Surface thermal printing equipment

Abstract

The invention belongs to the technical field of printing, and particularly relates to surface thermal printing equipment which comprises a turntable capable of rotating vertically, and a printing position, a feeding position and a discharging position are arranged at the top end, the left end and the right end of the front side of the turntable respectively; a plurality of workpiece fixing positions are sequentially and circumferentially arranged on the rotary disc from the feeding position to the discharging position in the clockwise direction, positioning mechanisms stretching into box workpieces to be fixed are arranged on the workpiece fixing positions, and each positioning mechanism is provided with a plurality of movable blocks which are arranged in the circumferential direction and can do centripetal motion. In the positioning state, the annular structure composed of the multiple movable blocks expands outwards and abuts against the inner side wall of the box body workpiece. In the machining process, the movable block capable of moving towards the inner wall of the box body workpiece abuts against the inner wall of the box body workpiece, then the box body workpiece is fixed from the interior, and more operation space can be provided for printing machining of the outer side wall of the box body workpiece.

Description

Technical Field

[0001] The invention relates to the technical field of printing, in particular to a surface thermal printing device. Background Art

[0002] With the continuous development of industrial technology, printing technology has also changed a lot. Not only limited to screen printing and hot stamping technology, each type of printing technology has its own advantages and disadvantages, and their only disadvantage is that they cannot solve the printing of irregular products, especially special-shaped workpieces, such as cylindrical boxes or square fits. However, the thermal transfer and hot stamping equipment technology of the outer side of special-shaped box prints fills this gap. The irregularity of special-shaped box prints just meets the needs of pad printing.

[0003] However, during the printing process, since the special-shaped box body needs to be fixed, the current conventional practice in the industry is to use a clamping mechanism to clamp the two ends of the box body and rotate it synchronously to facilitate printing operations on the surrounding side walls. However, this method has a disadvantage, that is, the part of the box body workpiece that is clamped will block part of the surface of the workpiece, which will cause printing to not be completed in some cases. Therefore, in order to solve this problem, our company has specially developed a new type of printing equipment. Summary of the invention

[0004] The object of the present invention is to provide a surface thermal printing device to solve the problems raised in the background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a surface thermal printing device, which includes a turntable that can rotate vertically, and the top of the front side of the turntable and the left and right ends are respectively provided with a printing position, a loading position and a unloading position; the turntable is provided with a plurality of workpiece fixing positions circumferentially in sequence from the loading position to the unloading position in a clockwise direction, and the workpiece fixing position is provided with a positioning mechanism that extends into the interior of the box workpiece for fixing, and the positioning mechanism has a plurality of movable blocks that are arranged circumferentially and can perform reciprocating centripetal motion; in the positioned state, the annular structure composed of the plurality of movable blocks expands outward and presses against the inner side wall of the box workpiece.

[0006] The surface thermal printing device described in the present invention, wherein the positioning mechanism includes a positioning shaft arranged along the front-to-back direction and rotatably connected to the turntable, and a positioning seat arranged at the front end of the positioning shaft; the positioning seat is provided with a movable block that can reciprocate along the radial direction of the positioning shaft, and the positioning mechanism also includes an outward expansion module that drives the movable block to reciprocate.

[0007] The surface thermal printing device described in the present invention is characterized in that a movable through hole is axially provided in the positioning shaft and passes through both ends thereof, and an inner cavity connected to the movable through hole is provided in the positioning seat; the outward expansion module includes a movable rod which is axially movably provided in the movable through hole and whose front end extends into the inner cavity, and a reciprocating drive component which drives the movable rod to axially reciprocate; a connecting arm is hinged at the front end of the movable rod, and an end of the connecting arm which is away from the movable rod is hinged to the movable block.

[0008] The surface thermal printing device described in the present invention, wherein the reciprocating drive assembly includes a ring member coaxially movably sleeved on the positioning shaft, a connecting rod connecting the ring member and the movable rod member, and a positioning drive unit that drives the ring member to axially reciprocate; the positioning shaft is provided with a avoidance hole for the movement of the connecting rod, an annular groove is coaxially provided on the outer peripheral side wall of the ring member, and a push rod extending into the annular groove is provided on the movable terminal of the positioning drive unit.

[0009] The surface thermal printing device described in the present invention, wherein the device also includes a hot stamping printing module arranged above the turntable and used to print the box workpiece fixed on the positioning mechanism, a first driving mechanism arranged at the top of the rear side of the turntable and used to drive the positioning mechanism to realize fixed-axis self-rotation, and a clutch transmission mechanism that is activated and transmits the connection between the first driving mechanism and the positioning mechanism when the printed box workpiece moves to the printing position.

[0010] The surface thermal printing device described in the present invention, wherein the clutch transmission mechanism includes a first fitting part arranged at the rear end of the positioning shaft, a second fitting part that can be separated or connected to the first fitting part, and a separation drive module that drives the second fitting part to be connected or separated from the first fitting part; the second fitting part is arranged on the rotating shaft of the first drive mechanism, and the first drive mechanism is arranged on the movable terminal of the separation drive module.

[0011] The surface thermal printing equipment described in the present invention, wherein the equipment also includes a support frame arranged on the front side of the turntable, a workpiece positioning rod arranged on the support frame along the front-to-back direction, and a workpiece positioning plate vertically fixed to the rear end of the workpiece positioning rod; the workpiece positioning rod is longitudinally rotationally connected to the support frame, and in the positioning state, the rear side wall of the workpiece positioning plate is coaxially abutted against the front end of the box workpiece.

[0012] The surface thermal printing device described in the present invention further includes a second driving mechanism for driving the turntable to rotate, the turntable is connected to the output shaft of the second driving mechanism through a driving shaft, and the driving shaft is provided with channels running through both ends thereof.

[0013] The surface thermal printing device of the present invention further comprises a loading mechanism and a unloading mechanism respectively arranged at the loading position and the unloading position.

[0014] The surface thermal printing device of the present invention, wherein the loading mechanism and the unloading mechanism both include a conveyor belt arranged in the left-right direction, and a suction cup module arranged above the front side of the conveyor belt and movable forward and backward; the loading mechanism also includes a transfer table arranged between the conveyor belt and the suction cup module, and a material transfer robot for moving the box workpiece to the transfer table

[0015] Compared with the prior art, the present invention has the following beneficial effects: during processing, the movable block that can move toward the inner wall of the box workpiece is pressed against the inner wall of the box workpiece, thereby achieving fixing of the box workpiece from the inside, thereby providing more operating space for printing processing of the outer wall of the box workpiece. Compared with the traditional clamping scheme that causes the clamping part of the box workpiece to be blocked, resulting in the disadvantage that printing cannot be fully carried out, the present scheme can completely avoid the occurrence of such problems, and the printing effect can be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a structural schematic diagram of the present invention.

[0018] Figure 2 It is a top view of the present invention.

[0019] Figure 3 It is a rear view of the present invention.

[0020] Figure 4 for Figure 3 A magnified view of the local structure.

[0021] Figure 5 It is a front view of the present invention.

[0022] Figure 6 An isolated view of the assembly of the turntable and the positioning mechanism of the present invention.

[0023] Figure 7 for Figure 6 A magnified view of the local structure from the front side.

[0024] Figure 8 for Figure 7 Bottom view of .

[0025] Fig. 9 for Figure 6 Front view of.

[0026] Fig.10 for Fig. 9 AA section view in. DETAILED DESCRIPTION

[0027] The terms "first", "second", "third" and "fourth" etc. in the specification and claims of the present invention and the drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0028] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0029] "Multiple" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the related objects are in an "or" relationship.

[0030] Moreover, the terms "up, down, left, right, upper end, lower end, longitudinal" and the like indicating directions are all based on the posture and position of the device or equipment described in this solution during normal use.

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the following will be described clearly and completely in combination with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are partial embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0032] This embodiment discloses Figures 1 to 10The surface thermal printing device shown includes a vertically rotatable turntable 10, which is specifically circular. A base mounting plate 20 is vertically provided on the rear side of the turntable 10, and the turntable 10 is rotatably connected to the base mounting plate 20 via a hollow rotating shaft (not shown). The top of the front side of the turntable 10 and the left and right ends are respectively provided with a printing position, a loading position and a unloading position; a plurality of workpiece fixing positions are arranged on the turntable 10 in a clockwise direction from the loading position to the unloading position at equal intervals in the circumferential direction, and a positioning mechanism 30 is provided on the workpiece fixing position, which extends into the interior of the box workpiece and fixes it, and the positioning mechanism 30 has a plurality of movable blocks 3a arranged circumferentially and capable of reciprocating centripetal motion; in the positioning state, the annular structure composed of the plurality of movable blocks 3a expands outward and presses against the inner wall of the box workpiece, wherein the outer wall of the movable block 3a can be set to a corresponding shape according to the shape of the inner wall of the box workpiece, if the box workpiece is cylindrical, the outer wall of the movable block 3a is directly set to an arc shape, and if the inner wall of the box workpiece is a prismatic structure, a convex corner can be set on the arc surface to correspond to the recessed portion at the position of the corner of the inner wall of the box workpiece; of course, the arc surface or the convex corner can also be realized by an independent and detachable positioning block 3a1.

[0033] During processing, the movable block 3a that can move toward the inner wall of the box workpiece is pressed against the inner wall of the box workpiece, thereby fixing the box workpiece from the inside, thereby providing more operating space for the printing processing of the outer wall of the box workpiece. Compared with the traditional clamping scheme, which will cause the clamping part of the box workpiece to be blocked and the printing cannot be fully carried out, this scheme can completely avoid the occurrence of such problems and greatly improve the printing effect.

[0034] In this embodiment, the positioning mechanism 30 includes a positioning shaft 31 arranged along the front-back direction and rotatably connected to the turntable 10, and a positioning seat 32 arranged at the front end of the positioning shaft 31; wherein the rear end of the positioning shaft 31 passes through the turntable and is adjacent to the base mounting plate; the positioning seat 32 is provided with a movable block 3a that can reciprocate along the radial direction of the positioning shaft 31. The positioning mechanism 30 also includes an external expansion module 33 that drives the movable block 3a to reciprocate. Specifically, the positioning shaft 31 is coaxially provided with an active through hole 311 that passes through both ends thereof along the axial direction. The positioning seat 32 is provided with an inner cavity 321 that is coaxial and connected with the active through hole 311, and the diameter of the inner cavity 321 is larger than the diameter of the active through hole 311 and is specifically in the shape of a cuboid. The long side of the inner cavity 321 is parallel to the axial direction of the active through hole 311 and is coaxial with the axis of the active through hole 311. The outward expansion module 33 includes a movable rod 331 axially movably disposed in the movable through hole 311 and with its front end extending into the inner cavity 321 . The rear end of the movable rod 331 is cylindrical and slidably fits with the inner wall of the movable through hole 311 to prevent the positioning shaft 31 from shaking.

[0035] Furthermore, the outward expansion module 33 also includes a reciprocating drive assembly 332 for driving the movable rod 331 to reciprocate axially, and a connecting arm 40 is hinged at the front end of the movable rod 331, and one end of the connecting arm 40 facing away from the movable rod 331 is hinged to the movable block 3a, and the hinge axes at both ends of the connecting arm 40 are parallel to each other and perpendicular to the movable rod 331, and a movable hole 3210 is provided on the inner wall of the inner cavity 321 to avoid the connecting arm 40, so as to facilitate extending one end of the connecting arm 40 out of the inner cavity 321 and hinged to the movable block 3a during installation. Among them, in the initial state, one end of the connecting arm 40 hinged to the movable block 3a faces forward, and the other end connected to the positioning shaft 31 faces backward, that is, the angle between the connecting arm 40 and the movable rod 331 is acute, so that when the reciprocating drive assembly 332 drives the movable rod 331 to move forward, the movable block 3a is pushed radially outward by the connecting arm 40 and abuts against the inner wall of the box workpiece, thereby achieving fixation of the box workpiece.

[0036] Among them, the positioning seat 32 is generally arranged in a rectangular shape and its cross-section is square. In order to further ensure the stability of the fixed box workpiece, three movable blocks 3a are generally arranged and are respectively arranged on three adjacent side walls of the positioning seat 32; further, a guide shaft 50 for guiding the movable block 3a is arranged on the positioning seat 32, and each movable block 3a is guided by two guide shafts 50. Specifically, the guide shaft 50 is slidably connected to the positioning seat 32 and is detachably connected to the movable block 3a by bolts. The guiding effect of the guide shaft 50 can make the reciprocating movement of the movable block 3a more stable without deflection.

[0037] In addition, in order to ensure the stability of the movable rod 331 , a guide rail 60 is provided in the inner cavity 321 for axially guiding the front end of the movable rod 331 .

[0038] In this embodiment, the reciprocating drive assembly 332 can be arranged inside the movable through hole 311 or outside the movable through hole 311. If the former setting method is adopted, it is necessary to increase the diameter of the positioning shaft 31 to expand its internal space to meet the installation requirements. In contrast, this scheme gives priority to the latter setting method. This method of installation and driving of the reciprocating drive assembly 332 are more convenient to select.

[0039] Specifically, the reciprocating drive assembly 332 includes a ring 3321 coaxially sleeved on the positioning shaft 31, a connecting rod 3322 connecting the ring 3321 and the movable rod 331, and a positioning drive unit 3323 driving the ring 3321 to reciprocate axially; wherein the positioning drive unit 3323 is a cylinder, and of course it can also be a linear drive module such as a screw motor module or an oil cylinder, the ring 3321 and the movable rod 331 are both detachably connected to the connecting rod 3322 by bolts, and the connecting rod 3322 is provided with multiple and evenly spaced distributions along the circumferential direction of the positioning shaft 31. Further, a avoidance hole 70 for the reciprocating movement of the connecting rod 3322 is provided on the positioning shaft 31, and the avoidance hole 70 is in the shape of a long strip and its length is greater than or equal to the stroke of the movable rod 331 to ensure the normal movement of the movable rod 331.

[0040] Furthermore, an annular groove 80 is coaxially provided on the outer peripheral side wall of the ring member 3321, and a push rod 90 extending into the annular groove 80 is provided on the movable terminal of the positioning drive unit 3323. When the positioning drive unit 3323 is in action, the movable rod 331 can be pushed forward or backward through the cooperation of the push rod 90, the ring member 3321 and the connecting rod 3322, thereby realizing the outward expansion or inward contraction and reset of the annular structure composed of multiple movable blocks 3a. During expansion, the inner wall of the box workpiece can be positioned, and during contraction and reset, the box workpiece can be removed for the next step of processing. Moreover, through the limiting cooperation of the annular groove and the extended push rod 90, the movable rod 331 can be synchronously driven to reciprocate axially while the positioning shaft 31 rotates.

[0041] Specifically, the push rod 90 is U-shaped and its two arms are located on the left and right sides of the positioning shaft 31. The positioning drive unit 3323 is arranged on the lower side of the positioning shaft 31 and the end of its piston rod is connected to the lower end of the push rod 90. Furthermore, in order to reduce the friction between the two ends of the push rod 90 and the inner wall of the annular groove 80, bearings 100 are provided on both arms of the push rod 90. The rotating shaft of the bearing 100 passes through the horizontal diameter of the positioning shaft 31, and the diameter of the bearing 100 is adapted to the width of the annular groove 80. During actual assembly, the width of the bearing 100 and the annular groove 80 has a certain processing error, which can be used to facilitate the relative rolling of the bearing 100 and the ring 3321.

[0042] In this embodiment, the device further includes a hot stamping printing module 110 disposed above the turntable 10 and printing on a box workpiece fixed on the positioning mechanism 30, a first driving mechanism 120 disposed at the top of the rear side of the turntable 10 and used to drive the positioning mechanism 30 to realize fixed-axis self-rotation, and a clutch transmission mechanism 130 that actuates and transmits the connection between the first driving mechanism 120 and the positioning mechanism 30 when the printed box workpiece moves to the printing position; specifically, the clutch transmission mechanism 130 includes a rear end disposed at the positioning shaft 31 The first engaging member 131, the second engaging member 132 which can be separated from or connected to the first engaging member 131, and the separation driving module 133 which drives the second engaging member 132 to be connected to or separated from the first engaging member 131; the second engaging member 132 is coaxially arranged on the rotating shaft of the first driving mechanism 120, and the first driving mechanism 120 is arranged on the movable terminal of the separation driving module; wherein the separation driving module 133 is a cylinder, and of course, it can also be realized by a conventional linear mechanism such as a screw motor or a linear motor, When the separation drive module 133 is in motion, the first drive mechanism 120 and the second engaging member can be driven to move, so that the second engaging member is connected to or separated from the first engaging member; further, the first engaging member 131 can be a shaft member or a plate member with a pin hole, and the second engaging member 132 can be a block member or a plate member or a shaft member with a pin shaft that can be matched with the pin hole. If only one pin hole is provided, its cross section must be non-circular. If multiple pin holes are provided, their shapes are not limited. Of course, the first engaging member 131 and the second engaging member 132 can be connected to each other. Either one of the fittings 132 can be a strong magnet, and the other can be a ferromagnetic object; or either one of the first fitting part 131 and the second fitting part 132 can be an electromagnet, and the other can be a ferromagnetic object; in this scheme, the second fitting part 132 is preferably an electromagnet, and the first fitting part 131 is preferably a ferromagnetic object. When the positioning shaft 31 rotates to the printing position, the first driving mechanism 120 can drive the positioning shaft 31 to rotate by the adsorption cooperation of the electromagnet and the ferromagnetic first fitting part 131.

[0043] Among them, the hot stamping printing module 110 can be implemented using the hot stamping modules commonly used on the market to reduce cost investment and facilitate later after-sales guarantee. Its specific structure includes a roller hot stamping head 111 parallel to the rotation axis of the turntable 10, a hot stamping rotating unit 112 that drives the roller hot stamping head 111 to rotate on a fixed axis, and an XZ two-axis driving module 113 that drives the roller hot stamping head 111 to rise and fall and move left and right, and a hot stamping material belt feeding module 114 arranged on the left and right sides of the roller hot stamping head 111; the hot stamping rotating unit 112 and the roller hot stamping head 111 are both arranged on the movable terminal of the XZ two-axis driving module 113; among them, the hot stamping rotating unit 112 is generally a servo motor, and the X-axis of the XZ two-axis driving module 113 is installed on the base mounting plate 20, and the Z-axis is installed on the movable terminal of the X-axis. On the movable terminal, the hot stamping rotating unit 112 and the roller hot stamping head 111 are specifically arranged on the movable terminal of the Z axis, so that the hot stamping rotating unit 112 and the roller hot stamping head 111 can realize left and right and up and down movement; further, the hot stamping material belt feeding module 114 generally includes two coplanar material trays 1141 opposite to each other on the left and right sides and a roller cylinder 1142 for tightening the material belt, one of the material trays 1141 is used to supply the material belt 400, and the other is used to roll up the waste material belt 500 after hot stamping. The two material trays 1141 can be independently driven by two motors respectively. During printing, the material belt is located between the roller hot stamping head and the box workpiece. When the roller hot stamping head moves down, the material belt is pressed against the outer wall of the box workpiece, and the pattern on the material belt is printed on the box workpiece by heating and pressurizing.

[0044] In this embodiment, the device further includes a support frame 140 arranged on the front side of the turntable 10, and a workpiece positioning rod 150 arranged on the support frame 140 along the front-to-back direction, and a workpiece positioning plate 160 vertically fixed at the rear end of the workpiece positioning rod 150; the workpiece positioning rod 150 is longitudinally rotatably connected to the support frame 140. In the positioned state, the rear side wall of the workpiece positioning plate 160 is coaxially abutted against the front end of the box workpiece to provide necessary support for the front end of the box workpiece during printing to avoid downward deflection when receiving pressure. In order to avoid interfering with the rotation of the turntable 10, a positioning cylinder 170 is also provided on the support frame 140 to drive the workpiece positioning rod 150 to move forward and backward to achieve the fitting and separation of the workpiece positioning plate 160 and the box workpiece.

[0045] In this embodiment, the device also includes a second driving mechanism 180 for driving the turntable 10 to rotate. The turntable 10 is connected to the output shaft of the second driving mechanism 180 through a hollow shaft. A channel running through both ends of the hollow shaft can improve the rigidity of the driving shaft while facilitating the passage of the air pipe of the cylinder on the turntable 10 through the channel, thereby achieving continuous air supply to the cylinder; wherein, the first driving mechanism and the second driving mechanism 180 are both motors, and in order to ensure the stability of the output torque, a corresponding transmission 181 is also connected to the output end of the second driving mechanism 180; wherein, the first driving mechanism and the second driving mechanism are both arranged on the rear side wall of the base mounting plate, and a window for connecting the second mating part with the first mating part is provided at the upper end of the base mounting plate opposite to the printing position.

[0046] In this embodiment, the device further includes a loading mechanism 190 and a unloading mechanism 200 which are respectively arranged at the loading position and the unloading position. Specifically, the loading mechanism 190 and the unloading mechanism 200 both include a conveyor belt 1a arranged in the left-right direction, and a suction cup module 1b which is arranged on the upper front side of the conveyor belt 1a and can move forward and backward; specifically, the suction cup module 1b includes a suction cup body 1b1 for adsorbing the front end surface of the box workpiece, and a linear drive unit 1b2 for driving the suction cup body 1b1 to move forward and backward; the linear drive unit 1b2 can adopt commonly used modules such as a cylinder or a screw motor or a linear motor. When loading and unloading is required, the suction cup body 1b1 is driven by the linear drive unit 1b2 to be adsorbed and fixed to the box workpiece, thereby facilitating the box workpiece to be put on the movable block 3a or removed from the movable block 3a.

[0047] Furthermore, the loading mechanism 190 also includes a transfer table 191 arranged between its conveyor belt 1a and the suction cup module 1b, and a material transfer robot 192 for moving the box workpiece to the transfer table 191; when the turntable 10 rotates into position, the movable block 3a is aligned with the rear end of the transfer table 191, and the material transfer robot 192 moves the box workpiece from the conveyor belt 1a to the transfer table 191 in advance. At this time, the front end surface of the box workpiece is sucked by the suction cup module 1b and put onto the movable block 3a. After it is in place, the suction cup module 1b is reset, and the turntable 10 is started in the next step and the box workpiece on the movable block 3a is moved to the printing station.

[0048] In addition, in order to ensure stable printing quality, a hot air gun 210 for blowing hot air to the box workpiece is provided on the support frame 140 above the transfer table 191. The surface of the box workpiece is heated by the hot air gun 210 to enhance the adhesion between the printed pattern and the surface of the box workpiece. Furthermore, an air collecting hood 220 is provided on the base mounting plate 20. The inlet of the air collecting hood 220 is trumpet-shaped and opposite to the hot air gun 210. The gap between the two can allow the positioning mechanism 30 and the box workpiece to rotate through.

[0049] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A surface thermal printing device, characterized in that: The equipment comprises a turntable which can rotate vertically, wherein a printing position is arranged at the top of the front side of the turntable, and a loading position and a unloading position are arranged at the left and right ends respectively; a plurality of workpiece fixing positions are arranged circumferentially in a clockwise direction from the loading position to the unloading position on the turntable, and a positioning mechanism which extends into the interior of the box workpiece for fixing is arranged on the workpiece fixing position, and the positioning mechanism has a plurality of movable blocks which are arranged circumferentially and can perform reciprocating centripetal motion; in the positioning state, the annular structure composed of the plurality of movable blocks expands outward and presses against the inner side wall of the box workpiece.

2. The surface thermal printing device according to claim 1, characterized in that: The positioning mechanism includes a positioning shaft arranged along the front-to-back direction and rotatably connected to the turntable, and a positioning seat arranged at the front end of the positioning shaft; the positioning seat is provided with a movable block that can reciprocate along the radial direction of the positioning shaft, and the positioning mechanism also includes an outward expansion module that drives the movable block to reciprocate.

3. The surface thermal printing device according to claim 2, characterized in that: The positioning shaft is axially provided with a movable through hole running through both ends thereof, and the positioning seat is provided with an inner cavity connected to the movable through hole; the outward expansion module includes a movable rod which is axially movably arranged in the movable through hole and whose front end extends into the inner cavity, and a reciprocating drive component which drives the movable rod to axially reciprocate; the front end of the movable rod is hinged with a connecting arm, and the end of the connecting arm which is away from the movable rod is hinged to the movable block.

4. The surface thermal printing device according to claim 3, characterized in that: The reciprocating drive assembly includes a ring member coaxially movably sleeved on the positioning shaft, a connecting rod connecting the ring member and the movable rod member, and a positioning drive unit that drives the ring member to axially reciprocate; the positioning shaft is provided with a avoidance hole for the movement of the connecting rod, an annular groove is coaxially provided on the outer peripheral side wall of the ring member, and a push rod extending into the annular groove is provided on the movable terminal of the positioning drive unit.

5. The surface thermal printing device according to claim 2, characterized in that: The device also includes a hot stamping printing module arranged above the turntable and used to print the box workpiece fixed on the positioning mechanism, a first driving mechanism arranged at the top of the rear side of the turntable and used to drive the positioning mechanism to realize fixed-axis self-rotation, and a clutch transmission mechanism that is activated and transmits the connection between the first driving mechanism and the positioning mechanism when the printed box workpiece moves to the printing position.

6. The surface thermal printing device according to claim 5, characterized in that: The clutch transmission mechanism comprises a first engaging member arranged at the rear end of the positioning shaft, a second engaging member which can be separated from or connected to the first engaging member, and a separation driving module which drives the second engaging member to be connected to or separated from the first engaging member; The second engaging member is arranged on the rotating shaft of the first driving mechanism, and the first driving mechanism is arranged on the movable terminal of the separation driving module.

7. The surface thermal printing device according to claim 2, characterized in that: The device also includes a support frame arranged on the front side of the turntable, a workpiece positioning rod arranged on the support frame along the front-to-back direction, and a workpiece positioning plate vertically fixed to the rear end of the workpiece positioning rod; the workpiece positioning rod is longitudinally rotatably connected to the support frame, and in the positioning state, the rear side wall of the workpiece positioning plate is coaxially abutted against the front end of the box workpiece.

8. The surface thermal printing device according to claim 1, characterized in that: The device also includes a second driving mechanism for driving the turntable to rotate. The turntable is connected to the output shaft of the second driving mechanism through a driving shaft. The driving shaft is provided with channels running through both ends thereof.

9. The surface thermal printing device according to claim 1, characterized in that: The device further comprises a loading mechanism and a unloading mechanism which are respectively arranged on the loading position and the unloading position.

10. The surface thermal printing device according to claim 9, characterized in that: The loading mechanism and the unloading mechanism both include a conveyor belt arranged along the left-right direction, and a suction cup module arranged above the front side of the conveyor belt and movable forward and backward; the loading mechanism also includes a transfer table arranged between the conveyor belt and the suction cup module, and a material transfer robot that moves the box workpiece to the transfer table.

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