JP2021041535A - Inkjet recording device, method for adjusting inkjet head of the same, adjustment support device for the inkjet head and adjustment support program for the inkjet head - Google Patents

Abstract

To provide an inkjet recording device that can record a high-quality image in recording an image using a plurality of inkjet heads configured by joining a plurality of head modules, a method for adjusting the inkjet heads, an adjustment support device for the inkjet heads and an adjustment support program for the inkjet heads.SOLUTION: A method for adjusting inkjet heads of an inkjet recording device includes: a step S1 of measuring modules Δx and effective recording widths of inkjet heads; a step S2 of determining the effective recording widths of the inkjet heads in a case that the modules Δx are set to zero; a step S3 of determining, for each inkjet head, a target value of the modules Δx required so that the effective recording widths of all inkjet heads are made to be identical; and a step S4 of adjusting the modules Δx of the inkjet heads so that the effective recording widths of all inkjet heads are made to be identical.SELECTED DRAWING: Figure 6

Description

The present invention relates to an inkjet recording device, an inkjet head adjustment method thereof, an inkjet head adjustment support device thereof, and an inkjet head adjustment support program thereof, and particularly includes a plurality of inkjet heads configured by connecting a plurality of head modules. The present invention relates to a single-pass type inkjet recording device, its inkjet head adjustment method, its inkjet head adjustment support device, and its inkjet head adjustment support program.

In a single-pass type inkjet recording device, an inkjet recording device including a plurality of inkjet heads of the same color is known (for example, Patent Documents 1-4 and the like). In such an inkjet recording device provided with a plurality of inkjet heads of the same color, since image recording can be shared by each inkjet head, there is an advantage that image recording can be speeded up. Further, even if a ejection defect occurs in a specific nozzle, it can be complemented by ejection from another inkjet head, so that there is an advantage that a high-quality image can be recorded.

Further, in an inkjet recording apparatus provided with a plurality of inkjet heads of the same color, there is also known a technique for improving the resolution by intentionally shifting the positions of the nozzles of the respective inkjet heads (for example, Patent Document 1 and the like).

Further, in an inkjet recording apparatus provided with an inkjet head of a plurality of colors, there is also known a technique of compensating for ejection defects caused by an inkjet head of a specific color by ejection from an inkjet head of another color (for example, Patent Documents). 5).

Japanese Unexamined Patent Publication No. 2006-6389 Japanese Unexamined Patent Publication No. 2005-238556 Japanese Unexamined Patent Publication No. 2010-149499 Japanese Unexamined Patent Publication No. 2008-23921 Japanese Unexamined Patent Publication No. 2003-136763

By the way, in an inkjet recording apparatus provided with a plurality of inkjet heads, in order to record a high-quality image, it is necessary to adjust the relative positional relationship between the respective inkjet heads with high accuracy. For example, in an inkjet recording device provided with a plurality of inkjet heads of the same color, when the ejection failure is supplemented by ejection from other inkjet heads, each inkjet is such that ink is dropleted at substantially the same position from each inkjet head. It is necessary to adjust the relative positional relationship between the heads. The same applies to the case where ejection defects are complemented by ejection from inkjet heads of other colors, and the relative positional relationship between each inkjet head is adjusted so that ink is dropped from each inkjet head at almost the same position. There is a need to. In addition, even when the position of the nozzles of each inkjet head is intentionally shifted to improve the resolution, the relative positional relationship between the respective inkjet heads is set so that the ink is dropped from each inkjet head to a predetermined position. Need to be adjusted.

However, it is difficult to adjust the position of each inkjet head so that the positions of the nozzles are aligned between the respective inkjet heads, and it takes a lot of time to adjust the position. In particular, in the case of an inkjet head configured by connecting a plurality of head modules, there is a problem that local deviation occurs because the characteristics (pitch between nozzles, ejection direction, etc.) are slightly different for each head module.

The present invention has been made in view of such circumstances, and is an inkjet recording device capable of recording a high-quality image when a plurality of inkjet heads configured by connecting a plurality of head modules are used to record an image. , The inkjet head adjustment method, the inkjet head adjustment support device, and the inkjet head adjustment support program.

The means for solving the above problems are as follows.

(1) A method for adjusting an inkjet head that adjusts the relative positional relationship between the inkjet heads in an inkjet recording apparatus provided with a plurality of line-type inkjet heads configured by connecting a plurality of head modules. In the inkjet head, it is a step of aligning the effective recording widths of all the inkjet heads to the same width by adjusting the spacing between the adjacent head modules, and the amount of deviation of the spacing between the adjacent head modules with respect to the reference spacing is defined as the module Δx. A method for adjusting an inkjet head of an inkjet recording apparatus, which comprises a step of equalizing the modules Δx in each of the inkjet heads and aligning the effective recording widths of all the inkjet heads to the same width.

According to this aspect, in each inkjet head, the distance between adjacent head modules is adjusted so that the modules Δx are equal, and the effective recording widths of all the inkjet heads are aligned to the same width. As a result, the deviation of the nozzle position that occurs between the respective inkjet heads can be kept within a certain range. That is, if the resolution is guaranteed to some extent for each head module, it is possible to suppress the deviation of the nozzle position that occurs between the respective inkjet heads by aligning the effective recording widths. This makes it possible to record high quality images.

The "same width" includes a range recognized as having substantially the same width. That is, in the range where the same effect is recognized, a range having almost the same width is included. In addition, "equal" includes a range that is considered to be substantially equal. That is, in the range where the same effect is recognized, a substantially equal range is included.

(2) A method for adjusting an inkjet head that adjusts the relative positional relationship between the inkjet heads in an inkjet recording device provided with a plurality of line-type inkjet heads configured by connecting a plurality of head modules. In the inkjet head, it is a step of aligning the effective recording widths of all the inkjet heads to the same width by adjusting the spacing between the adjacent head modules, and the amount of deviation of the spacing between the adjacent head modules with respect to the reference spacing is defined as the module Δx. A method for adjusting an inkjet head of an inkjet recording device, which comprises a step of setting the sum of the modules Δx of all the inkjet heads to 0 and aligning the effective recording widths of all the inkjet heads to the same width.

According to this aspect, the spacing between adjacent head modules is adjusted so that the sum of the modules Δx of all the inkjet heads becomes 0, so that the effective recording widths of all the inkjet heads are aligned to the same width. As a result, the deviation of the nozzle position that occurs between the respective inkjet heads can be kept within a certain range, and a high-quality image can be recorded.

The total sum of "0" includes a range that is substantially recognized as 0. That is, in the range in which the same effect is recognized, a range in which the value is almost 0 is included.

(3) Further, the method for adjusting the inkjet head of the above-mentioned inkjet recording device according to (2) above, wherein the modules Δx are equalized in each inkjet head and the effective recording widths of all the inkjet heads are made the same width.

According to this aspect, the distance between adjacent head modules is further adjusted so that the modules Δx are equal in each of the inkjet heads. That is, the spacing between adjacent head modules is adjusted so that the modules Δx are equal in each inkjet head and the sum of the modules Δx of all the inkjet heads is 0, so that all the inkjet heads are effective. The recording width is aligned to the same width. As a result, the deviation of the nozzle position that occurs between the respective inkjet heads can be kept within a certain range, and a high-quality image can be recorded.

(4) The method for adjusting the inkjet head of any one of the above-mentioned (1) to (3), wherein the reference interval is an interval in which the resolution is kept uniform at the joint of adjacent head modules.

According to this aspect, the interval at which the resolution is kept uniform at the joint of adjacent head modules is set as the reference interval. Therefore, the case where the module Δx is 0 is a case where adjacent head modules are attached at reference intervals, and a case where the resolution becomes uniform over the entire recording width.

The resolution can be represented by, for example, "npi". “Npi” means nozzle per inch and is a unit notation representing the number of nozzles per inch. One inch is 25.4 millimeters [mm]. Since the dots of one pixel can be recorded by one nozzle, "npi" can be understood by replacing it with "dpi". “Dpi” means dot per inch and is a unit notation representing the number of dots per inch.

(5) For each inkjet head, a step of measuring the module Δx and the effective recording width, a step of obtaining the effective recording width when the module Δx is set to 0, and a case where the module Δx is set to 0. From (1) above, further comprising a step of obtaining a target value of the module Δx for each inkjet head required for aligning the effective recording widths of all the inkjet heads to the same width based on the information of the effective recording width of the above. (3) A method for adjusting an inkjet head of an inkjet recording device according to any one of (3).

According to this aspect, the target value of adjustment necessary for aligning the effective recording widths of all the inkjet heads to the same width is obtained for each inkjet head. The adjustment target value is defined as the target value of the module Δx, and is obtained by the following procedure. First, the module Δx and the effective recording width are measured for each inkjet head. Next, for each of the inkjet heads, the effective recording width when the module Δx is set to 0 is obtained. Next, based on the information on the effective recording width when the module Δx is set to 0, the target value of the module Δx for each inkjet head required for aligning the effective recording widths of all the inkjet heads to the same width is obtained. For example, the target value of the module Δx required for each inkjet head to be aligned with the average value is obtained. Alternatively, the target value of the module Δx for each inkjet head required for aligning to a specific value is obtained. The specific value is, for example, a design value, an effective recording width of a specific inkjet head when the module Δx is set to 0, and the like.

(6) The average value of the effective recording width when the module Δx is set to 0 is obtained, and the target value of the module Δx for each inkjet head required to align the effective recording width of all the inkjet heads with the average value is obtained. (5) The method for adjusting the inkjet head of the inkjet recording device.

According to this aspect, the effective recording width of each inkjet head is aligned with the average value. In this case, the target value of the module Δx is obtained as a value necessary for aligning the effective recording width with the average value. Further, in this case, the sum of the modules Δx of all the inkjet heads is 0.

(7) The method for adjusting the inkjet head of the above-mentioned inkjet recording device (5), which obtains the target value of the module Δx for each inkjet head required to align the effective recording width of a specific inkjet head when the module Δx is set to 0. ..

According to this aspect, the effective recording width of each inkjet head is aligned with the effective recording width of a specific inkjet head when the module Δx is set to 0. It is aligned with the effective recording width of the inkjet head that ejects black ink droplets with high visibility regarding streaks, unevenness, and the like. This makes it possible to record a higher quality image.

(8) The method for adjusting the inkjet head of any one of the above-mentioned (5) to (7), which records a test chart with each inkjet head and measures the module Δx and the effective recording width.

According to this aspect, the module Δx and the effective recording width are measured by recording a predetermined test chart. That is, the module Δx and the effective recording width of each inkjet head are measured based on the recording result of the test chart.

(9) A step of detecting a region where the nozzle Δx does not fall within the specified range after the amount of deviation of the nozzle position between the inkjet heads is defined as the nozzle Δx and the effective recording widths of all the inkjet heads are aligned to the same width. The method for adjusting the inkjet head of any one of the above (1) to (8), further comprising a step of finely adjusting the position of the head module in a region where the nozzle Δx is not within the specified range. ..

According to this aspect, the position of the head module is finely adjusted after the effective recording widths of all the inkjet heads are aligned to the same width. That is, the position of the head module is finely adjusted so that the nozzle Δx falls within the specified range in all regions. As a result, the deviation of the nozzle position that occurs between the respective inkjet heads can be more accurately optimized.

(10) The method for adjusting an inkjet head of an inkjet recording device according to (9) above, wherein the specified range is within one pixel of a resolution composed of a single inkjet head.

According to this aspect, the position of the head module is adjusted so that the nozzle Δx is within one pixel of the resolution composed of a single inkjet head. As a result, it is possible to prevent the dots from being exchanged between the respective inkjet heads, and it is possible to record a high-quality image.

(11) The method for adjusting an inkjet head of an inkjet recording device according to (9) above, wherein the specified range is within 0.5 pixels of a resolution composed of a single inkjet head.

According to this aspect, the position of the head module is adjusted so that the nozzle Δx is within 0.5 pixels of the resolution composed of a single inkjet head. As a result, streak correction can be facilitated. That is, streak correction becomes possible without using large drops or the like.

(12) An inkjet recording device including a plurality of line-type inkjet heads configured by connecting a plurality of head modules, each of which has the same effective recording width and is adjacent to a reference interval. An inkjet recording device in which the modules Δx in each inkjet head are equal when the amount of deviation of the head module spacing is set to the module Δx.

According to this aspect, in each inkjet head, the distance between adjacent head modules is adjusted so that the modules Δx are equal, and the effective recording widths of all the inkjet heads are aligned to the same width. As a result, the deviation of the nozzle position that occurs between the respective inkjet heads can be kept within a certain range, and a high-quality image can be recorded.

(13) An inkjet recording device including a plurality of line-type inkjet heads configured by connecting a plurality of head modules, wherein the plurality of inkjet heads each have the same effective recording width and with respect to a reference interval. An inkjet recording device in which the total sum of modules Δx of all inkjet heads is 0, where the amount of deviation between adjacent head modules is module Δx.

According to this aspect, the spacing between adjacent head modules is adjusted so that the sum of the modules Δx of all the inkjet heads becomes 0, so that the effective recording widths of all the inkjet heads are aligned to the same width. As a result, the deviation of the nozzle position that occurs between the respective inkjet heads can be kept within a certain range, and a high-quality image can be recorded.

(14) Further, the above-mentioned inkjet recording apparatus according to (13), wherein the modules Δx in each of the inkjet heads are equal.

According to this aspect, the distance between adjacent head modules is further adjusted so that the modules Δx are equal in each of the inkjet heads. That is, the spacing between adjacent head modules is adjusted so that the modules Δx are equal in each inkjet head and the sum of the modules Δx of all the inkjet heads is 0, so that all the inkjet heads are effective. The recording width is aligned to the same width. As a result, the deviation of the nozzle position that occurs between the respective inkjet heads can be kept within a certain range, and thus a high-quality image can be recorded.

(15) The inkjet recording apparatus according to any one of (12) to (14) above, wherein the reference interval is an interval at which the resolution is kept uniform at the joint of adjacent head modules.

According to this aspect, the interval at which the resolution is kept uniform at the joint of adjacent head modules is set as the reference interval.

(16) A control unit for controlling the drive of the inkjet head is further provided, and the control unit makes the defective nozzles non-ejective when a defective nozzle occurs in one inkjet head, and emits the defective nozzle from the nozzle of the other one inkjet head. The inkjet recording device according to any one of (12) to (15) above, which is complemented by ejection.

According to this aspect, when a defective nozzle is generated in one inkjet head, the defective nozzle is made non-ejective and complemented by ejection from the nozzle of the other one inkjet head.

(17) An inkjet head adjustment support device that supports adjustment of a relative positional relationship between inkjet heads in an inkjet recording device provided with a plurality of line-type inkjet heads configured by connecting a plurality of head modules. , When the amount of deviation between adjacent head modules with respect to the reference interval is set to module Δx, the information acquisition unit that acquires the information of the module Δx and the information of the effective recording width of each inkjet head, and the respective inkjet heads. Based on the information of the effective recording width calculation unit that calculates the effective recording width when the module Δx is 0 and the effective recording width when the module Δx is 0, the effective recording width of all the inkjet heads is set to the same width. Inkjet of an inkjet recording device including a target value calculation unit that calculates a target value of a module Δx for each inkjet head required for alignment and an output unit that outputs a calculated target value of a module Δx for each inkjet head. Head adjustment support device.

According to this aspect, the target value of adjustment necessary for aligning the effective recording widths of all the inkjet heads to the same width is obtained for each inkjet head and output. The adjustment target value is defined as the target value of the module Δx, and is obtained by the following procedure. First, the information on the module Δx and the information on the effective recording width are acquired for each of the inkjet heads. Next, for each of the inkjet heads, the effective recording width when the module Δx is set to 0 is obtained. Next, based on the information on the effective recording width when the module Δx is set to 0, the target value of the module Δx for each inkjet head required for aligning the effective recording widths of all the inkjet heads to the same width is obtained. The target value of the module Δx for each obtained inkjet head is output.

(18) An inkjet head adjustment support program that supports adjustment of relative positional relationships between inkjet heads in an inkjet recording apparatus provided with a plurality of line-type inkjet heads configured by connecting a plurality of head modules. , When the amount of deviation between adjacent head modules with respect to the reference interval is set to module Δx, the function of acquiring the information of the module Δx and the information of the effective recording width of each inkjet head and the module Δx for each inkjet head. The inkjet required to align the effective recording widths of all the inkjet heads to the same width based on the function of calculating the effective recording width when is set to 0 and the information of the effective recording width when the module Δx is set to 0. An inkjet head adjustment support program for an inkjet recording device that realizes a function of calculating the target value of the module Δx for each head and a function of outputting the calculated target value of the module Δx for each inkjet head on a computer.

According to this aspect, the target value of adjustment necessary for aligning the effective recording widths of all the inkjet heads to the same width is obtained for each inkjet head and output. The adjustment target value is defined as the target value of the module Δx, and is obtained by the following procedure. First, the information on the module Δx and the information on the effective recording width are acquired for each of the inkjet heads. Next, for each of the inkjet heads, the effective recording width when the module Δx is set to 0 is obtained. Next, based on the information on the effective recording width when the module Δx is set to 0, the target value of the module Δx for each inkjet head required for aligning the effective recording widths of all the inkjet heads to the same width is obtained. The target value of the module Δx for each obtained inkjet head is output.

According to the present invention, a high-quality image can be recorded when a plurality of inkjet heads configured by connecting a plurality of head modules are used to record an image.

A side view showing a schematic configuration of an embodiment of an inkjet recording device. Top view showing schematic structure of one Embodiment of an inkjet recording apparatus Bottom view showing a schematic configuration of an embodiment of the first inkjet head The figure which shows the schematic structure of the nozzle surface of a head module. Block diagram showing a schematic configuration of a control system of an inkjet recording device Flowchart showing the procedure for adjusting the relative positional relationship between each inkjet head The figure which showed typically the adjustment process of each inkjet head Table showing the transition of module Δx The figure which schematically showed the adjustment process of three inkjet heads Table showing the transition of module Δx Table showing the transition of module Δx The figure which shows the comparison of the line recorded by two head modules. The figure which shows the comparison of the line recorded by two head modules. The figure which shows an example of the test chart which measures a nozzle Δx Enlarged view of a part of FIG. 14 (area surrounded by a frame shown by a broken line) The figure which shows the measurement example when the effective recording width is measured as a relative value. Block diagram showing an embodiment of an inkjet head adjustment support device

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Inkjet recording device]
1 and 2 are side views and plan views showing a schematic configuration of an embodiment of an inkjet recording device to which the present invention is applied, respectively.

The inkjet recording device 1 is a line printer that records (prints) a desired image on a sheet of paper in a single pass, and is used on a paper transport unit 10 that conveys the paper P and a paper P that is conveyed by the paper transport unit 10. An inkjet recording unit 20 that records an image by an inkjet method, an image reading unit 30 that reads an image recorded on the paper P, a paper feeding unit 40 that supplies the paper P to the paper transport unit 10, and a paper P after image recording. Is provided with a paper ejection unit 50 for ejecting paper.

《Paper carrier》
The paper transport unit 10 transports the paper P to be recorded along a fixed transport path. In the inkjet recording device 1 of the present embodiment, the paper P is conveyed by a belt. That is, the paper P is adsorbed on the surface of the traveling belt 11 and conveyed. The belt 11 is composed of an endless belt, and is wound around a driving roller 12 and a driven roller 13. A belt drive motor 14 is connected to the drive roller 12. The belt 11 travels by rotating the drive roller 12 by the belt drive motor 14. The paper P is attracted to the belt 11 by utilizing the air pressure (negative pressure). The belt 11 is provided with a large number of suction holes, and the paper P is attracted to the surface of the belt 11 by suction from the inside. Inside the belt 11, a suction unit 16 for sucking the belt 11 from the inside is provided.

<< Inkjet recording unit >>
The inkjet recording unit 20 records an image on the paper P conveyed by the belt 11 by an inkjet method. That is, droplets of ink are ejected toward the paper P, the coloring material is adhered to the paper P, and a desired image is recorded.

The inkjet recording unit 20 is provided with two inkjet heads 21A and 21B that eject ink droplets of the same color. The two inkjet heads 21A and 21B are composed of line heads (line-type inkjet heads) corresponding to the paper width. The two inkjet heads 21A and 21B are arranged at regular intervals on the transport path of the paper P by the belt 11. Further, the two inkjet heads 21A and 21B are arranged orthogonal to the conveying direction (Y direction) of the paper P by the belt 11. Since each of the two inkjet heads 21A and 21B is arranged orthogonal to the conveying direction (Y direction) of the paper P, the two inkjet heads 21A and 21B are arranged in parallel with each other. Hereinafter, if necessary, the inkjet head 21A located on the upstream side in the transport direction of the paper P will be referred to as a first inkjet head 21A, and the inkjet head 21B located on the downstream side will be referred to as a second inkjet head 21B to distinguish between the two.

The two inkjet heads 21A and 21B are configured by connecting a plurality of head modules, respectively. This point will be described later.

In the paper P conveyed by the belt 11, ink droplets are ejected from at least one of the first inkjet head 21A and the second inkjet head 21B in the conveying process, and an image is recorded on the surface of the paper P.

<< Image reader >>
The image reading unit 30 reads the image recorded on the paper P. The image reading unit 30 is provided with an image reading device 31. The image reading device 31 is composed of a line scanner and reads an image from the paper P conveyed by the belt 11.

<< Paper feed section >>
The paper feeding unit 40 includes a known paper feeding device, separates the paper P stacked on the tray one by one, and supplies the paper P to the paper conveying unit 10.

《Paper ejection part》
The paper ejection unit 50 receives the paper P on which the image is recorded from the paper transport unit 10 and collects the paper P on the tray.

[Inkjet head]
As described above, the inkjet heads 21A and 21B are configured by connecting a plurality of head modules. That is, a line head is formed by connecting a plurality of head modules.

Since the configurations of the two inkjet heads 21A and 21B are the same, the configuration of the first inkjet head 21A will be described here.

FIG. 3 is a bottom view (a view seen from the nozzle surface side) showing a schematic configuration of an embodiment of the first inkjet head.

As shown in FIG. 3, the first inkjet head 21A is configured by connecting a plurality of head modules 22A having the same structure in a row.

Each head module 22A is attached to the base 23A and integrated. The base 23A has a bar shape and has a number of head module mounting portions (not shown) corresponding to the number of head modules 22A installed.

The head module mounting portions are provided at regular intervals along the longitudinal direction of the base 23A (= longitudinal direction of the inkjet head 21A: the X direction in the drawing). The head module 22A is detachably and position-adjustably attached to the head module mounting portion. That is, the head module mounting portion has a holding mechanism for holding the head module 22A detachably, and also has a position adjusting function for finely adjusting the position of the held head module 22A. As a result, the head module 22A can be replaced individually, and the position of the attached head module 22A can be adjusted individually.

The position adjustment mechanism may be capable of adjusting the position of the head module 22A in the arrangement direction and the position of the base 23A in the longitudinal direction (X direction). Thereby, the distance between the adjacent head modules 22A can be adjusted.

FIG. 4 is a diagram showing a schematic configuration of a nozzle surface of the head module.

As shown in FIG. 4, each head module 22A has a nozzle 25A on the nozzle surface 24A. By attaching each head module 22A to the base 23A, the nozzle surface 24A is located on the same surface.

The nozzle 25A is arranged to achieve the desired resolution. In the present embodiment, as shown in FIG. 4, the nozzles 25A are arranged in a matrix, and a desired resolution (for example, 1200 dpi) is realized.

[Control system of inkjet recording device]
FIG. 5 is a block diagram showing a schematic configuration of a control system of an inkjet recording device.

The entire operation of the inkjet recording device 1 is controlled by the control unit 100. The control unit 100 is composed of a computer and executes a predetermined control program to control the operation of each unit. That is, the paper feeding unit 40 is controlled so that the paper P is fed one by one, and the paper transporting unit 10 is controlled so that the fed paper P is conveyed at a constant speed. Further, the inkjet recording unit 20 is controlled so that a desired image is recorded on the conveyed paper P, and the image reading unit 30 is controlled so as to read the recorded image. Further, the paper ejection unit 50 is controlled so that the recorded paper P is accumulated at a predetermined position.

The control unit 100 includes an operation unit 101 for operating the inkjet recording device 1, a display unit 102 for displaying various information, a communication unit 103 for communicating with an external device, a program required for control, various data, and the like. A storage unit 104 or the like for storing the data is connected.

The image data to be recorded is acquired from an external device via the communication unit 103. The control unit 100 generates dot on / off data (dot arrangement data), which is recording data, from the acquired image data. When recording an image, the driving of the inkjet heads 21A and 21B is controlled based on the generated recording data.

As described above, the inkjet recording device 1 of the present embodiment includes two inkjet heads 21A and 21B that eject ink droplets of the same color. Therefore, when recording an image, the two inkjet heads 21A and 21B can be used at the same time or alternately. Further, when a ejection defect occurs in one of the inkjet heads, it can be supplemented by ejection from the other inkjet head. That is, the nozzle in which the ejection defect has occurred (defective nozzle) is made non-ejection, and the ejection from the corresponding nozzle of the other inkjet head is complemented.

[Inverter head adjustment method]
When the inkjet heads are multiplexed as in the inkjet recording device 1 of the present embodiment, it is necessary to adjust the relative positional relationship between the respective inkjet heads with high accuracy. That is, it is necessary to keep the amount of deviation of the nozzle position that occurs between the respective inkjet heads within a certain range.

Here, the amount of deviation of the nozzle position that occurs between the respective inkjet heads is the amount of deviation that occurs between the corresponding nozzles of each inkjet head in the X direction. Let this deviation amount be the nozzle Δx. The corresponding nozzle is, for example, a nozzle provided with the same number when the nozzles provided in each inkjet head are numbered from one end along the X direction.

By setting the nozzle ΔX to 0 over the entire recording width, ink can be dropped from each inkjet head at the same position. That is, when ink droplets are ejected from the corresponding nozzles, the ink droplets can be ejected at the same position in the X direction.

However, in a line-type inkjet head configured by connecting a plurality of head modules, it is difficult to set the nozzle ΔX to 0 over the entire recording width. Therefore, in the inkjet recording device 1 of the present embodiment, the relative positional relationship between the respective inkjet heads is adjusted by the following method so that the nozzle ΔX is within a certain range between the respective inkjet heads.

<< Conventional adjustment method >>
First, for comparison, a conventional adjustment method will be described.

Conventionally, the resolution is individually adjusted for each inkjet head, and then the relative positions of the individual inkjet heads are adjusted. The resolution is adjusted by adjusting the distance between adjacent head modules. At that time, the resolution is adjusted to be uniform over the entire recording width.

However, since the characteristics (pitch between nozzles, discharge direction, etc.) are slightly different for each head module, it is difficult to keep the nozzle Δx within a certain range by the conventional method.

<< Adjustment method of this embodiment >>
If the resolution is guaranteed to some extent for each head module, the nozzle Δx can be kept within a certain range between the respective inkjet heads by aligning the effective recording widths of the respective inkjet heads to the same width.

Therefore, in the inkjet recording device 1 of the present embodiment, the effective recording width of each inkjet head is adjusted to the same width.

The effective recording width means the maximum width that can be recorded by the inkjet head. The effective recording width is synonymous with the maximum recording width.

The effective recording width is adjusted by adjusting the module Δx of each inkjet head. The module Δx is the amount of deviation of the spacing between adjacent head modules with respect to the reference spacing. Therefore, the effective recording width of each inkjet head is adjusted by adjusting the distance between adjacent head modules.

Here, the reference interval is an interval at which the resolution is kept uniform at the joints of adjacent head modules. Therefore, when the module Δx is 0 among all the head modules, the resolution of the inkjet head is kept uniform over the entire recording width.

In the inkjet recording device 1 of the present embodiment, the modules Δx are adjusted to be uniform in each inkjet head so that the effective recording width of each inkjet head is made the same width. Further, in the inkjet recording device 1 of the present embodiment, the total of the modules Δx of all the inkjet heads is adjusted to be 0, and the effective recording width of each inkjet head is made the same width.

The "same width" here includes a range recognized as having substantially the same width. That is, in the range where the same effect is recognized, a range having almost the same width is included. In addition, "equal" includes a range that is considered to be substantially equal. That is, in the range where the same effect is recognized, a substantially equal range is included. Further, the total sum of "0" includes a range recognized as substantially 0. That is, in the range where the same effect is recognized, a range of almost 0 is included.

<< Specific adjustment method >>
FIG. 6 is a flowchart showing a procedure for adjusting the relative positional relationship between the inkjet heads.

First, the module Δx and the effective recording width of each inkjet head are measured (step S1). The module Δx and the effective recording width of each inkjet head are measured by recording a predetermined test chart (test pattern). That is, a predetermined test chart is recorded, the recording result is read by the image reading unit 30, the image of the read test chart is analyzed, and the module Δx and the effective recording width of each inkjet head are measured.

Next, the effective recording width of each inkjet head when the module Δx between all the head modules is set to 0 is calculated (step S2).

Next, the target value of the module Δx of each inkjet head required to align the effective recording width of each inkjet head to the same width is calculated (step S3). The target value of the module Δx of each inkjet head is calculated based on the information of the effective recording width of each inkjet head when the module Δx is set to 0. Here, the target value of the module Δx of each inkjet head is calculated by the following procedure.

First, the average value of the effective recording widths of each inkjet head when the module Δx is set to 0 is obtained. The obtained average value is the effective recording width of each inkjet head to be aligned this time. In each inkjet head, the module Δx is evenly allocated so that the effective recording width becomes equal to the obtained average value, and the target value of the module Δx is calculated. When the target value of the module Δx is calculated in this way, the sum of the target values of the module Δx of all the inkjet heads becomes 0.

Next, the module Δx of each inkjet head is adjusted based on the obtained target value, and the effective recording width of each inkjet head is corrected (step S4). That is, the distance between adjacent head modules is adjusted for each inkjet head so that the module Δx becomes equal to the target value obtained among all the head modules. As a result, the effective recording width of each inkjet head is aligned to the same width.

After that, the position of each inkjet head is adjusted so that the ink is dropped from the corresponding nozzles at the same position. For example, it is adjusted so that the positions of both ends are aligned. Alternatively, it is adjusted so that the positions of the centers are aligned.

In the above series of steps, the adjustment process of the relative positional relationship between the inkjet heads is completed. As a result, the deviation of the nozzle position that occurs between the respective inkjet heads can be kept within a certain range.

According to the adjustment method of the present embodiment, the module Δx and the effective recording width of each inkjet head are measured and adjusted so that the effective recording widths are uniform, so that the adjustment can be easily performed.

<< Adjustment example >>
An example of adjustment is shown below. In the following, for the sake of simplicity, a case where the two inkjet heads 21A and 21B are each composed of three head modules will be described as an example.

FIG. 7 is a diagram schematically showing the process of adjusting each inkjet head. In the figure, reference numeral 7A indicates an initial state, reference numeral 7B indicates a state in which the module Δx is set to 0, and reference numeral 7C indicates a state in which adjustment is completed.

In the figure, reference numerals 22A (1), 22A (2) and 22A (3) indicate the first, second and third head modules constituting the first inkjet head 21A, respectively. Further, reference numerals 22B (1), 22B (2) and 22B (3) indicate the first, second and third head modules constituting the second inkjet head 21B, respectively. The alternate long and short dash line indicates the center position of each head module.

Further, in this example, the head modules 22A (1), 22A (2), and 22A (3) constituting the first inkjet head 21A are the head modules 22B (1), 22B (2) constituting the second inkjet head 21B. ), 22B (3) and shorter.

FIG. 8 is a table showing the transition of the module Δx.

In the figure, module Δx1 (1-2) indicates a module Δx between the first surface head module 22A (1) and the second head module 22A (2) in the first inkjet head 21A. Module Δx1 (2-3) indicates a module Δx between the head module 22A (2) on the second surface of the first inkjet head 21A and the third head module 22A (3). Further, the module Δx2 (1-2) indicates a module Δx between the head module 22B (1) on the first surface and the second head module 22B (2) in the second inkjet head 21B, and the module Δx2. (2-3) shows the module Δx between the head module 22B (2) on the second surface of the second inkjet head 21B and the third head module 22B (3).

<Step S1>
First, the module Δx and the effective recording width of each inkjet head are measured.

FIG. 8 shows a case where the module Δx1 (1-2) is “-1” and the module Δx1 (2-3) is “+4” with respect to the first inkjet head 21A as a result of the measurement. Further, regarding the second inkjet head 21B, the case where the module Δx2 (1-2) is “+1” and the module Δx2 (2-3) is “+3” is shown.

Further, the case where the effective recording width of the first inkjet head 21A is "design value +10" and the effective recording width of the second inkjet head 21B is "design value -1" is shown.

<Step S2>
Next, the effective recording width of each inkjet head when the module Δx is set to 0 is calculated.

FIG. 8 shows a case where the effective recording width is “design value +7” as a result of setting the module Δx1 (1-2) and the module Δx1 (2-3) to 0 with respect to the first inkjet head 21A. Further, regarding the second inkjet head 21B, the case where the effective recording width is “design value −5” as a result of setting the module Δx2 (1-2) and the module Δx2 (2-3) to 0 is shown.

FIG. 7B of FIG. 7 shows a state in which the module Δx of each inkjet head is set to 0. Note that 7B in FIG. 7 is shown for facilitating the understanding of the invention, and it is not necessary to actually set the module Δx of each inkjet head to 0. That is, the effective recording width of each inkjet head when the module Δx is set to 0 can be obtained by calculation.

<Step S3>
Next, the target value of the module Δx of each inkjet head required for aligning the effective recording width of each inkjet head to the same width is calculated.

First, the average value of the effective recording width of each inkjet head when the module Δx is set to 0 is obtained among all the head modules. When all the modules Δx are set to 0, the effective recording width of the first inkjet head 21A is “design value +7”. Further, when all the modules Δx are set to 0, the effective recording width of the second inkjet head 21B is “design value −5”. Therefore, the average value is "design value + 1". This "design value + 1" is the effective recording width to be aligned.

When all the modules Δx are set to 0, the effective recording width of the first inkjet head 21A is “design value +7”. Therefore, the total sum of the modules Δx1 for setting the effective recording width of the first inkjet head 21A to “design value +1” is “-6”. When "-6" is evenly distributed among the head modules, it is "-3". Therefore, the target value of the module Δx1 in the first inkjet head 21A is “-3”.

On the other hand, when all the modules Δx are set to 0, the effective recording width of the second inkjet head 21B is “design value −5”. Therefore, the total sum of the modules Δx for setting the effective recording width of the second inkjet head 21B to “design value +1” is “+6”. When "+6" is evenly distributed among the head modules, it is "+3". Therefore, the target value of the module Δx in the second inkjet head 21B is “+3”.

<Step S4>
Next, the module Δx of each inkjet head is adjusted so as to obtain the obtained target value, and the effective recording width of each inkjet head is corrected.

As a result, in FIG. 7, as shown by 7C, the effective recording widths of the respective inkjet heads are aligned to the same width. After that, the mutual positions are adjusted so that the ink is dropped from the corresponding nozzles at the same position. For example, the position is adjusted so that the positions of both ends are aligned.

In this example, each inkjet head is composed of three head modules, but it can be adjusted by the same method when it is further composed of a plurality of head modules.

[Modification example]
<< Adjustment example when multiple inkjet heads are provided >>
The present invention can also be applied to an inkjet recording device provided with a plurality of inkjet heads. An example of adjustment when three inkjet heads are provided is shown below.

Similarly to the above, in order to simplify the explanation, here, a case where each inkjet head is composed of three head modules will be described as an example.

FIG. 9 is a diagram schematically showing the process of adjusting the three inkjet heads.

The three inkjet heads are the first inkjet head 21A, the second inkjet head 21B, and the third inkjet head 21C.

In FIG. 9, reference numeral 9A indicates an initial state, reference numeral 9B indicates a state in which the module Δx is set to 0, and reference numeral 9C indicates a state in which the adjustment is completed.

Further, among the head modules constituting each inkjet head, the head module shown by the diagonal line indicates that the head module has a long length. That is, this example shows a case where each inkjet head is configured by using two types of head modules having different lengths. The alternate long and short dash line indicates the center position of each head module.

FIG. 10 is a table showing the transition of the module Δx.

In the figure, the module Δx1 (1-2) shows the module Δx of the first surface and the second head module of the first inkjet head 21A, and the module Δx1 (2-3) is the first inkjet head 21A. The module Δx of the second surface and the third head module of the above is shown. Further, the module Δx2 (1-2) indicates the module Δx of the first surface of the second inkjet head 21B and the second head module, and the module Δx2 (2-3) is the first surface of the second inkjet head 21B. The module Δx of the second surface and the third head module is shown. Further, the module Δx3 (1-2) indicates the module Δx of the first surface and the second head module of the third inkjet head 21C, and the module Δx3 (2-3) is the third inkjet head 21C. The module Δx of the second surface and the third head module is shown.

<Step S1>
First, the module Δx and the effective recording width of each inkjet head are measured.

FIG. 10 shows a case where the module Δx1 (1-2) is “-1” and the module Δx1 (2-3) is “+4” with respect to the first inkjet head 21A as a result of the measurement. Further, regarding the second inkjet head 21B, the case where the module Δx2 (1-2) is “+1” and the module Δx2 (2-3) is “+3” is shown. Further, regarding the third inkjet head 21C, the case where the module Δx3 (1-2) is “+3” and the module Δx3 (2-3) is “0” is shown.

Further, the effective recording width of the first inkjet head 21A is "design value +10", the effective recording width of the second inkjet head 21B is "design value -1", and the effective recording width of the third inkjet head 21C is "design value +6". It shows the case where it was.

<Step S2>
Next, the effective recording width of each inkjet head when the module Δx is set to 0 is calculated among all the head modules.

FIG. 10 shows a case where the effective recording width is “design value +7” as a result of setting the module Δx1 (1-2) and the module Δx1 (2-3) to 0 with respect to the first inkjet head 21A. Further, regarding the second inkjet head 21B, the case where the effective recording width is “design value −5” as a result of setting the module Δx2 (1-2) and the module Δx2 (2-3) to 0 is shown. Further, regarding the third inkjet head 21C, the case where the effective recording width becomes "design value +3" as a result of setting the module Δx3 (1-2) and the module Δx3 (2-3) to 0 is shown.

<Step S3>
Next, the target value of the module Δx of each inkjet head required for aligning the effective recording width of each inkjet head to the same width is calculated.

First, the average value of the effective recording width of each inkjet head when the module Δx is set to 0 is obtained among all the head modules. When all modules Δx are set to 0, the effective recording width of the first inkjet head 21A is “design value +7”, and when all modules Δx are set to 0, the effective recording width of the second inkjet head 21B is “design value −”. 5 ”, the effective recording width of the third inkjet head 21C when all the modules Δx are set to 0 is“ design value +6 ”. Therefore, the average value is "design value + 1.67". This "design value + 1.67" is the effective recording width to be aligned.

When all the modules Δx are set to 0, the effective recording width of the first inkjet head 21A is “design value +7”. Therefore, the total sum of the modules Δx1 for setting the effective recording width of the first inkjet head 21A to “design value + 1.67” is “−5.33”. When "-5.33" is evenly distributed among the head modules, it is "-2.67". Therefore, the target value of the module Δx1 in the first inkjet head 21A is “-2.67”.

On the other hand, when all the modules Δx are set to 0, the effective recording width of the second inkjet head 21B is “design value −5”. Therefore, the total sum of the modules Δx for setting the effective recording width of the second inkjet head 21B to “design value +1.67” is “+6.67”. When "+6.67" is evenly distributed among the head modules, it is "+3.34". Therefore, the target value of the module Δx in the second inkjet head 21B is “+3.34”.

Further, when all the modules Δx are set to 0, the effective recording width of the third inkjet head 21C is “design value +3”. Therefore, the total sum of the modules Δx for setting the effective recording width of the third inkjet head 21C to “design value + 1.67” is “−1.33”. When "-1.33" is evenly distributed among the head modules, it is "-0.67". Therefore, the target value of the module Δx in the third inkjet head 21C is “−0.67”.

<Step S4>
Next, the module Δx of each inkjet head is adjusted so as to obtain the obtained target value, and the effective recording width of each inkjet head is corrected.

As a result, in FIG. 9, as shown by 9C, the effective recording widths of the respective inkjet heads are aligned to the same width. After that, the mutual positions are adjusted so that the ink is dropped from the corresponding nozzles at the same position. For example, the position is adjusted so that the positions of both ends are aligned.

Further, when a plurality of inkjet heads are provided, the effective recording width of each inkjet head can be made uniform by the same method. In this case, each inkjet head may be an inkjet head that ejects ink of the same type or color, or may be an inkjet head that ejects ink of a different type or color. Therefore, an inkjet head that ejects inks of all different colors (for example, an inkjet head that ejects cyan (Cyan, C), magenta (Magenta, M), yellow (Yellow, Y), and black (Black, Bk) ink). It may be. Further, a plurality of specific colors may be provided.

<< Other examples of effective recording width to be aligned >>
In the above embodiment, the case of aligning with the average value of the effective recording widths of the respective inkjet heads when the module Δx is set to 0 has been described as an example, but the effective recording width to be aligned is not limited to this. It may match a predetermined specific value. For example, it may match the design value.

Further, the effective recording widths of the other inkjet heads may be aligned with reference to one of the plurality of inkjet heads. In this case, it is preferable that the reference inkjet head is adjusted so that the module Δx becomes 0 among all the head modules. That is, it is preferable to adjust so that the resolution is kept constant over the entire recording width.

An example of adjustment of this aspect is shown below. Here, in order to simplify the explanation, a case where three inkjet heads are provided will be described as an example. Further, a case where each inkjet head is composed of three head modules will be described as an example.

The three inkjet heads are referred to as a first inkjet head, a second inkjet head, and a third inkjet head, respectively. A case will be described in which the effective recording widths of the second and third inkjet heads are aligned with the effective recording widths of the first inkjet head with the first inkjet head as a reference.

FIG. 11 is a table showing the transition of the module Δx.

In the figure, the module Δx1 (1-2) shows the module Δx of the first surface of the first inkjet head and the second head module, and the module Δx1 (2-3) is the first of the first inkjet heads. The module Δx of the second surface and the third head module is shown. Further, the module Δx2 (1-2) indicates the first surface of the second inkjet head and the module Δx of the second head module, and the module Δx2 (2-3) is the second inkjet head of the second inkjet head. The surface and the module Δx of the third head module are shown. Further, the module Δx3 (1-2) indicates the first surface of the third inkjet head and the module Δx of the second head module, and the module Δx3 (2-3) is the second surface of the third inkjet head. The surface and the module Δx of the third head module are shown.

<Step S1>
First, the module Δx and the effective recording width of each inkjet head are measured.

FIG. 11 shows a case where the module Δx1 (1-2) is “-1” and the module Δx1 (2-3) is “+4” as a result of the measurement. Further, regarding the second inkjet head, the case where the module Δx2 (1-2) is “+1” and the module Δx2 (2-3) is “+3” is shown. Further, regarding the third inkjet head, the case where the module Δx3 (1-2) is “+3” and the module Δx3 (2-3) is “0” is shown.

Further, the effective recording width of the first inkjet head was "design value +10", the effective recording width of the second inkjet head was "design value -1", and the effective recording width of the third inkjet head was "design value +6". Shows the case.

<Step S2>
Next, the effective recording width of each inkjet head when the module Δx is set to 0 is calculated among all the head modules.

FIG. 11 shows a case where the effective recording width is “design value +7” as a result of setting the module Δx1 (1-2) and the module Δx1 (2-3) to 0 with respect to the first inkjet head. Further, regarding the second inkjet head, the case where the effective recording width is “design value −5” as a result of setting the module Δx2 (1-2) and the module Δx2 (2-3) to 0 is shown. Further, regarding the third inkjet head, the case where the effective recording width becomes "design value +3" as a result of setting the module Δx3 (1-2) and the module Δx3 (2-3) to 0 is shown.

<Step S3>
Next, the target value of the module Δx of each inkjet head required for aligning the effective recording width of each inkjet head to the same width is calculated.

In this example, since the effective recording width of the first inkjet head is aligned, the target value of the module Δx of the first inkjet head is 0.

Since the second inkjet head and the third inkjet head are aligned with the effective recording width of the first inkjet head, the target value is calculated from the difference from the effective recording width of the first inkjet head.

Regarding the second inkjet head, the effective recording width when all the modules Δx are set to 0 is “design value −5”. On the other hand, the effective recording width of the first inkjet head is "design value +7". Therefore, the sum of the modules Δx for matching the effective recording width of the second inkjet head with the effective recording width of the first inkjet head is “+12”. When "+12" is evenly distributed among the head modules, it is "+6". Therefore, the target value of the module Δx in the second inkjet head 21B is “+6”.

Further, when all the modules Δx are set to 0, the effective recording width of the third inkjet head is “design value +3”. Therefore, the sum of the modules Δx for matching the effective recording width of the third inkjet head with the effective recording width of the first inkjet head is “+4”. When "+4" is evenly distributed among the head modules, it is "+2". Therefore, the target value of the module Δx in the third inkjet head is “+3”.

<Step S4>
Next, the module Δx of each inkjet head is adjusted so as to obtain the obtained target value, and the effective recording width of each inkjet head is corrected.

As a result, the effective recording width of each inkjet head is aligned to the same width. That is, it is aligned with the effective recording width of the first inkjet head when the module Δx is set to 0.

As described above, it is also effective to align the effective recording width with the specific inkjet head as a reference. For example, when a plurality of inkjet heads that eject inks of different colors are provided, it is conceivable that the effective recording widths are aligned with reference to the inkjet heads of a specific color. For example, it is conceivable that the effective recording width is made uniform with reference to an inkjet head that ejects ink having high visibility for streaks, unevenness, and the like (for example, black ink).

Further, when a plurality of inkjet heads for ejecting inks having different colors are provided, it is also effective to arrange the effective recording widths with reference to the inkjet heads constituting the important color mixing. In this case, the effective recording width of each inkjet head is made uniform by the following procedure. First, the average value of the effective recording widths (the average value when the module Δx is set to 0) of the inkjet heads constituting the important color mixing is obtained. Set the obtained average value to the effective recording width to be aligned, and adjust the effective recording width of each inkjet head.

<< Other examples of arrangement of each inkjet head after aligning the effective recording width >>
In the above embodiment, after aligning the effective recording widths of the respective inkjet heads to the same width, the positions of the respective inkjet heads are adjusted so that the ink is dropped from the corresponding nozzles to the same positions. By adjusting in this way, when a ejection defect occurs in one inkjet head, it can be complemented by ejection from another inkjet head.

The mode of arrangement of the respective inkjet heads after aligning the effective recording width is not limited to this. It is preferable to arrange it according to the purpose or application. For example, in order to increase the resolution, the arrangement may be intentionally staggered. Similarly, in order to secure the color gamut, the arrangement may be intentionally staggered. Further, the positions of the joints of the head modules may be staggered from each other so that they do not overlap with each other. Since the joints of the head modules cause unevenness, streaks, etc., the occurrence of unevenness, streaks, etc. can be effectively prevented by arranging the inkjet heads so as to be staggered from each other.

<< Other methods for aligning the effective print width of each inkjet head to the same width >>
In the above embodiment, the modules Δx are evenly distributed in each of the inkjet heads so that the effective print widths of the respective inkjet heads are aligned with the same width. However, a method of aligning the effective print widths of the respective inkjet heads with the same width is used. , Not limited to this. For example, the modules Δx of each inkjet head may be adjusted so that the sum of the modules Δx of all the inkjet heads becomes 0 so that the effective recording widths of the respective inkjet heads are the same. As described above, by adjusting the effective print width of each inkjet head so as to be equal to the average value of the effective print width when the module Δx is set to 0, the sum of the modules Δx of all the inkjet heads becomes 0. Become. In this case, the modules Δx may be evenly allocated or individually set in each of the inkjet heads as in the above embodiment. Further, after evenly allocating, the nozzle Δx may be measured and the module Δx may be finely adjusted. That is, the modules Δx may be individually fine-tuned so that the nozzles Δx are within the permissible range. However, also in this case, it is preferable to adjust so that the sum of the modules Δx of all the inkjet heads is 0.

<< Allowable range of nozzle Δx >>
As described above, by aligning the effective recording widths of the respective inkjet heads to the same width, the nozzle Δx can be kept within a certain range.

The range of the nozzle Δx to be accommodated, that is, the allowable range of the nozzle Δx is preferably within one pixel of the resolution composed of a single inkjet head from the viewpoint of preventing the replacement of dots (pixels). Further, from the viewpoint of facilitating the streak correction, it is more preferable that the resolution is 0.5 pixels or less, which is composed of a single inkjet head.

Here, the replacement of dots (pixels) will be described. The replacement of dots occurs because the characteristics of the head module (pitch between nozzles, discharge direction, etc.) are slightly different for each head module.

12 and 13 are diagrams showing a comparison of the lines recorded by the two head modules.

FIG. 12 shows an example when the pitches between the two head modules are the same. In FIG. 12, reference numeral 12A indicates a line recorded by the first head module, and reference numeral 12B indicates a line recorded by the second head module. Further, reference numeral 12C indicates a case where both are combined.

FIG. 13 shows an example in which the pitch between the modules of the two head modules is different (the pitch between the nozzles of the second head module is shorter than that of the first head module). In FIG. 13, reference numeral 13A indicates a line recorded by the first head module, and reference numeral 13B indicates a line recorded by the second head module. Further, reference numeral 13C indicates a case where both are combined.

Further, in each figure, odd-numbered reference numerals 1, 3, 5, ... Are attached to the lines recorded by the first head module in order, and even-numbered reference numerals 2 are attached to the lines recorded by the second head module. 4, 6, ... are attached in order.

As shown in FIG. 12, when the nozzle-to-nozzle pitches of the two head modules are the same, the positions of both lines are the same. Therefore, in this case, the dots (pixels) are not replaced.

On the other hand, as shown in FIG. 13, when the pitches between the nozzles of the two head modules are different, the lines may be exchanged in the middle. That is, the dots (pixels) may be replaced.

If the dots (pixels) are replaced, it becomes impossible to record a high-quality image. Therefore, from the viewpoint of preventing such dot (pixel) replacement, the allowable range of the nozzle Δx can be within one pixel of the resolution composed of a single inkjet head, that is, dot (pixel) replacement can be prevented. It is preferable to set it within the range.

Further, in consideration of streak correction, it is preferable that the resolution is 0.5 pixels or less, which is composed of a single inkjet head. As a result, streak correction can be easily performed without using means such as large droplets. Further, as a result of being able to correct streaks without using means such as large droplets, the waveform time of discharge can be shortened, and faster recording can be realized.

<< Fine adjustment after aligning the effective recording width >>
After aligning the effective recording widths of the respective inkjet heads, the nozzles Δx between the respective inkjet heads may be measured, and the position of the head module may be finely adjusted so that the nozzles Δx fall within the specified range. In this case, first, the nozzle Δx between the inkjet heads is measured, and a region where the nozzle Δx does not fall within the specified range is detected. If there is a region where the nozzle Δx is not within the specified range, the position of the head module is finely adjusted so that the nozzle Δx is within the specified range. As a result, the positional relationship between the inkjet heads can be adjusted with higher accuracy.

When a large number of inkjet heads are provided, adjusting the nozzles Δx among all the inkjet heads complicates the procedure. Therefore, when adjusting the nozzle Δx, it is also effective to adjust the nozzle Δx with reference to a specific inkjet head. For example, it is conceivable to adjust the nozzles Δx of other inkjet heads with reference to the inkjet head that ejects ink (for example, black ink) having high visibility with respect to streaks, unevenness, and the like.

As a result of making such adjustments, the effective recording widths of the respective inkjet heads may not be uniform. However, since the original purpose is to keep the nozzle Δx within a certain range, even if the effective recording widths of the respective inkjet heads are not aligned as a result, it is allowed in this case.

The adjustment can also be performed on an inkjet head basis. For example, the entire inkjet head may be shifted so that the nozzle Δx is within the specified range.

If the nozzle Δx is not within the specified range, the target value of the effective recording width to be aligned may be changed and readjusted.

<< Measurement of nozzle Δx >>
The nozzle Δx is measured by recording, for example, a predetermined test chart (test pattern). That is, a predetermined test chart is recorded, the recording result is read by the image reading unit 30, the image of the read test chart is analyzed, and the nozzle Δx between the inkjet heads is measured. At that time, in order to eliminate the influence of defective nozzles, it is preferable to measure the nozzle Δx by a line group or a dot group recorded by a plurality of nozzles.

FIG. 14 is a diagram showing an example of a test chart for measuring the nozzle Δx. FIG. 15 is an enlarged view of a part of FIG. 14 (a region surrounded by a frame shown by a broken line).

FIG. 14 shows an example of a test chart TC in which the nozzle Δx is measured by a plurality of line groups. The upper part of the test chart TC is the line L1 recorded by the first inkjet head 21A, and the lower part is the line L2 recorded by the second inkjet head 21B.

As shown in FIG. 14, the nozzle Δx is measured at a plurality of points for each head module. That is, a plurality of lines are recorded using a plurality of nozzles for each head module, and the nozzles Δx are measured at a plurality of points in the head module. Nozzle Δx is determined by measuring the distance between the lines recorded by the corresponding nozzle.

Nozzle Δx is measured at a plurality of points for each head module, and the average value thereof is obtained to obtain the nozzle Δx for each head module. In this way, by measuring the nozzles Δx at a plurality of points in the head module and using the average value thereof, the local deviation in the head module can be averaged. Therefore, it is preferable to set the measurement points evenly.

Although the measurement is performed discretely in this example, the nozzles Δx of all the nozzles in the head module may be obtained and averaged.

<< Measurement of effective recording width >>
As described above, the effective recording width can be measured by recording a predetermined test chart (test pattern). When it is difficult to actually measure the value, it can be measured as a relative value.

FIG. 16 is a diagram showing a measurement example when the effective recording width is measured as a relative value.

As shown in the figure, the relative positions of the head modules arranged at both ends of each inkjet head are measured, and the effective recording width of each inkjet head is acquired as a relative value.

Specifically, a measurement line is recorded using the corresponding nozzles 25A (R) and 25B (R) of the head module arranged at one end (right end), and the distance between the recorded lines W1-2 ( R) is measured. Similarly, the measurement lines are recorded using the corresponding nozzles 25A (L) and 25B (L) of the head module arranged at the other end (left end), and the distance between the recorded lines W1-2 ( L) is measured. The sum of the obtained distances W1-2 (R) and W1-2 (L) is the relative difference in effective recording width between the first inkjet head 21A and the second inkjet head 21B.

In this way, the effective recording width can also be acquired as a relative value. When the effective recording width is acquired as a relative value, it can also be acquired by measuring the nozzle Δx in the head modules at both ends. That is, the relative value of the effective recording width can be obtained by measuring the nozzle Δx between the head modules located at one end and the nozzle Δx between the head modules located at the other end and obtaining the sum thereof.

When the effective recording width is acquired as a relative value, the relative value is adjusted to 0. As a result, the effective recording width of each inkjet head can be made the same width.

<< Measurement of module Δx >>
As described above, the module Δx can also be measured by recording a predetermined test chart (test pattern) (see, for example, Japanese Patent Application Laid-Open No. 2014-83720).

In addition, the nozzle surface can be imaged with a camera, the obtained image data can be analyzed, and the module Δx can be measured.

<< Processing when some head modules are replaced >>
In an inkjet head configured by connecting a plurality of head modules, if a problem occurs in a part of the head modules, the head modules can be replaced. When the head module is replaced, the head module may be mounted at the same position as before the replacement, or the module Δx may be adjusted and mounted on both sides so that the modules Δx are even. Further, the nozzle Δx may be measured after mounting and finely adjusted so that the nozzle Δx is within the allowable range. If the nozzle Δx does not fall within the allowable range, the effective print width may be readjusted.

<< Other examples of inkjet recording devices >>
INDUSTRIAL APPLICABILITY The present invention can be widely applied to a general range of an inkjet recording device including a plurality of line-type inkjet heads configured by connecting a plurality of head modules. Therefore, the type of the medium, the transport form, and the like are not particularly limited.

Further, as described above, the mounted inkjet head may be an inkjet head that ejects ink of the same type or color, or may be an inkjet head that ejects ink of a different type or color.

<< Other examples of inkjet heads >>
In the above embodiment, the case where the nozzles are arranged in a matrix on the nozzle surface of each head module has been described as an example, but the arrangement of the nozzles provided in each head module is not limited to this. It may be arranged in a straight line.

Further, in the above-described embodiment, the example in which the head modules are connected in a straight line has been described, but the form in which the head modules are connected is not limited to this. Any arrangement may be used as long as the resolution can be almost uniform over the entire recording width.

[Inkjet head adjustment support device]
"Constitution"
FIG. 17 is a block diagram showing an embodiment of the inkjet head adjustment support device.

The inkjet head adjustment support device is configured as a device that automatically outputs a target value of a module Δx necessary for aligning the effective recording widths of the respective inkjet heads mounted on the inkjet recording device to the same width.

FIG. 17 shows an example in which the inkjet head adjustment support device 110 is incorporated in the inkjet recording device 1. The function of the inkjet head adjustment support device 110 is provided by the control unit 100.

The control unit 100 functions as the inkjet head adjustment support device 110 by executing a predetermined program (injection head adjustment support program).

As shown in FIG. 17, the inkjet head adjustment support device 110 includes a module Δx measurement unit 110A, an effective recording width measurement unit 110B, an effective recording width calculation unit 110C, a target value calculation unit 110D, and an output unit 110E. The control unit 100, which is a computer, realizes these functions by executing a predetermined program.

The module Δx measuring unit 110A measures the module Δx of each inkjet head mounted on the inkjet recording device. The module Δx measuring unit 110A analyzes the recording result of a predetermined test chart and measures the module Δx of each inkjet head. The recording result of the test chart is acquired from the image reading unit 30 as image data.

The effective recording width measuring unit 110B measures the effective recording width of each inkjet head mounted on the inkjet recording device. The effective recording width measuring unit 110B analyzes the recording result of a predetermined test chart and measures the effective recording width of each inkjet head. The recording result of the test chart is acquired from the image reading unit 30 as image data.

The module Δx measuring unit 110A and the effective recording width measuring unit 110B are examples of information acquisition units that acquire information on the module Δx of the inkjet head and information on the effective recording width.

The effective recording width calculation unit 110C calculates the effective recording width of each inkjet head when the module Δx is set to 0, based on the measurement results of the module Δx measuring unit 110A and the effective recording width measuring unit 110B.

The target value calculation unit 110D calculates the target value of the module Δx of each inkjet head based on the information of the effective recording width of each inkjet head when the module Δx is set to 0. That is, the target value of the module Δx required for aligning the effective recording widths of all the inkjet heads to the same width is calculated. For example, the average value of the effective recording width of each inkjet head when the module Δx is set to 0 is obtained, and the module Δx is evenly allocated so as to be equal to the obtained average value, and the target value of the module Δx is calculated.

The output unit 110E outputs the information of the target value of the module Δx for each inkjet head calculated by the target value calculation unit 110D to a predetermined output destination in a predetermined format. In the present embodiment, the output is output to the display unit 102.

《Action》
The control unit 100 starts the adjustment support process according to the instruction from the user. The user instructs the start of support for adjustment via the operation unit 101.

When the support start is instructed, the control unit 100 first measures the module Δx and the effective recording width of each inkjet head. The measurement of module Δx and effective recording width is performed by recording a predetermined test chart. The control unit 100 feeds the paper P from the paper feed unit 40, and causes the inkjet heads 21A and 21B to record a test chart. In addition, the recorded test chart is read by the image reading unit 30. The read image data of the test chart is added to the module Δx measuring unit 110A and the effective recording width measuring unit 110B.

The module Δx measuring unit 110A analyzes the acquired image data of the test chart and measures the module Δx of each inkjet head. Further, the effective recording width measuring unit 110B analyzes the acquired image data and measures the effective recording width of each inkjet head. The measured information on the module Δx of each inkjet head and the information on the effective recording width are added to the effective recording width calculation unit 110C.

The effective recording width calculation unit 110C calculates the effective recording width of each inkjet head when the module Δx is set to 0, based on the acquired information on the module Δx of each inkjet head and the information on the effective recording width. The calculated effective print width information is added to the target value calculation unit 110D.

The target value calculation unit 110D calculates the target value of the module Δx of each inkjet head based on the information of the effective recording width of each inkjet head when the module Δx is set to 0. That is, the target value of the module Δx required to align the effective recording widths of all the inkjet heads to the same width is calculated for each inkjet head. The calculated target value information of the module Δx for each inkjet head is added to the output unit 110E.

The output unit 110E outputs the target value of the module Δx for each inkjet head calculated by the target value calculation unit 110D to the display unit 102 in a predetermined format.

The user adjusts the module Δx of each inkjet head based on the information displayed on the display unit 102.

As described above, by providing the inkjet head adjustment support device 110, information necessary for adjusting each inkjet head can be easily obtained.

<< Modification example >>
In the present embodiment, the case where the inkjet head adjustment support device is incorporated in the inkjet recording device has been described as an example, but the inkjet head adjustment support device can also be configured as a single device. For example, it can be configured by a computer communicatively connected to an inkjet recording device.

Further, in the above embodiment, the information of the module Δx of each inkjet head and the information of the effective print width are automatically acquired by recording the test chart, but the information of the module Δx of each inkjet head and the information of the effective print width are obtained. The effective print width information may be manually input. Further, the information of the image data of the test chart read by another device may be acquired, and the information of the module Δx of each inkjet head and the information of the effective print width may be acquired.

Further, in the above embodiment, the result is output to the display unit 102, but the output destination of the result is not limited to this. In addition, for example, the result may be recorded on paper P and output.

Further, it may have a function of finely adjusting the nozzle Δx. That is, it may further have a function of measuring the nozzle Δx between the inkjet heads and a function of calculating the adjustment amount of the module Δx required to keep the nozzle Δx within the specified range based on the measurement result. ..

Further, the inkjet head having a function of automatically adjusting the position of each head module may be configured to be automatically adjusted based on the calculated target value. For example, for an inkjet head in which the position of each head module can be adjusted by an actuator, the actuator may be driven to automatically adjust the position of each head module.

<< Other variants >>
In the above embodiment, the inkjet head adjustment support device is realized by a computer, but the hardware configuration for realizing these functions is not limited to this. It can be configured with various processors. For various processors, circuit configurations after manufacturing such as CPU (Central Processing Unit) and FPGA (ield Programmable Gate Array), which are general-purpose processors that function as processing units that execute software (programs) to perform various processes. It includes a dedicated electric circuit, which is a processor having a circuit configuration specially designed to execute a specific process such as PLD (Programmable Logic Device), which is a processor capable of changing the CPU, and ASIC (Application Specific Integrated Circuit). ..

One processing unit may be composed of one of these various processors, or may be composed of two or more processors of the same type or different types. For example, it may be composed of a plurality of FPGAs, or may be composed of a combination of a CPU and an FPGA.

Further, a plurality of processing units may be configured by one processor. As an example of configuring a plurality of processing units with one processor, first, as represented by a computer such as a client and a server, one processor is configured by combining one or more CPUs and software. There is a form in which this processor functions as a plurality of processing units. Second, a processor that realizes the functions of the entire system including a plurality of processing units with one IC chip (IC: Integrated Circuit) is used, as typified by System On Chip (SoC). There is a form. As described above, the various processing units are configured by using one or more of the above-mentioned various processors as a hardware-like structure.

Further, the hardware structure of these various processors is, more specifically, an electric circuit in which circuit elements such as semiconductor elements are combined.

1 Inkjet recording device 7A Initial state of each inkjet head 7B State in which module Δx of each inkjet head is set to 0 7C State in which adjustment of each inkjet head is completed 9A Initial state of each inkjet head 9B Module Δx of each inkjet head is set to 0 9C The adjustment of each inkjet head is completed. 10 Paper transfer unit 11 Belt 12 Drive roller 13 Driven roller 12A Line 12B recorded by the first head module Line 12C Recorded by the second head module Synthesis of lines recorded by the head module and the second head module 13A Line recorded by the first head module 13B Line recorded by the second head module 13C In the first head module and the second head module Synthesis of recorded lines 14 Belt drive motor 16 Suction unit 20 Inkjet recording unit 21A Inkjet head (first inkjet head)
21B Inkjet Head (2nd Inkjet Head)
21C Inkjet Head (3rd Inkjet Head)
22A head module (head module constituting the first inkjet head)
22B head module (head module constituting the second inkjet head)
23A Base 24A Nozzle surface 25A Nozzle 30 Image reading unit 31 Image reading device 40 Feeding unit 50 Paper ejection unit 100 Control unit 101 Operation unit 102 Display unit 103 Communication unit 104 Storage unit 110 Inkjet head adjustment support device 110A Module Δx measurement unit 110B Effective recording width measurement unit 110C Effective recording width calculation unit 110D Target value calculation unit 110E Output unit P Paper TC test chart L1 Line recorded by the first inkjet head L2 Line recorded by the second inkjet head S1 to S4 Each inkjet head Procedure for adjusting the relative positional relationship between

Claims (18)

A method for adjusting an inkjet head, which adjusts the relative positional relationship between the inkjet heads in an inkjet recording apparatus provided with a plurality of line-type inkjet heads configured by connecting a plurality of head modules.
In each of the above-mentioned inkjet heads, by adjusting the distance between the adjacent head modules, the effective recording widths of all the above-mentioned inkjet heads are made to be the same width, and the distance between the adjacent head modules with respect to the reference interval is set. When the amount of deviation is the module Δx, each of the above-mentioned inkjet heads has a step of equalizing the above-mentioned module Δx and aligning the effective recording widths of all the above-mentioned inkjet heads with the same width.
A method for adjusting the inkjet head of an inkjet recording device. A method for adjusting an inkjet head, which adjusts the relative positional relationship between the inkjet heads in an inkjet recording apparatus provided with a plurality of line-type inkjet heads configured by connecting a plurality of head modules.
In each of the above-mentioned inkjet heads, by adjusting the distance between the adjacent head modules, the effective recording widths of all the above-mentioned inkjet heads are made to be the same width, and the distance between the adjacent head modules with respect to the reference distance is set. When the amount of deviation is the module Δx, the sum of the modules Δx of all the inkjet heads is set to 0, and there is a step of aligning the effective recording widths of all the inkjet heads to the same width.
A method for adjusting the inkjet head of an inkjet recording device. Further, in each of the above-mentioned inkjet heads, the module Δx is equalized so that the effective recording widths of all the above-mentioned inkjet heads are made the same width.
The method for adjusting an inkjet head of an inkjet recording device according to claim 2. The reference interval is an interval at which the resolution is kept uniform at the joint of the adjacent head modules.
The method for adjusting an inkjet head of an inkjet recording device according to any one of claims 1 to 3. For each of the above-mentioned inkjet heads, a step of measuring the module Δx and the effective recording width, and
For each of the above-mentioned inkjet heads, a step of obtaining an effective recording width when the module Δx is set to 0, and
Based on the information on the effective recording width when the module Δx is set to 0, the step of obtaining the target value of the module Δx for each of the inkjet heads required to align the effective recording widths of all the inkjet heads with the same width. When,
Further have,
The method for adjusting an inkjet head of an inkjet recording device according to any one of claims 1 to 3. The average value of the effective recording width when the module Δx is set to 0 is obtained, and the target value of the module Δx for each of the inkjet heads required to align the effective recording widths of all the inkjet heads with the average value is obtained. ,
The method for adjusting an inkjet head of an inkjet recording device according to claim 5. The target value of the module Δx for each of the inkjet heads required for aligning with the effective recording width of the specific inkjet head when the module Δx is set to 0 is obtained.
The method for adjusting an inkjet head of an inkjet recording device according to claim 5. A test chart is recorded with each of the above-mentioned inkjet heads, and the above-mentioned module Δx and the effective recording width are measured.
The method for adjusting an inkjet head of an inkjet recording device according to any one of claims 5 to 7. The amount of deviation of the nozzle position that occurs between the inkjet heads is defined as the nozzle Δx.
After aligning the effective recording widths of all the inkjet heads to the same width, a step of detecting a region where the nozzle Δx does not fall within the specified range, and a step of detecting the region.
A step of finely adjusting the position of the head module in a region where the nozzle Δx is not within the specified range, and
Further have,
The method for adjusting an inkjet head of an inkjet recording device according to any one of claims 1 to 8. As the specified range, the resolution is within one pixel of the resolution composed of the single inkjet head.
The method for adjusting an inkjet head of an inkjet recording device according to claim 9. As the specified range, the resolution is within 0.5 pixel of the resolution composed of the single inkjet head.
The method for adjusting an inkjet head of an inkjet recording device according to claim 9. It is an inkjet recording device equipped with a plurality of line-type inkjet heads configured by connecting a plurality of head modules.
The inkjet heads have the same effective recording width, respectively.
And,
When the amount of deviation between the intervals between adjacent head modules with respect to the reference interval is set to module Δx, the modules Δx in each of the inkjet heads are equal.
Inkjet recording device. It is an inkjet recording device equipped with a plurality of line-type inkjet heads configured by connecting a plurality of head modules.
The plurality of the inkjet heads each have the same effective recording width, and the plurality of said inkjet heads have the same effective recording width.
And,
When the amount of deviation between the intervals of the adjacent head modules with respect to the reference interval is set to the module Δx, the sum of the modules Δx of all the inkjet heads is 0.
Inkjet recording device. Further, the module Δx in each of the above-mentioned inkjet heads is equal.
The inkjet recording apparatus according to claim 13. The reference interval is an interval at which the resolution is kept uniform at the joint of the adjacent head modules.
The inkjet recording apparatus according to any one of claims 12 to 14. Further provided with a control unit for controlling the drive of the inkjet head.
When a defective nozzle is generated in one of the above-mentioned inkjet heads, the control unit makes the defective nozzle non-ejective and complements it with ejection from the other one of the inkjet heads.
The inkjet recording apparatus according to any one of claims 12 to 15. An inkjet head adjustment support device that supports adjustment of the relative positional relationship between the inkjet heads in an inkjet recording device provided with a plurality of line-type inkjet heads configured by connecting a plurality of head modules.
When the amount of deviation between the intervals of the adjacent head modules with respect to the reference interval is set to the module Δx, the information acquisition unit for acquiring the information of the module Δx and the information of the effective recording width of each of the inkjet heads.
For each of the above-mentioned inkjet heads, an effective recording width calculation unit for calculating an effective recording width when the module Δx is set to 0, and an effective recording width calculation unit.
Based on the information on the effective recording width when the module Δx is set to 0, the target value of the module Δx for each of the inkjet heads required to align the effective recording widths of all the inkjet heads with the same width is calculated. Target value calculation unit and
An output unit that outputs the calculated target value of the module Δx for each of the inkjet heads,
An inkjet head adjustment support device for an inkjet recording device equipped with. An inkjet head adjustment support program that supports adjustment of the relative positional relationship between the inkjet heads in an inkjet recording device provided with a plurality of line-type inkjet heads configured by connecting a plurality of head modules.
When the amount of deviation between the intervals between adjacent head modules with respect to the reference interval is set to module Δx, the function of acquiring the information of the module Δx and the information of the effective recording width of each of the inkjet heads, and
For each of the above-mentioned inkjet heads, a function of calculating an effective recording width when the module Δx is set to 0, and
Based on the information on the effective recording width when the module Δx is set to 0, the target value of the module Δx for each of the inkjet heads required to align the effective recording widths of all the inkjet heads with the same width is calculated. Function and
A function to output the calculated target value of the module Δx for each of the inkjet heads, and
An inkjet head adjustment support program for an inkjet recording device that realizes this in a computer.

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