A multi-pass bi-directional jack shift inkjet printing method

Abstract

The present application relates to the field of inkjet printing, more particularly to a multi-PASS bidirectional jack shift inkjet printing method, wherein the printing method is that the inkjet assembly performs N times of scanning inkjet back and forth along the X-axis direction on the printing surface, wherein N >= 3, the inkjet assembly scans inkjet back and forth along the X-axis direction on the printing surface and shifts in the Y-axis direction; for solving the problem of improving the graphic printing resolution under the premise of ensuring the production efficiency and controlling the cost of the printer in the multi-PASS inkjet printing, so that under the premise of not increasing the number of PASS, only adjusting the shift direction and distance of different inkjet units along the Y-axis direction, the color difference caused by the fixed nozzle and different color superposition sequences can be reduced, the cost of installing multiple groups of nozzles is also reduced, the number of printing PASS is reduced under the same resolution, and the printing efficiency is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of inkjet printing, and more particularly, to a multi-PASS bidirectional jack displacement inkjet printing method. BACKGROUND

[0002] Traditional digital inkjet printing or digital inkjet printing can be divided into two categories according to the working mode: multi-PASS and single-PASS / one-PASS. Among them, the multi-PASS printing mode is that the substrate is fixed, and the image output is realized by moving the print head; the single-PASS printing mode is that the print head is fixed, and the image output is realized by moving the substrate. In the inkjet industry, the PASS value picture forming needs the number of times of printing, that is, the number of times of covering per unit area. The higher the PASS number, the slower the printing speed, and the better the printing quality. The PASS number is related to the printing accuracy. The advantage of multi-PASS scanning printing is that the errors that may occur in one scanning process of the print head can be covered by the next scanning. The more the scanning times, the more likely it is to cover the errors caused by single printing.

[0003] The prior art in the research direction of improving the printing effect resolution is to increase the PASS number or the number of print heads. The disadvantage of increasing the PASS number is that the printing speed is significantly reduced, which is not conducive to improving the production efficiency. The problem of increasing the number of print heads is that the cost of the printer is significantly increased, which is not conducive to the control of production cost. How to find a balance between the two and improve the printing effect resolution has become a technical problem in the field. SUMMARY

[0004] The present application aims to overcome at least one of the above-mentioned defects (shortcomings) of the prior art, and provides a multi-PASS bidirectional jack displacement inkjet printing method, which is used to solve the problem of improving the graphic printing resolution under the premise of ensuring production efficiency and controlling the cost of the printer in multi-PASS inkjet printing.

[0005] The technical scheme adopted by the present application is to provide a multi-PASS bidirectional jack displacement inkjet printing method, which comprises an inkjet assembly and a printing surface. The inkjet assembly moves ink above the printing surface. The printing surface has an X-axis direction along the scanning ink direction of the inkjet assembly and a Y-axis direction perpendicular to the scanning ink direction of the inkjet assembly. The inkjet assembly comprises a plurality of groups of print heads perpendicular to the X-axis. Each group of print heads prints the same color. Each group of print heads comprises a plurality of linearly arranged print heads. The spacing between two adjacent print heads in the same group of print heads in the Y-axis direction is L. Each print head comprises a plurality of columns of ink holes perpendicular to the X-axis. The spacing between two adjacent ink holes in the same column of ink holes in the Y-axis direction is Δ. The different groups of print heads of the plurality of print heads constituting the inkjet assembly at the same Y-axis coordinate constitute an inkjet unit. The spacing between two adjacent inkjet units in the Y-axis direction is L.

[0006] Wherein, the width of the printing surface in Y axis direction is H, the inkjet width of the inkjet assembly in Y axis direction is I, I-H≥L is satisfied, and the inkjet assembly is in the inkjet initial position, and the inkjet assembly exceeds not less than one inkjet unit in Y axis direction on the printing surface respectively; the printing method is that the inkjet assembly performs N times of scanning inkjet on the printing surface in X axis direction, wherein N≥3, and the specific process is as follows:

[0007] Step 1. The inkjet assembly is in the inkjet initial position in Y axis direction of the printing surface;

[0008] Step 2. The inkjet assembly performs scanning inkjet on the printing surface in X axis direction;

[0009] Step 3. It is judged whether the scanning inkjet times reaches N, if not, step 4 is performed, if yes, it is ended;

[0010] Step 4. The inkjet assembly is shifted relative to the printing surface in Y axis direction, and the shift distance P=n1*L+n2*Δ / N, wherein n1 or n2=1, 2, 3…;

[0011] Step 5. The inkjet assembly performs scanning inkjet on the printing surface in the opposite direction of X axis;

[0012] Step 6. It is judged whether the scanning inkjet times reaches N, if not, step 7 is performed, if yes, it is ended;

[0013] Step 7. The inkjet assembly is shifted relative to the printing surface in the opposite direction or the same direction of Y axis, and the shift distance P=n3L+n4Δ / N, wherein n3=2, 3, 4…, n4=1, 2, 3…, and when the inkjet assembly is shifted in the opposite direction of Y axis, n4≠n2;

[0014] The steps 2-7 are circularly performed until the scanning inkjet times reaches N, and it is ended.

[0015] It is beneficial to form the inkjet coverage area which is formed by the three groups of inkjet assemblies distributed in Y axis direction to exceed the width of the printing surface; it is beneficial to form multi-layer inkjet by combining the scanning inkjet of the inkjet assembly in X axis direction and the insertion inkjet in Y axis direction, so as to cover the obvious inkjet boundary line, and better printing inkjet effect is realized.

[0016] When the difference of I-H contains kL, k is 2, 3, 4…, when k+1≥N, in N times of scanning inkjet, the inkjet unit used at any position of the printing surface is not repeated, when k+1<N, in k+1 times of scanning inkjet, the inkjet unit used at any position of the printing surface is not repeated.

[0017] The ink jetting position on the printing surface is adjusted by multiple ink jetting units, and the ink jetting units used in every three scanning ink jetting are not repeated, so that the same printing surface is covered by at least three different ink jetting inks, and the ink jetting effect is improved; when the number of printing units is less than the number of scanning times, the printing units for ink jetting on the printing surface are not repeated, and when the number of printing units is greater than the number of scanning times, the printing units for ink jetting on the printing surface are not repeated and there are printing units without ink jetting at the same position.

[0018] When k is even, the number of ink jetting units exceeding the printing surface in the Y-axis direction is equal when the ink jetting assembly is in the initial ink jetting position; when k is odd, the number of ink jetting units exceeding the printing surface in the Y-axis direction is different by one when the ink jetting assembly is in the initial ink jetting position.

[0019] The ink jetting units are symmetrically distributed on the printing surface along the Y-axis direction, so that the distance of different ink jetting units moving to the same printing position is shortened, the adjustment time of the jack displacement is reduced, and the printing efficiency is effectively improved.

[0020] In step 7, the ink jetting assembly is displaced in the opposite direction of step 4 along the Y-axis, starting from the ink jetting unit close to the printing surface, and then alternately displacing upwards and downwards to the ink jetting unit far from the printing surface, and n1 and n2 are respectively odd sequences 1, 3, 5…, and even sequences 2, 4, 6…

[0021] The alternating ink jetting of the ink jetting units close to the printing surface to the ink jetting units far from the printing surface realizes the effect of bidirectional jack displacement, thereby avoiding the formation of obvious boundary lines by using ink jetting units with equal intervals; and by using different ink jetting units with different ink holes on the same printing surface, the printing precision is improved without increasing the number of scanning times.

[0022] When k=2, the ink jetting assembly is in the initial ink jetting position, and one ink jetting unit y1 and y2 respectively exceed the printing surface in the Y-axis direction, and the displacement sequence of steps 4 and 7 is y1y2 or y2y1.

[0023] The three ink jetting units on the printing surface are used to move the symmetrically distributed ink jetting units y1 and y2 to the ink jetting unit in the middle of the printing surface, so as to reduce the color difference formed by the fixed position ink jetting unit, and to improve the ink jetting precision.

[0024] When k=3, the inkjet assembly is in the initial position of inkjet, and one or two inkjet units y1, y2 and y3 are respectively overlapped above and below the printing surface along the Y-axis direction; when N is equal to 3, the displacement sequence of steps 4 and 7 is y1y2, y2y1, y1y3, y3y1, y2y3 or y3y2; when N≥4, the displacement sequence of steps 4 and 7 is y1y2y3, y3y2y1, y2y3y1, y1y3y2, y3y1y2 or y2y1y3.

[0025] Advantageously, by forming a specific displacement sequence through the inkjet units on the printing surface and the multiple inkjet units overlapped above and below the printing surface without increasing the number of inkjet printing PASS, not only the color difference formed by the fixed position inkjet units can be reduced, but also the overlapping sequence of the inkjet holes can be changed to change the inkjet effect.

[0026] When k=3, the inkjet assembly is in the initial position of inkjet, and two inkjet units y1, y2, y3 and y4 are respectively overlapped above and below the printing surface along the Y-axis direction; when N is equal to 3, the displacement sequence of steps 4 and 7 is one of the sequences of full permutation of any two inkjet units in y1-y4; when N is equal to 4, the displacement sequence of steps 4 and 7 is one of the sequences of full permutation of any three inkjet units in y1-y4; when N≥5, the displacement sequence of steps 4 and 7 is one of the sequences of full permutation of y1-y4.

[0027] Advantageously, by using a number of inkjet units greater than the number of PASS, redundant inkjet units are provided in each PASS printing inkjet, so as to reduce the use frequency of the inkjet units and achieve the effect of prolonging the service life of the inkjet units.

[0028] The resolution of single scanning inkjet of the inkjet assembly along the Y-axis is a, the target printing resolution of the printing method along the Y-axis is A, and N=a / A.

[0029] Advantageously, by multiple bidirectional plug-in inkjet of the inkjet assembly along the Y-axis direction, the number of times of covering ink on the same printing surface is increased, so as to achieve the effect of improving the resolution.

[0030] It also includes a printing inkjet space, a left buffer space and a right buffer space, the printing surface is located in the printing inkjet space, the left buffer space is located on the left side of the printing inkjet space, and the right buffer space is located on the right side of the printing inkjet space, the inkjet assembly moves uniformly along the X-axis direction in the printing inkjet space and moves at variable speed in the left buffer space and the right buffer space.

[0031] It is beneficial to ensure that the amount of ink contacted by each area of the printing surface is equal by the uniform-speed inkjet component in the printing and drawing space, to avoid the uneven thickness of the inkjet coverage layer; it is beneficial to stop and maintain, clean and overhaul the inkjet component in the operation space; and it is beneficial to observe and accurately adjust the insertion hole displacement distance of the inkjet component along the Y axis in the buffer space, so as to improve the printing effect.

[0032] Specifically, the following steps are included:

[0033] Step 01: the inkjet component is stopped at (x0, y0) in the left buffer space, step 1 is started, and after starting, it is moved to a position aligned with the initial position of the inkjet in the Y axis direction, reaching (x0, y1);

[0034] Step 02: the inkjet component starts step 2, enters the printing and drawing space, and reaches (x1, y1);

[0035] Step 03: the inkjet component starts step 3, uniformly sprays ink in the printing and drawing space, from (x1, y1) to (x2, y1);

[0036] Step 04: after the inkjet component completes the ink spraying, it enters the right buffer space and reaches (x3, y1);

[0037] Step 05: the inkjet component starts step 4, adjusts the step in the right buffer space to reach (x3, y2);

[0038] Step 06: the inkjet component starts step 5, returns to the printing and drawing space from the right buffer space, and reaches (x2, y2);

[0039] Step 07: the inkjet component follows the cycle of steps 2-7 to adjust the step in step 05 in the left buffer space and the right buffer space, and repeatedly uniformly sprays ink in step 03 in the printing and drawing space.

[0040] It is beneficial to start the inkjet printing task at any position on the printing surface by setting the inkjet initial position different from the stop position, and it is not necessary to calibrate the inkjet component to the stop position before starting each printing task; it is beneficial to shorten the start-stop time and the time of insertion hole displacement along the Y axis by the variable-speed inkjet component, so as to improve the printing efficiency.

[0041] Compared with the prior art, the beneficial effects of the present application are: by bidirectional insertion hole displacement inkjet in multiple PASS, the color difference caused by fixed nozzles and different color stacking sequences can be reduced by adjusting the displacement direction and distance of different inkjet units along the Y axis direction, the cost of installing multiple groups of nozzles is reduced, the number of PASS is reduced under the same resolution, and the printing efficiency is effectively improved. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the 4PASS printing effect of the three sets of printheads of the present invention.

[0043] Figure 2 This is a schematic diagram of the 4PASS printing effect of the four sets of printheads of the present invention.

[0044] Figure 3 This is a schematic diagram of the movement path of the inkjet assembly of the present invention. Detailed Implementation

[0045] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the invention. To better illustrate the following embodiments, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions; it is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0046] Example 1

[0047] like Figure 1 , 3 As shown, this embodiment is a 4PASS bidirectional socket shift printing method. The inkjet assembly has three groups of inkjet units, A, B, and C, arranged in a row-to-row configuration. The inkjet assemblies A, B, and C are arranged in a column-to-column KCMY four-color sequence. The oblong area is the printing surface, with inkjet unit B on the printing surface and inkjet units A and C extending beyond it. In this embodiment, the distance L between two adjacent printheads in the same group is 60mm along the Y-axis, and the distance Δ between two adjacent nozzles in the same column is 24mm along the Y-axis.

[0048] This embodiment is a 4PASS bidirectional jack printing method. After printing is completed using this method, the inkjet unit on the printing surface moves as a whole along the Y-axis by one jack spacing, i.e., Δ = 24mm.

[0049] After the inkjet assembly located in the operating space is started, the inkjet unit A moves downward along the Y-axis from the zero initial position to the inkjet initial position of the printing surface, and the insertion hole displacement distance P = L - Δ / N = 60 - 24 / 4 = 54 mm. In the first PASS, the ink covering the printing surface is ejected from the nozzle of the inkjet unit A, and the inkjet unit A moves along the X-axis from the zero initial position to the other end of the printing surface.

[0050] After the first PASS, the inkjet assembly is paused to the buffer space, and the nozzle displacement distance of inkjet unit A along the Y axis is adjusted; inkjet unit A is moved upward along the Y axis by a distance P = L + Δ / N = 60 + 24 / 4 = 66 mm; so that when the inkjet assembly starts the second PASS inkjet printing, the ink on the printing surface is ejected by the nozzle of inkjet unit B, inkjet unit B is moved to the zero initial position in the opposite direction of the first PASS along the X axis, and the nozzle positions of the first PASS and the second PASS at the same position on the printing surface differ by a nozzle displacement Δ / N = 24 / 4 = 6 mm along the Y axis.

[0051] After the second PASS, the inkjet assembly returns to the operation space, and the nozzle displacement distance of inkjet unit B along the Y axis is adjusted; inkjet unit B is moved upward along the Y axis by a distance P = L + Δ / N = 60 + 24 / 4 = 66 mm; so that when the inkjet assembly starts the third PASS inkjet printing, the ink on the printing surface is ejected by the nozzle of inkjet unit C, inkjet unit C is moved from the zero initial position to the other end of the printing surface along the X axis in the opposite direction of the second PASS, and the nozzle positions of the second PASS and the third PASS at the same position on the printing surface differ by a nozzle displacement Δ / N = 24 / 4 = 6 mm along the Y axis.

[0052] After the third PASS, the inkjet assembly is paused to the buffer space, and the nozzle displacement distance of inkjet unit C along the Y axis is adjusted; inkjet unit C is moved downward along the Y axis by a distance P = L - Δ / N = 60 - 24 / 4 = 54 mm; so that when the inkjet assembly starts the fourth PASS inkjet printing, the ink on the printing surface is ejected by the nozzle of inkjet unit B, inkjet unit B is moved to the zero initial position along the X axis in the opposite direction of the third PASS, and the nozzle positions of the third PASS and the fourth PASS at the same position on the printing surface differ by a nozzle displacement Δ / N = 24 / 4 = 6 mm along the Y axis.

[0053] In this embodiment, the moving speed of the inkjet assembly on the printing surface is not the same, when the inkjet assembly is parked in the operation space, the speed is 0, when the inkjet assembly is started, the inkjet assembly accelerates from 0 to v in the operation space, so that the inkjet assembly enters the printing and drawing space at a speed of v, in the printing and drawing space, the speed of the inkjet assembly remains at v, and the inkjet is uniformly ejected at a speed of v, after the end of the fourth PASS printing, the inkjet assembly returns to the operation space, and decelerates from v to 0 in the operation space, so that the inkjet assembly stops moving in the operation space, the user cleans, maintains and overhauls the inkjet assembly after the end of printing, to prolong the service life of the inkjet assembly.

[0054] Embodiment 2

[0055] like Figure 2 , 3 As shown, this embodiment is a 4PASS bidirectional socket shift printing method. The inkjet assembly has four inkjet units, A, B, C, and D, arranged in a row-to-row configuration. The inkjet assemblies A, B, C, and D are arranged in a column-to-column KCMY four-color sequence. The oblong area is the printing surface. Inkjet unit B is on the printing surface, while inkjet units A, C, and D extend beyond the printing surface, with inkjet unit A in front and inkjet units C and D behind. In this embodiment, the distance L between two adjacent printheads in the same printhead group in the Y-axis direction is 60mm, and the distance Δ between two adjacent nozzles in the same column in the Y-axis direction is 24mm.

[0056] This embodiment is a 4PASS bidirectional jack printing method. After printing is completed using this method, the inkjet unit on the printing surface moves as a whole along the Y-axis by two jack spacings, i.e., 2Δ = 48mm.

[0057] After the inkjet assembly located in the operating space is started, the inkjet unit B moves upward along the Y-axis from the zero initial position to the inkjet initial position of the printing surface, and the insertion hole displacement distance P = 2L - Δ / N = 120 - 24 / 4 = 114mm. In the first PASS, the ink covering the printing surface is ejected from the nozzle of the inkjet unit D, and the inkjet unit D moves along the X-axis from the zero initial position to the other end of the printing surface.

[0058] After the first pass, the inkjet assembly pauses in the buffer space and adjusts the insertion hole displacement distance of inkjet unit D along the Y-axis; the inkjet unit D is moved downward along the Y-axis by a distance P = 2L - 2Δ / N = 120 - 2*24 / 4 = 108mm; so that when the inkjet assembly starts printing the second pass, the ink covering the printing surface is ejected from the nozzle of inkjet unit B, and inkjet unit B moves to the zero initial position along the X-axis in the opposite direction to the first pass, and at the same position on the printing surface, the nozzle positions of the first pass and the second pass differ by a insertion hole displacement of 2Δ / N = 2*24 / 4 = 12mm along the Y-axis.

[0059] After the second pass, the inkjet assembly returns to the operating space and adjusts the insertion hole displacement distance of inkjet unit B along the Y-axis; the inkjet unit B is moved upward along the Y-axis by a distance P = L - 3Δ / N = 60 - 3 * 24 / 4 = 42 mm; so that when the inkjet assembly starts printing the third pass, the ink covering the printing surface is ejected from the nozzle of inkjet unit C, and inkjet unit C moves from the initial position at zero point to the other end of the printing surface along the X-axis in the opposite direction to the second pass, and at the same position on the printing surface, the nozzle positions of the second pass and the third pass differ by a insertion hole displacement of 2Δ / N = 2 * 24 / 4 = 12 mm along the Y-axis.

[0060] After the third PASS, the inkjet assembly is paused in the buffer space, and the insertion hole displacement distance of the inkjet unit C along the Y axis direction is adjusted, and the inkjet unit C is moved downward along the Y axis direction by a distance P = L - 4Δ / N = 120 - 4*24 / 4 = 96 mm; so that when the inkjet assembly starts the fourth PASS inkjet printing, the ink on the printing surface is ejected by the insertion hole of the inkjet unit A, the inkjet unit A is moved to the zero initial position in the direction opposite to the third PASS along the X axis, and the insertion hole positions of the third PASS and the fourth PASS on the same position of the printing surface are different by an insertion hole displacement 2Δ / N = 2*24 / 4 = 12 mm along the Y axis direction.

[0061] In the embodiment, the moving speed of the inkjet assembly on the printing surface is not the same, when the inkjet assembly is stopped in the operation space, the speed is 0, when the inkjet assembly is started, the inkjet assembly is accelerated from 0 to v in the operation space, so that the inkjet assembly enters the printing and drawing space at a speed of v, in the printing and drawing space, the speed of the inkjet assembly is kept at v, and the inkjet is uniformly sprayed at a speed of v, after the end of the fourth PASS printing, the inkjet assembly returns to the operation space, and is decelerated from v to 0 in the operation space, so that the inkjet assembly stops moving in the operation space, after the end of printing, the user cleans, maintains and overhauls the inkjet assembly to prolong the service life of the inkjet assembly.

[0062] Obviously, the above embodiments of the present application are only examples for clearly illustrating the technical solutions of the present application, and are not intended to limit the specific embodiments of the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A multi-PASS bidirectional slot shift inkjet printing method, comprising an inkjet assembly and a printing surface, the inkjet assembly moves inkjet above the printing surface, the printing surface has an X-axis direction along the inkjet assembly scanning inkjet direction and a Y-axis direction perpendicular to the inkjet assembly scanning inkjet direction; the inkjet assembly comprises a plurality of groups of inkjet head groups perpendicular to the X-axis, each group of inkjet head groups prints the same color, each group of inkjet head groups comprises a plurality of linearly arranged inkjet heads, the spacing between two adjacent inkjet heads in the same group of inkjet head groups in the Y-axis direction is L, and each inkjet head comprises a plurality of columns of inkjet orifices perpendicular to the X-axis, the spacing between two adjacent inkjet orifices in the same column in the Y-axis direction is Δ; a plurality of inkjet heads constituting the inkjet assembly constitute an inkjet unit at different groups of inkjet heads on the same Y-axis coordinate, and the spacing between two adjacent inkjet units in the Y-axis direction is L; characterized in that the width of the printing surface in the Y-axis direction is H, the inkjet width of the inkjet assembly in the Y-axis direction is I, I-H≥L is satisfied, and the inkjet assembly is respectively beyond not less than one inkjet unit above and below the printing surface in the Y-axis direction when in the inkjet initial position; the printing method is that the inkjet assembly performs N times of scanning inkjet back and forth along the X-axis direction on the printing surface, wherein N≥3, and the specific process is as follows: step 1. the inkjet assembly is in the inkjet initial position in the Y-axis direction of the printing surface; step 2. the inkjet assembly performs scanning inkjet on the printing surface along the X-axis direction; step 3. whether the number of scanning inkjet reaches N is judged, if not, step 4 is performed, and if yes, the process is ended; step 4. the inkjet assembly is shifted relative to the printing surface along the Y-axis direction, and the shift distance P=n1*L+n2*Δ / N, wherein n1 or n2=1, 2, 3…; step 5. the inkjet assembly performs scanning inkjet on the printing surface along the reverse direction of the X-axis; step 6. whether the number of scanning inkjet reaches N is judged, if not, step 7 is performed, and if yes, the process is ended; step 7. the inkjet assembly is shifted relative to the printing surface along the reverse direction or the same direction of the Y-axis, and the shift distance P=n3L+n4Δ / N, wherein n3=2, 3, 4…, n4=1, 2, 3…, and when the inkjet assembly is shifted along the reverse direction of the Y-axis, n4≠n2; the steps 2-7 are cycled until the number of scanning inkjet reaches N, and the process is ended. When the difference value of I-H contains kL, k is 2, 3, 4…, when k+1≥N, in N times of scanning inkjet, the inkjet unit used at any position of the printing surface is not repeated, and when k+1<N, in k+1 times of scanning inkjet, the inkjet unit used at any position of the printing surface is not repeated. When k is even, the number of inkjet units respectively beyond above and below the printing surface in the Y-axis direction when the inkjet assembly is in the inkjet initial position is equal; when k is odd, the number of inkjet units respectively beyond above and below the printing surface in the Y-axis direction when the inkjet assembly is in the inkjet initial position is different by one. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2. A multi-PASS bi-directional slot shift inkjet printing method according to claim 1, wherein, ​ 3. A multi-PASS bi-directional slot shift inkjet printing method according to claim 2, wherein, ​ 4. A multi-PASS bi-directional slot shift inkjet printing method according to claim 3, wherein, In step 7, the inkjet assembly is displaced along the Y axis in the opposite direction of step 4, starting from the inkjet unit close to the printing surface, and then alternately displacing upwards and downwards to the inkjet unit far from the printing surface, wherein n1 and n2 are respectively an odd sequence 1, 3, 5…, and an even sequence 2, 4, 6….

5. A multi-PASS bi-directional slot shift inkjet printing method according to claim 3, wherein, When k = 2, the inkjet assembly is in the initial inkjet position, and along the Y axis direction, it exceeds one inkjet unit y1 and y2 respectively above and below the printing surface, and the displacement sequence of step 4 and step 7 is y1y2 or y2y1.

6. A multi-PASS bi-directional slot shift inkjet printing method according to claim 3, wherein, When k = 3, the inkjet assembly is in the initial inkjet position, and along the Y axis direction, it exceeds one or two inkjet units y1, y2 and y3 respectively above and below the printing surface; when N is equal to 3, the displacement sequence of step 4 and step 7 is y1y2, y2y1, y1y3, y3y1, y2y3 or y3y2; when N ≥ 4, the displacement sequence of step 4 and step 7 is y1y2y3, y3y2y1, y2y3y1, y1y3y2, y3y1y2 or y2y1y3.

7. A multi-PASS bi-directional slot shift inkjet printing method according to claim 3, wherein, When k = 3, the inkjet assembly is in the initial inkjet position, and along the Y axis direction, it exceeds two inkjet units y1, y2, y3 and y4 respectively above and below the printing surface; when N is equal to 3, the displacement sequence of step 4 and step 7 is one of the sequences of full permutation of any two inkjet units in y1-y4; when N is equal to 4, the displacement sequence of step 4 and step 7 is one of the sequences of full permutation of any three inkjet units in y1-y4; when N ≥ 5, the displacement sequence of step 4 and step 7 is one of the sequences of full permutation of y1-y4.

8. A multi-PASS bi-directional slot shift inkjet printing method according to any of claims 1 to 7, characterized in that, The resolution of a single scan of the inkjet assembly along the Y axis is a, and the target printing resolution of the printing method along the Y axis is A, and N = a / A.

9. A multi-PASS bi-directional slot shift inkjet printing method according to any of claims 1 to 7, characterized in that, It also includes a printing and drawing space, a left buffer space and a right buffer space, the printing surface is located in the printing and drawing space, the left buffer space is located on the left side of the printing and drawing space, and the right buffer space is located on the right side of the printing and drawing space, the inkjet assembly moves uniformly along the X axis direction in the printing and drawing space, and moves at variable speed in the left buffer space and the right buffer space.

Images