WO2009128572A1 - Système d'impression - Google Patents

Système d'impression Download PDF

Info

Publication number
WO2009128572A1
WO2009128572A1 PCT/KR2008/002119 KR2008002119W WO2009128572A1 WO 2009128572 A1 WO2009128572 A1 WO 2009128572A1 KR 2008002119 W KR2008002119 W KR 2008002119W WO 2009128572 A1 WO2009128572 A1 WO 2009128572A1
Authority
WO
WIPO (PCT)
Prior art keywords
ink
trigger signal
signal pulse
images
controller
Prior art date
Application number
PCT/KR2008/002119
Other languages
English (en)
Inventor
Kye Si Kwon
Original Assignee
Soonchunhyang University Industry Academy Cooperation Foundation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Soonchunhyang University Industry Academy Cooperation Foundation filed Critical Soonchunhyang University Industry Academy Cooperation Foundation
Priority to KR1020107022955A priority Critical patent/KR101207888B1/ko
Priority to PCT/KR2008/002119 priority patent/WO2009128572A1/fr
Publication of WO2009128572A1 publication Critical patent/WO2009128572A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04581—Control methods or devices therefor, e.g. driver circuits, control circuits controlling heads based on piezoelectric elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04508—Control methods or devices therefor, e.g. driver circuits, control circuits aiming at correcting other parameters

Definitions

  • Figure 1 shows a schematic block diagram of one embodiment of an apparatus capable of measuring ink motion.
  • Figure 2 shows an example of a voltage waveform used to drive a print head in one embodiment.
  • Figure 3 shows an example of an application program display showing the operation of measuring ink motion in one embodiment.
  • Figure 4 shows an example diagram illustrating images of the meniscus of the ink for two different delays, T 1 (upper figure) and T 2 (lower figure), between the first and second control signal pulses.
  • Figure 5 is a schematic graph illustrating the meniscus motion obtained in one embodiment.
  • Figure 6 is a schematic graph that illustrates one example of a basic waveform used for measuring ink motion in one embodiment.
  • Figure 7 is a schematic graph that illustrates another example of a basic waveform used for measuring ink motion in one embodiment.
  • Figure 8 is a schematic graph that illustrates one example of designing a waveform in one embodiment.
  • Figure 9 is a schematic graph that illustrates another example of designing a waveform in one embodiment.
  • Figure 10 is a schematic graph that illustrates still another example of designing a waveform in one embodiment.
  • Figure 11 is a flow chart that illustrates a method of measuring the motion of an ink, according to one embodiment.
  • Figure 12 is a flow chart that illustrates a method of diagnosing an inkjet printing device, according to one embodiment.
  • Figure 13 is a flow chart that illustrates a method of designing a waveform for driving a printing device, according to one embodiment.
  • BACKGROUND [16] Recent developments in inkjet printing technology have led to the application of the technology to display manufacturing processes, as well as office printers. InkJet printing technology makes use of ink droplets to form specific patterns on a target object, such as a sheet of paper, or other substrate.
  • inkjet printing technology it is possible to control the volume of a droplet from an inkjet print head to an accuracy of a few picolitres and the location of a droplet on the target object to an accuracy of a few micrometers. Due to these features, inkjet technology has emerged as a powerful tool for patterning electronics devices, such as large area display applications, radio frequency identification (RFID), printed circuit board (PCB) patterning, and the like.
  • RFID radio frequency identification
  • PCB printed circuit board
  • jetting performance such as droplet speed and droplet volume
  • the jetting performance of inkjet printing may depend on the viscosity of the ink, print head, printing speed, printing environment, and the like.
  • extensive research has been conducted to implement a printing head having nozzles that are well calibrated and consistent with jetting performance under a given environment, where uniform patterning is obtained throughout the substrate. For example, the speed of each droplet or the volume of the nozzle can be scanned and the input voltage of each nozzle may be adjusted accordingly before any patterning process is performed.
  • the print head may fail to jet the ink from the nozzle, in which case the lack of ink droplets may make it impossible to adjust the nozzle.
  • an apparatus includes a controller configured to generate a first control signal, a pulse generator configured to generate a first trigger signal pulse and a second trigger signal pulse based on the first control signal, a second control signal pulse being generated after a variable delay to the first trigger signal pulse, a waveform generator configured to generate a waveform to drive a printing device based on the first trigger signal pulse, a lighting unit configured to illuminate ink in the printing device based on the second trigger signal pulse, and an image capturing unit configured to capture a plurality of images of the ink, each image captured for a different delay between the first and second trigger signal pulses.
  • the apparatus 100 includes a print head 102, a lighting unit 104, a lighting unit driver 106, an image capturing unit 108, a controller 110, and a print head driver 112.
  • the lighting unit 104 may include a light emitting diode (LED), a laser diode (LD), or the like
  • the image capturing unit 108 may include any type of camera, such as a charge-coupled device (CCD) camera and the like.
  • the print head 102 may include any form of inkjet print head, such as a piezo inkjet head and the like.
  • Each of the components 102, 104, 106, 108, 110, and 112 may be provided on a single device or spread over several devices depending on the implementation.
  • the controller 110, the lighting unit driver 106, and the print head driver 112 may be implemented in a single integrated device with the lighting unit 104 and the image capturing unit 108.
  • the controller 110, the lighting unit driver 106, and the print head driver 112 may be implemented in a separable device detachable from a device or devices embedding the lighting unit 104 and the image capturing unit 108.
  • the print head 102 may be installed in a separate device (e.g., a printer) or integrated with the controller 110.
  • the print head driver 112 may include a trigger signal pulse generator 114 and a waveform generator 116.
  • the controller 110 may control the operations of the print head driver 112 by e g., transmitting a control signal to the print head driver 112. Under the control of the controller 110 (e.g., upon receiving the control signal), the print head driver 112 causes the trigger signal pulse generator 114 to generate first and second trigger signal pulses 118 and 120 that are provided to the waveform generator 116 and the lighting unit driver 106, respectively.
  • the trigger signal pulse generator 114 can be installed as a separate unit exterior to the print head driver 112. In this case, the trigger signal pulse generator 114 can link the controller 110 to the print head driver 112 through an interface, such as a wired line connection.
  • the trigger signal pulse generator 114 provides the first trigger signal pulses to the waveform generator 116.
  • the trigger signal pulse generator 114 may control the first trigger signal pulse 118 to have a certain frequency, e.g., 1 kHz, under the control of the controller 110.
  • the controller 110 may execute an application software program or receive a user input to determine the frequency of the first trigger signal pulse 118.
  • the trigger signal pulse generator 114 may be implemented with counters in a multi- function Input/Output unit.
  • the trigger signal pulse generator 114 may generate a second trigger signal pulse 120 triggered by the first trigger signal pulse 118.
  • the second trigger signal pulse 120 is generated to have a delay T 1 relative to the first trigger signal pulse 118.
  • the delay T 1 between the first and second trigger signal pulses 118 and 120 can be variable, e.g., according to the setting provided by a user and/or control by the controller 110. That is, the delay T 1 can be adjusted manually or automatically via an algorithm executed by the controller 110, upon receiving a user input. In this way, the controller 110 can control the operations of the print head 102 and the lighting unit 104 in a time- varying sequential fashion. In other words, the controller 110 may control the lighting unit 104 to operate after the delay T 1 to the operation of the print head 102.
  • the trigger signal pulse generator 114 delivers the first trigger signal pulse 118 to the waveform generator 116.
  • the waveform generator 116 may generate a waveform for driving the print head 102.
  • Figure 2 shows an example of the voltage waveform used to drive the inkjet print head 102, in one embodiment.
  • the waveform can be characterized by a rising time, a falling time, a dwell time, and the like, where these characteristics may be adjusted according to the requirements of the apparatus 100.
  • the controller 110 may generate waveform data and send the data to the waveform generator 116 through an interface such as a general purpose interface bus (GPIB).
  • GPIB general purpose interface bus
  • the waveform generator 116 may have a sampling frequency of up to, e.g., 15 MHz, in which case the waveform generator 116 may make as many as 15 data points per microsecond ( ⁇ s) to define the driving waveform voltage.
  • the waveform generator 116 applies the waveform to the print head 102 having a nozzle that contains the ink.
  • the nozzle of the print head 102 may have various diameters depending on its application field and/or design requirements. For example, the nozzle diameter may have the order of approximately tens of ⁇ m, such as 50 ⁇ m.
  • Various inks such as a nano silver ink with nanoparticles of approximately 10 nm diameter dissolved in de-ionized water, may be used as the jetting material of the ink.
  • the lighting unit driver 106 receives the second trigger signal pulse 120 to drive the lighting unit 104.
  • the lighting unit driver 106 may control the lighting unit 104 to illuminate the ink contained in the nozzle of the print head 102 and the image capturing unit 108 to start capturing the images of the ink.
  • the image capturing unit 108 may take a picture of the meniscus motion of the ink when the ink is illuminated by the lighting unit 104.
  • a user may operate the controller 110 to adjust the lighting unit 104 so that the image capturing unit 108 may capture images of the meniscus motion of the ink automatically.
  • the image capturing unit 108 delivers the images to the controller 110 by using various interfaces between the image capturing unit 108 and the controller 110 including, but not limited to, a wired line, a cable, a wireless connection, or any other interface methods.
  • the controller 110 may process the images to generate a graph showing the meniscus motion of the ink and deliver the graph to a display (not shown) that displays the graph, for example, for the user's reference.
  • the images may be transmitted from the image capturing unit 108 to the controller 110 using a wired communication protocol, a wireless communication protocol, or a combination thereof.
  • the wired or wireless communication protocol may be implemented by employing a digital interface protocol, such as a serial port, parallel port, PS/2 port, universal serial bus (USB) link, firewire/IEEE 1394 link, or a wireless interface connection, such as an infra-red interface, BloothTooth, ZigBee, high definition multimedia interface (HDMI), high-bandwidth digital contents projection (HDCP), wireless fidelity (Wi-Fi), or the like.
  • a digital interface protocol such as a serial port, parallel port, PS/2 port, universal serial bus (USB) link, firewire/IEEE 1394 link, or a wireless interface connection, such as an infra-red interface, BloothTooth, ZigBee, high definition multimedia interface (HDMI), high-bandwidth digital contents projection (HDCP), wireless fidelity (Wi-Fi), or the like.
  • the apparatus 100 may be configured with a suitable operating system to install and run executable codes, programs, etc. from one or more computer readable media, such as a floppy disk, CD-ROM, DVD, a detachable memory, a USB memory, a memory stick, a memory card, or the like.
  • a suitable operating system to install and run executable codes, programs, etc. from one or more computer readable media, such as a floppy disk, CD-ROM, DVD, a detachable memory, a USB memory, a memory stick, a memory card, or the like.
  • FIG. 3 shows an example of an application program display 300 showing the operation of measuring ink motion in one embodiment.
  • the application program display 300 may include an edge coordinate indicator 302, a detected edge display 304, a threshold controller 306, an image viewer 308, a graph viewer 310, a start button 312, an operational interface 314, a save button 316, and an end button 318.
  • a user may set the operational parameters through the operational interface 314 to determine the delay T 1 between the first and second trigger signal pulses 118 and 120. For example, as shown in Figure 3, a user may set the start time of the delay T 1 to be 2 ⁇ sec, the end time to be 400 ⁇ sec, the increment time to be 2 ⁇ sec, and the average number of capturing images for one increment time to be 5.
  • the user may initiate the measuring operation by pressing the start button 312.
  • the controller 110 may generate a control signal to cause the trigger signal pulse generator 114 to variably adjust the delay T 1 between the first and second trigger signal pulses 118 and 120 that are provided to the print head 102 and the lighting unit 104, respectively.
  • the image capturing unit 108 may capture images of the meniscus motion of the ink when the lighting unit 104 illuminates the ink driven by the second trigger signal pulse 120 having different values of delay T 1 relative to the first trigger signal pulse 118 at a given time.
  • the progress bar indicates the progress of the measuring operation, and the user may save the images by pressing the save button 316 and end the operation by pressing the end button 318.
  • the image viewer 308 shows each of the images captured at a different delay T 1 .
  • the controller 110 may apply a numerical operation (e.g., an edge detection algorithm) to each of the images to detect discontinuities in the pixel intensity of the image along a reference line in the image viewer 308.
  • the controller 110 uses the edge detection technique to obtain information about the location of the ink boundaries along the reference line.
  • the detected edge display 304 shows the edge boundary of the ink for the image displayed in the image viewer 308, while the edge coordinate indicator 302 displays the X-Y coordinates of the detected edge along the reference line.
  • the controller 100 may determine a region of interest (ROI) to confine the target area to be processed in the image.
  • ROI region of interest
  • the controller 110 may define the ROI by the reference line in the image that selects the pixel data to be analyzed, as shown in Figure 3.
  • the controller 110 may set an area having a certain shape as the ROI, as shown in Figure 4.
  • a rectangular shape is illustrated as the ROI in Figure 4, the shape of the ROI can be adjusted according to the implementation requirements and includes, but is not limited to, a circle, an eclipse, a triangle, or the like.
  • the controller 110 may execute a software program that is developed such that the ROI can be specified either interactively or program- matically.
  • the ROI includes image pixels having values that vary, e.g., from 0 to 255, according to the brightness of the image.
  • the controller 110 may detect the edge locations of the meniscus of the ink, where the image pixel values cross the threshold value.
  • a user may determine the threshold value by operating the threshold controller 306 of the application program display 300.
  • FIG. 4 an example diagram illustrating the meniscus motion of the ink for two different delays, T 1 (upper figure) and T 2 (lower figure), between the first and second trigger signal pulses 118 and 120 is illustrated.
  • the trigger signal pulse generator 114 applies the first trigger signal pulse 118 to the waveform generator 116 to generate a waveform for driving the print head 102, and the second trigger signal pulse 120 to the lighting unit driver 106 for driving the lighting unit 104, under the command or instructions of the controller 110.
  • the image capturing unit 108 captures images of the meniscus of the ink at the time when the lighting unit 104 illuminates the ink in the print head 102, and stores the images in a storing unit.
  • the controller 110 may retrieve the stored images and perform the edge detection algorithm on the images. As shown in Figure 4, the controller 110 may display two images of the meniscus of the ink for the delays T 1 and T 2 , where it can be seen that the meniscus of the ink moves downward as the delay changes from T 1 to T 2 .
  • the graph viewer 310 displays a graph showing the meniscus motion of the ink as the delay changes as time lapses.
  • the delay may change according to the setting specified by, e.g., a user through the operational interface 314, or by executing a software program that is designed to adjust the meniscus motion measurement process, or the like.
  • the horizontal axis (i.e., the X axis) of the graph indicates the time of the delay ( ⁇ sec) whereas the vertical axis (i.e., the Y axis) of the graph represents the vibrating amplitude of the meniscus motion of the ink.
  • the amplitude of the meniscus motion may be indicated as having a negative value relative to the predetermined reference amplitude for the convenience of the display.
  • Each point in the graph is linked by collecting boundary locations on the reference line that are detected through the edge detection algorithm by varying the delay between the first and second trigger signal pulses 118 and 120.
  • the fluctuation of the graph displays the meniscus motion of the ink along the reference line. For example, as the graph fluctuates upward in the graph viewer 310, the meniscus of the ink moves downward along the reference line in the image viewer 308, which also means that the detected edge displayed in the detected edge display 304 moves leftward (i.e., the Y coordinate value in the edge coordinate indicator 302 decreases).
  • FIG. 5 a schematic graph illustrating the meniscus motion obtained in one embodiment is illustrated.
  • the graph of the meniscus motion may vibrate for a period of time and have an exponentially decaying form as time passes.
  • the controller 110 may analyze the graph of the meniscus motion to obtain the characteristics of the meniscus motion, such as damping ratio, peak amplitude, and the like.
  • the controller 110 may perform a numerical analysis on the characteristics of the meniscus motion by modeling the meniscus motion with a mathematical equation, as shown below:
  • the controller 110 may estimate the status of the ink and the print head 102, based on the characteristics of the meniscus motion of the ink. For example, the controller 110 may interpret the meniscus motion as follows: (i) a larger peak amplitude to mean a stronger pressure (i.e., a larger voltage) for jetting the ink (i.e., easy jetting); (ii) a higher damping ratio (i.e., larger ⁇
  • the controller 110 may diagnose the operation of the print head 102 and the status of the ink used in the print head 102 from the analyzed results of the graph.
  • the controller 110 may detect abnormal jetting conditions, such as bubbles trapped in the print head 102, by observing the peak amplitude, and measure the ink material status, such as viscosity, speed of sound, and the like, by observing the damping ratio and the period from the graph. For example, when the controller 110 determines that the peak amplitude is small, the controller 110 may display an indicator showing that the pressure for jetting the ink needs to be increased. Further, when the controller 110 determines that the damping ratio is high, the controller 110 may display an indicator showing that the viscosity of the ink needs to be reduced.
  • FIG. 6 and 7 schematic graphs that illustrate examples of basic waveforms for measuring the meniscus motion of the ink for waveform designs are illustrated.
  • the controller 110 delivers a control signal to cause the print head driver 112 to generate the basic waveforms for driving the print head 102.
  • An amplitude of the basic waveforms may have negative and positive signs as shown in Figures 6 and 7, respectively. That is, the amplitude of the basic waveforms may be above or below a reference level indicated by a horizontal axis (i.e., X axis) of the graphs.
  • the basic waveforms may have falling and rising times having predetermined values, e.g., 2-10 ⁇ sec.
  • the waveform generator 116 in the print head driver 112 may generate a basic waveform having a large dwell time, e.g., more than 30 ⁇ sec.
  • the positively signed basic waveform of Figure 7 may be generated with a certain delay relative to the negatively signed basic waveform of Figure 6.
  • the controller 110 may measure the meniscus motion of the ink to display graphs of the meniscus motion for the two basic waveforms, as shown in Figures 6 and 7. Further, the controller 110 may use the measured meniscus motions to modify the basic waveforms to design new waveforms. For example, based on the measured meniscus motion, the controller 110 may determine the voltage amplitude and the dwell time of the new waveform.
  • the controller 110 measures the characteristics of the meniscus motion of the ink, such as the period, peak amplitude, and damping ratio, and uses the characteristics to design a new waveform. For example, the controller 110 may determine the dwell time of the waveform to be the period of the meniscus motion, and determine the voltage amplitude of the waveform according to the peak amplitude of the meniscus motion.
  • FIG. 8 shows an example where the controller 110 determines that the amplitude of the meniscus motion will be sufficient for jetting ink from the print head 102.
  • the controller 110 causes the waveform generator 116 to generate a waveform having a dwell time equal to the period of the meniscus motion T.
  • the controller 110 triggers the waveform generator 116 to generate the basic waveform shown in Figure 6 and, after the delay T, triggers the waveform generator 116 to generate the basic waveform shown in Figure 7 (see upper figure of Figure 8).
  • the waveform generator 116 may generate a waveform that cancels out the meniscus vibration after jetting ink (see lower figure of Figure 8), while maintaining the peak amplitude of the meniscus motion.
  • the print head 102 may initiate the jetting of the ink when the voltage level increases.
  • FIG. 9 shows an example where the controller 110 determines that the amplitude of the meniscus motion will not be sufficient for jetting ink from the print head 102.
  • the controller 110 causes the waveform generator 116 to generate a waveform having a dwell time equal to half the period (772) of the meniscus motion T. That is, the controller 110 triggers the waveform generator 116 to generate the basic waveform shown in Figure 6 with a sign inversion and, after the delay 7/2, triggers the waveform generator 116 to generate the basic waveform shown in Figure 7 with a sign inversion (see upper figure of Figure 9).
  • the sign inversion can be implemented by applying a voltage opposite to the voltage applied to generate the basic waveforms.
  • the waveform generator 116 may generate a waveform that has an amplified amplitude sufficient to jet ink (see lower figure of Figure 9).
  • the amplified waveform can increase the pressure wave applied to the print head 102.
  • the pressure wave can be doubled or at least amplified to sufficiently initiate the jetting of the ink from the print head 102.
  • Figure 10 shows an example where the controller 110 determines that the amplitude of the meniscus motion is not sufficient for jetting ink from the print head 102, and that the meniscus vibration after jetting ink needs to be canceled.
  • the waveform generator 116 generates a waveform having a dwell time of the period of T/2 in a similar fashion as illustrated in Figure 9, and then generates a waveform having a dwell time of the period of T in a similar fashion as illustrated in Figure 8 (see upper figure of Figure 10).
  • the waveform generator 116 may generate a waveform that has an amplified amplitude sufficient to jet ink and cancels out the meniscus vibration after jetting ink (see lower figure of Figure 10).
  • the trigger signal pulse generator 114 in the print head driver 112 applies the first trigger signal pulse 118 to the waveform generator 116 (see also Figure 1).
  • a user may use a software program to execute the operations that are run by a computing device.
  • the waveform generator 116 in the print head driver 112 may generate basic waveforms, such as the waveforms shown in Figures 6 and 7. In this way, the print head driver 112 may apply the first trigger signal pulse 118 to the print head 102 to cause the meniscus motion of the ink.
  • the print head driver 112 may adjust the amplitude of the waveform (i.e., the voltage level) not to allow the print head 102 to jet the ink so that no droplets appear from the print head 102 during the measurement of the meniscus motion.
  • the trigger signal pulse generator 114 in the print head driver 112 applies the second trigger signal pulse 120 to the lighting unit driver 106 for driving the lighting unit 104.
  • the trigger signal pulse generator 114 retards the second trigger signal pulse 120 from the first trigger signal pulse 118 by the delay T 1 .
  • the trigger signal pulse generator 114 may increase the delay by a unit of, e.g., 2 ⁇ sec, based on the input by a user through the software program as shown in Figure 3.
  • the image capturing unit 108 captures images of the meniscus motion of the ink that is contained in the print head 102.
  • the image capturing unit 108 captures each image of the ink illuminated by the lighting unit 104 that is driven by the second trigger signal pulse 120 having a given delay T 1 relative to the first control signal pulse 118.
  • the image capturing unit 108 may obtain a still shot (i.e., a frozen image) of the meniscus motion of the ink.
  • the image capturing unit 108 may capture images of the ink at different time points.
  • the image capturing unit 108 may store the images in a storing unit such as RAM, ROM, CD-ROM, and the like.
  • the lighting unit 104 may include a light emitting diode (LED), a laser diode (LD), or the like, while the image capturing unit 108 may include any type of camera, such as a charge-coupled device (CCD) camera.
  • CCD charge-coupled device
  • the controller 110 carries out an image processing on the images obtained by the image capturing unit 108.
  • the controller 110 may apply a numerical operation (e.g., an edge detection algorithm) to each of the images to detect discontinuities in the pixel intensity of the image along a reference line.
  • the controller 110 uses edge detection techniques to obtain information about the location of the ink boundaries in each image of the ink.
  • the controller 110 may display the image of the ink on a display by using an application program as shown in Figure 3.
  • the detected edge display 304 shows the edge boundary of the ink for the image displayed in the image viewer 308, while the edge coordinate indicator 302 indicates the X-Y coordinates of the detected edge.
  • the controller 100 may determine a region of interest (ROI) to confine the target area to be processed in the image.
  • ROI region of interest
  • the controller 110 may define the ROI by the reference line in the image that selects the pixel data to be analyzed as shown in Figure 3.
  • the controller 110 may set an area having a certain shape as the ROI.
  • a rectangular shape is illustrated as the ROI in Figure 4, the shape of the ROI can be adjusted according to the implementation requirements and includes, but is not limited to, a circle, an eclipse, a triangle, or the like.
  • the controller 110 may execute software that is developed such that the ROI line can be specified either interactively or program- matically.
  • the ROI consists of image pixels having values that vary, e.g., from 0 to 255, according to the brightness of the image.
  • the controller 110 may detect the edge locations of the meniscus of the ink, where the image pixel values cross the threshold value.
  • a user may determine the threshold value by operating the threshold controller 306 of the application program display 300.
  • the controller 110 obtains the meniscus motion graph from the processed images of the ink.
  • the controller 110 collects the locations on the reference line that are detected through the edge detection algorithm by varying the delay between the first and second trigger signal pulses 118 and 120, and links each point to generate the meniscus motion graph as shown in the graph viewer 310 of Figure 3.
  • the graph viewer 310 displays a graph showing the meniscus motion of the ink as the delay changes according to the setting by a user through the operational interface 314.
  • FIG. 12 one embodiment of a method for diagnosing an inkjet printing device is illustrated. Initially at operation 1202, the controller controls the trigger signal pulse generator 114 to apply the first control signal pulse 118 to the print head 102 of a printing device in a similar fashion as described with reference to operation 1102 of Figure 11.
  • the controller 110 obtains images of the meniscus motion of the ink that are taken by illuminating the ink with the lighting unit 104 driven by the second trigger signal pulse 120. That is, under the control or instruction of the controller 110, the trigger signal pulse generator 114 in the print head driver 112 applies the second trigger signal pulse 120 to the lighting unit driver 106 for driving the lighting unit 104 in a similar fashion as described with reference to operation 1104 of Figure 11.
  • the image capturing unit 108 captures images of the meniscus motion of the ink that is contained in the print head 102 and illuminated by the lighting unit 104 that is driven by the second trigger signal pulse 120 in a similar fashion as described with reference to operation 1106 of Figure 11.
  • the controller 110 performs image processing on the images obtained by the image capturing unit 108 in a similar fashion as described with reference to operation 1108 of Figure 11. In this way, the controller 110 may obtain the meniscus motion graph shown in Figure 5 and display the meniscus motion graph on the graph viewer 310 of the application program display 300 as shown in Figure 3.
  • the controller 110 may analyze the graph of the meniscus motion to obtain the characteristics of the meniscus motion, such as damping ratio, peak amplitude, and the like.
  • the controller 110 may estimate the characteristics of the meniscus motion of the ink. For example, the controller 110 may interpret the meniscus motion as follows: (i) a larger peak amplitude to mean a stronger pressure (i.e., a larger voltage) for jetting the ink (i.e., easy jetting); (ii) a higher damping ratio (i.e., larger
  • the controller 110 outputs diagnosis information on the status of the print head and the material characteristics of the ink based on the analyzed results obtained at operation 1208.
  • the controller 110 may detect abnormal jetting conditions, such as bubbles trapped in the print head, by observing the peak amplitude, and measure the ink material status, such as viscosity, speed of sound, and the like, by observing the damping ratio and the period. For example, when the controller 110 determines that the peak amplitude is small, the controller 100 may display an indication that the pressure for jetting the ink needs to be increased. Further, when the controller 110 determines that the damping ratio is high, the controller 100 may display an indication that the viscosity of the ink needs to be reduced.
  • the controller 110 may obtain the meniscus motion graph in a similar fashion as described with reference to operations 1202 to 1206 of Figure 12.
  • the controller 110 delivers a control signal to cause the print head driver 112 to generate the basic waveforms for driving the print head 102, which have negative and positive signs as shown in Figures 6 and 7, respectively.
  • the basic waveforms may have falling and rising times having predetermined values, e.g., 2-10 ⁇ sec.
  • the controller 110 may measure the meniscus motions to display graphs of the meniscus motions for the two basic waveforms, as shown in Figures 6 and 7.
  • the waveform generator 116 in the print head driver 112 may generate a basic waveform having a large dwell time, e.g., more than 30 ⁇ sec.
  • the controller 110 may design a waveform based on the meniscus motion graph obtained through operations 1302 to 1306.
  • the controller 110 may use the measured meniscus motion for determining the voltage amplitude and the dwell time of the waveform.
  • the controller 110 measures the characteristics of the meniscus motion of the ink, such as the period, peak amplitude, and damping ratio, and uses the characteristics to modify the basic waveforms. For example, the controller 110 may determine the dwell time of the waveform to be the period of the meniscus motion, and determine the voltage amplitude of the waveform according to the peak amplitude of the meniscus motion.
  • the controller 110 combines the basic waveforms based on the status of the print head 102 and the material status of the ink. From the measured meniscus motion, the controller 110 determines whether the peak amplitude of the meniscus motion is sufficient to initiate the jetting of ink from the print head 102 that is derived by the basic waveforms. If the controller 110 determines that the meniscus motion is sufficient, the controller 110 triggers the waveform generator 116 to generate the basic waveform shown in Figure 6 and after the delay T, triggers the waveform generator 116 to generate the basic waveform shown in Figure 7.
  • the waveform generator 116 may generate a waveform that has dwell time T (i.e., equal to the period of the meniscus motion) and cancels out the meniscus vibration after jetting ink. If the controller 110 determines that the meniscus motion is not sufficient, the controller 110 triggers the waveform generator 116 to generate the basic waveform shown in Figure 6 with a sign inversion and after the delay T/2, triggers the waveform generator 116 to generate the basic waveform shown in Figure 7 with a sign inversion.
  • the sign inversion can be implemented by applying a voltage opposite to the voltage applied to generate the basic waveforms.
  • the waveform generator 116 may generate a waveform that has a dwell time T/2 (i.e., equal to half of the period of the meniscus motion) and has an amplified amplitude sufficient to jet ink.
  • the waveform generator 116 generates a waveform having the period of T and then combines the two waveforms with the periods T/2 and T, respectively, to generate a combined waveform as shown in Figure 10.
  • the waveform generator 116 may generate a waveform that has amplified amplitude sufficient to jet ink and cancels out the meniscus vibration after jetting ink.
  • a method implemented in software may include computer code to perform the operations of the method.
  • This computer code may be stored in a machine-readable medium, such as a processor- readable medium or a computer program product, or transmitted as a computer data signal embodied in a carrier wave, or a signal modulated by a carrier, over a transmission medium or communication link.
  • the machine-readable medium or processor-readable medium may include any medium capable of storing or transferring information in a form readable and executable by a machine (e.g., by a processor, a computer, etc.).

Landscapes

  • Ink Jet (AREA)

Abstract

L'invention vise à proposer des techniques pour mesurer un mouvement d'encre. Dans un mode de réalisation, un appareil comprend un générateur d'impulsions, un générateur de forme d'onde, une unité d'éclairage, une unité de capture d'images et un dispositif de commande. Le générateur d'impulsions est configuré de façon à générer une première impulsion de signal de déclenchement et une deuxième impulsion de signal de déclenchement en fonction du signal de commande, une deuxième impulsion de signal de commande étant générée après un retard variable par rapport à la première impulsion de signal de déclenchement. Le générateur de forme d'ondes est configuré de façon à générer une forme d'onde pour commander un dispositif d'impression en fonction de la première impulsion de signal de déclenchement. L'unité d'éclairage est configurée de façon à éclairer de l'encre dans le dispositif d'impression en fonction de la deuxième impulsion de signal de déclenchement. L'unité de capture d'images est configurée de façon à capturer une pluralité d'images de l'encre, chaque image étant capturée à un instant différent avec un retard différent entre les premier et deuxième signaux d'impulsion de déclenchement.
PCT/KR2008/002119 2008-04-15 2008-04-15 Système d'impression WO2009128572A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
KR1020107022955A KR101207888B1 (ko) 2008-04-15 2008-04-15 잉크 모션 측정 장치 및 방법
PCT/KR2008/002119 WO2009128572A1 (fr) 2008-04-15 2008-04-15 Système d'impression

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/KR2008/002119 WO2009128572A1 (fr) 2008-04-15 2008-04-15 Système d'impression

Publications (1)

Publication Number Publication Date
WO2009128572A1 true WO2009128572A1 (fr) 2009-10-22

Family

ID=41199251

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2008/002119 WO2009128572A1 (fr) 2008-04-15 2008-04-15 Système d'impression

Country Status (2)

Country Link
KR (1) KR101207888B1 (fr)
WO (1) WO2009128572A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016018357A1 (fr) * 2014-07-31 2016-02-04 Hewlett-Packard Development Company, L. P. Entretien d'une tête d'impression d'une imprimante
US20170096002A1 (en) * 2015-10-01 2017-04-06 Océ Printing Systems GmbH & Co. KG Method to reduce an increased viscosity in an ink print head of an ink printer
JP2017142208A (ja) * 2016-02-12 2017-08-17 セイコーインスツル株式会社 液滴吐出装置、及び液滴吐出検査方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003028696A (ja) * 2001-07-17 2003-01-29 Canon Inc 液滴量測定方法、液滴量測定装置及びそれを備えたインクジェットプリンタの製造システム
JP2006142808A (ja) * 2004-10-05 2006-06-08 Applied Materials Inc インクジェットの液滴可視化
JP2007152853A (ja) * 2005-12-07 2007-06-21 Canon Inc 記録装置及びレジストレーション調整方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4117153B2 (ja) 2001-10-05 2008-07-16 松下電器産業株式会社 インクジェットヘッド及びインクジェット式記録装置
JP2004160903A (ja) 2002-11-15 2004-06-10 Ricoh Co Ltd ヘッド駆動制御装置及び画像記録装置
JP2007216461A (ja) * 2006-02-15 2007-08-30 Konica Minolta Holdings Inc 液体吐出装置及び液体吐出方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003028696A (ja) * 2001-07-17 2003-01-29 Canon Inc 液滴量測定方法、液滴量測定装置及びそれを備えたインクジェットプリンタの製造システム
JP2006142808A (ja) * 2004-10-05 2006-06-08 Applied Materials Inc インクジェットの液滴可視化
JP2007152853A (ja) * 2005-12-07 2007-06-21 Canon Inc 記録装置及びレジストレーション調整方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
KYE-SI KWON.: "Speed measurement of ink droplet by using edge detection techniques.", MEASUREMENT., 1 April 2008 (2008-04-01), Retrieved from the Internet <URL:http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V42-4S62RJK-3&_user=981501&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000048939&_version=1&_urlVersion=0&_userid=981501_&md5=9830fdab03ba0cb2a123f97132e47fc5> [retrieved on 20081118] *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016018357A1 (fr) * 2014-07-31 2016-02-04 Hewlett-Packard Development Company, L. P. Entretien d'une tête d'impression d'une imprimante
US20170096002A1 (en) * 2015-10-01 2017-04-06 Océ Printing Systems GmbH & Co. KG Method to reduce an increased viscosity in an ink print head of an ink printer
US10059095B2 (en) * 2015-10-01 2018-08-28 Océ Printing Systems GmbH & Co. KG Method to reduce an increased viscosity in an ink print head of an ink printer
JP2017142208A (ja) * 2016-02-12 2017-08-17 セイコーインスツル株式会社 液滴吐出装置、及び液滴吐出検査方法

Also Published As

Publication number Publication date
KR101207888B1 (ko) 2012-12-05
KR20100136506A (ko) 2010-12-28

Similar Documents

Publication Publication Date Title
CN113211979B (zh) 一种可提高印刷精度的墨水压电控制***及优化方法
KR100901075B1 (ko) 잉크젯 프린터 헤드의 제팅특성 평가 장치 및 방법
CN105939858B (zh) 评估打印喷嘴状况
TW200621512A (en) Liquid drop ejector, method for manufacturing electrooptical device, electrooptical device and electronic apparatus
Kwon Speed measurement of ink droplet by using edge detection techniques
JP6384262B2 (ja) 印刷装置、方法およびプログラム
Kwon et al. Investigation of pulse voltage shape effects on electrohydrodynamic jets using a vision measurement technique
EP2842752A1 (fr) Détection de santé d&#39;une tête d&#39;impression à jet d&#39;encre
WO2009128572A1 (fr) Système d&#39;impression
US8087294B2 (en) Discharge inspection mechanism, recording device, discharge inspection method, and discharge inspection program
CN112373207A (zh) 喷墨测试方法、装置以及终端设备
JP2017177626A (ja) ヘッドユニットの製造方法
CN113324580B (zh) 基于感应电流和机器视觉的静电微滴喷射状态检测方法
Kwon Vision monitoring
KR101095369B1 (ko) 잉크방울의 메니스커스 측정 방법
KR101095366B1 (ko) 잉크방울의 거동 분석 시스템 및 이를 이용한 잉크방울 거동 분석 방법
JP7069751B2 (ja) 印刷装置
JP2022173205A (ja) 塗布装置、塗布方法及びプログラム
KR101151661B1 (ko) 고속 카메라를 이용한 이미지 분석 방법
CN208827139U (zh) 一种喷墨打印微液滴驱动及观测***
JP7135687B2 (ja) ハンディプリンタ、塗布システム、塗布方法及びプログラム
KR101178419B1 (ko) 잉크 방울의 거동 분석 방법
US20230415478A1 (en) Method Of Determining Ejection State
JP2010036388A (ja) 液滴量測定方法およびこれを搭載した液滴吐出システム
KR100927696B1 (ko) 잉크젯프린터기에 있어서 잉크방울의 속도측정방법

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 08741364

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 20107022955

Country of ref document: KR

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 08741364

Country of ref document: EP

Kind code of ref document: A1