Printing control apparatus, printing apparatus, and printing control method

Abstract

To provide a printing control apparatus, a printing apparatus, and a printing control method capable of accurately discharging ink even in a small cell.SOLUTION: A printing control apparatus includes: a calculation unit that calculates a resolution in a printing scanning direction necessary for discharging of ink to a region based on an interval in the printing scanning direction of a plurality of nozzles that discharge ink and length in the printing scanning direction of the region in each cell in which landing of ink is allowed; and a nozzle control unit that controls discharge timing of ink from the plurality of nozzles in the printing scanning direction based on the resolution.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a printing control device, a printing device, and a printing control method.

Background Art

[0002] Conventionally, as a method for forming an organic light-emitting layer of an organic display, a method of discharging ink from a printing device having an inkjet head and applying the ink to cells of a display panel is known.

[0003] For example, Patent Document 1 discloses a technique in which there is a non-discharging nozzle that cannot discharge ink, and when the number of nozzles for discharging ink to a certain cell is insufficient, ink is discharged from another nozzle to the cell a plurality of times to compensate for the shortage.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, the size of cells for discharging ink has been becoming smaller and smaller, and it is desired to develop a printing device that can accurately discharge ink to a predetermined area of a cell even for a small cell.

[0006] An object of the present disclosure is to provide a printing control device, a printing device, and a printing control method that can accurately discharge ink even for a small cell.

Means for Solving the Problems

[0007] A printing control device according to an aspect of the present disclosure includes a calculation unit that calculates a resolution in a printing scan direction required for discharging ink onto a region based on an interval in the printing scan direction of a plurality of nozzles that discharge ink and a length in the printing scan direction of a region within each cell that allows the ink to land, and a nozzle control unit that controls a discharge timing of the ink from the plurality of nozzles in the printing scan direction based on the resolution.

[0008] A printing device according to an aspect of the present disclosure includes the above-described printing control device.

[0009] A printing control method according to an aspect of the present disclosure includes a calculation step of calculating a resolution in a printing scan direction required for discharging ink onto a region based on an interval in the printing scan direction of a plurality of nozzles that discharge ink and a length in the printing scan direction of a region within each cell that allows the ink to land, and a nozzle control step of controlling a discharge timing of the ink from the plurality of nozzles in the printing scan direction based on the resolution.

Advantages of the Invention

[0010] According to the present disclosure, ink can be discharged accurately even in a small cell.

Brief Description of the Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below shows a specific example of the present disclosure. Therefore, each component shown in the following embodiments, the arrangement position and connection form of each component, as well as each step and the order of each step, etc. are examples and are not intended to limit the present disclosure. In addition, among the components in the following embodiments, the components not described in the independent claims are described as optional components.

[0013] Each figure is a schematic diagram and is not necessarily drawn precisely. In each figure, substantially the same components are denoted by the same reference numerals, and overlapping descriptions are omitted or simplified.

[0014] First, problems of a conventional printing apparatus for applying ink to cells of a display panel will be described. FIG. 1A is a diagram showing a head 101 and a display panel 121 of a conventional printing apparatus. The head 101 has a plurality of nozzle holes 102 and discharges ink 114 from the nozzle holes 102. Also, the head 101 is tilted and arranged in an oblique direction. Four nozzles N1 to N4 are formed in the head 101 at equal intervals. Actually, a large number of nozzles are formed in the head 101.

[0015] The display panel 121 has rectangular cells 112 and rectangular landing regions 113 which are regions in the cells 112 that allow ink to land. A plurality of inks are discharged from the nozzle holes 102 of the head 101, and the ink 114 is applied to the landing region 113. Hereinafter, the cell 112 in the first row of the display panel 121 is referred to as cell C1, the cell 112 in the second row is referred to as cell C2, and so on.

[0016] FIG. 1B is a diagram for explaining the landing deviation of ink in the nozzle direction. The nozzle direction is a direction orthogonal to the printing scanning direction which is the vertical direction in FIG. 1A. As shown in FIG. 1B, the actual landing positions of the ink 114 are shifted left and right from the centers of the cells C1 and C2. And an allowable range A is set for the amount of the shift.

[0017] FIGS. 2A and 2B are diagrams showing a conventional ink application method. Since the landing deviation amount of the nozzle N4 in the nozzle direction exceeds the allowable range A, it is treated as a non-discharging nozzle. In this case, the position of the head 101 is shifted and the nozzle N4 is complemented by the nozzle N3.

[0018] Therefore, as shown in FIG. 2A, nozzles N1 and N2 fill the first and second drops of ink into cell C1 respectively, and nozzle N3 fills the first drop of ink into cell C2. Then, as shown in FIG. 2B, nozzle N3 fills the second drop of ink into cell C2.

[0019] FIG. 3A is a diagram showing a display panel 121 with a small cell size in the nozzle direction. The cell size in the nozzle direction of the square cell 122 in FIG. 3A is smaller than that of the cell 112 in FIG. 1A. Also, the size in the nozzle direction of the rectangular landing area 123 is smaller than that of the landing area 123 in FIG. 1.

[0020] FIG. 3B is a diagram for explaining the landing deviation of ink in the nozzle direction. Since the size of cell 122 is small, the allowable range B for landing deviation is set strictly. As a result, the nozzles printable in cell 122 are narrowed down.

[0021] FIGS. 4A and 4B are diagrams showing an ink application method when the cell size in the nozzle direction is small. Since the amount of landing deviation of nozzles N3 and N4 in the nozzle direction exceeds the allowable range B, they are treated as non-ejecting nozzles. In this case, the position of head 101 is shifted, and nozzles N3 and N4 are complemented by nozzles N1 and N2.

[0022] Therefore, as shown in FIG. 4A, nozzle N1 fills the first drop of ink into cell C1, and N2 fills the first drop of ink into cell C2. Then, as shown in FIG. 4B, head 101 is shifted by n times (n is an integer) the nozzle interval, nozzle N1 fills the first drop of ink into cell C3, and nozzle N2 fills the first drop of ink into cell C4.

[0023] Thus, in the prior art, when the size of the cell in the nozzle direction is small, there is a problem that the number of nozzles that can be used decreases.

[0024] FIG. 5A is a diagram showing nozzles with intervals different from the intervals between cells of a display panel. In the example of FIG. 5A, the direction in which nozzles 102 are arranged coincides with the nozzle direction perpendicular to the printing scan direction. Also, the intervals between nozzles N1 to N4 and the intervals between cells C1 to C5 are different. When ink is to be landed in the landing area 123, due to these different intervals, nozzles other than nozzle N1 cannot be used.

[0025] FIG. 5B is a diagram for explaining the deviation of ink landing in the nozzle direction. Since the size of cell 122 is small, the allowable range C of landing deviation is set strictly. As a result, the nozzles printable within cell 122 are narrowed down.

[0026] Thus, when the intervals between nozzles 102 and the intervals between cells 122 are different, in the prior art, there is a problem that the number of available nozzles is further reduced. Also, in the conventional ink application method, when the intervals between nozzles 102 and the intervals between cells are different, there is a problem that nozzles that seemingly can be used actually cannot be used.

[0027] (Embodiment 1) FIG. 6 is a schematic diagram showing a printing apparatus 1 in Embodiment 1. The printing apparatus 1 includes an inkjet head module 10, a printing control device 20, and a stage 30. A display panel 12 is placed on the stage 30. Also, an external host PC (Personal Computer) 2 is connected to the control device 20 by wire or wirelessly.

[0028] The inkjet head module 10 discharges ink droplets onto the display panel 12 placed on the stage 30. The operation of the inkjet head module 10 including the discharge of ink droplets is controlled by the printing control device 20.

[0029] The printing control device 20 controls the entire printing device 1. For example, the printing control device 20 receives printing image data from an external host PC2 connected thereto, and based on the received printing image data, causes an image to be formed on the display panel 12. At that time, the control device 20 controls the ejection timing and volume of ink droplets from the inkjet head module 10 in conjunction with the operation of the stage 30.

[0030] The stage 30 is configured to be movable relative to the inkjet head module 10, for example, and conveys the placed display panel 12. Then, by conveying the display panel 12, the stage 30 changes the relative positional relationship between the display panel 12 and the inkjet head module 10.

[0031] Also, the stage 30 includes an encoder device (not shown), generates an encoder signal, and outputs it to the printing control device 20. The encoder signal is a signal including information indicating the conveyance speed (stage movement amount) and direction of the display panel 12.

[0032] Note that in this example, the stage 30 has been described as being configured to be movable, but the configuration of the printing device 1 is not limited to this example. For example, the configuration of the printing device 1 may be such that the stage 30 is fixed and the inkjet head module 10 moves, or both the inkjet head module 10 and the stage 30 may move.

[0033] Furthermore, the configuration of the printing device 1 is not limited to the example shown in FIG. 6. For example, the printing device 1 may be configured as a so-called roll-to-roll facility that forms an image on a printing object such as a film wound in a roll shape and then winds it up in a roll shape.

[0034] FIG. 7 is a block diagram showing an example of the configuration of the printing control device 20 in Embodiment 1. The printing control device 20 includes a CPU (Central Processing Unit) 21, a RAM (Random Access Memory) 22, a ROM (Read Only Memory) 23, a host interface 24, a synchronization control unit 25, a head control unit 26, and a head drive unit 27. Further, the CPU 21, the RAM 22, the ROM 23, the host interface (hereinafter, appropriately referred to as "host I / F") 24, and the head control unit 26 are connected to a CPU bus 28.

[0035] The CPU 21 reads a program corresponding to the processing content from the ROM 23 and expands it in the RAM 22, and controls the operation of the printing device 1 in cooperation with the expanded program. The RAM 22 is, for example, a volatile memory, and temporarily stores various data used in the printing device 1. For example, in Embodiment 1, the printing image data transmitted from the host PC 2 is temporarily stored in the RAM 22. The ROM 23 is, for example, a non-volatile memory, and stores various data such as constant data used in the printing control device 20.

[0036] Furthermore, the CPU 21 functions as a calculation unit 21a, a generation unit 21b, a detection unit 21c, and a nozzle control unit 21d.

[0037] The calculation unit 21a performs processes such as calculating the resolution in the printing scan direction and the resolution in the nozzle direction required for ink ejection into the areas within each cell. The generation unit 21b extracts nozzles capable of ejecting ink into the landing areas within each cell from among a plurality of nozzles, and generates data indicating the extracted nozzles.

[0038] The detection unit 21c detects the ejection accuracy of a plurality of nozzles based on the landing positions of the ejected ink while actually moving the head. The nozzle control unit 21d controls the ink ejection timing from a plurality of nozzles in the printing scan direction and the nozzle direction. The processes performed by each unit realized by the CPU 21 will be described in more detail later.

[0039] The host I / F 24 is an interface for exchanging various data with an external host PC2. For example, the host I / F 24 receives print image data from the host PC2 and stores the received print image data in the RAM 22 via the CPU bus 28 according to the instructions of the CPU 21.

[0040] The synchronization control unit 25 generates a basic printing timing signal based on the encoder signal received from the stage 30. The basic printing timing signal indicates a timing signal for starting unit ejection. Unit ejection refers to the ejection of ink for forming one pixel.

[0041] The head control unit 26 generates a drive voltage waveform signal for driving the head 10 of the inkjet head module 10.

[0042] The head drive unit 27 converts the drive voltage waveform signal generated by the head control unit 26 into a signal suitable for being handled by the inkjet head module 10 and outputs it. Specifically, the head drive unit 27 converts the drive voltage waveform signal from a digital signal to an analog signal and performs voltage amplification and current amplification.

[0043] The head control unit 26 and the head drive unit 27 function as a driving device for the head 10. The functions of the head control unit 26 and the head drive unit 27 may be realized by a computer having, for example, a CPU, a ROM, and a RAM (none of which are shown).

[0044] The CPU reads out a program corresponding to the processing content from the ROM and expands it in the RAM, and centrally controls the operations of the head control unit 26 and the head drive unit 27 in cooperation with the expanded program. Also, the functions of the head control unit 26 and the head drive unit 27 may be realized by the CPU 21, the ROM 23, and the RAM 22 provided in the control device 20, for example.

[0045] FIG. 8 is a flowchart showing the printing method in Embodiment 1. First, the calculation unit 21a of the print control device 20 calculates the resolution in the print scanning direction (step S1). Then, the generation unit 21b generates print data in which the positions of the regions within each cell that ejects ink are registered as vector data (step S2).

[0046] Subsequently, the detection unit 21c performs a landing inspection to actually eject ink from the nozzles and detect the ejection accuracy of the nozzles from the landing positions (step S3). Then, the nozzle control unit 21d selects usable nozzles in which the amount of landing deviation is within the allowable range based on the results of the landing inspection (step S4).

[0047] Thereafter, the nozzle control unit 21d searches for nozzles capable of ejecting ink onto the landing regions within each cell from among the selected nozzles, and generates nozzle data including the data of the searched nozzles (step S5). Then, the nozzle control unit 21d executes printing by referring to the nozzle data and ejecting ink onto the nozzles (step S6).

[0048] FIGS. 9A and 9B are diagrams showing a method for determining the resolution in the print scanning direction shown in step S1 of FIG. 8. As shown in FIG. 9A, the head 10 has a plurality of nozzle holes 11, and ejects ink from the nozzle holes 11. Four nozzles N1 to N4 are formed in the head 10 at equal intervals. In the example of FIG. 9A, only one row of nozzles is shown in the print scanning direction, but in order to increase the resolution of the head, a plurality of nozzle rows shifted by 1 / n of the nozzle pitch (n is an integer) in the nozzle direction may be arranged at intervals in the print scanning direction.

[0049] The display panel 12 has square cells 13 and square landing regions 14 that are regions within the cells 13 that allow the landing of ink. A plurality of inks 15 are ejected from the nozzle holes 11 of the head 10 and applied to the landing regions 14. Note that the shapes of the cells 13 and the landing regions 14 are not limited to squares, and may be other shapes such as rectangles.

[0050] As shown in FIG. 9B, when the size of cells C1 to C5 in the printing scanning direction is 20.0 μm, if the droplet diameter 20 of the ink is 12.0 μm and the landing margin, which is a preliminary width to prevent the ink from overflowing from cells C1 to C5, is 1.0 μm, then the size of the landing area where the ink lands in the printing scanning direction is 6.0 μm according to the formula: size of the landing area in the printing scanning direction = cell size - droplet diameter - landing margin × 2.

[0051] Also, since the resolution of the nozzles in the printing scanning direction is 1,200 dpi, it is 21.167 μm.

[0052] In this case, the calculation unit 21a calculates the resolution magnification by rounding up the decimal part of the quotient obtained by dividing the interval between the nozzles in the printing scanning direction by the length of the landing area in the printing scanning direction within each cell. In the example of FIG. 9B, the calculation unit 21a rounds up the decimal part of 21.167÷6.0 = 3.527 and calculates the value of the resolution magnification as 4.

[0053] Then, the calculation unit 21a calculates the resolution required for printing by multiplying the resolution of the nozzles by the resolution magnification. In the example of FIG. 9B, the calculation unit 21a calculates the resolution required for printing as 1,200×4 = 4,800 dpi.

[0054] Furthermore, the calculation unit 21a calculates the resolution required for printing by dividing the resolution of the nozzles by the resolution magnification. In the example of FIG. 9B, the calculation unit 21a calculates the resolution required for printing as 21.167 μm÷4 = 5.292 μm.

[0055] Since the length of the landing area in the printing scanning direction is 6.0 μm and the resolution required for printing is 5.292 μm, which is smaller than 6.0 μm, the printing control device 20 can appropriately land the ink on the landing area.

[0056] FIG. 10 is a diagram showing print data in which information on cells that eject ink is registered. The print data includes the x coordinate and y coordinate indicating the landing area within the cell, the landing area width which is the width in the nozzle direction (x direction) of the landing area, the landing area height which is the width in the print scanning direction (y direction) of the landing area, and information on the number of ink droplets to be ejected onto the landing area.

[0057] In FIG. 10, the position of the landing area within the cell is held as vector data. If the position is held as pixel data instead of vector data, the print resolution in the nozzle direction becomes a value obtained by dividing the nozzle pitch by an integer n and does not match the cell pitch. Therefore, quantization error occurs in the print position when printing using pixel data. On the other hand, when using vector data, quantization error does not occur until the stage of determining the nozzles to be printed, so the occurrence of quantization error can be minimized.

[0058] FIG. 11 is a diagram showing a method of landing inspection in step S3 of FIG. 8. Ink is ejected from the nozzle 11 of the head 10, and the ink droplet 42 lands on the landing inspection substrate 41. On the landing inspection substrate 41, ink lands from nozzles N1 to N4, and the offset and variation from the stop position which is the landing target are detected.

[0059] FIG. 12 is a flowchart showing a process of selecting available nozzles based on the landing inspection result shown in FIG. 11. First, the detection unit 21c of the print control device 20 acquires landing data which is the result of landing ink droplets 42 on the landing inspection substrate 41 n times (n is an integer) (step S11). This landing data can be obtained, for example, by detecting the landing position of the ink using a camera or the like. The landing data includes data on the landing position of the ink in the nozzle direction and data on the landing position of the ink in the print scanning direction.

[0060] Subsequently, the detection unit 21c calculates the error of the landing position by the following formula (step S12). Note that i is an integer where 1 ≦ i ≦ n. 1. Error of landing position in nozzle direction [i] = Landing position in the nozzle direction [i] - Landing target position in the nozzle direction [i] 2. Error [i] of the landing position in the printing scan direction = Landing position in the printing scan direction [i] - Landing target position in the printing scan direction [i]

[0061] Then, the detection unit 21c calculates the offset from the center of the landing position and the variation of the landing position indicating the reproducibility of the landing position by the following formula (step S13). 3. Offset from the center of the landing target position in the nozzle direction = Average value of the error [i] of the landing position in the nozzle direction 4. Variation of the landing position in the nozzle direction = Standard deviation of the error [i] of the landing position in the nozzle direction × 3 5. Offset from the center of the landing target position in the printing scan direction = Average value of the error [i] of the landing position in the printing scan direction 6. Variation of the landing position in the printing scan direction = Standard deviation of the error [i] of the landing position in the printing scan direction × 3

[0062] After that, the detection unit 21c sets the nozzles with non-reproducible ink landing positions as non-ejecting nozzles that prohibit ink ejection (step S14). For example, the detection unit 21c sets the nozzles with a standard deviation calculated by Equations 4 and 6 of 1.0 μm or more as non-ejecting nozzles.

[0063] In addition, the detection unit 21c sets the nozzles with an offset from the center of the landing target position in the printing scan direction exceeding the threshold as correction nozzles that correct the timing of ink ejection (step S15). In this case, the offset calculated by Equation 5 is used as data for calculating the timing of ink ejection.

[0064] Figures 13A and 13B are conceptual diagrams showing the process of searching for available nozzles in step S5 of FIG. 8. As shown in FIG. 13A, when the width of the work 52 to which ink is to be ejected is larger than the head 51, while moving the head 51 at predetermined search intervals, nozzles capable of ejecting ink into each cell of the work 52 are searched for.

[0065] Also, as shown in FIG. 13B, when the head 53 is larger than the width of the work 54, while moving the work 54 at predetermined search intervals, nozzles capable of ejecting ink into each cell of the work 52 are searched for. In the following, the case of moving the head 51 shown in FIG. 13A will be taken as an example for explanation.

[0066] FIG. 14 is a flowchart showing the process of searching for nozzles available for ejecting ink into the landing areas within each cell. First, the generation unit 21b of the print control device 20 performs the extraction process of nozzles available for ejecting ink into the landing areas within each cell for each search position where the head 51 has moved with respect to the work 52 (step S21).

[0067] Then, the generation unit 21b performs the selection process of the search position of the head 51 and nozzles to be actually used for printing from among the extracted nozzles (step S22). This selection process will be described in detail with reference to FIGS. 18A to 18F.

[0068] Thereafter, the generation unit 21b performs the process of generating print control data indicating the selected search position and nozzles (step S23). The nozzle control unit 21d refers to this print control data, selects nozzles available for ink ejection for each search position, and controls printing.

[0069] FIG. 15 is a flowchart showing the extraction process of available nozzles in step S21 of FIG. 14. The generation unit 21b of the print control device 20 sequentially selects the position of the head 51 with respect to the work 52 at a predetermined search interval from the search start position to the search end position (step S31).

[0070] Further, the generation unit 21b sequentially selects each cell at each position of the head 51 (step S32). Further, the generation unit 21b sequentially selects each nozzle for each position of the heads 41 and 53 and each cell (step S33).

[0071] Then, the generation unit 21b determines whether there is a nozzle capable of ejecting ink onto the landing area within the cell. If there is such a nozzle, it holds the cell number of the cell onto which the ink from that nozzle can land, the search number indicating the search position onto which the ink from that nozzle can land, the nozzle number of that nozzle, and information on the deviation amount of the landing position from the center position of the landing area in the nozzle direction of that nozzle (step S34).

[0072] FIG. 16 is a diagram showing holding data regarding nozzles capable of ejecting ink onto the landing area within the cell. This holding data registers each of the above-described pieces of information.

[0073] If the process of step S34 has not been completed for each nozzle, the process returns to step S33, and the next nozzle is selected (step S35). If the process of step S34 has been completed for each nozzle, the process proceeds to step S36. And if the processes from step S33 to step S35 have not been completed for each cell, the process returns to step S32, and the next cell is selected (step S36).

[0074] If the processes from step S33 to step S35 have been completed for each cell, the generation unit 21b detects the number of nozzles capable of ejecting ink onto the area within each cell for each search position of the head 51, and holds that data (step S37).

[0075] FIG. 17 is a diagram showing nozzle number data indicating the number of nozzles capable of ejecting ink onto the area within each cell. This nozzle number data registers the number of nozzles capable of ejecting ink onto the area within each cell at the search position corresponding to each search number.

[0076] Then, for each search position, if the processes from step S32 to step S37 have not been completed, the process returns to step S31, and the next search position is selected (step S38). For each search position, if the processes from step S32 to step S37 have been completed, this extraction process ends.

[0077] Figures 18A to 18E are flowcharts showing the search position and nozzle selection processes in step S22 of FIG. 14.

[0078] First, the generation unit 21b of the print control device 20 receives from the user a specification of the nozzle selection mode (step S41). The nozzle selection modes include the same cell usage nozzle dispersion mode, the misregistration minimization mode, the minimum number of printing times mode, and the volume error minimization mode. In addition to receiving the selection mode from the user at this timing, the user may be allowed to input and store the selection mode in advance, and the information may be read out at this timing.

[0079] Then, the generation unit 21b executes the search position and nozzle selection processes in each mode according to which mode is selected (steps S42 to S45).

[0080] In step S41, when the same cell usage nozzle dispersion mode is specified, as shown in FIG. 18B, the generation unit 21b sequentially selects each cell (step S46). Then, the generation unit 21b sequentially selects each nozzle extracted in step S34 of FIG. 15 (step S47).

[0081] Then, the generation unit 21b extracts different nozzles capable of discharging ink onto the landing area within one cell with reference to the holding data shown in FIG. 16 (step S48).

[0082] When ink is ejected multiple times onto a landing area within a single cell, by using different nozzles, it is possible to offset the deviation in ejection volume for each nozzle and reduce the luminance unevenness of the display. Since adjacent nozzles in the vicinity tend to have the same ejection volume, it is preferable to extract non - adjacent nozzles that are as far apart as possible.

[0083] And when the process of step S48 has not been completed for each nozzle, the process returns to step S47 and the next nozzle is selected (step S49). When the process of step S48 has been completed for each nozzle, the generation unit 21b determines whether the process from step S47 to step S49 has been completed for each cell (step S50).

[0084] And when the process from step S47 to step S49 has not been completed for each cell, the process returns to step S46 and the next cell is selected. When the process from step S47 to step S49 has been completed for each cell, this search position and nozzle selection process ends.

[0085] In step S41, when the misregistration minimization mode is specified, as shown in FIG. 18C, the generation unit 21b sequentially selects each cell (step S51). Then, the generation unit 21b sequentially selects each nozzle extracted in step S34 of FIG. 15 (step S52).

[0086] Then, the generation unit 21b refers to the holding data shown in FIG. 16, and sequentially selects from the combinations of search positions and nozzles with a small deviation amount from the ink landing target position in the landing area within each cell among the plurality of nozzles, and extracts search positions and nozzles capable of ejecting ink onto the landing area within each cell (step S53).

[0087] And, when the process of step S53 has not been completed for each nozzle, the process returns to step S52 and the next nozzle is selected (step S54). When the process of step S53 has been completed for each nozzle, the generation unit 21b determines whether the process from step S52 to step S54 has been completed for each cell (step S55).

[0088] And, when the process from step S52 to step S54 has not been completed for each cell, the process returns to step S51 and the next cell is selected. When the process from step S52 to step S54 has been completed for each cell, this search position and nozzle selection process ends.

[0089] In step S41, when the printing times minimization mode is specified, as shown in FIG. 18D, the generation unit 21b sequentially selects each cell (step S56). Then, the generation unit 21b sequentially selects each nozzle extracted in step S34 of FIG. 15 (step S57).

[0090] Then, the generation unit 21b refers to the nozzle number data shown in FIG. 17, and sequentially selects from the positions with a larger number of nozzles among the positions of the heads indicated by the search numbers, and extracts the nozzles capable of discharging ink at the selected positions with reference to the holding data shown in FIG. 16 (step S58).

[0091] And, when the process of step S58 has not been completed for each nozzle, the process returns to step S57 and the next nozzle is selected (step S59). When the process of step S58 has been completed for each nozzle, the generation unit 21b determines whether the process from step S57 to step S59 has been completed for each cell (step S60).

[0092] And, when the process from step S57 to step S59 has not been completed for each cell, the process returns to step S56 and the next cell is selected. When the process from step S57 to step S59 has been completed for each cell, this search position and nozzle selection process ends.

[0093] In step S41, when the volume error minimization mode is specified, as shown in FIG. 18E, the generation unit 21b sequentially selects each cell (step 61). Then, the generation unit 21b sequentially selects each nozzle extracted in step S34 of FIG. 15 (step S62).

[0094] Then, the generation unit 21b refers to the ink volume data shown in FIG. 18F, and for each cell, extracts nozzles that can make the total volume of the droplets landing in the landing area within the cell approach the target total (step S63).

[0095] FIG. 18F is a diagram showing ink volume data in which information on the volume of ink ejected from each nozzle is registered. This ink volume data registers the cell number of the cell where the ink from the nozzle can land, the search number indicating the search position where the ink from the nozzle can land, the nozzle number of the nozzle, and information on the volume of ink ejected from the nozzle.

[0096] Here, the target total volume of the droplets is calculated by (expected volume) × (number of droplets to land in the area within the cell). Here, the expected volume is the target value for volume adjustment by each nozzle. This expected volume is approximately equal to the average value of the volumes of ink ejected from each nozzle. Also, the number of droplets to land in the area within the cell is the number of droplets shown in FIG. 10.

[0097] For example, when the expected volume is 5 pl and the number of droplets to land in the area within the cell is 2, the target total volume of the droplets is 10 pl. In this case, the generation unit 21b refers to the ink volume data shown in FIG. 18F, and for the cell with cell number 1, extracts the nozzle with nozzle number 1 at the position of the head with search number 1. Also, the generation unit 21b extracts the nozzle with nozzle number 5 at the position of the head with search number 2.

[0098] The nozzle with nozzle number 1 can eject 4.8 pl of ink, and the nozzle with nozzle number 5 can eject 5.2 pl of ink. Thus, the total volume of the ink ejected for the cell with cell number 1 can be made equal to the target total of 10 pl.

[0099] Note that the generation unit 21b may extract, as the nozzles for ejecting ink into the area within one cell, the nozzles that can eject ink with a volume closer to the above-described volume expected value. Thereby, the total volume of the droplets landing on the landing area within the cell can be made closer to the target total.

[0100] In this case, the generation unit 21b refers to the ink volume data shown in FIG. 18F and extracts, for the cell with cell number 1, the nozzle with nozzle number 10 at the position of the head with search number 3. This nozzle is a nozzle that can eject ink with a volume of 5.1 pl, which is the volume closest to the volume expected value of 5 pl.

[0101] Also, the generation unit 21b extracts the nozzle with nozzle number 1 at the position of the head with search number 1. This nozzle is a nozzle that can eject ink with a volume of 4.8 pl, which is the volume second closest to the volume expected value of 5 pl.

[0102] Thereby, the total volume of the ink ejected for the cell with cell number 1 can be made 9.9 pl, which is a value close to the target total of 10 pl.

[0103] Here, the nozzle with nozzle number 1 at the position of the head with search number 1 was extracted. However, the nozzle with nozzle number 5 at search number 2, whose difference from the volume expected value is the same 0.2 as that of the said nozzle, may be extracted. However, in this case, since the total volume of the ink ejected for the cell with cell number 1 becomes 10.3 pl, it is desirable to select a combination of nozzles that makes the said total volume smaller.

[0104] Returning to the description of Fig. 18E, if the process of step S63 has not been completed for each nozzle, the process returns to step S62 and the next nozzle is selected (step S64). If the process of step S63 has been completed for each nozzle, the generation unit 21b determines whether the process from step S62 to step S64 has been completed for each cell (step S65).

[0105] Then, if the process from step S62 to step S64 has not been completed for each cell, the process returns to step S61 and the next cell is selected. If the process from step S62 to step S64 has been completed for each cell, this search position and nozzle selection process ends.

[0106] Note that in the above flowchart, the same cell usage nozzle dispersion mode, misregistration minimization mode, printing times minimization mode, and volume error minimization mode have been described, but they may be combined. For example, combining the misregistration minimization mode and the printing times minimization mode, when the deviation from the ink landing target position in the landing area within each cell is within 0.5 μm, the search position and nozzle where the printing times are minimized may be selected.

[0107] Also, in the process described with reference to Figs. 18A to 18E, when it is necessary to land a plurality of ink droplets in the landing area of one cell as shown in Fig. 1A, a plurality of nozzles capable of discharging ink in one scan of the head in the printing scan direction are extracted, and ink is discharged from these plurality of nozzles to the landing area. The effects in this case will be described below.

[0108] Fig. 19 is a diagram showing the probability distribution of the positions where the ink discharged from each nozzle lands in the nozzle direction. The interval between the vertices of each probability distribution corresponds to the resolution of the nozzles in the nozzle direction.

[0109] As the resolution of the nozzles increases, the number of nozzles capable of landing ink on a single landing area 113 increases. Therefore, ink is ejected from a plurality of nozzles onto a single landing area 113 to shorten the printing cycle time.

[0110] For example, as in the case of cell C1 shown in FIG. 1A, it is necessary to land two droplets of ink on a single landing area 113. When it is possible to land two droplets of ink from nozzle N1 and nozzle N2 on a single landing area 113 at a certain search position, ink is ejected from nozzle N1 and nozzle N2 during the head scan in one printing scan direction to shorten the printing cycle time.

[0111] FIGS. 20A and 20B are diagrams for explaining the generation of print control data. As shown in FIG. 20A, when the position of nozzle N1 is at a distance n times (n is an integer) the search interval from the search start position, when ink is ejected from nozzles N1 to N4, the ink lands on cells C1, C2, C4, and C5 in the first and second rows.

[0112] In this case, the generation unit 21b generates print control data 61 indicating the positions where ink is ejected. The nozzle direction numbers in the print control data 61 represent the nozzle numbers 1 to 4 corresponding to nozzles N1 to N4, and the print scan direction numbers indicate the positions where ink is ejected. The numbers assigned to the print scan direction are calculated by the calculation unit 21a and correspond to the resolution required for printing shown in the table of FIG. 9B, that is, the resolution in the print scan direction required for ejecting ink onto each landing area 14. Here, the ninth row of the print control data 61 corresponds to cells C1, C2, C4, and C5 in the first row, and the 19th row of the print control data 61 corresponds to cells C1, C2, C4, and C5 in the second row.

[0113] Furthermore, when the position of the head moves and the position of nozzle N1 becomes a distance m times (m is an integer) the search interval from the search start position, as shown in FIG. 20B, when ink is ejected from nozzle N2, the ink lands on cell C3 in the first and second rows.

[0114] In this case, the generation unit 21b generates print control data 62 indicating the positions where the ink is ejected. In FIG. 20B, since the ink ejected from the nozzle N2 lands on the cells C3 in the first and second columns, in the print control data 62, data indicating the positions where the ink is ejected is registered in the portions corresponding to the nozzle numbers 2 in the 9th and 19th rows.

[0115] The nozzle control unit 21d controls the ejection timing of the ink from a plurality of nozzles in the print scanning direction based on the resolution in the print scanning direction required for ejecting the ink onto each landing area 14. Specifically, the nozzle control unit 21d refers to the print control data generated based on the information on the resolution in the print scanning direction required for ejecting the ink onto each landing area 14, selects the nozzles available for ejecting the ink for each search position, and controls the ejection timing of the ink from the plurality of nozzles to control the printing.

[0116] FIGS. 21A and 21B are diagrams showing ink ejection methods when the intervals between the nozzles and the cells are different. For example, as shown in FIG. 21A, when the nozzle N1 is at a distance that is n times (n is an integer) the search interval from the search start position, the nozzle N1 fills the cell C1 with the first drop of ink, and the nozzle N2 fills the cell C2 with the first drop of ink. Also, the nozzle N3 fills the cell C4 with the first drop of ink, and the nozzle N4 fills the cell C5 with the first drop of ink.

[0117] Also, as shown in FIG. 21B, when the nozzle N1 is at a distance that is m times (m is an integer) the search interval from the search start position, the nozzle N2 fills the cell C3 with the first drop of ink. In this way, by appropriately shifting the position of the nozzle N1 by an integer multiple of the search interval that is neither the nozzle interval nor the cell interval, the ink can be made to land at the center of the cell. Of course, the position of the nozzle N1 may also be moved by an integer multiple of the nozzle interval or the cell interval.

[0118] FIG. 22A and FIG. 22B are diagrams showing a method of discharging ink using a rotary head. In the rotary head, when the cell size in the nozzle direction is small, the head is rotated so as to be inclined with respect to the nozzle direction orthogonal to the printing scan direction, and the nozzle pitch in the nozzle direction can be made equal to or smaller than the cell pitch.

[0119] Also in this case, as in the case shown in FIGS. 21A and 21B, the ink can be discharged to an appropriate position.

[0120] For example, as shown in FIG. 22A, when the nozzle N1 is at a distance n times the search interval from the search start position, the nozzle N2 fills the first drop of ink into the cell C1, the nozzle N3 fills the first drop of ink into the cell C3, and the nozzle N4 fills the first drop of ink into the cell C4.

[0121] Further, as shown in FIG. 22B, when the nozzle N1 is at a distance m times (m is an integer) the search interval from the search start position, the nozzle N1 fills the first droplet into the cell C2. In this way, by appropriately shifting the position of the nozzle N1 by an integer multiple of the search interval that is neither the nozzle pitch nor the cell pitch, the ink can be landed at the center of the cell. Note that the position of the nozzle N1 may be moved by an integer multiple of the nozzle pitch or the cell pitch.

[0122] FIG. 23 is a flowchart showing a process of generating print control data when a plurality of ink droplets are supplied to the same cell. First, the generation unit 21b of the print control device 20 receives a designation of a method of supplying a plurality of ink droplets from the user (step S71).

[0123] Examples of the method of supplying a plurality of ink droplets include a method of supplying ink to each cell in order from the nozzles capable of supplying ink, and a method of repeatedly supplying one drop of ink to all cells until the required number of droplets is reached. In addition to receiving the designation of the ink supply method from the user, the designation of the ink supply method may be received and stored in advance by the user, and the information may be read out at this timing.

[0124] As a method of supplying a plurality of ink droplets, when a method of supplying ink to each cell in order from a nozzle capable of supplying ink is specified, the generation unit 21b executes a process of searching for nozzles that can be used to eject ink to the landing areas in each cell shown in FIG. 14 (step S72), and then ends the generation process of this print control data.

[0125] In step S71, as a method of supplying a plurality of ink droplets, when a method of repeatedly supplying one drop of ink to all cells until the required number of droplets is reached is specified, the generation unit 21b obtains the total number of overprints from the number of ink droplets filled in one print in the cell (step S73). Specifically, the generation unit 21b calculates the number of overprint times by dividing the number of ink droplets to be filled in each cell by the number of ink droplets filled in one print in the cell.

[0126] Next, the generation unit 21b separates the print data into a plurality of pages so that the number of ink droplets to be filled in each cell becomes the total of the number of droplets for each overprint (step S74).

[0127] Thereafter, the generation unit 21b repeats the processes of steps S76 and S77 for the number of overprints (step S75).

[0128] That is, the generation unit 21b individually sets the search start position, the search end position, and the search interval when searching for nozzles that can eject ink to the landing areas in each cell by moving the head for each overprint (step S76).

[0129] Then, the generation unit 21b executes a process of searching for nozzles that can be used to eject ink to the landing areas in each cell shown in FIG. 14 (step S77). After executing the processes of steps S76 and S77 for the number of overprints, the generation process of this print control data is ended.

[0130] In this way, in step S76, by individually setting the search start position, the search end position, and the search interval, it is possible to extract nozzles such that the nozzles used for ink ejection differ between overcoats for each cell. As a result, the deviation in ejection volume for each nozzle can be offset, and unevenness in display brightness can be reduced.

[0131] FIGS. 24A to 24C are diagrams showing a method of supplying ink to each cell in order from the nozzles capable of supplying the ink described in step S72 of FIG. 23. The display panel 12 has rectangular cells 72 and rectangular landing areas 73 that are areas within the cells 72 that allow ink to land. In this example, three drops of ink are made to land on the landing area 73 in each cell.

[0132] For example, in this method, as shown in FIG. 24A, when the nozzle N1 is at a distance of n times (n is an integer) the search interval from the search start position, the nozzles N2 and N3 fill the landing area of the cell C1 with the first and second drops of ink, and the nozzle N4 fills the landing area of the cell C2 with the first drop of ink.

[0133] Also, as shown in FIG. 24B, when the nozzle N1 is at a distance of m times (m is an integer) the search interval from the search start position, the nozzle N2 fills the landing area of the cell C1 with the third drop of ink, and the nozzle N3 fills the landing area of the cell C2 with the second drop of ink. Further, as shown in FIG. 24C, when the nozzle N1 is at a distance of l times (l is an integer) the search interval from the search start position, the nozzle N2 fills the landing area of the cell C2 with the third drop of ink.

[0134] In this way, in this method, at each search position, ink is supplied to the landing area of each cell in order from the nozzles capable of supplying ink to the landing area of each cell.

[0135] Figures 25A to 25D are diagrams showing another example of a method of supplying ink to each cell in order from a nozzle capable of supplying ink. The display panel 12 has square cells 13 and square landing areas 14 which are areas allowing the landing of ink within the cells 13. In this example, three drops of ink 15 are landed on each landing area 14.

[0136] For example, in this method, as shown in FIG. 25A, when the nozzle N1 is at a distance n times the search interval from the search start position (n is an integer), the nozzles N3 and N4 fill the landing areas of the cells C1 and C2 with the first drop of ink respectively.

[0137] Also, as shown in FIG. 25B, when the nozzle N1 is at a distance m times the search interval from the search start position (m is an integer), the nozzle N3 fills the landing area of the cell C2 with the second drop of ink, and the nozzle N4 fills the landing area of the cell C3 with the first drop of ink.

[0138] Also, as shown in FIG. 25C, when the nozzle N1 is at a distance l times the search interval from the search start position (l is an integer), the nozzle N2 fills the landing area of the cell C1 with the second drop of ink, the nozzle N3 fills the landing area of the cell C3 with the second drop of ink, and the nozzle N4 fills the landing area of the cell C4 with the first drop of ink.

[0139] Furthermore, as shown in FIG. 25D, when the nozzle N1 is at a distance о times the search interval from the search start position (о is an integer), the nozzle N1 fills the landing area of the cell C1 with the third drop of ink, the nozzle N2 fills the landing area of the cell C2 with the third drop of ink, the nozzle N3 fills the landing area of the cell C4 with the second drop of ink, and the nozzle N4 fills the landing area of the cell C5 with the first drop of ink.

[0140] In this way, at each search position, ink is supplied to the landing areas of each cell in order from the nozzles capable of supplying ink to the landing areas of each cell.

[0141] Figures 26A to 26F are diagrams showing a method of repeatedly supplying one drop of ink to each cell until the required number of droplets described in steps S73 to S78 of FIG. 23 is reached. The display panel 12 has square cells 13 and square landing areas 14 which are areas within the cells 13 that allow the ink 15 to land.

[0142] In this example, three drops of ink 15 are made to land on each landing area 14. In this case, the ink is made to land three times on the landing areas within the same cell, but as described in step S76 of FIG. 23, it is assumed that the search start position is changed each time.

[0143] For example, in this method, as shown in FIG. 26A, when the nozzle N1 is at a distance that is n times (n is an integer) the search interval from the search start position, the nozzles N3 and N4 fill the landing areas of cells C2 and C3 with the first drop of ink respectively.

[0144] Also, as shown in FIG. 26B, when the nozzle N1 is at a distance that is m times (m is an integer) the search interval from the search start position, the nozzle N1 fills the landing area of cell C1 with the first drop of ink, the nozzle N3 fills the landing area of cell C4 with the first drop of ink, and the nozzle N4 fills the landing area of cell C5 with the first drop of ink. Thus, one drop of ink is supplied to each cell 12.

[0145] Next, as shown in FIG. 26C, when the nozzle N1 is at a distance that is l times (l is an integer) the search interval from the search start position, the nozzle N2 fills the landing area of cell C1 with the second drop of ink, the nozzle N3 fills the landing area of cell C3 with the second drop of ink, and the nozzle N4 fills the landing area of cell C4 with the second drop of ink.

[0146] Also, as shown in FIG. 26D, when the nozzle N1 is at a distance that is о times (о is an integer) the search interval from the search start position, the nozzle N2 fills the landing area of cell C2 with the second drop of ink, and the nozzle N4 fills the landing area of cell C5 with the second drop of ink. Thus, two drops of ink are supplied to each cell 12.

[0147] Also, as shown in FIG. 26E, when the nozzle N1 is at a distance p times the search interval from the search start position, the nozzle N1 fills the landing area of the cell C1 with the third drop of ink, the nozzle N2 fills the landing area of the cell C2 with the third drop of ink, the nozzle N3 fills the landing area of the cell C4 with the third drop of ink, and the nozzle N4 fills the landing area of the cell C5 with the third drop of ink.

[0148] Furthermore, as shown in FIG. 26F, when the nozzle N1 is at a distance q times the search interval from the search start position, the nozzle N2 fills the landing area of the cell C3 with the third drop of ink. As a result, three drops of ink are supplied to each cell 12.

[0149] In this way, by repeating the supply of one drop of ink to all cells until the required number of droplets is reached, appropriate ink overprinting can be performed.

[0150] (Embodiment 2) The configurations of the printing apparatus 1 and the print control apparatus 20 in Embodiment 2 are substantially the same as those shown in FIGS. 6 and 7. Hereinafter, functions different from those of each part described in Embodiment 1 will be described.

[0151] FIG. 27 is a flowchart showing the printing method in Embodiment 2. First, the calculation unit 21a of the print control apparatus 20 calculates the resolution in the printing scan direction and the nozzle direction perpendicular to the printing scan direction (step S81). Then, the generation unit 21b generates print data including information on pixels that eject ink (step S82).

[0152] Subsequently, the detection unit 21c executes a landing inspection for actually ejecting ink from the nozzle and detecting the ejection accuracy of the nozzle from the landing position (step S83). Then, based on the result of the landing inspection, the nozzle control unit 21d selects usable nozzles whose landing deviation amount is within the allowable range (step S84).

[0153] After that, the calculation unit 21a generates a divided image obtained by dividing the print data generated in step S82 as a print image, and generates replacement data indicating that non-ejecting nozzles that are unusable with the nozzles selected in step S84 are to be replaced (step S85). Then, the nozzle control unit 21d refers to the divided image and the replacement data, and executes printing by ejecting ink from the nozzles (step S86).

[0154] Note that since the process of selecting usable nozzles in step S84 is partially different from the process of selecting usable nozzles shown in FIG. 12, the selection process in step S84 will be described with reference to FIG. 28.

[0155] FIG. 28 is a flowchart showing a process of selecting usable nozzles based on the result of the landing inspection shown in step S83 of FIG. 27. The processes of steps S91 to S94 and the process of step S96 in FIG. 28 are the same as the processes of steps S11 to S15 in FIG. 12, respectively.

[0156] However, in step S95 of FIG. 28, the detection unit 21c sets, in addition to the non-ejecting nozzles set in step S94, nozzles whose offset from the center of the landing target position in the nozzle direction exceeds a threshold value as non-ejecting nozzles. For example, the detection unit 21c sets nozzles whose offset calculated by the above-mentioned formula (3) is 1.73 μm or more to non-ejecting.

[0157] FIGS. 29A and 29B are diagrams showing a method of determining the resolution in the print scanning direction and the nozzle direction shown in step S81 of FIG. 27. As shown in FIG. 29A, the head 10 has a plurality of nozzle holes 11, and ink is ejected from the nozzle holes 11. Four nozzles N1 to N4 are formed in the head 10 at equal intervals. In the example of FIG. 29A, only one row of nozzles is shown in the print scanning direction, but in order to increase the resolution of the head, a plurality of nozzle rows shifted by 1 / n of the nozzle pitch (n is an integer) in the nozzle direction may be arranged at intervals in the print scanning direction.

[0158] The display panel 12 has square cells 13 and rectangular landing areas 83 which are areas allowing the ink to land within the cells 13. A plurality of inks are ejected from the nozzle holes 11 of the head 10 and applied to the landing areas 83. Note that the shape of the cells 13 may be other shapes such as a square, and the shape of the landing areas 83 may be other shapes such as a square.

[0159] As shown in FIG. 29B, when the size in the nozzle direction of the cells C1 to C5 is 20.0 μm, if the droplet diameter 20 of the ink is 12.0 μm and the landing escape which is a preliminary width for preventing the ink from protruding from the cells C1 to C5 is 2.0 μm, the size in the nozzle direction of the landing area for landing the ink is 4.0 μm according to the formula: size in the nozzle direction of the landing area = cell size - droplet diameter - landing escape × 2.

[0160] Also, since the resolution of the nozzles in the nozzle direction is 300 dpi, it is 84.667 μm. Here, the resolution of the nozzles is equal to the interval between the nozzles in the direction orthogonal to the printing scanning direction.

[0161] In this case, the calculation unit 21a rounds up the fractional part of the quotient obtained by dividing the interval between the nozzles in the nozzle direction by the length in the nozzle direction of the landing area within each cell, and calculates the resolution magnification. In the example of FIG. 29B, the calculation unit 21a rounds up the fractional part of 84.667÷4.0 = 21.667 and calculates the value of the resolution magnification as 22.

[0162] Then, the calculation unit 21a calculates the resolution required for printing by multiplying the resolution of the nozzles by the resolution magnification. In the example of FIG. 29B, the calculation unit 21a calculates the resolution required for printing as 300×22 = 6,600 dpi.

[0163] Furthermore, the calculation unit 21a calculates the resolution required for printing by dividing the resolution of the nozzles by the resolution magnification. In the example of FIG. 29B, the calculation unit 21a calculates the resolution required for printing as 84.667 μm ÷ 22 = 3.848 μm.

[0164] Since the length of the landing area in the nozzle direction is 4.0 μm and the resolution required for printing is 3.848 μm, which is smaller than 4.0 μm, the printing control device 20 can appropriately land the ink on the landing area.

[0165] In this way, the calculation unit 21a calculates the resolution in the nozzle direction required for discharging the ink onto the landing area based on the interval in the nozzle direction orthogonal to the printing scan direction of the plurality of nozzles and the length in the nozzle direction of the landing area in each cell. Thereafter, the nozzle control unit 21d performs a process of moving the head in the nozzle direction based on the resolution in the nozzle direction.

[0166] Also, as shown in FIG. 29B, when the size of cells C1 to C5 in the printing scan direction is 20.0 μm, if the droplet diameter of the ink is 12.0 μm and the landing margin, which is a preliminary width to prevent the ink from overflowing from cells C1 to C5, is 1.0 μm, then the size of the landing area for landing the ink in the printing scan direction is 6.0 μm according to the formula landing possible area = cell size - droplet diameter - landing margin × 2.

[0167] Also, since the resolution of the nozzles in the printing scan direction is 1,200 dpi, it is 21.167 μm.

[0168] In this case, the calculation unit 21a rounds up the fractional part of the quotient obtained by dividing the interval in the printing scan direction of the nozzles by the length in the printing scan direction of the landing area in each cell to calculate the resolution magnification. In the example of FIG. 29B, the calculation unit 21a rounds up the fractional part of 21.167 ÷ 6.0 = 3.527 and calculates the value of the resolution magnification as 4.

[0169] Then, the calculation unit 21a calculates the resolution required for printing by multiplying the resolution of the nozzles by the resolution magnification. In the example of FIG. 29B, the calculation unit 21a calculates the resolution required for printing as 1,200 × 4 = 4,800 dpi.

[0170] Furthermore, the calculation unit 21a calculates the resolution required for printing by dividing the resolution of the nozzles by the resolution magnification. In the example of FIG. 29B, the calculation unit 21a calculates the resolution required for printing as 21.167 μm ÷ 4 = 5.292 μm.

[0171] Since the length of the landing area in the printing scanning direction is 6.0 μm and the resolution required for printing is 5.292 μm, which is smaller than 6.0 μm, the printing control device 20 can appropriately land the ink on the landing area.

[0172] FIG. 30 is a diagram showing a printed image in which information on cells that eject ink is registered. The calculation unit 21a calculates the resolution in the nozzle direction and the printing scanning direction required for printing by the method described with reference to FIG. 29B, and generates data of a printed image having that resolution.

[0173] FIG. 31 is a diagram for explaining a method of dividing a printed image into divided images. The divided images are a plurality of different images each constituted by a part of the printed image as shown in FIG. 30.

[0174] Specifically, when the resolution magnification in the nozzle direction is d, the i-th (i is an integer from 1 to d) divided image of the plurality of divided images is constituted by the (i + d × j)-th (j = 0, 1, ···, floor{(N - i) / d}) column of the printed image data having N columns. Here, floor(x) is the floor function and represents the largest integer less than or equal to x.

[0175] For example, in the example of FIG. 31, since the resolution magnification d in the nozzle direction is 22 and the number of columns N of the printed image data is 40, the first divided image (division 1) is composed of the first column and the 23rd column of the printed image data. Also, the second divided image (division 2) is composed of the second column and the 24th column of the printed image data. Also, the 22nd (division 22) divided image is composed of the 22nd column of the printed image data.

[0176] The nozzle control unit 21d sequentially refers to these multiple divided images and controls the ejection of ink from each nozzle. Thereby, printing can be easily performed with the resolution required for printing.

[0177] In addition, when the divided image indicates that there is no cell from which ink should be ejected, the nozzle control unit 21d may omit the printing process that refers to that divided image.

[0178] FIG. 32 is a diagram for explaining the replacement of non-ejecting nozzles described in step S85 of FIG. 27. In the example of FIG. 32, the nozzles with nozzle numbers 2, 3, and 4 are non-ejecting nozzles. In addition, in the fifth divided image (division 5) and the fourteenth divided image (division 14), since ink is ejected from the nozzle with nozzle number 1, there is no influence of the non-ejecting nozzles.

[0179] However, in the first divided image (division 1) and the tenth divided image (division 10), since the nozzle from which ink should be ejected is the non-ejecting nozzle with nozzle number 2, the nozzle control unit 21d moves the position of the head in the nozzle direction and controls to complement the non-ejecting nozzle with the normal nozzle with nozzle number 1 to eject ink. Thereby, printing can be performed even when there is a non-ejecting nozzle.

[0180] Furthermore, when the intervals between the nozzles and the cells are different, printing is performed while shifting the position of the head as follows. FIGS. 33A to 33D are diagrams showing the ink ejection method when the intervals between the nozzles and the cells are different.

[0181] In this case, as shown in FIG. 33A, the nozzle control unit 21d shifts the position of the head 1 until the position of the nozzle N1 reaches a distance that is n / d times the nozzle pitch, and causes the nozzle N1 to eject ink to the cell C1.

[0182] Next, as shown in FIG. 33B, the nozzle control unit 21d shifts the position of the head 1 until the position of the nozzle N1 reaches a distance that is m / d times the nozzle pitch, and causes the nozzle N1 to eject ink to the cell C2.

[0183] Furthermore, as shown in FIG. 33C, the nozzle control unit 21d shifts the position of the head 1 until the position of the nozzle N1 reaches a distance that is l / d times the nozzle pitch, and causes the nozzle N1 to eject ink to the cell C3.

[0184] After that, as shown in FIG. 33D, the nozzle control unit 21d shifts the position of the head 1 until the position of the nozzle N1 reaches a distance that is о / d times the nozzle pitch, and causes the nozzle N1 to eject ink to the cell C4.

[0185] Here, d is the resolution magnification in the nozzle direction, and n, m, l, о are calculated by (the pixel number - 1) where the nozzle N1 should eject ink.

[0186] For example, when ejecting ink to the columns 23, 5, 32, 14 of the divided image shown in FIG. 32, d is 22 which is the resolution magnification in the nozzle direction. Also, n = 5 - 1 = 4, m = 14 - 1 = 13, l = 23 - 1 = 22, о = 32 - 1 = 31.

[0187] In this case, assuming the nozzle pitch is 84.667 μm, the amounts of shifting the head position in FIGS. 33A to 33D are 84.667×4 / 22 = 15.394 μm, 84.667×13 / 22 = 50.031 μm, 84.667×22 / 22 = 84.667 μm, 84.667×31 / 22 = 119.304 μm, respectively.

[0188] In the examples of FIGS. 33A to 33D, the case where the amount of displacement of the head position gradually increases so that the head does not move frequently from side to side is described. That is, in FIG. 32, the case where the divided images are referred to in the order of the fifth divided image, the fourteenth divided image, the first divided image, and the tenth divided image and printing is performed is described.

[0189] In addition, when there is a non-ejecting nozzle that cannot be used, or when the distance between the nozzle and the cell is different, it becomes difficult to land the ink on the landing area in each cell. However, as described above, the generation unit 21b of the printing control device 20 extracts, for each position of the head when the ink is ejected, the nozzles capable of ejecting the ink into the area in each cell among the plurality of nozzles based on the landing position of the ink when the head having a plurality of nozzles in the nozzle direction is relatively moved with respect to the work and ejected, generates the data of the print image indicating the extracted nozzles, and the nozzle control unit 21d moves the head in the nozzle direction and selects the nozzles for ejecting the ink based on the data of the print image to control the ejection of the ink.

[0190] Here, when it is necessary to land a plurality of drops of ink on the landing area in one cell, the generation unit 21b extracts a plurality of nozzles capable of ejecting the ink into the area in one cell and generates the data of the print image including the data indicating the extracted nozzles.

[0191] In this way, by shifting the head in the nozzle direction and extracting the nozzles capable of ejecting the ink into the area in one cell or a plurality of cells, appropriate printing can be performed even when there is a non-ejecting nozzle that cannot be used or when the distance between the nozzle and the cell is different.

[0192] (Embodiment 3) The configurations of the printing apparatus 1 and the printing control device 20 in Embodiment 2 are substantially the same as those shown in FIGS. 6 and 7. Hereinafter, functions different from those of each part described in Embodiments 1 and 2 will be described.

[0193] In Embodiment 3, a function of ejecting a plurality of ink droplets from one nozzle into one cell in one scan of the print scan direction by the head will be described.

[0194] FIG. 34 is a diagram showing the relationship between the size in the print scan direction of the landing areas 14a and 14b and the number of times the ink 15 can be ejected. In the example of FIG. 34, the case is shown where the basic resolution in the print scan direction of the nozzle described with reference to FIGS. 9B and 29B is 5 μm, the resolution magnification in the print scan direction of the cell is 8, the resolution in the print scan direction of the nozzle is 0.625 μm, and the diameter of the ink 15 is 1.25 μm. Here, the resolution in the print scan direction of the nozzle is obtained by dividing the basic resolution by the resolution magnification.

[0195] That is, in this example, the ink 15 can be landed on the landing area at intervals of 5 μm from one nozzle, and the landing positions of the ink 15 landed at intervals of 5 μm can be shifted in the print scan direction by 0.625 μm each.

[0196] In this case, in the landing area 14a with a small size in the print scan direction, even if the ink is landed at intervals of 5 μm and the landing position is shifted, the number of ink droplets of the ink 15 that can be landed on the landing area 14a is one. On the other hand, in the landing area 14b with a large size in the print scan direction, by landing at the shortest interval of 5 μm and shifting the landing position, the number of ink droplets of the ink 15 that can be landed on the landing area 14a becomes two.

[0197] Thus, when it is necessary to fill a plurality of ink droplets 15 in one landing area 14b, the number of times the ink 15 can be filled from one nozzle into one landing area is calculated, and the ink 15 is ejected from one nozzle as much as possible until the required number of droplets is reached.

[0198] Thus, for example, when it is necessary to fill three drops in the landing areas 14a and 14b, in the landing area 14a, the head 10 needs to perform three scans, while in the landing area 14b, the head 10 only needs to perform two scans. Therefore, the printing tact can be shortened. This process will be described in more detail below.

[0199] FIG. 35 is a diagram showing the relationship among the size of the landing area, the number of divided areas, and the number of ejectable times. The size of the landing area is the size of the landing area in the printing scan direction. The number of divided areas is the number obtained by the following formula.

[0200] (Number of divided areas) = floor{(Size of the landing area in the printing scan direction) / (Resolution of the nozzle in the printing scan direction)}

[0201] Here, the resolution of the nozzle in the printing scan direction corresponds to the resolution required for printing described with reference to FIGS. 9B and 29B.

[0202] Also, the number of ejectable times is the number of times ink can be ejected from one nozzle to one landing area by one scan of the head 10 in the printing scan direction. The number of ejectable times is obtained by the following formula.

[0203] (Number of ejectable times) = ceil{(Number of divided areas) / (Resolution magnification in the printing scan direction)} Here, ceil(x) is the ceiling function and represents the smallest integer greater than or equal to x.

[0204] In this way, the number of times ink can be ejected to the landing area is calculated from the size of the landing area in the printing scan direction, the resolution of the nozzle in the printing scan direction, and the resolution magnification in the printing scan direction.

[0205] In the example of FIG. 35, when the size of the landing area in the printing scan direction is 1 to 5 μm, the number of times ink can be ejected onto the landing area is 1. When the size of the landing area in the printing scan direction is 6 to 10 μm, the number of times ink can be ejected onto the landing area is 2. When the size of the landing area in the printing scan direction is 11 to 14 μm, the number of times ink can be ejected onto the landing area is 3.

[0206] FIG. 36 is a flowchart showing the search position and nozzle selection process performed in the printing times minimization mode. It differs from the process described in FIG. 18D in that a nozzle capable of ejecting ink a plurality of times in one scan in the printing scan direction is adopted for one landing area.

[0207] In step S41 shown in FIG. 18A, when the printing times minimization mode is specified, as shown in FIG. 36, the generation unit 21b sequentially selects each cell (step S101). Then, the generation unit 21b calculates the number of times the nozzle can eject ink onto the selected cell by the method described with reference to FIG. 35 (step S102). Thereafter, each available nozzle extracted in step S21 of FIG. 14 is sequentially selected (step S103).

[0208] Then, the generation unit 21b refers to the nozzle number data shown in FIG. 17, sequentially selects from the positions with a larger number of nozzles among the positions of the heads indicated by the search numbers, and extracts the nozzles capable of ejecting ink at the selected positions with reference to the holding data shown in FIG. 16 (step S104).

[0209] Here, in step S104, the generation unit 21b extracts the nozzles that eject the number of droplets required for the cell. However, referring to the number of ejectable times calculated in step S102, when one nozzle can eject ink a plurality of times for the cell, the count value is increased by that number of times, and the nozzles that eject ink are extracted until the count value reaches the number of droplets required for the cell.

[0210] If the process of step S104 has not been completed for each nozzle, the process returns to step S103 and the next nozzle is selected (step S105). If the process of step S104 has been completed for each nozzle, the generation unit 21b determines whether the process from step S102 to step S105 has been completed for each cell (step S106).

[0211] If the process from step S102 to step S105 has not been completed for each cell, the process returns to step S101 and the next cell is selected. If the process from step S102 to step S105 has been completed for each cell, this search position and nozzle selection process ends.

[0212] Here, the search position and nozzle selection process performed in the printing times minimization mode has been described as an example. Similarly, for the search position and nozzle selection process performed in the registration error minimization mode shown in FIG. 18C and the volume error minimization mode shown in FIG. 18E, nozzles capable of discharging a plurality of drops of ink into one cell in one scan of the head in the printing scan direction can be extracted, and a function of discharging ink from such nozzles can be realized.

[0213] (Embodiment 4) The configurations of the printing apparatus 1 and the printing control apparatus 20 in Embodiment 4 are substantially the same as those shown in FIGS. 6 and 7. Hereinafter, functions different from those of each part described in Embodiments 1 to 3 will be described.

[0214] In Embodiment 4, a function of landing the required number of droplets of ink in a cell even when there is a tendency for the traveling direction to bend on the stage 30 shown in FIG. 6 will be described.

[0215] FIG. 37 is a diagram showing an example of the turning of the stage 30 in the traveling direction. FIG. 37 shows a head 10 provided with nozzles N1, N2, ···, Nm (m is a positive integer) and a display panel 12 which is a workpiece placed on the stage 30. Although it is desirable for the stage 30 to move straight in the printing scanning direction, in the example of FIG. 37, it turns and moves in the direction of the arrow.

[0216] In this case, based on the information regarding the turning of the stage 30 in the traveling direction, the nozzles for discharging ink to each cell are selected. For example, in the example of FIG. 37, nozzle N1 is selected for the cell 13 in the first region 12a of the display panel 12, nozzle N2 is selected for the cell 13 in the second region 12b, and nozzle N1 is selected for the cell 13 in the third region 12c. Thereby, ink can be appropriately landed on each cell 13.

[0217] Note that the turning manner of the stage 30 in the traveling direction is not limited to that shown in FIG. 37, and various turning manners such as turning to the left or meandering left and right are conceivable, but the technology of Embodiment 4 can cope with any turning manner.

[0218] Hereinafter, this function will be described in more detail. First, the cell grouping process for reducing the calculation amount of the processor will be described. FIG. 38 is a flowchart showing a printing method including the cell grouping process in Embodiment 4.

[0219] First, the calculation unit 21a of the print control device 20 calculates the resolution in the printing scanning direction (step S111). Then, the generation unit 21b generates print data in which the positions of the regions in each cell for discharging ink are registered as vector data (step S112).

[0220] Subsequently, the detection unit 21c executes a landing inspection for actually discharging ink from the nozzle and detecting the discharge accuracy of the nozzle from the landing position (step S113). This landing inspection will be described in more detail later with reference to FIG. 40.

[0221] Then, based on the results of the landing inspection, the detection unit 21c executes a cell grouping process that groups a plurality of cells into one group.

[0222] FIG. 39 is a diagram showing an example of a cell group obtained as a result of the cell grouping process. FIG. 39 shows a plurality of cells and the landing regions A1 to An, B1 to Bn, C1 to Cn, D1 to Dn of each cell. The detection unit 21c includes cells that satisfy the following three conditions in the same cell group.

[0223] (1) The center coordinates of the cells in the nozzle direction are the same (2) The size of the landing region (lengths in the printing scan direction and the nozzle direction) is the same (3) The number of ink droplets to be landed on the landing region is the same

[0224] FIG. 39 shows four cell groups A to D generated in this way. In this way, a plurality of cells are grouped as cell groups, and the landing regions in each cell arranged in the printing scan direction included in the cell group are regarded as one landing region, and an operation is performed to extract the nozzles capable of discharging ink onto the one landing region in units of cell groups, thereby reducing the calculation amount of the processor.

[0225] Note that the positions of the cell groups in the printing scan direction may be shifted or aligned as shown in FIG. 39. Even if the positions of the cell groups are shifted, by adjusting the ink ejection timing, the ink can be appropriately landed on the landing region.

[0226] Subsequently, based on the results of the landing inspection and the results of the cell grouping process, the nozzle control unit 21d selects usable nozzles whose landing deviation amount is within the allowable range (step S115).

[0227] After that, the nozzle control unit 21d searches for nozzles capable of discharging ink to the landing areas of cells for each cell group from among the selected nozzles, and generates nozzle data including the data of the searched nozzles (step S116). Then, the nozzle control unit 21d executes printing by referring to the nozzle data and discharging ink to the nozzles (step S117).

[0228] When executing printing, the nozzle control unit 21d discharges ink to the nozzles with a shifted timing based on the information on the positions in the printing scanning direction of the landing areas of the respective cells included in the cell group.

[0229] FIG. 40 is a flowchart of the landing inspection in step S113 of FIG. 38. First, the detection unit 21c discharges ink from the nozzles onto the landing inspection substrate and prints a predetermined landing pattern on the landing inspection substrate (step S121).

[0230] Next, the detection unit 21c observes the printed landing pattern with a camera or the like (step S122). FIG. 41 is a diagram schematically showing the observed landing pattern. The arrow indicates the moving direction of the stage 30. When the stage 30 moves while curving, the landing pattern also curves accordingly.

[0231] After that, the detection unit 21c compares the predetermined landing pattern with the actually printed landing pattern, and generates a correction table in which the information on the deviation amount of each landing position is registered. The deviation amount of each landing position includes the deviation amount due to the curve in the traveling direction of the stage 30.

[0232] The nozzle control unit 21d refers to this correction table and extracts nozzles capable of discharging ink to the landing areas of the respective cells when the landing position is shifted by the amount registered in the correction table.

[0233] As a result, even when the traveling direction of the stage 30 is bent and a deviation occurs in the landing position of the ink when the stage 30 is moved relative to the head, it is possible to extract nozzles that can land the ink on the landing area of each cell. Regarding the deviation of the landing position in the printing scanning direction, the nozzle control unit 21d corrects it by changing the ejection timing of the ink.

[0234] Next, the cell group division process described with reference to FIG. 39 will be described. FIG. 42 is a diagram for explaining the stage traveling bend margin. FIG. 42 shows the cell 13 and the landing area 14. Here, the width of the landing area 14 is A.

[0235] The detection unit 21c sets stage traveling bend margins each having a width of B at the left end and the right end inside the landing area 14. Then, the detection unit 21c sets a region having a width of C, which is obtained by removing the region corresponding to the stage traveling bend margin from the landing area 14, as a new landing area.

[0236] After that, the detection unit 21c executes a process of grouping a plurality of cells into cell groups based on the three conditions described above. At this time, when the deviation amount of the ink landing position is larger than the width B corresponding to the stage traveling bend margin, the detection unit 21c divides the cell group.

[0237] FIG. 43 is a diagram for explaining the division of the cell group. FIG. 43 shows a graph indicating the relationship between the deviation amount of the landing position in the nozzle direction and the stage traveling bend margin. The thick solid line in this graph indicates the deviation amount of the landing position in the nozzle direction at each position in the printing scanning direction. The width of the stage traveling bend margin corresponds to the width B shown in FIG. 42.

[0238] Further, FIG. 43 shows the division results of cell groups A to D. As shown in FIG. 43, the detection unit 21c divides the cell groups A to D into a plurality of cell groups at positions P1 and P2 in the printing scan direction where the landing deviation amount in the nozzle direction exceeds the stage travel bending margin.

[0239] In the example of FIG. 43, the detection unit 21c divides cell group A into a cell group composed of cells A1 and A2, a cell group composed of cells A3, A4, and A5, and a cell group composed of cells A5 and A7. Similarly for cell groups B to D, the detection unit 21c divides them into three cell groups.

[0240] By extracting the nozzles capable of discharging ink for each cell group divided in this way, it is possible to correct the influence of stage travel bending more accurately and perform printing.

[0241] Note that the process of searching for the nozzles that can be used for discharging ink to the landing area in each cell is the same as that shown in FIG. 14. However, since there is a difference in the process of step S21, that process will be described below.

[0242] FIG. 44 is a flowchart showing the process of extracting available nozzles in step S21 of FIG. 14. The generation unit 21b of the print control device 20 sequentially selects the positions of the head 51 with respect to the workpiece 52 shown in FIG. 13A, for example, at a predetermined search interval from the search start position to the search end position (step S131).

[0243] Also, the generation unit 21b sequentially selects each cell group at each position of the head 51 (step S132).

[0244] Next, the generation unit 21b performs correction processing for the landing deviation amount including stage travel bending (step S133). Specifically, the generation unit 21b executes correction processing without shifting the ink discharge position by the amount of deviation based on the information on the amount of deviation of each landing position registered in the correction table generated in step S123 of FIG. 40.

[0245] After that, the generation unit 21b sequentially selects each nozzle for each position of the head 51 and each cell (step S134).

[0246] Then, the generation unit 21b determines whether there is a nozzle capable of discharging ink to the landing area of each cell from the position corrected in step S133. If there is such a nozzle, the cell number of the cell where the ink from the nozzle can land, the search number indicating the search position where the ink from the nozzle can land, the nozzle number of the nozzle, and the amount of deviation of the landing position from the center position of the landing area in the nozzle direction of the nozzle are held as holding data as shown in FIG. 16 (step S135).

[0247] After that, for each nozzle, if the process of step S135 has not ended, the process returns to step S134 and the next nozzle is selected (step S136). When the process of step S135 has ended for each nozzle, the process proceeds to step S137. Then, for each cell group, if the processes from step S133 to step S136 have not ended, the process returns to step S132 and the next cell group is selected (step S137).

[0248] For each cell group, when the processes from step S133 to step S136 have ended, the generation unit 21b detects the number of nozzles capable of discharging ink to the area within each cell group for each search position of the head 51, and holds the data as nozzle number data as shown in FIG. 17 (step S138).

[0249] Then, for each search position, if the processes from step S132 to step S138 have not ended, the process returns to step S131 and the next search position is selected (step S139). When the processes from step S132 to step S138 have ended for each search position, this extraction process ends.

[0250] In the above-described embodiment, the case where the cell and the landing area are rectangular has been shown. However, the shapes of the cell and the landing area are not limited to this.

[0251] Figures 45A to 45C are diagrams showing an example of the cell 13 and the landing area 14 having shapes other than rectangular.

[0252] Specifically, in Fig. 45A, the case where the cell 13 is circular and the landing area 14 is elliptical is shown. The reason why the landing area 14 is elliptical is that it reflects the difference in the error of the landing position between the printing scanning direction and the nozzle direction. Fig. 45B shows the case where the cell 13 and the landing area 14 are hexagonal. Fig. 45C shows the case where the cell 13 and the landing area 14 are oval.

[0253] Thus, the shape of the cell 13 may be other than rectangular, and the shape of the landing area 14 may be determined according to the shape of the cell 13. By determining the shape of the landing area 14 according to the shape of the cell 13, the area of the landing area 14 can be increased, and the nozzles capable of discharging ink to the landing area 14 can be easily extracted.

[0254] Figures 46A to 46D are diagrams for explaining the case of setting a landing area 14' having a rectangular shape for the cell 13 having a shape other than rectangular.

[0255] The cell 13 and the landing area 14 shown in Fig. 46A are the same as the cell 13 and the landing area 14 shown in Fig. 45A. When the shape of the landing area is made rectangular for easy definition, it is desirable to use a rectangle with the maximum size that is inscribed in the landing area 14, like the landing area 14' shown in Fig. 46A.

[0256] In addition, the cells 13 and the landing areas 14 shown in FIGS. 46B and 46C are the same as the cells 13 and the landing areas 14 shown in FIG. 45B. When making the shape of the landing area into a rectangle that is easy to define, it is desirable to use a rectangle with the maximum size that is inscribed in the landing area 14, like the landing area 14' shown in FIG. 46B or FIG. 46C.

[0257] In addition, the cells 13 and the landing areas 14 shown in FIG. 46D are the same as the cells 13 and the landing areas 14 shown in FIG. 45C. When making the shape of the landing area into a rectangle that is easy to define, it is desirable to use a rectangle with the maximum size that is inscribed in the landing area 14, like the landing area 14' shown in FIG. 46D.

[0258] By adopting the rectangular landing area 14' such as that shown in FIGS. 46A to 46D, the definition of the landing area 14' becomes easier, the area of the landing area 14' can be made relatively large, and nozzles capable of discharging ink into the landing area 14' can be easily extracted.

[0259] Note that in Embodiment 4, the function of landing the necessary number of ink droplets into the cell even when there is a tendency for the traveling direction to bend in the moving stage 30 has been described. However, the application range of the technology of Embodiment 4 is not limited to this.

[0260] Whether ink can be landed in the cell depends on the relative positional relationship between the stage 30 and the head 10. Therefore, when there is a traveling bend in the moving head 10, and when both the head 10 and the stage 30 move and there is a traveling bend in at least one of the head 10 and the stage 30, the same technology as that described in Embodiment 4 can be applied.

[0261] In addition, in Embodiment 4, the cell grouping process has been described. However, when a high-performance processor is used and there is no need to reduce the amount of calculation, the cell grouping process is not necessary, and the correction process for traveling bends may be performed for each cell.

[0262] Further, without performing the correction process for the running curvature of the stage 30, the head 10 is moved following the movement of the stage 30, so that the relative position between the stage 30 and the head 10 does not fluctuate, and printing may be performed by eliminating the influence of the running curvature of the stage 30.

[0263] (Embodiment 5) The configurations of the printing apparatus 1 and the printing control apparatus 20 in Embodiment 5 are substantially the same as those shown in FIGS. 6 and 7. Hereinafter, functions different from those of the respective parts described in Embodiments 1 to 4 will be described.

[0264] In Embodiment 5, when the head 10 moves in the nozzle direction, a function of landing the necessary number of ink droplets in the cell even when the attitude angle of the head changes due to the deviation of the transfer axis holding the head 10 will be described.

[0265] FIG. 47 is a conceptual diagram showing states in which the attitude angles of the head 10 are different. FIG. 47 shows a state in which the head 10 is at four different positions in the nozzle direction (the width direction of the workpiece 52). In this example, it is desirable that the attitude of the head 10 be parallel to the nozzle direction, but the head 47 is rotated along the curved arrow.

[0266] Further, FIG. 47 shows examples of the landing positions of the ink 15 ejected from the heads 10 having different attitude angles. The landing positions of the ink 15 may deviate from a line parallel to the nozzle direction due to differences in the individual characteristics of the nozzles with respect to the ejection of the ink and the influence of the different attitude angles of the head 10.

[0267] Therefore, the deviation of the landing position due to the difference in the individual characteristics of each nozzle and the deviation of the landing position due to the different attitude angles of the head 10 are detected, and the nozzles for ejecting ink into each cell are selected based on that information.

[0268] For example, the deviation of the landing position due to different attitude angles of the head 10 is evaluated by approximating the actual landing position with a straight line L, and the deviation of the landing position due to differences in the individual characteristics of each nozzle is evaluated by the deviation from that straight line L. By selecting nozzles based on such evaluation results, ink can be appropriately landed on each cell.

[0269] The following further specifically describes this function. First, the flowchart showing the printing method in Embodiment 5 is the same as that shown in FIG. 38. Also, it is the same that the landing inspection shown in step S113 of FIG. 38 is performed according to the procedure shown in FIG. 40, but in Embodiment 5, the point where the influence of the deviation of the transfer axis for transferring the head 10 is observed is different from the process described in FIG. 40. This will be described in detail below.

[0270] FIG. 48 is a diagram for explaining the process of the landing inspection in Embodiment 5. First, the detection unit 21c causes the nozzles to eject ink onto the landing inspection substrate 41 and prints a predetermined landing pattern on the landing inspection substrate 41. At this time, the detection unit 21c performs printing while moving the head 10 a predetermined number of times along the transfer axis.

[0271] Next, the detection unit 21c observes the printed landing pattern with a camera or the like. FIG. 48 schematically shows the actually observed landing pattern. In this example, the landing pattern that should linearly extend in the nozzle direction is curved.

[0272] Thereafter, the detection unit 21c compares the predetermined landing pattern with the actually printed landing pattern and generates a correction table registering information on the deviation amount of each landing position.

[0273] Specifically, as shown in FIGS. 47 and 48, the detection unit 21c approximates the ink 15 landed at each position of the nozzle 10 with straight lines L (y = ax + b, y = cx + d, y = ex + f, y = gx + h), and further calculates the deviation amount of the actual landing position from the straight line L.

[0274] Then, the detection unit 21c registers, in the correction table, the amount of deviation between the straight line L and a straight line parallel to the nozzle direction as the amount of deviation of the landing position due to different attitude angles of the head 10, and also registers, in the correction table, the amount of deviation of the actual landing position from the straight line L as the amount of deviation of the landing position due to differences in the individual characteristics of each nozzle.

[0275] The nozzle control unit 21d refers to this correction data and extracts, when the landing position is shifted by the amount registered in the correction table, the nozzles capable of discharging ink to the landing area of each cell. Thereby, even when the attitude angle is different at the position of the head 10, it is possible to extract the nozzles capable of landing ink on the landing area of each cell. Regarding the deviation of the landing position in the printing scanning direction, the nozzle control unit 21d corrects it by changing the ink discharge timing.

[0276] Also, the process of searching for the nozzles that can be used to discharge ink to the landing area within each cell is the same as that shown in FIG. 14. However, since there is a difference in the process of step S21, that process will be described below.

[0277] FIG. 49 is a flowchart showing the process of extracting available nozzles in step S21 of FIG. 14. The generation unit 21b of the printing control device 20 sequentially selects, at a predetermined search interval from the search start position to the search end position, the positions of the head 51 with respect to the workpiece 52 shown in FIG. 13A, for example (step S141).

[0278] Next, the generation unit 21b performs correction processing for the landing deviation amount for each nozzle (step S142). Specifically, the generation unit 21b executes correction processing without shifting the ink discharge position by those deviation amounts, based on the information on the landing position deviation amount registered in the correction table, from the landing position deviation amount due to different attitude angles of the head 10 and the landing position deviation amount due to differences in the individual characteristics of each nozzle.

[0279] After that, the generation unit 21b sequentially selects each cell group (step S143). Further, the generation unit 21b sequentially selects each nozzle for each position of the head 10 and for each cell group (step S144).

[0280] Then, the generation unit 21b determines whether there is a nozzle capable of discharging ink to the landing area of each cell from the position corrected in step S142. If there is such a nozzle, the cell number of the cell where the ink from the nozzle can land, the search number indicating the search position where the ink from the nozzle can land, the nozzle number of the nozzle, and the information on the deviation amount of the landing position from the center position of the landing area in the nozzle direction of the nozzle are held as holding data as shown in FIG. 16 (step S145).

[0281] After that, for each nozzle, if the process of step S145 has not ended, the process returns to step S144 and the next nozzle is selected (step S146). When the process of step S145 has ended for each nozzle, the process proceeds to step S147. Then, for each cell group, if the processes from step S144 to step S146 have not ended, the process returns to step S143 and the next cell group is selected (step S147).

[0282] When the processes from step S144 to step S146 have ended for each cell group, the generation unit 21b detects the number of nozzles capable of discharging ink to the area within each cell group for each search position of the head 10, and holds the data as nozzle number data as shown in FIG. 17 (step S148).

[0283] Then, for each search position, if the processes from step S142 to step S148 have not ended, the process returns to step S141 and the next search position is selected (step S149). When the processes from step S142 to step S148 have ended for each search position, this extraction process ends.

[0284] Note that whether ink can land in a cell depends on the relative positional relationship between the stage 30 and the head 10. Therefore, when a change occurs in the posture of the moving head 10, and also when both the head 10 and the stage 30 move and a change occurs in the posture of at least one of the head 10 and the stage 30, a technique similar to the technique described in Embodiment 5 can be applied.

[0285] Further, in the example of FIG. 48, four sections of the heads 10 are shown. However, when ink lands between adjacent sections of the heads 10, the deviation amount of the landing position may be evaluated using a straight line having weighted average values of the slopes and intercepts of two straight lines corresponding to the adjacent sections of the heads 10 as the slope and intercept.

[0286] Also, when ink lands on the left side of the leftmost section, the deviation amount of the landing position may be evaluated using a straight line having the same slope and intercept as the slope and intercept of the straight line corresponding to the leftmost section.

[0287] Similarly, when ink lands on the right side of the rightmost section, the deviation amount of the landing position may be evaluated using a straight line having the same slope and intercept as the slope and intercept of the straight line corresponding to the rightmost section.

[0288] Although the above embodiments have been described, in the above embodiments, each component may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

[0289] Further, the general or specific aspects of the present invention may be realized by an apparatus, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM. Further, they may be realized by any combination of an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0290] In addition, forms obtained by applying various modifications that can be conceived by those skilled in the art to each embodiment, or forms realized by arbitrarily combining the components and functions in each embodiment without departing from the spirit of the present disclosure are also included in the present disclosure.

Industrial Applicability

[0291] The present disclosure can be used for a printing control device, a printing device, and a printing control method that can eject ink.

Explanation of Signs

[0292] 1 Printing device 2 Host PC 10 Head 11 Nozzle hole 12 Display panel 13 Cell 14 Landing area 15 Ink 20 Printing control device 21a Calculation unit 21b Generation unit 21c Detection unit 21d Nozzle control unit

Claims

1. A calculation unit that calculates the resolution in the printing scan direction required for ejecting ink onto the area based on the interval in the printing scan direction between a plurality of nozzles that eject ink and the length in the printing scan direction of the area within each cell that allows the ink to land; A nozzle control unit that controls the ejection timing of the ink from the plurality of nozzles in the printing scan direction based on the resolution; A printing control device comprising the same.

2. The printing control device according to Claim 1, wherein the calculation unit calculates a first resolution magnification obtained by rounding up the fractional part in the quotient obtained by dividing the interval in the printing scan direction by the length, and calculates the resolution in the printing scan direction by dividing the interval in the printing scan direction by the first resolution magnification.

3. Based on the landing position of the ink when ejecting the ink while relatively moving a head having the plurality of nozzles in a nozzle direction orthogonal to the printing scan direction with respect to a workpiece, for each position of the head when ejecting the ink, a generation unit that extracts nozzles capable of ejecting ink onto the area within each cell among the plurality of nozzles and generates first data indicating the extracted nozzles; The nozzle control unit moves the head in the nozzle direction, selects the nozzles that eject the ink based on the first data, and controls the ejection of the ink. The printing control device according to Claim 1 or 2.

4. The printing control device according to Claim 3, wherein the generation unit extracts a plurality of nozzles capable of ejecting ink onto the area within one cell and generates the first data including data indicating the extracted nozzles.

5. The printing control device according to Claim 3, wherein the nozzle control unit controls the ejection of the ink by referring to printing data in which the position of the area within each cell where the ink is ejected is registered as vector data.

6. When the generating unit discharges the ink at a plurality of positions of the head in the nozzle direction different from when the first data is generated, based on the landing positions of the ink, for each position of the head, it extracts nozzles capable of discharging ink to the regions within each cell among the plurality of nozzles, generates second data of the extracted nozzles, and when the nozzle control unit discharges the ink a plurality of times to a region within one cell, it selects the nozzles for discharging the ink based on the first data to control the discharge of the ink to the region within the one cell, and further selects the nozzles for discharging the ink based on the second data to control the discharge of the ink to the region within the one cell. The printing control apparatus according to claim 3.

7. When the generating unit discharges the ink a plurality of times to a region within one cell, it extracts a plurality of different nozzles capable of discharging ink to the region within the one cell among the plurality of nozzles, and generates the first data. The printing control apparatus according to claim 3.

8. The generating unit extracts a plurality of non - adjacent nozzles as the plurality of different nozzles. The printing control apparatus according to claim 7.

9. The generating unit selects, in order, from the combinations of the positions of the head and nozzles in which the amount of deviation from the target landing position of the ink in the region within each cell among the plurality of nozzles is small, and extracts the positions of the head and nozzles capable of discharging ink to the regions within each cell. The printing control apparatus according to claim 3.

10. When the generating unit moves the head in the nozzle direction, it detects the number of nozzles capable of discharging ink to the regions within each cell for each position of the head. When discharging the ink a plurality of times to a region within one cell, it selects, in order, from the positions of the head where the number of nozzles is large, and extracts the nozzles capable of discharging ink at the selected positions as the nozzles for discharging ink at the selected positions. The printing control apparatus according to claim 3.

11. The printing control device according to claim 3, wherein when the generating unit discharges the ink a plurality of times into an area within one cell, among the plurality of nozzles, the nozzle is extracted as a nozzle that discharges ink into the area within the one cell, and the sum of the volumes of the ink droplets landing in the area within the one cell is close to a target sum, or a nozzle capable of discharging ink with a volume closer to the expected value of the volume of the ink discharged from each nozzle.

12. The calculating unit calculates the resolution in the nozzle direction required for discharging ink into the area based on the interval in the nozzle direction orthogonal to the printing scanning direction of the plurality of nozzles and the length in the nozzle direction of the area within each cell, and the nozzle control unit moves the head having the nozzles in the nozzle direction based on the resolution in the nozzle direction. The printing control device according to claim 1 or 2.

13. The calculating unit calculates a second resolution magnification obtained by rounding up the fractional part after the decimal point in the quotient obtained by dividing the interval in the nozzle direction by the length in the nozzle direction, and calculates the resolution in the nozzle direction by dividing the interval in the nozzle direction by the second resolution magnification. The printing control device according to claim 12.

14. The calculating unit has a resolution corresponding to the resolution in the printing scanning direction and a resolution corresponding to the resolution in the nozzle direction, generates a plurality of different divided images each constituted by a part of a printing image indicating a cell that discharges the ink, and the nozzle control unit controls the discharging of the ink by sequentially referring to each of the plurality of divided images. The printing control device according to claim 12.

15. The calculating unit has a resolution corresponding to the resolution in the printing scanning direction and a resolution corresponding to the resolution in the nozzle direction, generates a plurality of different divided images each constituted by a part of a printing image indicating a cell that discharges the ink, the nozzle control unit controls the discharging of the ink by sequentially referring to the plurality of divided images, and when the second resolution magnification is d, the i-th (i is an integer of 1 or more and d or less) divided image of the plurality of divided images is constituted by the (i + d×j)-th (j = 0, 1,..., floor{(N - i) / d}) column of a printing image having N columns. The printing control device according to claim 13.

16. The printing control device according to claim 12, further comprising a detection unit that detects the ejection accuracy of the plurality of nozzles, wherein when there is a non-ejecting nozzle among the plurality of nozzles whose accuracy is lower than a reference, the nozzle control unit moves the head in the nozzle direction and selects a nozzle adjacent to the non-ejecting nozzle as a nozzle for ejecting the ink.

17. The printing control device according to claim 1, further comprising a generation unit that calculates the number of times the ink can be ejected from one nozzle to an area within one cell in one scan in the printing scan direction, wherein when the number of times is plural, the nozzle control unit controls the ejection timing of the ink so that the ink is ejected from the one nozzle to the area within the one cell a plurality of times in one scan in the printing scan direction.

18. The printing control device according to claim 1, further comprising a generation unit that extracts a plurality of different nozzles capable of ejecting ink to an area within one cell in one scan in the printing scan direction when the ink is ejected a plurality of times to the area within one cell in one scan in the printing scan direction, wherein the nozzle control unit controls the ejection timing of the ink from the plurality of nozzles extracted by the generation unit so that the ink is ejected to the area within the one cell in one scan in the printing scan direction.

19. The printing control device according to claim 1, further comprising a detection unit that sets a cell group in which cells having the same coordinates in the nozzle direction perpendicular to the printing scan direction, the size of the area within each cell, and the number of droplets of the ink to be landed on the area within each cell are grouped together, wherein the nozzle control unit regards the areas within each cell arranged in the printing scan direction included in the cell group as one area, extracts nozzles capable of ejecting the ink to the one area in units of the cell group, and controls the ejection timing of the ink from the extracted nozzles.

20. The printing control device according to claim 1, wherein the nozzle control unit extracts nozzles capable of ejecting the ink to the areas within each cell based on the amount of deviation of the landing position of the ink generated when the stage on which the work to be ejected with the ink is placed is relatively moved with respect to the head having the nozzles, and controls the ejection timing of the ink from the extracted nozzles.

21. The printing control device according to claim 1, wherein the nozzle control unit extracts nozzles capable of discharging the ink to regions in each cell based on the amount of deviation of the landing position of the ink generated when moving the head holding the head having the nozzles along the transfer axis, and controls the discharge timing of the ink from the extracted nozzles.

22. A printing apparatus comprising the printing control device according to claim 1.

23. A calculation step of calculating a resolution in the printing scan direction required for discharging the ink to the region based on an interval in the printing scan direction between a plurality of nozzles that discharge the ink and a length in the printing scan direction of a region in each cell that allows landing of the ink; A nozzle control step of controlling the discharge timing of the ink from the plurality of nozzles in the printing scan direction based on the resolution; A printing control method including the above steps.

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