A printing apparatus for a packaging box intaglio printing process

Abstract

The application discloses a printing equipment for a packaging box intaglio printing process and relates to the field of printing equipment, which comprises a rack, a printing plate cylinder mounted on the rack and a flat back pressure roller group arranged at a position corresponding to a printing area of the printing plate cylinder on the rack; the flat back pressure roller group comprises a driving synchronous roller and a tension synchronous roller which are arranged in parallel, a rigid support component is connected in a peripheral meshing manner to the driving synchronous roller and the tension synchronous roller, a printing pad is closely attached to the periphery of the rigid support component, and the printing pad is provided with a flat printing back pressure surface formed by the rigid support of the rigid support component on the side close to the printing plate cylinder; the flat back pressure roller group on the rack is arranged opposite to the printing plate cylinder, the flat back pressure roller group is tensioned and driven by the driving synchronous roller and the tension synchronous roller to drive the rigid support component, the rigid support component is used for providing a stable base for the peripheral printing pad, and thus a flat printing back pressure surface is formed, and the flat printing back pressure surface is used for providing flat support for the printing plate cylinder.

Description

Technical Field

[0001] This application relates to the field of printing equipment, and in particular to printing equipment for gravure printing of packaging boxes. Background Technology

[0002] In the field of gravure printing for packaging boxes, common printing methods include "rotary-to-rotary" and "rotary-to-flat". In the rotary-to-rotary method, the printing plate cylinder and the back pressure cylinder roll against each other, which is suitable for high-speed continuous printing. However, when printing large-format solid patterns, the line contact characteristics can easily lead to problems such as uneven pressure and inconsistent ink depth. See Chinese Patent Publication No. CN209037182U for a gravure printing equipment for paper packaging boxes. The rotary-to-flat method uses a printing plate cylinder and a flat impression table. The substrate is stationary or moves intermittently, and the printing is completed by the reciprocating pressure of the cylinder. This method has uniform pressure and high printing quality, and is especially suitable for substrates such as thick cardboard and cardstock.

[0003] However, traditional rotary printing equipment has a low printing speed, generally not exceeding 30 meters per minute, due to the frequent start and stop of the printing substrate, which limits production efficiency. To address this, this application proposes a method that retains the advantage of uniform pressure of rotary printing by using a planar back pressure roller group to drive the continuous movement of the printing substrate, thereby achieving high-speed and stable printing and meeting the needs of industrial mass production. Utility Model Content

[0004] To improve the low efficiency of traditional rotary printing processes, this application provides a printing device for gravure printing of packaging boxes.

[0005] The printing equipment for gravure printing of packaging boxes provided in this application adopts the following technical solution: A printing equipment for gravure printing of packaging boxes includes a frame and a printing plate cylinder mounted on the frame, wherein a planar back pressure roller group is provided on the frame at a position corresponding to the printing area of ​​the printing plate cylinder. The planar back pressure roller assembly includes a parallel active synchronous roller and a tension synchronous roller. A rigid support component is meshed around the periphery of the active synchronous roller and the tension synchronous roller. An impression backing belt is tightly connected to the periphery of the rigid support component. The side of the impression backing belt closest to the printing plate cylinder is rigidly supported by the rigid support component to form a flat impression back pressure surface.

[0006] By adopting the above technical solution, the planar back pressure roller group on the frame is arranged opposite to the printing plate cylinder. The planar back pressure roller group is tensioned and driven by the active synchronous roller and the tension synchronous roller, and the rigid support component is then used to provide a stable base for the outer printing backing belt, thus forming a flat printing back pressure surface, providing planar support for the printing plate cylinder, thereby realizing a circular pressure flat structure for continuous paper feeding of the printing substrate, which improves the printing speed while ensuring uniform pressure.

[0007] Preferably, a support frame is connected between both ends of the active synchronizing roller and the tension synchronizing roller. The support frame is fixedly connected to the frame. The end of the active synchronizing roller is rotatably connected to the support frame. A transverse groove is provided below the support frame. A crossbar is telescopically connected in the transverse groove. The end of the tension synchronizing roller is rotatably connected to the end of the crossbar. A large spring is provided in the transverse groove and compressedly connected to the crossbar.

[0008] By adopting the above technical solution, the support frame is fixed on the machine frame and is used to support the active synchronous roller and the tension synchronous roller. The tension synchronous roller slides in the horizontal groove of the support frame through the crossbar at the end, and uses the elastic force of the large spring to continuously apply outward tension, thereby automatically tensioning and expanding the lower surface of the surrounding rigid support component.

[0009] Preferably, a vertical groove is provided above the support frame, a vertical rod is telescopically connected in the vertical groove, a small spring is provided in the vertical groove and compressedly connected to the vertical rod, and a support roller is rotatably connected between the top ends of the two vertical rods, the support roller being positioned above the inner ring of the rigid support component.

[0010] By adopting the above technical solution, a small spring elastically supports the vertical rod in the vertical groove above the support frame, so that the support roller at the top of the vertical rod always presses against the upper part of the inner ring of the rigid support component. This is used to constrain and support the upper half of the rigid support component's circuit. Together with the lower half of the rigid support component, which is opened by the active synchronous roller and the tension synchronous roller, the rigid support component's shape is stable and its movement is smooth.

[0011] Preferably, the rigid support component includes a plurality of parallel circular rods and a plurality of chain plates connected to the ends of adjacent circular rods. Both ends of each circular rod are coaxially provided with a cylinder, and both ends of the chain plates are rotatably connected to the cylinders at the ends of the circular rods.

[0012] By adopting the above technical solution, the rigid support component is composed of parallel round rods and chain plates connecting their ends. The cylinders at the ends of the round rods form a rotatable connection with the chain plates, so that the rigid support component can provide a continuous rigid support surface through the round rods and can also achieve flexible bending through the hinge of the chain plates at the round rods.

[0013] Preferably, one side of the horizontal groove is connected to a first limiting hole, a first bolt is slidably connected in the first limiting hole, one end of the first bolt is threadedly connected to the horizontal rod, and one side of the vertical groove is connected to a second limiting hole, a second bolt is provided in the second limiting hole, and the second bolt is threadedly connected to the vertical rod.

[0014] By adopting the above technical solution, the horizontal bar restricts its extension stroke through the sliding fit between the first bolt and the first limiting hole, and the vertical bar restricts its extension stroke through the fit between the second bolt and the second limiting hole. This is used to prevent the horizontal bar and the vertical bar from moving excessively and to provide mechanical limits, thereby ensuring the stability and safety of the working position of the tension synchronization roller and the support roller.

[0015] Preferably, a pressure-bearing block is provided in the inner ring of the rigid support component, the pressure-bearing block is fixedly connected to the frame, and the lower surface of the pressure-bearing block is in contact with a plurality of round rods in the rigid support component.

[0016] By adopting the above technical solution, the pressure block fixed on the frame is set in the inner ring of the rigid support component. The lower surface of the pressure block directly contacts several round rods that constitute the rigid support component, and the key section forming the printing back pressure surface provides additional rigid support from the back, effectively preventing the rigid support component from bending or deforming under the squeezing pressure of the printing plate cylinder.

[0017] Preferably, the inner wall of the embossing strip is provided with a plurality of third rod grooves that mesh with the outer walls of a plurality of round rods in the rigid support component.

[0018] By adopting the above technical solution, the third groove on the inner wall of the embossing tape meshes with the round rod on the rigid support component, ensuring that the embossing tape and the rigid support component move synchronously without slippage, and together form a flat embossing back pressure surface.

[0019] Preferably, the top of the printing plate cylinder is provided with a first arc-shaped spring sheet and a second arc-shaped spring sheet on the non-printing areas on both sides of the substrate. The first arc-shaped spring sheet and the second arc-shaped spring sheet are located below the printing back pressure surface of the planar back pressure roller group. The first arc-shaped spring sheet and the second arc-shaped spring sheet are fixedly connected to the frame.

[0020] By adopting the above technical solution, the first and second arc-shaped spring sheets, fixed on the frame, have upward-curving arcs and are located at the inlet and outlet ends of the printing backing surface, respectively. They provide elastic upward support to the cardboard substrate from below, ensuring that the cardboard substrate can be flatly attached to the printing backing belt above during entry and exit of the printing area, preventing warping. Since the first and second arc-shaped spring sheets are located in the non-printing areas on both sides of the substrate, they only act on the edge area of ​​the substrate, avoiding contact with the printed graphics in the center.

[0021] In summary, this application includes at least one of the following beneficial technical effects: 1. This application adopts a flat back pressure roller group, which replaces the curved surface of the traditional back pressure roller with its flat back pressure surface. This allows the entire printing area of ​​the paperboard substrate to obtain uniform and consistent printing force when it passes through the printing plate cylinder. It effectively solves the problem of uneven pressure caused by the contact between the circular and circular lines of the paperboard substrate, and effectively eliminates the resulting quality defects such as ghosting and uneven ink layer depth. At the same time, the continuous paper feeding overcomes the shortcomings of the low efficiency of the traditional intermittent circular pressing method, which is conducive to the high-quality printing of large-format solid patterns.

[0022] 2. The meshing connection between the rigid support component in this application and the active synchronous roller, tension synchronous roller, support roller, and printing backing belt constitutes a precise synchronous transmission system. This design ensures that the printing backing belt runs smoothly without slippage, thereby providing a reliable guarantee for the registration accuracy of the printing process. Attached Figure Description

[0023] Figure 1 This is an overall schematic diagram of this application; Figure 2 For this application Figure 1 Enlarged view of point A; Figure 3 This is a partial sectional view of this application; Figure 4 For this application Figure 3 Enlarged view of point B; Figure 5 This is a partial sectional view of the rigid support component of this application; Figure 6 This is a partial cross-sectional view of the embossing backing tape of this application.

[0024] Reference numerals: 1. Frame; 2. Printing cylinder; 3. First arc-shaped spring plate; 4. Second arc-shaped spring plate; 5. Flat back pressure roller assembly; 51. Active synchronizing roller; 511. First rod groove; 52. Support roller; 521. Second groove; 53. Imprinting backing belt; 531. Third groove; 54. Rigid support component; 541. Round rod; 542. Chain plate; 543. Cylindrical column; 55. Tension synchronization roller; 551. Fourth groove; 56. Support frame; 561. Horizontal groove; 562. Horizontal bar; 563. Large spring; 564. First bolt; 565. First limiting hole; 566. Vertical groove; 567. Second limiting hole; 568. Small spring; 569. Vertical bar; 570. Second bolt; 57. Pressure block. Detailed Implementation

[0025] The following is in conjunction with the appendix Figures 1-6 This application will be described in further detail.

[0026] This application discloses a printing equipment for gravure printing of packaging boxes.

[0027] Reference Figure 1 , Figure 3 A printing device for gravure printing of packaging boxes includes a frame 1 and a printing plate cylinder 2, both based on existing mature technologies. The printing plate cylinder 2 is rotatably connected to the frame 1. A flat back pressure roller group 5 is mounted on the frame 1, with the installation position of the flat back pressure roller group 5 corresponding to the imprinting area of ​​the printing plate cylinder 2. The frame 1 can adopt a conventional wall panel or frame structure, such as the rigid base commonly found in sheet-fed gravure printing machines or packaging box printing machines. The surface of the printing plate cylinder 2 is engraved with the graphic areas to be printed. This invention replaces the traditional back pressure roller paired with the printing plate cylinder 2 with the flat back pressure roller group 5 as a whole. The lower outer wall of the flat back pressure roller group 5 serves as the imprinting back pressure for the cardboard substrate. The printing back pressure surface is correspondingly arranged above the printing plate cylinder 2. On both sides of the top of the printing plate cylinder 2, there are first arc-shaped spring plates 3 and second arc-shaped spring plates 4 located below the printing back pressure surface of the flat back pressure roller group 5. The arc-shaped protrusions of the first arc-shaped spring plates 3 and second arc-shaped spring plates 4 are located in the non-printing areas on both sides of the paper substrate, usually within the paper cutting edge range, which is generally 3-10mm. Therefore, they will not contact the printed image area, avoiding scratching the printed ink. The first arc-shaped spring plates 3 and second arc-shaped spring plates 4 are elastically raised on the side facing the exit end. The two ends of the first arc-shaped spring plates 3 and second arc-shaped spring plates 4 are fixedly connected to the frame 1.

[0028] The printing back pressure surface below the flat back pressure roller group 5 precisely corresponds to the printing area of ​​the printing plate cylinder 2. The rotating printing plate cylinder 2 is responsible for applying pressure and transferring the image, while the flat back pressure roller group 5 provides a stable and continuous planar support. This arrangement ensures that the back pressure of the paperboard substrate is absolutely uniform across the entire printing width, effectively overcoming the defects of uneven pressure, ink dot deformation, or inaccurate solid printing that may be caused by line contact in the traditional rotary-to-rotary structure. To further optimize the paper handling process, the first arc-shaped spring plate 3 and the second arc-shaped spring plate 4, which are fixed on the frame 1, are located below the outlet and inlet of the printing back pressure surface, respectively. The second arc-shaped spring plate 4 at the inlet end is responsible for gently guiding the paperboard substrate upward and pre-attaching it to the printing back pressure surface below the flat back pressure roller group 5. The first arc-shaped spring plate 3 at the outlet end assists the paperboard substrate to detach smoothly.

[0029] Reference Figure 1 , Figure 2The planar back pressure roller assembly 5 includes an active synchronizing roller 51 and a tension synchronizing roller 55, which are arranged in parallel. A rigid support component 54 is meshed with the periphery of the active synchronizing roller 51 and the tension synchronizing roller 55. The rigid support component 54 surrounds the periphery of the active synchronizing roller 51 and the tension synchronizing roller 55. A support roller 52 is provided in the upper inner ring of the rigid support component 54. An impression backing belt 53 is provided around the periphery of the rigid support component 54. The outer ring of the rigid support component 54 is tightly meshed with the inner wall of the impression backing belt 53. The lower side is rigidly supported by the rigid support component 54 to form a flat imprint back pressure surface. The ends of the active synchronous roller 51, tension synchronous roller 55 and support roller 52 are all connected by support frames 56. The support frame 56 in the planar back pressure roller group 5 is fixedly installed on the frame 1. The two ends of the active synchronous roller 51 are rotatably connected to the support frame 56 through bearings. The lower part of the support frame 56 is provided with a transverse groove 561. A crossbar 562 is telescopically connected in the transverse groove 561. The end of the tension synchronous roller 55 is rotatably connected to the end of the crossbar 562 through bearings.

[0030] The active synchronizing roller 51 and the tension synchronizing roller 55 serve as the basis for driving and tensioning. They form a closed-loop load-bearing structure through the rigid support component 54 surrounding them. The added support roller 52 acts on the upper inner ring of the rigid support component 54 and cooperates with the lower active synchronizing roller 51 and tension synchronizing roller 55 to initially regulate the running loop of the rigid support component 54. The imprinting backing strip 53 is closely attached to the outer periphery of the rigid support component 54 and, using the rigidity of the rigid support component 54 on the lower side, jointly shapes a flat imprinting back pressure surface. This is the key to replacing the traditional back pressure roller. The support frame 56, which is fixedly connected to the frame 1, is used to uniformly support the active synchronizing roller 51, the tension synchronizing roller 55, and the support roller 52. The tension synchronizing roller 55 achieves limited extension and retraction within the transverse groove 561 of the support frame 56 through the crossbar 562 connected to its end.

[0031] refer to Figure 2 , Figure 3 , Figure 4A large spring 563 in a compressed state is provided inside the transverse groove 561. One end of the large spring 563 is connected to the crossbar 562, and the outer wall of the large spring 563 is in contact with the inner wall of the transverse groove 561. A vertical groove 566 in a vertical state is provided above the support frame 56. A vertical bar 569 is telescopically connected to the vertical groove 566. A small spring 568 in a compressed state is provided inside the vertical groove 566. The top of the small spring 568 is connected to the bottom of the vertical bar 569, and the outer wall of the small spring 568 is in contact with the inner wall of the vertical groove 566. The two ends of the support roller 52 are respectively connected to the two vertical bars 569. The top of the rotatable connection is provided. A first limiting hole 565 is provided on one side of the horizontal groove 561. The horizontal groove 561 is connected to the first limiting hole 565. A first bolt 564 threadedly connected to the horizontal bar 562 is slidably connected in the first limiting hole 565. A second limiting hole 567 is provided on one side of the vertical groove 566. The vertical groove 566 is connected to the second limiting hole 567. A second bolt 570 threadedly connected to the vertical bar 569 is provided in the second limiting hole 567. A pressure block 57 fixedly connected to the support frame 56 is provided in the inner ring of the rigid support component 54.

[0032] Within the transverse groove 561, the large spring 563, under compression, continuously applies an outward pushing force to the crossbar 562, thereby forcing the tension synchronizing roller 55 connected to the crossbar 562 away from the active synchronizing roller 51. This automatically tensions the surrounding rigid support member 54 and ensures that the lower part of the rigid support member 54 is effectively expanded to form a flat surface. Within the vertical groove 566, the small spring 568, under compression, pushes the vertical bar 569 upward, allowing the support roller 52, rotatably connected to the top of the vertical bar 569, to elastically abut against the rigid support member 54. The upper inner ring adapts to the operation of the rigid support component 54 and provides stable support. The first bolt 564 moves with the crossbar 562 but is limited in the first limiting hole 565 to prevent the crossbar 562 from coming out. The second bolt 570 limits the lifting range of the vertical bar 569 by cooperating with the second limiting hole 567. The pressure block 57, fixed on the support frame 56, is directly set in the inner ring of the rigid support component 54 to provide additional rigid support from the back for the critical section that will bear the printing pressure and prevent deformation.

[0033] refer to Figure 3 , Figure 5 , Figure 6The rigid support component 54 includes several round rods 541 and several chain plates 542. The round rods 541 are arranged in parallel, and both ends of each round rod 541 are coaxially fixed with a cylinder 543. The two ends of the chain plates 542 are rotatably connected to the cylinders 543 at the ends of two adjacent round rods 541. The smooth and flat surface below the pressure block 57 contacts the round rods 541 in the rigid support component 54. The outer wall of the active synchronous roller 51 is provided with several... The outer wall of the cylindrical rod 541 is provided with a first groove 511, and the outer wall of the tension synchronization roller 55 is provided with a number of fourth grooves 551 that mesh with the outer walls of the cylindrical rods 541 in the rigid support component 54. The outer wall of the support roller 52 is provided with a number of second grooves 521 that mesh with the outer walls of the cylindrical rods 541 in the rigid support component 54. The inner wall of the embossing tape 53 is provided with a third groove 531, and the third groove 531 meshes with the outer walls of the cylindrical rods 541 in the rigid support component 54.

[0034] A rigid support component 54, consisting of several parallel arranged round rods 541, a cylinder 543, and a chain plate 542, combines the characteristics of rigid support and flexible hinge. The smooth lower surface of the pressure block 57 directly contacts the parallel round rods 541, providing back support for the round rods 541 in the printing area, dispersing the concentrated printing pressure, and ensuring the uniformity and rigidity of the support. The active synchronization roller 51 engages with the round rods 541 through the first rod groove 511 on the outer wall, inputting power. The tension synchronization roller 55, through the fourth rod groove 551, and the support roller 52, through the second rod groove 521, constrain and guide the movement trajectory of the round rods 541 from below and above, respectively. The printing backing belt 53 engages with the outer wall of the round rods 541 through the third rod groove 531 on the inner wall, transmitting the linear movement of the rigid support component 54 into the planar movement of the printing backing belt 53 without slippage.

[0035] It should be further explained that, in order to achieve precise synchronization between the high-speed circular motion of the printing plate cylinder 2 and the linear motion of the printing press belt 53, this equipment adopts a mature electronic shaft servo control system. The printing plate cylinder 2 and the active synchronization roller 51 are driven by independent servo motors. The system's main controller monitors their positions in real time through a high-resolution encoder and dynamically adjusts the driven shaft speed using a virtual spindle and sliding mode observer algorithm. This ensures that, even at speeds up to 200 m / min, the synchronization error is stably controlled within ±0.05 mm, thereby fundamentally eliminating ghosting and misregistration caused by speed mismatch. To address the issue of inaccuracy, and in response to the high-speed sliding friction between the pressure block 57 and the round rod 541, a composite self-lubricating sliding plate made of polyetheretherketone (PEEK) is installed on the working surface of the pressure block 57. This ensures the stability and reliability of the support plane under long-term operation, eliminating the need for lubrication and preventing contamination of printed materials. The printing backing tape 53 is made of Kevlar fiber-reinforced composite polyurethane material. The high-strength tensile layer of the printing backing tape 53 effectively inhibits creep under high-speed tension, while the wear-resistant composite polyurethane working surface ensures the long-term flatness and ink resistance of the printing surface. Together, these factors ensure the long-term stable operation and excellent printing quality of this equipment in high-speed, high-pressure industrial environments.

[0036] The implementation principle of a printing equipment for gravure printing of packaging boxes according to an embodiment of this application is as follows: In the printing production process of thick cardboard substrates with strict requirements for printing quality, such as high-end gift boxes and electronic product packaging, when the cardboard to be printed is transferred to this equipment from the previous conveyor system, it first passes through the second arc-shaped spring sheet 4 located at the inlet end and in the non-printing area on both sides of the paper edge, so that it is flatly pre-attached to the uniformly running imprinting belt 53. Subsequently, the cardboard is fed into the printing imprinting area composed of a high-speed rotating printing plate cylinder 2 and a flat back pressure roller group 5. This area forms a continuous paper feeding circular pressing structure. In the printing plate cylinder 2, the ink in the cells on the surface of the printing plate is transferred to the surface of the paperboard under pressure. The key is that the support on the back of the paperboard is an absolutely flat and deformation-free imprinting back pressure surface constructed by the rigid support component 54 and the pressure block 57. This ensures that even in large-format solid full-page printing, the pressure on the back of the paperboard is uniform and consistent, thus effectively avoiding the ghosting, uneven ink layer, or paperboard deformation caused by excessive pressure that are easy to produce in the rotary printing method. After printing is completed, the paperboard is smoothly separated from the imprinting backing belt 53 at the exit end with the assistance of the first arc-shaped spring sheet 3, which is also located on both sides of the paper.

[0037] The above are merely optional embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A printing apparatus for gravure printing of packaging boxes, comprising a frame (1) and a printing plate cylinder (2) mounted on the frame (1), characterized in that: A planar back pressure roller group (5) is provided on the frame (1) at the position corresponding to the printing area of ​​the printing plate cylinder (2). The planar back pressure roller group (5) includes a parallel active synchronous roller (51) and a tension synchronous roller (55). The active synchronous roller (51) and the tension synchronous roller (55) are surrounded and meshed with a rigid support member (54). The rigid support member (54) is tightly connected to an impression backing belt (53). The side of the impression backing belt (53) near the printing plate cylinder (2) forms a flat impression back pressure surface through the rigid support member (54).

2. The printing equipment for gravure printing of packaging boxes according to claim 1, characterized in that: Support frames (56) are connected between the two ends of the active synchronizing roller (51) and the tension synchronizing roller (55). The support frames (56) are fixedly connected to the frame (1). The end of the active synchronizing roller (51) is rotatably connected to the support frame (56). A transverse groove (561) is provided below the support frame (56). A crossbar (562) is telescopically connected in the transverse groove (561). The end of the tension synchronizing roller (55) is rotatably connected to the end of the crossbar (562). A large spring (563) is provided in the transverse groove (561) and compressedly connected to the crossbar (562).

3. The printing equipment for gravure printing of packaging boxes according to claim 2, characterized in that: The support frame (56) has a vertical groove (566) above it. A vertical rod (569) is telescopically connected in the vertical groove (566). A small spring (568) is provided in the vertical groove (566) and compressedly connected to the vertical rod (569). A support roller (52) is rotatably connected between the top ends of the two vertical rods (569). The support roller (52) is located above the inner ring of the rigid support component (54).

4. The printing equipment for gravure printing of packaging boxes according to claim 3, characterized in that: The rigid support component (54) includes several parallel circular rods (541) and several chain plates (542) connected to the ends of adjacent circular rods (541). Both ends of the circular rods (541) are coaxially provided with cylinders (543), and both ends of the chain plates (542) are rotatably connected to the cylinders (543) at the ends of the circular rods (541).

5. The printing equipment for gravure printing of packaging boxes according to claim 3, characterized in that: One side of the horizontal groove (561) is connected to a first limiting hole (565), and a first bolt (564) is slidably connected in the first limiting hole (565). One end of the first bolt (564) is threadedly connected to the horizontal bar (562). One side of the vertical groove (566) is connected to a second limiting hole (567), and a second bolt (570) is provided in the second limiting hole (567). The second bolt (570) is threadedly connected to the vertical bar (569).

6. The printing equipment for gravure printing of packaging boxes according to claim 4, characterized in that: A pressure block (57) is provided in the inner ring of the rigid support component (54). The pressure block (57) is fixedly connected to the frame (1). The lower surface of the pressure block (57) is in contact with several round rods (541) in the rigid support component (54).

7. The printing equipment for gravure printing of packaging boxes according to claim 4, characterized in that: The inner wall of the embossed liner (53) is provided with several third rod grooves (531) that mesh with the outer wall of several round rods (541) in the rigid support component (54).

8. The printing equipment for gravure printing of packaging boxes according to claim 1, characterized in that: The printing plate cylinder (2) has a first arc-shaped spring sheet (3) and a second arc-shaped spring sheet (4) located on the non-printing areas on both sides of the substrate. The first arc-shaped spring sheet (3) and the second arc-shaped spring sheet (4) are located below the printing back pressure surface of the flat back pressure roller group (5). The first arc-shaped spring sheet (3) and the second arc-shaped spring sheet (4) are fixedly connected to the frame (1).

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