Coating and printing method for plate or coiled material

Abstract

The invention discloses a coating and printing method for a plate or a coiled material. The coating and printing method comprises the following steps: S1, preparing equipment; S2, running the plate or the coiled material; when the printing process needs to be carried out, the step S4 is carried out; when the coating process needs to be carried out, the step S3 is carried out; s3, a coating process is conducted, specifically, the transfer printing roller is dismantled, the pickup roller is immersed in the paint in the paint tray, the pickup roller picks up the paint and transfers the paint into the coating roller, and the coating roller is fixed in thickness and then coats the surface of the plate or the coiled material; s4, a printing process is conducted, specifically, a coating roller is detached, and a printing roller is replaced; the thickness determining roller and the picking roller are far away from the printing roller; paint drips through the liquid dropping pipe, the printing scraper device is used for conducting blade coating on the surface of the printing roller to form a paint film with the specified thickness, the printing roller conducts transfer printing to the transfer printing roller, and printing is conducted on the surface of the plate or the coiled material in the advancing direction of the plate or the coiled material. According to the coating and printing method, rapid switching of a coating process or a printing process can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of coating and printing of plates or coils, and in particular to a coating and printing method for plates or coils. Background Art

[0002] At present, in the process of forming aluminum-plastic panels or metal composite panels, in order to enrich the aesthetics of the panels or coils, the surfaces of the panels or coils are painted or printed during the operation of the panels or coils. The applicant applied for a coating machine for panels or coils in 2014, and its patent publication number is CN104190589A. The coating machine uses two sets of coating mechanisms to paint the surfaces of panels and coils, so as to achieve non-stop operation. Each coating mechanism includes a coating roller, a pick-up roller and a thickness setting roller. The pick-up roller picks up the paint in the paint tray, and then uses the thickness setting roller to apply the paint to the coating roller, and then uses the coating roller and the backing roller to cooperate to apply the paint on the surface of the panel or coil. Since coating and printing are two different processes, printing is to print patterns on the surface of the panel or coil, and the amount of paint picked up on the paint tray by the pick-up roller is too large. Therefore, even if the printing roller is replaced, a clear pattern cannot be printed. Therefore, the current coating machine can only paint, and printing cannot be achieved even if the coating roller is replaced with a printing roller. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a coating and printing method for a plate or a coil, which can realize rapid switching of coating or printing processes.

[0004] In order to solve the above technical problems, the technical solution of the present invention is: a coating and printing method for a plate or a coil, comprising the following steps:

[0005] S1. Equipment preparation:

[0006] A coating and printing machine for plates or coils is provided, comprising a frame, on which a steering roller and a backing roller are rotatably mounted, the coating and printing machine also comprises a first bracket slidably mounted on the frame and located outside a mounting seat for the backing roller, a first position adjustment device for driving the first bracket to approach or move away from the backing roller is arranged between the frame and the first bracket, a transfer roller is detachably and rotatably mounted on the first bracket, a second bracket is slidably mounted on the first bracket, a coating roller is detachably and rotatably mounted on the second bracket, a second position adjustment device for driving the second bracket to slide is arranged on the first bracket, a pick-up roller is also rotatably mounted on the second bracket, and the pick-up roller is located Below the coating roller, a paint tray is provided on the frame below the pick-up roller, the paint tray contains paint, and the roller surface of the pick-up roller is partially immersed in the paint; a thickness-fixing roller frame is slidably mounted on the second bracket, a third position adjustment device for driving the thickness-fixing roller frame to slide is mounted on the second bracket, a thickness-fixing roller is rotatably mounted on the thickness-fixing roller frame, the pick-up roller and the thickness-fixing roller are both in contact with the coating roller, the sliding direction of the thickness-fixing roller frame and the second bracket is the same as the sliding direction of the first bracket, a dropper and a printing scraper device used in printing but not in coating are also mounted on the second bracket above the coating roller, and the dropper is connected to a liquid supply system;

[0007] S2, the plate or coil passes through the steering roller and the backing roller in turn during the operation; when the coating process is required, it goes to step S3; when the printing process is required, it goes to step S4;

[0008] S3. Coating process

[0009] The transfer roller is removed, and the coating printing machine is adjusted. The coating roller is moved closer to the backing roller by using the first position adjustment device and the second position adjustment device and finally pressed against the surface of the plate or coil. The pick-up roller is immersed in the paint in the paint tray. The third position adjustment device drives the thickness setting roller to contact the coating roller. The printing scraper device is separated from the coating roller. The equipment is started, and the pick-up roller picks up the paint in the paint tray and transfers the paint to the coating roller. The coating roller rotates against the running direction of the plate or coil and first contacts with the thickness setting roller to set the thickness of the paint film adhering to the surface of the coating roller, and then is coated on the surface of the plate or coil against the running direction of the plate or coil.

[0010] S4. Printing process

[0011] The coating roller is disassembled and the printing roller is replaced; the coating printing machine is adjusted so that the pickup roller is not immersed in the paint, and the thickness roller is driven away from the printing roller by the third position adjustment device; the liquid supply system drips the paint onto the surface of the printing roller through the drip tube, and then the printing scraper device is used to scrape the surface of the printing roller to form a paint film of a specified thickness, the paint film on the printing roller contacts the transfer roller and transfers the paint film to the transfer roller, and the transfer roller cooperates with the backing roller to print on the surface of the plate or coil along the traveling direction of the plate or coil.

[0012] Preferably, the height of the backing roller is adjustable. When the printing process is adopted, the height of the backing roller is adjusted so that the roller surfaces of the backing roller and the transfer roller press against each other on the surface of the plate or coil; when the coating process is adopted, the height of the backing roller is adjusted so that the backing roller is higher than the coating roller, and the position where the coating roller contacts the plate or coil is on the upstream side of the rotation of the backing roller. Therefore, during printing, the backing roller and the transfer roller press against each other, which can provide the extrusion force required for printing and ensure that the pattern is clear during printing; and during coating, the coating roller does not press against the backing roller, so that the paint is directly coated on the surface of the plate or coil, so that the extrusion force will not be too large, thereby ensuring that the thickness of the paint film applied is appropriate.

[0013] Preferably, the adjustment method for the pickup roller not to be immersed in the paint in step S4 is: raising the height of the pickup roller or / and lowering the height of the paint tray, so that the adjustment is more flexible.

[0014] Preferably, a main bracket is also slidably mounted on the frame, and the sliding direction of the main bracket is the same as the sliding direction of the first bracket. A main linear power device that drives the main bracket to slide is installed on the frame, and the first bracket is slidably mounted on the main bracket. The first position adjustment device is installed between the main bracket and the first bracket. The sliding of the main bracket is used to coarsely adjust the distance between the coating roller and the plate or coil surface, and then the position of the second bracket is adjusted to fine-tune the contact extrusion pressure between the coating roller and the plate or coil surface. In this way, the sliding of the main bracket can be driven by the main linear power device, thereby realizing automatic position switching.

[0015] Preferably, a cleaning pipe and a cleaning scraper device for cleaning the transfer roller are arranged on the first bracket above the transfer roller. When the paint for printing needs to be replaced, the cleaning pipe sprays cleaning liquid to clean the roller surface of the transfer roller, and the cleaning scraper device scrapes the roller surface of the transfer roller; the drip tube also sprays cleaning liquid to clean the roller surface of the printing roller, and the printing scraper device scrapes the roller surface of the printing roller, so that the cleaning can be faster, thereby quickly switching the color of the printing.

[0016] Preferably, the cleaning scraper device and the printing scraper device have the same structure, and the contact area and contact force between the scraper assembly and the roller surface of the transfer roller and the roller surface of the printing roller are changed by adjusting the swing angle of the scraper assembly.

[0017] After adopting the above technical scheme, the effect of the present invention is: in the coating and printing method, the coating process can be realized by disassembling the transfer roller and changing the position of the first bracket; or by disassembling the coating roller and replacing it with a printing roller, and then using the paint dripping method to accurately control the amount of paint, thereby achieving clear printing. The coating and printing process can quickly switch processes, saving time and equipment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0019] Figure 1 is a schematic diagram of a printing process according to an embodiment of the present invention;

[0020] Figure 2 is a schematic diagram of a coating process according to an embodiment of the present invention;

[0021] Figure 3 Figure 1 It is a front view of a coating and printing machine for implementing the method of the present invention;

[0022] Figure 4 yes Figure 3 An enlarged schematic diagram at A;

[0023] Figure 5 is a side view of a coating printing machine for implementing the method of the present invention;

[0024] Figure 6 It is a structural schematic diagram of the components on the first bracket, the second bracket, and the main bracket;

[0025] Figure 7 It is a structural diagram of the paint tray lifting mechanism;

[0026] Figure 8 It is a structural schematic diagram of a printing scraper device;

[0027] In the attached drawings: 1, frame; 2, mounting seat; 3, steering roller; 4, backing roller; 5, backing roller seat; 6, backing roller position adjustment device; 7, transfer roller; 8, coating roller; 81, coating roller seat; 9, thickness roller; 10, pick-up roller; 101, pick-up roller seat; 11, first bracket 1; 12, second bracket; 13, thickness roller bracket; 14, first position adjustment device; 15, second position adjustment device; 16, third position adjustment Device; 17. Main bracket; 18. Main linear power device; 19. Paint tray; 20. Worm; 21. Operating handwheel; 22. Worm gear; 23. Rack; 24. Transmission gear; 25. Printing scraper device; 251. Scraper seat; 252. Scraper fixing shaft; 253. Scraper assembly; 254. Scraper control handwheel; 255. Dropper; 26. Cleaning scraper device; 27. Pick-up roller height adjustment mechanism; 28. Limit rod. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below through specific examples.

[0029] like Figure 1 and Figure 2 As shown, a coating and printing method for a plate or coil comprises the following steps:

[0030] S1. Equipment preparation:

[0031] Provide a coating and printing machine for plates or coils, the specific structure is as follows Figures 3 to 8As shown, it includes a frame 1, on which a steering roller 3 and a backing roller 4 are rotatably mounted, and the coating printing machine also includes a first bracket 11 slidably mounted on the frame 1 and located outside the mounting seat 2 of the backing roller 4, and a first position adjustment device 14 for driving the first bracket 11 to approach or move away from the backing roller 4 is provided between the frame 1 and the first bracket 11, a transfer roller 7 is detachably rotatably mounted on the first bracket 11, a second bracket 12 is slidably mounted on the first bracket 11, and a coating roller 8 is detachably rotatably mounted on the second bracket 12, a second position adjustment device 15 for driving the second bracket 12 to slide is provided on the first bracket 11, and a pick-up roller 10 is also rotatably mounted on the second bracket 12, and the pick-up roller 10 is located below the coating roller 8 , a paint tray 19 is arranged below the pick-up roller 10 on the frame 1, and paint is contained in the paint tray 19, and the roller surface of the pick-up roller 10 is partially immersed in the paint; a thickness-fixing roller frame 13 is slidably mounted on the second bracket 12, and a third position adjustment device 16 for driving the thickness-fixing roller frame 13 to slide is installed on the second bracket 12, and a thickness-fixing roller 9 is rotatably arranged on the thickness-fixing roller frame 13, and the pick-up roller 10 and the thickness-fixing roller 9 are both in contact with the coating roller 8, and the sliding direction of the thickness-fixing roller frame 13 and the second bracket 12 is the same as the sliding direction of the first bracket 11, and a dropper 255 and a printing scraper device 25 used in printing but not in coating are also installed on the second bracket 12 above the coating roller 8, and the dropper 255 is connected to the liquid supply system;

[0032] S2, the plate or coil passes through the steering roller 3 and the backing roller 4 in turn during the operation; when it is necessary to enter the printing process, it enters step S4; when it is necessary to enter the coating process, it enters step S3;

[0033] S3. Coating process

[0034] The transfer roller 7 is removed, and the coating printing machine is adjusted. The coating roller 8 is moved closer to the backing roller 4 by using the first position adjustment device 14 and the second position adjustment device 15 and finally squeezed with the surface of the plate or coil. The pick-up roller 10 is immersed in the paint in the paint tray 19, and the third position adjustment device 16 drives the thickness setting roller 9 to contact with the coating roller 8; wherein the printing scraper device 25 is separated from the coating roller 8; the equipment is started, and the pick-up roller 10 picks up the paint in the paint tray 19 and transfers the paint to the coating roller 8. The coating roller 8 rotates against the running direction of the plate or coil and first contacts with the thickness setting roller 9 to set the thickness of the paint film adhering to the surface of the coating roller 8, and then is coated on the surface of the plate or coil against the running direction of the plate or coil;

[0035] S4. Printing process

[0036] The coating roller 8 is disassembled and the printing roller is replaced; the coating printing machine is adjusted so that the pick-up roller 10 is not immersed in the paint, and the adjustment method of the pick-up roller 10 not being immersed in the paint in step S4 is: raising the height of the pick-up roller 10 and / or lowering the height of the paint tray 19.

[0037] The thickness-fixing roller 9 is driven away from the printing roller by the third position adjusting device 16; the liquid supply system drops the paint onto the surface of the printing roller through the dripping tube 255, and then the printing scraper device 25 is used to scrape the surface of the printing roller to form a paint film of a specified thickness. The paint film on the printing roller contacts the transfer roller 7 and transfers the paint film to the transfer roller 7. The transfer roller 7 cooperates with the backing roller 4 to print on the surface of the plate or coil along the traveling direction of the plate or coil.

[0038] Among them, the height of the back roller 4 is adjustable, specifically, the height of the back roller 4 is adjusted by adjusting the height of the back roller seat 5 through a screw lift. When the printing process is adopted, the height of the back roller 4 is adjusted so that the roller surfaces of the back roller 4 and the transfer roller 7 mutually squeeze the surface of the plate or coil; when the coating process is adopted, the height of the back roller 4 is adjusted so that the back roller 4 is higher than the coating roller 8, and the position where the coating roller 8 contacts the plate or coil is on the upstream side of the rotation of the back roller 4. Therefore, during printing, the back roller 4 and the transfer roller 7 squeeze each other, which can provide the squeezing force required for printing and ensure that the pattern is clear during printing; and when coating, the coating roller 8 does not squeeze the back roller 4, so that the paint is directly coated on the surface of the plate or coil, so that the squeezing force will not be too large, thereby ensuring that the thickness of the paint film applied is appropriate.

[0039] Preferably, a main bracket 17 is also slidably mounted on the frame 1, and the sliding direction of the main bracket 17 is the same as the sliding direction of the first bracket 11. A main linear power device 18 that drives the main bracket 17 to slide is installed on the frame 1, and the first bracket 11 is slidably mounted on the main bracket 17. The first position adjustment device 14 is installed between the main bracket 17 and the first bracket 11. The sliding of the main bracket 17 is used to roughly adjust the distance between the coating roller 8 and the plate or coil surface, and then the position of the second bracket 12 is adjusted to fine-tune the contact extrusion force between the coating roller 8 and the plate or coil surface. The main linear power device 18 can be a cylinder or an oil cylinder to achieve automatic position switching.

[0040] The first bracket 11 is provided with a cleaning pipe and a cleaning scraper device 26 for cleaning the transfer roller 7 above the transfer roller 7. When the paint for printing needs to be replaced, the cleaning pipe sprays cleaning liquid to clean the roller surface of the transfer roller 7, and the cleaning scraper device 26 scrapes and washes the roller surface of the transfer roller 7; the dripping tube 255 also sprays cleaning liquid to clean the roller surface of the printing roller, and the printing scraper device 25 scrapes and washes the roller surface of the printing roller, so that it can be cleaned more quickly, thereby quickly switching the color of the printing. The cleaning scraper device 26 has the same structure as the printing scraper device 25, and the contact area and contact force between the scraper assembly and the roller surface of the transfer roller 7 and the roller surface of the printing roller are changed by adjusting the swing angle of the scraper assembly.

[0041] like Figures 3 to 8 As shown, a coating and printing machine for plates or coils, which implements the above-mentioned coating and printing method, includes a frame 1, on which a steering roller 3 and a back roller 4 are rotatably mounted, wherein the back roller 4 is rotatably mounted on a back roller seat 5, and the back roller seat 5 is vertically slidably mounted on a mounting seat 2, and the mounting seat 2 is provided with a back roller position adjustment device 6 for adjusting the vertical position of the back roller seat 5, wherein the back roller position adjustment device 6 adopts a screw lift, and a hand wheel is fixed on the operating screw of the screw lift, and the height of the back roller 4 can be adjusted manually. Of course, the back roller position adjustment device 6 can also adopt a motor and a screw lift to achieve height adjustment.

[0042] The coating and printing machine also includes a first bracket 11 slidably mounted on the frame 1 and located outside the mounting seat 2 of the backing roller 4. A first position adjustment device 14 for driving the first bracket 11 to approach or move away from the backing roller 4 is provided between the frame 1 and the first bracket 11. Since the backing roller 4 has a certain length in this embodiment, the number of the first brackets 11 is two and they are respectively located outside the mounting seat 2.

[0043] The transfer roller 7 is detachably and rotatably mounted on the first bracket 11, the second bracket 12 is slidably mounted on the first bracket 11, the coating roller 8 is detachably and rotatably mounted on the second bracket 12, the first bracket 11 is provided with a second position adjustment device 15 for driving the second bracket 12 to slide, the second bracket 12 is also rotatably mounted with a pick-up roller 10, the pick-up roller 10 is located below the coating roller 8, a paint tray 19 is provided on the frame 1 below the pick-up roller 10, the paint tray 19 contains paint, and the roller surface of the pick-up roller 10 is partially immersed in the paint; a calibrating roller frame 13 is slidably mounted on the second bracket 12, a third position adjustment device 16 for driving the calibrating roller frame 13 to slide is installed on the second bracket 12, a calibrating roller 9 is rotatably mounted on the calibrating roller frame 13, the pick-up roller 10 and the calibrating roller 9 are both in contact with the coating roller 8, and the sliding direction of the calibrating roller frame 13 and the second bracket 12 is the same as the sliding direction of the first bracket 11.

[0044] The first position regulating device 14 , the second position regulating device 15 and the third position regulating device 16 can be controlled manually by a screw-nut mechanism or by a motor.

[0045] A dropper 255 and a printing scraper device 25 used during printing but not during coating are also installed on the second bracket 12 above the coating roller 8. The dropper 255 is connected to the liquid supply system.

[0046] like Figure 5 and Figure 8 As shown, a coating roller seat 81 is fixedly mounted on the second bracket 12, and the coating roller 8 is rotatably mounted on the coating roller seat 81. The printing scraper device 25 includes a scraper seat 251 fixed on the coating roller seat 81, and a scraper fixed shaft 252 is rotatably mounted on the scraper seat 251. A scraper assembly 253 is fixed on the scraper fixed shaft 252, and a deflection adjustment device for driving the scraper fixed shaft 252 to deflect is provided on the scraper seat 251, wherein the deflection adjustment device also includes a scraper control hand wheel 254, and the rotating rod of the scraper control hand wheel 254 is perpendicular to the scraper fixed shaft 252. Therefore, a bevel gear transmission or a worm wheel 22 and a worm 20 can be used between the rotating rod of the scraper control hand wheel 254 and the scraper fixed shaft 252 to achieve a 90° transmission.

[0047] A cleaning pipe and a cleaning scraper device 26 for cleaning the transfer roller 7 are arranged on the first bracket 11 above the transfer roller 7. In this embodiment, the cleaning pipe is used to clean the transfer roller 7, and the cleaning scraper device 26 has the same structure as the transfer scraper device.

[0048] In this embodiment, either the printing roller or the coating roller 8 is actually installed on the second bracket 12 .

[0049] like Figure 6 and Figure 7 As shown, the paint tray 19 is fixedly mounted on the paint tray 19 lifting seat, and the paint tray 19 lifting seat is vertically slidably mounted on the paint tray 19 base, and the paint tray 19 base is fixed on the frame 1, and an operating hand wheel 21 is rotatably mounted on the base of the paint tray 19, and a worm 20 is fixedly mounted on the axle of the operating hand wheel 21, and the worm 20 is matched with a worm wheel 22 rotatably mounted on the base of the paint tray 19, and a transmission gear 24 is installed on the worm wheel 22 shaft of the worm wheel 22, and a rack 23 matched with the transmission gear 24 is provided on the paint tray 19 lifting seat.

[0050] like Figure 5 and Figure 6 As shown, a main bracket 17 is also slidably mounted on the frame 1, and the sliding direction of the main bracket 17 is the same as the sliding direction of the first bracket 11. A main linear power device 18 for driving the main bracket 17 to slide is installed on the frame 1, and the first bracket 11 is slidably mounted on the main bracket 17. The first position adjustment device 14 is installed between the main bracket 17 and the first bracket 11. In this embodiment, the main linear power device 18 is driven by a cylinder or an oil cylinder.

[0051] like Figure 5 and Figure 6 As shown, the pickup roller 10 is rotatably mounted on the pickup roller seat 101, and the pickup roller seat 101 is vertically lifted and slidably mounted on the second bracket 12. The first bracket 11 is provided with a pickup roller height adjustment mechanism 27 for adjusting the height of the pickup roller seat 101.

[0052] The pick-up roller seat 101 is also fixedly mounted with a limit device that contacts and cooperates with the bottom of the coating roller seat 81. The limit device includes a fixing bolt fixed to the top of the pick-up roller seat 101, and a vertical limit rod 28 is installed on the inner thread of the fixing bolt, and the top of the limit rod 28 contacts and cooperates with the bottom of the coating roller seat 81. By rotating the limit rod 28, the position of the top of the limit rod 28 can be adjusted, thereby adjusting the limit at different positions. The pick-up roller height adjustment mechanism 27 is also implemented by a screw lift.

[0053] The gas circuit system, motor and other actuators, gear transmission mechanism, and screw nut mechanism mentioned in this embodiment are all conventional technologies at present. The specific structure and principle of the cylinder, motor and other transmission mechanisms and other designs are disclosed in detail in the "Mechanical Design Manual Fifth Edition" printed in Beijing in April 2008, the fifth edition and the twenty-eighth edition, which belongs to the prior art and its structure is clear. The modern practical pneumatic technology 3rd edition SMC training textbook published by the Machinery Industry Press on August 1, 2008 discloses vacuum components, gas circuits and program control in detail, indicating that the gas circuit structure in this embodiment is also an existing technology, which is clear. The book "Motor Drive and Speed ​​Regulation" published by the Chemical Industry Press on July 1, 2015 also introduces the control of the motor and the travel switch in detail, so the circuit and gas circuit connection are clear. The above-mentioned embodiments are only descriptions of the preferred implementation of the present invention, and are not used as limitations on the scope of the present invention. On the basis of not departing from the design spirit of the present invention, various deformations and modifications made to the technical solution of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A coating and printing method for a plate or coil, characterized in that: The following steps are involved: S1. Equipment preparation: A coating and printing machine for plates or coils is provided, comprising a frame, on which a steering roller and a backing roller are rotatably mounted, the coating and printing machine also comprises a first bracket slidably mounted on the frame and located outside a mounting seat for the backing roller, a first position adjustment device for driving the first bracket to approach or move away from the backing roller is arranged between the frame and the first bracket, a transfer roller is detachably and rotatably mounted on the first bracket, a second bracket is slidably mounted on the first bracket, a coating roller is detachably and rotatably mounted on the second bracket, a second position adjustment device for driving the second bracket to slide is arranged on the first bracket, a pick-up roller is also rotatably mounted on the second bracket, and the pick-up roller is located Below the coating roller, a paint tray is provided on the frame below the pick-up roller, the paint tray contains paint, and the roller surface of the pick-up roller is partially immersed in the paint; a thickness-fixing roller frame is slidably mounted on the second bracket, a third position adjustment device for driving the thickness-fixing roller frame to slide is mounted on the second bracket, a thickness-fixing roller is rotatably mounted on the thickness-fixing roller frame, the pick-up roller and the thickness-fixing roller are both in contact with the coating roller, the sliding direction of the thickness-fixing roller frame and the second bracket is the same as the sliding direction of the first bracket, a dropper and a printing scraper device used in printing but not in coating are also mounted on the second bracket above the coating roller, and the dropper is connected to a liquid supply system; S2, the plate or coil passes through the steering roller and the backing roller in sequence during the operation; when the coating process is required, it goes to step S3; When it is necessary to enter the printing process, proceed to step S4; S3. Coating process The transfer roller is removed, and the coating printing machine is adjusted. The coating roller is moved closer to the backing roller by using the first position adjustment device and the second position adjustment device and finally pressed against the surface of the plate or coil. The pick-up roller is immersed in the paint in the paint tray. The third position adjustment device drives the thickness setting roller to contact the coating roller. The printing scraper device is separated from the coating roller. The equipment is started, and the pick-up roller picks up the paint in the paint tray and transfers the paint to the coating roller. The coating roller rotates against the running direction of the plate or coil and first contacts with the thickness setting roller to set the thickness of the paint film adhering to the surface of the coating roller, and then is coated on the surface of the plate or coil against the running direction of the plate or coil. S4. Printing process The coating roller is disassembled and the printing roller is replaced; the coating printing machine is adjusted so that the pickup roller is not immersed in the paint, and the thickness roller is driven away from the printing roller by the third position adjustment device; the liquid supply system drips the paint onto the surface of the printing roller through the drip tube, and then the printing scraper device is used to scrape the surface of the printing roller to form a paint film of a specified thickness, the paint film on the printing roller contacts the transfer roller and transfers the paint film to the transfer roller, and the transfer roller cooperates with the backing roller to print on the surface of the plate or coil along the traveling direction of the plate or coil.

2. A coating and printing method for a plate or coil as claimed in claim 1, characterized in that: The height of the backing roller is adjustable. When the printing process is adopted, the height of the backing roller is adjusted so that the roller surfaces of the backing roller and the transfer roller press the plate surface or coil surface against each other; when the coating process is adopted, the height of the backing roller is adjusted so that the backing roller is higher than the coating roller, and the position where the coating roller contacts the plate or coil is on the upstream side of the rotation of the backing roller.

3. A coating and printing method for a plate or coil as claimed in claim 2, characterized in that: The adjustment method for preventing the pickup roller from being immersed in the paint in step S4 is: raising the height of the pickup roller and / or lowering the height of the paint tray.

4. A coating and printing method for a plate or coil as claimed in claim 3, characterized in that: A main bracket is also slidably mounted on the frame, and the sliding direction of the main bracket is the same as the sliding direction of the first bracket. A main linear power device for driving the main bracket to slide is installed on the frame, and the first bracket is slidably mounted on the main bracket. The first position adjustment device is installed between the main bracket and the first bracket. The sliding of the main bracket is used to roughly adjust the distance between the coating roller and the plate or coil surface, and then the position of the second bracket is adjusted to fine-tune the contact extrusion force between the coating roller and the plate or coil surface.

5. A coating and printing method for a plate or coil as claimed in claim 4, characterized in that: A cleaning pipe and a cleaning scraper device for cleaning the transfer roller are arranged above the transfer roller on the first bracket. When the paint for printing needs to be replaced, the cleaning pipe sprays cleaning liquid to clean the roller surface of the transfer roller, and the cleaning scraper device scrapes the roller surface of the transfer roller; the dripping pipe also sprays cleaning liquid to clean the roller surface of the printing roller, and the printing scraper device scrapes the roller surface of the printing roller.

6. A coating and printing method for a plate or coil as claimed in claim 5, characterized in that: The cleaning scraper device and the printing scraper device have the same structure. The contact area and contact force between the scraper assembly and the roller surface of the transfer roller and the roller surface of the printing roller can be changed by adjusting the swing angle of the scraper assembly.

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