, the ink key motor is allowed to rotate; determine whether the ink key motor is locked. If locked, it cannot be operated;

[0054] S4. If the ink key motor has no faults and is not locked, the position of the ink key motor is determined. If the actual position of the ink key motor is equal to the set position of the ink key motor, the ink key motor stops running;

[0055] S5. If the actual position of the ink key motor is less than the set position of the ink key motor, the ink key motor rotates forward; if the actual position of the ink key motor is less than the set position of the ink key motor, the ink key motor rotates reversely;

[0056] S6. After starting the ink key motor to rotate forward or reverse, record the rotation duration of the ink key motor; if the rotation of the ink key motor times out and the actual position of the ink key motor fails to reach the set position of the ink key motor, the ink volume control system will sound a jam alarm and return to step S2, and the ink key motor will stop rotating.

[0057] Since the ink knife 3 of the web offset printing machine is composed of twenty-two sections of regional ink knives 30, each section of the regional ink knife 30 is provided with an independent ink amount adjustment mechanism, each motor drive board is connected to four sections of regional ink knives 30, and the four sections of regional ink knives 30 can be freely combined, and then the above-mentioned control method can be used to finely adjust the ink amount of the four sections of regional ink knives.

[0058] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the relevant technical field may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the scope of the present invention and should be defined by the claims.

Claims

1. An ink volume control system for a web printing press, used for controlling an ink knife installed in an ink fountain and an ink fountain roller to form a uniform ink supply space; the ink fountain comprises two ink fountain end plates, an ink fountain seat, an ink knife and a plurality of ink volume adjustment mechanisms; the outer side surfaces of the two ink fountain end plates are respectively mounted on the inner sides of two main wall panels of the printing press through ink fountain end shafts in a one-to-one correspondence; the ink fountain seat is straddled between the two ink fountain end plates, the top surface of the ink fountain seat is a downwardly inclined inclined surface, a rectangular upper notch is provided at the front end of the top surface of the ink fountain seat, and a rectangular lower notch is provided at the rear end of the bottom surface of the ink fountain seat; the ink knife is mounted on the top surface of the ink fountain seat, and the ink knife is divided into a plurality of regional ink knives by a plurality of transverse cutting lines from a whole ink knife; the plurality of ink volume adjustment mechanisms are mounted on the ink fountain seat in a one-to-one correspondence with the multi-regional ink knives; wherein, Each set of ink volume adjustment mechanism includes a top block hinge shaft, an ink knife top block, an ink key motor and a top rod; The top block hinge shaft is connected between the two ink fountain end plates of the ink fountain and is located at the upper part of the upper notch of the ink fountain seat; A hinge hole is provided on the upper side of the ink knife top block, so that the ink knife top block can be rotatably sleeved on the top block hinge shaft; The ink key motor is installed in the lower notch of the ink fountain seat through a motor mounting bracket; the ink key motor includes a DC brushless motor, a reducer connected to the front end of the rotating shaft of the DC brushless motor, and a Hall encoder installed at the rear end of the rotating shaft of the DC brushless motor; The push rod is connected to the rotating shaft of the ink key motor. The push rod is a screw rod and is installed in a threaded guide hole provided on the ink fountain seat. The front end of the push rod abuts against the rear end surface of the lower part of the ink knife top block, so that the top front end of the ink knife top block abuts against the bottom front end of the ink knife in the corresponding area. Characterized in that the ink volume control system includes a main control unit, a PN_SWT bridge and a motor drive unit; The main control unit includes a PLC, a human-computer interaction component and a Profinet communication interface; the human-computer interaction component includes a touch screen and a keypad; The PN_SWT bridge includes a Profinet gateway module, a network isolation module, a Profinet communication interface and a CAN communication interface; the PN_CAN bridge is connected to the Profinet communication interface on the main control unit via the Profinet bus; The motor drive unit includes several motor drive boards; each motor drive board includes several sets of motor drive circuits, a CAN communication interface and several motor control interfaces; the lead wires of several sets of motor drive circuits are connected to several motor control interfaces one by one; the CAN communication interface on each motor drive board is connected to the CAN communication interface on the PN_CAN bridge through the CAN bus; the several motor control interfaces on each motor drive board are connected to the lead wires of several ink key motors one by one; The ink volume control system is controlled according to the following steps: S1. The ink volume control system is initialized after power-on. After the initialization is completed, the communication handshake is confirmed with all motor drive boards. After the communication handshake is successful, the ink volume control system is operated; S2. Determine whether the ink key motor is faulty. If so, control the ink key motor to stop rotating and wait for the fault to be cleared; S3. After the ink key motor is fault-free, the ink key motor is allowed to rotate; determine whether the ink key motor is locked. If locked, it cannot be operated; S4. If the ink key motor has no faults and is not locked, the position of the ink key motor is determined. If the actual position of the ink key motor is equal to the set position of the ink key motor, the ink key motor stops running; S5. If the actual position of the ink key motor is less than the set position of the ink key motor, the ink key motor rotates forward; if the actual position of the ink key motor is less than the set position of the ink key motor, the ink key motor rotates reversely; S6. After starting the ink key motor to rotate forward or reverse, record the rotation duration of the ink key motor; if the rotation of the ink key motor times out and the actual position of the ink key motor fails to reach the set position of the ink key motor, the ink volume control system will sound a jam alarm and return to step S2, and the ink key motor will stop rotating.

2. The ink volume control system of a web printing press according to claim 1, characterized in that: The lead wires of each ink key motor include two motor power wires, one Hall encoder power wire, one Hall encoder ground wire and two signal wires of the Hall encoder power wires; the motor control interface on the motor drive board is a six-pin slot.

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