JP4608849B2 - Liquid ejection apparatus, correction pattern forming method, and liquid ejection system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid ejection apparatus, a correction pattern forming method, and a liquid ejection system.
[0002]
[Prior art]
Inkjet printers, which are typical liquid ejection devices, are already well known. This ink jet printer includes an ink jet type ejection head that ejects ink as an example of liquid from nozzles, and is configured to record images, characters, and the like by ejecting ink onto printing paper as an example of a medium. ing. In some inkjet printers, the ejection head includes a plurality of nozzle arrays, and color printing is performed by ejecting ink from each nozzle array. Some have a function of performing so-called “bidirectional printing” in which printing is performed by ejecting ink in the forward path and the backward path in order to improve the printing speed.
[0003]
By the way, in order to record an image, a character, etc. with such an ink jet printer, when forming dots on printing paper by ejecting ink, there is a case where deviation occurs in the dot formation position in the main scanning direction. The misalignment is, for example, a dot formation position in the main scanning direction of dots formed by ejecting liquid from the first nozzle row among the plurality of nozzle rows and another second nozzle different from the first nozzle row. A dot formation position in the main scanning direction of dots formed by ejecting liquid from the row, and a dot formation position in the main scanning direction of dots formed in the forward path of the bidirectional printing, and a return path This is a deviation from the dot formation position in the main scanning direction of the dots formed in FIG. Such misalignment of the dot formation position causes quality degradation of recorded images, characters, and the like, and therefore it is necessary to correct the misalignment.
[0004]
As a measure for correcting the deviation of the dot formation position, a correction pattern for correcting the deviation having a plurality of sub-patterns having different densities is formed on the printing paper by ejecting ink from the ejection head, A method has been proposed in which the density of each sub-pattern is read by a reading means, and the deviation is corrected based on the read density information (see, for example, Patent Document 1).
Further, in order to thoroughly correct the deviation, for example, it is necessary to form a plurality of correction patterns for each nozzle row.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-329381
[Problems to be solved by the invention]
However, regarding the above-described procedure for forming a plurality of correction patterns, if each of the correction patterns is formed one by one while inserting paper feed, the procedure becomes inefficient.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid ejection apparatus and a correction pattern for efficiently performing a correction pattern forming process for correcting a shift in dot formation position. It is to realize a forming method and a liquid discharge system.
[0007]
[Means for Solving the Problems]
The main invention includes a sub-scanning movement mechanism that moves the medium in the sub-scanning direction, and a nozzle row in which nozzles for forming dots on the medium by ejecting liquid are arranged in a row along the sub-scanning direction. An ejection head having a main scanning movement mechanism that moves the ejection head in a main scanning direction that intersects the sub-scanning direction; Drive control means for forming a plurality of correction patterns for correcting dot formation positions on the medium, wherein the discharge head includes a first nozzle row for discharging a first color liquid, a second nozzle a second nozzle array for discharging the color of the liquid, and a third nozzle array for ejecting a third color of the liquid, are arranged in the main scanning direction, the drive control unit, the discharge head is moved When the first The difference between the timing of ejection from the nozzle row and the timing of ejection from the third nozzle row is shifted by the distance obtained by dividing the ideal inter-dot distance into N equal parts (N is a natural number), and the respective distances are shifted. A plurality of sub-patterns are formed side by side in the main scanning direction to control to form a first correction pattern composed of the plurality of sub-patterns, and when the ejection head moves, The difference between the timing of ejection from the second nozzle row and the timing of ejection from the third nozzle row is shifted by the distance obtained by dividing the ideal inter-dot distance into N equal parts (N is a natural number), and the respective distances. A plurality of sub patterns shifted from each other are formed side by side in the main scanning direction, and a second correction pattern constituted by the plurality of sub patterns is converted into the first correction pattern. The sub-scanning movement mechanism executes the control of forming the pattern side by side in the sub-scanning direction, and the second scanning pattern is formed side by side in the sub-scanning direction with respect to the first correction pattern. In the liquid ejection device, the medium is not moved in the sub-scanning direction when the medium is moved.
Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
At least the following will be made clear by the description of the present specification and the accompanying drawings.
A nozzle pattern in which nozzles for forming dots on a medium by ejecting liquid are arranged in a line, and a correction pattern having a plurality of sub-patterns having different densities, wherein the density of the sub-pattern A liquid ejecting apparatus for ejecting the liquid from the nozzle row to form a plurality of correction patterns for correcting deviations in dot formation positions in the intersecting direction intersecting the direction of the nozzle row based on the difference between the nozzle rows The liquid ejecting apparatus according to claim 1, wherein the operation of forming the correction pattern is executed in parallel for the plurality of correction patterns.
By performing the operation for forming the correction pattern in parallel for a plurality of the correction patterns, it is possible to efficiently perform the correction pattern forming process for correcting the shift of the dot formation position. It becomes.
[0009]
Further, it is also possible to have density reading means for reading the density of the sub pattern, read the density of the sub pattern by the density reading means, and correct the deviation based on the read density information.
In this way, it is possible to easily obtain density information for correcting the deviation.
[0010]
The correction pattern includes a plurality of nozzle rows, and the correction pattern includes dot formation positions in the intersecting direction of dots formed by ejecting liquid from the first nozzle row of the plurality of nozzle rows, and the first pattern. It is a correction pattern for correcting a deviation between the dot formation position in the intersecting direction of dots formed by discharging liquid from another second nozzle row different from the nozzle row, and from the first nozzle row A second nozzle having a dot formed by ejecting liquid and a dot formed by ejecting liquid from the second nozzle row, and the second nozzle; The plurality of sub-patterns formed by changing the difference from the timing of discharging the liquid from the column for each sub-pattern may be provided.
In such a case, the Uni-D adjustment pattern forming process can be efficiently performed.
[0011]
Further, the color of the liquid ejected from the first nozzle row of the plurality of correction patterns that includes three or more nozzle rows that eject liquids of different colors and that the operation is performed in parallel. The plurality of correction patterns may be the same, and the color of the liquid ejected from the second nozzle row may be different for each of the plurality of correction patterns.
In such a case, since it becomes more important to form a plurality of correction patterns and perform shift correction for each correction pattern, the above-described effect, that is, the Uni-D adjustment pattern formation process is performed. The effect that it becomes possible to perform efficiently will be exhibited more notably.
[0012]
Further, one of the three or more nozzle rows is defined as the first nozzle row, and each of the remaining nozzle rows is formed as the second nozzle row, and the number of nozzle rows is corrected by subtracting one. A correction pattern group including a correction pattern is formed, and the above operation may be executed in parallel for at least two correction patterns forming the correction pattern group.
In this way, the Uni-D adjustment can be performed thoroughly.
[0013]
The correction pattern is formed by ejecting liquid from the nozzle row in the crossing direction of dots formed by ejecting liquid from the nozzle row in the main scanning forward pass and from the nozzle row in the backward pass. It is a correction pattern for correcting deviation of dots from the dot formation position in the intersecting direction, and is formed by ejecting liquid from the nozzle row in the main scanning forward path, and liquid from the nozzle row in the backward path And the difference between the timing at which liquid is ejected from the nozzle row in the forward path of main scanning and the timing at which liquid is ejected from the nozzle array in the return path for each sub-pattern. The plurality of sub-patterns formed by changing may be included.
In such a case, the Bi-D adjustment pattern forming process can be efficiently performed.
[0014]
In addition, a plurality of the nozzle rows that discharge liquids of different colors are provided, and the color of the liquid that is discharged from the nozzle rows of the plurality of correction patterns that are executed in parallel is the plurality of the colors It may be different for each correction pattern.
In such a case, since it becomes more important to form a plurality of the correction patterns and perform the shift correction for each correction pattern, the above-described effect, that is, the Bi-D adjustment pattern formation process is performed. The effect that it becomes possible to perform efficiently will be exhibited more notably.
[0015]
Further, a correction pattern group formed of correction patterns equal to the number of the nozzle rows formed for each nozzle row is formed, and at least two correction patterns constituting the correction pattern group are formed. For the above, the operations may be performed in parallel.
In this way, Bi-D adjustment can be performed thoroughly.
[0016]
In addition, all or some of the correction patterns constituting the correction pattern group have dots of the same color formed in an overlapping manner, and the correction pattern constituting the correction pattern group is the same color. When the dots are grouped on the basis of the number of times the dots are overlaid, the plurality of correction patterns that are executed in parallel may belong to the same group.
In this way, it is possible to avoid executing different correction pattern forming operations in parallel, and the correction pattern forming process for correcting the shift of the dot formation position is performed more efficiently. .
[0017]
The correction pattern in which the liquid color is black, the correction pattern in which the liquid color is cyan, and the correction pattern in which the liquid color is magenta belong to the same group, The correction pattern in which the liquid color is a yellow color and the correction pattern in which the liquid color is a light black color belong to the same group, and the correction color in which the liquid color is a light cyan color, The correction pattern whose liquid color is light magenta may belong to the same group.
In this way, highly accurate misalignment correction becomes possible.
[0018]
The correction pattern group includes correction patterns having different dot resolutions in the nozzle row direction, and the correction patterns constituting the correction pattern group are divided into a plurality of groups based on the dot resolution. When grouped, a plurality of correction patterns that are executed in parallel may belong to the same group.
In this way, it is possible to avoid executing different correction pattern forming operations in parallel, and the correction pattern forming process for correcting the shift of the dot formation position is performed more efficiently. .
[0019]
In addition, a correction pattern in which the liquid color is cyan, a correction pattern in which the liquid color is magenta, a correction pattern in which the liquid color is yellow, and the liquid color are light The correction pattern in black color, the correction pattern in which the liquid color is light cyan, and the correction pattern in which the liquid color is light magenta belong to the same group. It may be a group different from the group to which the correction pattern whose color is black belongs.
In this way, highly accurate misalignment correction becomes possible.
[0020]
A correction pattern including a plurality of sub-patterns having different densities, the nozzle array including nozzles for forming dots on the medium by ejecting liquid; A liquid that forms a plurality of correction patterns for correcting deviations in dot formation positions in the intersecting direction intersecting the nozzle row direction on the medium by discharging the liquid from the nozzle row based on the difference in density. In the ejection apparatus, the operation for forming the correction pattern is performed in parallel for the plurality of correction patterns, and has density reading means for reading the density of the sub-pattern, and the density reading means performs the sub-scanning operation. The density of the pattern is read, the deviation is corrected based on the read density information, and includes a plurality of nozzle rows, and the correction pattern includes a plurality of the correction patterns. The dot formation position in the intersecting direction of the dots formed by discharging the liquid from the first nozzle row in the nozzle row and the liquid is discharged from another second nozzle row different from the first nozzle row. A correction pattern for correcting misalignment between the dots formed in the intersecting direction of the dots and the dots formed by ejecting the liquid from the first nozzle row and the liquid from the second nozzle row. And formed by changing the difference between the timing at which liquid is ejected from the first nozzle row and the timing at which liquid is ejected from the second nozzle row for each sub-pattern. A plurality of the correction patterns in which the operations are performed in parallel, the three or more nozzle rows discharging liquids of different colors. One nozzle The color of the liquid ejected from the plurality of correction patterns is the same, and the color of the liquid ejected from the second nozzle array differs for each of the plurality of correction patterns, and three or more nozzle arrays A correction composed of a number of correction patterns obtained by subtracting 1 from the number of nozzle rows, wherein one of the nozzle rows is the first nozzle row and each of the remaining nozzle rows is the second nozzle row. For at least two correction patterns forming the correction pattern group and constituting the correction pattern group, the operation is performed in parallel, and all or a part of the correction patterns forming the correction pattern group Has dots of the same color formed in an overlapping manner, and the correction patterns constituting the correction pattern group are grouped into a plurality of groups based on the number of times the same color dots are superimposed. A plurality of correction patterns in which the operations are executed in parallel belong to the same group, and a correction pattern in which the liquid color is black and a correction in which the liquid color is cyan The correction pattern and the correction pattern in which the color of the liquid is magenta belong to the same group, the correction pattern in which the color of the liquid is yellow, and the correction pattern in which the color of the liquid is a light black color The liquid ejection is characterized in that the pattern belongs to the same group, and the correction pattern in which the liquid color is light cyan and the correction pattern in which the liquid color is light magenta belong to the same group. An apparatus is also feasible.
In this way, the object of the present invention can be achieved more effectively because most of the effects described above can be achieved.
[0021]
Next, a correction pattern having a plurality of sub-patterns having different densities is obtained by a liquid ejection apparatus having a nozzle row in which nozzles for ejecting liquid to form dots on a medium are arranged in a row. Then, a correction pattern for correcting the deviation of the dot formation position in the intersecting direction that intersects the direction of the nozzle row based on the difference in the density of the sub-pattern is discharged from the nozzle row by discharging the liquid. A correction pattern forming method for forming a plurality of correction patterns on a medium, wherein the operation for forming the correction patterns is executed in parallel for the plurality of correction patterns.
According to such a correction pattern forming method, it is possible to efficiently perform the correction pattern forming process for correcting the shift of the dot formation position.
[0022]
Further, a computer, a display device connectable to the computer, and a liquid ejection device connectable to the computer, a nozzle row in which nozzles for ejecting liquid to form dots on a medium are arranged in a row, A correction pattern including a plurality of sub-patterns having different densities, and correcting a deviation in dot formation positions in the intersecting direction intersecting the nozzle row direction based on the difference in density of the sub-patterns. A liquid ejecting apparatus for ejecting the liquid from the nozzle row to form a plurality of correction patterns for forming the correction pattern on the medium, wherein the operation of forming the correction pattern is performed in parallel for the plurality of correction patterns. A liquid discharge system including a liquid discharge device to be executed can also be realized.
The liquid ejection system thus realized is a system that is superior to conventional systems as a whole system.
[0023]
=== Outline of the printer ===
First, an outline of the printer will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic configuration diagram of a printing system including an inkjet printer 22 (hereinafter also referred to as a printer). FIG. 2 is a block diagram illustrating a configuration of the printer 22 as an example of a liquid ejection apparatus centering on the control circuit 40.
[0024]
The printer 22 has a sub-scan feed mechanism that feeds print paper P as an example of a medium by a paper feed motor 23, and a main scan feed mechanism that reciprocates the carriage 31 in the axial direction of the platen 26 by a carriage motor 24. Yes. Here, the feed direction of the printing paper P by the sub-scan feed mechanism is called a sub-scan direction, and the moving direction of the carriage 31 by the main scan feed mechanism is called a main scan direction. The carriage 31 is provided with a reflection type optical sensor 29 that forms density reading means for a correction pattern, which will be described later.
[0025]
In addition, the printer 22 drives a discharge head 60 mounted on the carriage 31 to control discharge of ink as an example of liquid and dot formation, a paper feed motor 23, a carriage motor 24, and a discharge head 60. And a control circuit 40 that controls the exchange of signals with the reflective optical sensor 29 and the operation panel 32. The control circuit 40 is connected to the computer 90 via the connector 56. The computer 90 is equipped with a driver for the printer 22, accepts user commands by operating a keyboard or mouse as input means, and presents various information in the printer 22 to the user by display on the display screen. Has an interface.
[0026]
The sub-scan feed mechanism that transports the printing paper P includes a gear train (not shown) that transmits the rotation of the paper feed motor 23 to the platen 26 and a paper transport roller (not shown). The main scanning feed mechanism for reciprocating the carriage 31 is an endless drive belt 36 between the carriage motor 24 and a slide shaft 34 that is installed in parallel with the axis of the platen 26 and slidably holds the carriage 31. And a position detection sensor 39 for detecting the origin position of the carriage 31.
[0027]
As shown in FIG. 2, the control circuit 40 is configured as an arithmetic logic circuit including a CPU 41, a programmable ROM (PROM) 43, a RAM 44, and a character generator (CG) 45 storing a dot matrix of characters. ing. The control circuit 40 further includes an I / F dedicated circuit 50 dedicated to interface with an external motor and the like, and a head drive connected to the I / F dedicated circuit 50 to drive the ejection head 60 and eject ink. A circuit 52, a motor drive circuit 54 for driving the paper feed motor 23 and the carriage motor 24, and a control circuit 53 for controlling the reflection type optical sensor are provided. The I / F dedicated circuit 50 incorporates a parallel interface circuit and can receive a print signal PS supplied from the computer 90 via the connector 56.
A paper feeding operation for supplying the printing paper P to the printer 22 and a paper discharging operation for discharging the printing paper P from the color inkjet printer 22 are also performed using the paper feed roller 23.
[0028]
=== Configuration Example of Reflective Optical Sensor ===
Next, a configuration example of the reflective optical sensor will be described with reference to FIG. FIG. 3 is a schematic diagram for explaining an example of the reflective optical sensor 29.
[0029]
The reflective optical sensor 29 is attached to the carriage 31, and includes a light emitting unit 29a configured by a light emitting diode that emits white light, for example, and a light receiving unit 29b configured by, for example, a phototransistor. Light emitted from the light emitting unit 29a, that is, incident light is reflected by the printing paper P, and the reflected light is received by the light receiving unit 29b and converted into an electrical signal. The magnitude of the electrical signal is measured as the output value of the light receiving sensor corresponding to the intensity of the received reflected light. Therefore, the reflective optical sensor 29 functions as a density reading unit that reads the density of the pattern on the printing paper P.
[0030]
In the above description, as shown in the figure, the light emitting unit 29a and the light receiving unit 29b are integrated to form a device called the reflective optical sensor 29. However, like the light emitting device and the light receiving device, respectively. A separate device may be configured.
In the above, in order to obtain the intensity of the received reflected light, the magnitude of the electric signal is measured after converting the reflected light into an electric signal. However, the present invention is not limited to this. It is only necessary to measure the output value of the light receiving sensor according to the intensity of the reflected light.
[0031]
=== Configuration of Discharge Head ===
Next, the configuration of the ejection head will be described with reference to FIGS. 4, 5, and 6. FIG. 4 is an explanatory diagram showing a schematic configuration inside the ejection head 60. FIG. 5 is an explanatory diagram showing in detail the structure of the piezo element PE and the nozzle Nz. FIG. 6 is an explanatory diagram showing the arrangement of the nozzles Nz in the ejection head 60.
[0032]
The carriage 31 (FIG. 1) includes a cartridge 71a for black (K) ink, a cartridge 71b for light black (LK) ink, a cartridge 71c for cyan (C) ink, and a light cyan (LC) ) An ink cartridge 71d, a magenta (M) ink cartridge 71e, a light magenta (LM) ink cartridge 71f, and a yellow (Y) ink cartridge 71g can be mounted.
[0033]
A discharge head 60 is provided below the carriage 31, and the discharge head 60 is composed of a total of seven discharge heads 60a, 60b, 60c, 60d, 60e, 60f, and 60g for each color. At the bottom of the carriage 31, there are provided introduction pipes 67 (see FIG. 4) for guiding ink from the ink tanks to the discharge heads 60a, 60b, 60c, 60d, 60e, 60f, and 60g for each color. When the cartridges 71a, 71b, 71c, 71d, 71e, 71f, 71g are mounted on the carriage 31 from above, an introduction tube 67 is inserted into a connection hole provided in each cartridge, and each color discharge head 60a, 60b, Ink can be supplied to 60c, 60d, 60e, 60f, and 60g.
[0034]
When the cartridges 71 a, 71 b, 71 c, 71 d, 71 e, 71 f, 71 g are mounted on the carriage 31, the ink in the cartridge is sucked out via the introduction pipe 67 as shown in FIG. Further, the ink is guided to the discharge heads 60a, 60b, 60c, 60d, 60e, 60f, and 60g for each color.
[0035]
Each color ejection head 60a, 60b, 60c, 60d, 60e, 60f, 60g provided at the lower part of the carriage 31 is provided with a piezoelectric element PE that is one of electrostrictive elements and excellent in responsiveness for each nozzle Nz. Is arranged. As shown in the upper part of FIG. 5, the piezo element PE is installed at a position in contact with the ink passage 68 that guides ink to the nozzle Nz. As is well known, the piezo element PE is an element that transforms electro-mechanical energy at a very high speed because the crystal structure is distorted by application of voltage. In the present embodiment, by applying a voltage having a predetermined time width between the electrodes provided at both ends of the piezo element PE, the piezo element PE expands for the voltage application time as shown in the lower part of FIG. One side wall of 68 is deformed. As a result, the volume of the ink passage 68 contracts according to the expansion of the piezo element PE, and the ink corresponding to the contraction becomes an ink droplet Ip and is ejected from the tip of the nozzle Nz at high speed. The ink droplet Ip soaks into the printing paper P mounted on the platen 26, whereby dots are formed and printing is performed.
[0036]
As shown in FIG. 6, the ejection head 60 includes a black nozzle row, a light black nozzle row, a cyan nozzle row, a light cyan nozzle row, a magenta nozzle row, and a light magenta nozzle row that are arranged on a straight line along the sub-scanning direction. , And yellow nozzle row. Each nozzle row includes 180 nozzles # 1 to # 180, and the nozzles # 1 to # 180 are arranged at a constant nozzle pitch k · D along the sub-scanning direction. Here, D is the dot pitch in the sub-scanning direction, and k is an integer. Hereinafter, the integer k representing the nozzle pitch k · D is simply referred to as “nozzle pitch k”. In the example of FIG. 6, the nozzle pitch k is 4 dots. However, the nozzle pitch k can be set to an arbitrary integer.
[0037]
The head length of the ejection head 60 in the sub-scanning direction is about 1 inch.
The reflective optical sensor 29 described above is attached to the carriage 31 together with the ejection head 60. In the present embodiment, as shown in the drawing, the position of the reflective optical sensor 29 in the sub-scanning direction is This coincides with the position of the nozzle # 1 in the sub-scanning direction.
Further, the moving direction of the carriage 31 by the above-described main scanning feed mechanism, that is, the main scanning direction intersects with the nozzle row direction.
[0038]
The printer 22 having the hardware configuration described above transports the printing paper P by the paper feed motor 23, reciprocates the carriage 31 by the carriage motor 24, and simultaneously drives the piezo elements PE of the ejection heads 60, so that each color Ink is ejected to form dots and form a multicolor image on the printing paper P.
[0039]
Here, as described above, the printer 22 having the head for ejecting ink using the piezo element PE is used. However, various ejection drive elements other than the piezo element can be used. It is. For example, the present invention can be applied to a printer provided with an ejection drive element of a type that energizes a heater arranged in an ink passage and ejects ink by bubbles generated in the ink passage. The configuration of the control circuit 40 also supplies a drive signal to each ejection drive element, and generates a drive signal so that the ejection order of ink droplets with time is kept the same in the forward and backward passes of main scanning. Anything can be used.
[0040]
=== Driving Head Drive ===
Next, driving of the ejection head 60 will be described with reference to FIG. FIG. 7 is a block diagram showing a configuration of a drive signal generator provided in the head drive circuit 52 (FIG. 2).
In FIG. 7, the drive signal generation unit includes a plurality of mask circuits 204, an original drive signal generation unit 206, and a drive signal correction unit 230. The mask circuit 204 is provided corresponding to a plurality of piezo elements PE for driving the nozzles n1 to n180 of the ejection head 61a. In FIG. 7, the number in parentheses at the end of each signal name indicates the number of the nozzle to which the signal is supplied. The original drive signal generator 206 generates an original drive signal ODRV that is commonly used for the nozzles n1 to n180. The original drive signal ODRV is a signal including two pulses, a first pulse W1 and a second pulse W2, within the main scanning period for one pixel. The drive signal correction unit 230 performs correction by shifting the timing of the drive signal waveform shaped by the mask circuit 204 back and forth. By correcting the timing of the drive signal waveform, the deviation of the dot formation position in the main scanning direction is corrected.
In the present embodiment, the drive generation signal section provided in the head drive circuit 52 (FIG. 2) shown in FIG. 7 is provided for each nozzle row.
[0041]
=== Correction Pattern for Correcting Misalignment of Dot Forming Position in Main Scanning Direction ===
Next, an outline of a correction pattern for correcting a shift in dot formation position in the main scanning direction will be described with reference to FIG. FIG. 8 is a diagram for explaining an outline of a correction pattern for correcting a shift in dot formation position in the main scanning direction.
[0042]
In the present embodiment, as an example of a correction pattern for correcting a shift in dot formation position in the main scanning direction, the first nozzle row (here, the nozzle row is a black nozzle) among the plurality of nozzle rows described above. Main scanning of dots formed by ejecting ink from other second nozzle rows different from the first nozzle row, and dot forming positions in the main scanning direction of dots formed by ejecting ink from the first nozzle row A correction pattern for correcting misalignment with the dot formation position in the direction (in this embodiment, this correction is also referred to as Uni-D adjustment), and ink is formed by ejecting ink from the nozzle row in the main scanning forward path. The deviation between the dot formation position in the main scanning direction and the dot formation position in the main scanning direction of dots formed by ejecting ink from the nozzle row in the return path is corrected (actual In the embodiment, the correction is also referred to as Bi-D adjustment) for the correction pattern for explaining.
[0043]
<<< Uni-D adjustment pattern >>>
The Uni-D adjustment pattern has, for example, 11 sub-patterns P1 to P11 as shown in the upper diagram of FIG. Each of the sub-patterns P1 to P11 moves the ejection head 28 in the main scanning direction, and in the meantime, the first nozzle row (for example, the nozzle of the black nozzle row) and another second nozzle row different from the first nozzle row Thus, dots are formed on the printing paper P and printed.
[0044]
For the first nozzle row, ink droplets are ejected onto the printing paper P at the same interval (= 1/180 inch). On the other hand, for the second nozzle row, ink droplets are similarly ejected at the same interval (= 1/180 inch), but the ejection timing is changed for each of the sub-patterns P1 to P11, and the change is made in the main scanning direction. Print in line so that the amount changes sequentially. That is, the difference between the timing at which ink is ejected from the first nozzle row and the timing at which ink is ejected from the second nozzle row is different for each of the sub-patterns P1 to P11.
[0045]
The amount of change in the ejection timing for the second nozzle row is the amount of deviation between the dots formed by the first nozzle row and the dots formed by the second nozzle row by a unit amount temporarily set to select a correction value. Is set to change. Here, the unit amount is set to a distance obtained by dividing the ideal inter-dot distance (= 1/180 inch) in the main scanning direction into, for example, eight equal parts, that is, (1/180 inch) ÷ 8 = 1/1440 inch. The sub-patterns P1 to P11 are formed by shifting the discharge timing for the second nozzle row so as to be shifted by the unit amount. That is, the sub-patterns P1 to P11 are formed by changing the difference between the timing of ejecting ink from the first nozzle row and the timing of ejecting ink from the second nozzle row for each sub-pattern according to the correction value. Has been.
[0046]
For example, regarding the sub-pattern P1 and the sub-pattern P2, the difference between the discharge timing for the first nozzle row and the discharge timing for the second nozzle row in the sub-pattern P1 is ΔP1, and the first nozzle in the sub-pattern P2 When the difference between the discharge timing for the row and the discharge timing for the second nozzle row is ΔP2, | ΔP1−ΔP2 | = 1/1440 inches.
[0047]
In the sub-patterns P1 to P11 formed in this manner, the overlap between the dots formed on the printing paper P by the first nozzle row and the dots formed on the printing paper P by the second nozzle row is larger. The density of the sub-pattern decreases, and the smaller the overlap between the dots formed on the printing paper P by the first nozzle row and the dots formed on the printing paper P by the second nozzle row, the lower the sub-pattern density. It becomes darker. That is, the Uni-D adjustment pattern has a plurality of sub-patterns having different densities. The lower diagram of FIG. 8 shows the darkness of each sub-pattern by the mark ●, and is shown by a curve by interpolation based on the data of the mark ●. In the correction pattern shown in the upper diagram of FIG. The density is the lowest in the sub-pattern P6, and the density is the highest in the sub-pattern P2 and the sub-pattern P10.
[0048]
<<< Bi-D adjustment pattern >>>
As shown in the upper diagram of FIG. 8, the Bi-D adjustment pattern has, for example, 11 sub patterns P1 to P11. Each of the sub-patterns P1 to P11 is printed by causing the ejection head 28 to reciprocate in the main scanning direction and forming dots on the printing paper P with nozzles in a specific row (for example, nozzles in a black nozzle row) during that time. is there.
[0049]
In the forward path, ink droplets are ejected onto the printing paper P at the same interval (= 1/180 inch). On the other hand, in the return path, ink droplets are similarly ejected at the same interval (= 1/180 inch), but the ejection timing is changed for each of the sub-patterns P1 to P11, and the amount of change is sequentially increased in the main scanning direction. Print side by side to change. That is, the difference between the timing at which ink is ejected from the nozzle array in the forward path and the timing at which ink is ejected from the nozzle array in the backward path is different for each of the sub-patterns P1 to P11.
[0050]
The amount of change in the ejection timing in the return pass is set so that the amount of deviation between the forward pass dot and the return pass dot changes by a unit amount temporarily set for selecting a correction value. Here, the unit amount is set to a distance obtained by dividing the ideal inter-dot distance (= 1/180 inch) in the main scanning direction into, for example, eight equal parts, that is, (1/180 inch) ÷ 8 = 1/1440 inch. The sub-patterns P1 to P11 are formed by shifting the discharge timing of the return path so as to shift by the unit amount. That is, the sub-patterns P1 to P11 change the difference between the timing of ejecting ink from the nozzle row in the main scanning forward path and the timing of ejecting ink from the nozzle row in the backward path for each sub-pattern according to the correction value. Is formed.
[0051]
For example, regarding the sub-pattern P1 and the sub-pattern P2, the difference between the forward ejection timing and the backward ejection timing in the sub-pattern P1 is ΔP1, and the forward ejection timing and the backward ejection timing in the sub-pattern P2 are When the deviation is ΔP2, | ΔP1−ΔP2 | = 1/1440 inch.
[0052]
In the subpatterns P1 to P11 formed in this way, the larger the overlap between the dots formed on the printing paper P in the forward path and the dots formed on the printing paper P in the backward path, the larger the subpattern. The density becomes lighter. The smaller the overlap between the dots formed on the printing paper P in the forward path and the dots formed on the printing paper P in the backward path, the higher the density of the sub-pattern. That is, the Bi-D adjustment pattern has a plurality of sub-patterns having different densities. The lower diagram of FIG. 8 shows the darkness of each sub-pattern by the mark ●, and is shown by a curve by interpolation based on the data of the mark ●. In the correction pattern shown in the upper diagram of FIG. The density is the lowest in the sub-pattern P6, and the density is the highest in the sub-pattern P2 and the sub-pattern P10.
[0053]
=== Method for correcting misalignment of dot formation position in main scanning direction using correction pattern ===
In the present embodiment, the density of each sub-pattern shown in the upper diagram of FIG. 8 is read by the reflective optical sensor 29 and converted into an electrical signal, and the sub-pattern with the lightest density is based on the electrical signal as density information. Is extracted by the control circuit 40. As described above, the dots formed on the printing paper P by the first nozzle row (or in the forward path) and the dots formed on the printing paper P by the second nozzle row (or in the backward path) The greater the overlap, the lighter the density of the sub-pattern, so the correction value corresponding to the sub-pattern with the lowest density is the desired correction value. Therefore, the correction value corresponding to the sub-pattern with the lowest density is acquired as the correction value for correcting the deviation of the dot formation position in the main scanning direction. When printing is performed later, the correction value is input to the drive signal correction unit 230 described above, and the shift is corrected. In other words, in the printing procedure executed later, from the second nozzle row at the ink discharge timing for the second nozzle row (or in the return path) when the sub-pattern having the lightest density is formed in the correction pattern forming procedure. (Or on the return path).
[0054]
=== Procedure for Forming Correction Pattern ===
Next, with reference to FIGS. 9 to 14, the procedure of the correction pattern forming process will be described by taking two embodiments as examples. FIG. 9 is a flowchart for explaining a procedure according to the first embodiment of the correction pattern forming process. 10A to 10C are schematic diagrams according to the first embodiment showing the positional relationship between the nozzle array and the printing paper P when the correction pattern forming process is performed. FIG. 11 is a diagram according to the first embodiment showing the paper feed amount and the used nozzles when the correction pattern forming process is performed. FIG. 12 is a flowchart for explaining a procedure according to the second embodiment of the correction pattern forming process. 13A to 13C are schematic diagrams according to the second embodiment showing the positional relationship between the nozzle row and the printing paper P when the correction pattern forming process is performed. FIG. 14 is a diagram according to the second embodiment showing the paper feed amount and the used nozzles when the correction pattern forming process is performed.
[0055]
In the present embodiment, in the case of Uni-D adjustment, of the seven nozzle rows described above, the black nozzle row is the first nozzle row, and each of the remaining nozzle rows is the second nozzle row. A plurality of the correction patterns (in this specification, a pattern group including the plurality of correction patterns is also referred to as a correction pattern group) is formed on the printing paper P. In the case of Bi-D adjustment, a plurality of the correction patterns for each of the seven nozzle arrays described above (in this specification, a pattern group including a plurality of correction patterns is also referred to as a correction pattern group). ) On the printing paper P. That is, in the case of Uni-D adjustment, six correction patterns are formed, and in the case of Bi-D adjustment, seven correction patterns are formed. In the following description, for convenience, a correction pattern formed by ejecting ink from a black nozzle row and a yellow nozzle row (only the yellow nozzle row in the case of Bi-D adjustment) is referred to as a yellow correction pattern, a black nozzle. A correction pattern formed by ejecting ink from a row and a light magenta nozzle row (in the case of Bi-D adjustment, only a light magenta nozzle row) is a light magenta correction pattern, a black nozzle row and a magenta nozzle row (Bi The correction pattern formed by ejecting ink from the -D adjustment (magenta nozzle row only) is the magenta correction pattern, the black nozzle row and the light cyan nozzle row (in the case of Bi-D adjustment, the light cyan nozzle). The correction pattern formed by ejecting ink from the column only) is the light cyan correction pattern. A correction pattern formed by ejecting ink from a black nozzle row and a cyan nozzle row (in the case of Bi-D adjustment, only the cyan nozzle row) is a cyan correction pattern, a black nozzle row and a light black nozzle row (Bi In the case of -D adjustment, the correction pattern formed by ejecting ink from the light black nozzle row only) is the light black correction pattern, and for Bi-D adjustment formed by ejecting ink from the black nozzle row The pattern is called a black correction pattern.
[0056]
<<<< first embodiment >>>>
The printer 22 forms a correction pattern by driving the ejection head 60, the carriage motor 24, and the paper feed motor 23 by the head drive circuit 52 and the motor drive circuit 54.
First, as shown in FIG. 10A, the printer 22 ejects ink while moving the ejection head 60 to form a light magenta correction pattern and a light cyan correction pattern (step S2). Next, after feeding the printing paper P, the printer 22 ejects ink while moving the ejection head 60 to form a yellow correction pattern and a light black correction pattern, as shown in FIG. S4). Next, after feeding the printing paper P, the printer 22 ejects ink while moving the ejection head 60, as shown in FIG. 10C, and a magenta correction pattern, a cyan correction pattern, and Bi-D. In the case of adjustment, a black correction pattern is formed (step S6).
[0057]
As described above, in the present embodiment, each of the plurality of correction patterns is not formed one by one while inserting the paper feed, but the operation of forming the correction patterns is performed by the plurality of correction patterns. The correction patterns are formed by executing the correction patterns in parallel. That is, in the above, the operation for forming the correction pattern is executed in parallel for the light magenta correction pattern and the light cyan correction pattern, and is executed in parallel for the yellow correction pattern and the light black correction pattern. In the case of the correction pattern, cyan correction pattern, and Bi-D adjustment, the black correction pattern is executed in parallel to form a correction pattern.
[0058]
Further, as apparent from the above, in the present embodiment, in the case of Uni-D adjustment, the first nozzle row of the plurality of correction patterns in which the operation for forming the correction pattern is executed in parallel. The color of ink ejected from the same is the same for the plurality of correction patterns (in this embodiment, the black color), and the color of ink ejected from the second nozzle array is the same for each of the plurality of correction patterns. Is different. Further, in the case of Bi-D adjustment, the color of ink ejected from the nozzle row of a plurality of correction patterns in which operations for forming correction patterns are performed in parallel is set for each of the plurality of correction patterns. Is different.
[0059]
10A to 10C show an example of Bi-D adjustment for easy understanding of the drawings. That is, in the Uni-D adjustment, as described above, ink is ejected from the black nozzle row in any correction pattern, but such matters are not shown in FIGS. 10A to 10C. Yes. In the Uni-D adjustment, the black correction pattern is not formed.
[0060]
In the present embodiment, the operation for forming the correction pattern is performed in parallel for at least two correction patterns (for example, the light magenta correction pattern and the light cyan correction pattern) constituting the correction pattern group described above. Is running.
[0061]
Next, the correction pattern formation processing procedure will be discussed in more detail with reference to FIG. 11 while paying attention to the paper feed amount, the used nozzle row, and the like.
[0062]
FIG. 11 shows the paper feed amount (unit: nozzle pitch), accumulated paper feed amount (unit: nozzle pitch), nozzles to be used, and corresponding step numbers for each correction pattern to be formed.
[0063]
The cumulative paper feed amount is the cumulative paper feed amount based on the time when the first correction pattern was formed when each correction pattern was formed. The paper feed amount was the time when each correction pattern was formed. This is the paper feed amount based on the previous correction pattern formation.
In the column of used nozzles, the numbers of the nozzles used for forming each correction pattern are shown. As is apparent from the figure, the operation for forming the correction pattern is executed in parallel for the two correction patterns. In this case, nozzles # 47 to # 90 and nozzles # 91 to 134, that is, 44 × 2 nozzles are used, and when the correction patterns are executed in parallel, the nozzles # 25 to # 25 are used. # 68, nozzles # 69 to 112, and nozzles # 113 to 156, that is, 44 × 3 nozzles are used.
[0064]
The corresponding step number column shows the step number in the flowchart of FIG.
Here, the number of times is expressed in square brackets in the column of the correction pattern to be formed. This is because the light magenta correction pattern and light cyan correction pattern formation (step S2), the yellow correction pattern and the light black are formed. In the correction pattern formation (step S4), it means that dots of the same color are overprinted.
[0065]
For example, when forming a light magenta correction pattern and a light cyan correction pattern, the printer 22 ejects ink while moving the ejection head 60 to form dots, and the light magenta correction pattern and the light cyan correction pattern. Perform the first printing. Next, without feeding the printing paper P, the printer 22 ejects ink at the same timing as the first printing while moving the ejection head 60 to place dots at the same dot formation positions as in the first printing. Then, the second printing of the light magenta correction pattern and the light cyan correction pattern is performed. Further, without feeding the printing paper P, the printer 22 ejects ink at the same timing as the first and second printing while moving the ejection head 60, and the same dots as in the first and second times. Dots are formed at the formation positions, and the third printing of the light magenta correction pattern and the light cyan correction pattern is performed. Note that 0 is written in a part of the paper feed amount column in FIG. 11, which means that paper feed is not performed between the above-mentioned times.
As apparent from FIG. 11, among the correction patterns constituting the correction pattern group described above, the light magenta correction pattern, the light cyan correction pattern, the yellow correction pattern, and the light black correction pattern are as follows. , Dots having the same color formed in an overlapping manner.
[0066]
The correction patterns constituting the correction pattern group are grouped into a plurality of groups based on the number of times the same color dots are superimposed. That is, as shown in FIG. 11, the same color dots are overprinted twice for the light magenta correction pattern and the light cyan correction pattern, and the same color dots are applied once for the yellow correction pattern and the light black correction pattern. Overprinting is not performed for the magenta correction pattern, cyan correction pattern, and black correction pattern (dots of the same color are overprinted 0 times), so the light magenta correction pattern and the light cyan correction pattern Belong to the same group, the yellow correction pattern and the light black correction pattern belong to the same group, and the magenta correction pattern, the cyan correction pattern, and the black correction pattern belong to the same group.
A plurality of correction patterns in which operations for forming correction patterns are performed in parallel belong to the same group.
[0067]
In this embodiment, when the correction pattern is formed, the dot resolution in the sub-scanning direction (hereinafter also simply referred to as dot resolution) is 180 dpi. The dot resolution is not limited to this, and may be, for example, 360 dpi or 720 dpi. When the dot resolution is increased in this way, the head length in the sub-scanning direction is about 1 inch, and the number of nozzles constituting the nozzle row is 180 dots. Therefore, after one correction pattern starts to be formed. It is necessary to insert a paper feeding procedure before the formation is completed. Conversely, this is not necessary when the dot resolution is 180 dpi.
[0068]
<<< Second Embodiment >>>
The printer 22 forms a correction pattern by driving the ejection head 60, the carriage motor 24, and the paper feed motor 23 by the head drive circuit 52 and the motor drive circuit 54.
[0069]
First, as shown in FIG. 13A, the printer 22 ejects ink while moving the ejection head 60 to form a yellow correction pattern, a light magenta correction pattern, and a magenta correction pattern (step S12). . Next, after feeding the printing paper P, as shown in FIG. 13B, the printer 22 ejects ink while moving the ejection head 60, and performs a light cyan correction pattern, a cyan correction pattern, and a light black correction. A pattern for use is formed (step S14). Next, after feeding the printing paper P, the printer 22 forms a black correction pattern in the case of Bi-D adjustment, as shown in FIG. 13C (step S16).
[0070]
As described above, also in the present embodiment, each of the plurality of correction patterns is not formed one by one while inserting the paper feed, but the operation of forming the correction patterns is performed by the plurality of correction patterns. The correction patterns are formed by executing the correction patterns in parallel. That is, in the above, the operation for forming the correction pattern is executed in parallel for the yellow correction pattern, the light magenta correction pattern, and the magenta correction pattern, and the light cyan correction pattern, the cyan correction pattern, and The light black correction pattern is executed in parallel to form a correction pattern.
[0071]
Further, as apparent from the above, in the present embodiment, in the case of Uni-D adjustment, the first nozzle row of the plurality of correction patterns in which the operation for forming the correction pattern is executed in parallel. The color of ink ejected from the same is the same for the plurality of correction patterns (in this embodiment, the black color), and the color of ink ejected from the second nozzle array is the same for each of the plurality of correction patterns. Is different. Further, in the case of Bi-D adjustment, the color of ink ejected from the nozzle row of a plurality of correction patterns in which operations for forming correction patterns are performed in parallel is set for each of the plurality of correction patterns. Is different.
[0072]
13A to 13C also show an example of Bi-D adjustment for easy understanding of the drawing. That is, in the Uni-D adjustment, as described above, ink is ejected from the black nozzle row in any correction pattern, but such matters are not shown in FIGS. 13A to 13C. Yes. In the Uni-D adjustment, the black correction pattern is not formed.
Further, in the present embodiment, correction patterns for at least two correction patterns (for example, a yellow correction pattern, a light magenta correction pattern, and a magenta correction pattern) constituting the correction pattern group described above are used. The operations to form are performed in parallel.
[0073]
Next, the correction pattern formation processing procedure will be discussed in more detail with reference to FIG. 14 while paying attention to the paper feed amount, the used nozzle row, and the like.
FIG. 14 shows the paper feed amount (unit: nozzle pitch), accumulated paper feed amount (unit: nozzle pitch), nozzle to be used, and corresponding step number for each correction pattern to be formed.
[0074]
The cumulative paper feed amount is the cumulative paper feed amount based on the time when the first correction pattern was formed when each correction pattern was formed. The paper feed amount was the time when each correction pattern was formed. This is the paper feed amount based on the previous correction pattern formation.
In the column of used nozzles, the numbers of the nozzles used for forming each correction pattern are shown. As is apparent from the figure, the operation for forming the correction pattern is executed in parallel for one correction pattern. In this case, nozzles # 69 to 112, that is, 44 nozzles are used, and when executed in parallel for three correction patterns, nozzles # 25 to # 68, nozzles # 69 to 112, and Nozzles # 113 to 156, that is, 44 × 3 nozzles are used.
[0075]
The corresponding step number column represents the step number in the flowchart of FIG.
Here, the number of times is expressed in square brackets in the column of the correction pattern to be formed, which means that dots are formed with a dot resolution finer than 180 dpi when forming the correction pattern. . That is, in the first embodiment, the dot resolution is 180 dpi, but in this embodiment, the dot resolution is 360 dpi when the black correction pattern is formed (step S16), and the others. When the correction pattern is formed (step S12 and step S14), it is set to 720 dpi.
As described above, when the dot resolution is increased in this way, the head length in the sub-scanning direction is about 1 inch, and the number of nozzles constituting the nozzle row is 180 dots. It is necessary to insert a paper feeding procedure from the start of pattern formation to the end of pattern formation.
[0076]
For example, when forming a correction pattern with a resolution of 720 dpi, the printer 22 ejects ink while moving the ejection head 60 to print the first correction pattern. Next, the printing paper P is fed by one dot pitch (= 0.25 nozzle pitch), and the printer 22 ejects ink at the same timing as the first printing while moving the ejection head 60. The second correction pattern is printed. Further, the printing paper P is fed by one dot pitch (= 0.25 nozzle pitch), and the printer 22 moves the ejection head 60 while moving the ink at the same timing as the first and second printing. The third pattern of the correction pattern is printed by discharging. Further, the printing paper P is fed by one dot pitch (= 0.25 nozzle pitch), and the printer 22 is the same as the first, second, and third printing while moving the ejection head 60. Ink is ejected at the timing, and the fourth printing of the correction pattern is performed. Further, when the correction pattern is formed with a resolution of 360 dpi, the paper feed amount may be two dot pitches (= 0.5 nozzle pitch), and printing may be performed twice.
[0077]
As is apparent from FIG. 14, the correction pattern group described above includes correction patterns having different dot resolutions.
Moreover, the correction patterns constituting the correction pattern group are grouped into a plurality of groups based on the dot resolution. That is, since the dot resolution is 360 dpi when forming the black correction pattern and 720 dpi when forming the other correction patterns, the correction patterns other than the black correction pattern are in the same group. This group is a group different from the group to which the black correction pattern belongs.
A plurality of correction patterns in which operations for forming correction patterns are performed in parallel belong to the same group.
As described above, the operation of forming the correction pattern is executed in parallel for a plurality of correction patterns, thereby efficiently performing the correction pattern forming process for correcting the deviation of the dot formation position. Is possible.
[0078]
That is, as explained in the section of the problem to be solved by the invention, in the procedure of forming a plurality of correction patterns, each of the correction patterns is formed one by one while inserting paper feed. The procedure is inefficient.
Therefore, as described above, if the operation of forming the correction pattern is executed in parallel for a plurality of correction patterns, the time required for forming the plurality of correction patterns is shortened. The correction pattern forming process for correcting the deviation of the dot formation position is efficiently performed.
[0079]
=== Other Embodiments ===
As mentioned above, although the liquid discharge apparatus etc. which concern on this invention have been demonstrated based on one Embodiment, Embodiment mentioned above is for making an understanding of this invention easy, and limits this invention. is not. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof.
Further, although the printing paper has been described as an example of the medium, a film, a cloth, a thin metal plate, or the like may be used as the medium.
[0080]
In the above-described embodiment, an ink jet printer has been described as an example of a liquid ejection device, but the present invention is not limited to this. For example, color filter manufacturing apparatus, dyeing apparatus, fine processing apparatus, semiconductor manufacturing apparatus, surface processing apparatus, three-dimensional modeling machine, liquid vaporizer, organic EL manufacturing apparatus (particularly polymer EL manufacturing apparatus), display manufacturing apparatus, film formation You may apply the same technique as this embodiment to an apparatus, a DNA chip manufacturing apparatus, etc. Even if the present technology is applied to such a field, since the liquid can be ejected toward the medium, the above-described effects can be maintained.
[0081]
In the above embodiment, a color ink jet printer has been described as an example of an ink jet printer. However, the present invention is not limited to this, and can be applied to, for example, a monochrome ink jet printer.
[0082]
In the above embodiment, ink has been described as an example of a liquid, but the present invention is not limited to this. For example, a liquid (including water) containing a metal material, an organic material (particularly a polymer material), a magnetic material, a conductive material, a wiring material, a film forming material, a processing solution, a gene solution, or the like may be discharged from a nozzle. .
[0083]
Further, the above-described misalignment correction may be performed based on a user's request, may be performed automatically without a user instruction, or before the printer reaches the user's hand, for example, at the time of shipment. Etc. may be performed.
[0084]
In the above-described embodiment, a reflection type optical sensor is provided as a density reading unit for reading the density of the sub-pattern, and the density of the sub-pattern is read by the reflection type optical sensor, and the read density information is obtained. However, the present invention is not limited to this, and density information for correcting the deviation may be acquired by other means.
However, the above embodiment is more preferable in that density information for correcting deviation can be easily obtained.
[0085]
In the above-described embodiment, the correction pattern includes a plurality of nozzle rows, and the correction pattern is a dot in the intersecting direction of dots formed by ejecting ink from the first nozzle row of the plurality of nozzle rows. It is a correction pattern for correcting a deviation between a formation position and a dot formation position in the intersecting direction of dots formed by ejecting ink from another second nozzle row different from the first nozzle row. And dots formed by ejecting ink from the first nozzle array, and dots formed by ejecting ink from the second nozzle array, and ejecting ink from the first nozzle array The plurality of sub-patterns formed by changing the difference between the timing of performing the ink ejection and the timing of ejecting ink from the second nozzle row for each sub-pattern. Not intended to be.
However, in such a case, the Uni-D adjustment pattern formation process can be performed efficiently.
[0086]
Further, in the above-described embodiment, three or more nozzle arrays that eject inks of different colors are provided, and the plurality of correction patterns that are executed in parallel are ejected from the first nozzle array. The color of the ink to be applied is the same for the plurality of correction patterns, and the color of the ink ejected from the second nozzle row is different for each of the plurality of correction patterns, but is not limited thereto. is not. For example, the color of the ink ejected from the second nozzle row may be the same in the plurality of correction patterns.
However, when the color of the ink ejected from the second nozzle row is different for each of the plurality of correction patterns, a plurality of the correction patterns are formed and each of the correction patterns is compared with the case where they are the same. The importance of correcting deviation increases. Therefore, the above-described embodiment is more effective in that the effect described above, that is, the effect that the Uni-D adjustment pattern forming process can be efficiently performed can be exhibited more remarkably. Is.
[0087]
In the above embodiment, one of the three or more nozzle rows is defined as the first nozzle row, and each of the remaining nozzle rows is defined as the second nozzle row. A correction pattern group including a number of correction patterns obtained by subtracting 1 is formed, and the operation is performed in parallel for at least two correction patterns constituting the correction pattern group. However, the present invention is not limited to this. For example, it is not always necessary to form a correction pattern group including correction patterns obtained by subtracting 1 from the number of nozzle rows. That is, only a part and a plurality of correction patterns are formed out of the number of correction patterns obtained by subtracting 1 from the number of nozzle rows, and the operations are executed in parallel for the plurality of correction patterns. It is good as well.
However, the above embodiment is more preferable in that the Uni-D adjustment can be performed thoroughly.
[0088]
In the above-described embodiment, the correction pattern includes the dot formation position in the intersecting direction of the dots formed by ejecting ink from the nozzle row in the main scanning forward pass, and the ink from the nozzle row in the return pass. This is a correction pattern for correcting a deviation of the dots formed by ejection from the dot formation position in the intersecting direction, and dots formed by ejecting ink from the nozzle row in the forward path of main scanning, and the return path A dot formed by ejecting ink from the nozzle row at the same time, and a timing at which ink is ejected from the nozzle row in the forward path of main scanning and a timing at which ink is ejected from the nozzle row in the return path The plurality of sub-patterns formed by changing the difference for each sub-pattern, but is not limited thereto. Not.
However, in such a case, the Bi-D adjustment pattern forming process can be efficiently performed.
[0089]
Further, in the above-described embodiment, a plurality of the nozzle arrays that eject inks of different colors are provided, and the ink ejected from the nozzle arrays of the plurality of correction patterns in which the operations are executed in parallel. The color is different for each of the plurality of correction patterns, but is not limited thereto. For example, the color of ink ejected from the nozzle row may be the same for the plurality of correction patterns.
However, when the color of the ink ejected from the nozzle row is different for each of the plurality of correction patterns, a plurality of the correction patterns are formed and the deviation correction is performed for each of the correction patterns, compared to the case where they are the same. The importance of doing is increased. Therefore, the above-described embodiment is more effective in that the above-described effect, that is, the effect that the Bi-D adjustment pattern forming process can be efficiently performed is more significantly exhibited. Is.
[0090]
Further, in the above embodiment, a correction pattern group is formed which is formed for each nozzle row and is composed of the same number of correction patterns as the number of nozzle rows, and the correction pattern group is configured. With respect to at least two correction patterns, the operation is executed in parallel. However, the present invention is not limited to this.
For example, it is not always necessary to form a correction pattern group including a number of correction patterns equal to the number of nozzle rows. That is, only a part and a plurality of correction patterns among the number of correction patterns equal to the number of the nozzle rows may be formed, and the operations may be executed in parallel for the plurality of correction patterns. Good.
However, the above embodiment is more preferable in that Bi-D adjustment can be performed thoroughly.
[0091]
In the above embodiment, all or some of the correction patterns constituting the correction pattern group have dots of the same color formed in an overlapping manner, and constitute the correction pattern group. When the correction patterns to be performed are grouped into a plurality of groups based on the number of times the same color dots are overlaid, the plurality of correction patterns that are executed in parallel belong to the same group. However, the present invention is not limited to this. For example, a plurality of correction patterns in which the above operations are executed in parallel may not belong to the same group.
[0092]
As described above, the operation for forming the correction pattern differs depending on the group to which the correction pattern belongs. Therefore, if a plurality of correction patterns for which correction pattern forming operations are performed in parallel belong to the same group, it is possible to avoid performing different correction pattern formation operations in parallel. The above embodiment is preferable in that the correction pattern forming process for correcting the deviation of the dot formation position can be performed more efficiently.
[0093]
In the above embodiment, the correction pattern in which the ink color is black, the correction pattern in which the ink color is cyan, and the correction pattern in which the ink color is magenta are the same. The correction pattern belonging to the group, the ink color is yellow, and the correction pattern, the ink color being light black, belong to the same group, and the ink pattern is light cyan, Although the correction pattern having the ink color of light magenta belongs to the same group, the invention is not limited to this, and other groupings may be adopted.
[0094]
As described above, when reading the density of the correction pattern, the light emitted from the light emitting portion of the reflective optical sensor, that is, the incident light is reflected by the correction pattern on the printing paper, and the reflected light is reflected by the reflective optical sensor. Is received by the light receiving unit and converted into an electrical signal. In such light reception, it is necessary to secure a sufficient output level difference between adjacent sub-patterns.
[0095]
On the other hand, the obtained output level difference differs depending on the color of the correction pattern. That is, the light color correction pattern has a smaller output level difference than the dark color correction pattern.
Therefore, by increasing the number of overstrikes for lighter color correction patterns, a sufficient output level difference can be ensured, and as a result, highly accurate misalignment correction can be performed.
[0096]
The above grouping is determined from such a viewpoint, and the above embodiment is more preferable in that a highly accurate deviation correction is possible.
Note that the above grouping is not necessarily based on the assumption that there are seven colors of ink. For example, for a printer using four color inks of cyan, magenta, yellow, and black, the group includes a correction pattern in which the ink color is black and a correction in which the ink color is cyan. There are two groups: a group to which the pattern for correction and a correction pattern for which the ink color is magenta belong, and a group to which the correction pattern for which the ink color is yellow belong.
[0097]
In the above embodiment, the correction pattern group includes correction patterns having different dot resolutions in the nozzle row direction, and the correction pattern constituting the correction pattern group is the dot resolution. However, the present invention is not limited to this. However, the present invention is not limited to this. For example, a plurality of correction patterns in which the above operations are executed in parallel may not belong to the same group.
[0098]
As described above, the operation for forming the correction pattern differs depending on the group to which the correction pattern belongs. Therefore, if a plurality of correction patterns for which correction pattern forming operations are performed in parallel belong to the same group, it is possible to avoid performing different correction pattern formation operations in parallel. The above embodiment is preferable in that the correction pattern forming process for correcting the deviation of the dot formation position can be performed more efficiently.
[0099]
In the above embodiment, the correction pattern in which the ink color is cyan, the correction pattern in which the ink color is magenta, the correction pattern in which the ink color is yellow, and the ink pattern The correction pattern in which the color is light black, the correction pattern in which the ink color is light cyan, and the correction pattern in which the ink color is light magenta belong to the same group. Although the group is different from the group to which the correction pattern whose color is black belongs, the present invention is not limited to this, and other groupings may be adopted.
[0100]
As described above, when reading the density of the correction pattern, the light emitted from the light emitting portion of the reflective optical sensor, that is, the incident light is reflected by the correction pattern on the printing paper, and the reflected light is reflected by the reflective optical sensor. Is received by the light receiving unit and converted into an electrical signal. In such light reception, it is necessary to secure a sufficient output level difference between adjacent sub-patterns.
[0101]
On the other hand, the obtained output level difference differs depending on the color of the correction pattern. That is, the light color correction pattern has a smaller output level difference than the dark color correction pattern.
Therefore, by making the dot resolution finer for lighter correction patterns, it is possible to ensure a sufficient output level difference, and as a result, it is possible to perform highly accurate misalignment correction.
[0102]
The above grouping is determined from such a viewpoint, and the above embodiment is more preferable in that a highly accurate deviation correction is possible.
Note that the grouping is not necessarily based on the assumption that there are seven colors of ink as described above.
[0103]
Moreover, in the said embodiment, although two embodiment was mentioned as an example about the procedure of the formation process of the pattern for a correction | amendment, you may combine the said 2 examples. For example, a light magenta correction pattern and a light cyan correction pattern are formed in parallel, and when both correction patterns are formed, two overstrikes are performed, and dots of both correction patterns are formed. The resolution may be 720 dpi.
[0104]
In the above embodiment, the correction pattern is formed by ejecting liquid from some of the nozzles constituting the nozzle row. However, the present invention is not limited to this. For example, in a printer having an ejection head configured with a plurality of nozzle rows arranged in the sub-scanning direction, when performing a plurality of correction pattern forming operations in parallel, all the nozzles of the plurality of nozzle rows Ink may be ejected from the head.
[0105]
=== Configuration of Printing System etc. ===
Next, an embodiment of a printing system as a liquid ejection system, which is an example of an embodiment according to the present invention, will be described with reference to the drawings.
[0106]
FIG. 15 is an explanatory diagram showing an external configuration of the printing system. The printing system 1000 includes a computer 1102, a display device 1104, a printer 1106, an input device 1108, and a reading device 1110. In this embodiment, the computer 1102 is housed in a mini-tower type housing, but is not limited thereto. The display device 1104 is generally a CRT (Cathode Ray Tube), a plasma display, a liquid crystal display device, or the like, but is not limited thereto. As the printer 1106, the printer described above is used. In this embodiment, the input device 1108 is a keyboard 1108A and a mouse 1108B, but is not limited thereto. In this embodiment, the reading device 1110 uses a flexible disk drive device 1110A and a CD-ROM drive device 1110B. However, the reading device 1110 is not limited to this. Disk) etc. may be used.
[0107]
FIG. 16 is a block diagram showing the configuration of the printing system shown in FIG. An internal memory 1202 such as a RAM and an external memory such as a hard disk drive unit 1204 are further provided in a housing in which the computer 1102 is housed.
[0108]
In the above description, the printer 1106 is connected to the computer 1102, the display device 1104, the input device 1108, and the reading device 1110 to configure the printing system. However, the present invention is not limited to this. . For example, the printing system may include a computer 1102 and a printer 1106, and the printing system may not include any of the display device 1104, the input device 1108, and the reading device 1110.
[0109]
For example, the printer 1106 may have a part of the functions or mechanisms of the computer 1102, the display device 1104, the input device 1108, and the reading device 1110. As an example, the printer 1106 includes an image processing unit that performs image processing, a display unit that performs various displays, a recording medium attachment / detachment unit for attaching / detaching a recording medium that records image data captured by a digital camera or the like. It is good also as a structure to have.
[0110]
The printing system realized in this way is a system superior to the conventional system as a whole system.
[0111]
【The invention's effect】
According to the present invention, it is possible to realize a liquid ejecting apparatus and a liquid ejecting system that efficiently perform a correction pattern forming process for correcting misalignment of dot formation positions.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a printing system including an inkjet printer 22;
FIG. 2 is a block diagram illustrating a configuration of a printer 22 as an example of a liquid ejecting apparatus centering on a control circuit 40;
FIG. 3 is a schematic diagram for explaining an example of a reflective optical sensor 29;
FIG. 4 is an explanatory diagram showing a schematic configuration inside the ejection head 60;
FIG. 5 is an explanatory diagram showing in detail the structure of a piezo element PE and a nozzle Nz.
6 is an explanatory diagram showing the arrangement of nozzles Nz in the ejection head 60. FIG.
7 is a block diagram showing a configuration of a drive signal generator provided in the head drive circuit 52. FIG.
FIG. 8 is a diagram for explaining an outline of a correction pattern for correcting a shift in dot formation position in the main scanning direction.
FIG. 9 is a flowchart for explaining a procedure according to the first embodiment of a correction pattern forming process;
FIGS. 10A to 10C are schematic diagrams according to the first embodiment showing the positional relationship between the nozzle array and the printing paper P when performing the correction pattern forming process. FIGS.
FIG. 11 is a diagram according to the first embodiment showing a paper feed amount and a use nozzle when performing a correction pattern forming process.
FIG. 12 is a flowchart for explaining a procedure according to a second embodiment of a correction pattern forming process;
FIGS. 13A to 13C are schematic diagrams according to the second embodiment showing the positional relationship between the nozzle array and the printing paper P when the correction pattern forming process is performed. FIGS.
FIG. 14 is a diagram according to a second embodiment showing a paper feed amount and a use nozzle when performing a correction pattern forming process.
FIG. 15 is an explanatory diagram showing an external configuration of a printing system.
16 is a block diagram showing a configuration of the printing system shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 22 Inkjet printer 23 Paper feed motor 24 Carriage motor 26 Platen 29 Reflection type optical sensor 29a Light emission part 29b Light reception part 31 Carriage 32 Operation panel 34 Slide shaft 36 Drive belt 38 Pulley 39 Position detection sensor 40 Control circuit 41 CPU 43 PROM
44 RAM 45 Character generator (CG)
50 I / F dedicated circuit 52 Head drive circuit 53 Reflective optical sensor control circuit 54 Motor drive circuit 56 Connector 60 Discharge head 60a-60g Discharge head for each color 67 Introducing pipe 68 Ink passage 71 Cartridge 71a For black (K) ink Cartridge 71b Cartridge for light black (LK) ink 71c Cartridge for cyan (C) ink 71d Cartridge for light cyan (LC) ink 71e Cartridge for magenta (M) ink 71f Light magenta (LM) ink Cartridge 71g Yellow color (Y) ink cartridge 90 Computer 204 Mask circuit 206 Original drive signal generation unit 230 Drive signal correction unit 1000 Printing system 1102 Computer 1104 Display device 1106 Printer 1108 Input device 1108A Keyboard 1108B Mouse 1110 Reading device 1110A Flexible disk drive device 1110B CD-ROM drive device 1202 Internal memory 1204 Hard disk drive unit Ip Ink droplet Nz Nozzle P Printing paper PE Piezo element PS Printing signal

Claims (14)

A sub-scanning movement mechanism for moving the medium in the sub-scanning direction;
An ejection head having nozzle rows in which nozzles for ejecting liquid to form dots on the medium are arranged in a row along the sub-scanning direction;
A main scanning movement mechanism for moving the ejection head in a main scanning direction intersecting the sub-scanning direction;
Drive control means for controlling the driving of the ejection head to form a plurality of correction patterns on the medium for correcting the dot formation position in the main scanning direction by ejection from the nozzle row;
With
The ejection head includes a first nozzle row that ejects a first color liquid, a second nozzle row that ejects a second color liquid, and a third nozzle that ejects a third color liquid. and columns are arranged in the main scanning direction,
The drive control means includes
When the ejection head is moving, the difference between the ejection timing from the first nozzle row and the ejection timing from the third nozzle row is determined by dividing the ideal inter-dot distance into N equal parts (N is (Natural number) is shifted by a distance divided by a distance, and a plurality of sub-patterns shifted by the distance are arranged in the main scanning direction to form a first correction pattern composed of the plurality of sub-patterns. As well as
When the ejection head is moved, the difference between the ejection timing from the second nozzle row and the ejection timing from the third nozzle row is determined by dividing the ideal inter-dot distance into N equal parts (N is A plurality of sub-patterns that are shifted by the respective distances are formed side by side in the main scanning direction, and a second correction pattern composed of the plurality of sub-patterns is converted into the first correction pattern. Control for forming the correction patterns side by side in the sub-scanning direction,
The sub-scanning movement mechanism is a liquid ejection unit that does not move the medium in the sub-scanning direction when the second correction pattern is formed side by side in the sub-scanning direction with respect to the first correction pattern. apparatus. A sub-scanning movement mechanism for moving the medium in the sub-scanning direction;
An ejection head having nozzle rows in which nozzles for ejecting liquid to form dots on the medium are arranged in a row along the sub-scanning direction;
A main scanning movement mechanism for moving the ejection head in a main scanning direction intersecting the sub-scanning direction;
Drive control means for controlling the driving of the ejection head to form a plurality of correction patterns on the medium for correcting the dot formation position in the main scanning direction by ejection from the nozzle row;
With
The discharge head includes a first nozzle array for ejecting a liquid of a first color, a second nozzle array for ejecting a liquid of a second color is arranged in the main scanning direction,
The drive control means includes
When the ejection head is reciprocating, the timing of ejection from the first nozzle row in the forward path of movement of the ejection head and the ejection timing from the first nozzle row in the backward path of movement of the ejection head The difference from the timing is shifted by a distance obtained by dividing the ideal inter-dot distance into N equal parts (N is a natural number), and a plurality of sub-patterns each shifted by the distance are formed side by side in the main scanning direction. While performing control to form the first correction pattern configured by the sub-pattern,
Timing of ejection from the second nozzle row in the forward path of movement of the ejection head and timing of ejection from the second nozzle row in the return path of movement of the ejection head during the reciprocation of the ejection head Are shifted by the distance obtained by dividing the ideal inter-dot distance into N equal parts (N is a natural number), and a plurality of sub-patterns each shifted by the distance are formed side by side in the main scanning direction. Executing a control to form a second correction pattern composed of sub-patterns in the sub-scanning direction with respect to the first correction pattern;
The sub-scanning movement mechanism is a liquid ejection unit that does not move the medium in the sub-scanning direction when the second correction pattern is formed side by side in the sub-scanning direction with respect to the first correction pattern. apparatus. The first correction pattern and the second correction pattern are divided into the same group among a plurality of groups based on the dot resolution in the nozzle row direction,
The sub-scanning movement mechanism forms the correction pattern of a different group among the plurality of groups than the amount of movement of the medium while the correction pattern of the same group among the plurality of groups is formed. The liquid ejecting apparatus according to claim 2, wherein an amount of moving the medium while the medium is moved is increased. In the first correction pattern and the second correction pattern , the number of overstrikes of the same color dot is set to be larger in the lighter correction pattern, and a plurality of overstrikes are determined based on the number of overstrikes. Divided into the same group ,
4. The liquid ejection apparatus according to claim 1, wherein the sub-scanning movement mechanism does not move the medium while the correction pattern of the same group among the plurality of groups is formed. 5. A density reading means for reading the density of the sub-pattern,
When the density of the sub-pattern in the first group among the plurality of groups is lower than the density of the sub-pattern in the second group among the plurality of groups, the overstrike of the first group The liquid ejecting apparatus according to claim 4, wherein the number of times is greater than the number of times of overstrike in the second group.   The liquid ejection apparatus according to claim 5, wherein the correction pattern using yellow is included in the first group, and the correction pattern using black is included in the second group.   The liquid ejection apparatus according to claim 5, wherein the first group includes the correction pattern using light magenta, and the second group includes the correction pattern using black.   The liquid ejection apparatus according to claim 1, wherein the dot resolution of the correction pattern is 180 dpi or 360 dpi.   The liquid ejection apparatus according to claim 1, wherein the dot resolution of the correction pattern is 720 dpi.   The liquid discharge apparatus according to claim 1, wherein the discharge head discharges ink by a piezo element. A method of forming a correction pattern by a liquid ejection device,
The liquid ejecting apparatus includes: a sub-scanning movement mechanism that moves the medium in the sub-scanning direction; and a nozzle in which nozzles for ejecting liquid to form dots on the medium are arranged in a line along the sub-scanning direction An ejection head having a row; a main scanning movement mechanism that moves the ejection head in a main scanning direction intersecting the sub-scanning direction; and the main scanning by controlling the ejection head to eject from the nozzle row Drive control means for forming a plurality of correction patterns for correcting the dot formation position in the direction on the medium,
The ejection head includes a first nozzle row that ejects a first color liquid, a second nozzle row that ejects a second color liquid, and a third nozzle that ejects a third color liquid. and columns are arranged in the main scanning direction,
The drive control means is
When the ejection head is moving, the difference between the ejection timing from the first nozzle row and the ejection timing from the third nozzle row is determined by dividing the ideal inter-dot distance into N equal parts (N is A process of forming a first correction pattern composed of the plurality of sub-patterns by shifting each of the sub-patterns shifted by the distance divided by (natural number) and arranging a plurality of sub-patterns shifted by the distance in the main scanning direction. As well as
When the ejection head moves, the difference between the ejection timing from the second nozzle row and the ejection timing from the third nozzle row is determined by dividing the ideal inter-dot distance into the N equal parts (N is A plurality of sub-patterns that are shifted by the respective distances are formed side by side in the main scanning direction, and a second correction pattern composed of the plurality of sub-patterns is converted into the first correction pattern. A process of forming the correction patterns side by side in the sub-scanning direction,
The sub-scanning movement mechanism does not move the medium in the sub-scanning direction when the second correction pattern is formed side by side in the sub-scanning direction with respect to the first correction pattern. A characteristic correction pattern forming method. A method of forming a correction pattern by a liquid ejection device,
The liquid ejecting apparatus includes: a sub-scanning movement mechanism that moves the medium in the sub-scanning direction; and a nozzle in which nozzles for ejecting liquid to form dots on the medium are arranged in a line along the sub-scanning direction An ejection head having a row; a main scanning movement mechanism that moves the ejection head in a main scanning direction intersecting the sub-scanning direction; and the main scanning by controlling the ejection head to eject from the nozzle row Drive control means for forming a plurality of correction patterns for correcting the dot formation position in the direction on the medium,
The discharge head includes a first nozzle array for ejecting a liquid of a first color, a second nozzle array for ejecting a liquid of a second color is arranged in the main scanning direction,
The correction pattern includes a first correction pattern and a second correction pattern in the sub-scanning direction,
The drive control means is
When the ejection head is reciprocating, the timing of ejection from the first nozzle row in the forward path of movement of the ejection head and the ejection timing from the first nozzle row in the backward path of movement of the ejection head The difference from the timing is shifted by a distance obtained by dividing the ideal inter-dot distance into N equal parts (N is a natural number), and a plurality of sub-patterns each shifted by the distance are formed side by side in the main scanning direction. While performing the process which forms the 1st correction pattern comprised by a sub pattern,
Timing of ejection from the second nozzle row in the forward path of movement of the ejection head and timing of ejection from the second nozzle row in the return path of movement of the ejection head during the reciprocation of the ejection head Are shifted by the distance obtained by dividing the ideal inter-dot distance into N equal parts (N is a natural number), and a plurality of sub-patterns each shifted by the distance are formed side by side in the main scanning direction. Executing a process of forming a second correction pattern composed of sub-patterns in the sub-scanning direction with respect to the first correction pattern;
The sub-scanning movement mechanism does not move the medium in the sub-scanning direction when the second correction pattern is formed side by side in the sub-scanning direction with respect to the first correction pattern. A characteristic correction pattern forming method. A liquid ejection system having a computer and a liquid ejection device connectable to the computer,
The liquid ejection device includes:
A sub-scanning movement mechanism for moving the medium in the sub-scanning direction;
An ejection head having nozzle rows in which nozzles for ejecting liquid to form dots on the medium are arranged in a row along the sub-scanning direction;
A main scanning movement mechanism for moving the ejection head in a main scanning direction intersecting the sub-scanning direction;
Drive control means for controlling the driving of the ejection head to form a plurality of correction patterns on the medium for correcting the dot formation position in the main scanning direction by ejection from the nozzle row;
With
The ejection head includes a first nozzle row that ejects a first color liquid, a second nozzle row that ejects a second color liquid, and a third nozzle that ejects a third color liquid. and columns are arranged in the main scanning direction,
The drive control means is configured to detect the timing of ejection from the first nozzle row and the ejection timing from the third nozzle row when the ejection head is moving based on a control signal supplied from the computer. The difference from the timing is shifted by the distance obtained by dividing the ideal inter-dot distance into N equal parts (N is a natural number), and a plurality of sub-patterns shifted by the distance are formed side by side in the main scanning direction. While performing control to form the first correction pattern configured by the sub-pattern,
When the ejection head is moved, the difference between the ejection timing from the second nozzle row and the ejection timing from the third nozzle row is determined by dividing the ideal inter-dot distance into N equal parts (N is A plurality of sub-patterns that are shifted by the respective distances are formed side by side in the main scanning direction, and a second correction pattern composed of the plurality of sub-patterns is converted into the first correction pattern. Control for forming the correction patterns side by side in the sub-scanning direction,
The sub-scanning movement mechanism is a liquid ejection device that does not move the medium in the sub-scanning direction when the second correction pattern is formed side by side in the sub-scanning direction with respect to the first correction pattern. A liquid ejection system comprising: A liquid ejection system having a computer and a liquid ejection device connectable to the computer,
The liquid ejection device includes:
A sub-scanning movement mechanism for moving the medium in the sub-scanning direction;
An ejection head having nozzle rows in which nozzles for ejecting liquid to form dots on the medium are arranged in a row along the sub-scanning direction;
A main scanning movement mechanism for moving the ejection head in a main scanning direction intersecting the sub-scanning direction;
Drive control means for controlling the driving of the ejection head to form a plurality of correction patterns on the medium for correcting the dot formation position in the main scanning direction by ejection from the nozzle row;
With
The discharge head includes a first nozzle array for ejecting a liquid of a first color, a second nozzle array for ejecting a liquid of a second color is arranged in the main scanning direction,
The drive control means, based on a control signal supplied from the computer, when the discharge head is reciprocating, the timing of discharge from the first nozzle row in the forward path of movement of the discharge head, and the The difference between the timing of ejection from the first nozzle row in the return path of the ejection head movement is shifted by a distance obtained by dividing the ideal inter-dot distance into N equal parts (N is a natural number), and a plurality of distances shifted by the distance. Are arranged side by side in the main scanning direction to perform control to form a first correction pattern composed of the plurality of sub patterns,
Timing of ejection from the second nozzle row in the forward path of movement of the ejection head and timing of ejection from the second nozzle row in the return path of movement of the ejection head during the reciprocation of the ejection head Are shifted by the distance obtained by dividing the ideal inter-dot distance into N equal parts (N is a natural number), and a plurality of sub-patterns each shifted by the distance are formed side by side in the main scanning direction. Executing a control to form a second correction pattern composed of sub-patterns in the sub-scanning direction with respect to the first correction pattern;
The sub-scanning movement mechanism is a liquid ejection device that does not move the medium in the sub-scanning direction when the second correction pattern is formed side by side in the sub-scanning direction with respect to the first correction pattern. A liquid ejection system comprising:

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