JP4529376B2 - Liquid ejection device, correction pattern, 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, a correction pattern formation 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 such misalignment of dot formation positions, printing paper is obtained by ejecting ink from nozzles provided in the ejection head with a correction pattern for correcting the misalignment having a plurality of sub-patterns having different densities. In this method, the density of each sub-pattern is read by the density reading means, and the deviation is corrected based on the read density information (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-329381
[0006]
[Problems to be solved by the invention]
However, because of the restriction of the space in the downsized printer, etc., the ink flow path supplied from the ink cartridge is only provided near the center of each nozzle row. It is difficult to supply the same to all nozzles provided in the nozzle row.
[0007]
Attention is now directed to FIG. FIG. 9 is a diagram showing dot formation positions when ink is ejected from all the nozzles provided in the nozzle row all at once to form dots on the printing paper. The solid line shown in FIG. 9 indicates the set of dots, and the dotted line indicates the position of the dots formed by ejecting ink from the central nozzle in the nozzle row. When forming dots on the printing paper, the ejection head provided with the nozzles moves in the direction of the arrow shown in FIG. In FIG. 9, four types of the dot formation positions are shown. This indicates that the dot formation positions may be different depending on the nozzle array that ejects ink due to manufacturing errors of the ejection head. Yes.
[0008]
As is apparent from FIG. 9, due to the difficulty of supplying the ink supplied from the center to all the nozzles provided in the nozzle row in the same manner, a slight deviation of the ink discharge speed may occur for each nozzle. . For example, looking at the dot formation position shown second from the right in FIG. 9, the ejection speed of the ink ejected from the central nozzle is smaller than the ejection speed of the ink ejected from the end nozzle. Recognize.
[0009]
When the correction pattern is formed by ejecting ink from all the nozzles in the nozzle row where the deviation of the dot formation position occurs for each nozzle as described above, the density in one sub-pattern is in the nozzle row direction. There is a risk that it will vary greatly. Then, when the density of the plurality of sub patterns is read by the density reading unit and the deviation is corrected based on the read density information, it is obtained depending on which part of the sub pattern the density in the nozzle row direction is read. There is a possibility that the correction value for the deviation correction is different. In such a situation, there may be an obstacle to ensuring that the correct misalignment correction is performed.
[0010]
The present invention has been made in view of the above problems, and the object of the present invention is to provide a liquid ejection apparatus that forms a correction pattern capable of appropriately correcting a shift in dot formation position, and an appropriate shift in dot formation position. A correction pattern that can be corrected in a correct manner, a correction pattern forming method for the correction pattern, and a liquid discharge system including the liquid discharge apparatus.
[0011]
[Means for Solving the Problems]
The main present invention has a nozzle row in which a plurality of nozzles are arranged in a row in the sub-scanning direction, and ejects liquid supplied from a flow path provided in the center of the nozzle row to form dots on the medium. An ejection head for forming, a sub-scanning movement mechanism for moving the medium in the sub-scanning direction, a main scanning movement mechanism for moving the ejection head in a main scanning direction intersecting the sub-scanning direction, and the ejection head. Drive Said Control to discharge liquid from nozzle In this case, 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 is changed for each sub-pattern, so A correction pattern configured by arranging patterns in the main scanning direction is formed on the medium. Drive control means, and based on the difference in the density of the sub-pattern, The dot formation position in the main scanning direction formed by discharging liquid from the nozzle row in the forward path, and the dot formation position in the main scanning direction formed by discharging liquid from the nozzle row in the backward path Correcting the misalignment In the liquid discharge apparatus, the nozzle row is divided into a plurality of sub nozzle rows, and the drive control unit drives the discharge head to discharge liquid from the nozzles included in the sub nozzle rows. The correction patterns corresponding to the sub-patterns are formed side by side in the sub-scanning direction, further comprising density reading means for reading the density of the sub-pattern, and the density reading means uses a sub-pattern for each correction pattern. A liquid that reads a density, acquires a correction value for correcting the shift for each of the correction patterns based on the read density information, and corrects the shift based on an average value of the correction values. It is a discharge device.
Other features of the present invention will become apparent from this specification and the accompanying drawings.
[0012]
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 correction pattern having a plurality of sub-patterns having different densities, each having a discharge head including a nozzle row in which nozzles for forming dots on a medium by discharging liquid are arranged in a row, 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 density of the sub-pattern is discharged from the discharge head onto the medium. In the liquid ejection apparatus to be formed, the liquid ejection apparatus forms the correction pattern by ejecting the liquid from a part of the nozzles constituting the nozzle row.
By forming the correction pattern by discharging the liquid from some of the nozzles constituting the nozzle row, a correction pattern capable of appropriately correcting a shift in dot formation position is formed. Is possible.
[0013]
Further, the correction pattern may be formed by ejecting the liquid from the nozzle located in the center of the nozzle row among the nozzles constituting the nozzle row.
In this way, it is possible to form a correction pattern that can correct the deviation of the dot formation position more appropriately.
[0014]
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.
[0015]
The nozzle row includes a plurality of sub-nozzle rows, and a plurality of the correction patterns corresponding to the sub-nozzle rows by ejecting the liquid from some of the nozzles constituting the sub-nozzle row. It is good also as forming.
In this way, it is possible to form a correction pattern that can correct the deviation of the dot formation position more appropriately.
[0016]
Further, the image reading apparatus includes a density reading unit for reading the density of the sub-pattern, reads the density of the sub-pattern by the density reading unit, and determines each of the plurality of correction patterns based on the read density information. A correction value for correcting the deviation may be acquired, and the deviation may be corrected based on an average value of the correction values.
In this way, more appropriate misalignment correction can be performed based on the average value.
[0017]
The ejection head includes a plurality of the nozzle rows, and the correction pattern has dot formation positions in the intersecting direction of dots formed by ejecting liquid from the first nozzle row among the plurality of nozzle rows. And a correction pattern for correcting a deviation between dots formed by ejecting liquid from another second nozzle row different from the first nozzle row and the dot formation position in the intersecting direction. Also good.
In this way, it is possible to form a Uni-D adjustment pattern that can appropriately correct the deviation of the dot formation position.
[0018]
The correction pattern includes dots formed by discharging liquid from the first nozzle row, and dots formed by discharging liquid from the second nozzle row, and the first pattern The plurality of sub-patterns formed by changing the difference between the timing of ejecting liquid from one nozzle row and the timing of ejecting liquid from the second nozzle row for each sub-pattern may be provided. .
In this way, it is possible to more appropriately obtain a correction value for correcting the deviation based on the read density information.
[0019]
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 may be a correction pattern for correcting deviation of dots from the dot formation position in the intersecting direction.
In this way, it is possible to form a Bi-D adjustment pattern capable of appropriately correcting the deviation of the dot formation position.
[0020]
The correction pattern includes dots formed by ejecting liquid from the nozzle row in the forward path of main scanning, and dots formed by ejecting liquid from the nozzle row in the return path, and The plurality of sub-patterns formed by changing, for each sub-pattern, the difference between the timing at which liquid is ejected from the nozzle row in the forward pass of main scanning and the timing at which liquid is ejected from the nozzle row in the return pass. It is good to be.
In this way, it is possible to more appropriately obtain a correction value for correcting the deviation based on the read density information.
[0021]
The sub-pattern may be configured by arranging dots in the direction of the nozzle row and the intersecting direction.
In this way, it is possible to form a correction pattern with good density readability.
[0022]
The correction pattern includes a plurality of sub-patterns having different densities, each having a discharge head including a nozzle array in which nozzles for forming dots on the medium by discharging liquid are arranged in a line. Then, a correction pattern for correcting the deviation of the dot formation position in the intersecting direction intersecting the direction of the nozzle row based on the difference in density of the sub-pattern is discharged from the discharge head to discharge the liquid. In the liquid ejection device formed on the medium, the liquid is ejected from some of the nozzles constituting the nozzle row to form the correction pattern, and among the nozzles constituting the nozzle row, There is a density reading means for discharging the liquid from the nozzle located in the center of the nozzle row to form the correction pattern and reading the density of the sub-pattern. The density reading unit reads the density of the sub-pattern, corrects the deviation based on the read density information, the ejection head includes a plurality of nozzle rows, and the correction pattern includes the plurality of nozzles. It is formed by ejecting liquid from the dot forming position in the intersecting direction of dots formed by ejecting liquid from the first nozzle row in the row and from another second nozzle row different from the first nozzle row. A correction pattern for correcting a deviation of dots in the intersecting direction with the dot formation position, wherein the correction pattern includes dots formed by ejecting liquid from the first nozzle row, and the second pattern. Dots formed by discharging liquid from the nozzle row, and a timing at which liquid is discharged from the first nozzle row and a timing at which liquid is discharged from the second nozzle row A plurality of sub-patterns formed by changing the sub-pattern for each sub-pattern, and the sub-pattern is configured by arranging dots in the nozzle row direction and the intersecting direction. It is also possible to realize a liquid ejection device.
In this way, the object of the present invention can be achieved more effectively because most of the effects described above can be achieved.
[0023]
Further, the liquid is ejected from the ejection head by the liquid ejection device having a nozzle row in which nozzles for ejecting liquid to form dots on the medium are arranged in a row, and the medium A correction pattern having a plurality of sub-patterns with different densities formed in the sub-pattern, and the deviation of dot formation positions in the intersecting direction intersecting the nozzle row direction based on the difference in the densities of the sub-patterns. In the correction pattern for correction, it is also possible to realize a correction pattern that is formed by discharging the liquid from some of the nozzles constituting the nozzle row.
[0024]
With the correction pattern formed by discharging the liquid from some of the nozzles constituting the nozzle row, it is possible to properly correct the deviation of the dot formation position.
[0025]
Next, correction with a plurality of sub-patterns having different densities is performed by a liquid ejection apparatus having an ejection head having a nozzle row in which nozzles for ejecting liquid to form dots on a medium are arranged in a row. A correction pattern for correcting a deviation in dot formation position in the intersecting direction intersecting the direction of the nozzle row based on the difference in density of the sub-pattern, and the liquid from the discharge head. In the correction pattern forming method for discharging and forming on the medium, the correction pattern is formed by discharging the liquid from some of the nozzles constituting the nozzle row to form the correction pattern. Pattern forming method.
By such a correction pattern forming method, it is possible to form a correction pattern capable of appropriately correcting the shift of the dot formation position.
[0026]
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 having a plurality of sub-patterns having different densities, and forming dots in a crossing direction that intersects the nozzle row direction based on the density differences of the sub-patterns A liquid ejection apparatus for ejecting the liquid from the ejection head to form a correction pattern for correcting a positional shift on the medium, and a part of the nozzles constituting the nozzle row It is also possible to realize a liquid discharge system comprising a liquid discharge device that forms the correction pattern by discharging the liquid.
The liquid ejection system thus realized is a system that is superior to conventional systems as a whole system.
[0027]
=== 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.
[0028]
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.
[0029]
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.
[0030]
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.
[0031]
As shown in FIG. 2, the control circuit 40 is configured as an arithmetic and logic circuit including a CPU 41, a programmable ROM (PROM) 43, a RAM 44, and a character generator (CG) 45 that stores 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 reflective optical sensor are provided. The I / F dedicated circuit 50 includes 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.
[0032]
=== 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.
The reflective optical sensor 29 is attached to the carriage 31, and includes a light emitting unit 29a formed of, for example, a light emitting diode and a light receiving unit 29b formed of, 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.
[0033]
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.
[0034]
=== 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.
[0035]
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.
[0036]
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.
[0037]
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.
[0038]
Each color ejection head 60a, 60b, 60c, 60d, 60e, 60f, 60g provided at the lower part of the carriage 31 is provided with a piezo element PE that is one of electrostrictive elements and excellent in responsiveness for each nozzle Nz. Has been placed. 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 a 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 extends 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.
[0039]
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.
[0040]
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, the position of the reflective optical sensor 29 in the sub-scanning direction is as shown in the figure. 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.
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.
[0041]
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.
[0042]
=== 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 signal generator provided in the head drive circuit 52 (FIG. 2) shown in FIG. 7 is provided for each nozzle row.
[0043]
=== 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.
[0044]
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 forming 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.
[0045]
<<< 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.
[0046]
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.
[0047]
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.
[0048]
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.
[0049]
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.
[0050]
<<< 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.
[0051]
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.
[0052]
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.
[0053]
For example, regarding the subpattern P1 and the subpattern P2, the difference between the forward discharge timing and the backward discharge timing in the subpattern P1 is ΔP1, and the forward discharge timing and the backward discharge timing in the subpattern P2 are When the deviation is ΔP2, | ΔP1−ΔP2 | = 1/1440 inch.
[0054]
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.
[0055]
<<< Regarding Method for Correcting Misalignment of Dot Forming 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-light with the lowest density is based on the electrical signal as density information. A pattern 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).
[0056]
As will be described later, when a plurality of correction patterns are formed for each sub-nozzle row, the density of the sub-pattern is read for each correction pattern, and a plurality of corrections are performed based on the read density information. A correction value for deviation correction is acquired for each of the patterns for use. When printing is performed later, an average value of these correction values is input to the drive signal correction unit 230 described above, and the shift is corrected.
[0057]
=== Regarding the nozzle used for forming the correction pattern ===
Next, the nozzles used when forming the above-described correction pattern will be described with reference to FIGS. FIG. 10 is an explanatory diagram for explaining the first embodiment. FIG. 11 is an explanatory diagram for explaining the second embodiment.
[0058]
In the present embodiment, a correction pattern is formed on the printing paper P by ejecting ink from some of the nozzles constituting the nozzle row described above.
By doing so, it is possible to form a correction pattern capable of appropriately correcting the deviation of the dot formation position.
[0059]
That is, as described in the section of the problem to be solved by the invention, the ink supplied from the center is the same for every nozzle due to the difficulty of supplying the ink to all the nozzles provided in the nozzle row. A slight deviation in the discharge speed can occur. In the case where the correction pattern is formed by ejecting ink from all nozzles in the nozzle row in which the deviation of the ink ejection speed occurs for each nozzle, the density in one sub-pattern is in the nozzle row direction. There is a risk that it will be very different. When the density of a plurality of sub patterns is read by the reflective optical sensor 29 serving as a density reading means, and the deviation is corrected based on the read density information, the density of which part in the nozzle row direction in the sub pattern is determined. There is a possibility that the correction value for deviation correction obtained differs depending on whether the reading is performed.
[0060]
Therefore, as described above, a correction pattern is formed on the printing paper P by ejecting ink from some of the nozzles constituting the nozzle row.
By doing so, it is possible to avoid the above-mentioned disadvantage that the density in one sub-pattern is greatly different in the nozzle row direction. Then, when the density of a plurality of sub patterns is read by the reflective optical sensor 29 and the deviation is corrected based on the read density information, the density of any portion in the nozzle row direction in the sub pattern can be read, An appropriate correction value can be obtained. Therefore, it is possible to ensure that proper deviation correction is performed.
Next, as an example of forming a correction pattern on the printing paper P by ejecting ink from some of the nozzles constituting the nozzle row, two embodiments will be described.
[0061]
<<<< first embodiment >>>>
First, a first embodiment will be described with reference to FIG. As shown in FIG. 10, in the present embodiment, a correction pattern is formed by ejecting ink from a nozzle located in the center of the nozzle row among the nozzles constituting the nozzle row. More specifically, among the nozzles # 1 to # 180 constituting the nozzle row, ink is ejected from the nozzles # 69 to # 112 to form a correction pattern.
[0062]
In FIG. 10, only one nozzle row is shown for easy understanding of the drawing. However, as described above, in the case of Uni-D adjustment, two nozzles are used for forming a correction pattern. Use columns. Further, only one correction pattern is shown for easy understanding of the description. However, in order to ensure Uni-D adjustment and Bi-D adjustment, a plurality of correction patterns are provided for each nozzle row. Need to form.
[0063]
Further, by forming ink for the correction pattern by ejecting ink from the nozzles # 69 to # 112, the sub-pattern of the correction pattern has dots arranged in the main scanning direction and the sub-scanning direction as shown in FIG. Will be configured.
[0064]
In the present embodiment, when forming the correction pattern, the dot resolution in the sub-scanning direction 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.
[0065]
Thus, by forming ink for correction from the nozzles located in the center of the nozzle row among the nozzles constituting the nozzle row, the correction pattern is formed by discharging ink from some of the nozzles described above. In addition to the merits of forming a pattern, the following merits occur.
[0066]
The merits will be described again with reference to FIG. As described above, one flow path for the ink supplied from the ink cartridge is provided near the center of each nozzle row due to restrictions due to the space in the downsized printer. As a result, as shown in FIG. 9, the ink ejected from the nozzles located at the center of the nozzle row is more stably applied to the printing paper than the ink ejected from the nozzles located at the end of the nozzle row. Land. That is, when the four dot formation positions shown in FIG. 9 are compared, the ink has landed at substantially the same position in the central portion, but the ink landing positions vary considerably at the end portion.
Therefore, if a correction pattern is formed by ejecting ink from the nozzles located in the center of the nozzle row of the nozzle rows, and the sub-pattern density of the correction pattern is read by the reflective optical sensor 29, A more appropriate correction value can be obtained.
[0067]
<<< Second Embodiment >>>
Next, a second embodiment will be described with reference to FIG. As shown in FIG. 11, in this embodiment, the nozzle row is divided into a plurality of sub-nozzle rows, and ink is ejected from some of the nozzles constituting the sub-nozzle row to each sub-nozzle row. A plurality of corresponding correction patterns are formed. More specifically, the nozzle array composed of nozzles # 1 to # 180 is divided into a first sub nozzle array composed of nozzles # 1 to # 60 and a second sub nozzle array composed of nozzles # 61 to # 120. And the nozzles constituting the second sub nozzle row from nozzles # 9 to # 52 among the nozzles constituting the first sub nozzle row. Ink is ejected from nozzles # 69 to # 112 and nozzles # 129 to # 172 of the nozzles constituting the third sub nozzle row to form a plurality of correction patterns corresponding to the sub nozzle rows.
[0068]
In FIG. 11, only one nozzle row is shown for easy understanding of the drawing. As described above, in the case of Uni-D adjustment, two nozzles are used for forming a correction pattern. Use columns. For ease of explanation, FIG. 11 shows only one set of correction patterns including three correction patterns. However, in order to ensure Uni-D adjustment and Bi-D adjustment. Therefore, it is necessary to form a plurality of correction patterns for each nozzle row.
[0069]
Further, by forming ink correction patterns by ejecting ink from nozzles # 9 to # 52, nozzles # 69 to # 112, and nozzles # 129 to # 172, the sub-pattern of the correction pattern is represented in FIG. As described above, the dots are arranged in the main scanning direction and the sub-scanning direction.
[0070]
In the present embodiment, when forming the correction pattern, the dot resolution in the sub-scanning direction 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.
[0071]
As described above, the nozzle row is divided into a plurality of sub nozzle rows, and ink is ejected from some of the nozzles constituting the sub nozzle row to form a plurality of correction patterns corresponding to the sub nozzle rows. Thus, in addition to the advantages of forming the correction pattern by ejecting ink from some of the nozzles described above, the following advantages occur.
[0072]
That is, as described above, due to the difficulty of supplying the ink supplied from the center to all the nozzles provided in the nozzle row in the same manner, a slight deviation of the ink discharge speed may occur for each nozzle. Therefore, if a plurality of correction patterns are formed by ejecting ink from nozzles located at a plurality of locations in the nozzle row, such as the upper end portion, the central portion, and the lower end portion of the nozzle row, information necessary for correcting the misalignment. As a result, a larger amount can be obtained, and as a result, a more appropriate deviation correction can be performed.
[0073]
=== 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, cloth, metal thin plate, or the like may be used as the medium.
In the above-described embodiment, an ink jet printer has been described as an example of a liquid ejecting apparatus. However, 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.
[0074]
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.
[0075]
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. .
[0076]
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.
[0077]
In the above embodiment, the correction pattern is formed by ejecting ink from the nozzles located in the center of the nozzle row among the nozzles constituting the nozzle row. However, the present invention is not limited to this. is not.
However, for the reason described above, the above embodiment is more preferable in that it is possible to form a correction pattern that can correct the deviation of the dot formation position more appropriately.
[0078]
Further, in the above-described embodiment, a reflective optical sensor for reading the density of the sub-pattern is provided, the density of the sub-pattern is read by the reflective optical sensor, and the deviation is corrected based on the read density information. 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.
[0079]
Further, in the above embodiment, the nozzle row has a plurality of sub-nozzle rows, and the ink is ejected from some of the nozzles constituting the sub-nozzle row to correspond to each of the sub-nozzle rows. Although the plurality of correction patterns are formed, the present invention is not limited to this.
However, for the reason described above, the above embodiment is more preferable in that it is possible to form a correction pattern that can correct the deviation of the dot formation position more appropriately.
[0080]
Further, in the above-described embodiment, there is a reflective optical sensor for reading the density of the sub-pattern, the density of the sub-pattern is read by the reflective optical sensor, and a plurality of the above-mentioned density information is obtained based on the read density information. Although a correction value for correcting the shift is obtained for each correction pattern and the shift is corrected based on an average value of the correction values, the present invention is not limited to this. For example, the deviation may be corrected based on a median value of a plurality of correction values (for example, when there are three correction values, the second magnitude value).
However, the above-described embodiment is more desirable in that a more appropriate correction is possible if the deviation correction is performed based on the average value as described above.
[0081]
Further, in the above embodiment, the ejection head includes a plurality of nozzle rows, and the correction pattern is formed in the main scanning direction of dots formed by ejecting ink from the first nozzle row among the plurality of nozzle rows. A correction pattern for correcting a deviation between a dot formation position and a dot formation position in the main scanning direction of dots formed by ejecting ink from another second nozzle row different from the first nozzle row. However, the present invention is not limited to this.
However, by doing so, it is possible to form a Uni-D adjustment pattern capable of appropriately correcting the deviation of the dot formation position.
[0082]
In the above-described embodiment, the correction pattern includes dots formed by ejecting ink from the first nozzle row and dots formed by ejecting ink from the second nozzle row. And a plurality of sub-patterns 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. However, the present invention is not limited to this.
However, in this way, the correction value and the sub-pattern having a different density can be associated with each other, so that the correction value for correcting the deviation can be appropriately acquired based on the read density information. The above embodiment is more desirable.
[0083]
In the above-described embodiment, the correction pattern ejects ink from the nozzle array in the main scanning direction of dots formed by ejecting ink from the nozzle array in the main scanning forward path, and from the nozzle array in the backward path. The correction pattern for correcting the deviation of the dots formed in this way from the dot formation position in the main scanning direction is not limited to this.
However, by doing so, it is possible to form a Bi-D adjustment pattern capable of appropriately correcting the deviation of the dot formation position.
[0084]
In the above embodiment, the correction pattern includes dots formed by ejecting ink from the nozzle row in the forward path of main scanning, and dots formed by ejecting ink from the nozzle row in the return path; And a plurality of sub-patterns formed by changing, for each sub-pattern, a difference between a timing at which ink is ejected from the nozzle array in the forward path of main scanning and a timing at which ink is ejected from the nozzle array in the return path However, the present invention is not limited to this.
However, in this way, the correction value and the sub-pattern having a different density can be associated with each other, so that the correction value for correcting the deviation can be appropriately acquired based on the read density information. The above embodiment is more desirable.
[0085]
In the above embodiment, the sub-pattern is configured by arranging dots in the sub-scanning direction and the main-scanning direction. However, the present invention is not limited to this. For example, the sub-pattern may be configured such that dots are arranged only in the sub-scanning direction or only in the main scanning direction.
However, the above embodiment is more preferable in that a correction pattern with good density readability can be formed.
[0086]
=== 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.
FIG. 12 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.
[0087]
FIG. 13 is a block diagram illustrating a configuration of the printing system illustrated 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.
[0088]
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.
[0089]
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.
[0090]
The printing system realized in this way is a system superior to the conventional system as a whole system.
[0091]
【The invention's effect】
According to the present invention, a liquid ejection apparatus that forms a correction pattern capable of appropriately correcting a deviation in dot formation position, a correction pattern capable of appropriately correcting a deviation in dot formation position, and a correction pattern for the correction pattern A formation method and a liquid ejection system having the liquid ejection device can be realized.
[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 diagram showing dot formation positions when ink is ejected simultaneously from all nozzles provided in the nozzle row to form dots on the printing paper.
FIG. 10 is an explanatory diagram for explaining the first embodiment;
FIG. 11 is an explanatory diagram for explaining a second embodiment;
FIG. 12 is an explanatory diagram showing an external configuration of a printing system.
13 is a block diagram showing a configuration of the printing system shown in FIG. 12. FIG.
[Explanation of symbols]
22 Inkjet printer 23 Paper feed motor
24 Carriage motor 26 Platen
29 Reflective optical sensor 29a Light emitting part
29b Light receiver 31 Carriage
32 Operation panel 34 Sliding 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 Introduction pipe
68 Ink passage 71 Cartridge
71a Black (K) ink cartridge
71b Light black (LK) ink cartridge
71c Cyan cartridge for cyan (C) ink
71d Light Cyan (LC) ink cartridge
71e Magenta (M) ink cartridge
71f Light magenta (LM) ink cartridge
71g Yellow (Y) ink cartridge
90 computer 204 mask circuit
206 Original drive signal generator 230 Drive signal correction unit
1000 Printing System 1102 Computer
1104 Display device 1106 Printer
1108 Input device 1108A Keyboard
1108B Mouse 1110 Reader
1110A Flexible disk drive device
1110B CD-ROM drive device
1202 Internal memory
1204 Hard disk drive unit
Ip ink drops
Nz nozzle
P Printing paper
PE Piezo element
PS print signal

Claims (3)

Discharge for forming dots on a medium by having a nozzle array in which a plurality of nozzles are arranged in a row in the sub-scanning direction, and discharging liquid supplied from a flow path provided in the center of the nozzle array Head,
A sub-scanning movement mechanism for moving the medium in the sub-scanning direction;
A main scanning movement mechanism that moves the ejection head in a main scanning direction that intersects the sub-scanning direction;
Difference when performing control to eject liquid from the nozzle by driving the ejection head, the timing of ejecting the liquid through the nozzle row in the forward pass of the main scan, the timing of ejecting the liquid through the nozzle row in the backward Drive control means for forming, on the medium, a correction pattern configured by arranging a plurality of sub-patterns having different densities in the main scanning direction by changing the sub-pattern for each sub-pattern ,
Based on the difference in density of the sub-pattern, the liquid is ejected from the nozzle row in the main scanning direction formed by ejecting the liquid from the nozzle row in the forward path, and the nozzle row in the backward path. A liquid ejection apparatus that corrects a deviation from a dot formation position in the main scanning direction formed by :
The nozzle row is divided into a plurality of sub nozzle rows,
The drive control means drives the discharge head to discharge liquid from the nozzles included in the sub-nozzle rows, and forms the correction patterns corresponding to the sub-nozzle rows in the sub-scanning direction,
A density reading means for reading the density of the sub-pattern is further provided, the density reading means reads the density of the sub-pattern for each of the correction patterns, and each of the correction patterns is read based on the read density information. A liquid ejection apparatus that acquires a correction value for correcting the shift and corrects the shift based on an average value of the correction values. Discharge for forming dots on a medium by having a nozzle array in which a plurality of nozzles are arranged in a row in the sub-scanning direction, and discharging liquid supplied from a flow path provided in the center of the nozzle array Head,
A sub-scanning movement mechanism for moving the medium in the sub-scanning direction;
A main scanning movement mechanism that moves the ejection head in a main scanning direction that intersects the sub-scanning direction;
Difference when performing control to eject liquid from the nozzle by driving the ejection head, the timing of ejecting the liquid through the nozzle row in the forward pass of the main scan, the timing of ejecting the liquid through the nozzle row in the backward A liquid ejection apparatus comprising: a drive control unit configured to form, on the medium, a correction pattern configured by arranging a plurality of sub-patterns having different densities in the main scanning direction by changing the sub-pattern for each sub-pattern ,
Based on the difference in density of the sub-patterns, the liquid is ejected from the nozzle row in the main scanning direction formed by ejecting the liquid from the nozzle row in the forward path and the nozzle row in the backward path. In the correction pattern forming method for correcting the deviation from the dot formation position in the main scanning direction formed by :
The nozzle row is divided into a plurality of sub nozzle rows,
The drive control means drives the ejection head to eject liquid from the nozzles included in the sub-nozzle rows, and the correction patterns corresponding to the sub-nozzle rows are formed side by side in the sub-scanning direction,
The liquid ejection apparatus further includes a density reading unit for reading the density of the sub-pattern, and the density reading unit reads the density of the sub-pattern for each of the correction patterns, and based on the read density information, A correction pattern forming method comprising: obtaining a correction value for correcting the shift for each of the correction patterns, and correcting the shift based on an average value of the correction values. A computer, a display device connectable to the computer, and a liquid ejection device connectable to the computer, comprising a nozzle row in which a plurality of nozzles are arranged in a row along the sub-scanning direction, and the center of the nozzle row An ejection head for ejecting a liquid supplied from a flow path provided in the medium to form dots on the medium, a sub-scanning moving mechanism for moving the medium in the sub-scanning direction, and a main crossing the sub-scanning direction a main scanning mechanism for moving the ejection head in the scanning direction, when performing control to eject liquid from the nozzle by driving the ejection head, the timing of ejecting the liquid through the nozzle row in the forward pass of the main scan By changing the difference from the timing of ejecting the liquid from the nozzle row in the return path for each sub pattern, a plurality of sub patterns having different concentrations can be obtained. The correction pattern formed by arranging the serial main scanning direction and a drive control means for forming on said medium,
Based on the difference in density of the sub-pattern, the liquid is ejected from the nozzle row in the main scanning direction formed by ejecting the liquid from the nozzle row in the forward path, and the nozzle row in the backward path. A liquid ejection apparatus that corrects a deviation from a dot formation position in the main scanning direction formed by :
The nozzle row is divided into a plurality of sub nozzle rows,
The drive control means drives the discharge head to discharge liquid from the nozzles included in the sub-nozzle rows, and forms the correction patterns corresponding to the sub-nozzle rows in the sub-scanning direction,
A density reading means for reading the density of the sub-pattern is further provided. The density reading means reads the density of the sub-pattern for each of the correction patterns, and for each of the correction patterns based on the read density information. And a liquid ejection device that acquires a correction value for correcting the deviation and corrects the deviation based on an average value of the correction values.

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