JP7192544B2 - Recording position correction method, image recording device and recording position correction program - Google Patents

Description

TECHNICAL FIELD The present invention relates to a recording position correction method, an image recording apparatus, and a recording position correction program, and more particularly, correction for achieving connection between images recorded by each head module in the same line head and correspondence between different line heads. The present invention relates to a recording position correction method, an image recording apparatus, and a recording position correction program that are compatible with correction (color misregistration correction) that achieves matching of recording positions between images recorded by head modules.

A so-called "one-pass inkjet printer" is an image recording apparatus that records an image line by line (row), and is capable of recording at a higher speed than a "serial printer" that records an image dot by dot. For this reason, it has conventionally been suitably used as an image recording apparatus for business use. More specifically, the one-pass inkjet printing apparatus is configured such that a long recording head (line head) along the width of the recording medium is fixed and arranged, and the recording medium is conveyed directly under it. The line head ejects ink toward , and records an image line by line on the recording medium.

In a one-pass inkjet printing apparatus, the quality of a printed image is degraded unless a large number of ink ejection openings (ejection nozzles) are accurately arranged across the entire width of the recording medium in a direction intersecting the direction of relative movement of the recording medium. Manufacture of the line head requires precision, is difficult to manufacture, and is itself expensive. Therefore, in recent years, a one-pass inkjet printing apparatus has been proposed in which a long line head is configured by arranging a plurality of short head modules in the width direction of a recording medium so as to connect them.

In a one-pass inkjet printing apparatus having a plurality of such line heads spaced apart in the conveying direction of the recording medium, due to limitations in mechanical mounting accuracy, positional deviations between head modules in the same line head and different line heads may occur. There is a risk of positional deviation occurring between the heads.

In the image recording apparatus described in Japanese Patent Application Laid-Open No. 2002-200003, a correction pattern for obtaining intra-line head errors is recorded by a reference line head, and correction is performed by obtaining inter-line head errors by a reference line head and other line heads. Record the pattern. These correction patterns are read to obtain each error, the image recording timing of each head module of the reference line head is corrected based on the error within the line head, and each of the other line heads is corrected based on the error between the line heads. The image recording timing of the head module is corrected.

The image recording apparatus disclosed in Japanese Patent Application Laid-Open No. 2002-200010 includes detection means for detecting deviation between images recorded by different head modules, and correction means for correcting deviation between images based on the detection result of the detection means. ing. The misalignment between images also includes misalignment caused by the tilt of the head module.

JP 2015-66851 A JP 2005-53167 A

In the above-described conventional image recording apparatus, correction for achieving connection between images recorded by each head module in the same line head and between images recorded by corresponding head modules in different line heads It is not compatible with correction (color misregistration correction) that realizes matching of recording positions (in the transport direction).

In Patent Document 1, the error between line heads is acquired at one point representing the head module. Therefore, if the directions of the ejection nozzle arrays in the head modules corresponding to the line heads do not match (there is an inclination), the print position in the transport direction of the print medium cannot be corrected satisfactorily. In addition, since errors between line heads are corrected preferentially, errors within line heads are not corrected satisfactorily.

In Japanese Patent Application Laid-Open No. 2002-200010, it is necessary to grasp in advance the mounting error during manufacture of the detection sensor that acquires the inclination of each head module, and this mounting error prevents good correction. Further, correcting the deviation caused by the inclination of the head module affects the error between the line heads, and this effect is not corrected.

Therefore, the present invention provides correction for achieving connection between images recorded by each head module in the same line head, and correction for realizing matching of recording positions between images recorded by corresponding head modules of different line heads ( It is an object of the present invention to provide a recording position correction method, an image recording apparatus, and a recording position correction program that are compatible with color misregistration correction.

Furthermore, other objects of the present invention will become clear from the following description.

The above problems of the present invention are solved by the following inventions.

1.
A recording position correcting method for correcting an image recording position on a recording medium by each head module in an image recording apparatus having a first line head and a second line head, comprising:
The first line head is configured by arranging a plurality of short head modules in which a plurality of ejection nozzles are formed in a row in the direction of the ejection nozzle row. causing ink ejected from the ejection nozzle to land on the recording medium that is operated to move to
The second line head has a configuration similar to that of the first line head, is arranged apart from the first line head in the direction of relative movement of the recording medium, and is configured to eject the ink onto the recording medium. Let the ink ejected from the nozzle land,
printing a detection chart for detecting a positional error of the image recording position of each head module with respect to a reference position in the direction of relative movement of the recording medium, and a tilt error of the tilt of each head module with respect to a reference line;
reading the printed detection chart to acquire the position error and the tilt error of each of the head modules;
correcting the image recording timing of each of the head modules on the recording medium based on the acquired position error;
correcting the inclination of the recorded image to be recorded on the recording medium of each of the head modules based on the acquired inclination error;
A recording position correcting method, comprising: recorrecting the image recording timing of each of the head modules on the recording medium based on the correction of the inclination of the recorded image.
2.
correcting the image recording timing for each head module of the first line head;
correcting the inclination of the recorded image for each head module of the second line head with reference to each head module of the first line head;
2. The recording position correction method according to 1, wherein the re-correction of the image recording timing is performed for each head module of the second line head.
3.
3. The recording position correcting method according to 1 or 2, wherein the correction of the inclination of the recorded image corrects the recorded image to a shape that offsets the inclination error of the head module.
4.
4. The recording position correcting method according to 3 above, wherein the tilt correction of the recorded image is performed when the tilt error exceeds a predetermined allowable value.
5.
The inclination error of each head module of the second line head is an inclination error with respect to the ejection nozzle row of each head module of the first line head corresponding to each head module. 5. The recording position correction method according to any one of 1 to 4 above.
6.
The positional error of each head module of the first line head is the positional error of the other head module between adjacent head modules in the first line head with the position of one head module as a reference position. ,
The positional error of each head module of the second line head is a positional error with reference to the recording position after correction of the image recording timing by each head module of the first line head corresponding to each head module. 6. The recording position correcting method according to any one of 1 to 5, wherein:
7.
The detection chart is
a first detection pattern indicating a positional error of one head module between adjacent head modules in the same line head, with the position of the other head module as a reference position;
a second detection indicating a position error of each head module of the second line head with respect to a recording position by each head module of the first line head corresponding to each head module of the second line head; 7. The recording position correcting method according to 6 above, characterized by including at least a pattern.
8.
8. The recording position correcting method according to 7 above, wherein the first detection pattern and the second detection pattern have the same structure and are printed by two or more different head modules.
9.
9. The recording according to 7 or 8, wherein the first detection pattern of the second line head and the second detection pattern are printed at corresponding positions in the relative movement direction of the recording medium. Position correction method.
10.
The positional error of the first line head is the positional error of the adjacent head module with any one of the head modules of the first line head as the positional reference and the positional error of the adjacent head module with the adjacent head module as the positional reference. Furthermore, it includes both positional errors for adjacent head modules and positional errors for successively adjacent head modules with the most recent head module as a positional reference,
The positional error of each head module of the second line head is a positional error with reference to the recording position after correction of the image recording timing by each head module of the first line head corresponding to each head module. 6. The recording position correcting method according to any one of 1 to 5, wherein:
11.
The positional error of the first line head is the positional error of the adjacent head module with any one of the head modules of the first line head as the positional reference and the positional error of the adjacent head module with the adjacent head module as the positional reference. Furthermore, it includes both positional errors for adjacent head modules and positional errors for successively adjacent head modules with the most recent head module as a positional reference,
The positional error of the second line head includes the positional error of any one head module of the second line head with respect to any one head module of the first line head, and the positional error of the head module of any one of the first line heads. The positional error of the adjacent head module with any one of the two line heads as the positional reference, and the positional error of the further adjacent head module with the adjacent head module as the positional reference. 6. The recording position correcting method according to any one of 1 to 5 above, wherein the recording position correction method includes all positional errors with respect to the head module with the most recent head module as a positional reference.
12.
12. The recording position correction according to any one of 6 to 11, wherein the re-correction of the image recording timing is performed based on a position error obtained by adding a recording position variation amount caused by correction of the inclination of the recorded image. Method.
13.
13. The recording position correction method according to any one of 1 to 12, wherein the inclination error is calculated based on a difference between a position error near one end of each head module and a position error near the other end. .
14.
14. The recording position correcting method according to any one of 1 to 13, wherein the first line head ejects ink having a lower lightness than the ink ejected by the second line head.
15.
15. The recording position correcting method according to 14 above, wherein black ink is ejected from the first line head.
16.
A plurality of short head modules in which a plurality of ejection nozzles are formed in a row are arranged in the direction of the ejection nozzle row, and the ejection onto the recording medium is relatively moved in a direction intersecting the ejection nozzle row. a first line head that lands ink ejected from nozzles;
It has the same configuration as the first line head, is arranged apart from the first line head in the direction of relative movement of the recording medium, and causes ink ejected from the ejection nozzles to land on the recording medium. a second line head;
for detecting, by each line head, a positional error of the image recording position of each head module in the direction of relative movement of the recording medium with respect to a reference position, and an inclination error of each head module with respect to a reference line; detection chart printing means for printing the detection chart;
error acquisition means for reading the detection chart and acquiring the position error and the tilt error of each of the head modules;
recording timing correcting means for correcting the image recording timing of each of the head modules on the recording medium based on the position error;
image tilt correction means for correcting the tilt of the recording image recorded on the recording medium of each of the head modules based on the tilt error;
The image recording timing is corrected based on the position error by the recording timing correcting means, the tilt of the recorded image is corrected based on the tilt error by the image tilt correcting means, and the tilt of the recorded image is corrected based on the tilt correction of the recorded image. 7. An image recording apparatus, wherein image recording timing is re-corrected to correct image recording positions on said recording medium by said respective head modules.
17.
17. The image recording apparatus according to 16 above, characterized by executing the recording position correction method according to any one of 2 to 15 above.
18.
A program that is executed in a computer device and controls an image recording device,
16. A recording position correction program characterized by executing the recording position correction method according to any one of 1 to 15 above.

According to the present invention, correction for realizing connection between images recorded by each head module in the same line head and correction for realizing matching of recording positions between images recorded by corresponding head modules of different line heads. It is possible to provide a recording position correction method, an image recording apparatus, and a recording position correction program that are compatible with (color misregistration correction).

Schematic diagram showing the overall configuration of an image recording apparatus according to an embodiment FIG. 2A is a side view of the main part of the image recording apparatus, and FIG. Block diagram showing the configuration of the control unit of the image recording apparatus FIG. 4 is a diagram showing division of recorded image data in an image processing section of a control section of the image recording apparatus; Time chart showing control signals in the image recording device FIG. 4 shows a detection chart printed by the image recording apparatus; A diagram showing first and second detection patterns in the detection chart Diagram explaining how to obtain the position error Enlarged view of position error detection pattern Diagram explaining acquisition of position error for acquisition of tilt error Diagram explaining how to obtain the tilt error Diagram explaining tilt correction of the head module FIG. 3B shows the detection pattern (a) and the arrangement of the head module when there is no positional error or tilt error; FIG. 4(a) is a diagram showing a detection pattern (a) and an arrangement of a head module when there is a positional error and an inclination error; K-color straight line (a) corrected for position error and C-color straight line (b) corrected for position error and tilt error Flowchart showing a procedure for correcting a position error and a tilt error

An image recording apparatus according to an embodiment of the present invention will be described below with reference to the drawings. The recording position correction method according to the embodiment of the present invention is embodied as the operation of this image recording apparatus, and is implemented by the image recording apparatus executing the recording position correction program according to the embodiment of the present invention. be done. However, the scope of the invention is not limited to the illustrated examples. In the following description, parts having the same functions and configurations are denoted by the same reference numerals, and their description may be omitted.

[Configuration of image recording device]
FIG. 1 is a schematic diagram showing the overall configuration of an image recording apparatus according to an embodiment.

As shown in FIG. 1, the image recording apparatus 1 includes a paper feeding section 10, an image forming section 20 which also serves as detection chart printing means, a paper discharging section 30, a control section 40, and an ink supplying section 50. there is In the image recording apparatus 1 , under the control of the control unit 40 , the recording medium P transported from the paper feeding unit 10 to the image forming unit 20 is coated with the ink supplied from the ink supply unit 50 in the image forming unit 20 . After forming the image, the recording medium P is ejected to the paper ejection section 30 .

The paper feeding section 10 holds a recording medium P on which image formation is to be performed, and supplies this recording medium P to the image forming section 20 . The paper feed section 10 has a paper feed tray 11 and a transport section 12 .

The paper feed tray 11 is a plate-like member provided so that one or a plurality of recording media P can be stacked and placed. The paper feed tray 11 is provided so as to move up and down according to the amount of the recording medium P placed thereon, and is held at a position where the recording medium P is transported by the transport unit 12 .

The transport unit 12 has a transport mechanism that rotates a ring-shaped belt 123 with a plurality of (for example, two) rollers 121 and 122 to transport the recording medium P on the belt 123 , and the paper feed tray 11 . It has a supply unit for transferring the recording medium P to the belt 123 . The conveying unit 12 conveys the recording medium P transferred to the belt 123 by the supply unit by rotating the belt 123 .

The image forming section 20 ejects ink onto the transported recording medium P to form an image. The image forming section 20 has a delivery unit 22 , a paper heating section 23 , a conveying drum 21 , an inkjet head 24 , a fixing section 25 , a delivery section 26 and a paper sensor 27 .

The delivery unit 22 is provided at a position between the transporting section 12 of the paper feeding section 10 and the transporting drum 21 , and delivers the recording medium P transported by the transporting section 12 to the transporting drum 21 . The delivery unit 22 includes a swing arm section 221 that carries one end of the recording medium P transported by the transport section 12 , and a cylindrical delivery drum 222 that delivers the recording medium P carried by the swing arm section 221 to the transport drum 21 . etc. The transfer unit 22 picks up the recording medium P on the conveying section 12 by the swing arm section 221 , transfers it to the transfer drum 222 , guides the recording medium P along the outer peripheral surface of the conveying drum 21 , and transfers it to the conveying drum 21 . hand over.

The paper heating section 23 heats the recording medium P carried by the conveying drum 21 . The paper heating unit 23 has, for example, an infrared heater or the like, and generates heat in response to energization. The paper heating unit 23 is provided in the vicinity of the outer peripheral surface of the transport drum 21 and on the upstream side of the inkjet head 24 in the transport direction of the recording medium P by the rotation of the transport drum 21 . The heat generation of the paper heating unit 23 is controlled by the control unit 40 so that the recording medium P carried by the conveying drum 21 and passing near the paper heating unit 23 reaches a predetermined temperature.

The transport drum 21 carries the recording medium P along the cylindrical outer peripheral surface, transports the recording medium P by being rotated, and moves the recording medium P relative to the inkjet head 24 . The conveying surface of the conveying drum 21 faces the paper heating section 23, the inkjet head 24, and the fixing section 25 so that the processing related to image formation is sequentially performed on the recording medium P being conveyed.

The inkjet head 24 ejects ink onto the recording medium P carried by the transport drum 21 to form an image. The inkjet heads 24 are individually provided for each of the colors C (cyan), M (magenta), Y (yellow), and K (black). In FIG. 1, the ink jet heads 24 corresponding to the respective colors of Y, M, C, and K are sequentially provided from the upstream in the conveying direction of the recording medium P conveyed by the rotation of the conveying drum 21 .

The inkjet head 24 is provided with a length (width) that covers the entire width of the recording medium P in the direction perpendicular to the conveying direction of the recording medium P (width direction). That is, the image recording apparatus 1 in this embodiment is a one-pass type line head type image recording apparatus. The inkjet head 24 is composed of four line heads. In the present invention, one of the line heads is the "first line head" and the other line head is the "second line head".

The first line head (K (black)) is configured by arranging a plurality of short head modules in which a plurality of ejection nozzles are formed in a row in the direction of the ejection nozzle row. Ink ejected from ejection nozzles is caused to land on the recording medium P that is relatively moved. The second line head (C (cyan), M (magenta), Y (yellow)) has a configuration similar to that of the first line head, and has a relative movement direction of the recording medium P from the first line head. are spaced apart.

The fixing unit 25 irradiates the recording device P with an energy beam for curing the ink after the ink is ejected onto the recording medium P by the inkjet head 24 . The fixing unit 25 has, for example, a fluorescent tube such as a low-pressure mercury lamp, and emits energy rays such as ultraviolet rays by causing the fluorescent tube to emit light. The fixing unit 25 is provided in the vicinity of the outer peripheral surface of the transport drum 21 and downstream of the inkjet head 24 in the direction in which the recording medium P is transported by the rotation of the transport drum 21 . The fixing unit 25 irradiates the recording medium P carried by the conveying drum 21 onto which ink has been ejected, with energy rays, and cures the ink ejected onto the recording medium P by the action of the energy rays.

Fluorescent tubes that emit ultraviolet rays include, in addition to low-pressure mercury lamps, mercury lamps with an operating pressure of several hundred Pa to 1 MPa, light sources that can be used as germicidal lamps, cold cathode tubes, ultraviolet laser light sources, metal halide lamps, light-emitting diodes, etc. is mentioned. Among these, a light source (for example, a light-emitting diode, etc.) that can irradiate ultraviolet light with a higher illuminance and consumes less power is desirable. Moreover, the energy beam is not limited to ultraviolet rays, and any energy beam having the property of curing the ink according to the properties of the ink may be used, and the light source can also be selected according to the wavelength of the energy beam.

The delivery section 26 conveys the recording medium P irradiated with the energy beam from the fixing section 25 from the conveying drum 21 to the paper discharge section 30 . The delivery unit 26 includes a conveying mechanism that conveys the recording medium P on the belt 263 by rotationally driving a ring-shaped belt 263 with a plurality of (for example, two) rollers 261 and 262 , and conveys the recording medium P from the conveying drum 21 . It has a cylindrical delivery drum 264 and the like for delivery to the mechanism. The delivery section 26 transports the recording medium P delivered to the belt 263 by the delivery drum 264 by the belt 263 and delivers it to the paper ejection section 30 .

A paper sensor 27 detects the recording medium P held by the transport drum 21 . The paper sensor 27 is, for example, a light reflective sensor.

The paper discharge section 30 stores the recording medium P delivered from the image forming section 20 by the delivery section 26 . The paper discharge unit 30 has a plate-like paper discharge tray 31 and the like, and the recording medium P after image formation is stacked on the paper discharge tray 31 .

The ink supply unit 50 reserves ink, supplies this ink to the inkjet head 24 of the image forming unit 20 , and makes it possible to eject each color of ink from the ejection nozzles of the inkjet head 24 .

The ink used in the image recording apparatus 1 of the present embodiment is not particularly limited, but is, for example, an ultraviolet (UV) curable ink. This UV curable ink undergoes a phase change between a gel state and a sol (liquid) state depending on the temperature when not irradiated with UV rays. For example, this ink has a phase change temperature of about 40° C. to 100° C., and is uniformly solified (liquefied) when heated above this phase change temperature. On the other hand, the ink gels below a certain temperature, including around normal room temperature (0° C. to 30° C.).

In the image recording apparatus of this embodiment, four ink jet heads 24 are provided corresponding to each of C, M, Y, and K colors, but the number of ink jet heads 24 is not limited in any way and may be increased. A larger number of inkjet heads may be provided to correspond to different colors. The ink ejection method of the inkjet head 24 is not limited at all, and any known method of inkjet head may be used. Further, in this image recording apparatus, the recording device P is conveyed by the rotation of the conveying drum 21, but the recording device P may be conveyed while being maintained in a flat state by using a belt, rollers, or the like. Alternatively, the recording apparatus P may be fixed, and the inkjet head 24 may be conveyed and moved relative to the recording medium P.

[Arrangement of line head]
FIG. 2 is a side view (a) of the main part of the image recording apparatus and a plan view (b) of the conveying drum viewed from above the line head.

As shown in FIGS. 2A and 2B, each of the line heads Y, M, C, and K includes a plurality of short head modules in which a plurality of ejection nozzles are formed in a row, arranged in the ejection nozzle row direction. configured as follows. In this embodiment, each line head Y, M, C, and K is composed of four head modules Y-1 to 4, M-1 to 4, C-1 to 4, and K-1 to 4, respectively. . Each head module is attached to an attachment member.

Each of the head modules Y-1-4, M-1-4, C-1-4, and K-1-4 incorporates a plurality of recording elements. Each recording element includes a pressure chamber that stores ink, a piezoelectric element provided on the wall surface of the pressure chamber, and an ejection nozzle. When a drive voltage is applied from the drive circuit of the head module to the piezoelectric element, the pressure in the pressure chamber changes according to the magnitude of the drive voltage, and ink is ejected from the ejection nozzle communicating with the pressure chamber. In FIG. 2B, the ejection nozzles of the head modules Y-1 to Y-4, M-1 to 4, C-1 to 4, and K-1 to K-4 are drawn as dots. The ejection nozzles of each of the head modules Y-1 to Y-4, M-1 to 4, C-1 to 4, and K-1 to K-4 are open on the side facing the conveying drum 21 (ink ejection surface).

A plurality of ejection nozzles provided in each of the head modules Y-1 to Y-4, M-1 to 4, C-1 to 4, and K-1 to 4 are arranged on the side facing the transport drum 21 in the transport direction of the recording medium P ( They are arranged at regular intervals across the recording width (for example, 300 mm) of the recording medium P in the width direction (X direction) orthogonal to the Y direction).

Each of the four head modules Y-1 to 4, M-1 to 4, C-1 to 4, and K-1 to 4 that constitute each of the line heads Y, M, C, and K has an arrangement range in the X direction of The recording elements of the first and third head modules, and the second and fourth head modules, which partially overlap each other, are located on the same line along the X direction, and are arranged in a houndstooth pattern with an interval Dn in the Y direction. there is The ends of the head modules overlap the ends of adjacent head modules in the Y direction. Each of the head modules Y-1 to 4, M-1 to 4, C-1 to 4, and K-1 to 4 includes, for example, 3584 recording elements, and the recording elements overlapping adjacent head modules in the Y direction are , for example 54.

The arrangement range in the X direction of the recording elements included in each of the line heads Y, M, C, and K is the width in the X direction of the area where an image is recorded on the recording medium P held and conveyed by the conveying drum 21. I have it covered. Each of the line heads Y, M, C, and K is used with its position fixed with respect to the conveying drum 21, as described above, at least during image recording.

In this image recording apparatus 1, the recording resolution in the X direction and the Y direction of each line head Y, M, C, K is, for example, 1200 dpi, and each head module Y-1 to Y-4, M-1 to Y-4, C- The recording elements 1 to 4 and K-1 to 4 are arranged at a density of 1200 per inch in the X direction.

The fixing unit 25 has an ultraviolet LED lamp, and irradiates the recording medium P held on the outer peripheral surface of the conveying drum 21 with ultraviolet light emitted by the ultraviolet LED lamp to cure the ink ejected onto the recording medium P. Let it settle. The fixing section 25 is arranged downstream of each of the line heads Y, M, C, and K in the transport direction of the recording medium P. As shown in FIG.

Further downstream of the fixing section 25 in the direction in which the recording medium P is conveyed, an in-line sensor 28 constituting error acquisition means is arranged. The in-line sensor 28 is arranged facing the outer peripheral surface of the transport drum 21, captures an image recorded on the recording medium P held and transported by the transport drum 21, and outputs two-dimensional image data. The in-line sensor 28 is a CCD sensor having a plurality of imaging elements arranged at predetermined intervals in the width direction (X direction) of the recording medium P. The CCD sensor outputs a signal corresponding to the intensity of light emitted from a light source (not shown) and reflected by the surface of the recording medium P. FIG. The in-line sensor 28 also includes a circuit that converts an analog signal output from the imaging device into a digital signal and outputs the digital signal to the control unit 40 .

The resolution of the imaging data output from the inline sensor 28 in the width direction (X direction) of the recording medium P is, for example, 600 dpi, and the resolution in the transport direction (Y direction) of the recording medium P is, for example, 300 dpi.

The line heads Y, M, C, and K and the in-line sensor 28 are positioned at distances Dy, Dm, Dc, Dk, and Ds from the paper sensor 27 arranged along the outer peripheral surface of the conveying drum 21. are placed.

FIG. 3 is a block diagram showing the configuration of the control section of the image recording apparatus.

The control unit 40 has a CPU 401 as shown in FIG. The CPU 401 centrally controls the overall operation of the image recording apparatus 1 and executes various calculations and controls. A RAM 402 and a ROM 403 are connected to the CPU 401 . The RAM 402 provides a working memory space to the CPU 401 and stores temporary data. The ROM 403 stores programs for various controls executed by the CPU 401, setting data, and the like. An interface 404 connected to the CPU 401 is means for transmitting and receiving data to and from the external device 60, and is configured by either various serial interfaces or various parallel interfaces, or a combination thereof.

An image input unit 405 is connected to the external device 60 . The image input unit 405 is means for receiving print image data from the external device 60, and is configured by either various serial interfaces or various parallel interfaces, or a combination thereof. The recorded image data received by the image input unit 405 is sent to the image processing unit 406 which also functions as an image tilt correcting unit.

The image processing unit 406 performs image processing such as halftone processing on the recording image data input from the external device 60, and processes the head modules Y-1 to Y-4, M-1 to Y4, C -1 to 4 and K-1 to 4 are divided into recorded image data.

FIG. 4 is a diagram showing division of recorded image data in the image processing section of the control section of the image recording apparatus.

As shown in FIG. 4, the image processing unit 406 converts the input recording image data into recording data for each of the head modules Y-1 to 4, M-1 to 4, C-1 to 4, and K-1 to 4. Divide into image data. That is, the image processing unit 406 first color-separates the input recorded image data into data of a Y-color recorded image, an M-color recorded image, a C-color recorded image, and a K-color recorded image. . Next, the image processing unit 406 converts the recorded image data of each color into recorded image data for each of the head modules Y-1 to 4, M-1 to 4, C-1 to 4, and K-1 to 4. To divide.

As shown in FIG. 3, the image data divided into recording image data for each of the head modules Y-1 to 4, M-1 to 4, C-1 to 4, and K-1 to 4 are processed by the recording timing correcting means. It is sent to the associated image recording control unit 407 . The image recording control unit 407 divides the recording image data for each of the head modules Y-1 to 4, M-1 to 4, C-1 to 4, and K-1 to K-4 input from the image processing unit 406. Image data is temporarily stored and sent to each line head (inkjet recording section) Y, M, C, and K according to an image recording control signal input from the control signal generation section 408 .

A mechanism control unit 409 connected to the CPU 401 controls an inkjet mechanism unit 410 such as a motor for rotating the conveying drum 21 based on commands from the CPU 401 and control signals input from the control signal generation unit 408 .

The in-line sensor control circuit 411 connected to the CPU 401 outputs a control signal for causing the in-line sensor 28 to perform imaging at a predetermined timing based on the command from the CPU 401 and the control signal input from the control signal generation unit 408. Output to line sensor 28 .

A read image memory 412 connected to the CPU 401 stores image data captured by the in-line sensor 28 .

FIG. 5 is a time chart showing control signals in the image recording apparatus.

The control signal output from the control signal generator 408 is generated based on the ink ejection clock, as shown in FIG. The ink discharge clock is recorded at a predetermined recording resolution (1200 dpi) in the transport direction (Y direction) by each of the head modules Y-1 to 4, M-1 to 4, C-1 to 4, and K-1 to 4. This is a clock signal indicating ink ejection timing for printing.

The control signals also include an ILS (in-line sensor) image acquisition clock. The ILS image acquisition clock is a clock signal indicating image acquisition timing for acquiring an image with a predetermined resolution (300 dpi) in the transport direction (Y direction) of the in-line sensor 28 .

The control signal also includes an ILS (in-line sensor) image acquisition period signal. The ILS image acquisition period signal is a signal that indicates the period during which the in-line sensor 28 acquires an image.

The control signal includes a paper sensor signal. The paper sensor signal is a signal indicating that the paper sensor 27 has detected the leading edge and the trailing edge of the recording medium P (length L) on the conveying drum 21 .

The control signal includes a recording period signal for controlling the recording period for each of the head modules Y-1-4, M-1-4, C-1-4, and K-1-4. The recording period signal is a signal that indicates the ink ejection (image recording) period for each of the head modules Y-1 to Y-4, M-1 to 4, C-1 to 4, and K-1 to K-4. During the ink ejection period, print image data is sent to each of the head modules Y-1-4, M-1-4, C-1-4, and K-1-4.

In the image recording apparatus 1 of this embodiment configured as described above, when the recording position correction method is executed, the ink jet head 24 is used as a detection chart printing means, and each of the line heads Y, M, C, and K is printed. Thus, the position error of the image recording position of each head module Y-1 to Y-4, M-1 to Y-4, C-1 to Y-4, K-1 to K-4 in the transport direction (Y direction) of the recording medium P with respect to the reference position and , inclination error with respect to the reference line (ejection nozzle row) of the inclination of each head module Y-1 to 4, M-1 to 4, C-1 to 4, and K-1 to 4, and a detection chart for detecting Print.

The detection chart printed by the image recording device is as per the image data if there is no position error or tilt error in each head module Y-1 to 4, M-1 to 4, C-1 to 4, and K-1 to 4. Although it is printed in a correct shape, it is printed in a shape different from that of the image data due to positional and tilt errors. Detecting the position error and inclination error of each head module Y-1~4, M-1~4, C-1~4, K-1~4 by detecting the difference with respect to the image data in the printed detection chart. can do.

FIG. 6 is a diagram showing a detection chart printed by the image recording apparatus.

The detection chart printed by the image recording apparatus, as shown in FIG. has a first detection pattern for detecting a positional error between adjacent head modules. The first detection pattern indicates the positional error of one head module between adjacent head modules in the same line head, with the position of the other head module as the reference position.

In addition, the detection chart is based on the recording position of K color near the end of the recording area of each head module of the second line head (colors Y, M, and C) excluding the first line head (color K). It has a second sensing pattern for sensing positional errors between the colors. The second detection pattern indicates the position error of each head module of the second line head with respect to the recording position by each head module of the first line head corresponding to each head module of the second line head. It is.

By printing the position error detection patterns (the first detection pattern and the second detection pattern) of the same line head at the same positions in the transport direction of the recording medium P (arranged in the width direction), the recording medium P Disturbance factors such as minute fluctuations in the conveying speed of the sheet can be reduced.

In this recording position correction method, as will be described later, the position error for the first line head (K color) is determined by any one of the head modules K-1 to K-4 of the first line head (K color). positional errors for adjacent head modules K-1 to K-4 as positional references, and positional errors for further adjacent head modules K-1 to K-4 with these adjacent head modules K-1 to K-4 as positional references; positional errors of sequentially adjacent head modules K-1 to K-4 with the most recent head modules K-1 to K-4 as positional references.

Further, the position errors of the head modules Y-1 to 4, M-1 to 4, and C-1 to 4 of the second line heads (Y color, M color, and C color) are the respective head modules Y-1 to 4, M-1 to 4, C-1 to C-4, the first line head (K color) head modules K-1 to 4 correct the recording position after the image recording timing is used as the reference position. Errors are preferred.

Furthermore, the positional error for the second line head (Y, M, C) is calculated using any one of the head modules K-1 to K-4 of the first line head (K) as a position reference. 2 line heads (Y color, M color, C color), the position error of any one of the head modules Y-1 to 4, M-1 to 4, C-1 to 4, and the second line head (Y Adjacent head modules Y-1 to 4, M-1 with any one of the head modules Y-1 to 4, M-1 to 4, C-1 to 4 as the position reference ∼ 4, C-1 to 4, and the adjacent head modules Y-1 to Y-1 to which the adjacent head modules Y-1 to 4, M-1 to 4, C-1 to 4 are the positional references. 4, M-1 to 4, C-1 to 4 positional errors, and sequentially adjacent head modules Y-1 to Y-4, M-1 to 4, C-1 to 4, the latest head modules are positional references. It is preferable to include all positional errors such as .

FIG. 7 is a diagram showing first and second detection patterns in the detection chart.

The first detection pattern (positional error detection pattern between adjacent head modules) and the second detection pattern (positional error detection pattern between colors) have the same structure as shown in FIG. A plurality of position detection lines are printed at regular intervals in prescribed positions in an area surrounded by four positioning marks by the module and the error detection side head module. The position detection lines by the error detection head module are recorded at intervals (for example, 16 line intervals and 18 line intervals) different from the position detection lines by the reference side head module. A virtual line number is given to each of the position detection line by the reference side head module and the position detection line by the error detection side head module. Among the position detection lines by the reference side head module and the position detection lines by the error detection side head module, the central detection line (virtual line number 0) corresponds to the position of the recording medium P in the transport direction (Y direction) when there is no position error. are consistent.

In the position error detection pattern shown in FIG. 7, the difference in the recording interval between the position detection line by the reference side head module and the position detection line by the error detection side head module is two lines, and the center detection line (virtual line number 0) is A virtual line number that increases or decreases by 2 is assigned to each line. In this embodiment, the virtual line number is incremented or decremented by 2 (integer value), but the increment or decrement value is not limited, and the position error is not necessarily an integer value.

[Detection of position error]
Acquisition of the position error will be described below.
FIG. 8 is a diagram for explaining a method of acquiring a position error.

First, as shown in FIG. 8(a), from the image of the detection chart read by the in-line sensor 28, a rectangular area including each position error detection pattern is cut out. The positions of these rectangular areas are known in advance. Next, the positional error of the positional detection line by the error detection side head module is detected with reference to the positional detection line by the reference side head module. As shown in FIG. 8B, position error detection is performed by obtaining the coordinates (Y coordinates) of each position detection line on the reference side and the error detection side from a rectangular area image including the position error detection pattern, and calculating the virtual line number is used as the x-axis for one-dimensional approximation (linear approximation). A virtual line number of the intersection of two one-dimensional approximations (linear approximations) is calculated, and the sign of the calculated number is reversed to be the positional error of the error detection side head module with respect to the reference side head module.

Both the positional error between adjacent head modules and the positional error between colors can be determined in a similar manner.

FIG. 9 is an enlarged view of the position error detection pattern.

In order to acquire the coordinates of the detection line from the read image of the position error detection pattern shown in FIG. 9A, as shown in FIG. It is assumed that a detection line exists in an area where the luminance is smaller (darker) than the threshold value, and the density barycentric coordinates (Y coordinates) obtained by inverting the luminance value of this area are obtained, and these coordinates are used as the coordinates of the detection line.

The positional error between colors is preferably obtained by using the color material (K color) that has the largest luminance amplitude (lowest lightness) in the read image of the detection line as the reference color. This is because the read image of the detection line with the coloring material having the largest luminance amplitude is less affected by fluctuations (noise components) caused by the surface state (fine unevenness) of the recording medium P and the like. Note that FIG. 9 shows only two detection lines. Also, the coordinates of the detection line are not necessarily integer values.

[Correction of position error]
In this image recording apparatus 1, the control signal generation unit 408 is used as a recording timing correcting means, and based on the position error, each of the head modules Y-1 to 4, M-1 to 4, C-1 to 4, K By changing the timing of each recording period of -1 to -4, it is possible to correct the image recording position of each recording medium P in the conveying direction.

[Detection of inclination error]
A method of detecting an inclination error of the C-color head modules C-1 to C-4 will be described with reference to the K-color head modules K-1 to K-4.
10A and 10B are diagrams for explaining the acquisition of the position error for acquiring the tilt error. FIG.

As shown in FIG. 10, from the position error detection patterns between CK on the left end side and the right end side of the head module C, the position error of C color with reference to K color is detected. In FIG. 10, (+2) and (-2) are detected.

11A and 11B are diagrams for explaining a method of obtaining a tilt error. FIG.

As shown in FIG. 11(a), when the positional errors (K color reference) on the left end side and the right end side of the head module C for C color are (+2) and (−2), FIG. 11(b) shows As shown, the left end side and the right end side of the head module C, whichever has the larger positional error, is set as the "C tilt reference point" and converted into the tilt error of the head module C. FIG. In FIG. 11(b), the tilt error is (-4). By such conversion, the tilt correction direction can be limited to one direction. By setting the end with a large positional error as the "tilt reference point", the direction to be corrected is limited to one direction (+). Although the position error is illustrated as an integer value here, the position error is not necessarily an integer value as described above.

[Correction of inclination error]
In this image recording apparatus 1, as shown in FIG. 11C, tilt correction is performed based on the obtained tilt error. The tilt correction is performed by correcting the tilt of the recorded image recorded on the recording medium P of the head module C (correcting the recorded image into a rhombic shape) using the image processing unit 406 as an image tilt correcting means.

When the inclination error is corrected with reference to the reference line (ejection nozzle row) of the reference head module K, as shown in FIG. A state is created in which there is only a positional error with the head module K as a reference. It is preferable to correct the position by changing the image recording timing of the head module C as shown in FIG. 11(d).

FIG. 12 is a diagram for explaining tilt correction of the head module.

In the recorded image data divided for each head module as described above, the tilt correction of the recorded image data of the module requiring tilt correction is performed in units of integer lines, as shown in FIG. Therefore, the necessary correction amount between the left end and the right end is proportionally divided by the print image data width, rounded (rounded off) to a nearest integer value, and the print image data is shifted in the correction direction.

It should be noted that tilt correction of the recorded image data divided for each head module is correction processing of the entire image data, and the load such as processing time may increase. In that case, if it is determined that the permissible value for color misregistration on the printed image is satisfied even if the correction of a minute (for example, less than 0.1 mm) tilt of the head module is omitted, the tilt of the recorded image data can be corrected. Correction may be performed only when the tilt error of the head module exceeds a predetermined allowable value.

[Correction of Position Error and Tilt Error]
In this image recording apparatus 1, the in-line sensor 28 is used as error acquisition means to read the detection chart, and the respective head modules Y-1 to 4, M-1 to 4, C-1 to 4, and K-1 to 4 are detected. Obtain position and tilt errors. Next, using the control signal generator 408 as recording timing correction means, the image recording timing of each of the head modules K-1 to K-4 of the first line head (K color) is adjusted based on the acquired position error. By changing, the image recording position of each recording medium P in the conveying direction is corrected. Further, using the image processing unit 406 as an image tilt correction means, each head module Y-1 to Y-4, M of the second line head (Y color, M color, C color) is calculated based on the acquired tilt error. -1 to C-4 and C-1 to C-4 to correct the inclination of the recorded image recorded on each of the recording media P.

When the inclination error is corrected as described above, both the left end side and the right end side of the head module are in a state of having only a positional error based on the reference head module (K color). Further, it is preferable to correct the position error by changing the image recording timing of each head module.

That is, in the image recording apparatus 1, the recording timing correcting means corrects the image recording timing based on the position error, and the image tilt correcting means corrects the tilt of the recorded image based on the tilt error. Based on the correction, the image recording timing is re-corrected, and each head module Y-1 to Y-4, M-1 to C-4, C-1 to C-4 of the second line head (Y color, M color, C color). It is preferable to recorrect the image recording position on the recording medium P by .

Specific procedures for position correction and tilt error will be described below.
FIG. 13 is a diagram (b) showing the arrangement of the detection pattern (a) and the head module when there is no positional error or inclination error.
13 to 16, the thin solid line represents a straight line of K color in the width direction of the recording medium P, and the thick dashed line represents a straight line of C color in the width direction of the recording medium P. FIG. Note that the positional error in the conveying direction of the recording medium P is exaggerated. Also, although the error detection values are shown as integer values, the detection values are not necessarily integer values.

In this example, it is assumed that the reference first line head is for K color and the second line head is for C color. The Y-color and M-color line heads can also be corrected in the same manner as the C-color line head in this example.

As shown in FIG. 13, when there is no position error or tilt error in the first line head (K color) and the second line head (C color), the K color printed by these line heads K and C is Neither the straight line nor the C-color straight line causes misalignment or inclination.

FIG. 14 is a diagram (b) showing the arrangement of the detection pattern (a) and the head module when there is a positional error and an inclination error.

As shown in FIG. 14, there is a positional error at the boundary between the adjacent head modules K-1 and K-2. A case where the module K-3 is tilted with respect to the other head modules K-2 and K-4 will be described. A positional error and a tilt error corresponding to these positional deviations and tilts appear in the K-color straight line.

A positional accuracy of ±0.2 mm or less can be achieved by adjusting the positions of the head module and the line head during mounting. , there is a positional error at the boundary of the head module, and when a regular pattern such as a halftone screen is printed at that position, even if the positional error is minute (for example, about 0.05 mm), the regularity is easily visible because it collapses. Also, when there is a positional error between different colors, such as between C color and K color shown in FIG. 14, even if the difference is minute (for example, about 0.1 mm), the printed image This is visually recognized as color shift.

On the other hand, when the head module K-3 is tilted with respect to the other head modules K-2 and K-4 shown in FIG. With respect to the recorded straight lines (about 70 mm each), the inclination corresponding to the mounting position accuracy is almost invisible.

FIG. 15 shows a K-color straight line (a) corrected for position errors and a C-color straight line (b) corrected for position errors and inclination errors.

Therefore, for the first line head (K color), as shown in FIG. 15A, only the positional error of the head module is corrected so that the straight line for K color does not have a step at the boundary between the head modules. , and for the second line head (color C), as shown in FIG. It is preferable to perform "color misregistration correction" on the basis of color).

As described above, in this recording position correction method, image recording apparatus, and recording position correction program, each head module Y-1 to 4, M-1 to 4, C-1 to 4, K in the same line head Correction that realizes connection between images recorded by -1 to 4, and corresponding head modules Y-1 to 4, M-1 to 4, C-1 to 4, and K-1 to 4 of different line heads record It is also possible to achieve compatibility with correction (color shift correction) that realizes matching of recording positions between images.

[Correction of specific numerical values of position error and inclination error]
The procedure for position correction and tilt error will be described below using specific numerical values. Numerical values in the description are examples and are not numerical values that limit the invention. In this embodiment, the center position of the recording medium P in the width direction is used as the position reference for each line head.

In this example, it is assumed that the reference first line head is for K color and the second line head is for C color. The Y-color and M-color line heads can also be corrected in the same manner as the C-color line head in this example.

First, as shown in [Table 1], the positional error between the adjacent head modules (HM) of the first line head (K color) is detected.

Next, as shown in [Table 2], the position error between the adjacent head modules of the second line head (color C) is detected.

As shown in [Table 3], the inter-color position error between the first line head (K color) and the second line head (C color) is detected.

Using the detected values in [Table 3], as shown in [Table 4], the larger position error is set as the "C tilt reference point" and converted into a "C tilt error".

From the numerical values in [Table 4], as shown in [Table 5], a correction amount that cancels out the "C tilt error" is determined.

As shown in [Table 6], using the correction results based on the correction amounts in [Table 5], the "positional error (detected value )” is corrected. This correction is performed by subtracting the C color right end conversion tilt (Table 5-C-1 right end to C-3 right end) from the position error (Table 2), and C color left end conversion tilt (Table 5-C-2 left end to C- 4 left edge) to the position error (Table 2).

As shown in [Table 7], using the correction results based on the correction amounts in [Table 5], "first line head (K color) and second line head (C color)" in [Table 3] position error (detection value) between colors. In this correction, the correction amounts of the left and right ends of C color (Table 5-C-1 left end to C-4 left end, C-1 right end to C-4 right end) are added to the position errors (Table 3).

As a result of such correction of the "inter-color positional error between the first line head (K color) and the second line head (C color)", the positional error at the left and right ends of the head module becomes the same. A unique "positional error between the colors of the first line head (K color) and the second line head (C color)" is obtained for each head module without discrimination.

Since there is no distinction between the left and right ends, as shown in [Table 8], the "first line head (K color) and second line head (C color)" reflecting the C color tilt correction (Table 5) positional error between colors" is obtained.

"Position error (detected value) between adjacent head modules of first line head (K color)" in [Table 1] and "Adjacent head module of second line head (C color)" in [Table 6] Positional error between modules (correction value reflecting C tilt error (Table 5))” and “Color between first line head (K color) and second line head (C color) in [Table 8] The amount of correction of the image recording timing is determined for each head module based on the positional error (correction value reflecting the C tilt correction (Table 5)) between the positions.

[Procedure (1) for determining correction amount of image recording timing]
As shown in [Table 9], from the positional errors (detected values) in [Table 1], the positional errors of the other head modules K-1, K-2, and K-4 with the head module K-3 as the reference position. Ask for

As shown in [Table 10], from the positional errors (correction values) in [Table 6], the positional errors of the other head modules C-1, C-2, and C-4 with the head module C-3 as the reference position. Ask for

As shown in [Table 11], the position error between colors between head modules C-3 and K-3 corrected by reflecting the C tilt correction in [Table 8] is added to the position error in [Table 10]. Then, the positional errors of the head modules C-1, C-2, C-3, and C-4 of the second line head (C color) with the head module K-3 as a reference are obtained.

As shown in [Table 12], from [Table 9] and [Table 11], each head module K-1, K-2, K- 4, determine the amount of correction for the image recording timings of C-1, C-2, C-3, and C-4.

Since the correction amount that can actually be set is an integer value for each line, if the correction amount of the image recording timing determined here is not an integer value, the nearest integer value is adopted as the correction amount.

[Procedure (2) for determining correction amount of image recording timing]
As shown in [Table 13], from the positional errors (detected values) in [Table 1], the positional errors of the other head modules K-1, K-2, and K-4 with the head module K-3 as the reference position. Ask for

As shown in [Table 14], when the positional errors (correction values) between colors in [Table 8] are added to the positional errors between adjacent head modules in [Table 13], the head module K-3 is positioned at the reference position. Positional errors of the head modules C-1, C-2, C-3, and C-4 of the second line head (color C) are obtained.

As shown in [Table 15], from [Table 13] and [Table 14], each head module K-1, K-2, K- 4, determine the amount of correction for the image recording timings of C-1, C-2, C-3, and C-4.

Since the correction amount that can actually be set is an integer value for each line, if the correction amount of the image recording timing determined here is not an integer value, the nearest integer value is adopted as the correction amount.

[Operation of recording position correction method]
FIG. 17 is a flow chart showing the procedure for correcting the position error and the tilt error.

When the recording position correction method is executed in this image recording apparatus 1, as shown in FIG. 17, recording position correction is started in S1, a detection chart is printed in S2, and the process proceeds to S3.

In S3, the detection chart is read, and the process proceeds to S4. In S4, a detection pattern is cut out, error detection is started, and the process proceeds to S5. In S5, the tilt correction amount of each head module of the second line head (Y color, M color, C color) is calculated, and the process proceeds to S6. In S6, inclination correction of the recorded image data is performed by each head module of the second line head (Y color, M color, C color), and the process proceeds to S7. In S7, the detected value of the position error is corrected, and the process proceeds to S11 or S21.

In S8, the amount of correction of the image recording timing is determined, and the process proceeds to S9 and ends.

In S11, the calculation of the positional error between the head modules is started, and the process proceeds to S12. In S12, positional errors between adjacent head modules in the second line head (Y color, M color, C color) are calculated, and the process proceeds to S13. In S13, the inter-color position error of the representative head modules of the second line head (Y color, M color, C color) is added, and the process proceeds to S8.

In S21, the calculation of the positional error between the head modules is started, and the process proceeds to S22. In S22, the position error between adjacent head modules in the first line head (K color) is calculated, and the process proceeds to S23. In S23, the inter-color position error of each head module of the second line head (Y color, M color, C color) is added, and the process proceeds to S8.

Reference Signs List 1 inkjet recording device 10 paper feeding unit 20 image forming unit 21 conveying drum 23 paper heating unit 24 inkjet head 25 fixing unit 27 paper sensor 28 inline sensor 30 paper discharging unit 40 control unit 50 ink supply unit 406 image processing unit 407 image recording control Unit 409 mechanism control unit Y second line head Y-1 to 4 head module M second line head M-1 to 4 head module C second line head C-1 to 4 head module K first line head K-1 to 4 Head module P Recording medium X Width direction Y Conveying direction

Claims (17)

A recording position correcting method for correcting an image recording position on a recording medium by each line head in an image recording apparatus having a first line head and a second line head, comprising:
The first line head is configured by arranging a plurality of short head modules in which a plurality of ejection nozzles are formed in a row in the direction of the ejection nozzle row. causing ink ejected from the ejection nozzle to land on the recording medium that is operated to move to
The second line head has a configuration similar to that of the first line head, is arranged apart from the first line head in the direction of relative movement of the recording medium, and is configured to eject the ink onto the recording medium. Let the ink ejected from the nozzle land,
A positional error of the image recording position of each head module of the first and second line heads with respect to a reference position in the direction of relative movement of the recording medium, and a tilt of each head module of the second line head with respect to a reference line printing a detection chart for detecting an inclination error by the first and second line heads ;
reading the printed detection chart to obtain a positional error with respect to an adjacent head module as a positional reference for each head module of the first line head; Acquiring a position error and a tilt error using the recording position by the head module of the corresponding first line head as a reference position,
correcting image recording timing of each head module of the first line head on the recording medium based on the obtained positional error of each head module of the first line head;
correcting the inclination of the recorded image to be recorded on the recording medium by each head module of the second line head based on the acquired inclination error of each head module of the second line head;
on the recording medium of each head module of the second line head based on the acquired position error of each head module of the second line head and correction of inclination of the recorded image of the second line head. A recording position correcting method characterized by correcting the image recording timing of a. 2. The recording position correcting method according to claim 1 , wherein the correction of the inclination of the recorded image corrects the recorded image to a shape that cancels out an inclination error of the head module. 3. The recording position correcting method according to claim 2 , wherein correction of the tilt of the recorded image is performed when the tilt error exceeds a predetermined allowable value. The inclination error of each head module of the second line head is an inclination error with respect to the ejection nozzle row of each head module of the first line head corresponding to each head module. The recording position correction method according to any one of claims 1 to 3 . The positional error of each head module of the first line head is the positional error of the other head module between adjacent head modules in the first line head with the position of one head module as a reference position. ,
The positional error of each head module of the second line head is a positional error with reference to the recording position after correction of the image recording timing by each head module of the first line head corresponding to each head module. 5. The recording position correcting method according to any one of claims 1 to 4 , characterized in that: The detection chart is
a first detection pattern indicating a positional error of one head module between adjacent head modules in the same line head, with the position of the other head module as a reference position;
a second detection indicating a position error of each head module of the second line head with respect to a recording position by each head module of the first line head corresponding to each head module of the second line head; 6. The recording position correcting method according to claim 5 , comprising at least a pattern and a pattern. 7. The recording position correction method according to claim 6 , wherein the first detection pattern and the second detection pattern have the same structure and are printed by two or more different head modules. 8. The method according to claim 6 , wherein the first detection pattern of the second line head and the second detection pattern are printed at corresponding positions in the direction of relative movement of the recording medium. Recording position correction method. The positional error of the first line head is the positional error of the adjacent head module with any one of the head modules of the first line head as the positional reference and the positional error of the adjacent head module with the adjacent head module as the positional reference. Furthermore, it includes both positional errors for adjacent head modules and positional errors for successively adjacent head modules with the most recent head module as a positional reference,
The positional error of each head module of the second line head is a positional error with reference to the recording position after correction of the image recording timing by each head module of the first line head corresponding to each head module. 5. The recording position correcting method according to any one of claims 1 to 4 , characterized in that: The positional error of the first line head is the positional error of the adjacent head module with any one of the head modules of the first line head as the positional reference and the positional error of the adjacent head module with the adjacent head module as the positional reference. Furthermore, it includes both positional errors for adjacent head modules and positional errors for successively adjacent head modules with the most recent head module as a positional reference,
The positional error of the second line head includes the positional error of any one head module of the second line head with respect to any one head module of the first line head, and the positional error of the head module of any one of the first line heads. The positional error of the adjacent head module with any one of the two line heads as the positional reference, and the positional error of the further adjacent head module with the adjacent head module as the positional reference. 5. The recording position correcting method according to any one of claims 1 to 4 , wherein the recording position correction method includes all positional errors of the head modules with respect to the most recent head module as a positional reference. 11. The recording position according to any one of claims 5 to 10 , wherein the re-correction of the image recording timing is performed based on a position error obtained by adding a variation amount of the recording position caused by correcting the inclination of the recorded image. correction method. 12. The recording position correction according to claim 1 , wherein the tilt error is calculated based on a difference between a position error near one end of each head module and a position error near the other end. Method. 13. The recording position correcting method according to claim 1 , wherein the first line head ejects ink having a lower lightness than the ink ejected by the second line head. 14. The recording position correcting method according to claim 13 , wherein black ink is ejected from said first line head. A plurality of short head modules in which a plurality of ejection nozzles are formed in a row are arranged in the direction of the ejection nozzle row, and the ejection onto the recording medium is relatively moved in a direction intersecting the ejection nozzle row. a first line head that lands ink ejected from nozzles;
It has the same configuration as the first line head, is arranged apart from the first line head in the direction of relative movement of the recording medium, and causes ink ejected from the ejection nozzles to land on the recording medium. a second line head;
By the first and second line heads, the position error of the image recording position of each head module of the first and second line heads with respect to the reference position in the relative movement direction of the recording medium, and the second line head. detection chart printing means for printing a detection chart for detecting a tilt error of the tilt of the head module of the head with respect to the reference line;
error acquisition means for reading the detection chart and acquiring position errors of the head modules of the first and second line heads and inclination errors of the head module of the second line head ;
recording timing correcting means for correcting the image recording timing of each of the head modules on the recording medium based on the position error;
image tilt correction means for correcting the tilt of the recording image recorded on the recording medium of each of the head modules based on the tilt error;
The recording timing correcting means corrects the image recording timing of the first line head based on the position error of each head module of the first line head, and the image tilt correcting means corrects the image recording timing based on the tilt error. correcting the inclination of the recorded image of the second line head, and adjusting the image recording timing of the second line head based on the position error of each head module of the second line head and the correction of the inclination of the recorded image; an image recording apparatus for correcting an image recording position on the recording medium by each head module of the first and second line heads . 16. The image recording apparatus according to claim 15 , wherein the recording position correction method according to any one of claims 2 to 14 is executed. A program that is executed in a computer device and controls an image recording device,
A recording position correction program for executing the recording position correction method according to any one of claims 1 to 14.

Images