JP2013158656A - Inkjet printer and method for controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem of stripe-shaped color unevenness caused by the relation between a bank interval and a nozzle interval without needing the replacement or the angle adjustment of an inkjet head.SOLUTION: An inkjet printer moves a substrate to a print scanning direction while supplying ink to each bank by discharging the ink from each nozzle of inkjet nozzles 2 each having a plurality of nozzles 2a, 2b to the substrate 1 disposed with the banks 1a, 1b having an interval corresponding to the pixel interval of a display panel. When the bank interval of the print scanning direction is Lpx, the nozzle interval of the print scanning direction is Lnx, the nozzle interval of a direction orthogonal to the print scanning direction is Lny, and print resolution is Rx, Lpx, Lnx, Lny and Rx, satisfying each expression of Lpx=k×Rx, n×Lnx=m×Rx, Lny×n<λv (λv is a human recognizable spatial period), are determined, and the inkjet printer performs printing by use of the determined values thereof.

Description

  The present invention relates to an inkjet printing apparatus and a control method thereof. For example, the present invention relates to a light emitting layer of a display panel for a display device such as an organic EL (Electro Luminescence), an ink jet printing apparatus used for other coating processes, and a control method thereof.

  An ink jet printing apparatus includes an ink jet head having a plurality of nozzles, and applies ink to a print target by ejecting ink from the nozzle while controlling the positional relationship between the nozzle of the ink jet head and the print target.

  As an inkjet head used for printing, in recent years, an inkjet head in which nozzles are two-dimensionally arranged at a high density in order to perform printing at a high resolution has been used.

  FIG. 7 shows a schematic diagram of an ink jet head in which the nozzle array is arranged in an inclined manner in accordance with the printing object by arranging the nozzle row in an inclined manner when the printing object is narrower than the nozzles.

  In FIG. 7, reference numeral 12 denotes an ink jet head. The ink jet head 12 has eight nozzle holes 12 a to 12 h for ejecting ink arranged in a line at equal intervals. In FIG. 7, banks 11a to 11e provided for forming pixels of the substrate 11 for display panel are shown as examples of print targets.

  As shown in FIG. 7, in the inkjet head 12 in which the nozzle row is inclined with respect to the movement direction of the printing target, the nozzles are arbitrarily set in the direction y orthogonal to the movement direction x of the printing target by adjusting the inclination θ. It is possible to arrange them at intervals. That is, the interval Lny between the nozzle holes 12a to 12h can be arbitrarily set in the range of 0 ≦ Lny ≦ L.

  In the printing industry, since DPI (dots per inch) is used as a unit indicating resolution, the nozzle arrangement is generally designed in units of inches along the DPI.

  On the other hand, since the display industry is designed based on the SI unit system, the display pixel spacing is designed in μm units, and the pixel spacing is generally in the order of μm in the range of 250 to 350 μm. It is a numerical value.

  When printing using an inkjet head with an inch-type nozzle spacing on a display panel with a pixel spacing of μm units, the printing position shift due to the difference in the unit system of the pixel spacing and nozzle spacing of the display panel is periodic. This appears as striped unevenness.

  In the following, in order to simplify the description, the mechanism of occurrence of the striped unevenness will be described separately for the case of printing with one nozzle and the case of printing with two nozzles arranged on the inkjet head.

  FIG. 8 shows a schematic side view for explaining the printing timing of the printing method using one nozzle. The same reference numerals are used for the same components as in FIG.

  First, the components in FIG. 8 will be described.

  Reference numeral 11 denotes a display panel substrate, which is provided with recesses 11a to 11c called banks for forming pixels. The banks 11a to 11c are arranged on the substrate 11 at equal intervals so that the interval in the print scanning direction x is Lpx.

  Reference numeral 12 denotes an inkjet head, which ejects ink 13 from the nozzle hole 12a. The ejection of the ink 13 from the nozzle hole 12a is performed by a print timing signal 15 generated by the ink jet controller 14.

  Next, the operation when printing with one nozzle will be described.

  At the time of printing, the substrate 11 is moved relative to the inkjet head 12 at a speed Vx, and the ink 13 is ejected from the nozzle holes 12a by the print timing signal 15 generated by the inkjet controller 14, and each substrate 11 Printing is performed on the banks 11a to 11c. At that time, in order to supply the ink 13 to the center of each of the banks 11a to 11c, the ink 13 may be ejected at the timing when each of the banks 11a to 11c of the substrate 11 moves directly below the nozzle hole 12a. Printing is performed at intervals at which Tp satisfies Tp = Lpx / Vx.

  Next, FIG. 9 shows a schematic side view for explaining the printing timing of the printing method using two nozzles. The same reference numerals are used for the same components as in FIG.

  First, the components in FIG. 9 will be described.

  Reference numeral 11 denotes a display panel substrate, which is provided with recesses 11a to 11c called banks for forming pixels. The banks 11a to 11c are arranged on the substrate 11 at equal intervals so that the interval in the print scanning direction x is Lpx.

  Reference numeral 12 denotes an ink-jet head, which is arranged obliquely so that the interval between the nozzle holes 12a and 12b in the print scanning direction x is Lnx as shown in the top view of FIG. 9, and from each nozzle hole 12a and 12b. Ink 13 is discharged. The ejection of the ink 13 from the nozzle holes 12a and 12b is performed by a print timing signal 15 generated by the inkjet controller 14.

  Next, the operation when printing with two nozzles will be described with reference to FIG.

FIG. 10 is a schematic diagram for explaining ink landing position deviation due to printing timing deviation.
(A) is a diagram in which the ink 13 is ejected at the timing when the bank 11a is moved directly below the nozzle hole 12a, and (b) is the ink 13 that is ejected at the timing at which the bank 11a is moved directly below the nozzle hole 12b. (C) is a diagram in which the ink 13 is ejected at the timing when the bank 11b moves directly below the nozzle hole 12a.

  The print timing signal 15 in FIG. 10 indicates the timing at which the ink 13 is ejected from the nozzle holes 12a according to the banks 11a to 11c of the substrate 11 as in the case of printing with one nozzle shown in FIG. The print timing signal 15a in FIG. 10 indicates the timing at which the ink 13 is ejected from the nozzle holes 12a and 12b to the same bank in accordance with the interval Lnx between the nozzle holes 12a and 12b.

  As can be seen from the print timing signals 15 and 15a in FIG. 10, in the inkjet head having two nozzles arranged at intervals in the print scanning direction, the print timing Tp corresponding to the bank interval Lpx of the substrate 11 and the inkjet head There are printing timings Tn corresponding to 12 nozzle intervals Lnx.

  Here, the printing timings Tp and Tn are generated by dividing the pulses generated by the pulse generator, and can generate arbitrary timings. However, in order to generate both the print timings Tp and Tn, it is not practical because it is necessary to individually generate print timings corresponding to the number of nozzles. Therefore, when the ejection of the ink 13 from the nozzle holes 12a and 12b is operated based on the same timing signal, a relationship of Tp = n × Tn (n is a natural number) does not hold between Tp and Tn. A deviation occurs in the ejection timing of the ink 13 from the second nozzle hole 12b with respect to the bank 11a.

  FIG. 11 is a schematic diagram of a printing result when printing is performed in a state where there is a deviation in printing timing among the plurality of nozzles.

  In FIG. 11, 11a, 11b and 11c are banks, and 13a is an ink landing position. When there is a print timing shift between the plurality of nozzles, the ink landing position 13a gradually shifts in the print scanning direction x due to the print timing shift, and returns to the original position with a constant period ΔY. Note that the double wavy line in FIG. 11 indicates that the description of the bank in the y direction between them is omitted, and FIG. 11 shows that the ink landing position 13a returns to the original for every two or more banks in the y direction. ing.

  Such a periodic positional shift is recognized as striped color unevenness on the completed display panel.

  As a means for suppressing such striped unevenness, a method of arranging the nozzle interval Lnx in the print scanning direction of the inkjet head so that Tp = n × Tn is established in advance is conceivable (for example, refer to Patent Document 1).

  FIG. 12 is a schematic diagram showing the positional relationship between the inkjet head and the bank for explaining the method for suppressing striped unevenness in the film forming apparatus described in Patent Document 1. As shown in FIG. The same reference numerals are used for the same components as in FIG.

  In the inkjet head 12, eight nozzle holes 12a to 12h are arranged in a line at equal intervals.

  In FIG. 12, while the substrate moves in the x direction, ink is ejected from the nozzle holes 12a to 12h of the inkjet head 12 to the banks 11a to 11d on the substrate, and the bank 11e moves immediately below the nozzle holes 12a. The state that has been done.

  In the film forming apparatus shown in FIG. 12, the nozzle interval L of the inkjet head 12 and the rotation angle θ of the inkjet head 12 are determined and arranged so that the relationship of Lpx = n × Lnx (n is a natural number) is established, The print timing is set to Tp = n × Tn, and striped unevenness due to the printing position deviation is eliminated. FIG. 12 shows an example of n = 2.

JP 2004-267874 A

  However, in the configuration of the film forming apparatus of Patent Document 1, when printing another substrate with a different bank interval, the inkjet head must be replaced or the mounting angle must be adjusted each time, resulting in increased manufacturing time and production. Efficiency is reduced.

  In order to replace the ink jet head or adjust the mounting angle, it takes about 1 hour to change the product type, and when performing multi-product production, the time loss is too great.

  In recent years, in order to perform high-quality printing at high speed, it is often the case that a plurality of nozzle arrays are arranged side by side. In such a configuration, the nozzles are densely arranged, More time is required to adjust the mounting angle.

  Furthermore, since the nozzle interval Lnx in the printing scanning direction and the nozzle interval Lny in the direction orthogonal to the printing scanning direction change by exchanging the inkjet head and adjusting the mounting angle, the printing data can be changed accordingly. It becomes complicated, such as remaking it again.

  As shown in FIG. 11, even if the amount of positional deviation in the print scanning direction x is as small as about 10 μm, the periodic interval ΔY of the periodic deviation in the direction y orthogonal to the printing scanning direction is 80 μm, which is a human recognizable spatial frequency. If it becomes above, it will be recognized as striped color unevenness on the completed panel. Therefore, it is necessary to strictly adjust the mounting angle of the ink jet head for printing another substrate having a different bank interval.

  However, if the repetition interval ΔY of the deviation in the direction y perpendicular to the print scanning direction is made smaller than 80 μm, which is a human-recognizable spatial frequency, the striped color unevenness is not recognized on the completed display panel. The present invention pays attention to this point, and by setting the repetition interval ΔY within a range that is not determined as striped color unevenness on the completed display panel, even if the substrate has a different bank interval, the inkjet head can be replaced or angled. Adjustment is unnecessary.

  In consideration of the above problems, the present invention does not require replacement of an inkjet head or angle adjustment, and can eliminate striped color unevenness caused by the relationship between bank spacing and nozzle spacing, and a control method therefor The purpose is to provide.

In order to solve the above-described problem, the first aspect of the present invention provides:
Ink is supplied from each nozzle of an inkjet head having a plurality of nozzles according to a predetermined printing timing to a substrate on which a bank having an interval corresponding to the pixel interval is arranged, which is used for a display panel having a fixed pixel interval. A method of controlling an inkjet printing apparatus, wherein the substrate is moved relative to the inkjet head in a printing scan direction relative to the inkjet head while supplying ink to each bank by discharging,
Lpx is a bank interval in the print scanning direction of the substrate, Lnx is a nozzle interval in the print scanning direction of the inkjet head, Lny is a nozzle interval in a direction orthogonal to the printing scan direction of the inkjet head, and intermittent of the substrate. Control method for an ink jet printing apparatus that determines Lpx, Lnx, Lny, and Rx so that Equation 1 is satisfied, and uses the determined values to print on the substrate, where Rx is the print resolution that is the target movement amount It is.

The second aspect of the present invention
A plurality of display panels each having a fixed pixel interval, and at least a bank of intervals corresponding to each pixel interval is used for the plurality of display panels having different pixel intervals between a pair of display panels. Ink is supplied to each bank by ejecting ink according to a predetermined printing timing from each nozzle of an inkjet head having a plurality of nozzles to a plurality of substrates (u; u is an integer of 2 or more) While, the control method of the ink jet printing apparatus for moving each of the substrates relative to the ink jet head in a printing scan direction relatively and intermittently,
Lpx (i) is the bank interval in the print scanning direction for each substrate i (i = 1, 2,..., U), Lnx is the nozzle interval in the print scanning direction of the inkjet head, and the Assuming that the nozzle interval in the direction orthogonal to the print scanning direction is Lny and the print resolution, which is the amount of intermittent movement for each substrate i, is Rx (i), Equation 2 is established after fixing Lnx and Lny. And a method of controlling an ink jet printing apparatus that determines Lpx (i) and Rx (i) for each of the substrates i, and prints on each of the substrates i using the determined values.

The third aspect of the present invention
The Lnx is a method for controlling the ink jet printing apparatus according to the first or second aspect of the present invention, wherein the Lnx is a value that becomes a one-digit circulation decimal.

The fourth aspect of the present invention is
Ink is supplied from each nozzle of an inkjet head having a plurality of nozzles according to a predetermined printing timing to a substrate on which a bank having an interval corresponding to the pixel interval is arranged, which is used for a display panel having a fixed pixel interval. An ink jet printing apparatus that moves the substrate relative to the ink jet head in a print scanning direction relatively and intermittently while supplying ink to each bank by discharging,
Lpx is a bank interval in the print scanning direction of the substrate, Lnx is a nozzle interval in the print scanning direction of the inkjet head, Lny is a nozzle interval in a direction orthogonal to the printing scan direction of the inkjet head, and intermittent of the substrate. Inkjet printing provided with a control unit that controls printing on the substrate using the values of Lpx, Lnx, Lny and Rx determined so that Equation 1 is satisfied when the printing resolution that is the amount of movement is Rx Device.

The fifth aspect of the present invention provides
A plurality of display panels each having a fixed pixel interval, and at least a bank of intervals corresponding to each pixel interval is used for the plurality of display panels having different pixel intervals between a pair of display panels. Ink is supplied to each bank by ejecting ink according to a predetermined printing timing from each nozzle of an inkjet head having a plurality of nozzles to a plurality of substrates (u; u is an integer of 2 or more) An inkjet printing apparatus that moves each of the substrates relative to the inkjet head in a print scanning direction relatively and intermittently,
Lpx (i) is the bank interval in the print scanning direction for each substrate i (i = 1, 2,..., U), Lnx is the nozzle interval in the print scanning direction of the inkjet head, and the Assuming that the nozzle interval in the direction orthogonal to the print scanning direction is Lny and the print resolution, which is the amount of intermittent movement for each substrate i, is Rx (i), Equation 2 is established after fixing Lnx and Lny. The inkjet printing apparatus includes a control unit that controls printing on each of the substrates i using the values of Lpx (i) and Rx (i) determined for each of the substrates i.

The sixth aspect of the present invention provides
The Lnx is the inkjet printing apparatus according to the fourth or fifth aspect of the present invention, which is a value that is a circulation decimal with one digit in the circulation node.

  According to the present invention, it is possible to provide an inkjet printing apparatus and a control method therefor that can eliminate striped color unevenness caused by the relationship between the bank interval and the nozzle interval without requiring replacement of the inkjet head or angle adjustment.

1 is a block diagram of an inkjet printing apparatus according to Embodiment 1 of the present invention. 1 is a schematic diagram showing an ink jet head according to Embodiment 1 of the present invention, in which nozzle rows are inclined. The figure explaining the ink ejection timing in the 1st Example of Embodiment 1 of this invention, and the ink landing position to each bank The figure explaining the ink discharge timing in the 2nd Example of Embodiment 1 of this invention, and the ink landing position to each bank The figure explaining the ink discharge timing in the 3rd Example of Embodiment 1 of this invention, and the ink landing position to each bank (A) The figure which shows the landing state of the ink in the bank in the 1st Example of Embodiment 1 of this invention, (b) In the bank in the 2nd Example of Embodiment 1 of this invention. The figure which shows the landing state of an ink, (c) The figure which shows the landing state of the ink in a bank in the 3rd Example of Embodiment 1 of this invention, (d) The landing of the ink in a bank in a prior art example Diagram showing state Schematic diagram showing a conventional inkjet head in which the nozzle row is inclined with respect to the moving direction of the printing target Schematic side view for explaining the printing timing of the printing method by one nozzle Side schematic diagram for explaining the printing timing of the printing method by two nozzles Schematic diagram for explaining ink landing position deviation due to deviation of printing timing when printing with two conventional nozzles Schematic diagram showing the printing results when printing is performed in a state where there is a deviation in the printing timing between multiple nozzles The schematic diagram which shows the positional relationship of an inkjet head and a bank for demonstrating the suppression method of the striped nonuniformity in the film-forming apparatus of patent document 1

  First, the main points of the present invention will be described.

  FIG. 2 is a schematic diagram of an ink jet head in which the nozzle row of the present invention is disposed at an angle.

  In FIG. 2, reference numeral 2 denotes an inkjet head. In the inkjet head 2, eight nozzle holes 2 a to 2 h for ejecting ink are arranged in a line at equal intervals. In FIG. 2, printing is performed on banks 1a to 1e provided for forming pixels of the substrate 1 for the display panel as a printing target. The banks 1a to 1e are provided on the substrate 1 at intervals corresponding to a certain pixel interval of the display panel.

  As a result of verification to achieve the object of the present application, with reference to FIG. 2, for a substrate in which the bank interval Lpx in the print scanning direction of the display panel is a natural number, printing is performed with a nozzle interval Lnx that satisfies the following relationship: It was discovered that striped color unevenness can be eliminated by setting the resolution Rx.

  First, the nozzle interval Lnx in the print scanning direction x of the inkjet head is arranged at a value that is a circulation decimal with one digit of the circulation node when expressed in the same unit system as the bank interval Lpx. Next, a value that is a natural number is selected from among values obtained by dividing the bank interval Lpx in the print scanning direction x of the display panel by a natural number for the print resolution Rx in the print scanning direction x. At this time, in order for the print resolution Rx to be a natural number, the bank interval Lpx needs to be divisible by the natural number, so the bank interval Lpx is restricted to a value other than a prime number.

  The inventor of the present application derived a relationship of Formula 2 as a result of obtaining a generalized relationship of the verification result.

  Satisfying the relationship of each equation of Formula 2 for all (u: i = 1 to u) repetition intervals Lpx (i) required for all the printing materials to be printed by the printing press One Lnx (nozzle interval) and u sets of k (i), Rx (i), k (i), n (i), m (i) are obtained, and the nozzles are arranged at the Lnx nozzle interval, Printing is performed at the printing resolution Rx (i) obtained previously with respect to the repetition interval Lpx (i) of the u sets of prints.

  In Equation 2, i is the classification number of the printing medium, and the total number of printing mediums is u. Lpx (i) is a bank interval in the print scanning direction x, which is the direction of movement with respect to the nozzles, and is a repetition interval required for the substrate i. Rx (i) is the print resolution in the print scanning direction x, and is the minimum nozzle discharge interval of the printing machine used for the printing object i. Lnx is an interval in the printing scanning direction x between adjacent nozzles of the printing press, and is common to all the printing objects i. k (i), n (i), and m (i) are arbitrary integers for each printing medium i. λv is a human-recognizable spatial period.

  By printing at the bank interval Lpx (i) on the printing medium i with the nozzle interval Lnx and the printing resolution Rx (i) on the printing medium i satisfying the above conditions, all the printing mediums within the bank It is possible to perform printing in which the ejection traces applied to the surface are not visible as striped unevenness.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention having the above contents as the main points will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram of an ink jet printing apparatus according to Embodiment 1 of the present invention.

  On the substrate 1 to be printed, banks 1a, 1b,... Are arranged at an interval Lpx with respect to the print scanning direction x.

  A plurality of inkjet heads 2 are arranged in the y direction orthogonal to the printing scanning direction x. In each inkjet head 2, nozzle holes 2a, 2b,... Are arranged at an interval Lnx with respect to the printing operation direction x.

  The substrate 1 is moved relative to the inkjet head 2 by the moving stage 3.

  The inkjet controller 4 outputs a nozzle drive signal to each nozzle of the inkjet head 2. The ink jet controller 4 includes a position detector 4a, an ejection timing generator 4b, a drive signal generator 4c, a print data generator 4d, and a drive signal selector 4e. Hereinafter, each block of the inkjet controller 4 will be described.

  The ink jet controller 4 corresponds to an example of a control unit of the present invention.

  The position detector 4a converts the position information of the moving stage 3 on which the substrate 1 to be printed is placed into a pulse signal, and generates a position information pulse signal.

  The discharge timing generator 4b divides the position information pulse signal output from the position detector 4a based on the preset print resolution Rx, and discharges that specify the generation timing of the voltage waveform that drives the nozzles of the inkjet head. Generate and output a timing signal.

  The drive signal generator 4c outputs a drive waveform signal for causing ink to be ejected from the nozzles of the inkjet head 2 based on the ejection timing signal from the ejection timing generator 4b.

  The print data generator 4d sets the discharge ON / OFF state for each pixel corresponding to the print resolution Rx and the nozzle interval of the inkjet head 2 so that a preset print image can be printed on the substrate 1 without any unevenness. Convert to the determined print bitmap data.

  The drive signal selector 4e turns on / off the drive waveform signal from the drive signal generator 4c for each nozzle in accordance with the discharge on / off instruction for each pixel of the print bitmap data sent from the print data generator 4d. Ink ejection is controlled by outputting a nozzle-linked ejection control bus signal to the inkjet head 2.

  Next, the operation of the ink jet printing apparatus according to the first embodiment will be described.

  A print resolution Rx and a print image to be printed on the substrate 1 are prepared in advance, and set in the ejection timing generator 4b and the print data generator 4d, respectively.

  Next, the substrate 1 is placed on the moving stage 3. When the moving stage 3 is moved with respect to the inkjet head 2, position information having position information in the phase difference is generated in time series. In the ink jet printing apparatus according to the first embodiment, position information obtained from the phase difference between the A phase and the B phase of the pulse signal of the position detector 4a is used.

  The moving stage 3 moves the substrate 1 in the print scanning direction by continuously performing intermittent movement in the print scanning direction. Position information is generated for each intermittent movement at this time. In the first embodiment, since the substrate 1 is moved with respect to the inkjet head 2, the intermittent movement amount of the substrate 1 at this time becomes the printing resolution Rx.

  When it is necessary to shorten the printing time, the stop time during intermittent movement in the printing scanning direction is set to 0, and the inkjet head is based on the positional information of the moving stage 3 that is continuously moving in the printing direction. When ink is ejected from each of the two nozzles, printing can be performed in a shorter time.

  The position information is input to the position detector 4a, converted into position information pulses, and input to the ejection timing generator 4b. The discharge timing generator 4b divides the input position information based on a preset print resolution Rx, and generates a discharge timing signal as a discharge signal for each print pixel.

  The ejection timing signal is input to the drive signal generator 4c, and the drive signal generator 4c outputs a drive waveform signal for ejecting ink from the nozzles of the inkjet head based on the ejection timing signal.

  On the other hand, in the print data generator 4d, ejection is turned on / off for each pixel corresponding to the print resolution Rx and the nozzle interval of the inkjet head 2 so that a preset print image can be printed on the substrate 1 without unevenness. The state is converted into the determined printing bitmap data, and the nozzles to be used are simultaneously output as nozzle-linked discharge control bus signals.

  The drive signal selector 4e turns on / off the drive waveform signal from the drive signal generator 4c for each nozzle in accordance with the discharge on / off instruction for each nozzle of the nozzle-linked discharge control bus signal sent from the print data generator 4d. By turning off, ink ejection is controlled.

  The timing at which ink is ejected from each nozzle is an example of the predetermined printing timing of the present invention.

  When the moving stage 3 passes under the inkjet head 2 at the speed Vx, the above operation is repeatedly executed. When the ink is ejected on the substrate 1 based on the printed image at the printing resolution Rx, and completely passes. All the ejections based on the printed image have landed on the substrate 1.

  Next, a printing example, which is a feature of the present invention, is a print in which the ejection traces applied in the bank are not visible as striped unevenness.

  In this printing example, with respect to three types of printing bodies (substrate 1), the respective bank intervals Lpx (i) are Lpx (1) = 316 μm, Lpx (2) = 256 μm, and Lpx (3) = 317.5 μm ( 80 DPI). Then, three print resolutions Rx (i) satisfying the condition of Equation 2 and a unique nozzle interval Lnx are obtained.

  For example, as shown in Table 1, Rx, k, m, and n are selected for each Lpx. Regarding selection, n is made as small as possible. The reason for this will be described later.

  From the above, the Rx in each Lpx and the common Lnx were obtained.

(First embodiment)
First, a first embodiment for printing with a nozzle resolution of 169.33333 μm at a printing resolution of 4 μm for a bank spacing of 316 μm with i = 1 will be described with reference to FIG.

  FIG. 3 is a diagram for explaining the ink ejection timing and the ink landing position on each bank in the first embodiment (when i = 1).

  The inkjet head 2 is provided with six nozzle holes in which the first nozzle hole is 2a, the second nozzle hole is 2b, and the sixth nozzle hole is 2f, and each of the nozzle holes 2a to 2f is provided. Are arranged so that the interval in the print scanning direction is 169.33333 μm.

  The discharge trigger is an enumeration of the discharge trigger pulses of each nozzle in chronological order. When the application bank of the substrate 1 arrives just below the first nozzle hole 2a, the discharge trigger pulse 0 is synchronized at time t0, and printing is performed. At time t1 after a passage time corresponding to a resolution of 4 μm, the next ejection trigger pulse 1 is generated. Since the time when the bank arrives directly below the second nozzle hole 2b is 169.33333 / 4 = 42.33333, it is the time obtained by adding 1/3 pulse (1.33333 μm) to the ejection pulse 42 at time t42. The bank arrival time immediately below the third nozzle hole 2c is 169.33333 × 2/4 = 84.66666, which is the time obtained by subtracting 1/3 pulse (1.33333 μm) from the ejection pulse 85 at time t85. The bank arrival time just below the fourth nozzle hole 2d was 169.33333 × 3/4 = 127, which is exactly time t127, and was completed here. Similarly, the bank arrival time immediately below the fifth nozzle hole 2e is a time obtained by adding 1/3 pulse from the time t169, and the bank arrival time immediately below the sixth nozzle hole 2f is the time t212. The time is obtained by subtracting 1/3 pulse from.

  1 a is the first bank on the substrate 1, 1 b is the second bank on the substrate 1, and 1 c is the third bank on the substrate 1. Six dividing lines described in each bank are described at positions that are directly below the six nozzle holes of nozzle holes 2a to 2f when the substrate 1 passes through the ink jet head 2. It is divided by the same number. The interval in the print scanning direction between adjacent banks is 316 μm. The black circle on the bank represents the moment of landing at that position due to ejection from the nozzle, and the white circle represents the trace of landing in the past.

  First, at time t0, the first bank 1a arrives directly below the first nozzle hole 2a. Then, ink is ejected from the first nozzle hole 2a by the ejection pulse 0, and a black circle landing mark is left on the bank 1a. Since the positions of the ejection pulse 0 and the first nozzle hole 2a are synchronized, the landing mark remains in the center of the bank 1a.

  Next, at time t42, the first bank 1a arrives in front of the first nozzle hole 2b by 1/3 pulse. Then, ink is ejected from the second nozzle hole 2b by the ejection pulse 42, leaving a black circle landing mark on the bank 1a. Since the second nozzle hole 2b is ahead by 1/3 pulse with respect to the ejection pulse 42, a landing mark remains at the 1/3 pulse equivalent (1.33333 μm) from the center of the bank 1a.

  At time t79 (corresponding to k), the second bank 1b arrives directly below the first nozzle hole 2a. Then, ink is ejected from the first nozzle hole 2a by the ejection pulse 79, and a black circle landing mark is left on the bank 1b. Since the positions of the ejection pulse 79 and the first nozzle hole 2a are synchronized, the landing mark remains in the center of the bank 1b.

  At time t85, the first bank 1a arrives first by 1/3 pulse from directly below the third nozzle hole 2c. Then, ink is ejected from the third nozzle hole 2c by the ejection pulse 85, and a black circle landing mark is left on the bank 1a. Since the third nozzle hole 2c is 1/3 pulses ahead of the ejection pulse 85, an impact mark remains on the front of the 1/3 pulse (−1.333333 μm) from the center of the bank 1a.

  Similarly, ink is discharged at each time.

  At time t121, ink is ejected from the second nozzle hole 2b at a point equivalent to 1/3 pulse from the center of the second bank 1b.

  At time t127, ink is ejected from the fourth nozzle hole 2d to the center of the first bank 1a.

  At time t158, ink is ejected from the first nozzle hole 2a to the center of the third bank 1c.

  At time t164, ink is ejected from the third nozzle hole 2c before the center of the bank of the second bank 1b by 1/3 pulse.

  At time t169, ink is ejected from the fifth nozzle hole 2e at a point equivalent to 1/3 pulse from the center of the first bank 1a.

  At time t200, ink is ejected from the second nozzle hole 2b ahead of the 1/3 pulse from the center of the third bank 1c.

  At time t206, ink is ejected from the fourth nozzle hole 2d to the center of the second bank 1b.

  At time t212, ink is ejected from the sixth nozzle hole 2f to a position equivalent to 1/3 pulse from the center of the first bank 1a.

  Thus, 6 drops have landed on the first bank 1a, 4 drops have landed on the second bank 1b, and 2 drops have landed on the third bank 1c.

(Second embodiment)
Next, a second embodiment in which printing is performed at a nozzle resolution of 169.33333 μm at a printing resolution of 2 μm with respect to a bank spacing of 256 μm where i = 2 will be described with reference to FIG.

  FIG. 4 is a diagram for explaining the ink ejection timing and the ink landing position on each bank in the second embodiment (when i = 2).

  In this case, as in the first embodiment, landing in the bank proceeds. Since the printing resolution Rx is 2 μm, which is different from 4 μm of the first embodiment, the ejection of ink from the second nozzle hole 2b is ejected by the ejection trigger pulse 85, and the ejection of ink from the third nozzle hole 2c is ejected. The trigger pulse 169, the discharge of ink from the fourth nozzle hole 2d is the discharge trigger pulse 254, the discharge of ink from the fifth nozzle hole 2e is the discharge trigger pulse 339, the discharge of ink from the sixth nozzle hole 2f is The discharge trigger pulse 423 is used.

  Unlike the first embodiment, the ink landing position is different from that of the first embodiment. Ink ejection from the first nozzle hole 2a and the fourth nozzle hole 2d is performed in the center of the bank, and the second nozzle holes 2b and 5 are discharged. Ink ejection from the second nozzle hole 2e is equivalent to 1/3 pulse (−0.66667 μm), and ink ejection from the third nozzle hole 2c and sixth nozzle hole 2f is equivalent to 1/3 pulse ( 0.66667μm).

  In the following, the nozzle numbers and landing positions are listed in order of time when each bank arrives directly under each nozzle hole.

  At time t0, ink is ejected from the first nozzle hole 2a to the center of the first bank 1a.

  At time t85, ink is ejected from the second nozzle hole 2b before the center of the bank of the first bank 1a by 1/3 pulse.

  At time t128, ink is ejected from the first nozzle hole 2a to the center of the second bank 1b.

  At time t169, ink is ejected from the third nozzle hole 2c at a point equivalent to 1/3 pulse from the bank center of the first bank 1a.

  At time t213, ink is ejected from the second nozzle hole 2b before the center of the bank of the second bank 1b by 1/3 pulse.

  At time t254, ink is ejected from the fourth nozzle hole 2d to the center of the first bank 1a.

  At time t256, ink is ejected from the first nozzle hole 2a to the center of the third bank 1c.

  At time t297, ink is ejected from the third nozzle hole 2c at a point equivalent to 1/3 pulse from the center of the second bank 1b.

  At time t339, ink is ejected from the fifth nozzle hole 2e before the center of the first bank 1a by 1/3 pulse.

  At time t341, ink is ejected from the second nozzle hole 2b before the center of the third bank 1c by 1/3 pulse.

  At time t382, ink is ejected from the fourth nozzle hole 2d to the center of the second bank 1b.

  At time t384, ink is ejected from the first nozzle hole 2a to the center of the fourth bank 1d.

  At time t423, ink is ejected from the sixth nozzle hole 2f at a point equivalent to 1/3 pulse from the bank center of the first bank 1a.

  Thus, 6 drops have landed on the first bank 1a, 4 drops on the second bank 1b, 2 drops on the third bank 1c, and 1 drop on the fourth bank 1d. ing.

(Third embodiment)
Finally, a third embodiment of printing with a nozzle resolution of 16.9.33333 μm at a printing resolution of 2.64583333 μm for a bank spacing of i = 3 of 317.5 μm will be described with reference to FIG.

  FIG. 5 is a diagram for explaining the ink ejection timing and the ink landing position on each bank in the third embodiment (when i = 3).

  In this case, as in the first embodiment, landing in the bank proceeds. Since the printing resolution Rx is 2.64583333 μm, which is different from 4 μm of the first embodiment, the ejection of ink from the second nozzle hole 2b is ejection trigger pulse 64, and the ejection of ink from the third nozzle hole 2c is ejection. The discharge of ink from the trigger pulse 128, the fourth nozzle hole 2d is the discharge trigger pulse 192, the discharge of ink from the fifth nozzle hole 2e is the discharge trigger pulse 256, and the discharge of ink from the sixth nozzle hole 2f is The discharge trigger pulse 320 is used.

  Then, unlike the first embodiment, the position of the ink landing deviation is landed on the center of the bank from the first to sixth nozzle holes 2a to 2f.

  In the following, the nozzle numbers and landing positions are listed in order of time when each bank arrives directly under each nozzle hole.

  At time t0, ink is ejected from the first nozzle hole 2a to the center of the first bank 1a.

  At time t64, ink is ejected from the second nozzle hole 2b to the center of the first bank 1a.

  At time t120, ink is ejected from the first nozzle hole 2a to the center of the second bank 1b.

  At time t128, ink is ejected from the third nozzle hole 2c to the center of the first bank 1a.

  At time t184, ink is ejected from the second nozzle hole 2b to the center of the second bank 1b.

  At time t192, ink is ejected from the fourth nozzle hole 2d to the center of the first bank 1a.

  At time t240, ink is ejected from the first nozzle hole 2a to the center of the third bank 1c.

  At time t248, ink is ejected from the third nozzle hole 2c to the center of the second bank 1b.

  At time t256, ink is ejected from the fifth nozzle hole 2e to the center of the first bank 1a.

  At time t304, ink is ejected from the second nozzle hole 2b to the center of the third bank 1c.

  At time t312, ink is ejected from the fourth nozzle hole 2d to the center of the second bank 1b.

  At time t320, ink is ejected from the sixth nozzle hole 2f to the center of the first bank 1a.

  Thus, 6 drops have landed on the first bank 1a, 4 drops have landed on the second bank 1b, and 2 drops have landed on the third bank 1c.

  3, 4, and 5, the first embodiment shown in FIG. 3 is landed alternately from adjacent nozzles at a position of ± 1.333333 μm with reference to the center of the bank. In the second embodiment shown in FIG. 4, the ink is landed alternately from adjacent nozzles at a position of ± 0.666667 μm with reference to the center of the bank. In the third embodiment shown in FIG. 5, all the nozzles land on the center of the bank.

  In FIG. 2, when θ and L are selected so that Lny = 21.1666667 μm (1200 dpi), since Lnx = 169.3333 μm, θ = 82.87498 deg and L = 170.6511223 μm. In this case, in the first embodiment and the second embodiment, the periodic deviation in the y direction occurs at 3 × Lny = 63.5 μm. In the third embodiment, no periodic deviation in the y direction occurs. In general, the period of the spatial frequency that can be recognized by human being is 80 μm or more, which can be applied to a shift having periodicity, which is 63.5 μm in the first example and the second example of the first embodiment. In the case of periodic deviation, the human eyes do not recognize it as striped unevenness.

  Here, the relationship between the integer n and the periodicity will be described. n is the number of repetitions of the number of nozzles (number of positions) in the y direction required until the position of the nozzle hole and the ejection pulse position match.

  This can be confirmed in the above three embodiments. In the first embodiment, n = 3, and the ink ejected from the fourth nozzle hole 2d at the time t127 is landed on the same center of the bank as the ink ejected from the first nozzle hole 2a without any deviation. Similarly, in the second embodiment, the ink ejected from the fourth nozzle hole 2d at the time t254 is landed on the same center of the bank as the ink ejected from the first nozzle hole 2a without any deviation. In the third embodiment, at time t64, the ink ejected from the second nozzle hole 2b lands on the same center of the bank as the ink ejected from the first nozzle hole 2a and has no deviation, and all the nozzles thereafter. Has landed in the center of the bank. From the above, the relationship between the integer n and the periodicity was confirmed.

  Since Lny × n is a deviation in periodicity in the y direction, if Lny × n is smaller than a human-recognizable spatial period λv (80 μm), the deviation in periodicity is caused as striped unevenness by human eyes. It can be prevented from being recognized. Therefore, when determining each value in Equation 2, it is desirable to make n as small as possible.

  Further, in the first embodiment, since Lnx = 169.3333 μm is fixed, there is no need to rotate the inkjet head 2, and as a result, the position of each nozzle hole does not particularly change in the X direction, and Lnx is constant. It becomes.

  FIG. 6A to FIG. 6D show the ink landing results in the bank that summarize the above. In FIGS. 6A to 6D, 3a indicates the landing position of the ink in the bank 1a.

  6A shows the landing state of ink in the bank in the first embodiment, and FIG. 6B shows the landing state in the bank in the second embodiment. ) Shows the landing state in the bank in the third embodiment. FIG. 6D shows a landed state in the bank when printing is performed in a state in which there is a deviation in print timing between a plurality of nozzles by the operation of the conventional example, which is used in the second embodiment. The landing state in the bank when the substrate 1 (Lpx = 256 μm) was applied with a resolution of 256 μm / 121 = 2.115702 μm is shown.

  A comparison will be made between FIG. 6A of the first embodiment and FIG. 6C of the third embodiment where the bank interval Lpx is equivalent to 316 μm and 317.5 μm.

  In this case, compared with the case of Example 1 shown in FIG. 6A, the case of Example 3 shown in FIG.

  In the third embodiment, the nozzle interval Lnx (169.33333 μm) in the x direction of the inkjet head 2 is an integer multiple of the printing resolution Rx (2.64583333 μm), and the bank interval Lpx (317.5 μm) is This is because there is no positional deviation because the relation is an integral multiple of the printing resolution Rx (2.64583333 μm).

  Next, FIG. 6B of the second embodiment in which the bank interval Lpx is the same 256 μm is compared with the case of FIG. 6D of the conventional example.

  In the case of the conventional example shown in FIG. 6D in which printing is performed in a state where there is a deviation in printing timing between a plurality of nozzles, there is little landing deviation between many adjacent nozzles, but printing scanning is performed. In the y direction orthogonal to the direction x, positional deviation occurs at intervals of 0.57 mm, and since it is a value of 80 μm or more, which is the distance of the spatial frequency that can be recognized by humans, it is recognized as striped unevenness. End up.

  On the other hand, in the case of Example 2 of the first embodiment using each value determined so that Formula 2 shown in FIG. 6B, even if the bank interval Lpx to be printed changes. Although the error pattern changes, since the period of the positional deviation repeated in the y direction orthogonal to the print scanning direction x is minute, a person does not recognize it as striped unevenness.

  Therefore, even when the inkjet head 2 cannot be rotated, if the inkjet printing apparatus according to the first embodiment is used, a good printing result without striped unevenness can be obtained.

  As described above, the nozzle interval Lpx in the print scanning direction x of the inkjet head, the print resolution Rx, and the values related to the bank interval Lpx of the printing medium using the formulas 2 are used, and in particular, the nozzle interval in the print scanning direction. By determining the numerical value of Lnx so that it is constant regardless of the bank interval Lpx on any substrate, the periodicity of ink landing position deviation during printing can be suppressed, and the occurrence of striped unevenness can be suppressed. it can.

  In the first embodiment, the nozzle interval Lnx is fixed to one common value for a plurality of types of substrates 1 having different bank intervals, and the print resolution Rx for each substrate is determined. The resolution Rx is fixed to one value common to each substrate, and the nozzle interval Lnx for each substrate is determined. When changing the substrate to be printed, the inkjet is performed so that the nozzle interval Lnx according to the substrate is obtained. The attachment angle of the nozzle 2 may be changed.

  Further, in the first embodiment, the configuration in which printing is performed on a plurality of types of substrates 1 with different bank intervals without replacing the inkjet head 2 or adjusting the angle has been described. Inkjet printing on one type of substrate Also in the printing apparatus, the bank interval in the printing scan direction of the substrate 1 is Lpx, the nozzle interval in the printing scan direction of the inkjet head 2 is Lnx, the nozzle interval in the direction orthogonal to the printing scan direction of the inkjet head 2 is Lny, and the substrate 2 If the printing resolution of Rx is Rx, Lpx, Lnx, Lny and Rx may be determined so that Equation 1 is satisfied, and printing on the substrate 1 may be performed using those determined values.

  As an inkjet head 2 that does not cause striped unevenness that is recognized by humans, it can be designed by a number of combinations of Lpx, Lnx, Lny, and Rx, so that the mounting position and size of the inkjet head 2 are limited, Flexible design is possible.

  Further, even when another substrate having a bank interval different from the substrate for which each value for which Equation 1 is established is printed, the determined nozzle interval Lnx is fixed and the bank interval Lpx of the other substrate is used. If the value of Rx can be determined for the printing resolution that satisfies Equation 1, by using Rx as the printing resolution, striped unevenness can be applied to another substrate without replacing the inkjet head 2 or adjusting the angle. It is possible to perform printing that does not occur.

  In the first embodiment, the case where printing is performed using an inkjet head having an inch-type nozzle interval on a display panel having a pixel interval in units of μm has been described. The present invention can be applied even when the unit system is the same. That is, even when these unit systems are the same, it is possible to prevent the occurrence of striped unevenness that occurs periodically by determining and using each value that satisfies Equation 1 or Equation 2.

  In the first embodiment, the substrate 1 is moved with respect to the fixed inkjet head 2. However, the substrate 1 may be moved relative to the inkjet head 2, and the fixed substrate 1 is fixed. In contrast, the inkjet head 2 may be moved, or the substrate 1 and the inkjet head 2 may be moved together.

  As described above, by determining the nozzle interval Lnx in the printing scanning direction by the inkjet printing apparatus and the control method thereof according to the present invention, it is not necessary to replace the inkjet head or adjust the angle, and a striped pattern with a simple mechanism. Unevenness can be eliminated. Thereby, even in a configuration in which a plurality of inkjet heads are arranged side by side, the same method can be applied without replacing the inkjet head.

  The ink jet printing apparatus and the control method thereof according to the present invention have the effect of eliminating striped color unevenness caused by the relationship between the bank interval and the nozzle interval without requiring replacement of the ink jet head or angle adjustment, It is useful as a light emitting layer of a display panel for a display device such as an EL, an ink jet printing apparatus used for other coating processes, a control method thereof, and the like.

DESCRIPTION OF SYMBOLS 1 Board | substrate 1a, 1b, 1c, 1d, 1e Bank 2 Inkjet head 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h Nozzle hole 3 Moving stage 3a Ink landing position 4 Inkjet controller 4a Position detector 4b Discharge timing Generator 4c Drive signal generator 4d Print data generator 4e Drive signal selector 11 Substrate 11a, 11b, 11c, 11d, 11e Bank 12 Inkjet head 12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h Nozzle hole 13 Ink 13a Ink landing position 14 Inkjet controller 15, 15a Print timing signal

Claims (6)

Ink is supplied from each nozzle of an inkjet head having a plurality of nozzles according to a predetermined printing timing to a substrate on which a bank having an interval corresponding to the pixel interval is arranged, which is used for a display panel having a fixed pixel interval. A method of controlling an inkjet printing apparatus, wherein the substrate is moved relative to the inkjet head in a printing scan direction relative to the inkjet head while supplying ink to each bank by discharging,
Lpx is a bank interval in the print scanning direction of the substrate, Lnx is a nozzle interval in the print scanning direction of the inkjet head, Lny is a nozzle interval in a direction orthogonal to the printing scan direction of the inkjet head, and intermittent of the substrate. Control method for an ink jet printing apparatus that determines Lpx, Lnx, Lny, and Rx so that Equation 1 is satisfied, and uses the determined values to print on the substrate, where Rx is the print resolution that is the target movement amount .

A plurality of display panels each having a fixed pixel interval, and at least a bank of intervals corresponding to each pixel interval is used for the plurality of display panels having different pixel intervals between a pair of display panels. Ink is supplied to each bank by ejecting ink according to a predetermined printing timing from each nozzle of an inkjet head having a plurality of nozzles to a plurality of substrates (u; u is an integer of 2 or more) While, the control method of the ink jet printing apparatus for moving each of the substrates relative to the ink jet head in a printing scan direction relatively and intermittently,
Lpx (i) is the bank interval in the print scanning direction for each substrate i (i = 1, 2,..., U), Lnx is the nozzle interval in the print scanning direction of the inkjet head, and the Assuming that the nozzle interval in the direction orthogonal to the print scanning direction is Lny and the print resolution, which is the amount of intermittent movement for each substrate i, is Rx (i), Equation 2 is established after fixing Lnx and Lny. And a method of controlling an inkjet printing apparatus that determines Lpx (i) and Rx (i) for each substrate i and prints on each substrate i using the determined values.

  The method of controlling an ink jet printing apparatus according to claim 1, wherein the Lnx is a value that is a circulation decimal with one digit in the circulation node. Ink is supplied from each nozzle of an inkjet head having a plurality of nozzles according to a predetermined printing timing to a substrate on which a bank having an interval corresponding to the pixel interval is arranged, which is used for a display panel having a fixed pixel interval. An ink jet printing apparatus that moves the substrate relative to the ink jet head in a print scanning direction relatively and intermittently while supplying ink to each bank by discharging,
Lpx is a bank interval in the print scanning direction of the substrate, Lnx is a nozzle interval in the print scanning direction of the inkjet head, Lny is a nozzle interval in a direction orthogonal to the printing scan direction of the inkjet head, and intermittent of the substrate. Inkjet printing provided with a control unit that controls printing on the substrate using the values of Lpx, Lnx, Lny and Rx determined so that Equation 1 is satisfied when the printing resolution that is the amount of movement is Rx apparatus.

A plurality of display panels each having a fixed pixel interval, and at least a bank of intervals corresponding to each pixel interval is used for the plurality of display panels having different pixel intervals between a pair of display panels. Ink is supplied to each bank by ejecting ink according to a predetermined printing timing from each nozzle of an inkjet head having a plurality of nozzles to a plurality of substrates (u; u is an integer of 2 or more) An inkjet printing apparatus that moves each of the substrates relative to the inkjet head in a print scanning direction relatively and intermittently,
Lpx (i) is the bank interval in the print scanning direction for each substrate i (i = 1, 2,..., U), Lnx is the nozzle interval in the print scanning direction of the inkjet head, and the Assuming that the nozzle interval in the direction orthogonal to the print scanning direction is Lny and the print resolution, which is the amount of intermittent movement for each substrate i, is Rx (i), Equation 2 is established after fixing Lnx and Lny. An inkjet printing apparatus provided with a control unit that controls printing on each of the substrates i using the values of Lpx (i) and Rx (i) for each of the substrates i determined in (1).

  The inkjet printing apparatus according to claim 4 or 5, wherein the Lnx is a value that is a circulation decimal with one digit in the circulation node.

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