A printing device for biodegradable shopping bags

Abstract

The utility model relates to biodegradable shopping bag production technology field, concretely is a kind of printing device of biodegradable shopping bag, including rack, solvent supply mechanism being located in the lower side of the inside of rack, transverse drive mechanism being located in the upper side of rack, and version roll cleaning mechanism is connected with the upper side of transverse drive mechanism;The circulating ink supply system includes the ink tank being located in the lower side of the inside of rack, and the ink pump is communicated with the side of ink tank, filter is located on the ink tube section, stirring device is located in the inside of ink tank, and ink return pipe is communicated with the upper side of ink tank;The device can effectively prevent the phenomenon of skinning caused by pigment settlement and solvent evaporation in ink by continuous stirring, ensure concentration uniformity;Impurity can be filtered, ensure ink pure, avoid uneven adhesion of version roll and printing quality problem;Version roll outer surface can also be cleaned, remove residual ink in version roll mesh hole and surface, avoid the printing defect generated thereby and protect version roll surface, prolong its service life.

Description

Technical Field

[0001] This utility model relates to the field of biodegradable shopping bag production technology, specifically to a printing device for biodegradable shopping bags. Background Technology

[0002] Biodegradable shopping bags are produced in nature by microorganisms, generating environmentally friendly carbon dioxide, water, and other biomass. Therefore, biodegradable shopping bags not only meet people's daily shopping needs but also effectively reduce plastic waste. To enable consumers to correctly identify and dispose of biodegradable shopping bags, the appropriate material and degradation symbols are usually labeled during the bag's manufacturing process. The printing of biodegradable shopping bags uses gravure printing, where the entire surface of the printing roller is coated with ink. Then, a special doctor blade removes the ink from the blank areas, leaving only ink in the cells of the image areas. High pressure is then applied to transfer the ink to the surface of a prepared film roll, resulting in the printed biodegradable shopping bag.

[0003] A Chinese patent publication, CN216659274U, describes a continuous roll biodegradable shopping bag production device. While it addresses the issue of insufficient printing contact caused by vibration and airflow deviation of the roll material through a flattening mechanism on both sides of the printing roller, the following problems still exist: First, during actual printing, ink is prone to pigment layering and solvent evaporation during storage, and impurities are easily introduced during transport, leading to uneven ink adhesion on the printing roller surface. This, in turn, causes quality problems such as inconsistent color of the printed pattern on the shopping bag roll and clogging of the printing roller cells. Second, after long-term use, dried ink is easily left on the outer wall of the printing roller and inside the cells, which not only causes blurred edges and discolored stains in subsequent printed patterns, but may also scratch the surface of the printing roller, damage the integrity of the cells, and shorten the service life of the printing roller. Utility Model Content

[0004] The purpose of this invention is to provide a printing device for biodegradable shopping bags, which solves the problems of existing devices where ink is prone to separation and evaporation during storage, easily mixed with impurities during transportation, resulting in uneven adhesion of the printing roller, causing inconsistent pattern colors, and clogging of the printing cells; and where dried ink residue remains on the printing roller after long-term use, affecting the printing effect, damaging the printing roller, and shortening its lifespan.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a printing device for biodegradable shopping bags, comprising a frame, an ink tank disposed on the upper side of the frame, upright plates disposed on the upper side of the frame and respectively located on both sides of the ink tank, an impression roller rotatably connected between the two upright plates and arranged sequentially from top to bottom, a printing roller with printing cells on its outer wall, a first motor disposed on the outer side of one upright plate, and a circulating ink supply system disposed on the lower side inside the frame for supplying ink to the ink tank, wherein the output end of the first motor is connected to one end of the printing roller, and the bottom of the printing roller is immersed in the ink in the ink tank to a depth of 1 / 4-1 / 3 of the diameter of the printing roller; further comprising a solvent supply mechanism disposed on the lower side inside the frame and spaced apart from the circulating ink supply system. The system includes a transverse drive mechanism located on the upper side of the frame and spaced apart from the ink tank, and a printing roller cleaning mechanism connected to the upper side of the transverse drive mechanism. The solvent supply mechanism supplies cleaning solvent to the printing roller cleaning mechanism, which acts on the outer surface of the printing roller. The circulating ink supply system includes an ink storage tank located on the lower side inside the frame, an ink pump connected to one side of the ink storage tank, an ink supply pipe connected to the ink pump, a solenoid valve located on the ink supply pipe section and close to the ink tank, a filter located on the ink supply pipe section, a stirring device located inside the ink storage tank, and a return ink pipe connected to the upper side of the ink storage tank. The inlet port of the return ink pipe is connected to one side of the ink tank at two-thirds of its height, and the outlet port of the ink supply pipe is connected to the other side of the ink tank.

[0006] Furthermore, the printing roller cleaning mechanism includes a movable base, two side plates disposed on the movable base near the printing roller and spaced apart along the length of the printing roller, a brush roller rotatably connected between the two side plates, a third motor disposed on the outer wall of one side plate, a spray pipe with one end connected to the inner wall of one side plate, multiple nozzles communicating with the outer wall of the spray pipe and located between the two side plates, and a guide plate disposed between the two side plates and below the brush roller; the output end of the third motor is connected to one end of the brush roller; the other end of the spray pipe passes through the other side plate and extends to the outside of the other side plate; the multiple nozzles are equally spaced along the length of the spray pipe and all face the outer wall of the printing roller; the bristles of the brush roller are made of solvent-resistant nylon material.

[0007] Furthermore, the transverse drive mechanism includes two mounting plates arranged horizontally at intervals on the upper side of the frame, a lead screw rotatably connected between the two mounting plates, a second motor located on the outside of one mounting plate, two slide rails located on the upper side of the frame and between the two mounting plates, and sliders slidably engaged with the slide rails; both sliders are connected to the lower side of the movable seat; the movable seat is threadedly engaged with the lead screw; and the output end of the second motor is connected to one end of the lead screw.

[0008] Furthermore, a mounting bracket is provided on the side of the ink trough that is against the movable seat, and a doctor blade that fits tightly against the outer wall of the printing roller is installed inside the mounting bracket; the angle between the printing roller and the doctor blade is 60°-65°; the doctor blade is made of tungsten steel.

[0009] Furthermore, the solvent supply mechanism includes a solvent tank located on the lower side inside the frame, a solvent pump connected to one side of the solvent tank, a solvent delivery pipe connected to the solvent pump, and a flexible hose connected to one end of the solvent delivery pipe; the outlet port of the flexible hose is connected to the inlet port of the spray pipe.

[0010] Furthermore, the stirring device includes a fourth motor located on the upper side of the ink storage tank, a stirring shaft connected to the output end of the fourth motor and located inside the ink storage tank, and a three-bladed propeller connected to the lower end of the stirring shaft.

[0011] Furthermore, a PLC controller and an audible and visual alarm are installed at intervals on one side of the frame; a differential pressure sensor is installed on the section of the ink supply tube located on the filter outlet side; a limit switch is installed on the side of the ink tank near the moving seat to limit the movement limit position of the printing roller cleaning mechanism; the limit switch, differential pressure sensor, audible and visual alarm, fourth motor, second motor, solvent pump, third motor, first motor, solenoid valve and ink pump are all electrically connected to the PLC controller.

[0012] Furthermore, a drain pipe is connected to one bottom side of the ink tank; both the return ink pipe and the drain pipe are equipped with manual ball valves near the ink tank.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows: This invention relates to a printing apparatus for biodegradable shopping bags. In terms of ink supply, the stirring device inside the ink tank continuously agitates the ink, preventing pigment layering and solvent evaporation / skinning problems that occur when ink is left to stand in existing equipment, ensuring uniform ink concentration. The filter on the ink supply pipe filters impurities from the ink, ensuring that the ink delivered to the ink tank is pure and free of impurities. This prevents uneven ink adhesion on the printing roller surface and solves quality problems such as inconsistent color of printed patterns and clogging of the printing roller cells. Regarding printing roller maintenance, a solvent supply mechanism, a lateral drive mechanism, and a printing roller cleaning mechanism are used. The solvent supply mechanism delivers cleaning solvent to the printing roller cleaning mechanism, while the lateral drive mechanism moves the brush roller of the cleaning mechanism close to the printing roller, allowing the cleaning mechanism to clean the outer surface of the printing roller and remove dried ink residue from the outer wall and cells. This prevents blurred edges and discoloration in subsequent printing, and also prevents residual ink from scratching the printing roller surface and damaging the cell integrity, extending the service life of the printing roller. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the printing device for the biodegradable shopping bag of this utility model; Figure 2 This is a cross-sectional schematic diagram of the printing device for the biodegradable shopping bag of this utility model; Figure 3 This is a system control block diagram of the printing device for the biodegradable shopping bag of this utility model.

[0015] In the diagram: 1. Frame; 2. Vertical plate; 3. Impression roller; 4. Ink tank; 5. Ink trough; 6. Printing roller; 7. Printing roller cleaning mechanism; 8. PLC controller; 9. First motor; 10. Solvent tank; 11. Solvent pump; 12. Solvent delivery pipe; 13. Hose; 14. Spray pipe; 15. Nozzle; 16. Mounting plate; 17. Second motor; 18. Lead screw; 19. Moving base; 20. Side plate; 21. Brush roller; 22. Third motor; 23. Guide plate; 24. Limit switch; 25. Ink pump; 26. Ink supply pipe; 27. Filter; 28. Differential pressure sensor; 29. ​​Ink return pipe; 30. Drain pipe; 31. Valve; 32. Mounting bracket; 33. Doctor blade; 34. Fourth motor; 35. Stirring shaft; 36. Three-blade propeller; 37. Audible and visual alarm; 38. Solenoid valve. Detailed Implementation

[0016] Please see Figure 1-3 A printing apparatus for biodegradable shopping bags includes a frame 1, an ink tank 5 located on the upper side of the frame 1, upright plates 2 located on the upper side of the frame 1 and respectively on both sides of the ink tank 5, an impression roller 3 rotatably connected between the two upright plates 2 and arranged sequentially from top to bottom, and a printing roller 6 with printing cells on its outer wall, a first motor 9 located on the outside of one of the upright plates 2, and a circulating ink supply system located inside the lower side of the frame 1 for supplying ink to the ink tank 5. The output end of the first motor 9 is connected to one end of the printing roller 6, and the bottom of the printing roller 6 is immersed in the ink tank 5 to a depth of 1 / 4 to 1 / 3 of the diameter of the printing roller 6. It also includes a solvent supply mechanism located inside the lower side of the frame 1 and spaced apart from the circulating ink supply system, and a solvent supply mechanism located on the upper side of the frame 1 and spaced apart from the ink tank 5. The system includes a transverse drive mechanism, a roller cleaning mechanism 7 connected to the upper side of the transverse drive mechanism, and a solvent supply mechanism for supplying cleaning solvent to the roller cleaning mechanism 7. The roller cleaning mechanism 7 acts on the outer surface of the roller 6. The circulating ink supply system includes an ink storage tank 4 located inside the lower side of the frame 1, an ink pump 25 connected to one side of the ink storage tank 4, an ink supply pipe 26 connected to the ink pump 25, a solenoid valve 38 located on the section of the ink supply pipe 26 and close to the ink tank 5, a filter 27 located on the section of the ink supply pipe 26, a stirring device located inside the ink storage tank 4, and a return ink pipe 29 connected to the upper side of the ink storage tank 4. The inlet port of the return ink pipe 29 is connected to one side of the ink tank 5 at two-thirds of its height, and the outlet port of the ink supply pipe 26 is connected to the other side of the ink tank 5.

[0017] Among them, the ink return tube 29 is connected to two-thirds of the height of one side of the ink trough 5, which can return the excess ink in the ink trough 5 to the ink storage box 4 to form a circulation. Combined with the design that the bottom of the printing roller 6 is immersed in the ink trough 5 to a depth of 1 / 4 to 1 / 3 of its diameter, the ink adhesion of the printing roller 6 is further ensured to be stable and the printing consistency is improved.

[0018] This application further proposes that the printing roller cleaning mechanism 7 includes a movable base 19, two side plates 20 fixed to the movable base 19 near the printing roller 6 and spaced apart along the length of the printing roller 6, a brush roller 21 rotatably connected to the inner sides of the two side plates 20 via bearings, a third motor 22 fixedly mounted on the outer wall of one side plate 20 via a motor bracket, a spray pipe 14 connected at one end to the inner wall of one side plate 20, multiple nozzles 15 communicating with the outer wall of the spray pipe 14 and located between the two side plates 20, and a guide plate 23 fixed between the two side plates 20 and located below the brush roller 21 via bolts; the output end of the third motor 22 is coaxially fixedly connected to one end of the brush roller 21 via a coupling; the other end of the spray pipe 14 passes through the other side plate 20 and extends to the outer side of the other side plate 20; the multiple nozzles 15 are equally spaced along the length of the spray pipe 14 and all face the outer wall of the printing roller 6 to ensure that the solvent can be sprayed onto the surface of the printing roller 6; the bristles of the brush roller 21 are made of solvent-resistant nylon material.

[0019] Specifically, the brush roller 21 is made of solvent-resistant nylon, which can withstand the corrosion of cleaning solvents and has good elasticity. It can avoid scratching the printing cells when it is attached to the surface of the printing roller, while effectively wiping away residual ink.

[0020] This application further proposes that the transverse drive mechanism includes two mounting plates 16 horizontally spaced and fixed to the upper side of the frame 1 by bolts; a lead screw 18 rotatably connected between the two mounting plates 16 by bearings; a second motor 17 fixedly mounted on the outside of one mounting plate 16 by a motor mount; two slide rails located on the upper side of the frame 1 and between the two mounting plates 16; and sliders that slide in cooperation with the slide rails; both sliders are bolted to the lower side of the movable seat 19; the movable seat 19 is threadedly engaged with the lead screw 18; and the output end of the second motor 17 is coaxially fixedly connected to one end of the lead screw 18 by a coupling.

[0021] Specifically, the second motor 17 drives the lead screw 18 to rotate, and the screw 18 and the moving seat 19 are connected by a thread, which is converted into the transverse linear motion of the moving seat 19, so as to realize the movement of the printing roller cleaning mechanism 7 closer to the printing roller 6.

[0022] This application further proposes that an mounting bracket 32 ​​is installed on the side of the ink trough 5 that is backed by the movable seat 19 by welding or bolting, with its opening facing the printing roller 6. Inside the mounting bracket 32, a doctor blade 33 that fits tightly against the outer wall of the printing roller 6 is detachably installed by bolts or clips. The angle between the printing roller 6 and the doctor blade 33 is 60°-65°. The doctor blade 33 is made of tungsten steel, with a sharp-angled blade structure, and the length of the doctor blade 33 is the same as the length of the printing roller 6.

[0023] Specifically, the doctor blade 33 is made of tungsten steel, which has extremely high hardness and wear resistance, and can withstand friction with the outer wall of the printing roller 6 for a long time, extending its service life and reducing the maintenance cost of frequent replacements; the sharp-angled blade can scrape away the ink in the blank areas on the surface of the printing roller 6, leaving only the ink in the printing cells, and preventing excess ink from transferring to the film roll and causing printing defects; the 60°-65° angle design takes into account both the scraping force and the protection of the printing roller, ensuring clean scraping while preventing the blade from scratching the outer wall of the printing roller 6 and the printing cells.

[0024] This application further proposes that the solvent supply mechanism includes a solvent storage tank 10 fixedly installed inside the lower side of the frame 1 by bolts, a solvent pump 11 connected to the outlet of the solvent storage tank 10 by a flange seal, a solvent delivery pipe 12 connected to the outlet of the solvent pump 11 by a quick connector, and a hose 13 connected to one end of the solvent delivery pipe 12 by a quick connector; the outlet of the hose 13 is sealed and connected to the inlet of the spray pipe 14.

[0025] Specifically, the hose 13 is made of solvent-resistant corrugated material, which has good flexibility and can adapt to the position change of the printing roller cleaning mechanism 7 as it moves with the transverse drive mechanism, avoiding pipe pulling and breakage and ensuring the continuity of solvent delivery; through the solvent supply mechanism, it can deliver cleaning solvent to the printing roller cleaning mechanism 7 to ensure the cleaning effect of residual ink on the outer wall of the printing roller 6.

[0026] This application further proposes that the stirring device includes a fourth motor 34 fixedly mounted on the upper side of the ink storage tank 4 by bolts, a stirring shaft 35 connected to the output end of the fourth motor 34 by a coupling and located inside the ink storage tank 4, and a three-bladed propeller blade 36 fixedly connected to the lower end of the stirring shaft 35 by a flat key.

[0027] Specifically, the fourth motor 34 drives the stirring shaft 35 to rotate, transmitting power to the three-bladed propeller 36. When the three-bladed propeller 36 rotates, it can stir the ink in the ink storage box 4, breaking the tendency of ink stratification, avoiding pigment particle sedimentation, and ensuring uniform ink concentration. This lays the foundation for the stable adhesion of ink to the printing roller 6 and the uniformity of the printed pattern color during subsequent printing.

[0028] This application further proposes that a PLC controller 8 and an audible and visual alarm 37 are fixedly installed on one side of the frame 1 by bolts; a differential pressure sensor 28 located on the outlet side of the filter 27 is installed on the section of the ink supply tube 26 to monitor the pressure difference between the inlet and outlet of the filter; a limit switch 24 is installed on the side of the ink tank 5 near the moving seat 19 to limit the movement limit position of the printing roller cleaning mechanism 7; the limit switch 24, differential pressure sensor 28, audible and visual alarm 37, fourth motor 34, second motor 17, solvent pump 11, third motor 22, first motor 9, solenoid valve 38 and ink pump 25 are all electrically connected to the PLC controller 8.

[0029] Specifically, the limit switch 24 has its trigger end facing the movable seat 19 to limit the movement limit position of the printing roller cleaning mechanism 7. The differential pressure sensor 28 can monitor the clogging status of the filter 27 in real time. Once the differential pressure exceeds the standard, it transmits a signal to the PLC controller 8, which triggers the audible and visual alarm 37 and simultaneously shuts down the relevant actuators. The limit switch 24 can limit the movement range of the printing roller cleaning mechanism 7 to prevent it from exceeding its travel range and colliding with the ink tank 5. The audible and visual alarm 37 can promptly remind the operator to handle the fault, reducing the risk of production delays due to the fault.

[0030] This application further proposes that a drain pipe 30 is connected to one side bottom of the ink tank 5; and a manual ball valve 31 is provided on both the return ink pipe 29 and the drain pipe 30 near the ink tank 5.

[0031] Specifically, the combination of the ink return pipe 29 and the manual ball valve 31 can cut off the ink return path between the ink tank 5 and the ink storage box 4, preventing the cleaning solvent from mixing with the residual ink during the cleaning process and entering the ink storage box 4 through the ink return pipe 29, thus contaminating the clean ink in the ink storage box; the setting of the drain pipe 30 and the manual ball valve 31 can discharge the residual ink and cleaning waste liquid in the ink tank 5 by manually opening the valve after cleaning.

[0032] Working process and principle: When this biodegradable shopping bag printing device is working, the PLC controller 8 first controls the fourth motor 34 to drive the stirring shaft 35 and the three-bladed propeller 36 to rotate synchronously, so as to uniformly stir the ink in the ink storage tank 4 and prevent the ink from separating. After stirring, the PLC controller 8 instructs the ink pump 25 to start, and delivers the ink in the ink storage tank 4 to the ink tank 5 through the ink supply pipe 26. During this period, the filter 27 on the section of the ink supply pipe 26 filters impurities in the ink. The solenoid valve 38 near the ink tank 5 controls the on and off of the ink delivery according to the PLC command. At the same time, the ink in the ink tank 5 flows back to the ink storage tank 4 through the return ink pipe 29 which is connected to two-thirds of the height of one side of the tank, forming a closed-loop ink circulation to ensure that the liquid level in the ink tank 5 is always stable. If the differential pressure sensor 28 on the ink supply tube 26 detects that the differential pressure at the inlet and outlet of the filter 27 exceeds the standard (determined to be blocked), the PLC controller 8 will immediately trigger the audible and visual alarm 37 to issue an alarm signal, and simultaneously suspend the ink pump 25, the fourth motor 34 and subsequent printing-related mechanisms to prevent impurities from affecting printing quality or damaging the equipment.

[0033] Upon entering the printing stage, the PLC controller 8 starts the first motor 9, driving the printing roller 6 to rotate at a constant speed, with ink adhering to the bottom of the printing roller 6. Subsequently, the tungsten steel doctor blade 33 on the mounting bracket 32 ​​on one side of the ink trough 5 scrapes away the ink from the blank areas on the surface of the printing roller 6, retaining the ink in the printing cells on its outer wall. At the same time, the impression roller 3 and the printing roller 6 rotate together, tightly pressing the biodegradable shopping bag film roll between them. Under pressure, the ink in the cells of the printing roller 6 is transferred to the surface of the film roll, completing a single printing operation.

[0034] When the printing roller 6 needs to be cleaned, the PLC controller 8 first instructs the ink delivery solenoid valve 38 to close and prompts the operator to close the manual ball valve 31 on the ink return pipe 29; then the second motor 17 is started, driving the lead screw 18 to rotate, which drives the moving seat 19, which is threaded with the lead screw 18, to slide smoothly along two parallel slide rails, so that the moving seat 19 gradually approaches the printing roller 6; when the moving seat 19 touches the limit switch 24 next to the ink trough 5, the limit switch 24 feeds a signal back to the PLC controller 8, and the controller immediately instructs the second motor 17 to stop. At this time, the brush roller 21 (solvent-resistant nylon bristles) just forms an elastic fit with the outer wall of the printing roller 6. Next, the PLC controller 8 synchronously starts the solvent pump 11 and the third motor 22. The solvent pump 11 delivers the cleaning solvent in the solvent storage tank 10 to the spray pipe 14 through the solvent delivery pipe 12 and the hose 13, and then sprays the solvent evenly onto the outer wall of the printing roller 6 through multiple nozzles 15. The third motor 22 drives the brush roller 21 to rotate, wiping and cleaning the residual ink on the outer wall of the printing roller 6 and in the printing cells. The waste liquid generated during cleaning is guided by the guide plate 23 into the ink tank 5. After the cleaning operation is completed, the operator opens the manual ball valve 31 on the drain pipe 30 to discharge the cleaning waste liquid and residual impurities in the ink tank 5, thus completing the entire cleaning process.

[0035] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A printing apparatus for biodegradable shopping bags, comprising a frame (1), an ink trough (5) disposed on the upper side of the frame (1), upright plates (2) disposed on the upper side of the frame (1) and located on both sides of the ink trough (5), an impression roller (3) rotatably connected between the two upright plates (2) and distributed sequentially from top to bottom, and a printing roller (6) with printing cells on its outer wall, a first motor (9) disposed on the outer side of one upright plate (2), and a circulating ink supply system disposed on the lower side inside the frame (1) for supplying ink to the ink trough (5), wherein the output end of the first motor (9) is connected to one end of the printing roller (6), and the bottom of the printing roller (6) is immersed in the ink in the ink trough (5) to a depth of 1 / 4-1 / 3 of the diameter of the printing roller (6); characterized in that, It also includes a solvent supply mechanism located on the lower side inside the frame (1) and spaced apart from the circulating ink supply system, a transverse drive mechanism located on the upper side of the frame (1) and spaced apart from the ink tank (5), and a plate roller cleaning mechanism (7) connected to the upper side of the transverse drive mechanism. The solvent supply mechanism is used to supply cleaning solvent to the plate roller cleaning mechanism (7), and the plate roller cleaning mechanism (7) acts on the outer surface of the plate roller (6). The circulating ink supply system includes an ink storage tank (4) located on the lower side inside the frame (1) and a side of the ink storage tank (4). The system includes a connected ink pump (25), an ink supply pipe (26) connected to the ink pump (25), a solenoid valve (38) located on the section of the ink supply pipe (26) and close to the ink tank (5), a filter (27) located on the section of the ink supply pipe (26), a stirring device located inside the ink storage tank (4), and a return ink pipe (29) connected to the upper side of the ink storage tank (4). The inlet port of the return ink pipe (29) is connected to one side of the ink tank (5) at two-thirds of its height, and the outlet port of the ink supply pipe (26) is connected to the other side of the ink tank (5).

2. The printing apparatus for biodegradable shopping bags according to claim 1, characterized in that, The printing roller cleaning mechanism (7) includes a movable base (19), two side plates (20) disposed on the side of the movable base (19) near the printing roller (6) and spaced apart along the length of the printing roller (6), a brush roller (21) rotatably connected between the two side plates (20), a third motor (22) disposed on the outer wall of one side plate (20), a spray pipe (14) with one end connected to the inner wall of one side plate (20), and multiple nozzles (14) communicating with the outer wall of the spray pipe (14) and located between the two side plates (20). 5) A guide plate (23) is located between the two side plates (20) and below the brush roller (21); the output end of the third motor (22) is connected to one end of the brush roller (21); the other end of the spray pipe (14) passes through the other side plate (20) and extends to the outside of the other side plate (20); a plurality of nozzles (15) are arranged at equal intervals along the length of the spray pipe (14) and all face the outer wall of the printing roller (6); the bristles of the brush roller (21) are made of solvent-resistant nylon.

3. The printing apparatus for biodegradable shopping bags according to claim 2, characterized in that, The transverse drive mechanism includes two mounting plates (16) arranged horizontally at intervals on the upper side of the frame (1), a lead screw (18) rotatably connected between the two mounting plates (16), a second motor (17) located outside one of the mounting plates (16), two slide rails located on the upper side of the frame (1) and between the two mounting plates (16), and a slider that slides with the slide rails; both sliders are connected to the lower side of the moving seat (19); the moving seat (19) is threadedly engaged with the lead screw (18); the output end of the second motor (17) is connected to one end of the lead screw (18).

4. The printing apparatus for biodegradable shopping bags according to claim 2, characterized in that, The ink trough (5) is provided with a mounting bracket (32) on one side of the back of the movable seat (19). The mounting bracket (32) is equipped with a doctor blade (33) that fits tightly against the outer wall of the printing roller (6). The angle between the printing roller (6) and the doctor blade (33) is 60°-65°. The doctor blade (33) is made of tungsten steel.

5. The printing apparatus for biodegradable shopping bags according to claim 2, characterized in that, The solvent supply mechanism includes a solvent tank (10) located on the lower side inside the frame (1), a solvent pump (11) connected to one side of the solvent tank (10), a solvent delivery pipe (12) connected to the solvent pump (11), and a flexible hose (13) connected to one end of the solvent delivery pipe (12); the outlet port of the flexible hose (13) is connected to the inlet port of the spray pipe (14).

6. The printing apparatus for biodegradable shopping bags according to claim 5, characterized in that, The stirring device includes a fourth motor (34) located on the upper side of the ink storage box (4), a stirring shaft (35) connected to the output end of the fourth motor (34) and located inside the ink storage box (4), and a three-bladed propeller (36) connected to the lower end of the stirring shaft (35).

7. The printing apparatus for biodegradable shopping bags according to claim 6, characterized in that, A PLC controller (8) and an audible and visual alarm (37) are installed at intervals on one side of the frame (1); a differential pressure sensor (28) is provided on the section of the ink supply tube (26) located on the outlet side of the filter (27); a limit switch (24) is provided on the side of the ink tank (5) near the moving seat (19) to limit the movement limit position of the printing roller cleaning mechanism (7); the limit switch (24), differential pressure sensor (28), audible and visual alarm (37), fourth motor (34), second motor (17), solvent pump (11), third motor (22), first motor (9), solenoid valve (38) and ink pump (25) are all electrically connected to the PLC controller (8).

8. The printing apparatus for biodegradable shopping bags according to claim 1, characterized in that, The bottom of one side of the ink tank (5) is connected to a drain pipe (30); both the return ink pipe (29) and the drain pipe (30) are equipped with manual ball valves (31) near the ink tank (5).

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