A method and apparatus for inkjet printing

Abstract

The application provides a method and device for inkjet printing. The method is applied to a printing device. N groups of ink ejection holes are arranged on a nozzle base plate of the printing device. The method comprises the following steps: controlling a center axis of a to-be-printed object to coincide with a center line of an i-th group of ink ejection holes; controlling the to-be-printed object and the i-th group of ink ejection holes to move relatively in a first direction; when the i-th group of ink ejection holes is located above the to-be-printed object, controlling the i-th group of ink ejection holes to eject ink onto the to-be-printed object, so as to complete printing of the i-th group of ink ejection holes; controlling the to-be-printed object and an i+j-th group of ink ejection holes to move relatively in a second direction, so that the center axis of the to-be-printed object coincides with a center line of the i+j-th group of ink ejection holes; controlling the to-be-printed object and the i+j-th group of ink ejection holes to move relatively along the first direction; when the i+j-th group of ink ejection holes is located above the to-be-printed object, controlling the i+j-th group of ink ejection holes to eject ink onto the to-be-printed object, so as to complete printing of the i+j-th group of ink ejection holes; and the first direction is perpendicular to the second direction. The printing effect can be improved by the method.

Description

TECHNICAL FIELD

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

[0002] Inkjet printing is a printing method that tiny black or color ink droplets are sprayed onto an object by inkjet.

[0003] At present, the commonly used inkjet printing technology is to realize printing by inkjet on the surface of a curved object. However, the size of the curved object varies greatly. When the curved object is large, the printing speed is slow and the requirement for the inkjet printing device is high, and the structure is relatively complex. When the curved object is small, the color ink matching is not accurate, and when the ink droplet is large, the printing image is not sharp.

[0004] Therefore, how to provide a technical scheme of an inkjet printing method with good printing effect becomes a technical problem to be solved. SUMMARY

[0005] Some embodiments of the present application aim to provide a method and device for inkjet printing. The technical scheme of the embodiments of the present application can improve the efficiency and printing effect of inkjet printing, and has wide adaptability.

[0006] In a first aspect, some embodiments of the present application provide a method for inkjet printing, applied to a printing device, n groups of nozzles are arranged side by side on a nozzle base plate of the printing device, comprising: controlling the center axis of a to-be-printed object to coincide with the center line of the i-th group of nozzles, wherein i is a positive integer, i∈[1, n), and n is a positive integer greater than or equal to 2; controlling the relative movement of the to-be-printed object and the i-th group of nozzles in a first direction, when the i-th group of nozzles is located above the to-be-printed object, controlling the i-th group of nozzles to spray ink onto the to-be-printed object to complete the printing of the i-th group of nozzles; controlling the relative movement of the to-be-printed object and the i+j-th group of nozzles in a second direction, so that the center axis of the to-be-printed object coincides with the center line of the i+j-th group of nozzles, wherein i+j is a positive integer, i+j∈[1, n], and j≠0; controlling the relative movement of the to-be-printed object and the i+j-th group of nozzles in the first direction, when the i+j-th group of nozzles is located above the to-be-printed object, controlling the i+j-th group of nozzles to spray ink onto the to-be-printed object to complete the printing of the i+j-th group of nozzles; wherein the first direction is perpendicular to the second direction.

[0007] Some embodiments of the present application can realize inkjet printing of a to-be-printed object by n groups of nozzles and the relative movement of the to-be-printed object and the nozzle base plate in the first direction, thereby improving the efficiency and printing effect of inkjet printing, and having wide adaptability.

[0008] In some embodiments, each of the i-th group of injection holes and the i+j-th group of injection holes comprises a plurality of groups of injection holes, and each of the plurality of groups of injection holes comprises a plurality of columns of injection holes.

[0009] In some embodiments, one physical injection head comprises a plurality of columns of injection holes, and the plurality of columns of injection holes are divided into a plurality of groups of injection holes, and the n groups of injection holes belong to the plurality of groups of injection holes.

[0010] In some embodiments, the diameter of the object to be printed is not greater than a set threshold value; or the object to be printed belongs to a first type set.

[0011] In some embodiments, each of the i-th group of injection holes belongs to the i-th column of injection heads, and each of the i+j-th group of injection holes belongs to the i+j-th column of injection heads.

[0012] In some embodiments, the N columns of injection heads are arranged side by side on the injection head base plate, each of the N columns of injection heads is provided with a plurality of injection heads along the first direction; the n groups of injection holes are selected from the N columns of injection heads, and N is a positive integer greater than 1.

[0013] The injection head of some embodiments of the present application can be flexibly set and has wide adaptability.

[0014] In some embodiments, the diameter of the object to be printed is greater than a set threshold value; or the object to be printed belongs to a second type set.

[0015] In some embodiments, the method further comprises: when the number of objects to be printed is M, M n groups of injection holes are arranged on the injection head base plate, and each of the n groups of injection holes corresponds to one object to be printed, wherein M≥2.

[0016] Some embodiments of the present application can realize simultaneous printing and improve printing efficiency by printing M objects to be printed through M n groups of injection holes.

[0017] In some embodiments, the object to be printed is a curved surface object such as a cylinder or a cone, and in the printing process, the object to be printed is controlled to perform a continuous rotation motion around its own central axis.

[0018] In a second aspect, some embodiments of the present application provide an inkjet printing device applied to a printing device, wherein a plurality of n groups of nozzles are arranged side by side on a nozzle plate of the printing device, and the device comprises: a first control module configured to control a center axis of a to-be-printed object to coincide with a center line of an i-th group of nozzles, wherein i is a positive integer, i∈[1, n), and n is a positive integer greater than or equal to 2; a second control module configured to control relative movement of the to-be-printed object and the i-th group of nozzles in a first direction, and when the i-th group of nozzles is located above the to-be-printed object, control the i-th group of nozzles to spray ink onto the to-be-printed object to complete printing of the i-th group of nozzles; a third control module configured to control relative movement of the to-be-printed object and an i+j-th group of nozzles in a second direction, so that the center axis of the to-be-printed object coincides with a center line of the i+j-th group of nozzles, wherein i+j is a positive integer, i+j∈[1, n], and j≠0; and a fourth control module configured to control relative movement of the to-be-printed object and the i+j-th group of nozzles in the first direction, and when the i+j-th group of nozzles is located above the to-be-printed object, control the i+j-th group of nozzles to spray ink onto the to-be-printed object to complete printing of the i+j-th group of nozzles, wherein the first direction is perpendicular to the second direction.

[0019] In a third aspect, some embodiments of the present application provide a computer readable storage medium having stored thereon a computer program, wherein the program, when executed by a processor, can implement the method according to any one of the embodiments of the first aspect.

[0020] In a fourth aspect, some embodiments of the present application provide an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, can implement the method according to any one of the embodiments of the first aspect.

[0021] In a fifth aspect, some embodiments of the present application provide a computer program product, comprising a computer program, wherein the computer program, when executed by a processor, can implement the method according to any one of the embodiments of the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of some embodiments of the present application, the following will briefly introduce the drawings needed to be used in some embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0023] Figure 1 One of the inkjet printing method flowcharts provided by some embodiments of the present application;

[0024] Figure 2 One of the schematic diagrams of inkjet printing structure provided for some embodiments of the present application;

[0025] Figure 3 One of the schematic diagrams of inkjet printing structure provided for some embodiments of the present application;

[0026] Figure 4 One of the schematic diagrams of inkjet printing structure provided for some embodiments of the present application;

[0027] Figure 5 One of the schematic diagrams of inkjet printing structure provided for some embodiments of the present application;

[0028] Figure 6 One of the schematic diagrams of inkjet printing structure provided for some embodiments of the present application;

[0029] Figure 7 One of the schematic diagrams of inkjet printing structure provided for some embodiments of the present application;

[0030] Figure 8 One of the schematic diagrams of inkjet printing structure provided for some embodiments of the present application;

[0031] Figure 9 One of the schematic diagrams of inkjet printing structure provided for some embodiments of the present application;

[0032] Figure 10 One of the schematic diagrams of inkjet printing structure provided for some embodiments of the present application;

[0033] Figure 11 One of the schematic diagrams of inkjet printing structure provided for some embodiments of the present application; DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

[0035] It should be noted that similar reference numerals and letters refer to similar items in the following drawings, and therefore, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings. Meanwhile, in the description of the present application, the terms "first", "second", etc. are only used to distinguish description, and cannot be understood as indicating or implying relative importance.

[0036] A device for printing graphics on the surface of a candle is provided in the related art. The device includes an inkjet printing unit, which includes a printing support, a print head arranged on the printing support, the print head being capable of linear reciprocating motion relative to the support, two mutually parallel rotating shafts arranged below the inkjet printing unit, at least one rotating shaft being coupled to a driving device, and a circuit board connected to the driving device and the inkjet printing unit. The candle to be printed is placed on the two mutually parallel rotating shafts. Since the device does not have a pressing mechanism, the driving force of the candle during rotation is insufficient. During the printing process, the rotating shafts drive the candle to step rotate, and the print head reciprocates to spray ink droplets onto the surface of the candle. The printing speed is slow, and the printing efficiency is low. Based on the problems of the prior art, the applicant continuously updates and iterates the printing device, and develops a printing device with better printing function (for details, refer to the patent applications with the application numbers 201280073471.4, 201420072119.5, 201410769416.X, etc.). The applicant found in the research that although the existing printing device can meet the daily demand, the existing inkjet printing device for the surface of a cylinder using inkjet printing technology either has a slow printing speed and low efficiency, or has a complex structure, occupies a large space, and has a high cost. Moreover, when the diameter of the object to be printed is small, the color matching of different ink is not accurate; when the ink droplet is large, the sharpening degree of the printed graphics is not high. Therefore, the existing printing method cannot meet the printing of small-diameter curved surface objects with high sharpening effect graphics, and cannot adapt to more extensive individual customization needs.

[0037] Therefore, some embodiments of the present application provide an inkjet printing method applied to a printing device, a plurality of groups of nozzles are arranged side by side on a nozzle base plate of the printing device, and different groups of nozzles can print an object to be printed by controlling the positional relationship and relative motion between the center axis of the object to be printed and the nozzles. Some embodiments of the present application can improve the printing effect while reducing the structural complexity and space occupation of the printing device. Moreover, the method is suitable for various types of curved surface objects, can meet the printing of small-diameter curved surface objects with high sharpening effect graphics, and can adapt to more extensive individual customization needs.

[0038] The following will be described in conjunction with the accompanying drawings Figure 1 The implementation process of the inkjet printing performed by the printing device according to some embodiments of the present application is exemplarily described. The nozzle base plate of the printing device has n groups of nozzles arranged side by side.

[0039] As Figure 1As shown, some embodiments of this application provide a flowchart of an inkjet printing method, which includes at least: S110, controlling the central axis of the object to be printed to coincide with the center line of the i-th group of nozzles, where i is a positive integer, i∈[1,n), and n is a positive integer ≥2. S120, controlling the object to be printed and the i-th group of nozzles to move relative to each other in a first direction, and when the i-th group of nozzles is above the object to be printed, controlling the i-th group of nozzles to eject ink onto the object to be printed to complete the printing of the i-th group of nozzles; S130, controlling the object to be printed and the (i+j)-th group of nozzles to move relative to each other in a second direction, so that the central axis of the object to be printed coincides with the center line of the (i+j)-th group of nozzles, where i+j is a positive integer, i+j∈[1,n], j≠0, and n is a positive integer ≥2. S140, control the object to be printed and the i+j group of nozzles to move relative to each other along the first direction (i.e., return relative movement), when the i+j group of nozzles is above the object to be printed, control the i+j group of nozzles to spray ink onto the object to be printed, so as to complete the printing of the i+j group of nozzles; wherein, the first direction is perpendicular to the second direction.

[0040] Taking the XY coordinate system as an example, the Y-axis is the first direction and the X-axis is the second direction. The first direction in S120 can be the +Y-axis direction, and the first direction in S140 can be either the -Y-axis direction or the +Y-axis direction. The specific direction of motion can be flexibly adjusted according to the actual situation, and this embodiment does not impose specific limitations here. For ease of explanation, the first direction in the following text refers to the +Y-axis direction, and the return direction of the first direction refers to the -Y-axis direction.

[0041] For example, in some embodiments of this application, after the printing device controls the centerline of the object to be printed and the i-th group of nozzles to coincide, it controls the object to be printed and the i-th group of nozzles to move relative to each other in the +Y axis direction, so that the i-th group of nozzles performs inkjet printing. Then, by moving the object to be printed in the second direction so that its central axis coincides with the centerline of the (i+j)-th group of nozzles, the object to be printed and the (i+j)-th group of nozzles can move relative to each other in the -Y axis direction, completing the inkjet printing of the (i+j)-th group of nozzles.

[0042] It should be noted that the number of relative movements between the object to be printed and the nozzle in the first direction depends on the number of printing passes required to complete the printing of the object. Understandably, when n=2, printing the object can be completed by executing S110~S140 once. When n>2, the values ​​of i and j can be any value in [1, n), and during the loop, the value of i+j belongs to [1, n]. By repeating the above S110~S140 operation steps, i and j can obtain all values ​​throughout the printing process, that is, reciprocating motion in the first and second directions until the printing of the object is completed.

[0043] Alternatively, either the object to be printed or the printhead base plate can remain in motion in the first direction, so that they are in a state of relative motion. Movement in the second direction can also be achieved through relative motion between the object to be printed and the printhead base plate; this embodiment of the application does not specifically limit this.

[0044] In some embodiments of this application, the object to be printed is a cylinder, a cone, or an irregular cylindrical / conical curved surface object. During the printing process, the object to be printed is controlled to rotate continuously around its own central axis.

[0045] For example, in some embodiments of this application, the object to be printed can be various types of curved objects, such as pencils, pen tubes, eyebrow pencils, lipstick tubes, etc. When printing, the object is fixedly mounted on a fixture so that it can be driven to continuously rotate around its own rotational central axis (hereinafter referred to as the central axis). That is, while the object and the nozzle are engaged in inkjet printing, the object is always in a state of rotation.

[0046] In some embodiments of this application, both the i-th group of nozzles and the (i+j)-th group of nozzles include multiple groups of nozzles, and each group of nozzles includes multiple rows of nozzles.

[0047] For example, in some embodiments of this application, the i-th group of nozzles and the (i+j)-th group of nozzles are both composed of multiple groups of nozzles. Each group of nozzles contains multiple rows of nozzles, and each row of nozzles has a row of multiple circular inkjet nozzles arranged along a straight line.

[0048] The following section illustrates the implementation process of the inkjet printing method by taking into account different arrangements of the nozzles on the printhead base plate.

[0049] Example 1

[0050] In some embodiments of this application, a physical nozzle includes multiple rows of nozzles, which are divided into multiple groups of nozzles, and the n groups of nozzles belong to the multiple groups of nozzles.

[0051] Specifically, in one embodiment, when n=2, each group of nozzles consists of two rows of nozzles; the two rows of nozzles in the first group and the two rows of nozzles in the second group belong to the same nozzle head, and at least one nozzle head is provided on the nozzle head base plate along the first direction, with the nozzle length direction of the nozzle head being parallel to the first direction.

[0052] For example, such as Figure 2 The schematic diagram of the inkjet printing structure shown uses the XY-axis coordinate system as an example. The positive and negative directions of the X-axis are the second direction, and the positive and negative directions of the Y-axis are the first direction. When the outward direction of the first direction is the positive direction of the Y-axis, the return direction of the first direction is the negative direction of the Y-axis. Above the object to be printed 0 is a printhead mounted on the printhead base plate (the center line of the object to be printed 0 is its rotation center axis). Four rows of nozzles, A, B, C, and D, are distributed sequentially on this printhead, each row containing several circular inkjet nozzles. A and B belong to the first group of nozzles, with their center line L1; C and D belong to the second group of nozzles, with their center line L2; the center line between B and C is L3; the distance between A and B, and between C and D, is less than the distance between B and C.

[0053] Understandable Figure 2 The nozzle base plate is provided with only one nozzle to facilitate the explanation of the arrangement of each row of nozzles. The number of nozzles can be set as needed, and this application embodiment does not make a specific limitation.

[0054] To improve the printing effect on objects, in some embodiments of this application, the diameter of the object to be printed is not greater than a set threshold; or, if the object to be printed belongs to the first type set, it is confirmed that the object to be printed is a small-diameter curved surface object, in which case the following can be used: Figure 2 The process shown is to print using the first and second sets of nozzles respectively, in order to solve the problem that the distance between the curved surface of a small-diameter object and each set of nozzles is relatively large, which affects the position of the ink droplets, causing misregistration of the printed image and affecting the printing quality.

[0055] In practical applications, users can select the printing mode for the object to be printed on the printer, such as how many sets of nozzles are needed, the arrangement of the nozzles, etc., so that the printer can perform inkjet printing on objects of different types and sizes, making it highly adaptable.

[0056] The following example illustrates the printing process for small-diameter curved surfaces.

[0057] Please see the appendix Figure 3 Printed diagram, Figure 3There are three nozzles in the Y direction of the nozzle base plate. The length of the nozzle of each nozzle is parallel to the Y direction. The three nozzles are arranged at intervals, namely the first nozzle 1, the second nozzle 2 and the third nozzle 3. The three nozzles need to print the object 4 to be printed.

[0058] It is understandable that the first nozzle 1, the second nozzle 2, and the third nozzle 3 each contain four rows of nozzles. The A and B rows of nozzles from the first nozzle 1, the second nozzle 2, and the third nozzle 3 form the first group of nozzles; this first group contains three sets of nozzles: the A and B rows of nozzles from the first nozzle 1, the second nozzle 2, and the third nozzle 3. Similarly, the C and D rows of nozzles from the first nozzle 1, the second nozzle 2, and the third nozzle 3 form the second group of nozzles, which contains the C and D rows of nozzles from the three nozzles.

[0059] Specifically, the nozzles in columns A and B of the first printhead 1 print pretreatment ink P, and the nozzles in columns C and D of the first printhead 1 print magenta ink M; the nozzles in columns A and B of the second printhead 2 print white ink W, and the nozzles in columns C and D of the second printhead 2 print cyan ink C; the nozzles in columns A and B of the third printhead 3 print yellow ink Y, and the nozzles in columns C and D of the third printhead 3 print black ink K.

[0060] During the printing stage, the object to be printed 4 is placed on the fixed fixture, and the central axis of the object to be printed 4 is controlled to coincide with the projection of the center line L1 between the first group of nozzles, that is, the nozzles in column A and column B. Specifically, as follows: Figure 3 As shown in (a). After printing begins, the printhead base plate is defined as being in its initial position. The printhead base plate drives the first printhead 1, the second printhead 2, and the third printhead 3 to move towards the object to be printed 4 along the +Y direction (i.e., the first direction). When the first printhead 1 passes over the printing area on the surface of the object to be printed 4, the A-column and B-column nozzles of the first printhead 1 spray pre-treatment ink P. Then, the second printhead 2 enters above the printing area, and the A-column and B-column nozzles of the second printhead 2 spray white ink W. Then, the third printhead 3 enters above the printing area, and the A-column and B-column nozzles of the third printhead 3 spray yellow ink Y. This continues until the end of the third printhead 3 leaves the object to be printed 4 and reaches the endpoint position in the Y-axis direction. The first pass of printing is completed (i.e., the first set of nozzles is completed). At this time, the positions of the printhead and the object to be printed 4 are as follows. Figure 3 As shown in (b).

[0061] Next, control the object to be printed 4 to move to the right along the X direction, so that the central axis of the object to be printed 4 coincides with the projection of the center line L2 between the nozzles in column C and column D, as shown. Figure 3As shown in (c). Then, the printhead base plate drives the printhead to move along the -Y direction (that is, the return direction of the first direction, the negative Y-axis) towards the object to be printed 4. When passing the printing area on the surface of the object to be printed 4, firstly, the third printhead 3 enters above the printing area, and the C and D columns of the third printhead 3 spray black ink K; then the second printhead 2 enters above the printing area, and the C and D columns of the second printhead 2 spray cyan ink C; finally, the first printhead 1 enters above the printing area, and the C and D columns of the first printhead 1 spray magenta ink M, until the end of the first printhead 1 leaves the printing area and reaches the initial position in the Y-axis direction, as shown. Figure 3 As shown in (d), the second printing is now complete (that is, the second set of nozzles is now printed), and the object to be printed, 4, is now printed.

[0062] It should be noted that, Figure 3 The number of printheads shown is merely a specific example. In practical applications, different numbers of printheads can be set on the printhead base plate according to the size of the object to be printed or other requirements. It should be understood that the embodiments of this application are not limited to this. For example, as... Figure 4 The diagram shows a first nozzle 11, a second nozzle 12, a third nozzle 13, and a fourth nozzle 14 mounted on a nozzle base plate; for example, such as... Figure 5 The illustration shows a first printhead 111, a second printhead 112, a third printhead 113, a fourth printhead 114, and a fifth printhead 115 arranged on the printhead base plate. The ink color in each row of nozzles within the different printheads can be set as needed; this embodiment does not impose specific limitations here.

[0063] Understandable Figure 4 and Figure 5 The principle of inkjet printing and Figure 3 The principle is the same, the difference being that besides the number of printheads, the color of the ink in the nozzles may also differ. When any printhead contains transparent ink V in its nozzle, that printhead needs to perform inkjet printing on the object to be printed last.

[0064] The following is based on Figure 4 The printing process of the object to be printed is illustrated using the four nozzles shown as examples.

[0065] like Figure 4As shown, the object to be printed (not shown) is located above the first printhead 11. The printhead base plate is equipped with the first printhead 11, the second printhead 12, the third printhead 13, and the fourth printhead 14 along the Y direction. Specifically, the A and B columns of the first printhead 11 print pretreatment ink P, the C and D columns of the first printhead 11 print yellow ink Y, the A and B columns of the second printhead 12 print white ink W, the C and D columns of the second printhead 12 print magenta ink M, the A and B columns of the third printhead 13 print white ink W, the C and D columns of the third printhead 13 print cyan ink C, the A and B columns of the fourth printhead 14 print transparent ink V, and the C and D columns of the fourth printhead 14 print black ink K.

[0066] Specific Figure 4 The printing principle is the same as in Embodiment 1 above. First, the center axis of the object to be printed is aligned with the center line between the straight line where column A nozzles and column B nozzles are located. The printhead base plate moves along the +Y axis direction. The column A nozzles and column B nozzles of the first printhead 11 print pretreatment ink P, the column A nozzles and column B nozzles of the second printhead 12 print white ink W, and the column A nozzles and column B nozzles of the third printhead 13 print white ink W, thus completing the printing of pretreatment ink and white ink. Next, the central axis of the object to be printed is aligned with the center line between the lines containing the C and D columns of nozzles along the X-axis. Then, the printhead base plate moves along the -Y direction. The C and D columns of the fourth printhead 14 print black ink (K), the C and D columns of the third printhead 13 print cyan ink (C), the C and D columns of the second printhead 12 print magenta ink (M), and the C and D columns of the first printhead 11 print yellow ink (Y), completing the ink application for the colored inks. Then, the central axis of the object to be printed is aligned with the center line between the lines containing the A and B columns of nozzles along the X-axis. The printhead base plate moves along the Y-axis, and the A and B columns of the fourth printhead 14 print transparent ink (V) as they pass through the desired area of ​​the image on the object. When the printhead base plate reaches the end position on the Y-axis, the printing operation for this object is completed.

[0067] The following is based on Figure 5 The printing process of the object to be printed is illustrated using the five printheads shown as examples. This embodiment is similar to the one described above. Figure 4 The difference in the embodiment is that it requires five nozzles to print on the small-diameter object to be printed.

[0068] like Figure 5As shown, a first printhead 111, a second printhead 112, a third printhead 113, a fourth printhead 114, and a fifth printhead 115 are sequentially arranged along the negative Y-axis. Specifically, the A and B columns of the first printhead 111 print pretreatment ink P, the C and D columns of the first printhead 111 print spot color ink S1, the A and B columns of the second printhead 112 print white ink W, and the C and D columns of the second printhead 112 print yellow ink. Y, the nozzles in columns A and B of the third printhead 113 print white ink W, the nozzles in columns C and D of the third printhead 113 print magenta ink M, the nozzles in columns A and B of the fourth printhead 114 print transparent ink V, the nozzles in columns C and D of the fourth printhead 114 print cyan ink C, the nozzles in columns A and B of the fifth printhead 115 print transparent ink V, and the nozzles in columns C and D of the fifth printhead 115 print black ink K.

[0069] The specific printing working principle is similar to the above embodiment. First, the rotation center axis of the object to be printed is aligned with the center line between the straight line where column A nozzles and column B nozzles are located. The printhead base plate moves along the Y-axis. The column A nozzles and column B nozzles of the first printhead 111 print pretreatment ink P, the column A nozzles and column B nozzles of the second printhead 112 print white ink W, and the column A nozzles and column B nozzles of the third printhead 113 print white ink W, thus completing the printing of pretreatment ink and white ink. Next, the rotation center axis of the object to be printed is controlled along the X-axis to coincide with the center line between the straight lines containing the C and D columns of nozzles. Then, the printhead base plate moves along the negative Y-axis. The C and D columns of the fifth printhead 115 print black ink K, the C and D columns of the fourth printhead 114 print cyan ink C, the C and D columns of the third printhead 113 print magenta ink M, the C and D columns of the second printhead 112 print yellow ink Y, and the C and D columns of the first printhead 111 print spot color ink S1, thus completing the ink application of the colored inks. Then, along the X-axis, the rotation center axis of the object to be printed is controlled to coincide with the center line between the straight lines where the A-column nozzles and the B-column nozzles are located. Then, the printhead base plate moves along the Y-axis. The A-column nozzles and B-column nozzles of the fifth printhead 115 and the A-column nozzles and B-column nozzles of the fourth printhead 114 print transparent ink V as they pass through the area required for the image. When the printhead base plate moves to the end position of the Y-axis, the printing operation of the object to be printed is completed.

[0070] Example 2

[0071] To improve the printing effect on objects, in some embodiments of this application, the diameter of the object to be printed is greater than a set threshold; or, if the object to be printed belongs to the second type set, it is confirmed that the object to be printed is a large-diameter curved surface object, and in this case, it can be printed according to... Figure 6The printheads are arranged in a specific way to print, thereby saving printhead space while improving print quality.

[0072] In some embodiments of this application, N columns of nozzles are arranged side by side on the nozzle base plate in the second direction; each column of the N columns of nozzles is provided with multiple nozzles along the first direction, the length direction of the nozzle orifice of each nozzle is parallel to the Y direction, and adjacent nozzles are arranged with their ends spaced apart; the n sets of nozzles are predetermined from the N columns of nozzles, where N is a positive integer greater than 1.

[0073] For example, in some embodiments of this application, such as Figure 6 The nozzle base plate shown has N=2 rows of nozzles arranged side by side in the Y direction. Each row of nozzles has three nozzles: the first row has first nozzle 21, second nozzle 22, and third nozzle 23; the second row has fourth nozzle 24, fifth nozzle 25, and sixth nozzle 26. Each nozzle can be equipped with two or four rows of nozzles.

[0074] In one implementation, each group of nozzles in the i-th group belongs to the i-th column of nozzles, and each group of nozzles in the (i+j)-th group belongs to the (i+j)-th column of nozzles.

[0075] For example, when each printhead has two or four rows of nozzles, and n=2, the first group of nozzles can refer to the group consisting of the nozzles in the first printhead 21, the second printhead 22, and the third printhead 23. The second group of nozzles can refer to the group consisting of the nozzles in the fourth printhead 24, the fifth printhead 25, and the sixth printhead 26. That is, one row of printheads constitutes one group of nozzles. Similarly, when N=3, there are 3 rows of printheads, or 3 groups of nozzles, on the printhead base plate. In this case, the two groups of nozzles when n=2 can be pre-selected from these 3 groups, i.e., any two columns from the 3 columns are pre-selected for printing. Therefore, n≤N. The specific selection method can be flexibly chosen according to the object to be printed, and this embodiment does not impose specific limitations here.

[0076] In another implementation, when each nozzle has four rows of nozzles, Figure 6 There are a total of 4 groups of nozzles: the first group consists of columns A and B of nozzles from the first nozzle 21, the second nozzle 22, and the third nozzle 23; the second group consists of columns C and D of nozzles from the first nozzle 21, the second nozzle 22, and the third nozzle 23; the third group consists of columns A and B of nozzles from the fourth nozzle 24, the fifth nozzle 25, and the sixth nozzle 26; and the fourth group consists of columns C and D of nozzles from the fourth nozzle 24, the fifth nozzle 25, and the sixth nozzle 26. n groups (e.g., two or three groups of nozzles when n = 2 or 3) can be randomly selected from these 4 groups of nozzles (i.e., two columns of nozzles). Therefore, n ≤ 2N.

[0077] It should be understood that the value of N on the printhead base plate of this application is quite flexible. In addition to the two columns listed, it can also be three, four, or more columns. When moving in the X direction, it is not limited to moving between two adjacent columns of printheads or two adjacent groups of nozzles. It can jump from the first group of printheads (or nozzles) to the third, fourth, fifth, etc., using various random combinations for printing. In other words, which group of printheads or which column of printheads to use can be flexibly set according to needs, that is, ink can be applied in different orders according to the needs of the scenario (for example, printing different flavors of traditional Chinese medicine).

[0078] The following is combined Figure 6 The nozzle arrangement exemplifies the printing process for large-diameter curved objects. This embodiment includes two sets of nozzles: the first set of nozzles consists of the first nozzle 21, the second nozzle 22, and the third nozzle 23; the second set of nozzles consists of the fourth nozzle 24, the fifth nozzle 25, and the sixth nozzle 26.

[0079] Specifically, let's take an example where each printhead contains four rows of printheads: A, B, C, and D. The first printhead 21 prints pretreatment ink P through its four rows of nozzles; the second printhead 22 prints white ink W through its four rows of nozzles; and the third printhead 23 prints transparent ink V through its four rows of nozzles. The fourth printhead 24 prints light cyan ink Lc through its A and B rows of nozzles, and light red ink Lm through its C and D rows of nozzles. The fifth printhead 25 prints magenta ink M through its A and B rows of nozzles, and yellow ink Y through its C and D rows of nozzles. The sixth printhead 26 prints black ink K through its A and B rows of nozzles, and cyan ink C through its C and D rows of nozzles.

[0080] In the initial printing stage, the object to be printed 5 is placed on the fixed fixture, and the central axis of the object to be printed 5 is aligned with the projection of the center line L3 of the first printhead 21, the second printhead 22, and the third printhead 23. Figure 6 As shown in (a). After printing begins, the printhead base plate moves the printhead along the +Y direction closer to the object to be printed 5. First, the first printhead 21 enters above the printing area of ​​the object 5, and the four columns of nozzles of the first printhead 21 spray pre-treatment ink P. Then, the second printhead 22 enters above the printing area, and the four columns of nozzles of the second printhead 22 spray white ink W. Then, the third printhead 23 enters above the printing area, and the four columns of nozzles of the third printhead 23 do not spray ink. The first printhead 21, the second printhead 22, and the third printhead 23 pass above the printing area in sequence until the end of the third printhead 23 leaves the printing area and reaches the endpoint position in the Y-axis direction. The first pass of printing is completed. At this time, the positions of the printhead and the object 5 to be printed are as shown. Figure 6 As shown in (b).

[0081] Next, control the object to be printed 5 to move relative to the printhead base plate along the X-axis, and the position after movement is as follows: Figure 6 As shown in (c), the central axis of the object to be printed 5 coincides with the projection of the center line L4 of the fourth printhead 24, the fifth printhead 25, and the sixth printhead 26. Then, the printhead base plate moves the six printheads along the -Y direction towards the object to be printed 5. When passing the printing area on the surface of the object 5, the sixth printhead 26 first enters above the printing area, and its four nozzles spray black ink K and cyan ink C; then the fifth printhead 25 enters above the printing area, and its four nozzles spray magenta ink M and yellow ink Y; then the fourth printhead 24 enters above the printing area, and its four nozzles spray light red ink Lm and light cyan ink Lc, until the end of the fourth printhead 24 leaves the printing area and reaches its initial position in the Y-axis direction, as shown... Figure 6 As shown in (d), the second printing pass is complete. Next, the object to be printed 5 and the printhead base plate undergo a slight relative movement along the X-axis until the central axis of the object to be printed 5 coincides with the projection of L3, as shown... Figure 6 As shown in (e), the printhead base plate then moves its six printheads along the +Y direction towards the object 5 to be printed. When passing the printing area on the surface of the object 5, as the third printhead 23 enters above the printing area, the four rows of nozzles of the third printhead 23 spray transparent ink V, while the other printheads do not spray ink. The printhead base plate then moves to its final position, as shown in (e). Figure 6 (f) Thus, the printing of object 5 in this embodiment is completed.

[0082] It should be noted that the number of nozzle rows N on the nozzle base plate can be set according to actual needs, and the number of nozzles in each row can also be set as required. For example, Figure 6 In this embodiment, there are three nozzles per row; however, in other embodiments, there may be four, five, or other types of nozzles per row. For example, ... Figure 7 As shown, two columns are arranged side by side along the Y-axis. The first column has four printheads (i.e., first printhead 31, second printhead 32, third printhead 33, and fourth printhead 34), and the second column has three printheads (i.e., fifth printhead 35, sixth printhead 36, and seventh printhead 37). That is to say, the number of printheads and the ink color in each column can be the same or different, and this embodiment does not make specific limitations here.

[0083] For ease of understanding, the following is in conjunction with the appendix. Figure 7 This example illustrates the specific process of inkjet printing when two columns are configured with different numbers of printheads. This embodiment includes two sets of nozzles: the first set of nozzles consists of the first printhead 31, the second printhead 32, the third printhead 33, and the fourth printhead 34; the second set of nozzles consists of the fifth printhead 35, the sixth printhead 36, and the seventh printhead 37.

[0084] For large-diameter objects to be printed, it is necessary to Figure 7 The seven nozzles shown are... Figure 7 It can be seen that the nozzle base plate is arranged in two rows along the Y-axis, with four nozzles in the first row and three nozzles in the second row. The first row is arranged in sequence along the negative Y-axis as the first nozzle 31, the second nozzle 32, the third nozzle 33 and the fourth nozzle 34; the second row is arranged in sequence along the negative Y-axis as the fifth nozzle 35, the sixth nozzle 36 and the seventh nozzle 37. Specifically, the four columns of nozzles of the first printhead 31 print pretreatment ink P; the four columns of nozzles of the second printhead 32 print white ink W; the A and B columns of nozzles of the third printhead 33 print spot color ink S1; the C and D columns of nozzles of the third printhead 223 print spot color ink S2; the four columns of nozzles of the fourth printhead 34 print transparent ink V; the A and B columns of nozzles of the fifth printhead 25 print light cyan ink Lc; the C and D columns of nozzles of the fifth printhead 25 print light red ink Lm; the A and B columns of nozzles of the sixth printhead 26 print magenta ink M; the C and D columns of nozzles of the sixth printhead 26 print yellow ink Y; the A and B columns of nozzles of the seventh printhead 27 print black ink K; and the C and D columns of nozzles of the seventh printhead 27 print cyan ink C.

[0085] The specific inkjet printing principle is similar to that of the method embodiment provided above. When the printhead base plate passes over the object to be printed for the first time, the four rows of nozzles of the first printhead 31, the second printhead 32, and the third printhead 33 all spray ink; after the object to be printed moves along the X-axis for the first time, the four rows of nozzles of the seventh printhead 37, the sixth printhead 36, and the fifth printhead 35 all spray ink; finally, after the object to be printed moves along the X-axis for the second time, the four rows of nozzles of the fourth printhead 34 finally spray transparent ink, completing the printing.

[0086] For ease of understanding, the following is an appendix. Figure 8 Exemplary description will Figure 6 The specific process of inkjet printing after replacing the transparent ink with spot color ink.

[0087] like Figure 8As shown, this large-diameter object to be printed also requires six printheads. Three printheads are arranged along the Y-axis in two columns. The first column, along the negative Y-axis, consists of the first printhead 211, the second printhead 222, and the third printhead 223. The second column, along the negative Y-axis, consists of the fourth printhead 224, the fifth printhead 225, and the sixth printhead 226. Specifically, the four columns of nozzles of the first printhead 221 print pretreatment ink P; the four columns of nozzles of the second printhead 222 print white ink W; the A and B columns of nozzles of the third printhead 223 print spot color ink S1; the C and D columns of nozzles of the third printhead 223 print spot color ink S2; the A and B columns of nozzles of the fourth printhead 224 print light cyan ink Lc; the C and D columns of nozzles of the fourth printhead 224 print light red ink Lm; the A and B columns of nozzles of the fifth printhead 225 print magenta ink M; the C and D columns of nozzles of the fifth printhead 225 print yellow ink Y; the A and B columns of nozzles of the sixth printhead 226 print black ink K; and the C and D columns of nozzles of the sixth printhead 226 print cyan ink C.

[0088] Specifically, in the inkjet printing process described above Figure 6 The related embodiments shown are similar, except that when the first printhead 211, the second printhead 222 and the third printhead 223 pass over the object to be printed in sequence, the nozzle of the third printhead 223 also sprays spot color ink droplets at the same time. Therefore, the printing job can be completed by the printhead base plate and the object to be printed moving relative to each other twice in the Y direction.

[0089] It should be understood that regardless of the number of printhead columns, the number of printheads in each column, or the number of nozzles in each printhead, the printing principle remains the same. Figure 6 The principle is the same. Similarly, nozzles containing transparent ink need to be aligned with the central axis of the object to be printed and the corresponding center line before ink is sprayed individually through relative motion. If there is no transparent ink, ink can be sprayed sequentially according to the process described in the above embodiment, following the relative motion. In practical applications, nozzles containing transparent ink can be used as a separate group of nozzles or grouped with other nozzles; this application does not impose specific limitations on this.

[0090] In some embodiments of this application, the inkjet printing method may further include: when the number of objects to be printed is M, M sets of n nozzles are provided on the printhead base plate, and each set of n nozzles corresponds to printing one object to be printed, wherein M≥2.

[0091] For example, in some embodiments of this application, multiple objects to be printed can be printed simultaneously. Specifically, one object to be printed corresponds to one set of n nozzles. The printing device selects the required n sets of nozzles for each object to be printed, and then fixes each object to be printed on the corresponding fixture, so that the n sets of nozzles can print on the object. The printing principle can be referred to the method embodiments provided above, and will not be repeated here to avoid repetition.

[0092] The following is in conjunction with the appendix Figure 9 The present application provides an exemplary embodiment of an inkjet printing process performed by a printing device.

[0093] Please see the appendix Figure 9 , Figure 9 A flowchart of an inkjet printing method provided for some embodiments of this application.

[0094] The inkjet printing process is illustrated below.

[0095] S901, the object to be printed is fixedly mounted on the fixture and driven to rotate continuously around its own central axis.

[0096] S902, control the central axis of the object to be printed to coincide with the center line of the i-th group of nozzles.

[0097] S903, control the relative movement between the object to be printed and the i-th group of nozzles in the first direction, and when the i-th group of nozzles is above the object to be printed, control the i-th group of nozzles to spray ink onto the object to be printed.

[0098] S904, control the relative movement of the object to be printed and the i+j group of nozzles in the second direction, with the central axis of the object to be printed coinciding with the center line of the i+j group of nozzles.

[0099] S905, control the object to be printed and the i+j group of nozzles to move relative to each other in the first direction. When the i+j group of nozzles is above the object to be printed, control the i+j group of nozzles to spray ink onto the object to be printed.

[0100] S906: Determine if printing is complete. If yes, end the process; otherwise, update the values ​​of i and j and return to S902.

[0101] For example, by updating the values ​​of i and j above, the inkjet printing operations of S902 to S906 can be executed in a loop until i and j take all the values ​​of [1, n) in one loop. Then the printing can be determined to be completed, and the overall inkjet printing operation of the object to be printed is completed.

[0102] It should be understood that the specific implementation process of S901 to S906 can be referred to the method embodiments provided above. To avoid repetition, detailed descriptions are omitted here.

[0103] As can be seen from the above embodiments of this application, by adding a small amount of movement in the direction perpendicular to the length direction (i.e., the Y-axis direction) of the printhead and nozzle (i.e., the X-axis direction), the following technical effects can be achieved: printing curved objects with small vertical droplets, avoiding uneven ink droplet registration, improving inkjet effect, and ensuring printing efficiency; by setting the printhead nozzles and nozzles in parallel, the length of the printhead in the nozzle direction can be shortened, making the machine design space-saving and compact; expanding the application field, and meeting the customized needs of different customers.

[0104] Please refer to Figure 10 , Figure 10 The diagram illustrates a block diagram of an inkjet printing apparatus provided in some embodiments of this application. It should be understood that this inkjet printing apparatus corresponds to the method embodiments described above and is capable of performing the various steps involved in the method embodiments. The specific functions of this inkjet printing apparatus can be found in the description above; detailed descriptions are omitted here to avoid repetition.

[0105] Figure 10 The inkjet printing apparatus includes at least one software function module that can be stored in a memory or embedded in the inkjet printing apparatus in the form of software or firmware. The inkjet printing apparatus is applied to a printing device. The printhead base plate of the printing device has n sets of nozzles arranged side-by-side, including: a first control module 1010, used to control the central axis of the object to be printed to coincide with the center line of the i-th set of nozzles, where i is a positive integer, i∈[1, n), and n is a positive integer ≥2; and a second control module 1020, used to control the relative movement of the object to be printed and the i-th set of nozzles in a first direction, and when the i-th set of nozzles is above the object to be printed, controlling the i-th set of nozzles to eject ink onto the object to be printed. The first control module 1030 controls the object to be printed and the (i+j)th group of nozzles to move relative to each other in a second direction, so that the central axis of the object to be printed coincides with the center line of the (i+j)th group of nozzles, where i+j is a positive integer, i+j∈[1,n], j≠0; the second control module 1040 controls the object to be printed and the (i+j)th group of nozzles to move relative to each other in a first direction, and when the (i+j)th group of nozzles is above the object to be printed, controls the (i+j)th group of nozzles to spray ink onto the object to be printed, so as to complete the printing of the (i+j)th group of nozzles; wherein, the first direction is perpendicular to the second direction.

[0106] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the device described above can be referred to the corresponding process in the aforementioned method, and will not be elaborated further here.

[0107] Some embodiments of this application also provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, can perform the operation of any of the methods corresponding to the methods provided in the above embodiments.

[0108] Some embodiments of this application also provide a computer program product, which includes a computer program, wherein when the computer program is executed by a processor, it can implement the operation of any of the methods corresponding to the above embodiments provided in the above embodiments.

[0109] like Figure 11 As shown, some embodiments of this application provide an electronic device 1100, which includes a memory 1110, a processor 1120, and a computer program stored in the memory 1110 and executable on the processor 1120. When the processor 1120 reads the program from the memory 1110 via a bus 1130 and executes the program, it can implement the methods of any of the above embodiments.

[0110] Processor 1120 can process digital signals and may include various computing architectures. For example, it may be a complex instruction set computer architecture, a reduced instruction set computer architecture, or an architecture that implements multiple instruction set combinations. In some examples, processor 1120 may be a microprocessor.

[0111] Memory 1110 can be used to store instructions executed by processor 1120 or data related to the execution of instructions. These instructions and / or data may include code for implementing some or all of the functions of one or more modules described in the embodiments of this application. Processor 1120 of this disclosure embodiment can be used to execute instructions in memory 1110 to implement the methods shown above. Memory 1110 includes dynamic random access memory, static random access memory, flash memory, optical memory, or other memories well known to those skilled in the art.

[0112] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0113] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0114] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A method of inkjet printing, characterized by, The application is applied to a printing device, and a plurality of groups of nozzles are arranged side by side on a nozzle base plate of the printing device, wherein the groups of nozzles are determined by a selected printing mode. The groups of nozzles are selected from a plurality of groups of nozzles; and the method comprises the following steps: controlling a center axis of a to-be-printed object to coincide with a center line of an ith group of nozzles, wherein i is a positive integer, i ∈ [1, n), and n is a positive integer greater than or equal to 2; controlling relative movement of the to-be-printed object and the ith group of nozzles in a first direction, and controlling the ith group of nozzles to spray ink onto the to-be-printed object when the ith group of nozzles is located above the to-be-printed object, so as to complete printing of the ith group of nozzles; controlling relative movement of the to-be-printed object and an ith+jth group of nozzles in a second direction, so that the center axis of the to-be-printed object coincides with a center line of the ith+jth group of nozzles, wherein i+j is a positive integer, i+j ∈ [1, n], and j≠0; controlling relative movement of the to-be-printed object and the ith+jth group of nozzles in the first direction, and controlling the ith+jth group of nozzles to spray ink onto the to-be-printed object when the ith+jth group of nozzles is located above the to-be-printed object, so as to complete printing of the ith+jth group of nozzles; wherein the first direction is perpendicular to the second direction; and during printing, the to-be-printed object is controlled to continuously rotate around the center axis thereof.

2. The method of claim 1, wherein, Each of the ith group of nozzles and the ith+jth group of nozzles comprises a plurality of nozzle-containing sets, and each nozzle-containing set comprises a plurality of nozzle columns.

3. The method of claim 2, wherein, One physical nozzle comprises a plurality of nozzle columns.

4. The method of any one of claims 1-3, wherein, The diameter of the to-be-printed object is not greater than a set threshold.

5. The method of claim 2, wherein, Each group of nozzles of the ith group of nozzles belongs to an ith nozzle column, and each group of nozzles of the ith+jth group of nozzles belongs to an ith+jth nozzle column.

6. The method of claim 5, wherein, The nozzle base plate is provided with N nozzle columns arranged side by side, each nozzle column of the N nozzle columns is provided with a plurality of nozzles in the first direction; the n groups of nozzles are selected from the N nozzle columns, and N is a positive integer greater than 1.

7. The method of any one of claims 1-2, 5-6, wherein, The diameter of the to-be-printed object is greater than a set threshold.

8. The method of any one of claims 1-3, 5-6, wherein, The method further comprises the following steps: when the number of to-be-printed objects is M, the nozzle base plate is provided with M groups of nozzles, and each group of nozzles corresponds to one to-be-printed object, wherein M is greater than or equal to 2.

9. The method of any one of claims 1-3, 5-6, wherein: the to-be-printed object is a curved surface object of a cylinder or a cone.

10. An apparatus for inkjet printing, characterized by The application is applied to a printing device, and a plurality of groups of nozzles are arranged side by side on a nozzle base plate of the printing device, wherein the groups of nozzles are determined by a selected printing mode. The groups of nozzles are selected from a plurality of groups of nozzles; and the method comprises the following steps: a first control module is configured to control a center axis of a to-be-printed object to coincide with a center line of an ith group of nozzles, wherein i is a positive integer, i ∈ [1, n), and n is a positive integer greater than or equal to 2; a second control module configured to control relative movement of the object to be printed and the i-th group of nozzles in a first direction, and to control the i-th group of nozzles to spray ink onto the object to be printed when the i-th group of nozzles is above the object to be printed, so as to complete printing of the i-th group of nozzles; a third control module configured to control relative movement of the object to be printed and the i+j-th group of nozzles in a second direction, so that a central axis of the object to be printed coincides with a center line of the i+j-th group of nozzles, wherein i+j is a positive integer, i+j ∈ [1, n], and j≠0; a fourth control module configured to control relative movement of the object to be printed and the i+j-th group of nozzles in the first direction, and to control the i+j-th group of nozzles to spray ink onto the object to be printed when the i+j-th group of nozzles is above the object to be printed, so as to complete printing of the i+j-th group of nozzles; wherein the first direction is perpendicular to the second direction, and the object to be printed is controlled to continuously rotate around a central axis thereof during printing.

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