Stack-type screen printing machine

Abstract

Disclosed is a stack-type screen printing machine, comprising: a central printing mechanism (10) configured to perform a printing operation on a tray (100), the central printing mechanism having two opposite sides, i.e., a first side and a second side; two positioning frames (20) respectively connected to the first side and the second side of the central printing mechanism; and two material trolleys (30) detachably arranged on the two positioning frames and storing a plurality of trays. When a printing station executes a printing operation, the uppermost tray on the material trolley on the first side is moved by a first conveying mechanism (50) to the central printing mechanism for printing, a tray lifting / lowering mechanism (40) on the first side moves the remaining trays on the material trolley on the first side upward by one layer, and the lowermost tray on the material trolley on the second side is moved by a second conveying mechanism (60) to the lowermost position of the material trolley on the first side. The screen printing machine can complete repeated printing operations on a same printed product in a single printing machine, thereby effectively reducing the site cost and time cost of the printing operations.

Description

Stacked screen printing machine TECHNICAL FIELD

[0001] The present invention relates to a screen printing machine, and in particular to a stacked screen printing machine. BACKGROUND

[0002] The existing screen printing equipment is mostly continuous and in series, and only a small drying oven is left between the printing stations. When the same screen pattern is required for multiple stacked printing on the material, the following situations will occur: (1) The number of screen plates corresponding to the number of stacked printing times needs to be made, and the screen plate itself has errors. It is not easy to control the precision when using different screen plates for stacked printing. (2) Stacked printing often occurs in the gold oil base process for making a printing pattern on the surface of the material. Water-based gold oil needs a long drying time and is not suitable for using infrared heating devices for fast drying. The drying oven of the existing automatic screen printing machine often cannot dry it normally. (3) The product often has different stacked printing process sequences. When using the existing automatic screen printing machine for production, each printing station can basically only print once and then move down to the oven for drying before printing again at the next station. Because the number of printing stations required will be based on the total number of stacked printing times of each process, a large number of printing stations need to be occupied. Therefore, how to provide a single machine modular printing machine that can perform repeated stacked printing through single machine printing is one of the problems that need to be solved by the practitioners and researchers in the printing industry. SUMMARY

[0003] The present invention aims to provide a stacked screen printing machine that can complete the repeated printing operation of the same printed matter in a single printing machine.

[0004] To achieve the above-mentioned invention purposes, the present application provides a stacked screen printing machine, which comprises: a central printing mechanism for performing printing operation on a carrier disc; the central printing mechanism has a first side and a second side on opposite sides; two positioning frames are respectively connected to the first side and the second side of the central printing mechanism; two material trolleys are movably arranged in the two positioning frames of the first side and the second side; each material trolley has a plurality of placement layers arranged in an upper and lower interval for placing a plurality of carrier discs; a first conveying mechanism is movably arranged on the top of the central printing mechanism, and both ends correspond to the two placement layers on the uppermost of the two material trolleys; a second conveying mechanism is movably arranged on the bottom of the central printing mechanism, and both ends correspond to the two placement layers on the lowermost of the two material trolleys; and two carrier disc lifting mechanisms are respectively arranged in the two positioning frames in a lifting manner for being controlled to move the carrier discs on the material trolley in the positioning frame up and down; when performing printing operation, the carrier disc on the uppermost of the material trolley on the first side is moved to the central printing mechanism by the first conveying mechanism for printing, the carrier discs on the material trolley on the first side are moved up by one layer by the carrier disc lifting mechanism on the first side; the carrier disc on the lowermost of the material trolley on the second side is moved to the placement layer on the lowermost of the material trolley on the first side by the second conveying mechanism, and the carrier discs on the material trolley on the second side are moved down by one layer by the carrier disc lifting mechanism on the second side; after the central printing mechanism completes printing, the carrier disc is moved to the placement layer on the uppermost of the material trolley on the second side by the first conveying mechanism, and the carrier discs of the two material trolleys are sequentially and circularly moved until the printing operation of each carrier disc is completed.

[0005] The carrier disc lifting mechanism comprises a plurality of claw groups, a plurality of claw extension and retraction driving units, and a plurality of claw lifting driving units; the claw groups are arranged on opposite sides of the material trolley, each claw group has a plurality of claws corresponding to the placement layers of the material trolley; the claw extension and retraction driving units are respectively connected to the claw groups to drive the claw groups to move towards or away from the material trolley; the claw lifting driving units are respectively connected to the four claw groups to drive the claw groups to move up and down in the vertical direction.

[0006] Each of the opposite sides of the material trolley is provided with two detachable support groups; each support group has a plurality of placement pieces arranged in an upper and lower interval and extending inwardly; the placement layers are formed between the placement pieces, so that when the carrier discs are arranged on the placement layers, the bottoms of the carrier discs are placed on the placement pieces.

[0007] The tray lifting mechanism further comprises two clamping units and two clamping unit driving units. The two clamping units are respectively arranged at the bottom of the positioning frame and correspond to the two connecting portions of the two support groups of the material trolley. The two clamping unit driving units are movably connected to the two clamping units to drive the two clamping units to clamp the two connecting portions and move in the direction approaching or moving away from the material trolley, so that the two support groups can be separated outward from the material trolley or reset inward.

[0008] The positioning frame further comprises a trolley positioning mechanism, which has two handles arranged on opposite sides of the positioning frame and can be moved between an open position and a closed position to limit the material trolley from leaving the positioning frame when the material trolley enters the positioning frame.

[0009] The positioning frame further comprises a trolley lifting mechanism, which has a plurality of positioning claws and a plurality of positioning claw driving units. The positioning claws are movably arranged at the four corners of the positioning frame and correspond to a plurality of positioning holes on the bottom of the material trolley. The positioning claw driving units are movably connected to one end of the positioning claws to drive the positioning claws to extend and retract and ascend, 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 connection, and the material trolley can be lifted to a predetermined height.

[0010] The first conveying mechanism has two tracks, two transmission members, two tray driving units, two hooks and two pushers. The two tracks are arranged on opposite sides of the central printing mechanism. The two transmission members are arranged in the two tracks to be driven by a power source to rotate in a rotating direction. The two tray driving units are movably arranged in the two tracks and connected to the two transmission members to be driven by the two transmission members to move along the two tracks. The two hooks are arranged on one side of the two tray driving units to hook the uppermost tray of the material trolley on the first side and move the tray to the central printing mechanism with the transmission members. The two pushers are arranged on the other side of the two tray driving units opposite the two hooks to push the tray located in the central printing mechanism to the uppermost support layer of the material trolley on the second side.

[0011] The second conveying mechanism has a conveying belt and a conveying belt lifting unit. The conveying belt is driven to rotate in a rotating direction. The conveying belt lifting unit is arranged at the bottom of the conveying belt to drive the conveying belt to move up and down, so that the height of the conveying belt moves to correspond to the lowermost support layer of the two material trolleys.

[0012] The present application further comprises a drying mechanism arranged on one side of the positioning frame to control the drying operation of the trays in the two material trolleys.

[0013] The central printing mechanism comprises a printing seat and a printing seat lifting device; the printing seat is used for placing the carrier disc, and the printing seat lifting device is movably connected to the printing seat and used for driving the printing seat to move along the Z-axis direction to control the height of the printing seat.

[0014] The present application can complete the repeated printing operation of the same printed matter in a single printing machine, effectively reducing the site cost and time cost of the printing operation. BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 is a perspective view of a preferred embodiment of the present application.

[0016] Fig. 2 is an exploded view of the preferred embodiment of the present application.

[0017] Fig. 3 is a perspective view of a material trolley of the preferred embodiment of the present application.

[0018] Fig. 4 is a partial perspective view of the material trolley of the preferred embodiment of the present application after removing the carrier disc.

[0019] Fig. 5 is a partial enlarged view of Fig. 3.

[0020] Fig. 6 is a perspective view of a trolley positioning mechanism of the preferred embodiment of the present application.

[0021] Fig. 7 is a perspective view of a trolley lifting mechanism of the preferred embodiment of the present application.

[0022] Fig. 8 is a perspective view of a carrier disc lifting mechanism of the preferred embodiment of the present application.

[0023] Fig. 9 is a perspective view of a first conveying mechanism of the preferred embodiment of the present application.

[0024] Fig. 10 is an operation schematic view of the preferred embodiment of the present application, showing the path of the carrier disc circulating movement.

[0025] Figs. 11-17 are action schematic views of the preferred embodiment of the present application, showing the process of the carrier disc lifting mechanism controlling the carrier disc in the material trolley to rise.

[0026] Symbol Explanation: (1) Stacked screen printing machine (10) Central printing mechanism (11) Printing stand (12) Printing positioning area (13) Printing stand lifting device (20) Positioning frame (21) Frame (22) Accommodation space (23) Entrance / exit (24) Cart limiting mechanism (240) Handle (25) Cart lifting mechanism (250) Positioning claw (250a) Inclined surface (251) Positioning claw drive unit (26) Mounting slot (27) Ventilation hole (30) Material trolley (31) Cart body (310) Moving wheel (311) Positioning hole (311a) Bearing (32) Support assembly (320) Support body (321) Support plate (322) Connecting part (33) Support layer (40) Carrier lifting mechanism (41) Top claw assembly (410) Top claw (42) Top claw telescopic drive unit (43) Top claw lifting drive unit (44) Gripper unit (45) Gripper drive unit (50) First conveying mechanism (51) Track (52) Transmission component (53) Carrier drive unit (54) Hook (55) Pusher (60) Second conveying mechanism (61) Conveyor belt (62) Conveyor belt lifting unit (70) Drying mechanism (100) Carrier tray Detailed Implementation

[0027] The following description with reference to the accompanying 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 invention. Furthermore, the terms "upper" and "lower," "left" and "right," "front" and "rear," "first" and "second," etc., used in the specification are to clearly indicate the relative positions between elements or mechanisms and are not intended to be limiting.

[0028] Please refer to Figures 1 to 9. A preferred embodiment of the present invention provides a stacked screen printing machine (1), which is 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 means that flat screen printing involves repeated stacking of the same printed material. 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:

[0029] The central printing mechanism (10) includes a printing stand (11) and a printing positioning area (12). The printing stand (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 stand (11). The printing-related technology of the central printing mechanism (10) is similar to that of commercially available large-area printing machines, and its details will not be elaborated here. In particular, the central printing mechanism (10) of the present invention further includes a printing stand lifting device (13), which is movably connected to the printing stand (11) to drive the printing stand (11) to move along the Z-axis to control the height of the printing stand (11). In this embodiment, the printing stand lifting device (13) is controlled by a servo motor. The user can set the screen height to be gradually increased during cyclic printing, and the distance between the screen and the material surface is maintained as the base thickness gradually increases. The central printing unit (10) has a first side and a second side on opposite sides.

[0030] The two positioning frames (20) are respectively located on the first and second sides of the central printing mechanism (10). Each positioning frame (20) has a frame (21), a receiving space (22), and an entrance (23). The frame (21) is a metal assembly, one end of which is connected to the central printing mechanism (10). The receiving space (22) is located inside the frame (21). The entrance (23) is located on the side of the positioning frame (20) away from the central printing mechanism (10) and connects to the receiving space (22).

[0031] The two material trolleys (30) are mobile carriers, detachably mounted in the accommodating space (22) of the two positioning frames (20), and can be driven manually or automatically to enter or leave the two positioning frames (20) through the entrance (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 in the general U-shape. 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 part (322) is provided on the bottom center 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 bracket assembly (32) is normally fixed by a tension spring (not shown) so that the bracket assembly (32) cannot be moved.

[0032] 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) located on opposite sides of the frame (21) of the positioning frame (20) and operable 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.

[0033] 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 located 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 the positioning claws (250) to drive the positioning claws (250) to extend or retract. Each positioning hole (311) has a bearing (311a) above it, 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) can be kept consistent and will not be affected by uneven ground.

[0034] 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 arranged at opposite ends of the material trolley (30) at a certain distance apart. 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-jaw telescopic drive unit (42) is connected to the four-jaw assembly (41) respectively, and is used to drive the four-jaw assembly (41) to move in a direction closer to or away from the material trolley (30). The four-jaw lifting drive unit (43) is connected to the four-jaw assembly (41) respectively, and is used to drive the four-jaw assembly (41) to move up and down in the vertical direction. The two-jaw gripper 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), and is used to grip the connecting parts by being driven by the gripper drive unit (45), and can be further driven by the gripper drive unit (45) to move in a direction closer to or away from the material trolley (30), so that the support assembly (32) can be separated from or reset from the material trolley (30).

[0035] 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 plate 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). The 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). The 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 support 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 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).

[0036] The second conveying mechanism (60) is located at the bottom of the central printing mechanism (10), with its two ends corresponding to the two lowest supporting layers (33) of the two material trolleys (30), respectively. It is used to controllably move the tray (100) at the lowest point of the material trolley (30) on the second side to the lowest supporting layer (33) of the material trolley (30) on the first side for placement. 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) will be 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) have completed positioning, the conveyor belt lifting unit (62) drives the conveyor belt (61) to rise so that the conveyor belt (61) can receive the bottom tray (100) of the two material trolleys (30).

[0037] 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) connected to the mounting groove (26) on opposite sides. 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.

[0038] Based on the above structural configuration, the stacked screen printing machine (1) provided by the present invention is applied in the following way:

[0039] Please refer 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) located 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 support layer (33) at the bottom of the material trolley (30) on the first side. Then, 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. Next, after the central printing unit (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 trays (100) of the two material trolleys (30) will be moved sequentially N times until the printing operation of each tray (100) is completed, so that the printed matter on the trays (100) can be stacked and printed in a single printing station. Where N is a positive integer greater than 2.

[0040] The following will further explain 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. 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 top 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 support layer (33) of the material trolley (30) and lift the trays (100) upward. Next, as shown in Figure 13, the two-claw drive unit (45) controls the two-claw unit (44) to clamp the two connecting parts of the two-support assembly (32) and move them outward, so that the two-support assembly (32) disengages from the material trolley (30). It is worth noting that since the two-support assembly (32) disengages from the material trolley (30), the trays (100) are no longer supported by the two-support assembly (32), and the two-support assembly (32) will not obstruct the vertical movement of the trays (100). Next, as shown in Figure 14, the lifting drive unit (43) drives the top claw 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 support layer (33). Next, as shown in Figure 15, the two-claw drive unit (45) controls the two-claw 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 downward 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 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 lifting drive unit (43) drives the top claw assembly (41) to move downwards, so that the top claw assembly (41) returns 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, so that the supporting layer (33) on the top of the material trolley (30) on the first side can always maintain a state where the tray (100) can be moved.

[0041] 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 parts of the two support assemblies (32) and move them outward, so that the two support assemblies (32) disengage from the material trolley (30). Then, 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 distance of the trays (100) is approximately the height of the support layer (33). Next, the two-jaw drive unit (45) controls the two-jaw unit (44) to move inward, so that the two support assemblies (32) are reconnected to the material trolley (30). Then, the top jaw extension drive unit (42) drives the top jaw assembly (41) to retract obliquely downward in a direction away from the material trolley (30), so that the top jaws of the top jaw assembly (41) leave the support layer (33) of the material trolley (30) and the trays (100) are once again supported by the support plates (321) of the two support assemblies (32). Finally, the top jaw lifting drive unit (43) drives the top jaw assembly (41) to move upward, so that the top jaw assembly (41) returns 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 been moved down one layer compared to the beginning, so 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 tray.

[0042] 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 printing stations as needed, and the production line can be flexibly adjusted according to the product's production process. For example, time-consuming 3D priming can be distributed across multiple stations, combined with subsequent single-station coloring. This satisfies the needs of more complex or higher-volume printing operations.

[0043] In summary, the stacked screen printing machine provided by this invention offers users a modular, stand-alone printing machine where the carrier trays continuously move up and down in a cyclical motion between the two material carriages and the central printing mechanism (10), thereby enabling repeated stacked printing in a single printing machine. Furthermore, this invention can be combined with the rapidly positioning material carriages to achieve multi-station cascade printing production. The modular design of the stand-alone machine and the material carriages make it easier to handle different printing times and process compositions for products, resulting in more flexible production line arrangements.

Claims

1. A stacked screen printing machine, characterized in that... It comprises: 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 connected to the first side and the second side of the central printing mechanism respectively; two material trolleys movably disposed in the two positioning frames on the first side and the second side respectively, 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 respectively; 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 respectively; and two tray lifting mechanisms movably disposed on the two positioning frames for controlled lifting. The trays on the material trolley located in the positioning frame are moved up and down. When a printing operation is performed, 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 one layer up. 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 one layer down. 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 until the printing operation on each tray is completed.

2. The stacked screen printing machine according to claim 1, characterized in that the tray 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 respective supporting layers of the material trolley; the top claw telescopic drive units are respectively connected to the top claw groups for driving the top claw groups to move in a direction closer to or farther from the material trolley; the top claw lifting drive units are respectively connected to the four top claw groups for driving the top claw groups to move up and down in the vertical direction.

3. The stacked screen printing machine according to claim 1, characterized in that each material trolley has two detachable support groups on opposite sides, each support group having 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.

4. The stacked screen printing machine according to claim 1, characterized in that 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.

5. The stacked screen printing machine according to claim 1, characterized in that: The positioning frame further includes a trolley positioning mechanism with two handles located on opposite sides of the positioning frame and operable to move between an open position and a closed position. This is used to move the material trolley from the open position to the closed position when it enters the positioning frame, thereby preventing the material trolley from leaving the positioning frame.

6. The stacked screen printing machine according to claim 1, characterized in that: The positioning frame further includes a vehicle roof lifting mechanism with 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 correspond to a plurality of positioning holes at the bottom of the material trolley. The positioning claw drive unit is 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 raise the material trolley to a predetermined height.

7. The stacked screen printing machine according to claim 1, characterized in that the first conveying mechanism has two tracks, two transmission components, 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 components are respectively disposed in the two tracks for being 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 components for being driven by the two transmission components to move along the two tracks, the two hooks are disposed on one side of the two tray drive units for hooking the tray at the top of the material trolley on the first side and moving the tray to the central printing mechanism with the transmission component, and the two pushers are disposed on the other side of the two tray drive units opposite to the two hooks for pushing the tray located in the central printing mechanism to the support layer at the top of the material trolley on the second side.

8. The stacked screen printing machine according to claim 1, characterized in that 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, and the conveyor belt lifting unit is disposed at the bottom of the conveyor belt to drive the conveyor belt to move up and down, so that the height of the conveyor belt moves to the supporting layer corresponding to the lowest layer of the two material trolleys.

9. The stacked screen printing machine according to claim 1, further comprising a drying mechanism disposed on one side of the positioning frame for controlled drying of the trays in the two material trolleys.

10. The stacked screen printing machine according to claim 1, characterized in that: The central printing unit 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.

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