Digital textile printing device and digital textile printing method

Abstract

A digital textile printing apparatus and method are disclosed, including placing a medium to be printed on a printing table and feeding towards a print head. A limited length of the medium proximate to the print head is measured to determine a number of variations in thickness towards the print head. Then, the height of the print head is adjusted to maintain a predetermined print distance. Subsequently, if the range reaches or exceeds the print distance, it is assumed that there are wrinkles and printing is suspended to re-adjust the medium, which can be a textile, in particular a garment.

Description

[0001] This application is a divisional application of application number 201980009114.3 (PCT application number PCT / IL2019 / 051389), filed on December 19, 2019, entitled "Height Control of Printhead".

[0002] Related applications This application claims priority to U.S. Provisional Patent Application No. 62 / 782353, filed December 20, 2018, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Some embodiments of the invention relate to printhead height control, and more specifically (but not limited to) measuring and controlling the height of the printhead on a textile substrate, particularly for direct-to-garment printing. Background Technology

[0004] In existing technologies, the printhead height control for a given print media height is defined manually by the printer operator or using an offline measuring device as part of predefined data for a print job. This method has many drawbacks and limitations and is highly sensitive to human error, such as inaccurate input, which can degrade overall print quality. Furthermore, even if multiple initial measurements are perfectly accurate, multiple variations in media height during the process can invalidate these initial measurements. These variations may be due to mechanical disturbances, such as multiple creases in the media or other irregularities in its surface, or inherent differences in the media itself, such as multiple strands or hairs protruding from the media. These problems can cause multiple nozzles of the printhead to come into contact with the media itself, or the print surface may not be perfectly flat. This contact can obstruct ink ejection from the nozzles and cause failed jets to dry on the nozzles, resulting in complete or partial blockage. While the design of multiple printheads can compensate for a small number of known faulty nozzles, over time, the process inevitably affects an increasing number of nozzles, thus shortening printhead life and increasing downtime.

[0005] A known method for detecting multiple inhomogeneities in a medium and protecting the system from multiple collisions between the medium and multiple printheads involves using a single, one-dimensional laser beam parallel to the medium. Once the medium height exceeds a preset maximum limit, the system detects the interference and typically stops the sequence immediately, accompanied by all the associated drawbacks of slower processing speed. While this avoids collisions, the entire printing process is affected because the printer stops mid-job. The current print operation becomes waste because it's impossible to restart the print job from the point of interruption. The operator needs to intervene, reset the system, and restart the job, resulting in a loss of valuable time.

[0006] Currently, media height measurement relies on multiple offline tools, and the measurement is performed offline, prior to the printing process. Instead of multiple actual measurements, various manual estimations or multiple platforms considering the specific media can be used. For some machines, the media type can be programmed, and the machine can use a lookup table to set the printhead height. Therefore, the current method is highly sensitive to user errors and media variations. The end result is reduced quality due to inaccurate print height or uneven surfaces, and the current solution cannot prevent collisions with the printhead due to uneven media.

[0007] To detect multiple wrinkles in a medium, current solutions utilize multiple mechanical modules that can detect adjacent wrinkles. In other solutions, a laser beam passing through the front of the printed area may also detect an adjacent fold.

[0008] The detector is set to a predefined value, which is typically unadjustable due to the binary nature of the concept, and scans the media in front of multiple printheads before or during the printing process to sense any protrusions or folds in the media that could potentially jeopardize the printheads. When such interference is detected, the printing process is stopped to avoid the risk of the media colliding with the printheads or other system components. The process is based on a "go / no-go" filter, meaning the media is below or above a maximum permissible value; if it is above this value, it interferes with the printing process. This inflexible process, which does not respond to multiple changes in a single print job's process, can negatively impact the overall user experience and system availability.

[0009] In the DTG (direct to garment) industry, when printing directly onto garments with inkjet printers, physical contact between the printhead and the garment itself must be avoided to prevent damage. Physical contact with the garment while hovering above it, especially at a speed of 1.0 m / s, can damage very expensive printheads. In some cases, this damage may be mitigated, but it is usually irreversible.

[0010] In the DTG industry, the mean time between failures (MTBF) of a system is of great value to customers, as a "head strike" can cause a lot of machine downtime and lengthy repairs.

[0011] One of the main causes of printhead collisions is garment misalignment, creating a "wrinkle" thicker than the gap between the printhead and the garment itself. Before printing, the gaps between multiple printheads and the garment are pre-set. Due to the wide variety of garment types, the printing height is also adjusted accordingly.

[0012] However, besides wrinkles, the height of the printing media can also vary. These variations might not be enough to collide with the printhead, but they could still alter the distance between the media and the printhead. Because of the relative motion between the printhead and the media, ink jets follow a ballistic trajectory. If the height between the media and the printhead changes, the ink jets will not land at the intended position, resulting in a decrease in print quality. Therefore, it is desirable to keep the distance between the printhead and the printing media as constant as possible during the printing process; however, current technology has no way to achieve this if the height of the printing media changes. Summary of the Invention

[0013] This embodiment relates to a method for adjusting the printhead height for printing operations based on measurements taken during and after the printing process to detect multiple wrinkles and other anomalies that may jeopardize multiple printheads.

[0014] The thickness and wrinkle detection system measures the thickness of the printing medium before printing and adjusts the printer height accordingly. The system can continue detecting multiple anomalies and thickness variations on the garment throughout the printer's workflow without requiring additional time in any inspection process, and the detection is performed before any part of the garment is printed. If a wrinkle is detected, the printing process is delayed, and the user is notified of the garment misalignment. Once the garment's position is corrected and it is returned to print, it is sent back for wrinkle detection to ensure it can be safely printed. Printing only resumes from the stopped position if it is safe to do so. As previously mentioned, multiple wrinkles and thickness variations can be detected using the same measurement method, which may involve a laser curtain to detect the contour of the upper surface adjacent to the garment, repeatedly measuring the contour over a finite distance of the advancing garment, typically on the order of 25-30 millimeters (mm).

[0015] According to one aspect of some embodiments of the present invention, a digital textile printing apparatus is provided, the digital textile printing apparatus comprising: One print head; A printing surface is configured to feed a medium for printing in a feed direction through which printing is performed by the printhead; A measuring unit is disposed downstream of the printhead in the feed direction for measuring a thickness of the medium used for printing, the measuring unit being configured to measure the thickness over a finite length of the printing medium toward the printhead in the feed direction.

[0016] In one embodiment, the measuring unit is configured to perform multiple thickness measurements over the finite length.

[0017] In one embodiment, the measurement unit is configured to repeatedly perform the plurality of measurements over a printing duration.

[0018] In one embodiment, the measuring unit includes a laser emitter and a laser collector.

[0019] In one embodiment, the measuring unit includes a laser curtain that extends over the finite length up to a predetermined thickness to measure a height profile of the textile.

[0020] In one embodiment, the printhead has an adjustable height and a controller for controlling the height, wherein the controller is responsive to the measuring unit to adjust the height based on a measured thickness close to the printing medium.

[0021] In one embodiment, the controller responds to multiple measured thicknesses within a predetermined range to perform the height adjustment, and interrupts printing when the measured thickness exceeds the predetermined range.

[0022] In one embodiment, the controller is configured to return to the print surface for readjustment when the measured thickness exceeds the predetermined range, then repeat the measurement, and resume printing if the measurement is within the predetermined range.

[0023] In one embodiment, the measuring unit is located next to a pre-printing processing unit in the feed direction of the printer.

[0024] In one embodiment, the printer is a garment direct-to-garment printer and the printing medium is a garment.

[0025] A second aspect of some embodiments of the present invention provides a digital textile printing method, the digital textile printing method comprising: Place the media to be printed on a printing table; Orient the medium toward a print head for printing; A range of the textile toward the printhead is measured along a finite length of the textile near the printhead in a thickness direction. Adjust the printhead to define a predetermined printing distance between the printhead and the textile for printing; and If the range reaches or exceeds the predetermined printing distance during printing, the printing is paused.

[0026] In one embodiment, the measurement includes performing multiple thickness measurements over the finite length.

[0027] In one embodiment, the measurement includes repeating the plurality of measurements over a printing duration.

[0028] In one embodiment, the measurement includes multiple irradiating laser beams passing through the textile.

[0029] In one embodiment, the measurement includes providing a laser curtain that extends over the finite length up to a predetermined thickness.

[0030] Multiple embodiments may include returning the print station for readjustment when the measured thickness reaches or exceeds the predetermined print distance, then repeating the measurement, and resuming printing if it is within the predetermined print distance.

[0031] Multiple embodiments may include performing the measurement on the printhead while pre-treating the textile in the feed direction.

[0032] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While similar or equivalent methods and materials to those described herein may be used in the practice or testing of embodiments of the invention, exemplary methods and / or materials are described below. In case of conflict, the patent specification, including its definitions, shall prevail. Furthermore, the materials, methods, and embodiments are illustrative only and are not intended to be necessarily limiting.

[0033] Implementation of the methods and / or systems of embodiments of the present invention may involve performing or completing selected tasks manually, automatically, or in a combination thereof. Furthermore, practical instruments and devices according to embodiments of the methods and / or systems of the present invention may use an operating system to implement several selected tasks through hardware, software, firmware, or a combination thereof.

[0034] For example, the hardware for performing a selected task according to an embodiment of the invention can be implemented as a chip or circuit. As software, the selected task according to an embodiment of the invention can be implemented as a plurality of software instructions executed by a computer using any suitable operating system. Attached Figure Description

[0035] This document describes some embodiments of the invention by way of example only, with reference to the accompanying drawings. Referring now specifically to the drawings, it should be emphasized that the details shown are for illustrative purposes and for a descriptive discussion of embodiments of the invention. In this regard, the accompanying drawings… Figure 1 The descriptions provided will be clear and understandable to those skilled in the art as to how embodiments of the invention can be practiced.

[0036] In the attached diagram: Figure 1 This is a simplified diagram illustrating a laser curtain spanning two printing stations according to an embodiment of the present invention; Figure 2 This is a simplified longitudinal cross-section of a printhead passing through a print station according to an embodiment of the present invention; Figure 3 yes Figure 2 The portion of the fold that enters the printing medium; Figure 4 This is a view of a printhead passing through and showing a portion of various height ranges according to an embodiment of the present invention; Figure 5 This is a simplified flowchart illustrating the process of modifying the printing procedure when a wrinkle is detected according to an embodiment of the present invention; Figure 6 yes Figure 2The section illustrates the addition of a laser curtain for measurement according to an embodiment of the present invention; Figure 7 yes Figure 6 One of the folds enters the printing medium; Figure 8 This is a simplified schematic diagram illustrating details of a control system for a printer according to this embodiment; Figure 9 This is a simplified diagram illustrating the use of a garment with a pocket, wherein such a garment can be printed according to this embodiment; Figure 10 It is a simplified diagram schematically illustrating the ballistic arc produced by a single ink droplet and providing the reason for maintaining a constant print height; and Figure 11 This is a general flowchart illustrating the printing process according to an embodiment of the present invention. Detailed Implementation

[0037] Some embodiments of the invention relate to measurement-based printhead height control, and more specifically (but not limited to) printhead height control based on measurements taken on a textile substrate.

[0038] It should be noted that the material printed on it is usually referred to as the medium, but more specifically it can be textiles, more specifically a garment, and the terms used in this article are interchangeable.

[0039] This embodiment may involve placing a textile piece to be printed on a printing table and feeding it toward a print head. A finite length of the textile piece adjacent to the print head is measured in an upward direction (i.e., facing the print head). Then, if the extent is within a predetermined range, the height of the print head is adjusted to maintain a predetermined printing distance. During printing, measurements continue, and if the thickness extent exceeds the predetermined range, multiple wrinkles are assumed to exist, and printing is paused to readjust the textile piece.

[0040] This embodiment treats multiple printheads as objects for height control based on measurements of the printing media. A single measurement procedure or a set of multiple measurements from a measurement source can simultaneously address issues of printing media height, correct positioning of multiple printheads, and the presence of multiple folds. The measurement procedure can repeatedly or continuously detect the media height in the printing process online. Multiple measurement results can be used to correct the print height before printing. In one particular embodiment, if the height changes, the print height can also be adjusted in real time during printing, meaning that the media approaches the printhead at a typical media feed rate, and as the media arrives, the printhead is set at the correct height. Regardless of whether the multiple printheads move, the measurements are performed on-the-fly. If the media thickness extends to the printhead's safety margin, for example through a fold in clothing, the procedure pauses the current printing, returns the media to the operator, and allows the operator to correct the problem and maintain the current job. The correction can have minimal impact on the overall printing operation.

[0041] In one embodiment, a laser curtain is used as a measuring component. A series of multiple laser beams are perpendicularly passed through the feed direction of the medium to form a rectangular or similar shape with a finite length and a predetermined height, along the adjacent textile, and the textile obtains a profile of the textile surface within the rectangle along the feed direction. A laser curtain is particularly suitable for finding a maximum height on the surface of a region of the material. Thus, the laser curtain can measure the profile, where multiple small deviations are input to change the height of multiple printheads, and multiple large changes can cause printing to temporarily stop. The measurement is performed in conjunction with the printer's workflow to detect misalignments (multiple wrinkles) that may ultimately lead to printhead collisions in the DTG printer.

[0042] Before explaining at least one embodiment of the present invention in detail, it should be understood that the present invention is not necessarily limited to the details of the construction and arrangement of the components and / or methods described in the following description and / or shown in the drawings and / or examples. The present invention can be implemented in various ways or other embodiments can be implemented.

[0043] Now, referring to the attached diagram, first refer to... Figure 1 , Figure 1 This is a simplified diagram showing a print stage and laser curtain in a cross-section along the printing feed direction according to an embodiment of the present invention. Two side-by-side print stages 100 and 102 transport their respective printing media 104 and 106 toward a print head 108. Figure 2 Printing is performed using a laser emitter 110 and a laser collector 112. The plurality of print stages are separated by a gap between a laser emitter 110 and a laser collector 112. A longitudinally extending laser curtain 114 extends for a finite length close to the print head in the feed direction.

[0044] Figure 2 This shows a longitudinal section of the printhead 108. The printhead 108 moves back and forth on the print table 100 on top of the media 104. The printhead is mounted above the print table at a height that includes the height of the media plus a predetermined printing height.

[0045] Therefore, the digital textile printing device can be a direct-to-garment digital printer with pre- and / or post-processing capabilities, and can print using black and white, or three, four, five, or more color systems. The printer may include a printhead 108 and one or more printing surfaces, such as... Figure 1 The diagram shows dual print tables or pallets 100 and 102. The plurality of surfaces are movable for feeding, with media passing through the printhead in a feeding direction for printing.

[0046] like Figure 1 As shown, the measuring unit, consisting of emitter 110 and collector 112, is located upstream of the printhead in the feed direction and extends vertically across the feed direction (see Figure 112). Figure 6 ), in a finite length (see Figure 6 The measuring unit measures the height of a printing medium in the feed direction to obtain a profile. The measurement may be of the upper portion of the textile facing the printhead in the thickness direction. To perform multiple measurements over a finite length rather than a straight line, the measuring unit may perform multiple thickness measurements over that finite length. The measuring unit may repeat the measurements over a printing duration to measure the advancing textile surface before approaching the printhead. In one embodiment, the measuring unit includes a laser emitter and a laser collector, and multiple laser beams irradiate the top of the printing medium surface across the finite length to detect the profile.

[0047] In one particular embodiment, the measuring unit includes a laser curtain extending up to a predetermined thickness along the finite length to measure a finite length and a finite height, hence the term curtain.

[0048] Embedded online laser curtains serve two main functions in garment direct-to-garment (DTG) printers: 1) Automatic printing height setting The first function is to automatically set the height of multiple printheads. This function involves measuring the actual height of the media before starting the printing program. In some embodiments, the function includes continuously remeasuring and defining the optimal height of multiple printheads above them during printing. This continuous print height setting ensures optimal print quality because it is highly sensitive to changes in the media. Furthermore, the operator can change the media on the printer without stopping the program for offline measurement and calibration. Additionally, printing is possible on media with sudden changes in thickness, such as a shirt with pockets. In other embodiments, if multiple wrinkles or multiple thickness variations are detected, continuous measurement during printing is used only to stop printing – see the second function below.

[0049] 2) Wrinkle detection and printhead collision avoidance The second function is automatic detection of multiple wrinkles. The same measurement can detect media-level interference, such as multiple wrinkles in textiles caused by human error or multiple system malfunctions in media placement, like an accidental loosening of a clamping component. If such a wrinkle is detected, this function can pause the current printing for a few seconds, allowing the operator to correct the problem without affecting the integrity of the job. The reason this embodiment can stop, wait for the operator to perform smoothing, and then continue is that the laser curtain in this embodiment can remeasure the entire area after smoothing, not just a line, and check whether the problem has been resolved. Now refer to... Figure 3 , and Figure 2 The view is the same as in the figure, but a fold 116 is introduced into the medium. The rest of the figure is given the same... Figure 2 The same reference numerals are used in the accompanying drawings, and will not be described again unless necessary for understanding the function of the folds. Figure 3 In this case, the folds 116 extend from the media height to just across the printing height. If the print head 108 is to reach the folds, the material in the folds may clog multiple nozzles on the print head, causing the damage described above.

[0050] Wrinkle detection can be used to avoid printhead collisions, thereby improving system uptime, i.e., print availability, as well as saving direct and indirect costs of damaged printheads and increasing the overall lifespan of the printhead.

[0051] Now for reference Figure 4 This illustrates a simplified cross-section of a rectangle or plane that can be measured by a laser curtain. Figure 4In this designation, the tray plane is represented by 120. The media plane is 122. The printing height plane is 124, and the printhead movement plane is 126. It should be noted that this embodiment can take into account the zero value of the print table tray. This has the following advantages: users are free to use a custom print table instead of the one provided by the printer, and do not need to ensure that the custom print table is a perfect match, or even a perfect match, with the print table provided by the printer.

[0052] Example values ​​for different planar dimensions are as follows Figure 4 As shown, the unit is millimeters. Therefore, the print height 124, the height between the media and the printhead can be 2 millimeters. Wrinkles 128 require a safety margin of 0.4 millimeters 130 below the printhead. That is, small wrinkles up to 1.6 millimeters can be tolerated.

[0053] Now for reference Figure 5 This diagram illustrates a simplified flowchart of the process for detecting and subsequently safely handling wrinkles. This embodiment can be used to detect wrinkles without controlling the printhead height, or vice versa, with controlled printhead height and no wrinkle protection. Figure 5 The process flow is shown after the print height has been set through an initial measurement. Operator 150 sends the current print job for printing. Box 152 determines whether wrinkle detection has been performed on the current print job. If yes, the process proceeds to box 154 to test for multiple wrinkles again. If no, the system determines whether wiping or other pre-printing processing has been requested – box 156. If no, the process proceeds to box 154 as described above. If the answer is "yes", the process proceeds to box 158, where measurement and pre-processing such as wiping are performed together. It is advantageous to perform measurement during and immediately after wiping, as simultaneous wiping and other pre-processing can affect the measured thickness, and in extreme cases, may even result in multiple wrinkles.

[0054] In box 160, it is determined whether a wrinkle has been detected. If no wrinkle is detected, the process proceeds to box 162, and printing proceeds or continues. On the other hand, if box 160 determines that a wrinkle has been detected, the process proceeds to box 164, printing is delayed, and the tray is returned to the operator for flattening.

[0055] The automatic height measurement described herein can be embedded in a garment direct-to-garment (DTG) printer. The system can be installed in the printer and can perform at least one or more of the following operations, or consecutively: (a) Measure the media height in real time and define the printing height; (b) Measure the flatness of multiple print stations and notify the user of any misaligned or uneven print stations to avoid reducing print quality; and (c) Detect the non-uniform surface of the medium (such as multiple folds on textiles) to avoid collision with the print head.

[0056] Therefore, this embodiment can use a laser device to measure garment thickness, with the measurement performed in conjunction with erasure or any other online pre-processing procedure. The embodiment can provide real-time notification when the thickness exceeds the permissible safe thickness. This prevents printhead collisions before actual printing. In the example above, if the media has already been processed and re-fed after wrinkle detection, then pre-processing is avoided. It is worth noting that in all cases, pre-processing is waived as long as erasure in block 156 is not requested, allowing the process to proceed directly to wrinkle detection.

[0057] Now for reference Figure 6 It demonstrates the use of a laser curtain. (And...) Figure 2 and Figure 3 The same reference numerals are assigned the same reference numerals throughout, and will not be repeated except as required by this description. The laser curtain 170 extends a finite length and a finite height along the feed direction of the media 104 toward the print head 108 to provide the longitudinal profile of the upper surface of the garment. The height of the print table is not directly measured during the printing process – although it can be measured in advance, multiple variations in the print table height will occur with multiple variations in the media thickness. The media height is continuously measured. The print height is preset and remains constant during multiple variations in the media height.

[0058] Using a laser curtain and inputting an analog signal to the printer's controller, a profile is measured along a length across an area of ​​the material. Typical lengths are between 20 mm and 40 mm or between 25 mm and 30 mm; in one exemplary embodiment, the length is 28 mm. The detection algorithm can be tailored to different garments.

[0059] The following parameters can be defined for the system: Reading – Real-time analog readings received from the laser device.

[0060] Pallet_Zero_Value – The value measured on an empty pallet (plate) without any garments, such as when changing a pallet or when such a measurement is initiated actively.

[0061] PresetMedia – The garment thickness preset by the user for the current print job.

[0062] PresetPrintHeight – The print height above the garment, preset by the user for the print job.

[0063] Constant – A constant clearance gap between multiple printheads and the measured medium.

[0064] You can execute about the system Figure 5 A wrinkle is detected during the erase or other preprocessing procedures discussed, or a dedicated measurement can be performed without preprocessing.

[0065] The example erase profile is set to a speed of 0.250 m / s. The pallet height may vary between a standard pallet height of 50 mm and a maximum pallet height of, for example, 90 mm. It typically starts from a preset and is then adjusted during printing.

[0066] Now for reference Figure 7 , Figure 7 yes Figure 6 A variation of the view shown. With Figure 6 The same parts are given the same reference numerals, and will not be described again unless necessary for understanding this embodiment. In this case, the laser curtain 170 has detected a fold 172. In this case, with Figure 3 Unlike before, the folds do not exceed the maximum media height. Therefore, simply move the print head 108 upwards to ensure the correct printing height is above the folds. Printing continues.

[0067] Now for reference Figure 8 , Figure 8 This is a simplified block diagram illustrating the operation of an embodiment of the present invention. A laser curtain is formed between a laser emitter 180 and a collector 182, capable of detecting the thickness or upper surface profile of a medium within the laser curtain area. An analog controller 184 operates a printhead height controller 186, which is subsequently controlled by system software 188. The control system ensures that if the measurement from the laser curtain is within a preset range, the printhead height controller 186 adjusts the printhead height to maintain a constant printing height. If the measurement exceeds the range, printing is temporarily stopped.

[0068] Therefore, the printhead has an adjustable height, and a controller, consisting of a combination of software 188, an analog controller 184, and a printhead height controller 186, adjusts the printhead height based on multiple measured changes in the thickness of the adjacent printing medium. If the measured thickness is within a predetermined range, printhead height adjustment is performed. However, if the measured thickness exceeds the range, the controller may stop printing.

[0069] Such as about Figure 5As discussed, when the measured thickness exceeds the predetermined range, the controller returns the print stage for the operator to readjust. After readjustment, the print stage is advanced again to repeat the measurement, and printing resumes if the thickness is within the predetermined range. If the measurement exceeds the range, the print stage is returned again.

[0070] As discussed earlier, the measurement unit can be located alongside a preprint preprocessing unit to measure any effects including preprocessing.

[0071] If the printer is a garment direct-to-garment printer, then the printing medium is a garment.

[0072] The laser unit, laser emitter, and laser collector can be easily mounted horizontally within the printer body to allow: Easy to calibrate laser beam alignment; The ability of lasers to detect any possible wrinkles; The ability to measure the presence or absence of clothing on the tray immediately after wiping; and Multiple pallets failed to provide complete positioning signals; A correct media (clothing) thickness preset is beneficial for defining the initial height of the printhead above the media during the printing operation.

[0073] The accurate height and flatness of the media help determine the optimal print height for the desired print quality and help avoid the printhead collisions discussed in this article. The print height above the media can be preset manually or manually verified offline by moving the print plate with the clothing under multiple printheads and visually inspecting for collisions.

[0074] By utilizing an embedded laser curtain and associated software, the system can measure the thickness of garments, particularly in the printed area. A test example achieved a resolution of 0.1 mm.

[0075] The maximum media thickness can be measured across the entire garment, regardless of the image printing area. Having such a pre-defined maximum garment thickness value means users don't need to manually check for collisions. Instead, the option to select multiple preset values ​​for print heights that might lead to collisions is disabled. Users are only allowed to preset safe print height values.

[0076] To improve the quality of printed images, a laser curtain can verify the media thickness during the preprocessing procedure. The actual media thickness is scanned across the image area, and the maximum thickness value is obtained across the entire media.

[0077] The printing height can then be automatically adjusted to suit preset media and printing height, and in some embodiments, it can be subsequently adjusted to take into account the maximum measured value, thereby avoiding collisions and maintaining the desired printing height. Now refer to... Figure 9 The illustration shows a garment 190 with two different heights, a background height, and an increased height at the sewn pocket 192. This embodiment allows for single-pass printing, where the print head is automatically adjusted when it reaches the pocket.

[0078] Now for reference Figure 10 , Figure 10 The operation of a printhead according to this embodiment is shown, and the requirement for a constant or substantially constant print height in textile printing is illustrated.

[0079] like Figure 10 As shown, garment 200 is located on print table 202, and printhead 204 is positioned at a predetermined distance from the garment. During printing, the printhead typically moves from one side of the garment to the other. In some machines, the printhead may remain stationary, but the print tray can move. Therefore, the inkjet 206 emitted from the printhead follows a ballistic trajectory from the nozzle to the garment. Now, if the printhead speed and print height are both constant, the position of the inkjet on the garment is fixed. However, once the print height begins to change, the portion of the ballistic arc at the point where the inkjet impacts the garment changes, and therefore the position becomes unpredictable. Thus, changes in print height lead to a loss of print quality, and therefore this embodiment attempts to control the height of the printhead.

[0080] Now for reference Figure 11 , Figure 11 This is a simplified flowchart illustrating the overall process for printing textiles according to an embodiment of the invention, and more specifically (but not limited to) direct-to-garment printing.

[0081] The textile to be printed (e.g., a garment) is placed on a printing surface such as a printing table, a tray, or a pallet – box 210. The garment may optionally be smoothed by an operator on the garment surface so that no wrinkles affect the printing process – box 212.

[0082] The textile is then fed toward the print head for printing – box 214. Various pretreatment operations, such as humidification – 216, can be performed during the feeding process. It is important to note that pretreatment should not be performed twice on the same garment; therefore, if the currently fed garment has already been pretreated, for example, because it is being fed a second time after wrinkle removal, the pretreatment operation will be bypassed. Alternatively, in this embodiment, pretreatment may not be necessary at all.

[0083] As the textile is being fed in, the height of a finite length of the textile near the printhead is measured, i.e., the height it extends toward the printhead – 218. In other words, the uppermost extent of the textile toward the printhead is measured over a given length, and the print height is adjusted accordingly – 220. The measurement may involve performing multiple thickness measurements over said given length, and in 221, the measurements can continue and be repeated over a print duration. In an embodiment, the measurement may involve irradiating multiple laser beams across the surface of the textile, such that blocked beams indicate the presence of textile material of that thickness. In one embodiment, a laser curtain provides a rectangular array of multiple laser beams extending up to a predetermined thickness over said given length, thereby obtaining a profile of the upper surface of the textile.

[0084] In decision box 222, test whether the measured height is safe; in this case, proceed to print 226.

[0085] If the area exceeds the predetermined range, the wrinkle-handling procedure is initiated. Box 224 indicates that printing is paused when the print table is returned to the operator to repeat the flattening operation 212.

[0086] Printing begins when the process enters box 226, and measurements continue as more garments are fed into the printer.

[0087] It is anticipated that many related laser curtain and textile printing technologies will be developed during the patent terminology period of this application, and the scope of the corresponding terminology is intended to include all such prior new technologies.

[0088] The terms “comprises,” “comprising,” “includes,” and “including,” and their suffixes, mean “including but not limited to.”

[0089] The phrase “consisting of” means “including and limited to”.

[0090] As used herein, the singular forms “a” and “the” include plural references unless the context clearly indicates otherwise.

[0091] It should be understood that, for clarity, certain features of the invention described in the context of a single embodiment may also be provided in combination in a single embodiment, and the text will be interpreted as if explicitly and in detail in such a single embodiment. Conversely, for brevity, various features of the invention described in the context of a single embodiment may also be provided individually or in any suitable sub-combination, or suitably provided in any other described embodiment of the invention, and the text should be understood as explicitly and in detail set forth in this document.

[0092] Certain features described in the context of various embodiments are not considered essential features of these embodiments, unless the embodiment would not function without these elements.

[0093] Although the invention has been described in conjunction with specific embodiments thereof, it will be apparent to those skilled in the art that many alternatives, modifications, and variations will be apparent. Therefore, this application is intended to include all such alternatives, modifications, and variations that fall within the spirit and broad scope of the appended claims.

[0094] All publications, patents, and patent applications mentioned in this specification are incorporated herein by reference in their entirety to the same extent as if each individual publication, patent, or patent application were specifically and individually indicated to be incorporated herein by reference. Furthermore, any reference or designation of any reference in this application should not be construed as an admission that such reference is available as prior art to the invention. The use of section headings should not be construed as an inherent limitation.

[0095] Furthermore, any priority documents in this application are incorporated herein by reference.

Claims

1. A digital textile printing device, characterized in that, The digital textile printing device includes: A printhead is mounted on an adjustable mounting base; A printing surface is configured to feed a medium for printing in a feed direction through which printing is performed by the printhead; A measuring unit, disposed upstream of the printhead in the feed direction, is configured to measure a thickness profile of the medium used for printing. The measuring unit is configured to measure the thickness profile perpendicular to the feed direction along a finite length toward the printhead in the feed direction of the printing medium while the medium is being fed into the printhead for printing. The measuring unit is configured to perform multiple thickness measurements and is configured to form a laser curtain along a finite length in the feed direction and perpendicular to the feed direction, thereby enabling the acquisition of a height side profile of the medium. The measuring unit thereby obtains the longitudinal profile of the upper surface of the printing medium from the height profile, and the measuring unit further detects the tray zero value corresponding to the printing surface.

2. The digital textile printing apparatus as described in claim 1, characterized in that, The printhead has an adjustable height and a controller for controlling the height. The controller is responsive to the measuring unit to adjust the height based on a measured thickness close to the printing medium. The adjustment is performed when the measured thickness is within a predetermined range. The controller is configured to interrupt printing when the measured thickness exceeds the predetermined range and to dynamically adjust the height of the printhead based on changes in the height profile during the feeding process.

3. The digital textile printing apparatus as described in claim 2, characterized in that, The controller is configured to return to the print surface for readjustment when the measured thickness exceeds the predetermined range, then repeat the measurement, and resume printing if the measurement is within the predetermined range.

4. The digital textile printing apparatus as described in claim 2, characterized in that, The measuring unit is located next to a pre-printing processing unit in the feed direction of the printer.

5. The digital textile printing apparatus as described in claim 2, characterized in that, The printer is a garment direct-to-garment printer, and the printing medium is a garment.

6. A digital textile printing device, characterized in that, The digital textile printing device includes: A printhead is mounted on an adjustable mounting base; A printing surface is configured to feed a medium for printing in a feed direction through which printing is performed by the printhead; A measuring unit, disposed upstream of the printhead in the feed direction, is configured to measure a thickness profile of the medium used for printing. The measuring unit is configured to measure the thickness profile perpendicular to the feed direction along a finite length toward the printhead in the feed direction of the printing medium while the medium is being fed into the printhead for printing. The measuring unit is configured to perform multiple thickness measurements and is configured to form a laser curtain along a finite length in the feed direction and perpendicular to the feed direction, thereby enabling the acquisition of a height side profile of the medium. The printhead has an adjustable height and a controller for controlling the height. The controller is responsive to the measuring unit to adjust the height based on a measured thickness approaching the printing medium. The adjustment is made when the measured thickness is within a predetermined range, and the controller is configured to interrupt printing when the measured thickness exceeds the predetermined range. The measuring unit thereby obtains the longitudinal profile of the upper surface of the printing medium from the height profile, and dynamically adjusts the height of the print head according to the changes in the height profile during the feeding process; and the controller is configured to change the amount of distance by which the print head is moved away from the medium through the height adjustment.

7. The digital textile printing apparatus as described in claim 6, characterized in that, The printer is a garment direct-to-garment printer, and the printing medium is a garment.

8. A digital textile printing method, characterized in that, The digital textile printing method includes: Place the textile media to be printed on a printing table; The textile medium is fed toward a print head for printing; During feeding, a laser beam is projected onto the textile near the printhead at multiple discrete points within a finite length along the feeding direction and in a height direction perpendicular to the feeding direction to form a two-dimensional laser curtain. The two-dimensional laser curtain is rectangular and is used to measure the extent to which the textile medium extends toward the printhead in its thickness direction. The multiple discrete points form the two-dimensional laser curtain to obtain the longitudinal profile of the upper surface of the textile. Detect the zero position of the printing station.

9. The method as described in claim 8, characterized in that, The method further includes: Obtain the thickness profile and measure the extent to which the textile extends toward the printhead in its thickness direction; During printing, the print head is dynamically adjusted based on the thickness profile to define a predetermined printing distance between the print head and the textile; and During printing, if the extension exceeds the predetermined printing distance, the printing is paused.

10. The method as described in claim 8, characterized in that, The measurement involves irradiating the textile with a laser beam across it.

11. The method as described in claim 8, characterized in that, The two-dimensional laser curtain extends to a predetermined thickness over the finite length.

12. The method as described in claim 8, characterized in that, The method includes: when the measured thickness reaches or exceeds the predetermined printing distance, returning the printing table for readjustment; then repeating the measurement; and resuming printing when the measurement result is within the predetermined printing distance range.

13. The method as described in claim 8, characterized in that, The method includes performing the measurement on the textile in the feed direction while pre-treating the textile.

14. The method according to any one of claims 8 to 13, characterized in that, The printing is direct-to-garment printing, and the textile medium being printed is a garment.

15. A digital textile printing method, characterized in that, The digital textile printing method includes: Place the textile media to be printed on a printing table; The textile medium is fed toward a print head for printing; During feeding, a laser beam is projected onto the textile near the printhead at multiple discrete points within a finite length along the feeding direction and in a height direction perpendicular to the feeding direction to form a two-dimensional laser curtain. The two-dimensional laser curtain is rectangular and is used to measure the extent to which the textile medium extends toward the printhead in its thickness direction. The multiple discrete points form the two-dimensional laser curtain to obtain the longitudinal profile of the upper surface of the textile. Obtain the thickness profile and measure the extent to which the textile extends toward the printhead in the thickness direction of the textile medium; During printing, the print head is dynamically adjusted based on the thickness profile to limit a predetermined printing distance between the print head and the textile. Dynamically adjust the predetermined printing distance used for printing; and During printing, if the extension exceeds the predetermined printing distance, the printing is paused.

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