JP7555007B2 - Inkjet printing apparatus and inkjet printing method - Google Patents

Description

This disclosure relates to an inkjet printing device and an inkjet printing method.

Conventionally, a method for forming an organic light-emitting layer of an organic EL (Electro Luminescence) display panel using an inkjet printing device is known. For example, one such method is to form a low molecular weight organic material or a high molecular weight organic material by a solvent coating method.

One typical method for forming an organic light-emitting layer by solvent coating is to use an inkjet printing device to eject droplets of ink (hereinafter also referred to as ink droplets) containing an organic light-emitting material onto the pixel region of a display substrate to form an organic light-emitting layer. The ejected ink droplets contain the organic light-emitting material and a solvent.

A typical inkjet printing device has an inkjet head with multiple nozzles, and ejects ink droplets from the nozzles while controlling the positional relationship between the nozzles and the substrate (workpiece), applying ink to the substrate.

For example, Patent Document 1 discloses an inkjet printing device that can form pixels with a specified line width by depositing ink droplets on a substrate so that they spread evenly in depressions called pixel regions.

When forming multiple pixels having a specified line width using the above-mentioned inkjet printing device, if there is a deviation in the landing position of the ink droplets, the required amount of ink droplets will not be applied to the target position, which is the pixel region itself, and the amount of ink in the pixel region itself will be insufficient. Furthermore, if ink droplets that should land in the pixel region itself are ejected into an adjacent pixel region adjacent to the pixel region itself, the amount of ink in the adjacent pixel region will be excessive.

If the amount of ink is too much or too little, the thickness of the light-emitting layer formed may differ between the pixel area and other pixel areas.

In addition, if the ink droplets ejected into the adjacent pixel region and the ink droplets ejected into the local pixel region are different luminescent inks, and one of these ink droplets lands between the local pixel region and the adjacent pixel region, the ink droplet will connect the two pixel regions. This can result in mixed-color emission in each pixel region.

Causes of deviations in the landing position of ink droplets include, for example, yawing (rotational deviation relative to the direction of travel of the display substrate) that occurs when the display substrate is swept, pitching, deviations in the nozzle arrangement (hereafter referred to as nozzle arrangement deviations), and deviations in the angle of the ink droplets ejected from the nozzle relative to the vertical direction (hereafter referred to as ejection angle deviations).

As a method for eliminating the above-mentioned deviation in the landing position, for example, Patent Document 2 discloses a method in which the timing of ejecting ink droplets from the nozzles of the inkjet head is changed based on the degree of yawing that occurs when the display substrate is swept.

More specifically, in the method of Patent Document 2, a scale and an encoder are provided on the left and right ends of a table (linear movement means) on which a display substrate is mounted, and the amount of yawing is calculated from the positions of each table end obtained by these, and the timing of ejecting ink droplets from all nozzles is corrected to an ejection timing that matches the amount of yawing.

Figure 13 (the same as Figure 4 in Patent Document 2) is a diagram that explains the positional deviation of the nozzle ejection hole due to yawing of the substrate, as disclosed in Patent Document 2. Figure 13 shows two scales (p-side scale indicated by p0...pn, and q-side scale indicated by q0...qn) attached to the left and right of the table that moves the base plate of the stage, and the position of the ink droplets ejected from the nozzle (nozzle ejection hole 69 in the figure) when the table passes directly under the inkjet head (head 67 in the figure).

At time _T0 , ink droplets are ejected from each of the nozzle ejection holes 69-1 to 69-n at position p0 and q0. Furthermore, at time Tn, ink droplets are ejected from each of the nozzle ejection holes 69-1 to 69-n at position pn and qn-1. In Figure 13, yawing is the phenomenon in which one increment (pulse) is delayed on the p-side scale. As shown in Figure 13, the amount of yawing (degree of yawing) can be obtained from the p-side scale and the q-side scale.

Figure 14 (the same as Figure 7 in Patent Document 2) is a diagram showing various components used to correct the timing at which ink droplets are ejected from an inkjet head, as disclosed in Patent Document 2.

The scale reading heads A65-1 and B65-2 respectively read the pulses (positions) of the p-side scale and the q-side scale shown in FIG. 13. The position encoders 91-1A and 91-2B respectively count the number of pulses read for each scale. The waveform generating unit 81 measures the time lag (a delay of one increment on the p-side scale) based on the number of pulses for each scale. Next, the waveform generating unit 81 generates the ejection on/off timing for all nozzles based on the time lag and the patterning data (printed image). Then, the waveform generating unit 81 controls the timing of ejecting ink droplets from each nozzle based on the ejection on/off timing. This makes it possible to correct the ejection timing based on yawing.

For example, Patent Document 3 discloses a method in which ink droplets are ejected from all nozzles onto a landing observation substrate having the same area as the display substrate, and the combined amount of yawing, pitching, nozzle arrangement deviation, and nozzle ejection angle deviation (hereinafter referred to as total landing deviation amount) is measured in advance from the deviation between the landing position and a reference position, and the print image is deformed (corrected) and printed based on the total landing deviation amount and the deviation amount in the negative direction (hereinafter referred to as total landing deviation correction amount).

Figure 15 (the same as Figure 16 in Patent Document 3) is a diagram showing the relationship between the print substrate and the inkjet head during the printing operation by moving the stage, as disclosed in Patent Document 3.

In FIG. 15, reference numeral 1 denotes a display substrate, reference numeral 1c denotes a pixel region, reference numeral 3 denotes an inkjet head, reference numeral 3a denotes a nozzle, and reference numeral 4 denotes a moving stage.

Also, (a) shown in the upper part of Figure 15 shows a state where there is no yawing of the moving stage 4 and no rotation of the inkjet head 3.

(b) shown in the lower part of Figure 15 shows a state in which the front half of the inkjet head 3 is not rotating, and the rear half of the inkjet head 3 is rotating. Furthermore, (b1) shows a state in which the moving stage 4 is rotating in the counterclockwise direction. (b2) shows a state in which the moving stage 4 is rotating in the clockwise direction. (b3) shows a state in which the moving stage 4 is rotating counterclockwise while sweeping and printing.

Figure 16 (the same as Figure 13 in Cited Document 3) is a diagram showing the assumed landing positions when droplets are ejected at a uniform pitch onto a landing observation substrate having the same area as the display substrate, using the printing operation shown in Figure 15(b) disclosed in Patent Document 3. As shown in Figure 16, the assumed landing positions of eight droplets (black circles in the figure) are shown in each pixel region 1c.

Figure 17 (the same as Figure 14 in Cited Document 3) is a diagram showing original image data created based on the assumed landing positions shown in Figure 16, which is disclosed in Patent Document 3. The original image data shown in Figure 17 is stored in the memory of the printing device. Based on the original image data, the printing device ejects ink from each nozzle of the inkjet head, corrects the overall landing deviation, and causes eight ink droplets to land within each pixel area. This makes it possible to reduce mixed color emission and uneven emission when the display is illuminated.

JP 2003-266669 A JP 2007-152215 A JP 2015-138693 A

However, in the method of Patent Document 2, because the ejection timing of all nozzles is corrected at the scale portion of the stage, if the first yawing observed at the scale portion differs from the second yawing on the display substrate on the stage, there is a problem that the landing position will be shifted by the difference between the first yawing and the second yawing. In recent years, display panels have become larger and more multi-paneled, and printing takt times have been shortened due to increased production volume. As a result, the difference between the first yawing and the second yawing tends to become larger due to reduced rigidity caused by the enlargement of the stage area and faster printing sweeps.

In addition, in Patent Document 3, the amount of correction for the total landing deviation based on the total landing deviation (the combined amount of yawing, pitching, nozzle position deviation, and ejection angle deviation) is reflected on the entire surface of the printed image, thereby making it possible to correct the deviation in the landing position.

The total landing deviation amount here is the sum of one-dimensional deviation (the combined amount of nozzle placement deviation and ejection angle deviation) that is not dependent on stage movement, and two-dimensional deviation (the combined amount of yawing and pitching) that occurs due to stage movement, but the one-dimensional deviation changes more frequently and to a greater extent over time than the two-dimensional deviation. This is because the accuracy fluctuations of a stage with a large mass change slowly depending solely on temperature, whereas the fluctuations in ejection angle deviation for droplets of a few pL (picoliters) depend on changes in ink concentration and the number of ejections. Correction of the total landing deviation amount, which is the sum of these different fluctuations, must be performed according to the fluctuations in the one-dimensional deviation, which are more frequent.

However, as the print image becomes larger, there is a problem in that the processing time increases in proportion to the size of the print image, such as the time required to reflect the total landing misalignment correction amount and the time required to write the original image data to memory. Also, as mentioned above, in recent years, display panels have become larger and more multi-panel, and print takt times have been shortened due to increased production volume, making it difficult to create a large print image and write it to image memory within the print takt time required to satisfy the required production volume.

The objective of one aspect of the present disclosure is to provide an inkjet printing device and inkjet printing method that can correct deviations in the landing positions of ink droplets while reducing processing time.

An inkjet printing device according to one aspect of the present disclosure is an inkjet printing device having a moving stage that moves a printing substrate, and an inkjet head that ejects ink droplets from a plurality of nozzles onto the printing substrate, the inkjet printing device having a printing original image holder that holds original image data indicating landing positions of the ink droplets on the printing substrate, a misalignment information holder that holds a two-dimensional misalignment correction amount used to correct a two-dimensional misalignment of the landing positions of the ink droplets for each nozzle and a one-dimensional misalignment correction amount used to correct a one-dimensional misalignment, a per-nozzle variable delay device that generates ejection on/off instruction information that changes the ejection timing of the ink droplets based on the original image data and the one-dimensional misalignment correction amount and the two-dimensional misalignment correction amount , and a drive signal selector that turns on/off the ejection of the ink droplets for each nozzle based on the ejection on/off instruction information, and calculates the one-dimensional misalignment correction amount and the two-dimensional misalignment correction amount based on the in-plane scanning direction misalignment amount of each nozzle.

An inkjet printing method according to one aspect of the present disclosure is an inkjet printing method performed using a moving stage that moves a print substrate and an inkjet head that ejects ink droplets from a plurality of nozzles onto the print substrate, the method storing, in separate memories, original image data indicating landing positions of the ink droplets on the print substrate, and a two-dimensional misalignment correction amount used to correct a two-dimensional misalignment of the landing positions of the ink droplets for each nozzle and a one-dimensional misalignment correction amount used to correct a one-dimensional misalignment, the method generating ejection on/off instruction information that changes an ejection timing of the ink droplets based on the original image data and the one-dimensional misalignment correction amount and the two-dimensional misalignment correction amount , turning on/off the ejection of the ink droplets for each nozzle based on the ejection on/off instruction information, and calculating the one-dimensional misalignment correction amount and the two-dimensional misalignment correction amount based on an in-plane scanning direction misalignment amount of each nozzle.

According to the present disclosure, it is possible to correct the deviation in the landing position of ink droplets while reducing processing time.

1 is a plan view of a display panel substrate according to a first embodiment of the present disclosure; AA cross-sectional view of FIG. BB cross-sectional view of FIG. 1C-C cross-sectional view FIG. 1 is a diagram showing a relationship between a pixel region and a print ejection dot grid according to the first embodiment of the present disclosure. FIG. 1 is a block diagram showing an inkjet printing apparatus according to a first embodiment of the present disclosure. FIG. 1 is a diagram showing a distribution of deviations in landing positions on a droplet landing observation substrate according to a first embodiment of the present disclosure; FIG. 1 is a diagram showing a list of in-plane SCAN direction misalignment amounts according to the first embodiment of the present disclosure; FIG. 13 is a table showing the deviation amounts for each of the first row of reference nozzles according to the first embodiment of the present disclosure; FIG. 1 is a diagram showing a list of two-dimensional deviations according to the first embodiment of the present disclosure. FIG. 1 is a diagram showing a list of one-dimensional deviations according to the first embodiment of the present disclosure. FIG. 13 is a diagram showing an ejection start position correction amount according to the first embodiment of the present disclosure. FIG. 1 is a diagram showing original image data according to the first embodiment of the present disclosure. FIG. 1 is a diagram showing two-dimensional displacement pixel amount data according to the first embodiment of the present disclosure; FIG. 1 is a diagram showing one-dimensional deviation pixel amount data according to the first embodiment of the present disclosure; FIG. 13 is a diagram showing the number of pixels for which an ejection end position is corrected according to the first embodiment of the present disclosure; FIG. 13 is a diagram showing the number of pixels when the ejection start position is corrected according to the first embodiment of the present disclosure; FIG. 1 is a diagram showing connections between main components that perform a correction operation according to a first embodiment of the present disclosure. FIG. 2 is a diagram showing an example of an internal configuration of a nozzle 2 variable delay unit in the nozzle-by-nozzle variable delay unit according to the first embodiment of the present disclosure; FIG. 13 is a diagram showing the state of a signal inside the nozzle 2 variable delay unit according to the first embodiment of the present disclosure over time. FIG. 13 is a diagram showing an example of the inclination state of the inkjet head according to the third and fourth embodiments of the present disclosure. FIG. 1 is a diagram for explaining the positional deviation of nozzle discharge holes due to yawing of a substrate, as disclosed in Patent Document 2. FIG. 1 is a diagram showing components that realize head ejection timing correction disclosed in Japanese Patent Application Laid-Open No. 2003-233696; FIG. 1 is a diagram showing the relationship between a print substrate and an inkjet head during a printing operation by moving a stage, as disclosed in Japanese Patent Application Laid-Open No. 2003-233696. FIG. 1 is a diagram showing assumed landing positions when droplets are discharged at uniform pitches onto a landing observation substrate, as disclosed in Patent Document 3. FIG. 1 shows print image data created based on assumed landing positions as disclosed in Japanese Patent Application Laid-Open No. 2003-233696.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Note that components common to each drawing are given the same reference numerals, and their description will be omitted as appropriate.

(Embodiment 1)
A printed circuit board 1 according to the present embodiment will be described below. Fig. 1 is a plan view (top view) of the printed circuit board 1. The printed circuit board 1 shown in Fig. 1 is, for example, a substrate for a display panel.

In FIG. 1, reference numeral 1a denotes a liquid-repellent film on the printed substrate 1. Reference numeral 1b denotes a bank on the liquid-repellent film 1a. The bank 1b extends in the nozzle row direction Y. Reference numeral 1c denotes a pixel region. The pixel region 1c is partitioned on the printed substrate 1 by the liquid-repellent film 1a and the bank 1b.

Bank 1b separates pixel regions 1c adjacent to each other in the left-right direction in the figure in the scan direction X. The spacing Lpx in the scan direction X is the spacing between the centers of pixel regions 1c adjacent to each other in the left-right direction in the figure (the intersection of the dashed dotted lines in the figure; the same applies below). The spacing Lpy in the nozzle row direction Y is the spacing between the centers of pixel regions 1c adjacent to each other in the up-down direction in the figure.

Lwx is the length of pixel area 1c in the SCAN direction X. Lwy is the length of pixel area 1c in the nozzle row direction Y. Pixel area 1c is a circular-edged rectangular area formed from its center by ±Lwx/2 in the SCAN direction X and ±Lwy/2 in the nozzle row direction Y.

Figures 2A to 2C are cross-sectional views of the printed circuit board 1.

Figure 2A shows the A-A cross section of Figure 1. The A-A cross section is a cross section of pixel region 1c cut out in the scan direction X. As shown in Figure 2A, there is no liquid-repellent film 1a in pixel region 1c between adjacent banks 1b.

Figure 2B shows the cross section B-B of Figure 1. The B-B cross section is a cross section cut out from a region in the scan direction X where there is no pixel region 1c. As shown in Figure 2B, a liquid-repellent film 1a is present in the pixel region 1c between adjacent banks 1b.

Figure 2C shows the CC cross section of Figure 1. The CC cross section is a cross section of pixel region 1c cut out in the nozzle row direction Y. As shown in Figure 2C, there is no bank 1b, and liquid-repellent film 1a is partially present in pixel region 1c.

Figure 3 shows the relationship between pixel area 1c and print ejection dot grid 2a.

Figure 3 shows one of the multiple pixel regions 1c shown in Figure 1.

The in-pixel landing area 1e has a length ewx in the SCAN direction X and a length ewy in the nozzle row direction Y, and is a pixel area in which ink droplets can land. The ink droplets to be landed within the pixel are ejected into this in-pixel landing area 1e.

The landing escape area 1d is the area obtained by subtracting the landing area 1d within the pixel from the pixel area 1c. The landing escape area 1d is a margin area that prevents the ink droplet from going beyond the pixel area 1c if it is ejected from the nozzle in a misaligned manner.

In FIG. 3, dotted lines (hereinafter referred to as first dotted lines) extending in the nozzle row direction Y are shown for each width corresponding to the printing resolution px in the SCAN direction X. Also, in FIG. 3, dotted lines (hereinafter referred to as second dotted lines) extending in the SCAN direction X are shown for each width corresponding to the printing resolution py in the nozzle row direction Y. The printing dot grid 2a is the intersection of the first dotted line and the second dotted line. The printing dot grid 2a can be the position where the ink droplets are expected to land (expected landing position 20 described later).

The method for determining the print resolution px in the SCAN direction X (hereinafter referred to as the SCAN direction print resolution px) and the print resolution py in the nozzle row direction Y (hereinafter referred to as the nozzle row direction print resolution py) will be described later.

The dot grid 2b within the landing area is the print ejection dot grid 2a arranged within the intra-pixel landing area 1e.

In this embodiment, an example is given of a case where eight ink droplets are ejected as standard within the in-pixel landing area 1e. In this case, the SCAN direction print resolution px and the nozzle row direction print resolution py are determined from the relationship between the eight ink droplets, the in-pixel landing area 1e, and the nozzle row direction spacing Lny (see FIG. 4) described below. In this embodiment, the SCAN direction print resolution px and the nozzle row direction print resolution py are determined so that a total of 12 dots (see FIG. 3), consisting of three dots in the SCAN direction X and four dots in the nozzle row direction Y, are secured within the in-pixel landing area 1e.

In FIG. 3, of the 12 dot grids 2b within the landing area, the dot grids 2b within the landing area for 8 droplets that will be ejected are indicated by black circles, and the dot grids 2b within the landing area for 4 droplets that will not be ejected are indicated by white circles. In addition, the dot grids 2b within the landing area for 8 droplets are positioned so that the center of gravity of the coordinate system of the dot grids 2b within the landing area for 8 droplets is located at the center of the pixel area 1c.

The inkjet printing device 100 of this embodiment will be described. Figure 4 is a block diagram showing the configuration of the inkjet printing device 100.

As shown in FIG. 4, the inkjet printing device 100 has an inkjet head 3, a moving stage 4, a position detector 5, an ejection timing generator 6, a drive signal generator 7, a normalized one-dimensional deviation information holder 8, a normalized two-dimensional deviation information holder 9, a print original image holder 10, a nozzle-by-nozzle deviation information adder 11, a nozzle-by-nozzle variable delay device 12, and a drive signal selector 13. The inkjet printing device 100 prints on a print substrate 1.

The inkjet head 3 has multiple nozzles 3a that eject ink droplets. In this embodiment, two inkjet heads 3 are provided along the nozzle row direction Y.

The nozzles 3a are arranged at intervals Lny along the nozzle row direction Y. This interval Lny is maintained even at the joint between the two inkjet heads 3. The nozzle row direction printing resolution py shown in Figure 3 is the same as the interval Lny.

The moving stage 4 moves the printed circuit board 1 that is placed on it.

The position detector 5 generates a position information pulse signal by converting the position information of the moving stage 4 on which the print substrate 1 is placed into a pulse signal, and outputs the pulse signal to the ejection timing generator 6.

The ejection timing generator 6 divides the position information pulse signal from the position detector 5 based on a preset SCAN direction printing resolution px, generates an ejection timing signal, and outputs the ejection timing signal to the drive signal generator 7, the normalized one-dimensional deviation information holder 8, the print original image holder 10, the nozzle-by-nozzle deviation information adder 11, and the nozzle-by-nozzle variable delay device 12. The ejection timing signal is a signal that specifies the generation timing of a voltage waveform that drives the nozzles 3a of the inkjet head 3.

The ejection timing generator 6 starts outputting the ejection timing signal according to the ejection start position information stored in the ejection timing generator 6. Then, the ejection timing generator 6 outputs the ejection timing signal the number of times indicated in the ejection count information stored in the ejection timing generator 6, and then stops generating and outputting the ejection timing signal.

The ejection timing generator 6 also generates a division timing signal and outputs it to the normalized two-dimensional misalignment information holder 9. The ejection timing generator 6 generates a signal that is generated by counting and thinning out the ejection timing according to the division width number information held in the ejection timing generator 6, and is a signal that specifies the timing for outputting the normalized two-dimensional misalignment amount to the nozzle-by-nozzle misalignment information adder 11.

The drive signal generator 7 generates a drive waveform signal for ejecting ink droplets from the nozzles 3a of the inkjet head 3 based on the ejection timing signal from the ejection timing generator 6, and outputs the signal to the drive signal selector 13.

The normalized one-dimensional displacement information holder 8 is a memory that holds normalized one-dimensional displacement pixel data, and outputs the normalized one-dimensional displacement pixel data to the nozzle-specific displacement information adder 11. The normalized one-dimensional displacement pixel data will be described later.

The normalized two-dimensional displacement information holder 9 is a memory that holds the normalized two-dimensional displacement pixel data. The normalized two-dimensional displacement information holder 9 outputs the normalized two-dimensional displacement pixel data to the nozzle-by-nozzle displacement information adder 11 in accordance with the division timing signal. The normalized two-dimensional displacement pixel data will be described later.

The print original image holder 10 is a memory that holds original image data (original print data) and outputs the original image data to the nozzle-specific variable delay device 12. The original image data is data for instructing the ejection of ink droplets onto the print ejection dot grid 2a set on the print substrate 1.

The nozzle-specific deviation information adder 11 adds the normalized one-dimensional deviation pixel data from the normalized one-dimensional deviation information holder 8 and the normalized two-dimensional deviation pixel data from the normalized two-dimensional deviation information holder 9 for each ejection timing signal. The nozzle-specific deviation information adder 11 then outputs deviation amount information indicating the deviation amount (delay amount) for each nozzle 3a obtained as a result of the addition to the nozzle-specific variable delay device 12.

The nozzle-by-nozzle variable delay unit 12 generates ejection on/off instruction information based on the original image data from the print original image holder 10 and the deviation amount information from the nozzle-by-nozzle deviation information adder 11, and outputs it to the drive signal selector 13. The ejection on/off instruction information is information that instructs each nozzle 3a to turn ejection on/off (execute/not execute) for each print ejection dot grid 2a.

The drive signal selector 13 turns on/off the drive waveform signal from the drive signal generator 7 for each nozzle 3a based on the ejection on/off instruction information from the nozzle-by-nozzle variable delay device 12. This controls the ejection of ink droplets from each nozzle 3a.

Before printing on the print substrate 1, the inkjet printing device 100 having the above-described configuration causes ink droplets to land on one surface of a droplet landing observation substrate (not shown) of the same size as the print substrate 1, and measures the amount of deviation between the actual landing position and the target landing position on the droplet landing observation substrate. Then, the inkjet printing device 100 determines one-dimensional landing deviation information and two-dimensional landing deviation information based on the measured amount of deviation.

Figure 5 shows the distribution of the deviation of the landing position on the droplet landing observation substrate. As shown in Figure 5, the printing range on the droplet landing observation substrate is divided into four equal parts in the SCAN direction X. The boundaries of the printing range in the SCAN direction X are, for example, x1, x9, x17, and x25. The interval for one division in the SCAN direction X (hereinafter, the division interval BKW) is, for example, 40.0 μm. The inkjet printing device 100 stores the positions of the boundaries and the division interval BKW. This BKW is stored in the ejection timing generator 6 as BKGSW divided by the SCAN direction printing resolution px. In addition, the inkjet head 3 is provided with, for example, 20 nozzles 3a for each nozzle row direction printing resolution py.

The inkjet printing device 100 ejects ink droplets from the nozzles 3a to a preset expected landing position 20. The expected landing position 20 is set along the nozzle row direction Y at the boundaries x1, x9, x17, and x25 of the printing range in the SCAN direction X.

The white circle in Fig. 5 represents the expected landing position 20. The black circle in Fig. 5 represents the position 21 where the ejected ink droplet actually lands (hereinafter referred to as the actual landing position 21). As shown in Fig. 5, there is a deviation between the expected landing position 20 and the actual landing position 21. In Fig. 5, the arrow between the expected landing position 20 and the actual landing position 21 represents the amount of deviation.

Figure 6A is a diagram showing a list of in-plane SCAN direction deviation amounts (unit: μm). The in-plane SCAN direction deviation amount is the deviation amount between the expected landing position 20 and the actual landing position 21 shown in Figure 5. The unit is μm.

In FIG. 6A, x1 represents the boundary x1 of the first column in FIG. 5 (hereinafter simply referred to as the first column), x2 represents the boundary x9 of the second column in FIG. 5 (hereinafter simply referred to as the second column), x3 represents the boundary x17 of the third column in FIG. 5 (hereinafter simply referred to as the third column), and x4 represents the boundary x25 of the fourth column in FIG. 5 (hereinafter simply referred to as the fourth column). The same is true for FIG. 6B and FIG. 6C.

The -14.2 μm at x1 and y15 shown in Figure 6A is the minimum deviation (1 DZRMIN) among the deviations at the boundary (x1) of the first row.

Figure 6B shows a list of the misalignment amounts for each reference nozzle in the first row. The misalignment amount for each reference nozzle in the first row is the difference between the in-plane SCAN direction misalignment amount in the first row and the in-plane SCAN direction misalignment amount in each of the second to fourth rows. The unit is μm.

For example, -6.8 μm at x2 and y2 shown in FIG. 6B is the value obtained by subtracting 4.1 μm at x1 and y2 shown in FIG. 6A from -2.7 μm at x2 and y2 shown in FIG. 6A.

In addition, -8.0 μm at x4 and y17 shown in Figure 6B is the smallest difference amount (2DZRMIN) among all the values shown in Figure 6B.

Figure 6C shows a list of two-dimensional deviations (hereafter referred to as the two-dimensional deviation table). The two-dimensional deviation is calculated by subtracting the two-dimensional minimum deviation difference (2DZRMIN) from each of the difference amounts (deviation amount for each reference nozzle in the first row) shown in Figure 6B, and normalizing the result to a positive value. The unit is μm.

For example, 1.2 μm at x2 and y2 in FIG. 6C is the value obtained by subtracting -8.0 μm, which is the two-dimensional deviation minimum difference amount (2DZRMIN) shown in FIG. 6B, from -6.8 μm at x2 and y2 in FIG. 6B.

Figure 6D is a diagram showing a list of one-dimensional deviations (hereinafter referred to as the one-dimensional deviation table). The one-dimensional deviation is a value obtained by subtracting the one-dimensional deviation minimum difference amount (1DZRMIN) from each of the in-plane SCAN direction deviation amounts in the first column shown in Figure 6A, and normalizing the result to a positive value. The unit is μm.

For example, 18.3 at y2 in Figure 6D is the value obtained by subtracting -14.2 μm, which is the one-dimensional minimum deviation amount (1DZRMIN) shown in Figure 6A, from 4.1 μm at x1 and y2 shown in Figure 6A.

Figure 6E shows the ejection start position correction amount. The ejection start position correction amount is the sum of the one-dimensional minimum deviation amount (1DZRMIN) and the two-dimensional minimum deviation amount (2DZRMIN). The unit is μm.

For example, -22.2 shown in Figure 6E is the sum of -14.2 μm, which is the one-dimensional minimum deviation amount (1DZRMIN) shown in Figure 6A, and -8.0 μm, which is the two-dimensional minimum difference amount (2DZRMIN) shown in Figure 6B.

The reason why the values in the one-dimensional deviation table and the two-dimensional deviation table are set to positive values is to set the deviation amount (details will be described later) that can be used by the nozzle-specific variable delay device 12.

<Process>
The process of the printing operation performed by the inkjet printing apparatus 100 will be described below.

(1) Data Storage Process First, various data are stored.

Specifically, the print original image holder 10 stores original image data. The normalized one-dimensional displacement information holder 8 stores normalized one-dimensional displacement pixel data. The normalized two-dimensional displacement information holder 9 stores normalized two-dimensional displacement pixel data.

Figure 7 shows an example of original image data.

As shown in FIG. 7, the original image data (20 nozzles and 31 scans) is divided into a grid by the scan direction print resolution px and the nozzle row direction print resolution py. The grid here is the print dot grid 2a shown in FIG. 3.

Also, as shown in FIG. 7, multiple pixel regions 1c are set in the original image data. Each pixel region 1c is the same as that shown in FIG. 3. The black circles shown in the landing regions 1e within each pixel indicate the dot grid 2b within the landing regions for the eight droplets that will be ejected, as in FIG. 3.

Figure 8A is a diagram showing an example of two-dimensional misalignment pixel amount data. The two-dimensional misalignment pixel amount data shown in Figure 8A corresponds to an example of a two-dimensional misalignment correction amount.

The two-dimensional displacement pixel amount data is converted to pixel amount by dividing each value in the two-dimensional displacement table shown in Figure 6C by the SCAN direction resolution px (e.g., 5.0 μm).

For example, 0.24 pixels at x2 and y2 in Figure 8A is the value obtained by dividing 1.2 μm at x2 and y2 in Figure 6C by 5.0 μm.

Also, the 3.44 pixels at x4 and y1 shown in Figure 8A is the maximum value (2DZRGSMAX) of all the values shown in Figure 8A.

Figure 8B is a diagram showing an example of one-dimensional misalignment pixel amount data. The one-dimensional misalignment pixel amount data shown in Figure 8B corresponds to an example of a one-dimensional misalignment correction amount.

The one-dimensional displacement pixel amount data is converted to pixel amount by dividing each value in the one-dimensional displacement table shown in Figure 6D by the SCAN direction resolution px (e.g., 5.0 μm).

For example, the 3.66 pixels at y2 shown in Figure 8B is the value obtained by dividing 18.3 μm at y2 shown in Figure 6D by 5.0 μm.

Also, the 4.8 pixels at y12 shown in Figure 8B is the maximum value (1DZRGSMAX) among all the values shown in Figure 8B.

Figure 8C shows an example of the pixel quantity for ejection end position correction. The 8.24 pixels shown in Figure 8 are the sum of 3.44 pixels, which is 2DZRGSMAX shown in Figure 8A, and 4.8 pixels, which is 1DZRGSMAX shown in Figure 8B.

The sum of the ejection end position correction pixel quantity and the SCAN number of the original image data is stored in the ejection timing generator 6 as ejection count information. For example, the sum of 3.44 pixels, which is 2DZRGSMAX, and 4.8 pixels, which is 1DZRGSMAX, is 8.24 pixels, and since the SCAN number of the original image data is 31, the total sum is 39.24. This value is rounded up to an integer value and stored in the ejection timing generator 6 as ejection count information "40 pixels".

The interval (μm) for one division in the SCAN direction is converted into a division interval pixel to obtain the division interval pixel BKGSW, which is the feed interval of the normalized two-dimensional offset pixel amount data, and this is stored as division interval information in the ejection timing generator 6. For example, since BKW=40.0 μm and px=5.0 μm, BKGSW=8.

Furthermore, the sum (μm) of the one-dimensional deviation minimum difference amount (1DZRMIN) and the two-dimensional deviation minimum difference amount (2DZRMIN) is converted to a minimum difference amount pixel to obtain the ejection start position correction amount (pixels) for generating an ejection timing signal. The ejection timing signal starts to be generated when the top of the original image reaches the nozzle position, and this generation start position is corrected by the ejection timing signal generation start position correction amount. Since the one-dimensional deviation minimum difference amount (1DZRMIN) is -14.2 μm, the two-dimensional deviation minimum difference amount (2DZRMIN) is -8.0 μm, and px = 5.0 μm, the generation start position correction amount (pixels) = -4.44 pixels (see Figure 8D).

The following is a summary of the terms used in this embodiment regarding misalignment.

The landing deviation (μm) is the amount of deviation between an expected landing position 20 and an actual landing position 21 (see, for example, FIG. 6A).
The one-dimensional landing deviation (μm) is the amount of landing deviation in the first row (see, for example, the row x=1 in FIG. 6A).
The two-dimensional landing deviation (μm) is the difference between the one-dimensional landing deviation and the landing deviation for each row (for example, each row of x=2 to 4 in FIG. 6A) (for example, see FIG. 6B).
The normalized two-dimensional deviation (μm) is the amount of deviation obtained by normalizing the two-dimensional impact deviation to a positive value (see, for example, FIG. 6C).
The normalized one-dimensional deviation (μm) is the deviation amount obtained by normalizing the one-dimensional landing deviation to a positive value (see, for example, FIG. 6D).
The normalized two-dimensional displacement (pixels) is data obtained by normalizing the normalized two-dimensional displacement by the SCAN direction printing resolution px (see, for example, FIG. 8A).
The normalized one-dimensional displacement (pixels) is data obtained by normalizing the normalized one-dimensional displacement by the SCAN direction printing resolution px (for example, see FIG. 8B).
The information on the number of ejections (times) is the number of ejections required to eject all of the original image that has been corrected for misalignment.
The division interval pixel (pixel) is the interval for extracting normalized two-dimensional displacement pixel data.
The ejection end position correction amount (pixels) is a correction amount (positive value) by which the ejection end position is shifted in order to eject the total offset correction amount of the original image by adding up the absolute amount of the negative offset of the offset-corrected original image and the positive offset amount (see Figure 8C).
The ejection start position correction amount (pixels) is a correction amount (negative value) by which the ejection start position is shifted in order to correct the negative shift of the shift-corrected original image (see FIG. 8D).

(2) Discharge Step Next, printing is performed by discharging ink droplets. In the following, first, the overall flow of the printing operation will be described, and then the correction operation will be described in detail.

The print timing generator 6 is set to generate an ejection timing signal at an ejection start position corrected by an ejection start position correction amount (pixels) = -4.44 pixels, and at a scan direction print resolution px, ejection count information (times) = 40 times. The print timing generator 6 is also set to generate a division timing signal every time an ejection timing signal is generated for division interval pixels (pixels) = 8 pixels.

When the moving stage 4 on which the print substrate 1 is placed moves relative to the inkjet head 3, position information is generated in a time series.

The position information is input to the position detector 5. The position detector 5 generates a position information pulse signal by converting the position information into a pulse signal, and outputs the pulse signal to the ejection timing generator 6.

The ejection timing generator 6 divides the position information pulse signal from the position detection unit 5 based on a preset SCAN direction printing resolution px, generates an ejection timing signal, and outputs it to the drive signal generator 7. As described above, the ejection timing signal is a signal that specifies the generation timing of the voltage waveform that drives the nozzles 3a of the inkjet head 3. The ejection timing signal is also output to the print original image holder 10, the nozzle-by-nozzle shift information adder 11, and the nozzle-by-nozzle variable delay unit 12. The divided timing signal is output to the normalized two-dimensional shift information holder 9.

The drive signal generator 7 generates a drive waveform signal based on the ejection timing signal from the ejection timing generator 6, and outputs the drive waveform signal to the drive signal selector 13. As described above, the drive waveform signal is a signal for ejecting ink droplets from the nozzles 3a of the inkjet head 3.

Meanwhile, the print original image holder 10 outputs the original image data, which is logical print bitmap data, to the nozzle-specific variable delay device 12 in synchronization with the ejection timing signal. As described above, the original image data is data for instructing the ejection of ink droplets onto the print ejection dot grid 2a set on the print board 1.

The normalized one-dimensional deviation information holder 8 also synchronizes the normalized one-dimensional deviation data (pixel) amount for each nozzle 3a with the ejection timing signal and outputs it to the per-nozzle deviation information adder 11. The normalized two-dimensional deviation information holder 9 synchronizes the normalized two-dimensional deviation data (pixel) amount for each nozzle 3a with the division timing signal and outputs it to the per-nozzle deviation information adder 11.

The nozzle-specific deviation information adder 11 adds the normalized one-dimensional deviation data (pixels) for each nozzle 3a from the normalized one-dimensional deviation information holder 8 and the normalized two-dimensional deviation data (pixels) amount for each nozzle 3a from the normalized two-dimensional deviation information holder 9 for each ejection timing signal. The nozzle-specific deviation information adder 11 then outputs deviation amount information indicating the deviation amount (delay amount) for each nozzle obtained as a result of the addition to the nozzle-specific variable delay device 12.

The nozzle-by-nozzle variable delay device 12 generates ejection on/off instruction information based on the original image data from the print original image holder 10 and the deviation amount information from the nozzle-by-nozzle deviation information adder 11, and outputs it to the drive signal selector 13. As described above, the ejection on/off instruction information is information that instructs each nozzle 3a to turn ejection on/off (execute/not execute) for each print ejection dot grid 2a.

The drive signal selector 13 turns on/off the drive waveform signal from the drive signal generator 7 for each nozzle 3a based on the ejection on/off instruction information from the nozzle-by-nozzle variable delay device 12. This controls the ejection of ink droplets from each nozzle 3a.

While the moving stage 4 passes under the inkjet head 3 at a predetermined speed, the above-mentioned operations are repeated, and ink droplets are ejected onto the print board 1 based on the original image data. Then, when the moving stage 4 has finished passing under the inkjet head 3, the ejection of ink droplets based on the original image data is completed.

Next, we will explain the correction operation, which is a feature of this embodiment. In this correction operation, the original image data and landing deviation information are set in advance in each holder, thereby correcting the landing deviation for each nozzle 3a and the in-plane landing deviation on the printed board 1 that occurs due to the yawing of the moving stage 4.

Figure 9 is a diagram showing the connections between the main components of the inkjet printing device 100 shown in Figure 4 that perform correction operations.

As shown in FIG. 9, the normalized one-dimensional shift information holder 8, the normalized two-dimensional shift information holder 9, the print original image holder 10, the nozzle-by-nozzle shift information adder 11, and the nozzle-by-nozzle variable delay device 12 are connected to each nozzle 3a. In FIG. 9, #1 to #20 indicate the identification numbers of the 20 nozzles 3a.

Also, as shown in FIG. 9, the nozzle variable delay unit 12 has 20 variable delay units (nozzle 1 variable delay unit to nozzle 20 variable delay unit 12).

Figure 10 shows an example of the internal configuration of the nozzle 2 variable delay unit in the nozzle-by-nozzle variable delay unit 12 shown in Figures 4 and 9.

Reference symbols 30a-h are pixel holders (1-bit flip-flops) that hold the D input value in Q at the rising edge of the CK clock signal. Q is cleared to 0 by the /CLR signal.

Reference symbols 31a to 31h are logical multipliers (AND gates) that output the logical product (AND) of two inputs.

Reference symbols 32a to 32h are some negative logic multipliers (one-input negative logic AND gates) that output the logical product (AND) of one positive logic input and one negative logic input.

Reference symbols 33a to 33h are logical adders (OR gates) that output the logical sum (OR) of two inputs.

Reference numeral 34 denotes a decoder, which outputs positive logic bits to S1 to S8 according to the numerical values 1 to 8. When the input value is 1, S1 is 1 and S2 to S8 are each 0. When the input value is 2, S1 to S2 are each 1 and S3 to S8 are each 0. When the input value is 3, S1 to S3 are each 1 and S4 to S8 are each 0. When the input value is 4, S1 to S4 are each 1 and S5 to S8 are each 0. When the input value is 5, S1 to S5 are each 1 and S6 to S8 are each 0. When the input value is 6, S1 to S6 are each 1 and S7 to S8 are each 0. When the input value is 7, S1 to S7 are each 1 and S8 is 0. When the input value is 8, S1 to S8 are all 1.

Figure 11 shows the state of the signal inside the nozzle 2 variable delay unit shown in Figure 10 over time.

The correction operation during printing will be explained below using nozzle #2 (hereafter referred to as the second nozzle) as an example.

As shown in Figure 9, the normalized one-dimensional displacement information holder 8 holds 3.66 (unit: pixel) as the one-dimensional displacement pixel amount data for the second nozzle. Also, as shown in Figure 9, the normalized two-dimensional displacement information holder 9 holds 1.6, 0.24, 1.04, and 2.44 (unit: pixel) as the two-dimensional displacement pixel amount data for the second nozzle.

The print original image holder 10 holds a sequence of numbers indicating whether the print ejection dot grid 2a is an ejection target (black circle) or a non-ejection target (white circle) in the order of x1 to x31 of y2 in Figure 7 as the original image data for the second nozzle. For example, the original image data for the second nozzle is 0 (non-ejection target), 0, 0, 1 (ejection target), 1, 0, 0, 0, 0, ... 1, 1, 0, 0.

The one-dimensional offset pixel amount data for the second nozzle, 3.66, is output to the nozzle-specific offset information adder 11 in synchronization with the ejection timing signal.

The one-dimensional pixel shift data for the second nozzle, 1.6, 0.24, 1.04, and 2.44, are output in sequence to the nozzle-specific shift information adder 11 in synchronization with the division timing signal.

In the nozzle-by-nozzle shift information adder 11, the one-dimensional shift pixel amount data of the second nozzle and the one-dimensional shift pixel amount data of the second nozzle are arithmetically added. Then, the added value (in other words, the delay amount) is output as the selection data SEL#2 signal to the nozzle 2 variable delay of the nozzle-by-nozzle variable delay 12, as shown in FIG. 10.

Meanwhile, the original image data for the second nozzle is output to the nozzle 2 variable delay of the nozzle-by-nozzle variable delay unit 12 in synchronization with the ejection timing signal in the order described above. As shown in FIG. 10, the original image data for the second nozzle is output to the nozzle 2 variable delay unit as the selection data Din#2 signal.

Figure 11 shows the values of SEL#2 and Din#2 for each ejection timing t = 1 to 40.

Here, using Figures 10 and 11, we will explain the operation in which Din#2 is delayed based on SEL#2 and output as Dout#2.

First, as shown in FIG. 10, the *CLR signal is output from the ejection timing generator 6 to the nozzle 2 variable delay device, and the Q output of the pixel holders 30a-h is cleared to 0.

As shown in FIG. 11, at time t=1, the nozzle-specific shift information adder 11 calculates 3.66 (1Dzure#2: one-dimensional shift pixel amount data) + 1.6 (2Dzure#2: two-dimensional shift pixel data for the first row) = 5.26 pixels (SEL#2.float). Then, the 5 pixels obtained by truncating the decimal points of the 5.26 pixels are output from the nozzle-specific shift information adder 11 to the decoder 34 of the nozzle 2 variable delay device as the SEL#2 signal.

In the decoder 34 shown in FIG. 10, S1 to S5 each output 1, and S6 to S8 each output 0.

The logic multipliers 31a to 31e, the partial negative logic multipliers 32a to 32e, and the logic adders 33a to 33e connected to S1 to S5 transmit the Q output of the pixel holders 30a to 30e to Dout#2 or the D input of the pixel holders 30a to 30d.

The logical multipliers 31f-31h, partial negative logic multipliers 32f-32h, and logical adders 33f-33h to which S6-S8 are connected transmit the input of Din#2 to the D inputs of pixel holders 30e-30g. Din#2 is input to the D input of pixel holder 30h. When the CLK signal from the ejection timing generator 6 rises, the D input value to pixel holders 30a-30h is held and output to Q.

As shown in FIG. 11, at times t=1 to 3, Din#2=0, so Q of pixel holders 30a to 30h remains at 0. At times t=4 and t=5, when Din#2=1, Din#2 is transmitted to D5 of pixel holder 30e. Then, at times t=6 to 8, Din#2 is transmitted in sequence from D5 of pixel holder 30e to image holders 30a to 30d, resulting in a delay of five pixels.

After that, as shown in FIG. 11, when SEL#2 changes from 5 to 3 at t=9, the output destination of Din#2 is switched to D4 to D3. As a result, at t=7 to 8, the values held in Q of pixel holders 30d to 30e are discarded, and from t=9, the amount of delay changes from 5 pixels to 3 pixels.

Similarly, at t=17, when the SEL#2 signal changes from 3 to 4, the delay amount changes from 3 pixels to 4 pixels. At t=25, when the SEL#2 signal changes from 4 to 6, the delay amount changes from 4 pixels to 6 pixels. Then, at time t=40, the delay operation is completed.

As shown in FIG. 11, a value of 1 is output as Dout#2 at times t=9, 10, t=15, 16, t=24, 25, t=34, and 35.

As described above, the value indicated in Din#2 is delayed based on the increase or decrease in the delay amount indicated in SEL#2, and is output as Dout#2.

If the Din pixel is an ejection pixel at time t when the two-dimensional misalignment is decreasing, the SEL signal may not be switched until time t+n when the Din pixel becomes a non-ejection pixel. This makes it possible to prevent the ejection pixel from being deleted.

Also, if the division pixel interval is a decimal pixel value, the accumulation can be performed using a decimal adder, and the two-dimensional deviation pixel amount data can be switched when the integer interval value is crossed. This makes it possible to suppress the cumulative error that occurs when the decimal division position is converted to an integer, and to limit it to only the fractional error.

In the inkjet printing device 100 of this embodiment, the original image data is stored in the print original image holder 10, and when the ejection position changes due to a change in the characteristics of the nozzle 3a of the inkjet head 3, the one-dimensional displacement pixel amount data representing that characteristic is stored in the normalized one-dimensional displacement information holder 8, and when the movement characteristics of the moving stage 4 change, the two-dimensional displacement pixel amount data representing that characteristic is stored in the normalized two-dimensional displacement information holder 9, and the original image data is printed based on these data. That is, the inkjet printing device 100 is characterized in that the original image data and the two-dimensional displacement pixel amount data are stored separately, and the original image data is printed based on the sum of the one-dimensional displacement pixel amount data and the two-dimensional displacement pixel amount data. Therefore, when correcting the one-dimensional displacement, only the one-dimensional displacement pixel amount data needs to be rewritten, and when correcting the two-dimensional displacement, only the two-dimensional displacement pixel amount data needs to be rewritten, so that there is no need to reflect both displacement pixel amounts in the original image data or write the original image data to memory. There is also no need to replace the original image data in the print original image holder 10. Therefore, the processing time required for printing preparation can be significantly reduced. In other words, the inkjet printing device 100 of this embodiment can correct the deviation of the landing position of ink droplets while reducing the processing time. As a result, it can greatly contribute to the provision of high-quality displays with little mixed-color emission and brightness unevenness, and electronic devices having such displays, which meet the needs of larger display panels, multi-panel printing, and shorter printing takt times due to increased production volume.

(Embodiment 2)
The inkjet printing apparatus 100 does not necessarily have to include the normalized one-dimensional misalignment information holder 8 and the nozzle-by-nozzle misalignment information adder 11 among the components shown in FIG.

In this case, the one-dimensional deviation pixel amount data and the two-dimensional deviation pixel amount data for each nozzle 3a may be added together by software processing, and the resulting added value may be stored in the normalized two-dimensional deviation information holder 9 instead of the two-dimensional deviation pixel amount data. This allows the same operation as in embodiment 1 to be realized.

In this case, the sum may be stored in the normalized two-dimensional deviation information holder 9 as integer data with the decimal point discarded. This allows for a reduction in memory and circuit size compared to embodiment 1, in which the sum is decimal data.

(Embodiment 3)
In order to reduce the nozzle pitch Lny shown in FIG. 4, if the arrangement of the two inkjet heads 3 shown in FIG. 4 is tilted obliquely with respect to the SCAN direction X as shown in FIG. 12, a nozzle pitch LnX in the SCAN direction X (hereinafter referred to as the SCAN direction nozzle pitch LnX) will be generated.

In the first embodiment, a specified control computer (software) is used to shift the original image data by n times the SCAN direction nozzle pitch LnX for each nozzle 3a (hereinafter referred to as shift processing), thereby enabling misalignment-corrected printing. The amount of shift for each nozzle 3a is recalculated each time the SCAN direction print image resolution px changes, and the original image data is shifted based on this. Note that the above n is determined based on Lnx and the division value each time the SCAN direction print resolution px of the original image data is changed. In this case, a fraction (decimal number) is generated, but this fraction is added to the one-dimensional shift pixel amount data of the normalized one-dimensional shift information holder 8.

Shift processing is a process in which the original image data itself is processed to match the arrangement of the nozzles 3a. While the arrangement of the nozzles 3a is determined at the time of design, impact misalignment occurs due to the installation of the inkjet head 3 and the ejection state of the inkjet head 3 itself (machine difference). In shift processing, the latter is corrected based on one-dimensional shift pixel amount data, and the former is processed by processing the original image data itself to match the arrangement of the nozzles 3a. Compared to the frequency of processing the misalignment correction amount, the frequency of creating original image data is not high, so even if the original image data is large, the time required for processing does not put a strain on production.

(Embodiment 4)
This embodiment is a method for correcting the deviation of n times LnX, as described in the third embodiment, without processing the original image data.

In addition to the components shown in FIG. 4, the inkjet printing device 100 includes a nozzle arrangement shift information holder (not shown) that holds the amount of shift for each nozzle 3a. This amount of shift for each nozzle 3a is recalculated each time the SCAN direction print image resolution px changes, and is stored in the nozzle arrangement shift information holder.

The nozzle shift information adder 11 expands the variable delay range of the nozzle variable delayer 12 to a range that can correct shifts of n times LnX based on the shift amount for each nozzle 3a stored in the nozzle arrangement shift information holder.

In this embodiment, misalignment-corrected printing is possible without processing the original image data.

This disclosure is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the disclosure.

The inkjet printing device and inkjet printing method disclosed herein are useful for correcting deviations in the landing positions of ink droplets.

REFERENCE SIGNS LIST 1 Printing substrate 1a Liquid-repellent film 1b Bank 1c Pixel area 1d Landing escape area 1e Landing area within pixel 2a Printing ejection dot grid 2b Dot grid within landing area 3 Inkjet head 3a Nozzle hole 4 Moving stage 5 Position detector 6 Print timing generator 7 Drive signal generator 8 Normalized one-dimensional deviation information holder 9 Normalized two-dimensional deviation information holder 10 Print original image holder 11 Per-nozzle deviation information adder 12 Per-nozzle variable delay device 13 Drive signal selector 20 Expected landing position 21 Landing position 30a-h Pixel holder (1-bit flip-flop)
31a-h Logic multiplier (AND gate)
32a-h Partially negative logic multiplier (one-input negative logic AND gate)
33a-h Logical adder (OR gate)
34 Decoder 100 Inkjet printing device

Claims (7)

An inkjet printing apparatus having a moving stage for moving a print substrate and an inkjet head for ejecting ink droplets from a plurality of nozzles onto the print substrate,
a print master holder for holding master data indicative of landing positions of the ink droplets on the print substrate;
a deviation information holder that holds a two-dimensional deviation correction amount used to correct a two-dimensional deviation of the landing position of the ink droplet for each nozzle and a one-dimensional deviation correction amount used to correct a one-dimensional deviation;
a nozzle-by-nozzle variable delay unit that generates ejection on/off instruction information that changes the ejection timing of the ink droplets based on the original image data and the one-dimensional deviation correction amount and the two-dimensional deviation correction amount ;
a drive signal selector that turns on/off the ejection of the ink droplets for each of the nozzles based on the ejection on/off instruction information,
Calculating the one-dimensional misalignment correction amount and the two-dimensional misalignment correction amount based on an in-plane scanning direction misalignment amount of each nozzle.
Inkjet printing device. The two-dimensional deviation correction amount is
Calculate the amount of in-plane scanning direction deviation for each row of each nozzle in the scanning direction,
Calculating a reference nozzle-by-nozzle shift amount, which is an in-plane scanning direction shift amount in another scan row based on the in-plane scanning direction shift amount in a predetermined scan row;
Calculating a two-dimensional deviation by subtracting the minimum reference per-nozzle deviation amount from the reference per-nozzle deviation amount;
Calculating the two-dimensional deviation by dividing the two-dimensional deviation by a scanning direction resolution;
The one-dimensional deviation correction amount is
Calculating a one-dimensional shift by adding the minimum in-plane scanning direction shift amount in the predetermined scan row to the in-plane scanning direction shift amount of the predetermined scan row;
Calculate the one-dimensional deviation by dividing the one-dimensional deviation by a scanning direction resolution;
The inkjet printing apparatus of claim 1 . The two-dimensional deviation correction amount is
Calculate the amount of in-plane scanning direction deviation for each row of each nozzle in the scanning direction,
Calculating a first row reference nozzle-by-nozzle deviation amount, which is an in-plane scanning direction deviation amount in another scan row based on the in-plane scanning direction deviation amount in the first scan row;
Calculating a two-dimensional deviation by subtracting the minimum deviation amount for each of the first row reference nozzles from the deviation amount for each of the first row reference nozzles;
Calculating the two-dimensional deviation by dividing the two-dimensional deviation by a scanning direction resolution;
The one-dimensional deviation correction amount is
calculating a one-dimensional shift by adding the minimum in-plane scanning direction shift amount in the first scan row to the in-plane scanning direction shift amount of the first scan row;
Calculate the one-dimensional deviation by dividing the one-dimensional deviation by a scanning direction resolution;
The inkjet printing apparatus of claim 1 . a one-dimensional deviation information holder that holds the one-dimensional deviation correction amount;
a two-dimensional misalignment information holder that holds the two-dimensional misalignment correction amount;
a nozzle-by-nozzle misalignment information adder that calculates a sum by adding the one-dimensional misalignment correction amount held in the one-dimensional misalignment information holder and the two-dimensional misalignment correction amount held in the two-dimensional misalignment information holder,
The inkjet printing apparatus according to any one of claims 1 to 3 . The additional value is an integer.
5. The inkjet printing apparatus of claim 4 . when a nozzle pitch occurs in the SCAN direction due to the inkjet head being disposed at an angle with respect to the SCAN direction, the nozzle pitch is corrected based on the shift amount for each nozzle.
The inkjet printing apparatus according to any one of claims 1 to 5 . An inkjet printing method using a moving stage that moves a print substrate and an inkjet head that ejects ink droplets from a plurality of nozzles onto the print substrate, comprising:
original image data indicating landing positions of the ink droplets on the printing substrate;
a two-dimensional deviation correction amount used for correcting a two-dimensional deviation of the landing position of the ink droplet for each nozzle and a one-dimensional deviation correction amount used for correcting a one-dimensional deviation are stored in separate memories;
generating ejection on/off instruction information that changes the ejection timing of the ink droplets based on the original image data and the one-dimensional deviation correction amount and the two-dimensional deviation correction amount ;
Turning on/off the ejection of the ink droplets for each of the nozzles based on the ejection on/off instruction information;
Calculating the one-dimensional misalignment correction amount and the two-dimensional misalignment correction amount based on an in-plane scanning direction misalignment amount of each nozzle.
Inkjet printing method.