A screen printing method and a screen printing apparatus

Abstract

The application provides a screen printing method and a screen printing device. The screen printing method comprises the following steps: rotating a workpiece to be printed; pressing a screen against the workpiece by a squeegee, and moving the screen to print the workpiece; in response to a printing starting area of the workpiece being rotated to a set angle, turning on a pre-curing light source to pre-cure the printing starting area, and transferring the printed workpiece to a subsequent work station for formal curing. The pre-curing of the printing starting area can reduce the fluidity of the ink in the printing starting area, thereby reducing the ink seepage phenomenon during rotation and preventing the ink in the printing starting area from being pushed and accumulated when the printing ending area is printed. The screen printing method can improve the printing quality of the overlapping area. Since the pre-curing light source has a weak light intensity and a short opening time, the risk of screen exposure to light is reduced, and the stability of the printing process is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of screen printing, and in particular to a screen printing method and a screen printing device. BACKGROUND

[0002] In related screen printing processes, printing and curing are performed in two stations, and the ink on the screen is first transferred to the printing object by a squeegee, and then the surface of the printing object is subjected to photocuring treatment.

[0003] When printing the side surface of a cylindrical object (such as a circular tube, a bottle, etc.), the printing object is rotated during printing, so that the side surface is sequentially printed. For a pattern covering the entire side surface (i.e., head-to-tail), in order to ensure that there is no joint between the starting end and the ending end of printing, and the head and tail (i.e., the starting end and the ending end) of the pattern are accurately connected, the printing angle of the printing object is usually designed to be greater than 360°, so that the ending area and the starting area overlap together. At this time, since the ink has not been cured, on the one hand, the ink of the starting edge may spread to the unprinted side during the rotation process, and on the other hand, the ink of the starting area will further flow under the action of the squeegee when the printing ending area is printed, resulting in inaccurate connection, irregular edge, ink accumulation, poor printing consistency, etc. in the overlapping area, which is difficult to meet the demand for high-quality products.

[0004] Some related technologies choose to perform curing at the same time as printing, but curing has a high requirement for light intensity, and is prone to light leakage problems. If the curing time is too short, it may also result in an unsatisfactory curing effect. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a screen printing method and a screen printing device, which can improve the printing quality of the connected and overlapping areas.

[0006] According to the screen printing method provided by the present application, the following steps are included: rotating a workpiece to be printed; a squeegee presses a screen against the workpiece, and the screen moves to print the workpiece; in response to the rotation of the printing starting area of the workpiece to a set angle, a pre-curing light source is turned on to perform a preliminary semi-curing on the printing starting area, and the printed workpiece is transferred to a subsequent station for formal curing.

[0007] According to the screen printing method provided in the application, at least the following technical effects are achieved: the flowability of the ink at the printing starting area is reduced by pre-curing the printing starting area, which reduces the ink seepage phenomenon during rotation and prevents the ink at the starting area from being pushed and accumulated when the printing is stopped, and the screen printing method improves the printing quality of the joint and overlapping area. Since the pre-curing light source has a weak light intensity and a short opening time, the risk of screen exposure is reduced, and the stability of the printing process is improved.

[0008] According to some embodiments of the application, the pre-curing light source is turned off in response to the opening time of the pre-curing light source reaching a set time, and the set time is less than or equal to 50 ms.

[0009] According to some embodiments of the application, the pre-curing light source is turned off in response to the rotation angle of the workpiece reaching a set angle after the pre-curing light source is turned on, and the set angle is greater than or equal to 2° and less than or equal to 10°.

[0010] The screen printing device provided in the application is used to implement the screen printing method provided in the application, and includes a screen, a squeegee, a workpiece mounting table, and a pre-curing light source. The squeegee is located on one side of the screen, the workpiece mounting table is located on the other side of the screen, the workpiece mounting table is used to clamp and rotate the workpiece, the pre-curing light source is arranged on the same side of the workpiece mounting table, the pre-curing light source faces the placement position of the workpiece, and the pre-curing light source is used to pre-cure the printing starting area of the workpiece.

[0011] According to some embodiments of the application, the screen printing device further includes a light shielding member located between the pre-curing light source and the screen to block the outgoing light of the pre-curing light source from being directed to the screen.

[0012] According to some embodiments of the application, the light shielding member is mounted on the pre-curing light source, and the light shielding member is formed with a light emitting slot parallel to the rotation shaft of the workpiece.

[0013] According to some embodiments of the application, the light shielding member includes a cover, and two covers are respectively located on the two sides of the pre-curing light source, and the light emitting slot is formed between the two covers.

[0014] According to some embodiments of the application, the workpiece is placed between the screen and the pre-curing light source to block the outgoing light of the pre-curing light source from being directed to the screen.

[0015] According to some embodiments of the application, the pre-curing light source is located below the workpiece.

[0016] According to some embodiments of the present application, the screen printing device comprises a light source mounting assembly, the pre-curing light source is mounted on the light source mounting assembly, and the position of the pre-curing light source is adjustable. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the references to the figures, in which:

[0018] Figure 1 is a flowchart of a screen printing method according to an embodiment of the present application;

[0019] Figure 2 is a partial structural schematic diagram of a screen printing device according to an embodiment of the present application;

[0020] Figure 3 is a partial structural schematic diagram of a screen printing device according to an embodiment of the present application.

[0021] LIST OF REFERENCE NUMERALS

[0022] squeegee 110, screen 210, pre-curing module 300, light outlet slot 321, cover 322, mounting seat 331, first movable member 332, second movable member 333, first knob 334, second knob 335,

[0023] workpiece 900. DETAILED DESCRIPTION

[0024] Embodiments of the present application are described in detail below with reference to the accompanying drawings, in which examples of embodiments are shown, wherein the same or similar numerals throughout the drawings represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0025] In the description of the present application, it should be understood that, in relation to the orientation description, for example, the orientation or position relationship indicated by "center", "lengthwise", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0026] In the description of the present application, the meaning of several is one or more, the meaning of multiple is more than two, greater than, less than, more than, etc. are understood as not including the number, above, below, within, etc. are understood as including the number. If it is described to the first, the second is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of the indicated technical features.

[0027] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0028] Curved screen printing is applied to the side surface printing of cylindrical products such as beverage bottles. In order to make the printing effect of the side surface complete without seams, the printing angle is usually designed to be greater than 360°, so there is an overlapping area of ink.

[0029] In order to solve the problems of irregular edge lines, ink accumulation and poor printing consistency that are prone to occur in the overlapping area, a variety of schemes are proposed in the related art.

[0030] Some related technologies choose to improve the stability or strength of the scraper, so that it is not easy to shake when printing the overlapping area, and the force on the ink is more uniform, thereby improving the consistency of the flow effect of the ink in the starting area. However, this cannot solve the problem of ink flow under the action of the scraper, and the ink is still prone to accumulate.

[0031] Some related technologies choose to reduce the speed when printing the overlapping area, which can also make the printing of the scraper more stable, but the problem of ink accumulation still exists, and the repeated increase and decrease of speed will increase the control difficulty and reduce the production efficiency.

[0032] Some related technologies choose to solidify at the same time of printing, that is, the solidification station and the printing station which are originally separated are integrated together, so that when printing the terminal area, the ink printed first (that is, the ink in the starting area) has been solidified and will not flow and accumulate. However, light curing has a high requirement for light intensity, and is prone to light leakage problems, which can cause the holes of the screen to be blocked, causing the screen printing equipment to malfunction. Moreover, with the improvement of production efficiency, the rotation speed of the workpiece is also increasing, and the short solidification time may result in unsatisfactory solidification effect.

[0033] Referring to Figure 1 and Figure 2 , the screen printing method provided by the present application comprises the following steps.

[0034] Rotating the workpiece to be printed 900;

[0035] The squeegee 110 presses the screen 210 against the workpiece 900, and the screen 210 moves to print the workpiece 900;

[0036] In response to the printing start area of the workpiece 900 rotating to a set angle, the pre-curing light source is turned on to pre-cure the printing start area;

[0037] The printed workpiece 900 is transferred to a subsequent station for formal curing.

[0038] According to the screen printing method provided in the present application, the pattern applied to the side surface has a head-to-tail connection, or the printing angle of the side surface of the workpiece is greater than or equal to 360°. By pre-curing the printing start area, the flowability of the ink in the printing start area can be reduced, on the one hand, to reduce the seepage phenomenon of the ink during rotation, and on the other hand, to prevent the ink in the printing start area from being pushed and accumulated when the printing termination area is reached. The screen printing method can improve the printing quality of the overlapping area.

[0039] It should be emphasized that the pre-curing is only a preliminary and temporary curing, not a complete curing, so the present application defines it as "semi-curing". "Semi" means that the ink is in an intermediate state of curing but not completely cured, and it is not required that the curing degree of the ink is exactly half. The pre-curing only needs to increase the viscosity of the ink to prevent seepage and being pushed by the squeegee 110.

[0040] Since it is pre-curing, the required light intensity is low, and the pre-curing light source can be selected as a low-intensity ultraviolet light source, for example, an LED lamp containing a certain ultraviolet spectrum. Moreover, since only the printing start area is pre-cured, not the entire surface, the pre-curing light source is turned on for a short time. The above two reasons make it easy to solve the light leakage problem of the pre-curing light source, thereby reducing the risk of light exposure of the screen, and the screen printing method can improve the stability of the printing process.

[0041] Moreover, since the pre-curing requires low light intensity, the irradiation time required for pre-curing can also be shortened, thereby reducing the impact on the printing speed of the workpiece 900. For example, the irradiation time can be limited to milliseconds, that is, in the screen printing method, the pre-curing light source can be turned off in response to the opening time of the pre-curing light source reaching a set time, and the set time can be set to be less than or equal to 50 ms, or even less than or equal to 20 ms.

[0042] In addition to controlling the pre-curing light source by time, the pre-curing light source can also be controlled by the rotation angle of the workpiece 900, so as to control the pre-cured area to be in the printing starting area, and avoid the pre-cured area being too large. For example, in the screen printing method, the pre-curing light source can be turned off in response to the rotation angle of the workpiece 900 reaching a set angle after the pre-curing light source is turned on. The set angle can be greater than or equal to 2° and less than or equal to 10°.

[0043] The other printing areas except the printing starting area are not affected by the pre-curing light source, and thus remain in the uncured state. During the rotation of the workpiece, the ink in the uncured area can be fully leveled, so as to obtain a high-quality printing effect.

[0044] For example, with reference to Figure 2 and Figure 3 , the application also provides a screen printing device for implementing the screen printing method. The screen printing device includes a screen 210, a squeegee 110, a workpiece mounting table (not shown in the figure), and a pre-curing module 300. The pre-curing module 300 has a pre-curing light source (not shown in the figure). The squeegee 110 is located on one side of the screen 210. The workpiece mounting table is located on the other side of the screen 210 and is used to clamp and rotate the workpiece 900. The pre-curing light source is arranged on the same side of the workpiece mounting table and faces the placement position of the workpiece 900. The pre-curing light source is used to pre-cure the printing starting area of the workpiece 900.

[0045] The screen printing device is used to implement the screen printing method, and thus has the beneficial effects of the screen printing method. Here, the screen printing method will not be described again.

[0046] It can be understood that the key of the screen printing method is the pre-curing step. The other steps in the screen printing process (such as pretreatment before printing and formal curing after printing) are not particularly required as long as they do not interfere with the pre-curing step. Therefore, the application scenario of the screen printing method is not limited to the screen printing device in Figure 2 , Figure 3 , but can be widely applied to various screen printing devices and adapt to different models of screen printing devices.

[0047] Although the pre-curing light source has been limited in the screen printing method by shortening the opening time and reducing the light intensity, if there is light leakage in the screen printing device, the screen 210 is irradiated by light for a long time, and the ink in the holes of the screen 210 can still be cured, which can cause the screen to be blocked and affect the printing effect. Therefore, the screen printing device needs to further reduce the risk of light leakage.

[0048] To this end, in some embodiments, the screen printing apparatus further comprises a light shielding member located between the pre-curing light source and the screen 210 to block the emergent light of the pre-curing light source from being projected to the screen 210, so as to reduce the risk of light leakage as much as possible.

[0049] The light shielding member can be mounted on the pre-curing light source, that is, the light shielding member is integrated in the pre-curing module 300, and the light shielding member is formed with a light exit slit 321 parallel to the rotation axis of the workpiece 900. At this time, the light shielding member can not only shield the light projected to the screen 210, but also shield the light projected to the workpiece 900. The light can only irradiate a small area on the workpiece 900 through the light exit slit 321, so as to ensure that only the required area (i.e. the printing starting area of the workpiece 900) is pre-cured. For example, referring to Figure 2 and Figure 3 The light shielding member comprises a cover 322 located on both sides of the pre-curing light source, and the light exit slit 321 is formed between the two covers 322. The cover 322 surrounds the pre-curing light source, so that the light of the pre-curing light source can only irradiate the workpiece 900 through the light exit slit 321.

[0050] It can be understood that the light shielding member does not need to be opaque except for the light exit slit 321. For example, the cover 322 can be provided with heat dissipation holes or other purpose holes at positions not facing the screen 210, as long as the emergent light from the holes cannot irradiate the screen 210.

[0051] Of course, in addition to mounting the light shielding member on the pre-curing light source, other ways can also be used to protect the screen 210. For example, the light shielding member can be provided as a light shielding plate independent of the pre-curing module 300. The light shielding plate is located between the workpiece 900 and the screen 210 and is arranged parallel to the screen 210. The light shielding plate is provided with an avoidance slot, and the position of the avoidance slot matches the printing position. Only a part of the screen 210 pressed by the squeegee 110 passes through the avoidance slot to contact the surface of the workpiece, and the other part of the screen 210 is blocked by the light shielding plate and cannot be irradiated by the pre-curing light source.

[0052] In some embodiments, in order to avoid the emergent light irradiating the screen 210, the workpiece 900 can also be placed between the screen 210 and the pre-curing light source to block the emergent light of the pre-curing light source from being projected to the screen 210. It can be understood that here only the workpiece 900 is required to block the light path from the pre-curing light source to the screen 210. For example, referring to Figure 2 and Figure 3 Since the screen 210 is above the workpiece 900, the pre-curing light source can be arranged below the workpiece 900, and preferably directly below the workpiece 900.

[0053] In some embodiments, the pre-curing module 300 further includes a light source mounting assembly, on which the pre-cured light source is mounted. The position of the pre-cured light source is adjustable, thereby facilitating the adjustment of the screen printing equipment. For example, see... Figure 3 The light source mounting assembly includes a mounting base 331, a first movable member 332, and a second movable member 333. The first movable member 332 is mounted on the mounting base 331 and can move in a first direction (in... Figure 3 The second movable part 333 is mounted on the first movable part 332 and can move in the second direction (left and right). Figure 3 The pre-cured light source is mounted on the second movable part 333. The positions of the first movable part 332 and the second movable part 333 are adjusted by the first knob 334 and the second knob 335, so that the pre-cured light source has two degrees of freedom of adjustment.

[0054] Furthermore, in Figure 3 In the embodiments, the first active element 332 also has the function of being directed to a third party (in Figure 3 The connecting groove extends upward (in the front-to-back direction), and the second movable part 333 is installed through the connecting groove. The installation position of the second movable part 333 is adjustable, which further increases the degree of freedom of adjustment of the pre-cured light source.

[0055] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0056] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this application are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is changed and sub-operations described as part of a larger operation are executed independently.

[0057] While the embodiments of the application have been shown and described, it is to be understood that the embodiments can be varied, modified, substituted and changed by those skilled in the art without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. A screen printing method characterized by, The screen printing method comprises the following steps: rotating a workpiece to be printed; the printing angle of the side surface of the workpiece is greater than or equal to 360°; a squeegee presses the screen against the workpiece, and the screen moves to print the workpiece; in response to the rotation of the printing starting area of the workpiece to a set angle, a pre-curing light source is turned on to pre-cure the printing starting area; the pre-curing light source is arranged as a low-intensity ultraviolet light source; in response to the opening time of the pre-curing light source reaching a set time, the pre-curing light source is turned off, and the set time is less than or equal to 50 ms; the pre-curing is preliminary and temporary curing rather than complete curing, so as to increase the viscosity of the ink and prevent the ink from being easily pushed by the squeegee; the printed workpiece is transferred to a subsequent station for formal curing.

2. The screen printing method according to claim 1, characterized by in response to the rotation angle of the workpiece reaching a set angle after the pre-curing light source is turned on, the pre-curing light source is turned off, and the set angle is greater than or equal to 2° and less than or equal to 10°.

3. A screen printing apparatus characterized by comprising: The screen printing device is used to implement the screen printing method according to any one of claims 1 to 2, and the screen printing device comprises: a screen; a squeegee arranged on one side of the screen; a workpiece mounting table arranged on the other side of the screen, the workpiece mounting table being used to clamp a workpiece and drive the workpiece to rotate; a pre-curing light source arranged on the same side of the workpiece mounting table as the pre-curing light source, the pre-curing light source being arranged towards the placement position of the workpiece, and the pre-curing light source being used to pre-cure the printing starting area of the workpiece.

4. The screen printing apparatus according to claim 3, characterized by The screen printing device further comprises a light shielding member arranged between the pre-curing light source and the screen to block the light emitted by the pre-curing light source from being directed to the screen.

5. The screen printing apparatus according to claim 4, characterized by The light shielding member is mounted on the pre-curing light source, and the light shielding member is formed with a light emitting gap parallel to the rotation axis of the workpiece.

6. The screen printing apparatus according to claim 5, characterized by The light shielding member comprises two housings arranged on the two sides of the pre-curing light source, respectively, and the light emitting gap is formed between the two housings.

7. The screen printing apparatus according to claim 3, characterized by The workpiece is arranged between the screen and the pre-curing light source to block the light emitted by the pre-curing light source from being directed to the screen.

8. The screen printing apparatus according to claim 7, characterized by The pre-curing light source is arranged below the workpiece.

9. The screen printing apparatus according to claim 3, characterized by The screen printing device comprises a light source mounting assembly, the pre-curing light source is mounted on the light source mounting assembly, and the position of the pre-curing light source is adjustable.

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