A printing unit of a flexographic printing press

Abstract

The utility model relates to the field of flexographic printing machine especially, a kind of printing unit of flexographic printing machine.It includes mounting bracket and edition roller and impression roller rotationally arranged on mounting bracket, the edition roller is used to transfer text to the printing material, the impression roller is located below edition roller and is used to support printing material, edition roller and impression roller between the edition roller and impression roller form the impression gap for printing material to pass through, edition roller seat is rotationally arranged on the mounting bracket, edition roller seat includes transmission part and connecting portion, sliding block is rotationally connected on the transmission part, the connecting portion is rotatably connected with edition roller, further include compression assembly, the compression assembly is used to drive edition roller seat rotation, to edition roller and impression roller compression, the compression assembly includes compression drive motor and compression lead screw, the compression drive motor is used to drive compression lead screw rotation, the sliding block is screw-threaded connection on compression lead screw.

Description

Technical Field

[0001] This utility model relates to the field of flexographic printing machines, and in particular to a printing unit of a flexographic printing machine. Background Technology

[0002] A flexographic printing press is a letterpress printing device that uses flexible printing plates. Ink is transferred from the printing plate to the substrate via an anilox roller. A typical flexographic printing press consists of an unloading unit, a tension control unit, a traction feeding unit, a printing unit, a drying unit, and a rewinding unit. The basic printing process is as follows: the substrate is released from the unloading unit, passes through tension control and traction feeding, and then enters the printing unit. Each color group is printed sequentially, and after drying, it is rewound by the rewinding unit.

[0003] In flexographic printing presses, the printing unit includes a rotating printing roller and a plate roller, as well as a clamping mechanism. The clamping mechanism is one of the core components ensuring print quality. It is used to press the printing roller and the plate roller together, keeping the substrate stable at the printing contact surface and preventing slippage of the substrate from affecting registration accuracy and print quality. Most existing flexographic printing presses use cylinders as the drive source for their clamping mechanisms. The cylinders push the pressure roller or a rocker arm to achieve the pressing and separation between the printing roller and the plate roller.

[0004] However, using cylinders as the drive source for the clamping mechanism has many shortcomings in practical applications. The working pressure of the cylinder depends on the external air supply. When the air supply pressure fluctuates, the cylinder output force changes accordingly, resulting in uneven clamping force and affecting the registration accuracy. In addition, there is a delay in cylinder action, and it is difficult to ensure perfect synchronization when multiple cylinders work together. Furthermore, after long-term use, the cylinders are in a state of fatigue, and the output accuracy and support stability gradually decrease. The attenuation of clamping force is difficult to compensate for by simple means. Utility Model Content

[0005] To address the aforementioned problems, this invention provides a printing unit for a flexographic printing machine, aiming to offer a driving solution with stable pressure and adjustable output force.

[0006] The present invention provides a printing unit for a flexographic printing machine, which adopts the following technical solution: A printing unit of a flexographic printing machine includes a mounting frame and a plate roller and a substrate roller rotatably mounted on the mounting frame. The plate roller is used to transfer images onto a substrate, and the substrate roller is located below the plate roller and used to support the substrate. An impression gap is formed between the plate roller and the substrate roller for the substrate to pass through. A plate roller seat is rotatably mounted on the mounting frame. The plate roller seat includes a transmission part and a connecting part. A slider is rotatably connected to the transmission part. The connecting part is rotatably connected to the plate roller. The unit also includes a clamping assembly for driving the plate roller seat to rotate to clamp the plate roller and the substrate roller together. The clamping assembly includes a clamping drive motor and a clamping screw. The clamping drive motor drives the clamping screw to rotate, and the slider is threadedly connected to the clamping screw.

[0007] By adopting the above technical solution, the clamping drive motor drives the lead screw to rotate. Through the threaded engagement between the lead screw and the slider, the rotational motion is converted into the linear motion of the slider. The slider drives the printing roller seat to swing around its rotation axis through the transmission part. The connecting part drives the printing roller to swing closer to the printing roller, thus achieving clamping. The motor drive does not rely on an external air source, the output torque is stable and unaffected by air source pressure fluctuations, and the clamping force remains constant. The lead screw drive has a self-locking characteristic, and the printing roller seat can remain in the current position after the motor stops rotating, maintaining the clamping force between the printing roller and the printing roller without continuous power supply. At the same time, the motor has a fast response speed, without the delay problem of cylinder action, and maintains good output accuracy after long-term use. The attenuation of clamping force can be precisely compensated through motor control.

[0008] Optionally, the printing roller holder includes a transmission plate and a connecting plate connected together, with an included angle between the transmission plate and the connecting plate. The transmission part and the connecting part are respectively located at the two ends of the transmission plate and the connecting plate, and the rotation shaft of the printing roller holder is located at the connection between the transmission plate and the connecting plate.

[0009] By adopting the above technical solution, the printing roller seat is bent as a whole, with the transmission plate extending obliquely downward and the connecting plate extending obliquely upward, so that the rotation axis of the printing roller seat is located at the intersection of the two. This bent structure ensures sufficient lever arm length while allowing the clamping assembly to be arranged obliquely below the printing roller rather than directly below or to the side, making full use of the space at the bottom of the equipment, avoiding interference with other components, and also facilitating the compact layout of the overall clamping assembly.

[0010] Optionally, a locking component is also included for locking the printing roller holder onto the mounting bracket.

[0011] By adopting the above technical solution, once the printing roller seat has swung into position and the clamping force between the printing roller and the substrate roller reaches the set value, the locking component locks the printing roller seat and the mounting frame together, preventing any relative movement between them. In this way, the locking component takes on the task of maintaining the position of the printing roller seat, and the clamping drive motor can stop working and be de-energized after locking, eliminating the need for continuous power to maintain torque, thus reducing energy consumption and motor heat generation. Furthermore, the locked mechanical connection is more reliable than a self-locking motor and can better resist vibrations and impacts generated during the printing process.

[0012] Optionally, the locking assembly includes a locking cylinder, a swing arm, a locking block, and a locking groove. The locking cylinder is mounted on the printing roller seat, and the piston rod of the locking cylinder is eccentrically rotatably connected to the swing arm. The swing arm is rotatably connected to the printing roller seat, and the locking block is fixedly connected to the swing arm. The locking groove is formed on the mounting bracket and extends along the movement path of the transmission part. The locking block slides in the locking groove, and the locking cylinder is used to drive the swing arm to rotate until the locking block abuts against the groove wall of the locking groove.

[0013] By adopting the above technical solution, when the printing roller seat rotates, the locking block slides within the locking groove along with the printing roller seat. After the printing roller seat is in position, the locking cylinder pushes the swing arm to swing, and the locking block deflects under the action of the swing arm, causing its side to come into close contact with the groove wall of the locking groove. The friction force locks the printing roller seat onto the mounting frame. The locking groove extends along the movement path of the transmission unit, ensuring that the locking block can contact the groove wall to lock regardless of its position in the stroke. This allows the printing roller seat to be locked at any position, achieving a stepless locking function.

[0014] Optionally, it also includes an anilox roller rotatably mounted on a mounting frame, the anilox roller being located above the printing roller and used to transfer ink to the printing roller, an anilox roller seat being rotatably connected to the anilox roller, the anilox roller seat being slidably mounted on the mounting frame, and a pressing assembly for driving the anilox roller seat to slide so as to press the anilox roller and the printing roller together.

[0015] By adopting the above technical solution, the contact pressure between the anilox roller and the printing roller directly affects the uniformity of ink transfer and printing quality. By using an independent pressing component to precisely control the contact pressure, the anilox roller and the printing roller can always maintain a stable pressing force, ensuring the uniformity and stability of ink transfer.

[0016] Optionally, the pressing assembly includes a pressing drive motor and a pressing screw. The pressing drive motor is used to drive the pressing screw to rotate. The anilox roller seat is threadedly connected to the pressing screw. It also includes a guide structure, which is used to guide the sliding of the anilox roller seat.

[0017] By adopting the above technical solution, the same motor + screw drive scheme is used as the pressing component, so that the pressing force between the anilox roller and the printing roller also has the advantages of stable pressure, accurate output, and no dependence on air source. Moreover, the control logic is consistent with that of the pressing component, which facilitates the unified control of the whole machine.

[0018] Optionally, the pressing assembly further includes pulleys and a timing belt. There are at least two pulleys. The pressing drive motor is used to drive one of the pulleys to rotate. One of the pulleys is coaxially arranged and fixedly connected to the pressing screw. The timing belt is wound around the pulley.

[0019] By adopting the above technical solution, when the installation position of the pressing drive motor and the shaft end position of the lead screw cannot be directly coaxially connected due to space limitations, the power can be transmitted over long distances through pulleys and synchronous belts. This allows the motor to be placed in any suitable position on the mounting frame, avoiding the impact of motor size limitations on the overall layout and improving the flexibility of equipment layout.

[0020] Optionally, the guiding structure includes a guide block and a guide rail. The guide block is connected to the anilox roller seat, and a guide groove is provided on the guide block for the guide rail to pass through. The guide rail is mounted on the mounting frame.

[0021] By adopting the above technical solution, the sliding fit between the guide block and the guide rail precisely guides the movement of the anilox roller seat, ensuring that the anilox roller seat always moves in a straight line, and ensuring that the anilox roller always remains axially parallel to the printing roller during the pressing process, so that the ink transfer thickness in the width direction of the printing roller is uniform.

[0022] Optionally, a locking assembly is also included, which is used to lock the anilox roller seat onto the mounting frame. The structure of the locking assembly is the same as that of the locking assembly.

[0023] By adopting the above technical solution, the anilox roller seat also needs to be locked after pressing to maintain the clamping force between the anilox roller and the printing roller, and to prevent the pressing drive motor from being continuously energized. Using the same structure as the locking component ensures that the locking function on the anilox roller side is structurally consistent with the locking function on the printing roller side, simplifying the types of parts, reducing manufacturing costs, and unifying the locking control logic on both sides, thus facilitating equipment debugging and maintenance. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of this utility model.

[0025] Figure 2 This is a schematic diagram of the locking component in this utility model.

[0026] Figure 3 This is another structural schematic diagram of the present invention.

[0027] Figure 4 yes Figure 3 Enlarged view of point A in the middle.

[0028] Explanation of reference numerals in the attached drawings: 1. Mounting frame; 2. Printing roller; 3. Printing roller; 4. Printing roller seat; 41. Transmission unit; 42. Connecting unit; 43. Transmission plate; 44. Connecting plate; 5. Slider; 6. Pressing assembly; 61. Pressing drive motor; 62. Pressing screw; 7. Locking assembly; 71. Locking cylinder; 72. Swing arm; 73. Locking block; 74. Locking groove; 8. Anilox roller; 9. Anilox roller seat; 100. Pressing assembly; 110. Pressing drive motor; 120. Pressing screw; 130. Pulley; 140. Synchronous belt; 200. Guide structure; 210. Guide block; 220. Guide rail; 300. Locking assembly. Detailed Implementation

[0029] The following combination Figures 1-4 The present invention will be described in further detail below.

[0030] This utility model discloses a printing unit of a flexographic printing machine. (Refer to...) Figure 1 The printing unit of the flexographic printing press includes a mounting frame 1 and a plate roller 2 and a substrate roller 3 rotatably mounted on the mounting frame 1. The plate roller 2 is used to transfer images onto the substrate. The substrate roller 3 is located below the plate roller 2 and is used to support the substrate. An impression gap is formed between the plate roller 2 and the substrate roller 3 for the substrate to pass through. A plate roller seat 4 is rotatably mounted on the mounting frame 1. The plate roller seat 4 includes a drive part 41 and a connecting part 42. A slider 5 is rotatably connected to the drive part 41, and the connecting part 42 is rotatably connected to the plate roller 2. The printing unit also includes a clamping assembly 6. The clamping assembly 6 is used to drive the plate roller seat 4 to rotate, so that the plate roller 2 rotates towards the substrate roller 3, pressing the plate roller 2 and the substrate roller 3 together. There are two sets of clamping assemblies 6, located on both sides of the axial direction of the plate roller 2.

[0031] Reference Figure 1 The mounting frame 1 can be made of cast iron or welded steel plate, possessing sufficient rigidity and vibration resistance. The printing roller 2 is a cylindrical roller body covered with a flexible printing plate, and can be made of aluminum alloy or steel core. The printing roller 3 is a support roller, which can be made of steel roller body, and its surface can be covered with a rubber layer to increase the friction between it and the substrate. The printing roller seat 4 can be made of cast iron or steel and is rotatably connected to the printing roller 2 via bearings. The pressure drive motor 61 is preferably a stepper motor or servo motor, which can achieve precise angle control.

[0032] Reference Figure 1The printing roller holder 4 includes a transmission plate 43 and a connecting plate 44 connected together. An angle exists between the transmission plate 43 and the connecting plate 44. The transmission part 41 and the connecting part 42 are located at opposite ends of the transmission plate 43 and the connecting plate 44, respectively. The rotation axis of the printing roller holder 4 is located at the connection point between the transmission plate 43 and the connecting plate 44. The included angle between the transmission plate 43 and the connecting plate 44 is preferably 90° to 150°. The transmission plate 43 extends obliquely downwards, and the connecting plate 44 extends obliquely upwards, allowing the pressing assembly 6 to be arranged obliquely below the printing roller 2 rather than directly below or to the side. In other embodiments, the included angle between the transmission plate 43 and the connecting plate 44 can also be adjusted according to the equipment space layout.

[0033] Reference Figure 1 The clamping assembly 6 includes a clamping drive motor 61 and a clamping screw 62. The clamping drive motor 61 drives the clamping screw 62 to rotate, and the slider 5 is threadedly connected to the clamping screw 62. The clamping drive motor 61 is preferably a stepper motor or a servo motor, which can achieve precise angle control. The clamping screw 62 can be a trapezoidal screw or a ball screw; in this embodiment, a ball screw is preferred. In other embodiments, the clamping drive motor 61 can also be a DC motor with an encoder, and the clamping screw 62 can also be a common sliding screw.

[0034] Reference Figure 1 and Figure 2 The printing unit also includes a locking assembly 7. The locking assembly 7 is used to lock the printing roller seat 4 onto the mounting frame 1. The locking assembly 7 includes a locking cylinder 71, a swing arm 72, a locking block 73, and a locking groove 74. The cylinder seat of the locking cylinder 71 is fixedly connected to the printing roller seat 4, and the piston rod of the locking cylinder 71 is eccentrically rotatably connected to the swing arm 72. The swing arm 72 is rotatably connected to the printing roller seat 4, and the locking block 73 is fixedly connected to the swing arm 72. The locking groove 74 is formed on the mounting frame 1 and extends along the movement path of the transmission part 41. The locking block 73 slides in the locking groove 74. The locking cylinder 71 drives the swing arm 72 to rotate until the locking block 73 abuts against the groove wall of the locking groove 74.

[0035] Reference Figure 1 and Figure 2 The locking cylinder 71 can be a single-acting or double-acting cylinder. Its piston rod end is rotatably connected to the rocker arm 72 via a pin, and there is an eccentricity between the connection point and the rotation center of the rocker arm 72. When the piston rod of the locking cylinder 71 extends or retracts, the rocker arm 72 swings around its rotation axis, and the locking block 73 deflects accordingly. The side of the locking block 73 abuts tightly against the groove wall of the locking groove 74, generating friction and locking the printing roller seat 4 onto the mounting frame 1. The width of the locking groove 74 is slightly larger than the thickness of the locking block 73. In other embodiments, the locking cylinder 71 can also be replaced by an electric push rod.

[0036] In other embodiments, the locking component 7 may also employ an electromagnetic lock, a pin-type locking structure, a friction plate-type locking structure, a clamping-type locking structure, or a ratchet-pawl-type locking structure, etc.

[0037] Reference Figure 3 The printing unit also includes an anilox roller 8 rotatably mounted on a mounting frame 1. The anilox roller 8 is located above the printing plate 2 and is used to transfer ink onto the printing plate 2. An anilox roller seat 9 is rotatably connected to the anilox roller 8 and is slidably mounted on the mounting frame 1. The printing unit also includes a pressing assembly 100. The pressing assembly 100 is used to drive the anilox roller seat 9 to slide, causing the anilox roller 8 to slide closer to the printing plate 2, pressing the anilox roller 8 against the printing plate 2. The anilox roller 8 is a metal roller body. The anilox roller seat 9 can be made of cast iron or steel and is rotatably connected to the anilox roller 8 via bearings.

[0038] Reference Figure 3 and Figure 4 The pressing assembly 100 includes a pressing drive motor 110 and a pressing screw 120. The pressing drive motor 110 is used to drive the pressing screw 120 to rotate, and the anilox roller seat 9 is threadedly connected to the pressing screw 120.

[0039] Reference Figure 4 The printing unit also includes a guide structure 200, which guides the sliding of the anilox roller holder 9. The guide structure 200 includes a guide block 210 and a guide rail 220. The guide block 210 is connected to the anilox roller holder 9, and a guide groove is formed on the guide block 210 for the guide rail 220 to pass through. The guide rail 220 is mounted on the mounting frame 1. The guide block 210 and the guide rail 220 are clearance-fitted. In other embodiments, the guide structure 200 may also employ a guide post and guide sleeve structure.

[0040] Reference Figure 4 The pressing assembly 100 also includes pulleys 130 and a timing belt 140. At least two pulleys 130 are provided. A pressing drive motor 110 drives one of the pulleys 130 to rotate. One pulley 130 is coaxially arranged and fixedly connected to the pressing screw 120. The timing belt 140 is wound around the pulley 130. In this embodiment, the two pulleys 130 are a large pulley and a small pulley, respectively. The pressing drive motor 110 drives the small pulley to rotate, and the small pulley drives the large pulley to rotate via the timing belt 140. The large pulley is fixedly connected to the pressing screw 120, thereby achieving speed reduction and torque increase. In other embodiments, the pressing drive motor 110 can be coaxially arranged with the pressing screw 120. In this case, the pulleys 130 and the timing belt 140 can be omitted, and they can be directly connected via a coupling. In other embodiments, the pressing assembly 100 can also use a worm gear reducer to drive the pressing screw 120 to rotate.

[0041] In other embodiments, the pressing assembly 100 may also be driven by a hydraulic cylinder, a cam, a linkage mechanism, or a direct electric push rod, etc.

[0042] Reference Figure 4 The printing unit also includes a locking assembly 300. The locking assembly 300 is used to lock the anilox roller seat 9 onto the mounting frame 1. The structure of the locking assembly 300 is the same as that of the locking assembly 7. The locking assembly 300 also includes a locking cylinder 71, a swing arm 72, a locking block 73, and a locking groove 74. Its working principle is the same as that of the locking assembly 7, and will not be described again here. In other embodiments, the locking assembly 300 may also employ an electromagnetic lock or a mechanical pin structure for locking.

[0043] The implementation principle of the printing unit of the flexographic printing machine of this utility model is as follows: When it is necessary to press the plate roller 2 and the printing roller 3 together, the pressing drive motor 61 starts and drives the pressing screw 62 to rotate. The pressing screw 62 drives the slider 5, which is threaded to it, to move along the screw axis. The slider 5 pushes the plate roller seat 4 to swing around its rotation axis through the transmission part 41. The connecting part 42 of the plate roller seat 4 drives the plate roller 2 to swing closer to the printing roller 3, so that the printing gap between the plate roller 2 and the printing roller 3 is reduced until the required pressing force is reached. After the plate roller 2 is in place, the pressing drive motor 61 stops rotating. Due to the self-locking characteristic of the pressing screw 62, the slider 5 can be kept in the current position, and the position of the plate roller seat 4 is initially fixed. Then the locking component 7 is activated, the locking cylinder 71 drives the swing arm 72 to rotate, the locking block 73 deflects and closely abuts against the groove wall of the locking groove 74, and the plate roller seat 4 is locked on the mounting frame 1 by friction, and the pressing drive motor 61 can be de-energized. The pressing process between the anilox roller 8 and the printing roller 2 is similar. The pressing drive motor 110 drives the pressing screw 120 to rotate through the pulley 130 and the synchronous belt 140. The pressing screw 120 drives the anilox roller seat 9 to slide vertically upward along the guide structure 200, so that the anilox roller 8 approaches the printing roller 2 and achieves the required pressing force. After the anilox roller seat 9 is in place, the locking assembly 300 activates to lock the anilox roller seat 9 on the mounting frame 1, and the pressing drive motor 110 is de-energized.

[0044] The above are all preferred embodiments of this utility model, and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape and principle of this utility model should be covered within the scope of protection of this utility model.

Claims

1. A printing unit of a flexographic printing machine, characterized in that: The device includes a mounting frame (1) and a printing roller (2) and a printing roller (3) rotatably mounted on the mounting frame (1). The printing roller (2) is used to transfer images and text onto a substrate. The printing roller (3) is located below the printing roller (2) and is used to support the substrate. An impression gap is formed between the printing roller (2) and the printing roller (3) for the substrate to pass through. A printing roller seat (4) is rotatably mounted on the mounting frame (1). The printing roller seat (4) includes a transmission part (41) and a connecting part (42). (41) A slider (5) is rotatably connected to the upper part. The connecting part (42) is rotatably connected to the printing roller (2). It also includes a pressing assembly (6). The pressing assembly (6) is used to drive the printing roller seat (4) to rotate so as to press the printing roller (2) and the printing roller (3) together. The pressing assembly (6) includes a pressing drive motor (61) and a pressing screw (62). The pressing drive motor (61) is used to drive the pressing screw (62) to rotate. The slider (5) is threadedly connected to the pressing screw (62).

2. The printing unit of a flexographic printing machine according to claim 1, characterized in that: The printing roller holder (4) includes a transmission plate (43) and a connecting plate (44) connected to each other. There is an included angle between the transmission plate (43) and the connecting plate (44). The transmission part (41) and the connecting part (42) are respectively located at the two ends of the transmission plate (43) and the connecting plate (44). The rotation shaft of the printing roller holder (4) is located at the connection between the transmission plate (43) and the connecting plate (44).

3. The printing unit of a flexographic printing machine according to claim 1, characterized in that: It also includes a locking component (7) for locking the printing roller holder (4) onto the mounting bracket (1).

4. The printing unit of a flexographic printing machine according to claim 3, characterized in that: The locking assembly (7) includes a locking cylinder (71), a swing arm (72), a locking block (73), and a locking groove (74). The locking cylinder (71) is mounted on the printing roller seat (4). The piston rod of the locking cylinder (71) is eccentrically connected to the swing arm (72). The swing arm (72) is rotatably connected to the printing roller seat (4). The locking block (73) is fixedly connected to the swing arm (72). The locking groove (74) is opened on the mounting bracket (1). The locking groove (74) extends along the movement path of the transmission part (41). The locking block (73) slides in the locking groove (74). The locking cylinder (71) is used to drive the swing arm (72) to rotate until the locking block (73) abuts against the groove wall of the locking groove (74).

5. The printing unit of a flexographic printing machine according to claim 1, characterized in that: It also includes an anilox roller (8) rotatably mounted on a mounting frame (1), the anilox roller (8) being located above the printing roller (2) and used to transfer ink to the printing roller (2), an anilox roller seat (9) being rotatably connected to the anilox roller (8), the anilox roller seat (9) being slidably mounted on the mounting frame (1), and a pressing assembly (100) for driving the anilox roller seat (9) to slide so as to press the anilox roller (8) and the printing roller (2) together.

6. The printing unit of a flexographic printing machine according to claim 5, characterized in that: The pressing assembly (100) includes a pressing drive motor (110) and a pressing screw (120). The pressing drive motor (110) is used to drive the pressing screw (120) to rotate. The anilox roller seat (9) is threadedly connected to the pressing screw (120). It also includes a guide structure (200) for guiding the sliding of the anilox roller seat (9).

7. The printing unit of a flexographic printing machine according to claim 6, characterized in that: The pressing assembly (100) further includes a pulley (130) and a timing belt (140). There are at least two pulleys (130). The pressing drive motor (110) is used to drive one of the pulleys (130) to rotate. One of the pulleys (130) is coaxially arranged and fixedly connected to the pressing screw (120). The timing belt (140) is wound around the pulley (130).

8. The printing unit of a flexographic printing machine according to claim 6, characterized in that: The guide structure (200) includes a guide block (210) and a guide rail (220). The guide block (210) is connected to the anilox roller seat (9). The guide block (210) has a guide groove for the guide rail (220) to pass through. The guide rail (220) is mounted on the mounting frame (1).

9. A printing unit of a flexographic printing machine according to claim 3 or 4, characterized in that: It also includes a locking assembly (300) for locking the anilox roller seat (9) onto the mounting frame (1), and the structure of the locking assembly (300) is the same as that of the locking assembly (7).

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