A multi-pass inkjet printer

Abstract

The present application relates to the field of large-format inkjet printing, more particularly, to a multi-PASS inkjet printer, which is arranged above the printing platform, comprising two sub-frames distributed along the X direction, a suspension beam connected below the sub-frames, and a cleaning and maintenance assembly, the sub-frames and the suspension beam form a buffer space, a printing inkjet space and an operation space, the cleaning and maintenance assembly is arranged in the operation space, the suspension beam comprises one, the inkjet vehicle comprises multiple groups of nozzles to realize different color inkjet, and specifically comprises five steps. To solve the problems of too long printing time when improving the printing resolution, insufficient stability of the support structure, and large space occupied by the maintenance components, complex installation, short service life of the inkjet printer, and high use cost. Improve the printing effect and the degree of precise control; realize the stability of the reinforcing frame, simple and portable production and installation; increase the bending strength of the suspension beam; improve the use efficiency of the nozzle, prolong the service life of the nozzle, and improve the utilization rate of the overall space of the printer.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of large-format inkjet printing, and more particularly, to a multi-PASS inkjet printer. 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 to print the number of 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 during one scan of the print head can be covered by the next scan. The more the number of scans, the more likely it is to cover the errors caused by single printing.

[0003] The prior art increases the number of PASS or the number of print heads to improve the printing accuracy. Increasing the number of PASS reduces the printing speed, which is not conducive to improving the production efficiency. Increasing the number of print heads significantly increases the cost of the printer, which is not conducive to controlling the production cost.

[0004] How to solve the problems of long printing time, low efficiency, high printing cost, and insufficient resolution of printed images and texts of the multi-PASS inkjet printer, and the problem of large wear of the support structure caused by uneven force distribution during repeated scanning and moving of the inkjet vehicle. In addition, the support structure not only needs to solve the problem of structural stability, but also needs to provide a sufficient space for the inkjet vehicle and an easy-to-install space. How to improve the service life of the inkjet printer by maintaining the print head, and how to avoid the installation complexity and large space occupation of the maintenance components are technical problems that need to be solved in the field. SUMMARY

[0005] The present application aims to overcome at least one of the above-mentioned defects (shortcomings) of the prior art, and provides a multi-PASS inkjet printer to solve the problem of improving the resolution of multi-PASS inkjet printing while the printing time is too long, which is not conducive to the printing efficiency. The support structure provided for the inkjet vehicle is not stable enough and is not easy to install. The maintenance components provided for the inkjet vehicle occupy a large space and are complex to install, which makes it impossible to solve the problems of short service life and high use cost of the inkjet printer.

[0006] The technical scheme adopted by the present application is a multi-PASS inkjet printer arranged above a printing platform, wherein two sub-frames distributed along an X direction are arranged, a suspension beam connected below the sub-frames is arranged, and a cleaning and maintenance assembly is arranged in an operation space formed by the sub-frames and the suspension beam. The suspension beam comprises one suspension beam, the suspension beam supports an inkjet vehicle to slide thereon through a suspension structure, the inkjet vehicle comprises multiple groups of inkjet heads to realize different color inkjet, each group of inkjet heads comprises multiple inkjet heads of the same color arranged in a Y direction, the inkjet heads are arranged in multiple rows in an X direction, A inkjet heads and B inkjet heads are any two rows, the distance between the A inkjet heads and the B inkjet heads in the Y direction is L, each inkjet head comprises multiple inkjet nozzles, the distance between the inkjet nozzles in the Y direction is Δ, and one position on the printing platform is taken as an initial position, and the method comprises the following steps:

[0007] Step 1: the inkjet vehicle starts from the initial position;

[0008] Step 2: the inkjet vehicle completes the first scanning inkjet along the X axis direction;

[0009] Step 3: the inkjet vehicle realizes the exchange of positions of the A inkjet heads and the B inkjet heads by a displacement distance P along the Y axis direction, the displacement distance P is L±Δ / n or (L±Δ) / n, wherein n is the number of PASS;

[0010] Step 4: the inkjet vehicle completes the next scanning inkjet along the reverse direction of the X axis of the last scanning inkjet;

[0011] Step 5: if the number of scanning inkjet is less than n, the inkjet vehicle repeats steps 3 and 4; if the number of scanning inkjet is equal to n, the printing is completed.

[0012] The multi-PASS inkjet printing method is beneficial to improve the printing effect of the pattern, eliminate the color difference of the pattern, and increase the resolution; the sub-frames are beneficial to provide more stable support force for the suspension beam, so that the overall structure of the printer is more stable when the multi-PASS reciprocating printing is performed, and the shaking of the inkjet vehicle is avoided to affect the accuracy; the suspension beam and the suspension structure are beneficial to limit the sliding track of the inkjet vehicle and drive the sliding direction of the inkjet vehicle, so as to accurately control the displacement of the inkjet vehicle; and the cleaning and maintenance assembly is beneficial to clean, moisturize, and replace the moisturizing assembly of the inkjet heads in the inkjet vehicle, so as to strengthen the inkjet printing effect of the inkjet heads and prolong the service life of the inkjet vehicle.

[0013] Further, the A inkjet heads and the B inkjet heads are arranged adjacently.

[0014] The two groups of inkjet heads arranged adjacently are beneficial to inkjet at the same time when the inkjet vehicle is displaced, so that the color difference caused by the height of the inkjet heads, the voltage of the inkjet heads, and the temperature difference of the inkjet on the printing medium is covered, thereby improving the printing accuracy and the printing effect.

[0015] Further, the C nozzle is different from the A nozzle or the B nozzle, and the step 3 is to exchange the positions of any two rows of the A nozzle, the B nozzle and the C nozzle by a displacement distance P along the Y axis direction.

[0016] It is beneficial to alternate ink jetting by multiple groups of nozzles when the ink jetting vehicle is displaced, so that the color difference coverage range of the multiple groups of nozzles is further expanded compared to the color difference coverage range of adjacent groups of nozzles, thereby avoiding the obvious color difference boundary line generated after two groups of nozzles are fixed for color difference coverage, and further improving the printing effect.

[0017] Further, the ink jetting width I of the ink jetting vehicle on the Y axis is at least one L more than the width H of the printing medium.

[0018] It is beneficial to enable the nozzles to cover the edge and corner positions of the printing medium during printing, thereby increasing the ink jetting coverage of the scanning printer.

[0019] Further, the suspension beam is a rectangular beam structure, the rectangular beam is composed of at least two rectangular sub-beams with the same length, the rectangular sub-beam is a hollow beam, and the inside is provided with a transverse support and a longitudinal support, and the width of the rectangular sub-beam is not greater than the height.

[0020] It is beneficial to strengthen the strength of the rectangular beam by splicing two rectangular sub-beams, simplify the installation of the rectangular beam structure, manufacture the rectangular beam by using the existing hollow beam, thereby reducing the manufacturing cost of the suspension beam, and guide and distribute the stress on the rectangular sub-beam to the entire rectangular beam structure through the transverse support and the longitudinal support penetrating through the entire hollow beam, thereby avoiding excessive stress concentration and affecting the service life of the rectangular beam.

[0021] Further, the suspension structure includes a driving device, the driving device is a linear motor in the X axis and Y axis connection direction of the ink jetting vehicle, and the driving device is a lead screw in the Z axis connection direction of the ink jetting vehicle.

[0022] It is beneficial to drive the movement of the ink jetting vehicle in the X axis and Y axis directions by the linear motor, and it is beneficial to improve the precision of the displacement control of the ink jetting vehicle in the height direction by the lead screw, thereby realizing the jack displacement multi-PASS scanning printing effect of the ink jetting vehicle on the printing medium, and it is beneficial to simplify the control components of the ink jetting vehicle by the lead screw, thereby simplifying the maintenance process and reducing the maintenance cost.

[0023] Further, the cleaning and maintenance assembly includes an ink receiving groove, and the ink receiving groove is arranged in the buffer space and used for waste ink collection of the ink jetting vehicle.

[0024] The waste ink after cleaning the ink jet head can be collected and guided through the ink receiving groove, thereby prolonging the service life of the ink jet vehicle; the ink receiving groove arranged in the buffer space saves space for the printer, thereby reducing the overall volume of the printer; and the ink jet head at both ends of the ink jet vehicle can be conveniently cleaned and maintained by the operator.

[0025] Further, the cleaning and maintenance assembly further comprises a cleaning assembly arranged in the operation space for cleaning the ink jet head on the ink jet vehicle.

[0026] The ink jet head with ink droplets adhered can be washed and wiped by the cleaning assembly, thereby avoiding the solidification of ink droplets on the ink jet head to affect the ink jet effect of the ink jet head, further improving the use efficiency of the ink jet head and prolonging the service life of the ink jet head.

[0027] Further, the cleaning and maintenance assembly further comprises a moisturizing assembly arranged in the operation space for isolating and moisturizing the ink jet head on the ink jet vehicle.

[0028] The ink jet head after cleaning can be moisturized and sealed by the moisturizing assembly, thereby avoiding the ink droplets in the ink jet head from being affected by the external environment to re-solidify, so that the ink jet head can smoothly jet ink in the next use, thereby improving the use efficiency of the ink jet head and prolonging the service life of the ink jet head.

[0029] Further, the cleaning and maintenance assembly further comprises a moisturizing film conveying assembly arranged in the operation space for replacing the moisturizing assembly.

[0030] The moisturizing assembly can be replaced by the moisturizing film conveying assembly at regular intervals, so that the humidity in the moisturizing assembly is maintained within a higher numerical range, further improving the use efficiency of the ink jet head and prolonging the service life of the ink jet head.

[0031] Compared with the prior art, the beneficial effects of the present application are: the frame provides support for the ink jet vehicle that reciprocally scans and jets ink; the sub-frame enhances the stability of the frame and provides a wider moving space for the ink jet vehicle, and the frame is simpler and more portable to manufacture and install; the rectangular sub-beam increases the bending strength of the suspended beam; the suspended structure drives the ink jet vehicle to realize multi-PASS jack displacement printing effect in X and Y axis directions, and precise height control in Z axis direction; the cleaning and maintenance assembly realizes the collection and drainage of waste ink, the cleaning and moisturizing of the ink jet head, improves the use efficiency of the ink jet head, prolongs the service life of the ink jet head, and improves the utilization rate of the overall space of the printer. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a front view of the multi-PASS ink jet printer of the present application.

[0033] Figure 2 A perspective view of the multi-PASS inkjet printer of the present application.

[0034] Figure 3 An end view of the cantilever structure of the present application.

[0035] Figure 4 An enlarged view of the cleaning and maintenance assembly of the present application.

[0036] Figure 5 An enlarged view of the ink receiving groove of the present application.

[0037] Figure 6 An enlarged view of the cleaning assembly of the present application.

[0038] Figure 7 An enlarged view of the moisturizing assembly and the moisturizing film conveying assembly of the present application.

[0039] Figure 8 An enlarged view of the 2PASS hole displacement printing effect of the present application.

[0040] Figure legend: buffer space 10, printing space 20, operation space 30, sub-frame 100, cantilever 200, rectangular sub-beam 210, transverse support 211, longitudinal support 212, intermediate support plate 213, inkjet vehicle 300, cleaning and maintenance assembly 400, ink receiving groove 410, cleaning assembly 420, moisturizing assembly 430, moisturizing film conveying assembly 440, nozzle spacing L, hole spacing Δ, PASS number n, displacement distance of inkjet vehicle P, printing medium width H, nozzle inkjet width I, hole inkjet width I1. DETAILED DESCRIPTION

[0041] The drawings of the present application are only for illustrative purposes and should not be construed 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 size of the product; it is understandable for those skilled in the art that some well-known structures and their descriptions in the drawings may be omitted.

[0042] Example 1

[0043] As Figures 1-7As shown, the embodiment provides a multi-PASS inkjet printer, which is arranged above a printing platform, wherein two sub-frames 100 are distributed along the X direction, a suspension beam 200 is connected below the sub-frames 100, and a cleaning and maintenance assembly 400 is arranged in the operation space 30 formed by the sub-frames 100 and the suspension beam 200. The suspension beam 200 includes one, and supports an inkjet vehicle 300 to slide thereon through a suspension structure. The inkjet vehicle 300 includes multiple groups of inkjet heads to realize different color printing, each group of inkjet heads includes multiple inkjet heads of the same color arranged in the Y direction, and the inkjet heads are arranged in multiple rows in the X direction. A and B are any two rows of inkjet heads, the distance between A and B in the Y direction is L, each inkjet head includes multiple inkjet nozzles, the distance between the inkjet nozzles in the Y direction is Δ, and one position on the printing platform is taken as an initial position. The embodiment specifically includes the following steps:

[0044] Step 1: the inkjet vehicle 300 starts from the initial position;

[0045] Step 2: the inkjet vehicle 300 completes the first scanning inkjet along the X axis;

[0046] Step 3: the inkjet vehicle 300 realizes the position exchange between A and B inkjet heads by shifting the distance P along the Y axis, the shift distance P = L ± Δ / n or P = (L ± Δ) / n, wherein n is the number of PASS;

[0047] Step 4: the inkjet vehicle 300 completes the next scanning inkjet along the reverse direction of the X axis of the last scanning inkjet;

[0048] Step 5: if the number of scanning inkjet is less than n, the inkjet vehicle 300 repeats steps 3 and 4; if the number of scanning inkjet is equal to n, the printing is completed.

[0049] In this embodiment, before starting the inkjet printing work, the printing file is first converted into the format required by the printing control software through the image raster image processor. After loading, the operator clicks print in the operation space 30. After the printer reads the loaded printing file information, the printing task is started. The inkjet vehicle 300 slides along the track of the suspension beam 200 to the printing and plotting space 20 from the operation space 30. The inkjet vehicle 300 moves on the printing and plotting space 20 and performs the first scan inkjet along the track of the suspension beam 200. After inkjetting, the inkjet vehicle 300 continues to slide along the track of the suspension beam 200 to the buffer space 10, so that the inkjet vehicle 300 is temporarily stopped in the buffer space 10. At the same time, the inkjet vehicle 300 starts to adjust the displacement in the Y direction, so that the inkjet range is shifted in the Y direction by a distance P = L ± Δ / 2 or P = (L ± Δ) / 2. After adjusting the displacement distance, the inkjet vehicle 300 slides from the buffer space 30 to the printing and plotting space 20. At this time, the inkjet vehicle 300 returns along the track of the suspension beam 200 to perform the second scan inkjet. After completing the inkjet, the inkjet vehicle 300 stops in the operation space 30.

[0050] When the inkjet vehicle 300 is temporarily stopped in the buffer space 10, the waste ink on the inkjet vehicle 300 is concentrated and drained into the ink receiving groove 410. The waste ink in the ink receiving groove 410 is connected to the waste ink bottle to achieve the effect of concentrated treatment of waste ink. When the inkjet vehicle 300 is stopped in the operation space 30 after completing the inkjet printing work, the nozzles on the inkjet vehicle 300 are cleaned by the cleaning assembly 420, and then the cleaned nozzles are moisturized by the moisturizing assembly 430 to prevent the nozzles from being affected by the external environment to cause the condensation of ink droplets again. Until the next time the inkjet vehicle 300 is started for inkjet printing, the nozzles on the inkjet vehicle 300 will always be kept in a sealed and closed moisturizing state by the moisturizing assembly 430. When the inkjet vehicle 300 is ready to start printing, the moisturizing assembly 430 is separated from the nozzles. Until the next time the moisturizing assembly 430 isolates and closes the nozzles, the moisturizing assembly 430 is replaced by the moisturizing film conveying assembly 440, and the nozzles can maintain the best moisturizing state every time they are isolated and closed by the replaced moisturizing assembly 430.

[0051] A nozzle is arranged adjacent to a B nozzle.

[0052] In the embodiment, the 2PASS inkjet printing includes two times of inkjet, and the first inkjet and the second inkjet have the same range of travel and opposite directions. After the adjacent A nozzle and B nozzle are colored by the first inkjet, the inkjet vehicle 300 adjusts the jack displacement in the Y direction, and the adjacent A nozzle and B nozzle are simultaneously inkjetted and colored by the second inkjet, so that the color difference of the first coloration can be covered by the second coloration, thereby improving the printing precision and printing effect.

[0053] The C nozzle is a row different from the A nozzle or the B nozzle. The step 3 inkjet vehicle 300 exchanges the positions of any two rows of the A nozzle, the B nozzle and the C nozzle by the displacement distance P in the Y axis direction.

[0054] In the embodiment, the 2PASS inkjet printing includes two times of inkjet, and the first inkjet and the second inkjet have the same range of travel and opposite directions. After the adjacent A nozzle and B nozzle are colored by the first inkjet, the inkjet vehicle 300 adjusts the jack displacement in the Y direction, and the adjacent A nozzle and B nozzle are simultaneously inkjetted and colored by the second inkjet, so that the color difference of the first coloration can be covered by the second coloration, thereby improving the printing precision and printing effect.

[0055] The inkjet width I of the inkjet vehicle in the Y axis is at least one L more than the width H of the printing medium.

[0056] In the embodiment, the inkjet width I of the inkjet vehicle in the Y axis is one L more than the width H of the printing medium. The width I can also be one integer times L more than the width H.

[0057] The suspension beam is a rectangular beam structure, the rectangular beam is composed of at least two rectangular sub-beams with the same length, the rectangular sub-beam is a hollow beam, and the inside is provided with a transverse support and a longitudinal support, and the width of the rectangular sub-beam is not greater than the height.

[0058] In the embodiment, the suspension beam 200 is a rectangular beam structure, which is used to offset the bending wear caused by the reciprocating movement of the inkjet vehicle 300, so as to improve the bending strength of the suspension beam 200; the rectangular beam is welded by two rectangular sub-beams 210 with the same length, width and height; in order to avoid that the rectangular sub-beam 210 is too heavy to cause the stress strength of the frame to be too large, thereby affecting the service life of the frame, the rectangular sub-beam 210 is a hollow beam; in order to further improve the bending strength of the rectangular sub-beam 210, 9 transverse supports 211 and 9 longitudinal supports 212 are arranged in the rectangular sub-beam 210, and the transverse supports 211 are simultaneously connected to the two rectangular sub-beams 210.

[0059] The suspension structure comprises a driving device, the driving device is a linear motor in the connection direction of the X axis and the Y axis of the inkjet vehicle, and the driving device is a lead screw in the connection direction of the Z axis of the inkjet vehicle.

[0060] In the embodiment, the linear motor drives the inkjet vehicle 300 to move in the X direction and the Y direction, controls the start, stop, speed change and travel direction of the inkjet vehicle 300 in the X direction, and controls the displacement distance of the inkjet vehicle 300 in the Y direction; the lead screw drives the inkjet vehicle 300 to adjust the inkjet height along the Z axis direction; the operator sets the parameters of the linear motor and the lead screw through the control panel before starting the inkjet vehicle 300 to spray ink, and can also adjust the parameters of the linear motor and the lead screw through the control panel when stopping the inkjet vehicle 300 to spray ink.

[0061] The cleaning and maintenance assembly 400 comprises an ink receiving groove 410 arranged in the buffer space 10, which is used for waste ink collection of the inkjet vehicle 300.

[0062] In the embodiment, the inkjet vehicle 300 generates a large amount of waste ink during the inkjet printing process due to the plurality of inkjet heads installed on the inkjet vehicle 300, and the inkjet vehicle 300 needs to be maintained and cleaned in time by the operator. When the inkjet vehicle 300 travels to the buffer space 10, the operator cleans the inkjet heads at one end of the inkjet vehicle 300 away from the operation space 30 to prevent the operator from not cleaning the inkjet vehicle 300 thoroughly in the operation space 30. At this time, the ink receiving groove 410 can collect waste ink and waste water generated during the cleaning process. In addition, the inkjet vehicle 300 can have the phenomenon of ink droplets falling from the inkjet heads. The ink receiving groove 410 can also collect the ink droplets. The ink receiving groove 410 is arranged in the buffer space 10, adjacent to and flush with the printing platform. The ink receiving groove 410 is in the shape of a funnel, which can not only make the ink receiving surface of the waste ink large enough to increase the collection capacity, but also make the waste ink flow slowly along the slope to control the flow rate of the waste ink, waste water, and ink droplets in the ink receiving groove 410.

[0063] The cleaning and maintenance assembly 400 further comprises a cleaning assembly 420 arranged in the operation space 30 for cleaning the inkjet heads on the inkjet vehicle 300.

[0064] In the embodiment, the inkjet heads on the inkjet vehicle 300 are prone to ink condensation and clogging after a long time of printing. To solve the above problem, the cleaning assembly 420 is used to clean the inkjet heads. When the inkjet vehicle 300 completes printing and is parked in the operation space 30, the cleaning assembly 420 arranged in the operation space 30 moves to the lower side of the inkjet vehicle 300. The cleaning assembly 420 moves back and forth along the Y direction and cleans the inkjet heads by negative pressure adsorption to keep the inkjet heads clean.

[0065] The cleaning and maintenance assembly 400 further comprises a moisturizing assembly 430 arranged in the operation space 30 for isolating and moisturizing the inkjet heads on the inkjet vehicle 300.

[0066] The cleaning and maintenance assembly 400 further comprises a moisturizing film conveying assembly 440 arranged in the operation space 30 for replacing the moisturizing assembly 430.

[0067] In this embodiment, when the inkjet carriage 300 starts, the printhead disengages from the moisturizing component 430, allowing the inkjet carriage 300 to move from the operating space 30 to the printing space 20. When the inkjet carriage 300 completes printing and stops in the operating space 30, the cleaning component cleans the printhead. After cleaning, the cleaning component 420 retracts outside the inkjet carriage 300, and the moisturizing component 430 moisturizes the cleaned printhead. The moisturizing component 430 is a moisturizing film that seals and moisturizes all the printheads on the inkjet carriage 300 to isolate the humidity of the printheads from the external environment. When the inkjet carriage 300 completes the next printing and stops in the operating space 30, the printheads cleaned by the cleaning component 420 need to be moisturized again. At this time, the moisturizing film conveying component 440 conveys a new moisturizing film to the printheads via a roller structure, completely sealing the printheads for moisture isolation.

[0068] In this embodiment, the moisturizing component 430 is disposed above the moisturizing film conveying component 440. The moisturizing component 430 moves up and down in the Z-axis direction to achieve contact or separation between the printhead and the moisturizing component 430. The highest horizontal plane of the moisturizing film conveying component 440 is lower than the horizontal plane of the printing platform to avoid contact with the printhead during the replacement of the moisturizing film.

[0069] Example 2

[0070] like Figure 8 As shown, the inkjet carriage 300 in this embodiment is a schematic diagram of the 2-pass socket shift printing effect. The inkjet carriage 300 is equipped with two sets of printheads, A and B, which are arranged in a column front and back. The oblong dotted line represents the inkjet range of the nozzle. Figure 5 As shown, the printhead on the right side of the printing medium is the position where the inkjet carriage 300 stops when it starts its first pass, and the printhead on the left side of the printing medium is the position where the inkjet carriage 300 stops after a displacement distance P in the Y-axis direction when it starts its second pass. The installation distance between the two sets of printheads is L, which is 120mm in this embodiment. The A set of printheads has 3 nozzles, namely A1, A2, and A3, and the B set of printheads also has 3 nozzles, namely B1, B2, and B3. The nozzle spacing on both sets of printheads is Δ, which is 40mm in this embodiment. The spacing between the 2-pass insertion holes during printing is 1 / 2 of the nozzle spacing, which is Δ / 2 = 20mm in this embodiment. Taking the starting position A1 as the baseline of the inkjet carriage, the displacement distance P of the inkjet carriage for each pass is the displacement distance of A1. Figure 5 As shown, the dashed area is a schematic diagram of the printing effect of the nozzles of two sets of printheads A and B. The ink jet width of the nozzle is I1, the ink jet width of the printhead is I, and the width of the printing medium is H.

[0071] When the inkjet vehicle 300 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 300 starts the first PASS in the 2PASS, the inkjet vehicle 300 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 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 300 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 300 starts the second PASS in the 2PASS, the inkjet vehicle 300 stays at the left side of the printing platform, at this time, the inkjet vehicle 300 moves at a constant speed along the Y axis direction from the bottom to the top, moves the inkjet head B to the position where the inkjet head A stays, and then moves upward by one insertion hole pitch, that is, the displacement distance P of the inkjet vehicle 300 in the Y axis direction is L+Δ / 2=120mm+20mm=140mm, then the inkjet vehicle 300 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 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 300 moves to the right side of the printing medium, the second layer of ink droplets is covered on the printing medium; after the two layers of ink droplets are superimposed, the inkjet vehicle 300 returns to the starting position in the Y axis direction, and thus the complete 2PASS printing process is finished.

[0072] Since the A and B two groups of adjacent inkjet heads are used for printing by insertion hole respectively in the 2PASS printing, the resolution of the figure and text is improved by 2 times compared with the figure and text printed by the single PASS. The coverage of the two layers of ink droplets can reduce the color difference of the A and B two groups of inkjet heads, in order to avoid the obvious color difference strip caused by the fixed nozzles in the two groups of inkjet heads, the nozzles in the 2PASS printing process are used for inkjet in the random opening and closing mode, in the embodiment, the nozzles A1, A2 and A3 in each PASS for inkjet 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 adopts the random number control, the random number is used for controlling the opening and closing proportion of the nozzles in the A and B two groups of inkjet heads, and the random number has multiple setting modes, 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 figure and text, enlarges the color block, compares the color in the enlarged color block with the standard color card, and obtains a random number.

[0073] 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 implementation manner 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 inkjet printer, disposed above a print platform, characterized in that, The application relates to a printing device, which comprises two sub-frames distributed along an X direction, a suspension beam connected to the lower part of the sub-frames, and a cleaning and maintaining assembly arranged in an operating space formed by the sub-frames and the suspension beam, wherein the suspension beam comprises one suspension beam structure, the suspension beam structure is a rectangular beam structure, the rectangular beam structure is formed by splicing at least two rectangular sub-beams with the same length, the rectangular sub-beams are hollow beams, the interior of the rectangular sub-beams is provided with transverse supports and longitudinal supports, the width of the rectangular sub-beams is not greater than the height, the suspension beam supports an ink jet vehicle to slide thereon through a suspension structure, the ink jet vehicle comprises a plurality of groups of ink jets, different color printing is realized, each group of ink jets comprises a plurality of ink jets with the same color arranged in a Y direction, the ink jets are arranged in multiple rows in an X direction, A ink jets and B ink jets are any two rows, the distance between the A ink jets and the B ink jets in the Y direction is L, each ink jet comprises a plurality of ink holes, the distance between the ink holes in the Y direction is Delta, and one position on a printing platform is taken as an initial position. Step 1: the ink jet vehicle starts from the initial position; Step 2: the ink jet vehicle completes the first scanning ink jet along the X axis direction; Step 3: the ink jet vehicle realizes the position exchange of the A ink jets and the B ink jets by a displacement distance P along the Y axis direction, the displacement distance P is L+ / -Delta / n, wherein n is the number of PASS; Step 4: the ink jet vehicle completes the next scanning ink jet in the running range of the last scanning ink jet along the direction opposite to the X axis direction; Step 5: if the number of scanning ink jets is less than n, the ink jet vehicle repeats steps 3 and 4; if the number of scanning ink jets is equal to n, the printing is completed. C ink jets are a row different from the A ink jets or the B ink jets, and the ink jet vehicle realizes the position exchange of any two rows of the A ink jets, the B ink jets and the C ink jets along the Y axis direction by a displacement distance P.

2. A multi-PASS inkjet printer according to claim 1, wherein, The A ink jets and the B ink jets are arranged adjacently.

3. A multi-PASS inkjet printer according to claim 1, wherein The ink jet vehicle has an ink jet width I in the Y axis direction, which is at least one L more than the width H of a printing medium.

4. A multi-PASS inkjet printer according to claim 1, wherein The suspension structure comprises a driving device, the driving device and the ink jet vehicle are linear motors in the X axis and Y axis connection directions, and the driving device and the ink jet vehicle are lead screws in the Z axis connection direction.

5. A multi-PASS inkjet printer according to any of claims 1-4, characterized in that, The cleaning and maintaining assembly comprises an ink receiving groove arranged in the buffer space and used for receiving waste ink of the ink jet vehicle.

6. A multi-PASS inkjet printer according to any of claims 1-4, characterized in that, The cleaning and maintaining assembly further comprises a cleaning assembly arranged in the operating space and used for cleaning the ink jets on the ink jet vehicle.

7. A multi-PASS inkjet printer according to any of claims 1-4, characterized in that, The cleaning and maintaining assembly further comprises a moisturizing assembly arranged in the operating space and used for isolating and moisturizing the ink jets on the ink jet vehicle.

8. A multi-PASS inkjet printer according to claim 7, wherein, The cleaning and maintaining assembly further comprises a moisturizing film conveying assembly arranged in the operating space and used for replacing the moisturizing assembly.

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