Inkjet printhead and array assembly, printer and printing method comprising the same

Abstract

The application discloses an inkjet print head, an array assembly, a printer and a printing method comprising the same. The inkjet print head is configured to have a width not greater than a first width value when a radius of curvature of a substrate surface is less than a first set value, and to have a width between the first width value and a second width value when the radius of curvature of the substrate surface is between the first set value and a second set value. Wherein, a maximum effective ejection point of ink droplets ejected from a nozzle along an ejection direction and two side surfaces of a cartridge along the ejection direction form an ejection included angle at the widest position, and the width of the inkjet print head is the bottom width of the ejection included angle at the widest position of the two side surfaces of the cartridge. The inkjet print head, the array assembly, the printer and the printing method comprising the same can select different inkjet print heads according to different curvature of the substrate surface, so as to realize higher printing precision and stability on a concave surface or a multi-curvature surface.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inkjet printing, in particular to an inkjet printhead, an array assembly comprising the same, a printer and a printing method. BACKGROUND

[0002] The printhead is an important component of an inkjet printer, such as Figure 1 As shown in FIG. 1, the structure of an inkjet printhead 100 generally comprises a nozzle chip 120, a flexible printed circuit (FPC) 140 and a cartridge 110. The nozzle chip 120 forms an array of ejection channels and nozzles 130. The FPC 140 is a thin, foldable circuit board that provides driving signals for controlling ink ejection, and is electrically connected to the main board of the printer. The cartridge 110 stores ink, and the nozzle chip 120 and the FPC 140 are attached to the surface of the cartridge 110.

[0003] Traditional inkjet printheads mostly adopt a planar ejection structure, with the nozzle array distributed on a plane, which is only suitable for scanning printing on flat media. However, when the printing object has a significant curvature (such as the surface of a bottle, a groove, a mold or a 3D printed part), as shown in FIG. 2, the printhead is prone to collision with the printing object, and for some curved printing surfaces (i.e. the surface of the printing object), the nozzle face is not aligned with the normal direction of the printing surface, which can cause the ink droplet trajectory to deviate, collide with the wall, atomize or cover a blind area, resulting in a decrease in printing quality. Figure 2

[0004] The flight distance of an ink droplet in inkjet printing is significantly affected by the volume and ejection energy:

[0005] For larger ink droplets (≥20 pL), the maximum effective flight distance of a vertically ejected ink droplet is about 5 mm;

[0006] When the ejection angle deviates from the vertical direction, the flight distance of the ink droplet is usually shortened to 3 mm;

[0007] For small-volume ink droplets (1-10 pL), the flight distance of the ink droplet can be further reduced to 1-3 mm.

[0008] Therefore, the existing planar nozzle (i.e. printhead) is difficult to achieve uniform deposition or color printing on a concave surface with a small radius of curvature, which affects the printing accuracy and stability, thereby limiting the application of inkjet technology in three-dimensional surface functional coating, structural coloring and flexible electronic manufacturing, etc. SUMMARY

[0009] ​The technical problem to be solved by the present application is to overcome the defects of the prior art that the inkjet print head is difficult to print on a small curvature radius concave surface and the printing quality is poor, and to provide an inkjet print head, an array assembly comprising the same, a printer and a printing method.

[0010] The present application solves the above technical problems by the following technical solutions:

[0011] An inkjet print head comprises a cartridge storing ink and a print head chip provided on the cartridge, and a nozzle is formed on the print head chip; the inkjet print head is configured to:

[0012] When the curvature radius of the surface of the substrate is less than a first set value, the width of the inkjet print head is not greater than a first width value;

[0013] When the curvature radius of the surface of the substrate is between the first set value and a second set value, the width of the inkjet print head is between the first width value and a second width value; the second set value is greater than the first set value, and the second width value is greater than the first width value;

[0014] Wherein, the maximum effective ejection point of the ink droplet ejected from the nozzle in the ejection direction forms an ejection included angle with the two side surfaces of the cartridge in the ejection direction at the widest position, and the width of the inkjet print head is the bottom width of the ejection included angle at the widest position of the two side surfaces of the cartridge.

[0015] In the present application, the width of the inkjet print head is set according to the different surface curvature radii of the substrate, so that the ejection direction of the print head is more easily consistent with the normal direction of the surface of the substrate, avoiding the collision between the print head and the substrate, thereby achieving higher printing precision and stability on the concave surface or surface with multiple curvature radii. When the curvature radius of the surface of the substrate is less than a first set value, the surface of the substrate is a deep concave surface, by setting the width of the inkjet print head to be not greater than a first width value, i.e. reducing the width of the print head, avoiding the conflict between the edge of the cartridge of the print head and the protruding structure around the deep concave surface of the substrate when the print head is close to the substrate, the print head can be closer to the deep concave surface area, ensuring that the ink droplet is ejected within the maximum effective ejection distance, thereby ensuring the printing quality on the deep concave surface. When the curvature radius of the surface of the substrate is between the first set value and a second set value, the surface of the substrate is a medium concave surface, then the width of the inkjet print head can be appropriately increased to be between the first width value and a second width value, so that the inkjet print head is neither too wide nor too narrow, so that the cartridge has sufficient ink amount, avoiding frequent ink replacement, and improving the user experience.

[0016] Preferably, the two side surfaces of the cartridge in the ejection direction are inclinedly arranged so that the extension lines of the two side surfaces converge towards the maximum effective ejection point.

[0017] In the present solution, by the above arrangement, the box body forms a tilted conical structure, when the printhead approaches the surface of the printing object, the head of the conical structure will not touch the convex structure around the concave surface of the printing object, so that the printhead can approach the concave area, ensuring that the ink droplets are ejected within the range of the maximum effective ejection distance, thereby ensuring the printing quality.

[0018] Preferably, the included angle of the two sides is equal to the ejection angle.

[0019] In the present solution, by the above arrangement, when the printhead approaches the surface of the printing object, the distance from the printhead to the surface of the printing object is ensured to be within the range of the maximum effective ejection distance.

[0020] Preferably, the first set value is 8mm, and the second set value is 15mm; and / or, the first width value is 5mm, and the second width value is 10mm.

[0021] In the present solution, the above values are preferred values.

[0022] An inkjet printhead array assembly, comprising a plurality of inkjet printheads as described above.

[0023] In the present solution, by using the above inkjet printhead, different inkjet printheads can be selected according to the surface of the printing object with different curvatures, so as to achieve higher printing precision and stability on the concave surface or the surface with multiple curvatures, and adapt to the printing needs of irregular three-dimensional curved surfaces.

[0024] Preferably, the box body of the plurality of inkjet printheads has a shape consistent with the curvature of the printing object at different printing positions.

[0025] In the present solution, by the above arrangement, the shape of the box body is more adaptable to the different curved surfaces of the printing object, avoiding collision between the printhead and the printing object.

[0026] An inkjet printer, comprising an inkjet printhead as described above; or the inkjet printer comprises an inkjet printhead array assembly as described above.

[0027] In the present solution, by using the above inkjet printhead or the above inkjet printhead array assembly, different inkjet printheads can be selected according to the surface of the printing object with different curvature radii, so as to achieve higher printing precision and stability on the concave surface or the surface with multiple curvature radii, and adapt to the printing needs of irregular three-dimensional curved surfaces.

[0028] Preferably, the ejection direction of the nozzle is arranged to be consistent with the normal direction of the surface of the printing object.

[0029] In the present solution, by the above arrangement, the ejection direction of the ink droplets is perpendicular to the surface of the substrate, the landing error of the ink droplets is reduced, and thus the printing accuracy and quality are improved.

[0030] An inkjet printing method, comprising the steps of:

[0031] detecting a radius of curvature of a surface of a substrate;

[0032] configuring an inkjet printhead according to the radius of curvature, wherein

[0033] when the radius of curvature is less than a first set value, reducing a width of the inkjet printhead and reducing an ejection included angle of the inkjet printhead;

[0034] the ejection included angle is an included angle formed by a maximum effective ejection point of the inkjet printhead along an ejection direction and two side surfaces of a cartridge body of the inkjet printhead at a widest position along the ejection direction; and the width of the inkjet printhead is a bottom width of the ejection included angle at the widest position of the two side surfaces of the cartridge body.

[0035] In the present solution, by the above steps, the inkjet printing method can configure the inkjet printhead according to the different radius of curvature of the surface of the substrate, so that the ejection direction of the printhead is more likely to be consistent with the normal direction of the surface of the substrate, and the collision between the printhead and the substrate is avoided, thereby achieving higher printing accuracy and stability on a concave surface or a surface with multiple radii of curvature. When the radius of curvature is less than a first set value, the surface of the substrate is a deep concave surface. By reducing the width of the inkjet printhead, the edge of the cartridge body of the printhead is prevented from colliding with the protruding structure around the deep concave surface of the substrate when the printhead is close to the substrate, the printhead can be closer to the deep concave area, and the ink droplets can be ejected within the maximum effective ejection distance. By reducing the ejection included angle of the inkjet printhead, the degree of the printhead approaching the surface of the substrate (i.e., the distance from the ink ejection hole of the inkjet printhead to the surface of the substrate) can be increased, and the ink droplets can be further ensured to be ejected within the maximum effective ejection distance, thereby ensuring the printing quality on the deep concave surface.

[0036] Preferably, when the radius of curvature is less than the first set value, the width of the inkjet printhead is reduced to be not greater than a first width value.

[0037] The inkjet printhead is configured according to the radius of curvature, and the method further comprises:

[0038] when the radius of curvature is between the first set value and a second set value, the inkjet printhead is manufactured so that the width of the inkjet printhead is between a first width value and a second width value; the second set value is greater than the first set value, and the second width value is greater than the first width value.

[0039] In the present solution, the inkjet printing method, by the above steps, when the radius of curvature is less than the first set value, controls the width of the inkjet printhead in the range of no more than the first width value, which is the preferred width range. When the radius of curvature of the surface of the substrate is between the first set value and the second set value, the surface of the substrate is moderately concave, and the width of the inkjet printhead can be appropriately increased to between the first width value and the second width value, so that the inkjet printhead is neither too wide nor too narrow, so that the cartridge has sufficient ink, avoids frequent ink replacement, and improves user experience.

[0040] Preferably, the inkjet printhead configured according to the radius of curvature further comprises:

[0041] When the radius of curvature is between the first set value and the second set value, the spray angle of the inkjet printhead is reduced.

[0042] In the present solution, the inkjet printing method, by the above steps, can increase the degree of approach of the printhead to the surface of the substrate when printing on a moderately concave surface, and ensure that the ink droplets are sprayed within the maximum effective spray distance; thereby ensuring the printing quality on the moderately concave surface.

[0043] Preferably, the inkjet printhead configured according to the radius of curvature further comprises:

[0044] When the radius of curvature is greater than the second set value, the spray angle of the inkjet printhead is reduced.

[0045] In the present solution, when the radius of curvature is greater than the second set value, the surface of the substrate is gently concave, and by reducing the spray angle, the degree of approach of the printhead to the surface of the substrate can be increased, and the ink droplets can be sprayed within the maximum effective spray distance; which is conducive to improving the printing quality.

[0046] Preferably, the inkjet printing method further comprises:

[0047] Detecting the radius of curvature of the surface of the substrate at different positions along the printing direction;

[0048] Selecting the inkjet printhead of the corresponding shape cartridge according to the radius of curvature at different positions; the shape of the cartridge includes one or more combinations of strip shape, circular shape, and polygonal shape.

[0049] In the present solution, the inkjet printing method, by the above steps, can switch the inkjet printhead of different cartridge shapes according to the surface of the substrate with different radii of curvature, and different cartridge shape combinations can better adapt to the surface with different radii of curvature of the substrate (such as a three-dimensional curved surface structure), thereby improving the printing precision and quality.

[0050] Preferably, the inkjet printing method further comprises: setting the jetting direction of the inkjet printhead to be consistent with the normal direction of the surface of the substrate.

[0051] In the present solution, the inkjet printing method reduces the landing point error of the ink droplets by setting the jetting direction of the inkjet printhead to be consistent with the normal direction of the surface of the substrate, thereby improving the printing accuracy and quality.

[0052] The positive progress effect of the present application is that the inkjet printhead, the array assembly comprising the same, the printer and the printing method can select different inkjet printheads according to the surface of the substrate with different radii of curvature, thereby achieving higher printing accuracy and stability on the concave surface or the surface with multiple radii of curvature. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 It is a schematic diagram of the structure of the inkjet printhead of the prior art.

[0054] Figure 2 It is a schematic diagram of the structure of the inkjet printhead of the prior art colliding with the substrate.

[0055] Figure 3 It is a schematic diagram of the structure of the inkjet printhead of the present application and the substrate.

[0056] Figure 4 It is a schematic diagram of the structure of the inkjet printhead of the present application and the inkjet printhead of the prior art. The left side of the diagram represents the schematic diagram of the structure of the inkjet printhead of the present application, and the right side of the diagram represents the schematic diagram of the structure of the inkjet printhead of the prior art.

[0057] Figure 5 It is a geometric relationship model diagram of the inkjet printhead of the present application and the radius of curvature of the surface of the substrate.

[0058] Figure 6 It is a schematic diagram of the state when the jetting direction of the inkjet printhead of the present application is consistent with the normal direction of the surface of the substrate. The direction of the arrow pointing to the nozzle in the diagram is the normal direction B of the surface of the substrate, and the direction of the arrow pointing to the substrate is the jetting direction A.

[0059] REFERENCE NUMERALS:

[0060] Inkjet printhead 100, cartridge body 110, printhead chip 120, nozzle 130, flexible circuit board 140, ink droplet 200, substrate 300, radius of curvature R of the surface of the substrate, width W of the inkjet printhead, maximum effective jetting point P, jetting direction A, jetting angle a, normal direction B of the surface of the substrate, maximum effective flight distance L. DETAILED DESCRIPTION

[0061] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0062] Example 1

[0063] like Figure 3 As shown, this embodiment provides an inkjet printhead 100, which includes a cartridge 110 storing ink and a printhead chip 120 and a flexible printed circuit board 140 (FPC) disposed on the cartridge 110. The printhead chip 120 has nozzles 130 and jet channels (not shown in the figure).

[0064] The inkjet printhead in this embodiment has the same... Figure 1 The inkjet printhead 100 (also called a "printhead") has the same components as the inkjet printhead, but its shape and size are configured according to the different curvatures of the substrate 300 surface. Specifically, when the radius of curvature of the substrate 300 surface is less than a first set value, the substrate 300 surface is a deep concave surface, and the width of the inkjet printhead 100 is not greater than the first width value; when the radius of curvature of the substrate 300 surface is between the first set value and the second set value, the substrate 300 surface is a medium concave surface, and the width of the inkjet printhead 100 is between the first width value and the second width value; the second set value is greater than the first set value, and the second width value is greater than the first width value.

[0065] Among them, such as Figure 4 As shown, the maximum effective ejection point P of the ink droplet 200 ejected from the nozzle along the ejection direction forms an ejection angle with the two sides of the cartridge 110 along the ejection direction at the widest position. The width of the inkjet printhead 100 is the bottom width of the ejection angle at the widest position of the two sides of the cartridge 110.

[0066] To better understand the relationship between the above parameters and the radius of curvature R of the substrate 300 surface, Figure 5 The geometric relationship model between the above parameters and the radius of curvature R of the substrate surface is shown. In this geometric relationship model, the jet angle and the base of the two widest positions of the two sides of the cartridge 110 form an isosceles triangle. The width W of the inkjet printhead 100 (i.e., the printhead width) is equivalent to the base of the isosceles triangle. The distance from the nozzle 130 to the maximum effective jet point P is the maximum effective flight distance L of the ink droplet 200. The maximum effective flight distance L of the ink droplet 200 is equivalent to the height of the triangle. The angle between the maximum effective jet point P of the ink droplet 200 ejected by the nozzle 130 at the center of the printhead and the two sides of the cartridge 110 is the jet angle α (i.e., the apex angle). The jet angle reflects the geometric adaptation capability of the printhead on the concave curved surface.

[0067] Wherein, the geometric relationship between the nozzle (i.e. inkjet printhead 100) and the concave surface can be expressed as:

[0068] ;

[0069] The circumscribed circle radius of the isosceles triangle formed by the two ends and the center connecting line of the nozzle box 110 (corresponding to the curvature radius R of the surface of the substrate 300), and the geometric relationship between the maximum flight distance L of the ink droplet 200 and the width of the nozzle is:

[0070] .

[0071] Specifically, in the present embodiment, the preferred values of the above-mentioned various parameters (i.e. the various set values and width values) are: the first set value is 8 mm, and the second set value is 15 mm; the first width value is 5 mm, and the second width value is 10 mm.

[0072] When R < 8 mm, the surface of the substrate 300 is a deep concave surface, such as the deep concave surface often found in structures such as mold cavities, microgrooves, and narrow channel inner walls, which has the geometric characteristics of large curvature and deep concave, and requires high adhesion. In this case, we need to choose inkjet printheads 100 with smaller width. In the present embodiment, the first width value is optimally set to 5 mm. When selecting the first width value, the width of the printhead chip 120 is usually taken into consideration. In the present embodiment, the width of the printhead chip 120 is 4 mm, so the first width value should be no less than 4 mm, that is, the inkjet printhead 100 can be suitable for printing concave surfaces with a curvature radius R ≥ 4 mm.

[0073] When 8 mm ≤ R ≤ 15 mm, the surface of the substrate 300 is a medium concave surface, such as the medium concave surface found in structures such as grooves and arc-shaped cavities, which has the geometric characteristics of medium concavity and common engineering concave. In this case, we can slightly increase the width of the printhead. In the present embodiment, the second width value is optimally set to 10 mm.

[0074] When R > 15 mm, the surface of the substrate 300 is a gently concave surface or approximately a plane, such as the gently concave surface found in structures such as bottle bodies, plastic shells, and slight grooves, which has the geometric characteristics of slow change and small curvature. In this case, we can further increase the width of the printhead, which can be greater than 10 mm. It should be noted that when the surface of the substrate 300 is such a gently concave surface or approximately a plane, the degree of curvature of the surface is relatively gentle, which gives us more flexibility in choosing the inkjet printhead 100. The width of the inkjet printhead 100 can be wider, and we can also choose a printhead with a narrower width, and the range of the jet angle it adopts can be larger, but it is not limited to the angle range of the present embodiment.

[0075] The following table shows a specific example of the ink drop 200 flight distance values obtained in different types of concave surfaces, at different inkjet printhead 100 widths, and different jetting angles:

[0076]

[0077] In which, the data of serial numbers 1-3 correspond to the deep concave type, the data of serial numbers 4-6 correspond to the medium concave type, and the data of serial numbers 7-9 correspond to the flat concave type.

[0078] The radius of curvature R of the surface of the substrate (i.e. the circumscribed circle radius) reflects the ability of the printhead to adapt to the depth of the concave surface, and its characteristics are:

[0079] The smaller the radius of curvature (R is smaller): the deeper the concave surface, the greater the curvature (the curvature is the inverse of the radius of curvature R), and the stronger the geometric adaptability of the printhead is required;

[0080] The larger the radius of curvature (R is larger): the flatter the concave surface, and the lower the geometric adaptability requirement of the printhead.

[0081] From the above table, it can be seen that:

[0082] When the width W of the inkjet printhead changes or the maximum effective flight distance L changes, the jetting angle a and the radius of curvature R of the surface of the substrate change accordingly;

[0083] The smaller the jetting angle a and the smaller the curvature R of the surface of the substrate, the more suitable the printhead is for printing on a deep concave surface.

[0084] The relationship between a, W, L, and R in geometry can be used to guide the design of printhead structure size and jetting parameters.

[0085] At the same maximum effective flight distance L, the greater the width W of the inkjet printhead, the greater the jetting angle a and the greater the radius of curvature R, which is suitable for flat concave surfaces.

[0086] It should be noted that according to different application scenarios, the specific values of the above parameters can be adjusted according to actual needs; and the optimal values of different parameters can also be combined differently according to the effect, and are not limited to the above unique values. In other embodiments, in order to match the inkjet printhead 100 with more types of substrate 300 surfaces, the curvature type of the substrate 300 surface can also be divided into more types, and is not limited to being divided only into deep concave, medium concave and flat concave. Correspondingly, each concave type corresponds to a different curvature radius level, and there can be different curvature setting values, and the width of the inkjet printhead 100 can also have more levels of division.

[0087] The inkjet printhead 100 sets its width according to the different surface curvature radii of the substrate 300, making it easier for the printhead's jetting direction to align with the normal direction of the substrate 300's surface, thus avoiding collisions between the printhead and the substrate 300. This results in higher printing accuracy and stability on concave or multi-curvature surfaces. Specifically, when the curvature radius of the substrate 300's surface is less than a first set value, the substrate 300's surface is a deep concave surface. By setting the width of the inkjet printhead 100 to be no greater than the first width value, i.e., reducing the width of the printhead, the edge of its housing 110 avoids conflict with the protruding structures around the deep concave surface when the printhead approaches the substrate 300. The printhead can then get closer to the deep concave area, ensuring that the ink droplets 200 are ejected within the maximum effective jetting distance, thereby guaranteeing printing quality on deep concave surfaces. When the radius of curvature of the surface of the substrate 300 is between the first set value and the second set value, the surface of the substrate 300 is a medium concave surface. Therefore, the width of the inkjet printhead 100 can be appropriately increased to be between the first width value and the second width value. In this way, the inkjet printhead 100 is neither too wide nor too narrow, so that the cartridge 110 has enough ink volume, avoids frequent ink replacement, and improves the user experience.

[0088] Among them, such as Figure 4 As shown, in this embodiment, the two sides of the cartridge 110 along the jetting direction are inclined so that the extension lines of the two sides converge towards the maximum effective jetting point P. This forms an inclined conical structure in the cartridge 110. When the printhead approaches the surface of the substrate 300, the head of the conical structure will not touch the protruding structures around the concave surface of the substrate 300, allowing the printhead to approach the concave area and ensuring that the ink droplets 200 are jetted within the maximum effective jetting distance, thereby guaranteeing print quality.

[0089] Furthermore, in other embodiments, the included angle of inclination of the two sides is equal to the included jet angle. With this setting, when the printhead approaches the surface of the substrate 300, the distance between the printhead and the surface of the substrate 300 is ensured to be within the range of the maximum effective jet distance.

[0090] The inkjet printhead 100 of this embodiment has a wide range of compatible platforms and can be installed on devices such as robotic arms, 3D printers, and multi-axis linkage platforms to achieve synchronous printing and material deposition of complex curved surfaces.

[0091] Example 2

[0092] This embodiment provides an inkjet printhead array assembly 100, which includes multiple inkjet printheads 100 as described in Embodiment 1. By employing inkjet printheads 100 as described in Embodiment 1, this inkjet printhead array assembly can select different inkjet printheads 100 according to the different curvatures of the substrate 300 surface, thereby achieving higher printing accuracy and stability on concave or multi-curvature surfaces and adapting to the printing needs of irregular three-dimensional curved surfaces.

[0093] Furthermore, in this embodiment, the housing 110 of the multiple inkjet printheads 100 has a shape that matches the curvature of the substrate 300 at different printing positions. Such shapes include one or more combinations of elongated, circular, and polygonal shapes. Based on the different curved surfaces of the substrate 300's three-dimensional structure, these printheads of different shapes can be arranged into several small unit arrays according to the curvature variation rules to support multi-directional combinations. This allows the housing 110 shape to better adapt to the different curvature surfaces of the substrate 300, preventing collisions between the printheads and the substrate 300.

[0094] Example 3

[0095] This embodiment provides an inkjet printer, which includes an inkjet printhead 100 as described in Embodiment 1; or the inkjet printer includes an array assembly of inkjet printheads 100 as described in Embodiment 2. By using either the inkjet printhead 100 as described in Embodiment 1 or the inkjet printhead 100 array assembly as described in Embodiment 2, the inkjet printer can select different inkjet printheads 100 according to the different curvatures of the substrate 300 surface, thereby achieving higher printing accuracy and stability on concave or multi-curvature surfaces, and adapting to the printing needs of irregular three-dimensional curved surfaces.

[0096] Furthermore, such as Figure 6 As shown, in this embodiment, the jetting direction A of the nozzle 130 (i.e., the direction in which the arrow points to the substrate 300) is set to be consistent with the normal direction B of the surface of the substrate 300 (i.e., the direction in which the arrow points to the nozzle 130). This makes the jetting direction of the ink droplets 200 directly facing the surface of the substrate 300, which can reduce the error of the landing point of the ink droplets 200 to more than 30%, obtain higher precision deposition, and thus improve printing accuracy and quality.

[0097] Example 4

[0098] This embodiment provides an inkjet printing method, which includes the following steps:

[0099] S1. Detect the radius of curvature R of the surface of the substrate 300;

[0100] S2. Configure the inkjet printhead 100 according to the radius of curvature R, wherein,

[0101] When the curvature is less than the first set value, the surface of the substrate 300 is a deep concave surface, so the width W of the inkjet printhead 100 is reduced, and the jetting angle of the inkjet printhead 100 is reduced.

[0102] The jet angle is the angle formed by the maximum effective jet point P of the inkjet printhead 100 along the jet direction and the two sides of the cartridge 110 of the inkjet printhead 100 at their widest positions along the jet direction; the width W of the inkjet printhead 100 is the bottom width of the jet angle at the widest positions of the two sides of the cartridge 110.

[0103] Through the above steps, the inkjet printing method can configure the inkjet printhead 100 according to the different surface curvatures of the substrate 300, making it easier for the jetting direction of the printhead to be consistent with the normal direction of the surface of the substrate 300, avoiding collision between the printhead and the substrate 300, thereby achieving higher printing accuracy and stability on concave or multi-curvature surfaces. Specifically, when the radius of curvature R is less than a first set value, the surface of the substrate 300 is a deep concave surface. By reducing the width W of the inkjet printhead 100, the edge of its housing 110 is prevented from interfering with the raised structure around the deep concave surface of the substrate 300 when the printhead approaches the substrate 300. The printhead can then get closer to the deep concave surface area, ensuring that the ink droplets 200 are ejected within the maximum effective ejection distance. By reducing the ejection angle of the inkjet printhead 100, the degree to which the printhead approaches the surface of the substrate 300 can be increased (i.e., the distance from the nozzle 130 of the inkjet printhead 100 to the surface of the substrate 300 is shortened), further ensuring that the ink droplets 200 are ejected within the maximum effective ejection distance, thereby ensuring the printing quality on the deep concave surface.

[0104] When the radius of curvature R is less than the first set value, the width W of the inkjet printhead 100 is reduced to no more than the first width value, which is the preferred width range.

[0105] When the radius of curvature R is between a first set value and a second set value, the surface of the substrate 300 is moderately concave. Therefore, the inkjet printhead 100 is manufactured such that its width W is between a first width value and a second width value; the second set value is greater than the first set value, and the second width value is greater than the first width value. That is, when the surface of the substrate 300 is moderately concave, the width of the inkjet printhead 100 can be appropriately increased to be between the first width value and the second width value. This ensures that the inkjet printhead 100 is neither too wide nor too narrow, allowing the cartridge 110 to have sufficient ink volume, avoiding frequent ink changes, and improving the user experience.

[0106] Further, when the radius of curvature R is between the first set value and the second set value, the spray angle of the inkjet print head 100 can also be reduced. This can increase the degree of approach of the print head to the surface of the substrate 300 when printing on a medium concave surface, ensuring that the ink droplets 200 are sprayed within the maximum effective spray distance; thus ensuring the printing quality on the medium concave surface.

[0107] When the radius of curvature R is greater than the second set value, the surface of the substrate 300 is a gently concave curved surface or approximately a flat surface, and the spray angle of the inkjet print head 100 can be reduced. By reducing the spray angle, the degree of approach of the print head to the surface of the substrate 300 can be increased, ensuring that the ink droplets 200 are sprayed within the maximum effective spray distance; thus improving the printing quality.

[0108] The specific method of reducing the spray angle can be to increase the flight distance of the ink droplets 200, or to replace different cartridges 110 to adjust the angle between the print head chip 120 and the cartridge 110 to adapt to different curvature concave surfaces.

[0109] When the radius of curvature R is greater than the second set value, the width W of the inkjet print head 100 can also be increased, so that the cartridge 110 can carry more ink, and the ink replacement frequency can be reduced.

[0110] The preferred values of the above-mentioned parameters (i.e. the set values and the width values) are: the first set value is 8mm, the second set value is 15mm; the first width value is 5mm, and the second width value is 10mm. Similar to the case of Example 1, according to different application scenarios, the specific values of the above-mentioned parameters can be adjusted according to the actual effect as needed; and the preferred values of different parameters can also be combined differently according to the effect as needed, and are not limited to the above-mentioned unique values. In other embodiments, in order to match the inkjet print head 100 with more types of surfaces of the substrate 300, the curvature type of the surface of the substrate 300 can also be divided into more types, and is not limited to being divided only into deep concave surface, medium concave surface and gently concave surface. Correspondingly, each concave surface type corresponds to a different curvature radius level, and there can be different curvature radius set values, and the width of the inkjet print head 100 can also have more levels of division.

[0111] Further, the inkjet printing method also includes:

[0112] Detecting the radius of curvature R of the surface of the substrate 300 at different positions along the printing direction;

[0113] Selecting the inkjet print head 100 with a corresponding shape cartridge 110 according to the radius of curvature R at different positions; the shape of the cartridge 110 includes one or more combinations of a long strip shape, a circular shape, and a polygonal shape.

[0114] The inkjet printing method can switch the inkjet printheads 100 with different shapes of the cartridge 110 according to the surface of the print substrate 300 with different curvatures through the above steps. The combination of the different shapes of the cartridge 110 can better adapt to the different curved surfaces (for example, a three-dimensional curved surface structure) of the print substrate 300, thereby improving the printing precision and quality.

[0115] In the inkjet printing method, the ejection direction of the inkjet printhead 100 is set to be consistent with the normal direction of the surface of the print substrate 300. In this way, the ejection direction of the ink droplets 200 is perpendicular to the surface of the print substrate 300, which reduces the landing point error of the ink droplets 200, thereby improving the printing precision and quality.

[0116] Although the specific embodiments of the present application are described above, those skilled in the art should understand that this is only an example. The protection scope of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present application. These changes and modifications are also within the protection scope of the present application.

Claims

1. An inkjet printhead, the inkjet printhead comprising a cartridge containing ink and a printhead chip disposed on the cartridge, the printhead chip having nozzles formed thereon; characterized in that, The inkjet printhead is configured as follows: When the radius of curvature of the substrate surface is less than a first set value, the width of the inkjet printhead is not greater than the first width value, and the jetting angle of the inkjet printhead is reduced. When the radius of curvature of the substrate surface is between the first set value and the second set value, the width of the inkjet printhead is between the first width value and the second width value; the second set value is greater than the first set value, and the second width value is greater than the first width value; Wherein, the maximum effective ejection point of the ink droplet ejected from the nozzle along the ejection direction forms an ejection angle with the two sides of the cartridge along the ejection direction at the widest position, and the width of the inkjet printhead is the bottom width of the ejection angle at the widest position of the two sides of the cartridge.

2. The inkjet printhead as described in claim 1, characterized in that, The two sides of the box body along the spray direction are inclined so that the extension lines of the two sides converge towards the maximum effective spray point.

3. The inkjet printhead as described in claim 2, characterized in that, The included angle of inclination of the two sides is equal to the included angle of injection.

4. The inkjet printhead as described in claim 1, characterized in that, The first setting value is 8mm, and the second setting value is 15mm; And / or, the first width value is 5mm and the second width value is 10mm.

5. An inkjet printhead array assembly, characterized in that, The inkjet printhead array assembly includes a plurality of inkjet printheads as described in any one of claims 1-4.

6. The inkjet printhead array assembly as described in claim 5, characterized in that, The housing of the plurality of inkjet printheads has a shape that conforms to the curvature of the substrate at different printing positions.

7. An inkjet printer, characterized in that, The inkjet printer includes an inkjet printhead as described in any one of claims 1-4; or the inkjet printer includes an inkjet printhead array assembly as described in claim 5 or 6.

8. The inkjet printer as described in claim 7, characterized in that, The spray direction of the nozzle is set to be consistent with the normal direction of the substrate surface.

9. An inkjet printing method, characterized in that, The inkjet printing method includes the following steps: Detect the radius of curvature of the substrate surface; The inkjet printhead is configured according to the radius of curvature, wherein... When the radius of curvature is less than a first set value, the width of the inkjet printhead is reduced, and the jetting angle of the inkjet printhead is reduced. The jetting angle is the angle formed by the maximum effective jetting point of the inkjet printhead along the jetting direction and the two sides of the inkjet printhead housing at their widest positions along the jetting direction; the width of the inkjet printhead is the bottom width of the jetting angle at the widest positions of the two sides of the housing. When the radius of curvature is less than a first set value, the width of the inkjet printhead is reduced to no more than the first width value; The configuration of the inkjet printhead according to the radius of curvature further includes: When the radius of curvature is between the first set value and the second set value, the inkjet printhead is manufactured such that the width of the inkjet printhead is between the first width value and the second width value; the second set value is greater than the first set value, and the second width value is greater than the first width value.

10. The inkjet printing method as described in claim 9, characterized in that, The configuration of the inkjet printhead according to the radius of curvature further includes: When the radius of curvature is between the first set value and the second set value, the jet angle of the inkjet printhead is reduced.

11. The inkjet printing method as described in claim 9, characterized in that, The configuration of the inkjet printhead according to the radius of curvature further includes: When the radius of curvature is greater than the second set value, the jet angle of the inkjet printhead is reduced.

12. The inkjet printing method as described in claim 9, characterized in that, The inkjet printing method further includes: Detect the radius of curvature of the substrate surface at different locations along the printing direction; The inkjet printhead with the corresponding shape of the cartridge is selected according to the radius of curvature at different locations; the shape of the cartridge includes one or more combinations of elongated, circular, and polygonal shapes.

13. The inkjet printing method as described in claim 9, characterized in that, The inkjet printing method further includes setting the jetting direction of the inkjet printhead to be consistent with the normal direction of the substrate surface.

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