A jack shift inkjet printing method

Abstract

The present application relates to inkjet printing technology field, provide a jack shift inkjet printing method, inkjet vehicle includes multiple groups of nozzles, realize different color ink drawing, each group of nozzles includes multiple in Y direction on the arrangement, same color nozzle, nozzle is arranged into multiple rows in X direction, A nozzle and B nozzle are any two rows, the distance of A nozzle and B nozzle in Y direction is L, each nozzle includes multiple orifices, the distance of orifice in Y is delta, with a position on the printing platform as initial position, to solve the problem of improving graphic printing resolution in the premise of guaranteeing production efficiency and controlling printer cost in multiple PASS inkjet printing, the influence of color difference brought by different nozzles in printing process is reduced, the resolution of printing effect is improved by multiple coverage inkjet, the cost of using multiple groups of nozzles is reduced, the number of multiple PASS printing is reduced, and printing efficiency is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of inkjet printing technology, and more particularly, to a jack shift 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 printing times, that is, the number of coverings 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 the improvement of 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 jack shift inkjet printing method 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 a jack shift inkjet printing method. The inkjet vehicle includes multiple groups of print heads to realize different color ink drawing. Each group of print heads includes multiple print heads of the same color arranged in the Y direction. The print heads are arranged in multiple rows in the X direction. A and B print heads are any two rows. The distance between the A print head and the B print head in the Y direction is L. Each print head includes multiple nozzles. The distance between the nozzles in the Y direction is Δ. A position on the printing platform is taken as the initial position. The method specifically includes the following steps:

[0006] Step 1: the inkjet vehicle starts from the initial position;

[0007] Step 2: the inkjet vehicle completes the first scanning inkjet along the X axis direction;

[0008] Step 3, the inkjet vehicle realizes the position exchange of the A nozzle and the B nozzle by a displacement distance P in the Y axis direction, the displacement distance P=L±Δ / n or P=(L±Δ) / n, wherein n is the PASS number;

[0009] Step 4, the inkjet vehicle completes the next scanning inkjet in the X axis direction opposite to the last scanning inkjet;

[0010] Step 5, if the scanning inkjet number is less than n, the inkjet vehicle repeats the step 3 and the step 4; if the scanning inkjet number is equal to the PASS number, the printing is completed.

[0011] Further, the A nozzle and the B nozzle are arranged adjacently. It is beneficial to eliminate the color difference of different nozzles on the printing medium by the nozzle displacement, and to improve the printing precision and effect.

[0012] Further, the 2PASS jack displacement inkjet printing specifically includes the following steps:

[0013] Step 1, the inkjet vehicle starts from an initial position;

[0014] Step 2, the inkjet vehicle completes the first scanning inkjet in the X axis direction;

[0015] Step 3, the inkjet vehicle realizes the position exchange of the A nozzle and the B nozzle by a displacement distance P in the Y axis direction, the displacement distance P=L±Δ / 2 or P=(L±Δ) / 2;

[0016] Step 4, the inkjet vehicle completes the second scanning inkjet in the X axis direction opposite to the first scanning inkjet;

[0017] Step 5, the printing is completed.

[0018] Further, the inkjet vehicle has an inkjet width I on the Y axis which is at least one L more than the width H of the printing medium. It is beneficial to the nozzle to cover the edge position of the printing medium in the printing process, and to increase the inkjet coverage of the scanning printer.

[0019] Further, n is an even number. It is beneficial to the inkjet vehicle to return to the same initial position after each printing, which is convenient for the correction of the next printing of the inkjet vehicle and the maintenance of the inkjet vehicle.

[0020] Further, the C nozzle is a row different from the A nozzle or the B nozzle, and the step 3 realizes the position exchange of any two rows of the A nozzle, the B nozzle and the C nozzle by a displacement distance P in the Y axis direction. It is beneficial to realize different jack displacement distances by increasing the nozzle group to form multi-layer coverage inkjet, and to further eliminate the color difference.

[0021] Further, in the 2PASS hole displacement inkjet printing process, the nozzle position exchange order of the A nozzle, the B nozzle and the C nozzle in the step 3 is A-B or A-C or B-C. It is beneficial to realize the printing of two layers of ink on the printing medium by the displacement printing between any two groups of nozzles in the three groups of nozzles in the 2PASS inkjet printing process, so as to achieve the effect of eliminating color difference.

[0022] Further, each group of nozzles comprises two columns of nozzles E and F which are staggered in the Y direction, and the two nozzles E and F have an overlapping area, the nozzles in the overlapping area are at the same position in the Y direction, in each inkjet process, the opening number of the nozzles of the E nozzle in the overlapping area accounts for a%, the opening number of the nozzles of the F nozzle in the overlapping area accounts for b%, a%+b%=100%, and the values of a or b are randomly changed in different inkjet processes. It is beneficial to prevent a clear color difference line from being printed on the printing medium, because the positions of the adjacent two nozzles are fixed, and there is a slight color difference between the ink jetted by the different nozzles, so when the nozzles jet ink, the use of the fixed position nozzles for inkjet will easily form a color difference line, and the random selection of nozzles for inkjet can effectively avoid the generation of color difference line.

[0023] Further, a random number is calculated, a is given, and b=100-a. It is beneficial to ensure that the selection of nozzles is random and cannot be predicted, so as to avoid regular color difference lines on the printing medium.

[0024] Further, the random number is taken from the color of any position of any image, and is converted into the random number of a. It is beneficial to prevent the computer generated random number from being not a true random number, and to bring a better printing effect by generating a random number from the color of the existing picture.

[0025] Compared with the prior art, the beneficial effects of the present application are: by the method of A, B adjacent nozzles alternating inkjet and nozzle multiple nozzle hole inkjet, the color difference caused by different nozzles in the printing process is reduced, the resolution of the printing effect is improved by multiple coverage inkjet, the cost of using multiple groups of nozzles is reduced, the number of multiple PASS printing is reduced, and the printing efficiency is effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a preferred embodiment of the present application, which is a schematic diagram of the effect of the first PASS to the second PASS in the 2PASS printing of the nozzle arranged by column.

[0027] Figure 2 is a preferred embodiment of the present application, which is a schematic diagram of the effect of the first PASS to the second PASS in the 2PASS printing of the staggered nozzle.

[0028] Figure 3 is a schematic diagram of the effect of the first pass to the second pass in 3PASS printing by the column-arranged nozzles of a preferred embodiment of the present application.

[0029] Figure 4 is a schematic diagram of the effect of the second pass to the third pass in 3PASS printing by the column-arranged nozzles of a preferred embodiment of the present application.

[0030] Figure 5 is a schematic diagram of the effect of the first pass to the second pass in 3PASS printing by the staggered-arranged nozzles of a preferred embodiment of the present application.

[0031] Figure 6 is a schematic diagram of the effect of the second pass to the third pass in 3PASS printing by the staggered-arranged nozzles of a preferred embodiment of the present application.

[0032] Figure 7 is a schematic diagram of the effect of the first pass to the second pass in 4PASS printing by the column-arranged nozzles of a preferred embodiment of the present application.

[0033] Figure 8 is a schematic diagram of the effect of the second pass to the third pass in 4PASS printing by the column-arranged nozzles of a preferred embodiment of the present application.

[0034] Figure 9 is a schematic diagram of the effect of the third pass to the fourth pass in 4PASS printing by the column-arranged nozzles of a preferred embodiment of the present application.

[0035] Figure 10 is a schematic diagram of the effect of the fourth pass to the end-of-printing rest position in 4PASS printing by the column-arranged nozzles of a preferred embodiment of the present application.

[0036] The figure identification explanation: nozzle spacing L, nozzle hole spacing Δ, PASS number n, displacement distance P of the inkjet carriage, printing medium width H, nozzle inkjet width I, nozzle hole inkjet width I1. DETAILED DESCRIPTION

[0037] The drawings of the present application are only for illustrative purposes and should not be understood as limiting the present application. In order to better illustrate the following embodiments, some components of the drawings may be omitted, enlarged or reduced, and do not represent the actual product size; it is understandable to those skilled in the art that some well-known components and their descriptions in the drawings may be omitted.

[0038] Example 1

[0039] As Figure 1As shown, the embodiment is a 2PASS scanning printing method, the inkjet vehicle is provided with A and B two groups of nozzles, A and B two groups of nozzles are arranged in front and back by column, the long circular dotted line is the inkjet range of the nozzle, Figure 1 The nozzle on the right side of the printing medium is the position where the inkjet vehicle stops when starting the first PASS, Figure 1 The nozzle on the left side of the printing medium is the position where the inkjet vehicle stops when starting the second PASS in the Y axis direction with a displacement distance P. The installation distance of the two groups of nozzles is L, L = 120 mm in the embodiment, the A group of nozzles is provided with three nozzles, which are A1, A2 and A3 respectively, the B group of nozzles is also provided with three nozzles, which are B1, B2 and B3 respectively, the nozzle distance of the two groups of nozzles is Δ, Δ = 40 mm in the embodiment, the interposition distance in the 2PASS interposition printing process is 1 / 2 of the nozzle distance, the interposition distance is Δ / 2 = 20 mm in the embodiment, A1 at the starting position is the reference line of the inkjet vehicle, and the displacement distance P of the inkjet vehicle in each PASS is the displacement distance of A1. As Figure 1 As shown, the dotted area is a schematic diagram of the printing effect of the nozzles of A and B groups in China, the inkjet width of the nozzle is I1, the inkjet width of the nozzle is I, and the width of the printing medium is H.

[0040] When the inkjet vehicle is at the starting position, it stops on the right side of the printing medium, the nozzles above the printing medium are A1, A2 and A3; when the inkjet vehicle starts the first PASS in the 2PASS, the inkjet vehicle moves uniformly along the X axis direction from the right side of the printing platform to the left side of the printing platform, the nozzles A1, A2 and A3 in the nozzle A above the printing medium are synchronously inkjet, the nozzles in the nozzle B do not inkjet, after the inkjet vehicle moves to the left side of the printing medium, the printing medium is covered with the first layer of ink drops; when the inkjet vehicle starts the second PASS in the 2PASS, the inkjet vehicle stops at the left side of the printing platform, at this time, the inkjet vehicle moves uniformly along the Y axis direction from below to above, moves the nozzle B to the position where the nozzle A stops originally, and moves upward by an interposition distance, that is, the displacement distance P of the inkjet vehicle in the Y axis direction is L + Δ / 2 = 120 mm + 20 mm = 140 mm, the inkjet vehicle moves uniformly along the X axis direction from the left side of the printing platform to the right side of the printing platform, the nozzles B2 and B3 in the nozzle B above the printing medium are synchronously inkjet, the nozzles in the nozzle A do not inkjet, after the inkjet vehicle moves to the right side of the printing medium, the printing medium is covered with the second layer of ink drops; after the two layers of ink drops are superimposed, the inkjet vehicle returns to the starting position in the Y axis direction, thus, a complete 2PASS printing process is completed.

[0041] The resolution of the printed image and text is doubled compared to the single PASS printing because the 2PASS printing uses two groups of adjacent nozzles to print. The two-layer ink droplet coverage can reduce the color difference between the two groups of nozzles. In order to avoid the obvious color difference caused by the fixed nozzle in the two groups of nozzles, the nozzles in the 2PASS printing process use a random switching method to print. In this embodiment, the nozzles A1, A2, and A3 in each PASS do not refer to the fixed three nozzles in nozzle A, but refer to any three nozzles in nozzle A. The same applies to nozzle B. The selection of random nozzles uses a random number control to control the opening and closing ratio of the nozzles in the two groups of nozzles A and B. The random number can be set in multiple ways. The implementer can select a true random number or a false random number according to the needs on site. Alternatively, an arbitrary color block can be selected from the existing image and text, enlarged, and compared with the standard color card to obtain a random number.

[0042] Embodiment 2

[0043] As shown in Figure 2 , this embodiment is a 2PASS scanning printing method. The inkjet vehicle is provided with two groups of nozzles A and B. The two groups of nozzles A and B are arranged in a staggered manner. The long circular dashed line represents the inkjet range of the nozzles, Figure 2 , the right side of the printing medium is the position where the inkjet vehicle stops when starting the first PASS, Figure 2 , the left side of the printing medium is the position where the inkjet vehicle stops after generating a displacement distance P in the Y-axis direction when starting the second PASS. The installation distance between the two groups of nozzles is L. In this embodiment, L = 100 mm. The nozzle A is provided with three nozzles, namely A1, A2, and A3. The nozzle B is also provided with three nozzles, namely B1, B2, and B3. The distance between the nozzles of the two groups of nozzles is Δ. In this embodiment, Δ = 40 mm. The distance between the nozzles in the 2PASS printing process is 1 / 2 of the distance between the nozzles. In this embodiment, the distance between the nozzles is Δ / 2 = 20 mm. The A1 at the starting position is the reference line of the inkjet vehicle. The displacement distance P of the inkjet vehicle in each PASS is the displacement distance of A1. Figure 1 , the dashed area is a schematic diagram of the printing effect of the nozzles in the two groups of nozzles A and B. The inkjet width of the nozzles is I1. The inkjet width of the nozzles is I. The width of the printing medium is H.

[0044] When the inkjet vehicle is at the starting position, it stays at the right side of the printing medium, and the nozzles A1, A2, A3 above the printing medium are used for inkjet; when the inkjet vehicle starts the first PASS in the 2PASS, the inkjet vehicle moves at a constant speed along the X axis direction from the right side of the printing platform to the left side of the printing platform, the nozzles A1, A2, A3 in the inkjet head A above the printing medium are used for inkjet synchronously, and the nozzles in the inkjet head B are not used for inkjet; after the inkjet vehicle moves to the left side of the printing medium, the printing medium is covered with the first layer of ink drops; when the inkjet vehicle starts the second PASS in the 2PASS, the inkjet vehicle stays at the left side of the printing platform, at this time, the inkjet vehicle moves at a constant speed along the Y axis direction from below to above, moves the inkjet head B to the position where the inkjet head A stays in the previous step, and moves further upward by one jack spacing, that is, the displacement distance P of the inkjet vehicle in the Y axis direction is L+Δ / 2=100 mm+20 mm=120 mm, the inkjet vehicle moves at a constant speed along the X axis direction from the left side of the printing platform to the right side of the printing platform, the nozzles B2, B3 in the inkjet head B above the printing medium are used for inkjet synchronously, and the nozzles in the inkjet head A are not used for inkjet; after the inkjet vehicle moves to the right side of the printing medium, the printing medium is covered with the second layer of ink drops; after the superposition of the two layers of ink drops is completed, the inkjet vehicle returns to the starting position in the Y axis direction, and thus the complete 2PASS printing process is completed.

[0045] Since the graphics and texts printed by the 2PASS are printed by the adjacent nozzles A and B respectively, the resolution of the graphics and texts is improved by 2 times compared with the graphics and texts printed by the single PASS. The coverage of the two layers of ink drops can reduce the color difference of the nozzles A and B, in order to avoid the obvious color difference stripes caused by the fixed nozzles in the two groups of nozzles, the nozzles in the 2PASS printing process are used for inkjet in a random switching mode, in the embodiment, the nozzles A1, A2, A3 used for inkjet in each PASS do not refer to the fixed three nozzles in the inkjet head A, but refer to any three nozzles in the inkjet head A, and the inkjet head B is the same, the selection of the random nozzles uses a random number control, the random number control is used to control the switching proportion of the nozzles in the inkjet heads A and B, and the random number has multiple setting modes, the implementer can select a true random number or a false random number according to the site needs, or can select any color block from the existing graphics and texts, enlarge the color block, and compare the color in the enlarged color block with a standard color card to obtain a random number.

[0046] Embodiment 3

[0047] As shown in Figure 3 , 4 , the embodiment is a 3PASS scanning printing method, the inkjet vehicle is provided with two groups of inkjet heads A and B, the two groups of inkjet heads A and B are arranged in front and back by column, the long circular dashed line is the inkjet range of the nozzles, Figure 3 , the inkjet head on the right side of the printing medium is the position where the inkjet vehicle stays when starting the first PASS, Figure 3The position where the ink jet carriage stops when the left side printhead of the middle printing medium generates a displacement distance P in the Y axis direction at the beginning of the second PASS, Figure 4 The position where the ink jet carriage stops when the left side printhead of the middle printing medium generates a displacement distance P in the Y axis direction at the beginning of the second PASS, Figure 4 The position where the ink jet carriage stops when the right side printhead of the middle printing medium generates a displacement distance P in the Y axis direction at the beginning of the third PASS. The installation distance between the two groups of printheads is L, L = 90 mm in this embodiment. The printhead of group A is provided with three nozzles, A1, A2 and A3, and the printhead of group B is also provided with three nozzles, B1, B2 and B3. The distance between the nozzles of the two groups of printheads is Δ, Δ = 30 mm in this embodiment. The distance between the insertion holes in the 3 PASS insertion hole printing process is 1 / 3 of the distance between the nozzles, the insertion hole distance is Δ / 3 = 10 mm in this embodiment. The nozzle A1 at the starting position is the reference line of the ink jet carriage, and the displacement distance P of the ink jet carriage in each PASS is the displacement distance of A1. As shown in Figure 1 The dashed area is the printing effect diagram of the nozzles of the two groups of printheads, the ink jet width of the nozzles is I1, the ink jet width of the printheads is I, and the width of the printing medium is H.

[0048] When the inkjet vehicle is at the starting position, it stays at the right side of the printing medium, and the nozzles A1, A2 and A3 above the printing medium are used for inkjet; when the inkjet vehicle starts the first PASS in the 3PASS, the inkjet vehicle moves at a constant speed along the X axis from the right side of the printing platform to the left side of the printing platform, the nozzles A1, A2 and A3 in the inkjet head A above the printing medium are used for inkjet, and the nozzles in the inkjet head B are not used for inkjet; after the inkjet vehicle moves to the left side of the printing medium, the first layer of ink droplets is covered on the printing medium; when the inkjet vehicle starts the second PASS in the 2PASS, the inkjet vehicle stays at the left side of the printing platform, at this time, the inkjet vehicle moves at a constant speed along the Y axis from the bottom to the top, moves the inkjet head B to the position where the inkjet head A stays in the last step, and moves upward by one insertion hole pitch, i.e. the displacement distance P of the inkjet vehicle in the Y axis direction is L+Δ / 3=90mm+10mm=100mm, then the inkjet vehicle moves at a constant speed along the X axis from the left side of the printing platform to the right side of the printing platform, the nozzles B2 and B3 in the inkjet head B above the printing medium are used for inkjet, and the nozzles in the inkjet head A are not used for inkjet; after the inkjet vehicle moves to the right side of the printing medium, the second layer of ink droplets is covered on the printing medium; when the inkjet vehicle starts the third PASS in the 3PASS, the inkjet vehicle stays at the right side of the printing platform, at this time, the inkjet vehicle moves at a constant speed along the Y axis from the top to the bottom, moves the inkjet head A to the position where the inkjet head B stays in the last step, and moves upward by one insertion hole pitch, i.e. the displacement distance P of the inkjet vehicle in the Y axis direction is L-Δ / 3=90mm-10mm=80mm, then the inkjet vehicle moves at a constant speed along the X axis from the right side of the printing platform to the left side of the printing platform, the nozzles A1, A2 and A3 in the inkjet head A above the printing medium are used for inkjet, and the nozzles in the inkjet head B are not used for inkjet; after the inkjet vehicle moves to the left side of the printing medium, the third layer of ink droplets is covered on the printing medium; after the three layers of ink droplets are superimposed, the inkjet vehicle is adjusted to the starting position in the Y axis direction, and thus the complete 3PASS printing process is completed.

[0049] Since the graphics and texts printed by the 3PASS are printed by the adjacent inkjet heads A and B using the nozzles, the resolution of the graphics and texts is improved by 3 times compared with the graphics and texts printed by the single PASS. The coverage of the three layers of ink droplets can reduce the color difference of the inkjet heads A and B. In order to avoid the obvious color difference stripes caused by the inkjet using the fixed nozzles in the two inkjet heads, the inkjet is performed by randomly opening and closing the nozzles in the 3PASS printing process, in the embodiment, the nozzles A1, A2 and A3 in each PASS do not refer to the fixed three nozzles in the inkjet head A, but refer to any three nozzles in the inkjet head A, and the inkjet head B is the same. The selection of the random nozzles is controlled by a random number, and the opening and closing ratio of the nozzles in the inkjet heads A and B is controlled by the random number. The random number can be set in many ways, and the implementer can select the true random number or the false random number according to the site needs, or can select any color block from the existing graphics and texts, enlarge the color block, and compare the color in the enlarged color block with the standard color card to obtain a random number.

[0050] Example 4

[0051] As shown in Figure 5 , 6 , this embodiment is a 3PASS scanning printing method, the inkjet vehicle is provided with A and B two groups of nozzles, the A and B two groups of nozzles are arranged in staggered rows and columns, the long circular dotted line is the inkjet range of the nozzle hole, Figure 5 , the right side nozzle of the printing medium is the position where the inkjet vehicle stops when starting the first PASS, Figure 5 , the left side nozzle of the printing medium is the position where the inkjet vehicle stops after generating a displacement distance P in the Y axis direction when starting the second PASS, Figure 6 , the left side nozzle of the printing medium is the position where the inkjet vehicle stops when ending the second PASS, Figure 6 , the right side nozzle of the printing medium is the position where the inkjet vehicle stops when starting the third PASS after generating a displacement distance P in the Y axis direction. The installation distance of the two groups of nozzles is L, in this embodiment, L = 80 mm, the A group of nozzles is provided with three nozzle holes, which are A1, A2 and A3, the B group of nozzles is also provided with three nozzle holes, which are B1, B2 and B3, the nozzle hole distance of the two groups of nozzles is Δ, in this embodiment, Δ = 30 mm, the jack distance in the 3PASS jack printing process is 1 / 3 of the nozzle hole distance, in this embodiment, the jack distance is Δ / 3 = 10 mm, taking A1 of the starting position as the reference line of the inkjet vehicle, the displacement distance P of the inkjet vehicle in each PASS is the displacement distance of A1. As shown in Figure 1As shown, the dashed area is a schematic diagram of the printing effect of the nozzles of the two groups of printheads, the ink ejection width of the nozzles is I1, the ink ejection width of the printhead is I, and the width of the printing medium is H. When the inkjet vehicle is at the starting position, it stays on the right side of the printing medium, and the nozzles above the printing medium are A1, A2, and A3. When the inkjet vehicle starts the first PASS in the 3PASS, the inkjet vehicle moves at a constant speed along the X-axis direction from the right side of the printing platform to the left side of the printing platform, the nozzles A1, A2, and A3 in the printhead A above the printing medium synchronously eject ink, the nozzles in the printhead B do not eject ink, and after the inkjet vehicle moves to the left side of the printing medium, the printing medium is covered with the first layer of ink droplets. When the inkjet vehicle starts the second PASS in the 2PASS, the inkjet vehicle stays on the left side of the printing platform, at this time, the inkjet vehicle moves at a constant speed along the Y-axis direction from bottom to top, moves the printhead B to the position where the printhead A stays in the previous step, and moves upward by one insertion hole pitch, that is, the displacement distance P of the inkjet vehicle in the Y-axis direction is L+Δ / 3=80 mm+10 mm=90 mm, the inkjet vehicle moves at a constant speed along the X-axis direction from the left side of the printing platform to the right side of the printing platform, the nozzles B2 and B3 in the printhead B above the printing medium synchronously eject ink, the nozzles in the printhead A do not eject ink, and after the inkjet vehicle moves to the right side of the printing medium, the printing medium is covered with the second layer of ink droplets. When the inkjet vehicle starts the third PASS in the 3PASS, the inkjet vehicle stays on the right side of the printing platform, at this time, the inkjet vehicle moves at a constant speed along the Y-axis direction from top to bottom, moves the printhead A to the position where the printhead B stays in the previous step, and moves upward by one insertion hole pitch, that is, the displacement distance P of the inkjet vehicle in the Y-axis direction is L-Δ / 3=80 mm-10 mm=70 mm, the inkjet vehicle moves at a constant speed along the X-axis direction from the right side of the printing platform to the left side, the nozzles A1, A2, and A3 in the printhead A above the printing medium synchronously eject ink, the nozzles in the printhead B do not eject ink, and after the inkjet vehicle moves to the left side of the printing medium, the printing medium is covered with the third layer of ink droplets. After the three layers of ink droplets are superimposed, the inkjet vehicle is adjusted back to the starting position in the Y-axis direction, and thus, a complete 3PASS printing process is completed.

[0052] Since the 3PASS printing uses A and B two groups of adjacent nozzles to print, the resolution of the printed image is 3 times higher than that of the single PASS printing. The three-layer ink droplet coverage can reduce the color difference between A and B two groups of nozzles. In order to avoid the obvious color difference caused by the fixed nozzle of the two groups of nozzles, the nozzle uses a random switching mode to print in the 3PASS printing process. In this embodiment, the nozzles A1, A2 and A3 in each PASS refer to any three nozzles in the nozzle A, and the nozzle B is the same. The selection of the random number controls the opening and closing ratio of the nozzles in A and B two groups of nozzles. There are many ways to set the random number, and the implementer can select the true random number or the false random number according to the needs on the spot. The implementer can also select any color block from the existing image and enlarge it, and then compare the color in the enlarged color block with the standard color card to obtain a random number.

[0053] Embodiment 5

[0054] As shown in Figures 7-10 , this embodiment is a 4PASS scanning printing method, and the inkjet vehicle is provided with A and B two groups of nozzles. A and B two groups of nozzles are arranged in front and back according to rows and columns. The long circular dotted line is the inkjet range, Figure 4 , the right side nozzles of the printing medium are the positions where the inkjet vehicle stops when starting the first PASS to the second PASS and the positions where the inkjet vehicle stops after the Y-axis direction displacement distance P when ending the second PASS, Figure 5 , the left side nozzles of the printing medium are the positions where the inkjet vehicle stops when starting the second PASS to the third PASS and the positions where the inkjet vehicle stops after the Y-axis direction displacement distance P when ending the third PASS, Figure 6 , the right side nozzles of the printing medium are the positions where the inkjet vehicle stops when starting the third PASS to the fourth PASS and the positions where the inkjet vehicle stops after the Y-axis direction displacement distance P when ending the fourth PASS. The installation distance between the two groups of nozzles is L, and L=100mm in this embodiment. The A group of nozzles is provided with three nozzles, which are A1, A2 and A3. The B group of nozzles is also provided with three nozzles, which are B1, B2 and B3. The nozzle spacing of the two groups of nozzles is Δ, and Δ=20mm in this embodiment. The nozzle spacing in the 4PASS printing process is 1 / 4 of the sum of the nozzle spacing and the nozzle spacing. In this embodiment, the nozzle spacing is (L+Δ) / 4=(100mm+20mm) / 4=30mm. Taking A1 of the starting position as the reference line of the inkjet vehicle, the displacement distance P of the inkjet vehicle in each PASS is the displacement distance of A1. As shown in Figure 1 , the dotted area is a schematic diagram of the printing effect of the nozzles of A and B two groups of nozzles. The inkjet width of the nozzle is I1, the inkjet width of the nozzle is I, and the width of the printing medium is H.

[0055] When the inkjet vehicle is at the starting position, it stays at the right side of the printing medium, and the nozzles A1, A2, A3 above the printing medium are used for inkjet; when the inkjet vehicle starts the first PASS in the 4PASS, it moves at a constant speed along the X axis from the right side of the printing platform to the left side of the printing platform, the nozzles A1, A2, A3 in the inkjet head A above the printing medium are used for inkjet, the nozzles in the inkjet head B are not used for inkjet, the inkjet vehicle moves at a constant speed along the Y axis from the bottom to the top by one pitch, that is, the displacement distance P of the inkjet vehicle in the Y axis direction is (L+Δ) / 4=(100mm+20mm) / 4=30mm, after the inkjet vehicle moves to the left side of the printing medium, the first layer of ink droplets is covered on the printing medium; when the inkjet vehicle starts the second PASS in the 4PASS, it moves at a constant speed along the X axis from the left side of the printing platform to the right side of the printing platform, the nozzles B1, B2, B3 in the inkjet head B above the printing medium are used for inkjet, the nozzles in the inkjet head A are not used for inkjet, the inkjet vehicle moves at a constant speed along the Y axis from the bottom to the top by one pitch, that is, the displacement distance P of the inkjet vehicle in the Y axis direction is (L+Δ) / 4=(100mm+20mm) / 4=30mm, after the inkjet vehicle moves to the right side of the printing medium, the second layer of ink droplets is covered on the printing medium; when the inkjet vehicle starts the third PASS in the 4PASS, it moves at a constant speed along the X axis from the right side of the printing platform to the left side of the printing platform, the nozzles A1, A2, A3 in the inkjet head A above the printing medium are used for inkjet, the nozzles in the inkjet head B are not used for inkjet, the inkjet vehicle moves at a constant speed along the Y axis from the bottom to the top by one pitch, that is, the displacement distance P of the inkjet vehicle in the Y axis direction is (L+Δ) / 4=(100mm+20mm) / 4=30mm, after the inkjet vehicle moves to the left side of the printing medium, the third layer of ink droplets is covered on the printing medium; when the inkjet vehicle starts the fourth PASS in the 4PASS, it moves at a constant speed along the X axis from the left side of the printing platform to the right side of the printing platform, the nozzles B2, B3 in the inkjet head B above the printing medium are used for inkjet, the nozzles in the inkjet head A are not used for inkjet, the inkjet vehicle moves at a constant speed along the Y axis from the bottom to the top by one pitch, that is, the displacement distance P of the inkjet vehicle in the Y axis direction is (L+Δ) / 4=(100mm+20mm) / 4=30mm, after the inkjet vehicle moves to the right side of the printing medium, the fourth layer of ink droplets is covered on the printing medium; after the four layers of ink droplets are superimposed, a complete 4PASS printing process is finished, after the printing process is finished, the inkjet head B moves to the starting position of the inkjet head A by one nozzle pitch Δ=20mm, and the relative displacement distance of the inkjet head B relative to the printing width H is L+Δ=100mm+20mm=120mm.

[0056] Since the graphic and text printed by 4PASS uses A and B two groups of adjacent nozzles to print, the resolution of the graphic and text is increased by 4 times compared with the graphic and text printed by single PASS. The coverage of four layers of ink drops can reduce the color difference of the nozzles of A and B two groups. In order to avoid the obvious color difference strip caused by the fixed nozzle of the ink jet of the nozzles in the two groups, the nozzles in the 4PASS printing process use the random switching mode to jet ink. In the embodiment, the nozzles A1, A2 and A3 in each PASS do not refer to the fixed three nozzles of the nozzle A, but refer to any three nozzles of the nozzle A. The nozzle B is the same. The selection of the random nozzles uses random number control. The random number is used to control the opening and closing ratio of the nozzles of A and B two groups. There are many ways to set the random number. The implementer can select true random number or false random number according to the needs on the spot. The implementer can also select any color block from the existing graphic and text, enlarge the color block, compare the color in the enlarged color block with the standard color card, and obtain a random number.

[0057] Embodiment 6

[0058] In the embodiment, the distance L between the nozzle A and the nozzle B changes according to the type of the selected nozzle. When the nozzle is selected as the Toshiba CF3 type, the distance L is 53.49 mm, and the single switching number is 12. When the nozzle is selected as the Seiko RC1536 type, the distance L is 107.24 mm. When the nozzle is selected as the Seiko RCE2560 type, the distance L is 108.01 mm, and the single switching hole number is 8. When the nozzle is selected as the Jingqian KJ4B-QA type, the distance L is 108.04 mm, and the single switching hole number is 6. When the nozzle is selected as the Sail XAAR type, the distance L is 70 mm.

[0059] Obviously, the above embodiments of the present application are only examples for clearly illustrating the technical scheme 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 socket-shifting inkjet printing method, wherein the inkjet carriage includes multiple sets of printheads to achieve different color printing, each set of printheads includes multiple printheads of the same color arranged in the Y direction, the printheads are arranged in multiple rows in the X direction, printhead A and printhead B are any two rows, the distance between printhead A and printhead B in the Y direction is L, each printhead includes multiple nozzles, the distance between the nozzles in the Y direction is Δ, and the method is based on a position on the printing platform as the initial position, specifically including the following steps: Step 1: The inkjet carriage starts from the initial position; Step 2: The inkjet carriage completes the first scanning inkjet print along the X-axis. Step 3: The inkjet carriage moves along the Y-axis by a displacement distance P to swap the positions of printhead A and printhead B. The displacement distance P = L ± Δ / n or P = (L ± Δ) / n, ​​where n is the number of passes. Step 4: The inkjet carriage completes the next scanning inkjet in the opposite direction of the X-axis of the previous scanning inkjet. Step 5: If the number of scan-type inkjet prints is less than n, the inkjet carriage repeats steps 3 and 4; if the number of scan-type inkjet prints is equal to n, printing ends. Printhead C is a row that is different from printhead A or printhead B. In step 3, the inkjet carriage moves along the Y-axis by a displacement distance P to interchange the positions of any two rows of printheads A, B, and C.

2. The jack-shifting inkjet printing method according to claim 1, wherein Nozzle A and nozzle B are installed adjacent to each other.

3. The jack shifting inkjet printing method according to claim 1, specifically includes the following steps: Step 1: The inkjet carriage starts from the initial position; Step 2: The inkjet carriage completes the first scanning inkjet print along the X-axis. Step 3: The inkjet carriage moves along the Y-axis by a displacement distance P to swap the positions of printhead A and printhead B. The displacement distance P = L ± Δ / 2 or P = (L ± Δ) / 2. Step 4: The inkjet carriage completes the second scanning inkjet process in the opposite direction of the X-axis; Step 5, printing complete.

4. The jack-shifting inkjet printing method of claim 1, wherein The inkjet carriage's inkjet width I on the Y-axis is at least one L greater than the width H of the printing medium.

5. The jack-shifting inkjet printing method of claim 1, wherein n is an even number.

6. The jack-shifting inkjet printing method of claim 1, wherein During the 2PASS socket shift inkjet printing process, the printhead positions of printheads A, B, and C are interchanged in step 3 in the order of AB, AC, or BC.

7. A jack-shifting inkjet printing method according to any one of claims 1 to 6, characterized in that, Each printhead group includes two rows of E printheads and F printheads staggered in the Y direction. There is an overlap area between the E printheads and F printheads. The nozzles in the overlap area are in the same position in the Y direction. During each inkjet process, the percentage of the number of nozzles opened by the E printheads in the overlap area is a%, and the percentage of the number of nozzles opened by the F printheads in the overlap area is b%. a% + b% = 100%. The value of a or b changes randomly in different inkjet processes.

8. The jack-shifting inkjet printing method of claim 7, wherein, Calculate a random number and assign it to a, then b = 100 - a.

9. The jack-shifting inkjet printing method of claim 8, wherein, The random number is taken from the color at any position in any image and converted into a random number assigned to 'a'.

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