A laser printing machine and printing method

Abstract

This application discloses a laser printing machine and printing method, belonging to the field of printing technology. The laser printing machine is used to imprint a laser pattern from a transfer film onto a UV varnish area of ​​packaging paper. It includes a mounting section; a PLC control system mounted on the mounting section; an imprinting conveyor mounted within the mounting section; a film-pressing roller mounted on the mounting section; and a position adjustment assembly, with two sets of position adjustment assemblies mounted on both sides of the film-pressing roller. The position adjustment assemblies are used to adjust the height of the film-pressing roller. Specifically, the position adjustment assemblies are adapted to automatically detect the thickness of the packaging paper and adjust the film-pressing roller to a fixed imprinting position after the transfer film is installed, and to automatically adjust the film-pressing roller away from the imprinting conveyor when the transfer film is not installed. This laser printing machine and printing method achieves the effect of automatically adjusting the height of the film-pressing roller.

Description

Technical Field

[0001] This application relates to the field of printing technology, specifically to a laser printer and printing method. Background Technology

[0002] In the paper packaging printing industry, embossing transfer machines are a type of laser printing machine. Their main function is laser embossing transfer, which is derived from the laser film molding process in the laser paper manufacturing process. The laser embossing transfer process utilizes the principle of imaging the pattern on the surface of the laser film through extremely fine concave and convex designs, as well as the characteristics of strong plasticity and instantaneous and complete curing before UV varnish curing. UV varnish is applied to the surface of the printed material, and before the UV varnish cures, the patterned laser film is pressed onto it. Using the concave and convex patterns on the surface of the laser film as a mold, a concave and convex pattern consistent with the pattern on the surface of the laser film is embossed on the UV varnish surface. After the UV varnish cures, the laser pattern is formed.

[0003] Some malfunctions often occur during laser embossing transfer. For example, the laser transfer film itself may not have quality problems, but it may wrinkle as soon as it is pressed. This is mainly due to the unbalanced pressure at both ends of the pressure roller during laser embossing transfer. In this case, it is necessary to adjust the pressure limit screw at the end of the cylinder stroke. Since it is located inside the wall panel and its position is relatively hidden, it needs to be adjusted with a feeler gauge and tightened in time. Each time the packaging paper of different thickness is changed, the height of both sides of the pressure roller needs to be adjusted to meet the processing requirements of pressure transfer. Manual adjustment is time-consuming and prone to errors, affecting processing efficiency. Therefore, it is necessary to provide a laser printing machine and printing method to solve the above problems.

[0004] It should be noted that the information disclosed in this background section is only for understanding the background technology of the present invention, and therefore may include information that does not constitute prior art. Summary of the Invention

[0005] Based on the above-mentioned problems in the existing technology, the technical problem to be solved by the present invention is to provide a laser printing machine and printing method that achieves the effect of automatically adjusting the height of the pressure roller.

[0006] The technical solution adopted by this application to solve its technical problem is: a laser printing machine and printing method, wherein the laser printing machine is used to imprint a laser pattern on a transfer film onto a UV varnish area on packaging paper, including a mounting part; a PLC control system, the PLC control system being installed on the mounting part; an imprinting conveying component, the imprinting conveying component being installed inside the mounting part; a film pressing roller, the film pressing roller being installed on the mounting part; and a position adjustment assembly, two sets of the position adjustment assembly being installed on both sides of the film pressing roller, the position adjustment assembly being used to adjust the height position of the film pressing roller; wherein: the position adjustment assembly is adapted to automatically detect the thickness of the packaging paper and adjust the film pressing roller to move to a fixed imprinting position after the transfer film is installed, and the position adjustment assembly is adapted to automatically adjust the film pressing roller away from the imprinting conveying component when the transfer film is not installed.

[0007] Furthermore, the position adjustment assembly includes two sets of guide blocks mounted on the mounting part, a lifting block slidably connected between the two sets of guide blocks, the lifting block being connected to the pressure roller bearing, a cylinder being provided above the lifting block, the cylinder being fixedly connected to the lifting block, and the cylinder being adapted to control the pressure roller to move vertically up and down under the action of the PLC control system.

[0008] Furthermore, the position adjustment assembly also includes pulleys installed on the upper ends of the two sets of guide blocks, with steel wire ropes placed on the pulleys. The opposite ends of the two sets of steel wire ropes are fixedly connected to the lifting block, and counterweights are fixedly installed on the opposite ends of the two sets of steel wire ropes. In the case where the cylinder is not vented, the steel wire ropes are adapted to balance the tension at both ends when the transfer membrane is installed.

[0009] Furthermore, a distance sensor is disposed directly above the counterweight, the distance sensor being used to detect the height of the counterweight, and an electromagnet is disposed directly below the counterweight, the electromagnet being electrically connected to the PLC control system, the distance sensor being signal-connected to the PLC control system, and the counterweight being made of magnetic material; wherein: the distance sensor is adapted to provide an energizing signal to the electromagnet through the PLC control system when it detects that the film pressing roller has moved to contact the printing conveyor component.

[0010] Furthermore, a pressure sensor is provided directly below the counterweight. The pressure sensor is adapted to give the electromagnet a de-energizing signal when it is subjected to pressure, and at the same time give the cylinder an extension signal.

[0011] Furthermore, a cooperating spring is installed between the cylinder and the lifting block. The cooperating spring is used to apply a force to the lifting block away from the cylinder. In the case where the transfer membrane is not installed, the counterweight cannot contact the pressure sensor under the action of the magnetic force of the electromagnet and the elastic force of the cooperating spring. When the transfer membrane is installed, the counterweight applies pressure to the pressure sensor under the action of the magnetic force of the electromagnet, the elastic force of the cooperating spring, and the upward pulling force of the transfer membrane.

[0012] Furthermore, a servo motor is installed at the lower end of the guide block on one side. The servo motor is electrically connected to the PLC control system. A screw is fixedly connected to the output shaft of the servo motor. A limit block is slidably connected to the guide block in the vertical direction. The limit block is threadedly connected to the screw. The limit block is used to limit the extreme position of the lifting block sliding downward.

[0013] Furthermore, the steel wire rope is made of stainless steel.

[0014] Furthermore, the printing method includes:

[0015] S1. Power on the pressure roller to check if a transfer film is installed;

[0016] S2. When the transfer film is not installed, the pressure roller is automatically adjusted to move to the installation position of the transfer film;

[0017] S3. After the transfer film installation is completed or the power is turned on to detect that the transfer film has been installed, the pressure roller is automatically adjusted to move to the packaging paper thickness detection position.

[0018] S4. Place the packaging paper through the film pressing roller to check its thickness;

[0019] S5. Adjust and fix the limit height of the pressure roller according to the detection value;

[0020] S6. Laser printing machine is operating normally.

[0021] The beneficial effects of this application are as follows: The laser printing machine and printing method provided by this application, through the cooperation of the position adjustment component and the pressure roller, realize the automatic adjustment of the pressure roller to a convenient installation position when the transfer film is not installed, the automatic adjustment to the position for detecting the thickness of the packaging paper after the transfer film is installed, and the automatic adjustment of the imprinting position of the pressure roller based on the detection result, which is simple and convenient to operate.

[0022] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0024] In the attached diagram:

[0025] Figure 1 This is an overall schematic diagram of a laser printing machine and printing method according to this application;

[0026] Figure 2 for Figure 1 Overall internal diagram of the middle casing;

[0027] Figure 3 for Figure 2 A side view diagram;

[0028] Figure 4 for Figure 2 Enlarged view of region A in the middle;

[0029] Figure 5 for Figure 4 A schematic diagram showing the installation position of the laser film;

[0030] The following are the labeling elements in the figure:

[0031] 1. Laser printing machine; 2. Housing; 3. Feeding conveyor; 4. Discharge conveyor; 5. Unwinding roller; 6. Rewinding roller; 7. Central control screen; 8. Mounting unit; 9. Pressing roller; 10. Curing assembly; 11. Separating roller; 12. Imprinting conveyor; 13. Guide block; 14. Lifting block; 15. Pulley; 16. Wire rope; 17. Matching spring; 18. Distance sensor; 19. Counterweight; 20. Pressure sensor; 21. Electromagnet; 22. Servo motor; 23. Screw; 24. Limit block; 25. Cylinder. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0034] like Figure 1-3As shown, this application provides a laser printing machine and printing method. The laser printing machine 1 is used to imprint a laser pattern on a transfer film onto the UV varnish on packaging paper. In this application, the laser printing machine 1 is specifically an imprinting transfer machine.

[0035] The laser printing machine 1 includes a mounting section 8, which consists of two stainless steel plates used to fix and install various parts inside the laser printing machine 1. A PLC control system is fixedly installed on the inner side of the mounting section 8. The PLC control system is used to control the various parts of the laser printing machine 1 when it is working. A cover 2 is fixedly installed on the outer side of the mounting section 8. The cover 2 is used to decorate the exterior of the laser printing machine 1 and to provide a certain degree of sealing. A central control screen 7 is fixedly installed on the front side of the cover 2. The central control screen 7 is electrically connected to the PLC control system. The laser printing machine 1 can be started, stopped, and its overall operating parameters can be set on the central control screen 7.

[0036] A feeding conveyor 3 is fixedly installed on the right end of the mounting part 8. The feeding conveyor 3 is used to feed the packaging paper coated with UV varnish into the laser printing machine 1. A discharging conveyor 4 is fixedly installed on the left side of the mounting part 8. The discharging conveyor 4 is used to send the printed packaging paper out of the laser printing machine 1. An imprinting conveyor 12 is fixedly installed on the inner side of the mounting part 8. The imprinting conveyor 12 is used to carry the packaging paper that enters the laser printing machine 1 for imprinting transfer, and to convey the packaging paper from the feeding conveyor 3 to the discharging conveyor 4. The feeding conveyor 3, the discharging conveyor 4 and the imprinting conveyor 12 all have independent power units and keep moving synchronously.

[0037] The upper bearing of the mounting section 8 connects to an unwinding roller 5 and a take-up roller 6. The unwinding roller 5 is located on the side near the feeding conveyor 3, and the take-up roller 6 is located on the side near the discharging conveyor 4. Multiple sets of transition rollers are fixedly installed inside the mounting section 8. A pressing roller 9 is installed on the side of the mounting section 8 near the feeding conveyor 3. An imprinting motor is fixedly installed on the rear side of the mounting section 8. The imprinting motor is electrically connected to the PLC control system. The imprinting motor and the pressing roller 9 are connected and driven by a sliding universal joint. This sliding universal joint connection allows for the pressing... When the film roller 9 moves vertically, it will not affect the rotation of the pressure roller 9 driven by the printing motor. The bearing of the mounting part 8 near the discharge conveying component 4 is connected to the separation roller 11. The unwinding roller 5 is wound with a transfer film with a laser pattern. The transfer film is pulled out from the unwinding roller 5 and passes through the transition roller, pressure roller 9, separation roller 11, and transition roller in sequence. Finally, it is wound onto the winding roller 6 for winding. The winding roller 6 is equipped with a power source so that the winding speed of the transfer film matches the moving speed of the printing conveying component 12.

[0038] A curing component 10 is also fixedly installed inside the mounting part 8. The curing component 10 mainly consists of a rectangular frame, an ultraviolet lamp installed inside the frame, and a cooling fan fixedly installed on the frame. The ultraviolet lamp irradiates the upper surface of the printing conveying part 12 to cure the UV varnish. The cooling fan is used to control the temperature at the curing component 10, thereby avoiding the high temperature from affecting the printing transfer of the packaging paper. The curing component 10 is located between the pressing roller 9 and the separating roller 11.

[0039] When the packaging paper coated with UV varnish is conveyed from the feeding conveyor 3 to the imprinting conveyor 12, the film pressing roller 9 will press the transfer film and the packaging paper together. The pressed packaging paper moves towards the separation roller 11 along with the imprinting conveyor 12. When the packaging paper moves below the curing component 10, the ultraviolet lamp will irradiate the UV varnish on the packaging paper to cure it, so that the laser pattern on the transfer film coated with UV varnish will detach from the transfer film and stick to the packaging paper. When the packaging paper moves to the separation roller 11, the transfer film moves and is wound up towards the upper winding roller 6 along with the outer wall of the separation roller 11, so that the transfer film is separated from the packaging paper. The laser pattern cured on the packaging paper will move with the packaging paper to the discharge conveyor 4, thus completing the laser printing operation on the packaging paper.

[0040] Because the thickness of packaging paper varies, in order to ensure that the printing effect of packaging paper of different thicknesses is not affected, the distance between the pressing roller 9 and the printing conveying component 12 must be adjusted according to the thickness of the packaging paper, that is, the vertical height of the pressing roller 9. However, if the pressing roller 9 is too close to the printing conveying component 12, it will be more difficult to operate when the transfer film passes through the pressing roller 9 when changing the transfer film.

[0041] Therefore, position adjustment components are symmetrically arranged on both sides of the film pressing roller 9 in the axial direction. Under the control of the PLC control system, the two sets of position adjustment components move synchronously. The position adjustment components are adapted to automatically detect the thickness of the packaging paper and adjust the film pressing roller 9 to move to the imprinting position after the transfer film is installed. The position adjustment components are adapted to automatically adjust the film pressing roller 9 away from the imprinting conveyor component 12 when the transfer film is not installed. Its structure is as follows:

[0042] like Figure 4As shown, the position adjustment assembly includes two sets of guide blocks 13 fixedly installed on the mounting part 8. A lifting block 14 is slidably connected between the two sets of guide blocks 13. The lifting block 14 is connected to a bearing on one side of the pressure roller 9. A cylinder 25 is fixedly installed on the mounting part 8. The cylinder 25 is located above the lifting block 14. The cylinder shaft end of the cylinder 25 is fixedly connected to the upper end of the lifting block 14 by a nut. An air source is fixedly installed on the mounting part 8. A solenoid valve connected to the air source is installed in the PLC control system. The cylinder 25 is connected to the solenoid valve. The cylinder shaft of the cylinder 25 can be controlled to extend and retract through the PLC control system.

[0043] When the cylinder shaft of cylinder 25 extends, it will drive the lifting block 14 to move downward. When the cylinder shaft of cylinder 25 retracts, it will drive the lifting block 14 to move upward. The cylinders 25 in the position adjustment components on both sides of the pressure roller 9 move synchronously, which can realize the vertical lifting control of the pressure roller 9.

[0044] like Figure 4 As shown, the position adjustment assembly also includes pulleys 15 installed on the upper ends of the two sets of guide blocks 13. Steel wire ropes 16 are placed on the pulleys 15. When the steel wire ropes 16 slide on the pulleys 15 at both ends, the friction between the steel wire ropes 16 and the pulleys 15 can be reduced by the rotation of the pulleys 15, thereby reducing wear and increasing the service life of the steel wire ropes 16. The steel wire ropes 16 are made of stainless steel to avoid rusting after long-term use. The opposite ends of the two sets of steel wire ropes 16 are fixedly connected to the lifting block 14, and the opposite ends of the two sets of steel wire ropes 16 are fixedly installed with counterweights 19.

[0045] A distance sensor 18 is fixedly installed on the guide block 13. The distance sensor 18 is located directly above the counterweight block 19. The distance sensor 18 is used to detect the height position of the counterweight block 19. Since the counterweight block 19 and the lifting block 14 are connected by a steel wire rope 16, the height position of the counterweight block 19 and the height position of the lifting block 14 can be linearly converted. An electromagnet 21 is fixedly installed on the guide block 13. The electromagnet 21 is located directly below the counterweight block 19. The electromagnet 21 is electrically connected to the PLC control system. The distance sensor 18 is signal connected to the PLC control system. The counterweight block 19 is made of magnetic material.

[0046] The central control screen 7 is equipped with adjustment function keys. When the laser printing machine 1 is powered on, the central control screen 7 lights up. Pressing the adjustment function key will start to automatically adjust the position of the pressure roller 9. In the initial state, the cylinder 25 is in the non-air-ventilated state. When the adjustment function key is pressed, the cylinder 25 will be ventilated so that the internal cylinder shaft extends. When the cylinder shaft extends to the pressure position where it can no longer extend, the air is automatically cut off. The height position of the counterweight 19 is detected by the distance sensor 18. When the distance sensor 18 detects that the pressure roller 9 has moved to the position of contacting the printing conveyor component 12, the PLC control system determines that no transfer film is installed and sends an energizing signal to the electromagnet 21 through the PLC control system.

[0047] like Figure 5 As shown, when the electromagnet 21 is energized, it generates magnetism and attracts the counterweight 19, thereby generating an upward pulling force on the lifting block 14 through the steel wire rope 16, which drives the pressing roller 9 to move upward away from the printing conveyor component 12. At this time, the distance between the pressing roller 9 and the printing conveyor component 12 is large, which facilitates the installation of the transfer film.

[0048] In order to enable the pressure roller 9 to automatically reach the position for detecting the thickness of the packaging paper after the transfer film is installed, a pressure sensor 20 is fixedly connected to the guide block 13 directly below the counterweight block 19. The pressure sensor 20 is adapted to give the electromagnet 21 a de-energizing signal when pressure is applied, and at the same time give the cylinder 25 an extension signal. A cooperating spring 17 is fixedly installed on the upper end of the lifting block 14. The cooperating spring 17 is used to give the lifting block 14 a force away from the cylinder body of the cylinder 25.

[0049] When the transfer film is not installed, the magnetic attraction of the electromagnet 21 to the counterweight 19 is less than the elastic force of the spring 17 on the lifting block 14. This prevents the counterweight 19 from contacting the pressure sensor 20 when the pressure roller 9 rises to the position where the transfer film is installed. After the transfer film is installed, it is pulled out from the unwinding roller 5, passes under the pressure roller 9 and the separating roller 11, and finally winds onto the winding roller 6. This causes the transfer film to exert an upward pulling force on the pressure roller 9. Under this pulling force, the lifting block 14 will overcome the elastic force of the spring 17, thereby causing the counterweight 19 to slide towards the pressure sensor 20 and apply pressure to it. When the pressure sensor 20 is under pressure, it will send a signal to the PLC control system. The PLC control system will send a power-off signal to the electromagnet 21 and simultaneously send a signal to the cylinder 25 to extend, causing the pressure roller 9 to slide down to the position where the transfer film contacts the printing conveyor 12, which is the thickness detection position of the packaging paper. This realizes that the pressure roller 9 automatically adjusts to the thickness detection position of the packaging paper after the transfer film is installed.

[0050] To improve the accuracy of packaging paper thickness detection, it is necessary to reduce the pressure exerted on the packaging paper by the pressure roller 9. Therefore, the counterweight 19 is set to be suspended in the air. The tension on the end of the steel wire rope 16 connected to the counterweight 19 is the weight of the counterweight 19.

[0051] With the cylinder 25 de-aired and the transfer film already installed, the tension at the end of the steel wire rope 16 connected to the lifting block 14 is the sum of the weight of the pressure roller 9, the weight of the cylinder shaft of the cylinder 25, and the weight of the lifting block 14, minus the upward tension of the transfer film on the pressure roller 9 and the frictional resistance of each component. At this time, the tension at both ends of the steel wire rope 16 is balanced, so that the two sets of counterweights 19 in the position adjustment components on both sides of the pressure roller 9 maintain a state of gravitational balance with the pressure roller 9. This allows the pressure roller 9 to be easily lifted when the packaging paper passes through it. The thickness of the packaging paper can be obtained by monitoring the distance of the counterweights 19 by the distance sensor 18.

[0052] In order to automatically adjust the imprinting position of the film pressing roller 9 after detecting the thickness of the packaging paper, a servo motor 22 is fixedly installed at the lower end of the single-sided guide block 13. The servo motor 22 is electrically connected to the PLC control system. A screw 23 is fixedly connected to the output shaft of the servo motor 22. A limit block 24 is slidably connected to the vertical direction of the guide block 13. The limit block 24 is threadedly connected to the screw 23. The operation of the servo motor 22 can drive the limit block 24 to slide up and down in the vertical direction. The limit block 24 is located below the lifting block 14 and in its sliding direction. When the lifting block 14 slides down and contacts the limit block 24, the limit block 24 can limit the extreme position of the downward sliding of the lifting block 14.

[0053] When the pressure roller 9 contacts the printing conveyor component 12, the contact position between the limit block 24 and the lifting block 14 is the initial position of the limit block 24. The central control screen 7 is equipped with a calibration function button. When the distance sensor 18 detects the thickness of the packaging paper, by pressing the calibration function button on the central control screen 7, the PLC control system will adjust the height position of the limit block 24 upward through the servo motor 22. The height of the pressure roller 9 corresponding to the thickness of the packaging paper can be set in the central control screen 7, which is the distance of movement of the limit block 24 obtained by subtracting the pressure distance from the detected thickness of the packaging paper, thereby completing the automatic adjustment of the printing position of the pressure roller 9.

[0054] The central control screen 7 is equipped with a start function key. After the printing position of the film pressing roller 9 is adjusted, pressing the start function key will continuously supply air to the cylinder 25, so that the cylinder 25 and the limit block 24 cooperate to fix the position of the film pressing roller 9 and carry out the normal printing operation of the packaging paper.

[0055] The printing method of the laser printing machine 1 is as follows: When the laser printing machine 1 is powered on, the cylinder 25 is extended by the PLC control system. The cylinder 25 drives the pressure roller 9 to slide towards the printing conveyor component 12 through the lifting block 14. The distance sensor 18 monitors the height of the counterweight 19. The higher the counterweight 19 is, the closer the pressure roller 9 is to the printing conveyor component 12.

[0056] When the cylinder 25 extends to the pressure position where it can no longer extend, the air supply is cut off. If the distance sensor 18 detects that the counterweight 19 has reached the contact position between the pressure roller 9 and the printing conveyor component 12, the PLC control system determines that the transfer film has not been installed and automatically energizes the electromagnet 21 to attract the counterweight 19 to slide downward. Under the drive of the lifting block 14, the pressure roller 9 slides upward away from the printing conveyor component 12 under the tension of the wire rope 16, thus facilitating the installation of the transfer film.

[0057] After the transfer film is installed, the transfer film will exert an upward pulling force on the pressure roller 9, thereby causing the pressure sensor 20 to send a signal to the PLC control system under the pressure of the counterweight 19. After receiving the pressure signal, the PLC control system will de-energize the electromagnet 21 and simultaneously send a signal to the cylinder 25 to extend. When the cylinder 25 extends to the pressure position where it can no longer extend, the air supply will be cut off. At this time, the pressure roller 9 slides to the position for detecting the thickness of the packaging paper, and the two ends of the steel wire rope 16 are in a state of tension balance.

[0058] The packaging paper is placed on the pressure roller 9. The pressure roller 9 slides upward and is lifted up by the thickness of the packaging paper. The distance sensor 18 monitors the sliding distance of the counterweight 19. After the packaging paper has completely passed, the PLC control system controls the servo motor 22 to adjust the height of the limit block 24. When the laser printing machine 1 is working normally, the cylinder 25 is kept in the extended state. The lifting block 14 is blocked by the limit block 24, so that the pressure roller 9 is restricted to the printing height that is suitable for the packaging paper.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A laser printing machine, wherein the laser printing machine is used to imprint a laser-etched pattern on a transfer film onto a UV varnish area of ​​packaging paper, characterized in that: include: Installation section (8); The PLC control system is installed on the mounting unit (8); Imprint conveying component (12) is installed inside the mounting part (8); A pressure roller (9) is mounted on the mounting part (8); A position adjustment assembly, two sets of which are installed on both sides of the pressing roller (9), the position adjustment assembly being used to adjust the height position of the pressing roller (9); Wherein: the position adjustment component is adapted to automatically detect the thickness of the packaging paper and adjust the pressing roller (9) to move to the imprinting position after the transfer film is installed, and the position adjustment component is adapted to automatically adjust the pressing roller (9) away from the imprinting conveying component (12) when the transfer film is not installed. The position adjustment assembly includes two sets of guide blocks (13) mounted on the mounting part (8), and a lifting block (14) is slidably connected between the two sets of guide blocks (13). The lifting block (14) is connected to the bearing of the pressing roller (9). A cylinder (25) is provided above the lifting block (14). The cylinder (25) is fixedly connected to the lifting block (14). The cylinder (25) is adapted to control the pressing roller (9) to move vertically under the action of the PLC control system. The position adjustment assembly also includes pulleys (15) installed on the upper ends of the two sets of guide blocks (13), with steel wire ropes (16) placed on the pulleys (15). The opposite ends of the two sets of steel wire ropes (16) are fixedly connected to the lifting block (14), and counterweights (19) are fixedly installed on the opposite ends of the two sets of steel wire ropes (16). Wherein: when the cylinder (25) is not ventilated, the wire rope (16) is adapted to balance the tension at both ends of the wire rope (16) when the transfer membrane is installed; A distance sensor (18) is provided directly above the counterweight (19), and the distance sensor (18) is used to detect the height of the counterweight (19). An electromagnet (21) is provided directly below the counterweight (19), and the electromagnet (21) is electrically connected to the PLC control system. The distance sensor (18) is signal connected to the PLC control system. The counterweight (19) is made of magnetic material. Wherein: the distance sensor (18) is adapted to give the electromagnet (21) an energizing signal through the PLC control system when it detects that the pressing roller (9) has moved to contact the imprinting conveyor (12); A pressure sensor (20) is provided directly below the counterweight (19). The pressure sensor (20) is adapted to give the electromagnet (21) a de-energization signal when subjected to pressure, and at the same time give the cylinder (25) an extension signal. A cooperating spring (17) is installed between the cylinder (25) and the lifting block (14), the cooperating spring (17) being used to apply a force to the lifting block (14) away from the cylinder (25); Wherein: In the state without the transfer membrane installed, the counterweight (19) cannot contact the pressure sensor (20) under the action of the magnetic force of the electromagnet (21) and the elastic force of the cooperating spring (17). In the state with the transfer membrane installed, the counterweight (19) applies pressure to the pressure sensor (20) under the action of the magnetic force of the electromagnet (21), the elastic force of the cooperating spring (17) and the upward pulling force of the transfer membrane. When the laser printing machine (1) is powered on, the position of the pressure roller (9) is automatically adjusted. In the initial state, the cylinder (25) is not ventilated. The cylinder (25) is ventilated so that the internal cylinder shaft extends. When the cylinder shaft extends to the pressure position where it cannot extend further, the air is automatically cut off. The height position of the counterweight (19) is detected by the distance sensor (18). When the distance sensor (18) detects that the pressure roller (9) has moved to the position of contacting the printing conveyor (12), the PLC control system determines that the transfer film has not been installed and sends an energizing signal to the electromagnet (21) through the PLC control system. When the electromagnet (21) is energized, it generates magnetism and attracts the counterweight (19), thereby generating an upward pulling force on the lifting block (14) through the wire rope (16), which drives the pressing roller (9) to move upward away from the printing conveyor (12). At this time, the distance between the pressing roller (9) and the printing conveyor (12) is large, which facilitates the installation of the transfer film. Without the transfer film installed, the magnetic attraction of the electromagnet (21) to the counterweight (19) is less than the elastic force of the spring (17) on the lifting block (14). This prevents the counterweight (19) from contacting the pressure sensor (20) when the pressure roller (9) rises to the position where the transfer film is installed. After the transfer film is installed, it is pulled out from the unwinding roller (5), passes under the pressure roller (9) and the separating roller (11), and finally winds onto the take-up roller (6) for winding. This causes the transfer film to exert an upward pulling force on the pressure roller (9), which helps to lift the pressure roller. The lowering block (14) overcomes the elastic force of the cooperating spring (17), thereby causing the counterweight block (19) to slide towards the pressure sensor (20) and apply pressure to it. When the pressure sensor (20) is under pressure, it will send a signal to the PLC control system. The PLC control system will give the electromagnet (21) a power-off signal and at the same time give the cylinder (25) an extension signal, so that the pressing roller (9) slides down to the position where the transfer film contacts the printing conveyor (12), which is the thickness detection position of the packaging paper. This realizes that after the transfer film is installed, the pressing roller (9) will automatically adjust to the thickness detection position of the packaging paper.

2. The laser printing machine according to claim 1, characterized in that: A servo motor (22) is installed at the lower end of the guide block (13) on one side. The servo motor (22) is electrically connected to the PLC control system. A screw (23) is fixedly connected to the output shaft of the servo motor (22). A limit block (24) is slidably connected to the guide block (13) in the vertical direction. The limit block (24) is threadedly connected to the screw (23). The limit block (24) is used to limit the extreme position of the downward sliding of the lifting block (14).

3. A laser printing machine according to claim 2, characterized in that: The steel wire rope (16) is made of stainless steel.

4. A printing method for a laser printing machine according to claims 1-3, characterized in that: The printing method includes: S1. Power on the pressure roller to check if a transfer film is installed; S2. When the transfer film is not installed, the pressure roller is automatically adjusted to move to the installation position of the transfer film; S3. After the transfer film installation is completed or the power is turned on to detect that the transfer film has been installed, the pressure roller is automatically adjusted to move to the packaging paper thickness detection position. S4. Place the packaging paper through the film pressing roller to check its thickness; S5. Adjust and fix the limit height of the pressure roller according to the detection value; S6, Laser printing machine is operating normally.

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