Printing jig for curved surface

Abstract

A printing jig for a curved surface comprises a base used for fixing the curved surface and a printing silk screen located on the base, and the printing silk screen is provided with a hollow hole structure which is the same as a pattern to be printed and is opposite to an area to be printed on the curved surface. The device is characterized by further comprising a spotlight and an optical fiber assembly which are located on the printing silk screen and conduct projection on the hollowed-out hole structure, a screw hole corresponding to a to-be-printed area on the curved surface is formed in the top face of the base, the optical fiber assembly comprises an optical fiber and an installation base, and the installation base is in threaded connection in the screw hole; at least two small holes deviating from the central position of the mounting base are formed in the mounting base, optical fibers used for being connected with the controller are inserted into the small holes, and the at least two optical fibers can correspond to any two points on a graph in a to-be-printed area on the curved surface respectively. By adopting the jig disclosed by the utility model, the printing silk screen and the base can be ensured to be positioned at correct relative positions before printing, so that the rejection rate after curved surface printing is reduced, the production cost is saved, and the production efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of a printing jig, in particular to a printing jig used for printing graphics on a curved surface. Background Art

[0002] The control panels on some electrical appliances are often provided with through holes, and corresponding patterns or / and texts (hereinafter collectively referred to as graphics) are often printed on the surface of one side of the through holes to remind the operator to know the corresponding functions of the components (lights or buttons) exposed in the holes. At present, in order to improve the aesthetics of the product, the above-mentioned control panel has been gradually designed from the original plane structure to a curved surface shape. The jig, as an auxiliary machine in the printing device, can be used to improve the quality of the graphics printed on the curved surface. For example, the "Jig for Precision Printing of Upper Cover on Curved Surface" with the Chinese authorization announcement number CN215473780U discloses a jig specifically for curved surface printing. It includes a base and a support block, the support block is fixed in a side U-shaped groove on the top surface of the base, the top surface of the support block is inclined with the horizontal plane, the top surface of the support block is used to fit with the upper cover on the curved surface, the left and right sides of the support block are respectively provided with a left ear located below the printing section of the upper cover on the curved surface and a right ear located below the positioning section of the upper cover on the curved surface, and the front and rear sides of the support block are provided with a card slot for engaging with the buckle on the upper cover on the curved surface. When in use, the curved upper cover is placed on the top surface of the support block, and the card slots on the front and rear sides are engaged with the buckles on the curved upper cover to make the curved upper cover accurately and stably placed on the support block to avoid misalignment during printing. At the same time, the tightening assembly provided on the upper part of the left ear is used to achieve accurate fixation of the printing section to ensure better quality of the printed products.

[0003] However, this type of jig does not consider the precise alignment between the printing screen (the printing screen is installed on a movable seat, which is placed on the movable arm of the printing device and can move up and down with the movable arm) and the support block before printing, that is, it does not consider the precise alignment between the printing screen and the printed surface. If the calibration between the two is performed only with the naked eye, it takes multiple adjustments to obtain a qualified surface with printed graphics, that is, a lot of waste is often generated at the beginning of printing. Therefore, this type of existing jig needs to be further improved. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a printing jig for curved surfaces in view of the current status of the prior art, which can ensure the precise alignment between the printing screen and the base before printing, thereby reducing the generation of waste.

[0005] The technical solution adopted by the utility model to solve the above technical problems is: a printing fixture for curved surfaces, comprising a base and a printing screen located on the base, the base is used to fix the curved surface having an area to be printed, and the top surface of the base is designed to be an upwardly convex upper arc surface that fits the curved surface, the printing screen is installed on a movable seat that can move up and down, and has an upwardly concave lower arc surface that fits the curved surface, and a hollow structure with the same shape as the figure to be printed and opposite to the area to be printed on the curved surface is opened on the printing screen, characterized in that: it also includes a spotlight located on the above-mentioned printing screen for projecting onto the hollow structure and an optical fiber assembly installed in the base, a screw hole corresponding to the area to be printed on the curved surface is opened on the top surface of the base, the optical fiber assembly includes an optical fiber and a mounting seat, the mounting seat is threadedly connected in the screw hole, and the mounting seat is opened with at least two small holes deviated from the center position of the mounting seat, each small hole is inserted with the optical fiber used to connect to the controller, and the at least two optical fibers can respectively correspond to any two points on the figure in the area to be printed on the curved surface.

[0006] In the above solution, in order to quickly position the curved surface on the base, preferably, a positioning groove is provided on the top surface of the base for the protrusion on the curved surface to sit on, and an upright positioning pin is provided in the positioning groove, and the positioning pin is used to be inserted into the fixing hole on the curved surface. In this way, the structure is compact and the positioning is reliable.

[0007] In the above preferred solution, it is further preferred that there is a gap between the positioning pin and the mounting hole, and the gap is no greater than 0.1 mm.

[0008] In each of the above solutions, there are two spotlights and correspondingly, there are also two optical fiber assemblies. Using multiple spotlights and optical fiber assemblies makes the relative position between the printing screen and the base more accurate.

[0009] In the above-mentioned solutions, in order to avoid damaging the surface during curved surface printing, it is preferred that a buffer pad is provided in a local area of ​​the top surface of the base for the curved surface to fit against.

[0010] In the above schemes, the movable seat includes an arc-shaped main body for the printing screen to sit on and mounting sections located on both sides of the arc-shaped main body. The mounting sections on both sides are respectively fixed in the front and rear extending slide grooves of the two movable arms of the printing device through their own cam wrench mechanisms, thereby realizing rapid assembly and disassembly of the movable seat and the printing screen.

[0011] In order to facilitate the installation of the spotlight, the spotlight is hinged on an inverted U-shaped bracket, and the two ends of the bracket are respectively placed on the two movable arms.

[0012] In the above preferred scheme, further, the cam wrench mechanism includes a lower wedge block, an upper wedge block resting on the lower wedge block, a locking rod passing through the upper wedge block and the corresponding movable arm along the width of the upper wedge block, a cam hinged on the exposed end of the locking rod and abutting against the corresponding movable arm, and a handle connected to the cam, the height of the lower wedge block gradually increases from the arc-shaped body to the outside, and the height of the upper wedge block gradually decreases from the arc-shaped body to the outside, and the lower wedge block is constrained on the corresponding movable arm and can move up and down.

[0013] In order to quickly release the movable seat, a return spring is sleeved on the locking rod, one end of the return spring abuts against the outer side surface of the upper wedge block, and the other end abuts against the inner surface of the slide groove of the movable arm, so that the upper wedge block always has a tendency to move toward the arc-shaped main body side.

[0014] Compared with the prior art, since the utility model adds a spotlight for irradiating the perforated structure of the printing screen and an optical fiber arranged in the base, when the optical fiber can receive the light passing through the perforated structure, it can accurately transmit the optical signal to the controller. With the help of the controller's judgment on the strength of the optical signal, it is possible to obtain a conclusion on whether the printing screen is aligned with the base. Therefore, by using the fixture of the utility model, it is possible to ensure that the printing screen and the base are in the correct relative position before printing, thereby reducing the scrap rate after curved surface printing, saving production costs, and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a three-dimensional schematic diagram of an embodiment of the utility model installed on a workbench of a printing device;

[0016] Figure 2 for Figure 1 The schematic diagram of the three-dimensional structure after the workbench, the base and the curved surface to be printed are moved downward;

[0017] Figure 3 for Figure 2 A schematic diagram of the three-dimensional structure of the curved surface to be printed after being decomposed from the base;

[0018] Figure 4 for Figure 3 A further three-dimensional decomposition diagram of

[0019] Figure 5 is a three-dimensional schematic diagram of the base;

[0020] Figure 6 It is a three-dimensional schematic diagram of an embodiment of the utility model in a printing state. DETAILED DESCRIPTION

[0021] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0022] like Figure 1 The jig is installed on the workbench of the printing device. In the figure, the printing device only shows the workbench 10 and its two movable arms 20, wherein the workbench 10 is used to position the base 1 described below; the movable arms 20 are used to carry the printing screen 2 described below, and can drive the printing screen 2 to move up and down. Since the printing device is a prior art, it will not be described in detail here.

[0023] The above jig is used to assist in printing patterns and / or text on curved surfaces. Figures 1 to 6 As shown, the fixture includes a base 1, a printing screen 2, a spotlight 3 and an optical fiber assembly 4, wherein the base 1 is used to fix the curved surface 100 to be printed. In the figure, the curved surface 100 has five areas 101 to be printed (of course, different products have different numbers of areas to be printed). For ease of understanding, they are represented by circles. The base 1 is positioned on the workbench 10 of the printing device, and the positioning method of the base 1 can adopt any structure in the prior art. The base 1 in the figure is positioned on the workbench 10 by vacuum adsorption. Specifically, the workbench 10 is designed as a hollow structure, and the hollow structure is connected to a vacuum pump (not shown in the figure) through a pipeline. A plurality of small holes connected to the hollow structure are spaced apart on the surface of the workbench 10, and the base 1 is placed on the workbench 10 above the small holes. In this way, when the vacuum pump is started, a negative pressure is formed in the hollow structure of the workbench 10, and the base is firmly adsorbed on the workbench through the small holes. In order to place the curved surface 100 to be printed, the top surface of the base 1 is also designed to be an upwardly protruding upper arc surface 11 that fits the curved surface, and a positioning groove 12 is provided on the top surface of the base 1 for the protrusion on the curved surface to sit, and an upright positioning pin 13 is provided in the positioning groove 12, and the positioning pin 13 is used to be inserted into the fixing hole on the curved surface 100. In this way, after the curved surface 100 is installed, the positioning groove 12 can be used to allow the curved surface 100 to be quickly and accurately placed in place, and with the help of the positioning pin 13, the curved surface 100 will not easily move relative to the base 1. At the same time, considering the rapid alignment of the two, there is an appropriate gap between the positioning pin 13 and the mounting hole. Specifically, the gap is not greater than 0.1mm, which not only ensures the alignment of the two, but also enables the rapid plug-in of the two. At the same time, in order to avoid crushing the lower surface of the curved surface, a buffer pad 5 for the curved surface to fit is provided in a local area of ​​the top surface of the base 1 to protect the surface quality of the curved surface 100.

[0024] The printing screen 2 is located on the base 1 and has an upwardly concave lower arc surface that fits the curved surface 100. In the figure, the printing screen 2 is designed as an arc-shaped sheet body that matches the curved surface. A perforated structure 21 with the same shape as the graphics to be printed and opposite to the area 101 to be printed on the curved surface is opened on the printing screen. Since there are five areas 101 to be printed, there are also five perforated structures 21 on the printing screen. The shapes of the perforated structures 21 can be the same or different. For example, when the graphics are in the shape of a power symbol, the shape of the perforated structure is the hole shape of the power symbol, which is also represented by a circle in the figure. And the printing screen is also installed on the above-mentioned movable seat 6 as in the prior art. Since the movable seat 6 is installed on the two movable arms 20 of the printing device, the movable arms 20 can move up and down, so the printing screen 2 can also move up and down with the movable seat 6 and the movable arms 20. Specifically, in order to facilitate the installation of the movable seat 6, in this embodiment, the movable seat 6 includes an arc-shaped main body 61 for the printing screen 2 to be seated and mounting sections 62 located on both sides of the arc-shaped main body. The mounting sections 62 on both sides are respectively fixed in the front and rear extending slide grooves 201 of the two movable arms 20 of the printing device through their own cam wrench mechanisms 7. The cam wrench mechanism 7 preferably adopts the following structure, which includes a lower wedge 71, an upper wedge 72 resting on the lower wedge, a locking rod 73, a cam 74 and a handle 75 connected to the cam, wherein the height of the lower wedge 71 gradually increases from the arc-shaped body 61 to the outside, and the lower wedge 71 is constrained on the corresponding movable arm 20 and can move up and down. In the figure, a guide groove 202 extending in the up and down direction is opened on the movable arm 20, and a guide rod 711 inserted in the guide groove is provided on the outer surface of the lower wedge 71. The outer end of the guide rod 711 is exposed to the corresponding movable arm 20 and is screwed with a limit nut or a limit pin (not shown in the figure) to prevent the lower wedge 71 from being separated from the movable arm 20. The height of the upper wedge 72 gradually decreases from the arc-shaped body 61 to the outside. The locking rod 73 passes through the upper wedge block 72 and the corresponding movable arm 20 along the width direction of the upper wedge block 72 so that its end is exposed outside the movable arm 20; the cam 74 is hinged on the exposed end of the locking rod 73 and abuts against the corresponding movable arm 20. In this way, applying force to the handle 75 can make the cam 74 rotate, and the circumferential surface of the cam 74 with different radii abuts against the outer side surface of the movable arm 20, pulling the locking rod 73, so that the upper wedge block 72 moves away from the arc-shaped body 61, and pushes the lower wedge block 71 downward to press the mounting section 62 of the movable seat in the slide groove 201 of the movable arm, so as to achieve the positioning of the movable seat 6. At the same time, in order to quickly release the upper wedge block 72, a return spring 76 is also sleeved on the above-mentioned locking rod 73, one end of which abuts against the outer side surface of the upper wedge block 72, and the other end abuts against the inner surface of the slide groove 201 of the movable arm 20, so that the upper wedge block 72 always has a tendency to move toward the arc-shaped body 61.That is, once the cam 74 is rotated in the opposite direction, the upper wedge block 72 is moved toward the arc-shaped main body 61 under the action of the return spring 76 to release the pressure on the mounting section of the movable seat 6. Obviously, such a locking method is adopted, and the movable seat 6 can be positioned quickly, and after unlocking, it is also convenient to move quickly back and forth in the slide groove as needed.

[0025] The above-mentioned spotlight 3 is located above the above-mentioned printing screen 2 so as to illuminate the perforated structure 21 on the printing screen 2. There are many ways to install the spotlight 3, such as being installed on the free end of the cantilever, and the other end of the cantilever is hinged on the frame of the printing device. However, in the figure, the spotlight 3 is installed on an inverted U-shaped bracket 8, and the two ends of the bracket 8 are respectively placed on the above-mentioned two movable arms 20. In this way, the structure is the simplest and most stable, and multiple spotlights 3 can be set as needed to improve the alignment accuracy. In the figure, two spotlights 3 are set, and the two are distributed at intervals, and the shell of the spotlight 3 can be rotated relative to the bracket 8, that is, the spotlight 3 is hinged on the bracket 8, so that the light irradiation direction of the spotlight 3 can be easily adjusted so that the light irradiation direction is perpendicular to the cross-section of the center of the perforated structure 21, ensuring that the light passes vertically through the perforated structure 21 on the printing screen 2.

[0026] The optical fiber assembly 4 is installed in the base 1, and the number of the optical fiber assembly 4 matches the number of the spotlights 3. In order to conveniently install the optical fiber assembly 4, a screw hole 14 corresponding to the area to be printed on the curved surface is also opened on the top surface of the base 1. Each optical fiber assembly 4 includes an optical fiber 41 and a mounting seat 42. The mounting seat 42 is threadedly connected in the screw hole 14. The mounting seat 42 is provided with a small hole 421 deviated from the center position of the mounting seat (when two optical fiber assemblies 4 are arranged on the base 1, each mounting seat 42 needs to have at least one small hole; when only one optical fiber assembly 4 is arranged on the base 1, the mounting seat 42 needs to have two or more small holes). In the figure, there are four small holes in the mounting seat 42, which are radially spaced, and three or four small holes can also be circumferentially spaced, etc., and optical fibers 41 are inserted in each small hole, and optical fibers 41 can also be inserted in some of the small holes. The more optical fibers 41 there are, the higher the alignment accuracy. Each optical fiber 41 must correspond to the pattern in the area to be printed on the curved surface, that is, the projection point of each optical fiber must fall on the pattern, which can be ensured by the above-mentioned insertion of the positioning pin 13 and the mounting hole. Each optical fiber is then connected to the controller of the printing device (not shown in the figure). The controller is configured to receive the signal of the optical fiber and compare it with the pre-set standard signal value (optical power value) to determine the strength of the optical fiber signal. When the optical fiber signal is greater than the standard signal value, it indicates that the printing screen is aligned with the base. Otherwise, the base needs to be adjusted until the optical fiber signal is greater than the standard signal value before the printing operation can begin. The judgment conclusion can be displayed on the display screen or prompted by an alarm signal.

[0027] When in use, before starting printing, let the movable seat move back and forth in the slide slot of the movable arm, and when necessary, the spotlight can be rotated until the light of the spotlight can vertically pass through the hollow structure on the printing screen; then turn the handle to position the movable seat on the movable arm in the above manner; then place the base with the optical fiber assembly on the workbench, first visually check to make the base roughly aligned with the printing screen; then let the movable arm drive the movable seat and the printing screen to descend to the normal printing position, and then move the position of the base on the workbench until the display shows that the optical fiber has passed through the hollow structure of the printing screen. Sufficient light is obtained in the hole structure, which means that the hollow structure on the printing screen corresponds to the screw hole on the base, that is, the hollow structure on the printing screen corresponds to the printing area on the curved surface. At this time, start the vacuum pump to firmly adsorb the base on the workbench; then move the movable arm, movable seat and printing screen up, remove the bracket and spotlight; finally, place the curved surface to be printed on the base, insert the positioning pins into the corresponding mounting holes of the curved surface, and the curved surface has been positioned relative to the base; finally, lower the printing screen as in the prior art, and start the printing device to perform printing operations.

[0028] Obviously, by using the jig of this embodiment, before printing, the perforated structure of the printing screen is accurately aligned with the screw holes on the base, and then the reliable positioning between the curved surface to be printed and the base is utilized to ensure that the perforated structure of the printing screen accurately corresponds to the area to be printed on the curved surface. Thus, at the beginning of the printing operation, a qualified curved surface with a printed pattern can be obtained, thereby reducing the scrap rate of the printed curved surface, saving production costs, and improving production efficiency.

Claims

1. A printing jig for a curved surface, comprising a base (1) and a printing screen (2) located on the base, wherein the base (1) is used to fix a curved surface (100) having an area to be printed, and the top surface of the base (1) is designed to be an upwardly convex upper arc surface (11) that fits the curved surface, the printing screen (2) is mounted on a movable seat (6) that can move up and down, and has an upwardly concave lower arc surface that fits the curved surface, and a perforated structure (21) having the same shape as a pattern to be printed and corresponding to the area to be printed on the curved surface is opened on the printing screen (2), characterized in that: It also includes a spotlight (3) located above the printing screen (2) for projecting light onto the perforated structure, and an optical fiber assembly (4) installed in the base (1), wherein a screw hole (14) corresponding to the area to be printed on the curved surface is formed on the top surface of the base (1), and the optical fiber assembly (4) includes an optical fiber (41) and a mounting seat (42), wherein the mounting seat (42) is threadedly connected in the screw hole (14), and the mounting seat (42) is formed with at least two small holes (421) offset from the center position of the mounting seat, and each small hole is inserted with the optical fiber (41) for connecting to a controller, and the at least two optical fibers (41) can respectively correspond to any two points on the graphic in the area to be printed on the curved surface.

2. The printing jig according to claim 1, characterized in that: A positioning groove (12) is provided on the top surface of the base (1) for the protrusion on the curved surface to sit on, and an upright positioning pin (13) is provided in the positioning groove. The positioning pin (13) is used to be inserted into a fixing installation hole on the curved surface (100).

3. The printing jig according to claim 2, characterized in that: There is a gap between the positioning pin (13) and the mounting hole, and the gap is no greater than 0.1 mm.

4. The printing jig according to claim 1, 2 or 3, characterized in that: There are two spotlights (3), and correspondingly, there are also two optical fiber assemblies (4).

5. The printing jig according to claim 1, 2 or 3, characterized in that: A buffer pad (5) is provided in a local area of ​​the top surface of the base (1) for the curved surface to fit against.

6. The printing jig according to claim 1, 2 or 3, characterized in that: The movable seat (6) comprises an arc-shaped main body (61) for the printing screen (2) to sit on and mounting sections (62) located on both sides of the arc-shaped main body, and the mounting sections on both sides are respectively fixed in the front and rear extending slide grooves (201) of the two movable arms of the printing device through respective cam wrench mechanisms (7).

7. The printing jig according to claim 6, characterized in that: The spotlight (3) is hinged on an inverted U-shaped bracket (8), and the two ends of the bracket (8) are respectively placed on the two movable arms (20).

8. The printing jig according to claim 6, characterized in that: The cam wrench mechanism (7) comprises a lower wedge block (71), an upper wedge block (72) resting on the lower wedge block, a locking rod (73) passing through the upper wedge block and the corresponding movable arm along the width of the upper wedge block, a cam (74) hinged on the exposed end of the locking rod and abutting against the corresponding movable arm, and a handle (75) connected to the cam, the height of the lower wedge block (71) gradually increases from the arc-shaped body to the outside, and the height of the upper wedge block (72) gradually decreases from the arc-shaped body to the outside, and the lower wedge block (71) is constrained on the corresponding movable arm (20) and can move up and down.

9. The printing jig according to claim 8, characterized in that: The locking rod (73) is sleeved with a return spring (76), one end of which abuts against the outer side surface of the upper wedge block (72), and the other end of which abuts against the inner surface of the slide groove of the movable arm (20), so that the upper wedge block (72) always has a tendency to move toward the arc-shaped main body (61).

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