Stacking type screen printing machine

Abstract

A stacking type screen printing machine comprises: A central printing assembly, configured to perform printing operations on a tray, with a first side and a second side on opposite ends; Two positioning racks, respectively connected to the first side and the second side of the central printing assembly; and two material trolleys, detachably mounted on the two positioning racks, each storing multiple trays. During the printing operation: the top tray of the material trolley on the first side is moved to the central printing mechanism for printing by a first transfer mechanism. A tray lifting mechanism on the first side moves the remaining trays on the material trolley upward by one level. The bottom tray of the material trolley on the second side is transferred to the bottom of the material trolley on the first side by a second transfer mechanism. A tray lifting mechanism on the second side moves the remaining trays on the material trolley downward by one level. After the central printing mechanism completes the printing process, the tray is moved by the first transfer mechanism to the top placement layer of the material trolley on the second side. The trays on the two material trolleys circulate sequentially until the stackable printing operation for all trays is completed.

Description

[Technical Field]

[0001] This invention relates to screen printing machines, and in particular to a stacked screen printing machine that can complete repeated printing operations on the same printed matter in a single printing press. [Previous Technology]

[0002] Note that most existing screen printing equipment is continuous series type, with only a small drying oven between printing stations. When multiple stacks of materials need to be printed with the same screen pattern, the following situation will occur:

[0003] (a) The number of screens required for stacking printing is required. Screen production itself has errors. Using different screens for stacking printing makes it difficult to control the accuracy.

[0004] (ii) Stacking printing often occurs in the process of applying gold oil as a base for printing graphics on the surface of materials. Water-based gold oil requires a long drying time and is not suitable for rapid drying using heating devices such as infrared rays. The drying ovens of existing automatic screen printing machines often cannot dry it properly.

[0005] (iii) Products often consist of processes with different stacked printing times. When using the current automatic screen printing machine for production, each printing station can basically only print once before moving to the oven to dry and then printing again at the next station. Therefore, the number of printing stations required depends on the total number of stacked printing times of each process, which requires a large number of printing stations.

[0006] Therefore, how to provide a modular printing press that can perform repeated stacking printing through single-machine printing is one of the issues that printing industry operators and R&D personnel urgently need to solve. [Summary of the Invention]

[0007] The main objective of this invention is to provide a stacked screen printing machine that can complete repeated printing operations on the same printed material in a single printing machine, effectively reducing the site cost and time cost of printing operations.

[0008] To achieve the above-mentioned objective, the present invention provides a stacked screen printing machine, comprising: a central printing mechanism for printing on a tray; the central printing mechanism having a first side and a second side on opposite sides; two positioning frames respectively connected to the first side and the second side of the central printing mechanism; two material trolleys movably disposed in the two positioning frames on the first side and the second side; each material trolley having a plurality of vertically spaced support layers for placing a plurality of trays; a first conveying mechanism movably disposed at the top of the central printing mechanism, with its two ends corresponding to the two uppermost support layers of the two material trolleys; a second conveying mechanism movably disposed at the bottom of the central printing mechanism, with its two ends corresponding to the two lowermost support layers of the two material trolleys; and two tray lifting mechanisms, respectively lifting... The two positioning frames are configured to control the movement of trays on the material trolleys within them. During printing, the uppermost tray on the first material trolley is moved by the first conveying mechanism to the central printing mechanism for printing. The tray lifting mechanism on the first side moves the remaining trays on the first material trolley upwards one layer. The lowermost tray on the second material trolley is moved by the second conveying mechanism to the lowermost support layer on the first material trolley. The tray lifting mechanism on the second side moves the remaining trays on the second material trolley downwards one layer. After printing by the central printing mechanism is completed, the tray is moved by the first conveying mechanism to the uppermost support layer on the second material trolley. The trays on the two material trolleys move sequentially until the printing operation on each tray is completed.

[0009] In one embodiment, the pallet lifting mechanism includes a plurality of top claw groups, a plurality of top claw telescopic drive units, and a plurality of top claw lifting drive units; the top claw groups are disposed on opposite sides of the material trolley, each top claw group having a plurality of top claws, respectively corresponding to the supporting layers of the material trolley; the top claw telescopic drive units are respectively connected to the top claw groups to drive the top claw groups to move in a direction closer to or away from the material trolley; the top claw lifting drive units are respectively connected to the four top claw groups to drive the top claw groups to move up and down in the vertical direction.

[0010] In one embodiment, each material trolley is provided with two detachable support groups on opposite sides; each support group has a plurality of vertically arranged and inwardly extending support pieces; the support layers are formed between the support pieces, such that when the trays are placed on the support layers, the bottom of the trays rests against the support pieces.

[0011] In one embodiment, the tray lifting mechanism further includes two gripper units and two gripper drive units; the two gripper units are respectively disposed at the bottom of the positioning frame and correspond to the two connecting parts of the two support groups of the material trolley; the two gripper drive units are movably connected to the two gripper units to drive the two gripper units to clamp the two connecting parts and move in a direction close to or away from the material trolley, so that the two support groups can be separated from the material trolley outward or reset inward.

[0012] In one embodiment, the positioning frame further includes a trolley limiting mechanism with two handles disposed on opposite sides of the positioning frame and operable to move between an open position and a closed position, for operation when the material trolley enters the positioning frame to move from the open position to the closed position, so as to restrict the material trolley from leaving the positioning frame.

[0013] In one embodiment, the positioning frame further includes a trolley lifting mechanism having a plurality of positioning claws and a plurality of positioning claw drive units; the positioning claws are movably disposed at the four corners of the positioning frame and corresponding to a plurality of positioning holes at the bottom of the material trolley; the positioning claw drive units are movably connected to one end of the positioning claws to drive the positioning claws to extend, retract, and rise, so that when the material trolley enters the positioning frame, the positioning claws can extend into the positioning holes of the material trolley to form a fixed position, and rise to lift the material trolley to a predetermined height.

[0014] In one embodiment, the first conveying mechanism has two tracks, two transmission members, two tray drive units, two hooks, and two pushers; the two tracks are respectively disposed on opposite sides of the central printing mechanism; the two transmission members are respectively disposed in the two tracks and are driven by a power source to rotate in a rotation direction; the two tray drive units are movably disposed in the two tracks and connected to the two transmission members, and are driven by the two transmission members to move along the two tracks; the two hooks are disposed on one side of the two tray drive units and are used to hook the tray at the top of the material trolley on the first side and move the tray to the central printing mechanism with the transmission member; the two pushers are disposed on the other side of the two tray drive units opposite to the two hooks and are used to push the tray located in the central printing mechanism to the support layer at the top of the material trolley on the second side.

[0015] In one embodiment, the second conveying mechanism has a conveyor belt and a conveyor belt lifting unit; the conveyor belt is driven to rotate in a rotation direction; the conveyor belt lifting unit is located at the bottom of the conveyor belt and is used to drive the conveyor belt to move up and down, so that the height of the conveyor belt moves to the support layer corresponding to the lowest point of the two material trolleys.

[0016] In one embodiment, a drying mechanism is further included, disposed on one side of the positioning frame, for controlled drying of the trays in the two material trolleys.

[0017] In one embodiment, the central printing mechanism includes a printing base and a printing base lifting device; the printing base is used to place the tray, and the printing base lifting device is movably connected to the printing base to drive the printing base to move along the Z-axis direction to control the height of the printing base.

[0018] The following are preferred embodiments based on the purpose, effects and structural configuration disclosed in this invention, and are described in detail with reference to the drawings.

Implementation Method

[0019] The following description with reference to the drawings represents a preferred embodiment of the present invention. It should be understood that these drawings and descriptions are for illustrative purposes only and are not intended to limit the present invention. Furthermore, the terms "upper" and "lower," "left" and "right," "front" and "rear," "first" and "second," etc., used in the specification are used to clearly describe the relative positions between elements or mechanisms and are not intended to be limiting.

[0020] Please refer to Figures 1 to 9. A preferred embodiment of the present invention provides a stacked screen printing machine 1, which is used to provide a modular printing device that can complete stacked printing operations of multiple trays in a single printing station. The stacked printing operation referred to here refers to the repeated stacking and printing of the same printed material multiple times using planar screen printing. The stacked screen printing machine 1 mainly includes a central printing mechanism 10, two positioning frames 20, two material trolleys 30, two tray lifting mechanisms 40, a first conveying mechanism 50, a second conveying mechanism 60, and multiple drying mechanisms 70. Wherein:

[0021] The central printing mechanism 10 includes a printing base 11 and a printing positioning area 12. The printing base 11 is used to perform printing by driving a squeegee assembly to move back and forth above the screen. The printing positioning area 12 provides a support platform for printing and can position the carrier plate in the X and Y axes of the printing base 11. The printing-related technology of the central printing mechanism 10 is similar to that of commercially available large-area printers, and its details will not be elaborated here. In particular, the central printing mechanism 10 of the present invention further includes a printing base lifting device 13, which is movably connected to the printing base 11 to drive the printing base 11 to move along the Z-axis to control the height of the printing base 11. In this embodiment, the printing base lifting device 13 is controlled by a servo motor, and the user can set the screen height to be gradually increased during cyclic printing, and to maintain the distance between the screen and the material surface as the base thickness gradually increases. The central printing mechanism 10 has a first side and a second side on opposite sides.

[0022] The two positioning frames 20 are respectively disposed on the first side and the second side of the central printing mechanism 10. Each positioning frame 20 has a frame 21, a receiving space 22, and an entrance / exit 23. The frame 21 is a metal composite component, one end of which is connected to the central printing mechanism 10. The receiving space 22 is disposed inside the frame 21. The entrance / exit 23 is disposed on the side of the positioning frame 20 away from the central printing mechanism 10 and communicates with the receiving space 22.

[0023] The two material trolleys 30 are mobile carriers, detachably mounted in the receiving space 22 of the two positioning frames 20, and can be manually driven or automatically controlled to enter or leave the two positioning frames 20 through the entrance / exit 23. Specifically, the material trolley 30 has a trolley body 31, two support assemblies 32, and a plurality of supporting layers 33. The bottom side of the trolley body 31 is provided with a plurality of moving wheels 310 and a plurality of positioning holes 311 above the moving wheels 310. The two support assemblies 32 are detachably mounted on opposite sides of the trolley body 31, and each support assembly 32 has a support body 320, a plurality of supporting pieces 321, and a connecting part 322. The support body 320 is a metal frame generally U-shaped. The support pieces 321 are arranged side by side on the support body 320, and the support pieces 321 of the two support groups 32 correspond to each other. The connecting portion 322 is provided on the central bottom side of the support body 320 and extends away from the material trolley 30. The support layers 33 are formed between the support pieces 321 for accommodating a plurality of trays 100. When the trays 100 are accommodated in the support layers 33, the bottom of the trays 100 rests against the support pieces 321. In this embodiment, the user places or adheres the material to be printed onto the tray 100 in advance, and then places the tray 100 into the material trolley 30. The support groups 32 are normally fixed by a tension spring (not shown) so that the support groups 32 cannot be moved.

[0024] The positioning frame 20 further includes a trolley limiting mechanism 24 and a trolley lifting mechanism 25. The trolley limiting mechanism 24 has two handles 240, which are disposed on opposite sides of the frame 21 of the positioning frame 20 and can be operated to move between an open position and a closed position. The two handles 240 are used to move from the open position to the closed position when the material trolley 30 enters the positioning frame 20, thereby blocking the entrance 23 of the positioning frame 20 and fixing the material trolley 30 inside the positioning frame 20 so that it cannot leave the positioning frame 20. In this embodiment, the two handles 240 are two manual handles.

[0025] The trolley lifting mechanism 25 is located at the bottom of the positioning frame 20 and has a plurality of positioning claws 250 and a plurality of positioning claw drive units 251. The positioning claws 250 are movably disposed at the four corners of the positioning frame 20 and correspond to a plurality of positioning holes at the bottom of the material trolley 30, and each positioning claw has a bevel 250a at its front end. The positioning claw drive units 251 are connected to one end of each positioning claw 250 to drive the positioning claw 250 to extend or retract. A bearing 311a is provided above each positioning hole 311, and when the material trolley 30 is on the ground, the height of the bearings 311a is lower than that of the positioning claws 250. When the material trolley 30 enters the positioning frame 20, the trolley lifting mechanism 25 is activated, causing the positioning claws 250 to insert into the positioning holes 311. The inclined surface 250a at the front end of each positioning claw 250 contacts the bearing 311a above the positioning hole 311 and lifts it up, thereby raising the material trolley 30 to a predetermined height and off the ground. In this way, the height of the two material trolleys 30 when positioned in the two positioning frames 20 remains consistent and is not affected by uneven ground.

[0026] The two tray lifting mechanisms 40 are respectively disposed on the two positioning frames 20 and act on the two material trolleys 30 to lift the trays of the material trolleys 30. Specifically, each tray lifting mechanism 40 includes a four-claw assembly 41, a four-claw telescopic drive unit 42, a four-claw lifting drive unit 43, a two-claw unit 44, and a two-claw drive unit 45. Two claw assemblies 41 are respectively provided on opposite sides of the material trolley 30, and the two claw assemblies 41 are positioned at opposite ends of the material trolley 30 at a certain distance. Each claw assembly 41 has a plurality of claws 410 arranged vertically at intervals, and the positions of the claws 410 correspond to the supporting layers 33 of the material trolley 30. The four-claw telescopic drive unit 42 is respectively connected to the four claw assemblies 41 and is used to drive the claw assemblies 41 to move towards or away from the material trolley 30. The four-claw lifting drive unit 43 is connected to the four-claw assembly 41 and is used to drive the four-claw assembly 41 to move up and down in the vertical direction. The two-claw unit 44 is respectively provided at the bottom of the positioning frame 20 and corresponds to the two connecting parts 322 of the two support assemblies 32 of the material trolley 30. It is driven by the claw drive unit 45 to clamp the connecting parts, and can be further driven by the claw drive unit 45 to move in the direction of approaching or moving away from the material trolley 30, so that the support assembly 32 can be separated from or reset from the material trolley 30.

[0027] The first conveying mechanism 50 is located at the top of the central printing mechanism 10, with its two ends corresponding to the two support layers 33 at the top of the two material trolleys 30, respectively. It is controlled to move the tray at the top of the material trolley 30 on the first side to the central printing mechanism 10 for printing, and drives the tray that has been printed in the central printing mechanism 10 to the support layer 33 at the top of the material trolley 30 on the second side for placement. Specifically, the first conveying mechanism 50 has two tracks 51, two transmission components 52, two tray drive units 53, two hooks 54, and two pushers 55. The two tracks 51 are respectively located on opposite sides of the printing base of the central printing mechanism 10. The two transmission components 52 are respectively located in the two tracks 51 and are driven by a power source to rotate in a rotational direction. The two tray drive units 53 are movably mounted on the two tracks 51 and connected to the two transmission members 52, and are driven by the two transmission members 52 to move along the two tracks 51. Two hooks 54 are located on one side of the two tray drive units 53, and are used to hook the tray 100 at the top of the material trolley 30 on the first side, and move the tray to the central printing mechanism 10 with the transmission member 52. Two pushers 55 are located on the other side of the two tray drive units 53 opposite to the two hooks 54, and are used to push the tray located in the central printing mechanism 10 to the supporting layer 33 at the top of the material trolley 30 on the second side. The two-disc drive unit 53 is used to be raised in a controlled manner so that the two hooks 54 or the two pushers 55 can contact the disk 100, and to be lowered when the disk 100 moves to a predetermined position so that the two hooks 54 or the two pushers 55 disengage from the disk 100.

[0028] The second conveying mechanism 60 is located at the bottom of the central printing mechanism 10, with its two ends corresponding to the two supporting layers 33 at the bottom of the two material trolleys 30, respectively. It is used to controllably move the tray 100 at the bottom of the material trolley 30 on the second side to the supporting layer 33 at the bottom of the material trolley 30 on the first side. The second conveying mechanism 60 includes a conveyor belt 61 and a conveyor belt lifting unit 62. In this embodiment, the conveyor belt 61 is a double-rail synchronous PVC belt conveyor. The conveyor belt lifting unit 62 is located at the bottom of the conveyor belt 61 and is used to control the lifting and lowering of the conveyor belt 61. When the two material trolleys 30 on both sides enter the equipment for positioning, the two material trolleys 30 are raised to ensure that their height position remains consistent and is not affected by uneven ground. Therefore, the bottom conveyor is designed to be able to move up and down. When the two material trolleys 30 are not in position, the conveyor belt lifting unit 62 drives the conveyor belt 61 to descend so that the two material trolleys 30 can enter and exit without interference. When the two material trolleys 30 are in position, the conveyor belt lifting unit 62 drives the conveyor belt 61 to rise so that the conveyor belt 61 can receive the lowest tray 100 of the two material trolleys 30.

[0029] The two drying mechanisms 70 are respectively disposed on opposite sides of the two positioning frames 20 for drying the trays 100 in the material trolley 30. Specifically, each positioning frame 20 has a mounting groove 26 and a plurality of ventilation holes 27 on opposite sides communicating with the mounting groove 26. The drying mechanisms 70 are installed in the mounting groove 26 of the positioning frame 20 and heat the mounting groove 26 through the ventilation holes 27. In this embodiment, the drying mechanism 70 can be a hot air blower, an infrared dryer, a filament dryer, or any other device that can heat and dry the trays.

[0030] Based on the above structural configuration, the stacked screen printing machine 1 provided by the present invention is applied in actual operation as follows:

[0031] Referring to Figure 10, when the stacked screen printing machine 1 of the present invention performs a printing operation, the tray 100 at the top of the material trolley 30 on the first side is moved by the first conveying mechanism 50 to the central printing mechanism 10 for printing. Then, the tray lifting mechanism 40 on the first side moves the remaining trays 100 on the material trolley 30 on the first side upwards by one layer. Next, the tray 100 at the bottom of the material trolley 30 on the second side is moved by the second conveying mechanism 60 to the lowermost support layer 33 of the material trolley 30 on the first side. Next, the tray lifting mechanism 40 on the second side moves the remaining trays 100 on the material trolley 30 on the second side downwards by one layer. Finally, after the central printing mechanism 10 completes printing, the tray 100 is moved by the first conveying mechanism 50 to the uppermost support layer 33 of the material trolley 30 on the second side. The two material trolleys 30 will sequentially move the trays 100 N times until the printing operation of each tray 100 is completed, so that the printed materials on the trays 100 can be stacked and printed in a single printing station. Where N is a positive integer greater than 2.

[0032] The detailed mechanism by which the tray lifting mechanism 40 on the first side raises the trays 100 of the material trolley 30 by one layer will be further explained below. As shown in Figure 11, when the tray lifting mechanism 40 on the first side is in standby mode, the top claw extension drive unit 42 is in retracted mode, and the top claw lifting drive unit 43 is in retracted mode. At this time, the trays 100 and the top claw assembly 41 have not yet come into contact. When the uppermost tray 100 of the material trolley 30 is moved to the central printing mechanism 10 by the first conveying mechanism 50, the tray lifting mechanism 40 on the first side begins to operate. First, as shown in Figure 12, the top claw extension drive unit 42 drives the top claw assembly 41 to extend obliquely upward toward the material trolley 30, so that the top claws of the top claw assembly 41 extend into the supporting layer 33 of the material trolley 30 and lift the trays 100 upward. Next, as shown in Figure 13, the two-jaw drive unit 45 controls the two-jaw unit 44 to clamp the two connecting portions of the two support assemblies 32 and move them outward, causing the two support assemblies 32 to detach from the material trolley 30. It is worth noting that since the two support assemblies 32 have detached from the material trolley 30, the trays 100 are no longer supported by the two support assemblies 32, and the two support assemblies 32 do not obstruct the vertical movement of the trays 100. Next, as shown in Figure 14, the top jaw lifting drive unit 43 drives the top jaw assembly 41 to move upward, causing the trays 100 to rise synchronously. The upward movement of the trays 100 is approximately the height of the supporting layer 33. Next, as shown in Figure 15, the two-jaw drive unit 45 controls the two-jaw unit 44 to move inward, causing the two support assemblies 32 to reconnect to the material trolley 30. Next, as shown in Figure 16, the top claw extension drive unit 42 drives the top claw assembly 41 to retract obliquely downwards in a direction away from the material trolley 30, causing the top claws of the top claw assembly 41 to leave the support layer 33 of the material trolley 30 and allowing the trays 100 to be supported again by the support plates 321 of the two support assemblies 32. Finally, as shown in Figure 17, the top claw lifting drive unit 43 drives the top claw assembly 41 to move downwards, returning the top claw assembly 41 to the standby position to complete the tray lifting operation. It should be noted that at this time, the position of each tray 100 has moved one layer upwards compared to the beginning, thereby ensuring that the support layer 33 on the top of the material trolley 30 on the first side always has trays 100 available for movement.

[0033] On the other hand, the detailed mechanism by which the trays 100 of the material trolley 30 on the second side are lowered by the tray lifting mechanism 40 is similar to the lifting mechanism, except that the starting position and moving direction of the top claws are opposite. When the tray lifting mechanism 40 on the second side is in standby mode, the top claw extension drive unit 42 is in the extended state, and the top claw lifting drive unit 43 is in the retracted state, so the initial position of the top claw assembly 41 is higher. When the tray 100 of the central printing mechanism 10 is moved by the first conveying mechanism 50 to the uppermost support layer 33 of the material trolley 30 on the second side, the tray lifting mechanism 40 on the second side begins to operate. First, the top claw extension drive unit 42 drives the top claw assembly 41 to extend obliquely upward toward the material trolley 30, so that the top claws of the top claw assembly 41 extend into the support layer 33 of the material trolley 30 and lift the trays 100 upward. Next, the two-claw drive unit 45 controls the two-claw unit 44 to clamp the two connecting portions of the two support assemblies 32 and move them outward, so that the two support assemblies 32 detach from the material trolley 30. Next, the top claw lifting drive unit 43 drives the top claw assembly 41 to move downward, so that the trays 100 move downward synchronously. The downward movement of the trays 100 is approximately the height of the support layer 33. Next, the two-claw drive unit 45 controls the two-claw unit 44 to move inward, so that the two support assemblies 32 are reconnected to the material trolley 30. Next, the top claw extension drive unit 42 drives the top claw assembly 41 to retract obliquely downwards in a direction away from the material trolley 30, causing the top claws of the top claw assembly 41 to leave the support layer 33 of the material trolley 30 and allowing the trays 100 to be supported again by the support plates 321 of the two support assemblies 32. Finally, the top claw lifting drive unit 43 drives the top claw assembly 41 to move upwards, returning the top claw assembly 41 to the standby position to complete the tray descent operation. It should be noted that at this time, the position of each tray 100 has moved downwards by one layer compared to the beginning, thereby ensuring that the support layer 33 on the top of the material trolley 30 on the second side can always remain in a state that can accommodate the trays.

[0034] It should be added that, in addition to being used as a single printing station, the stacked screen printing machine of the present invention can also be configured as a modular production line design in another preferred embodiment, consisting of multiple printing stations, unloading stations, and material trolleys. These material trolleys can move between the unloading stations and the printing stations as needed, and the production line can be flexibly adjusted according to the product's production process. For example, a three-dimensional priming process requiring a large amount of time can be distributed across multiple stations, combined with subsequent single-station coloring. This satisfies more complex or larger-volume printing operations.

[0035] In summary, the stacked screen printing machine provided by the present invention provides users with a modular printing machine that allows the carrier trays to continuously move up and down in a cyclical manner between the two material carriages and the central printing mechanism 10, thereby enabling repeated stacked printing in a single printing machine. Furthermore, the present invention can also be combined with the rapidly positioning material carriages to achieve multi-station serial printing production. The modular design of the single machine and the material carriages makes it easier to handle different printing times and process compositions for products, resulting in more flexible production line arrangements.

[0036] The above embodiments are merely illustrative of the technology and effects of the present invention and are not intended to limit the present invention. Any person skilled in the art can modify and change the above embodiments without departing from the technical principles and spirit of the present invention. Therefore, the scope of protection of the present invention should be as described in the patent application scope below. [Simplified Explanation of the Diagram]

[0037] Figure 1 is a perspective view of a preferred embodiment of the present invention. Figure 2 is an exploded view of a preferred embodiment of the present invention. Figure 3 is a perspective view of a material trolley of a preferred embodiment of the present invention. Figure 4 is a partial perspective view of a material trolley after the tray has been removed from the material trolley of a preferred embodiment of the present invention. Figure 5 is a partial enlarged view of Figure 3. Figure 6 is a perspective view of a trolley limiting mechanism of a preferred embodiment of the present invention. Figure 7 is a perspective view of a trolley lifting mechanism of a preferred embodiment of the present invention. Figure 8 is a perspective view of a tray lifting mechanism of a preferred embodiment of the present invention. Figure 9 is a perspective view of a first conveying mechanism of a preferred embodiment of the present invention. Figure 10 is an operational schematic diagram of a preferred embodiment of the present invention, showing the path of the tray's cyclical movement. Figures 11-17 are operational schematic diagrams of a preferred embodiment of the present invention, showing the process of the tray lifting mechanism controlling the rise of the tray in the material trolley.

Claims

1. A stacked screen printing machine, comprising: a central printing mechanism for printing on a tray; the central printing mechanism having a first side and a second side opposite to each other; two positioning frames respectively connected to the first side and the second side of the central printing mechanism; two material trolleys movably disposed in the two positioning frames on the first side and the second side; each material trolley having a plurality of vertically spaced support layers for holding a plurality of trays; a first conveying mechanism movably disposed at the top of the central printing mechanism, with its two ends corresponding to the two uppermost support layers of the two material trolleys; a second conveying mechanism movably disposed at the bottom of the central printing mechanism, with its two ends corresponding to the two lowermost support layers of the two material trolleys; and two tray lifting mechanisms movably disposed on the two positioning frames for controlled vertical movement of the trays on the material trolleys located in the positioning frames; wherein... When performing a printing operation, the tray at the top of the material trolley on the first side is moved to the central printing mechanism by the first conveying mechanism for printing; the tray lifting mechanism on the first side moves the remaining trays on the material trolley on the first side upwards by one layer; the tray at the bottom of the material trolley on the second side is moved to the bottom support layer of the material trolley on the first side by the second conveying mechanism; the tray lifting mechanism on the second side moves the remaining trays on the material trolley on the second side downwards by one layer; after the central printing mechanism completes printing, the tray is moved to the top support layer of the material trolley on the second side by the first conveying mechanism; the trays on the two material trolleys move sequentially in a cyclical manner until the printing operation on each tray is completed; wherein the tray lifting mechanism includes a plurality of top claw assemblies, a plurality of top claw telescopic drive units, and a plurality of top claw lifting drive units; The top claw assemblies are located on opposite sides of the material trolley, and each top claw assembly has a plurality of top claws, each corresponding to one of the supporting layers of the material trolley; the top claw extension drive units are respectively connected to the top claw assemblies to drive the top claw assemblies to move toward or away from the material trolley; the top claw lifting drive units are respectively connected to the four top claw assemblies to drive the top claw assemblies to move up and down in the vertical direction.

2. The stacked screen printing machine as claimed in claim 1, wherein each material trolley has two detachable support assemblies on opposite sides; each support assembly has a plurality of vertically arranged and inwardly extending support sheets; the support layers are formed between the support sheets such that when the trays are placed on the support layers, the bottom of the trays rests against the support sheets.

3. The stacked screen printing machine as described in claim 2, wherein the tray lifting mechanism further includes two gripper units and two gripper drive units; the two gripper units are respectively disposed at the bottom of the positioning frame and corresponding to the two connecting parts of the two support groups of the material trolley; the two gripper drive units are movably connected to the two gripper units to drive the two gripper units to clamp the two connecting parts and move in a direction close to or away from the material trolley, so that the two support groups can be separated from the material trolley outward or reset inward.

4. The stacked screen printing machine as described in claim 1, wherein the positioning frame further includes a trolley limiting mechanism having two handles located on opposite sides of the positioning frame and operable to move between an open position and a closed position, for operation when the material trolley enters the positioning frame to move from the open position to the closed position, thereby preventing the material trolley from leaving the positioning frame.

5. The stacked screen printing machine as claimed in claim 1, wherein the positioning frame further includes a carriage lifting mechanism having a plurality of positioning claws and a plurality of positioning claw drive units; the positioning claws are movably disposed at the four corners of the positioning frame and corresponding to a plurality of positioning holes at the bottom of the material carriage; the positioning claw drive units are movably connected to one end of the positioning claws for driving the positioning claws to extend, retract, and rise, so that when the material carriage enters the positioning frame, the positioning claws can extend into the positioning holes of the material carriage to form a fixed position, and rise to lift the material carriage to a predetermined height.

6. The stacked screen printing machine as claimed in claim 1, wherein the first conveying mechanism has two tracks, two transmission members, two tray drive units, two hooks, and two pushers; the two tracks are respectively disposed on opposite sides of the central printing mechanism; the two transmission members are respectively disposed in the two tracks and are driven by a power source to rotate in a rotational direction; the two tray drive units are movably disposed in the two tracks and connected to the two transmission members, and are driven by the two transmission members to move along the two tracks; the two hooks are disposed on one side of the two tray drive units and are used to hook the tray at the top of the material trolley on the first side and move the tray to the central printing mechanism with the transmission member; the two pushers are disposed on the other side of the two tray drive units opposite to the two hooks and are used to push the tray located in the central printing mechanism to the support layer at the top of the material trolley on the second side.

7. The stacked screen printing machine as claimed in claim 1, wherein the second conveying mechanism has a conveyor belt and a conveyor belt lifting unit; the conveyor belt is driven to rotate in a rotational direction; the conveyor belt lifting unit is located at the bottom of the conveyor belt and is used to drive the conveyor belt to move up and down, so that the height of the conveyor belt moves to the support layer corresponding to the lowest layer of the two material trolleys.

8. The stacked screen printing machine as described in claim 1 further includes a drying mechanism located on one side of the positioning frame for controlled drying of the trays in the two material trolleys.

9. The stacked screen printing machine as claimed in claim 1, wherein the central printing mechanism includes a printing stand and a printing stand lifting device; the printing stand is used to place the tray, and the printing stand lifting device is movably connected to the printing stand to move the printing stand along the Z-axis to control the height of the printing stand.