JP7602724B2 - Nozzle switching position setting method, liquid ejection head device, liquid ejection unit, and program - Google Patents

Description

The present invention relates to a nozzle switching position setting method, a liquid ejection head device, a liquid ejection unit, and a program.

Conventionally, there is known a liquid ejection head device in which the nozzle row of one of two liquid ejection heads, each of which has a plurality of nozzles arranged therein, is arranged so as to overlap partially with the nozzle row of the other liquid ejection head.

For example, Patent Document 1 discloses a line recording head (liquid ejection head device) in which the nozzle pitch of the nozzle row of one recording head (liquid ejection head) is arranged at P1, and the nozzle pitch of the nozzle row of the other recording head is arranged at P2 (<P1). In Patent Document 1, in a recording inspection process after assembling the line recording head, a nozzle switching position is set to switch the effective nozzles that perform liquid ejection operation in the overlapping area between one recording head and the other recording head from the nozzles of one recording head to the nozzles of the other recording head. Specifically, the nozzle switching position is shifted one by one to perform dot recording on the recording material (recording material), and the nozzle switching position is set when the switching point between one recording head and the other recording head is indistinguishable by the operator's eyes. This suppresses recording unevenness due to pitch deviation at the switching point of the recording width between the recording heads, even without performing high-precision alignment between the recording heads.

However, conventionally, the nozzle switching position has been set by the worker's visual inspection, which places a heavy burden on the worker and makes it difficult to set the nozzle switching position.

In order to solve the above-mentioned problems, the present invention provides a liquid ejection head device in which two liquid ejection heads, each having a plurality of nozzles arranged therein, are arranged to be shifted in a direction perpendicular to the head longitudinal direction so that a head longitudinal range of a nozzle row in one of the two liquid ejection heads partially overlaps with a head longitudinal range of a nozzle row in the other liquid ejection head, and a nozzle switching position setting method for switching effective nozzles that perform liquid ejection operations within the overlapping area from the nozzles of one liquid ejection head to the nozzles of the other liquid ejection head, the method comprising: a first ejection position pattern created by ejecting liquid from the nozzles of one liquid ejection head; The method includes a reading step of reading, with a reading device, a second ejection position pattern created by ejecting liquid from the nozzles of the liquid ejection head; a setting step of setting the nozzle switching position based on the ejection position in the head longitudinal direction of each nozzle obtained from each ejection position pattern read in the reading step; and a slope specifying step of creating a line image extending in a direction perpendicular to the head longitudinal direction by liquid ejected multiple times from at least one nozzle, reading the line image with the reading device, and specifying the slopes of the first ejection position pattern and the second ejection position pattern from the slope of the read line image, wherein in the setting step, the nozzle switching position is set based also on the slope specified in the slope specifying step .

The present invention has the excellent effect of reducing the workload of the operator and making it easier to set the nozzle switching position.

FIG. 4 is a plan view of the head unit according to the embodiment, as viewed from the normal direction of the recording material. FIG. 2 is an explanatory diagram showing the head arrangement of the recording heads provided for each recording section of the head unit. 5A and 5B are explanatory diagrams showing the relationship between the nozzle pitches of two recording heads arranged adjacent to each other along the longitudinal direction of the heads. FIG. 2 is a block diagram showing the hardware configuration of a control system of an inkjet printing apparatus equipped with the head unit. FIG. 2 is a block diagram showing a hardware configuration of a head driving section of the head unit. 13A to 13F are explanatory diagrams showing examples of test charts in which image recording (dot ejection) is performed by shifting the nozzle switching positions one by one in the overlapping region of two recording heads. 1A is an explanatory diagram showing the nozzle arrangement of two print heads, and FIG. 1B is a diagram showing an example of a test chart (ejection position pattern) formed on a printing material. 1A is an explanatory diagram showing the nozzle arrangement of two print heads, and FIG. 1B is a diagram showing another example of a test chart (ejection position pattern) formed on a printing material. 1A is a diagram showing a test chart made up of isolated dots formed on a recording material, and FIG. 1B is a diagram showing a read image obtained by reading the isolated dots of the test chart; 6 is a graph plotting image density (pixel value) in the longitudinal direction of the head for the dot portion of the read test chart. 1A is a diagram showing a test chart made up of a line pattern formed on a recording material, and FIG. 1B is a diagram showing a read image obtained by reading the line pattern of the test chart; 6 is a diagram showing an example of a rotation correction chart used for performing rotation correction on a read image. FIG. 13A and 13B are diagrams showing another example of the rotation correction chart used for performing rotation correction on a read image. FIG. 13 is a plan view illustrating a main portion of another example of a device for discharging liquid. FIG. FIG. 13 is a plan view illustrating a main portion of another example of the liquid ejection unit. FIG. 13 is a front view illustrating still another example of the liquid ejection unit.

The following describes an embodiment in which the present invention is applied to a head unit equipped with a liquid ejection head device of an inkjet recording device, which is an image forming device that ejects liquid.

First, the head unit in this embodiment will be described.
FIG. 1 is a plan view of the head unit 2 as viewed from the normal direction of a recording material P0.
The recording material P0 is, for example, paper, and may be roll paper (continuous paper) or cut paper. It may also be various media other than paper. The recording material P0 is transported along the transport direction indicated by the arrow in Fig. 1. The head unit 2 is supported so as to face the recording surface of the recording material P0 at a predetermined distance.

The head unit 2 is equipped with a K recording section 2K, a C recording section 2C, an M recording section 2M, and a Y recording section 2Y as liquid ejection head devices for each color, which are provided corresponding to the inks (liquids) of black (K), cyan (C), magenta (M), and yellow (Y). In other words, the head unit 2 is composed of a combination of four liquid ejection head devices.

As shown in FIG. 1, in the recording units 2K, 2C, 2M, and 2Y of each color, the recording heads 3 and 4 as liquid ejection heads are arranged in a staggered pattern along the recording material width direction (direction perpendicular to the transport direction), which is the head longitudinal direction, in the present embodiment. For convenience of explanation, the odd-numbered recording heads counting from the left in FIG. 1 will be described as recording heads 3 and the even-numbered recording heads as recording heads 4, but there is no difference in configuration or function between recording heads 3 and 4.

The head unit 2 ejects ink droplets from the nozzles of the recording units 2K, 2C, 2M, and 2Y of each color in synchronization with the position of the recording material being transported, forming a color image on the recording material P0. The number of recording units mounted on the head unit 2, the number of recording heads arranged in the recording units, and the color of ink ejected from the recording units can be set arbitrarily. Thus, for example, the head unit 2 may be a head unit that includes only the black recording unit 2K and prints in black alone.

FIG. 2 is an explanatory diagram showing the head arrangement of the recording heads 3 and 4 provided for each recording section of the head unit 2. As shown in FIG.
The recording head 3 and the recording head 4 each have a nozzle row in which a plurality of nozzles 5 are arranged along the longitudinal direction of the head. In this embodiment, an example in which there is one nozzle row will be described, but a configuration in which two or more nozzle rows are arranged in the recording material transport direction may also be used. Furthermore, the nozzle row may be arranged so that the nozzle row direction is inclined with respect to the longitudinal direction of the head.

In addition, as shown in FIG. 2, on one recording unit in this embodiment, one of two recording heads 3, 4 arranged adjacent to each other along the head longitudinal direction is arranged so that one recording head 3 partially overlaps the other recording head 4. By arranging the recording heads 3, 4 in this manner, the recording range in the head longitudinal direction in the entire recording unit (the range in which an image can be recorded by ink ejected from the nozzles 5) can be expanded. As a result, a recording unit with a recording range spanning the width of the recording material P0 can be obtained, and a line-type head unit 2 can be realized, so that an image can be formed on the recording material P0 in one pass without scanning the head unit 2.

3A and 3B are explanatory diagrams showing the relationship of the nozzle pitch of two recording heads 3 and 4 arranged adjacent to each other along the head longitudinal direction.
The nozzle array provided in the recording heads 3 and 4 shown in FIG. 3A includes a normal region as a first nozzle group in which the nozzles 5 are arranged at a normal pitch P1, and a narrow region as a second nozzle group in which the nozzles 5 are arranged at a pitch P2 narrower than the normal pitch P1. In this example, most of the nozzle array is the normal region, but a narrow region is provided only on one end side of the nozzle array. Instead of the narrow region, a wide region in which the nozzles 5 are arranged at a pitch wider than the normal pitch P1 may be used. In this example, the normal region of the recording head 3 and the narrow region of the recording head 4 are arranged so as to overlap in the overlapping range (overlap region) between the recording heads 3 and 4.

The nozzle array provided in the recording heads 3 and 4 shown in FIG. 3(b) has a normal region with a normal pitch P3, a wide region as a first nozzle group with a pitch P1 wider than the normal pitch P3, and a narrow region as a second nozzle group with a pitch P2 narrower than the normal pitch P3. In this example, most of the nozzle array is the normal region, but a narrow region is provided at one end of the nozzle array, and a wide region is provided at the other end of the nozzle array. In this example, the wide region of recording head 3 and the narrow region of recording head 4 are arranged to overlap in the overlapping range (overlap region) between recording head 3 and recording head 4.

In other words, in this embodiment, it is sufficient that the nozzle pitch P2 of the recording head 3 and the nozzle pitch P1 of the recording head 4 are configured to be different in the overlapping range (overlap area) between the recording head 3 and the recording head 4. With this configuration, even if the recording head 3 and the recording head 4 are not positioned with high precision, the nozzle that minimizes the head longitudinal position deviation between the recording head 3 and the recording head 4 in the overlap area is determined. Therefore, if each recording head is operated so that the nozzle used by each recording head 3, 4 (effective nozzle) is switched with this nozzle, recording unevenness due to pitch deviation at the switching point of the recording width between the recording heads 3, 4 can be suppressed.

The nozzle (nozzle switching position) at which the deviation in the head longitudinal direction position between recording head 3 and recording head 4 is minimal may be, for example, a position at which the distance between dots (dot pitch) cannot be distinguished when ink is actually ejected after the head unit 2 is assembled. Therefore, it does not matter if the deviation in the head longitudinal direction position between recording head 3 and recording head 4 is not minimal. The set nozzle switching position is stored in memory unit 620, which will be described later. The method for setting the nozzle switching position in this embodiment will be described in detail later.

In this embodiment, in the example of FIG. 3(a), both the normal pitch P1 and the narrow pitch P2 are set to be the same pitch between the recording head 3 and the recording head 4. Therefore, the recording head 3 and the recording head 4 can be configured identically. The same is true for the example of FIG. 3(b). Therefore, the recording unit of this embodiment can be manufactured by preparing only one type of recording head, and manufacturing costs can be kept low compared to when the recording head 3 and the recording head 4 have different configurations.

FIG. 4 is a block diagram showing the hardware configuration of a control system of the inkjet recording apparatus 1 equipped with the above-mentioned head unit 2. As shown in FIG.
In addition to the head unit 2 described above, the inkjet recording apparatus 1 is configured with a control unit 600 , a transport drive unit 710 , an operation display unit 720 , and an input/output interface 730 , all of which are interconnected via a bus line 740 .

The head unit 2 is equipped with a head drive section 20 that drives the recording heads 3, 4 arranged in the recording sections 2K, 2C, 2M, 2Y of each color. The head drive section 20 generates a drive waveform that deforms each piezoelectric element, which is an electromechanical conversion element acting as an actuator in each recording head 3, 4 of each recording section 2K, 2C, 2M, 2Y, in response to a control signal input from the control section 600. When this drive waveform is input to each piezoelectric element of each recording head 3, 4 of each recording section 2K, 2C, 2M, 2Y, the liquid in the pressure chamber communicating with the nozzle 5 is pressurized, ejection energy is applied, and ink is ejected from the corresponding nozzle 5.

The control unit 600 has a CPU (Central Processing Unit) 610, a storage unit 620, a RAM (Random Access Memory) 630, and a ROM (Read Only Memory) 640. The CPU 610 reads out various control programs and setting data stored in the ROM 640, stores them in the RAM 630, executes them, and performs various calculation processes. The CPU 610 also controls the overall operation of the inkjet recording device 1.

The memory unit 620 stores a print job (image recording command) input via the input/output interface 730, image data (image information) to be printed, and a nozzle switching position that is set based on a nozzle switching position detection pattern (ejection position pattern) described below.

The conveyance driving section 710 supplies a drive signal to a conveyance motor based on a control signal supplied from the control section 600, and conveys the recording material P0 at a predetermined speed and timing.
The operation display unit 720 includes a display device such as a liquid crystal display or an organic EL display, and an input device such as a touch panel arranged over the screen of the display device and operation keys. The operation display unit 720 displays various information on the display device, and also supplies the control unit 600 with an operation signal corresponding to a user's input operation on the input device.
The input/output interface 730 mediates the transmission and reception of data between the external device 800 and the control unit 600 .
The bus line 740 is a path for transmitting and receiving signals between the control unit 600 and other components.

FIG. 5 is a block diagram showing the hardware configuration of the head driving section 20 of the head unit 2. As shown in FIG.
In FIG. 5, for the sake of simplicity, only one recording head 3 is shown, and the other recording heads are omitted.

The head driving unit 20 includes driving waveform correction units 21-1 to 21-N corresponding to the nozzles 5-1 to 5-N (where "N" is the number of nozzles on the recording head 3) on the recording head 3, a head control unit 22, a basic driving waveform generation unit 23, and a driving waveform correction information storage unit 24.

The head control unit 22 converts the image data input from the control unit 600 into control signals for the recording heads 3 and the nozzles 5-1 to 5-N of the recording heads 4 of the recording units 2K, 2C, 2M and 2Y.
Based on a control signal input from the head control unit 22, the basic drive waveform generation unit 23 generates a basic drive waveform that enables a reference ejection operation according to the image pattern, transport speed, and printing environment such as temperature and humidity.
The drive waveform correction information storage unit 24 stores information indicating the nozzle numbers of nozzles that require correction, and information indicating the amount of correction.

The drive waveform correction units 21-1 to 21-N correct the basic drive waveform of the drive voltage supplied from the basic drive waveform generation unit 23 based on the correction information read from the drive waveform correction information storage unit 24, and supply it to each piezoelectric element corresponding to the nozzles 5-1 to 5-N. This makes it possible to give each of the nozzles 5-1 to 5-N different ejection characteristics individually, enabling appropriate ink ejection from each of the nozzles 5-1 to 5-N.

In this embodiment, different ejection characteristics are assigned to each nozzle, but this is not limited to the above. In other words, ejection characteristics may be assigned to each nozzle row, or each area with a different pitch. The unit for assigning the ejection characteristics may be determined based on constraints such as the memory of the device and the load of the applied voltage.

FIG. 6 is an explanatory diagram showing an example of a conventional test chart printed on the recording material P0.
6(a) to 6(f) are obtained by shifting the nozzle switching position one by one in the overlap region of the recording head 3 and the recording head 4 shown in Fig. 3(a) and recording (ejecting dots). Note that the open circles in Fig. 6 indicate dots made of ink ejected from the nozzles of the recording head 3, and the filled circles in Fig. 6 indicate dots made of ink ejected from the nozzles of the recording head 4.

In the example of the nozzle switching position shown in Figure 6(a), the distance between the extreme dot on recording head 3 (the right end in Figure 6) and the extreme dot on recording head 4 (the left end in Figure 6) is too close. Therefore, the inter-dot distance Xa is significantly different from the inter-dot distance X1 corresponding to the normal region and the inter-dot distance X2 corresponding to the narrow region. In this case, the dot density at this nozzle switching position is locally high, and the image density at the position in the head longitudinal direction corresponding to that nozzle switching position is locally high, causing uneven image density in the head longitudinal direction.

In addition, in the example of the nozzle switching position shown in Figure 6(f), the distance between the extreme dot on recording head 3 (the right end in Figure 6) and the extreme dot on recording head 4 (the left end in Figure 6) is too far. Therefore, the inter-dot distance Xf is significantly different from the inter-dot distance X1 corresponding to the normal region and the inter-dot distance X2 corresponding to the narrow region. In this case, the dot density at this nozzle switching position is locally low, and therefore the image density at the position in the head longitudinal direction corresponding to that nozzle switching position is locally low, again causing uneven image density in the head longitudinal direction.

Of the examples shown in Figures 6(a) to (f), the example in which the nozzle switching position is shown in Figure 6(d) can minimize the deviation from the dot-to-dot distance X1 corresponding to the normal region and the dot-to-dot distance X2 corresponding to the narrow region. In this case, the dot density at this nozzle switching position is approximately the same as the dot density in the locations corresponding to the normal region and narrow region, suppressing image density unevenness in the longitudinal direction of the head.

Conventionally, the nozzle switching position that minimizes the deviation has been determined by an operator visually checking a test chart and determining the position that is deemed to have the least image density unevenness. However, this method places a heavy burden on the operator and makes it difficult to set the nozzle switching position.

Therefore, in this embodiment, the created test chart (ejection position pattern) is read by a reading device such as a scanner or camera (imaging device). This test chart includes a first ejection position pattern created by ejecting liquid from the nozzles of one recording head 3, and a second ejection position pattern created by ejecting liquid from the nozzles of the other recording head 4. The read information of the read test chart is then image-processed to obtain the ejection position of each nozzle in the head longitudinal direction, and the nozzle switching position that minimizes the deviation is set.

According to this embodiment, it is no longer necessary for the worker to visually set the nozzle switching position, which reduces the burden on the worker and makes it easier to set the nozzle switching position.

7A and 7B are explanatory diagrams showing an example of a test chart (ejection position pattern) formed on the recording material P0.
Here, an example will be described in which the nozzle arrangement of each of the recording heads 3 and 4 includes four nozzle rows arranged along the head longitudinal direction (X direction) as shown in Fig. 7A. In this example, too, the recording heads 3 and 4 are arranged so that the ends of the recording heads 3 and 4 overlap, and multiple nozzles are located within the overlapping region.

Figure 7(b) shows a test pattern consisting of a dot pattern formed by ejecting multiple droplets from the nozzles of each of the recording heads 3 and 4 shown in Figure 7(a) and transporting the recording material in the recording material transport direction so that the dots formed by each droplet do not overlap each other. The test pattern shown in Figure 7(b) includes dots formed by droplets ejected multiple times from each nozzle of each of the recording heads 3 and 4, but it is sufficient that the test pattern includes dots formed by droplets ejected one or more times from each nozzle.

The test pattern created in this way is formed on a recording material and is read by a reading device installed in the inkjet recording device, or a reading device (external device 800) installed outside the inkjet recording device. Here, we will explain the case where the test pattern is read by a reading device installed in the inkjet recording device.

The read information of the read test chart is sent from the reading device to the control unit 600, where it is image-processed. This allows the position of each dot on the test chart (the ejection position in the head longitudinal direction of each nozzle corresponding to the dot) to be measured. In this case, as shown in FIG. 7(b), when multiple dots are created for one nozzle, the measurement accuracy of the dot position of the nozzle (the ejection position of the nozzle) can be improved by, for example, taking the average of the multiple dots.

Next, the control unit 600 sets the nozzle switching position between recording head 3 and recording head 4 with reference to the measured dot position of each nozzle, and determines the effective nozzles of recording head 3 and recording head 4. As a setting condition for the nozzle switching position, for example, a condition can be adopted in which the inter-dot distance X (distance in the head longitudinal direction = X direction) between the dots by recording head 3 and the dots by recording head 4 is selected as X2 < X < X1 (see FIG. 6). However, this is not limited to this, and other conditions may be adopted, such as a condition in which the inter-dot distance X is closest to the inter-dot distance X1 in the normal region.

In this example, for example, from among the nozzles of the recording head 3 with a narrow pitch P2 in the overlap region, a nozzle whose ejection position in the head longitudinal direction is located between two adjacent nozzles n, n+1 of the recording head 4 with a wide pitch P1 is identified. Then, the nozzle switching position is set with the ejection position of the identified nozzle of the recording head 3 as the nozzle at the nozzle switching position. Note that "n" is a number smaller than the number of nozzles N in the nozzle row.

Specifically, two adjacent nozzles n, n+1 on the recording head 4 with the wide pitch P1 are selected in sequence, and a nozzle on the recording head 3 with the narrow pitch P2 whose ejection position is located between the two nozzles n, n+1 selected in sequence is selected in sequence. Then, a nozzle combination that minimizes the deviation between one of the two nozzles n, n+1 on the recording head 4 and the nozzle on the recording head 3 is identified, and the identified nozzle is set as the nozzle switching position.

8A and 8B are explanatory diagrams showing other examples of the test chart (ejection position pattern) formed on the recording material P0.
Here, too, an example will be described in which the nozzle arrangement of each of the recording heads 3 and 4 includes four nozzle rows arranged along the head longitudinal direction (X direction) as shown in Fig. 8(a). In this example, too, the recording heads 3 and 4 are arranged so that the ends of the recording heads 3 and 4 overlap, and multiple nozzles are positioned within the overlapping region.

Figure 8(b) is a diagram showing a test pattern consisting of a dot pattern in this example. The test pattern shown in Figure 8(b) includes dots formed by droplets ejected multiple times from each of the selected nozzles, which are arbitrarily selected from the nozzles on each of the recording heads 3 and 4 (in this example, one nozzle for each of the recording heads 3 and 4). Note that it is sufficient that the test pattern includes dots formed by droplets ejected one or more times from each of the selected nozzles.

At this time, the nozzles selected from each recording head 3, 4 can be selected arbitrarily, and may be nozzles in any nozzle row, any nozzle in any head longitudinal position, or nozzles in or outside the overlapping region. The number of nozzles selected may be one or more, as long as they are a part of all the nozzles. In the example shown in FIG. 8B, nozzles 5-3, 5-4 located at the corners of each recording head 3, 4 are selected one by one. The test pattern created in this way is formed on a recording material and read by a reading device installed in the inkjet recording device. The read information of the test chart is sent from the reading device to the control unit 600, where it is image-processed.

The example shown in FIG. 8(b) is a test pattern consisting of a dot pattern in which droplets are ejected from only two nozzles selected one from each of the recording heads 3 and 4, so it is not possible to directly grasp the ejection positions of all nozzles within the overlapping area. However, the relative positional accuracy of the nozzles on each of the recording heads 3 and 4 (the accuracy of the nozzle pitches P1, P2, and P3 on each of the recording heads 3 and 4) is generally very high. Therefore, once the position of at least one nozzle on each of the recording heads 3 and 4 is determined, the positions of all the other nozzles can be estimated with high accuracy.

Therefore, in this example, first, the two dot positions (the ejection positions in the head longitudinal direction of each nozzle corresponding to the dots) of the test chart shown in Figure 8 (b) are measured. Then, the dot positions of the other nozzles are estimated using information on the predetermined nozzle pitch. This makes it possible to identify the dot positions for all nozzles in the overlap region without forming a dot pattern for all nozzles in the overlap region as in the example of Figure 7 (b). Therefore, according to this example, it is possible to set the nozzle switching position while suppressing liquid consumption when forming the test chart.

Next, a method for measuring dot positions by image processing in this embodiment will be described.
9A and 9B are diagrams showing an example of a method for measuring dot positions by image processing.
In the test chart on the recording material described above, isolated dots are formed as shown in Fig. 9(a), and the image read by the reading device is as shown in Fig. 9(b). When identifying the ejection position of each nozzle (the position of the dot in the head longitudinal direction), for example, the center position of the dot may be obtained. In this case, for example, the ejection position of the nozzle can be identified by selecting the peak position of the image density in the head longitudinal direction (pixel showing the peak).

FIG. 10 is a graph plotting image density (pixel value) in the longitudinal direction of the head for the dot portion of the read test chart.
In the example of Fig. 10, the pixel O' with the highest image density can be specified as the dot position (the nozzle ejection position). Also, in the example of Fig. 10, the center of gravity of the pixel values in the entire dot portion can be found, and this center of gravity can be specified as the dot position (the nozzle ejection position). These specification methods are particularly effective when the reading resolution of the reading device is high.

In the example of Figure 10, a spline function is calculated for the pixel values, and the point O where the value obtained by differentiating the curve becomes zero is found, and this point is identified as the dot position (nozzle ejection position). This method of identification is effective when a higher resolution than the reading resolution of the reading device is required.

The above-mentioned test pattern is an example of an isolated dot pattern in which an isolated dot image is formed by liquid ejected from each nozzle, but other patterns are also possible. For example, as shown in FIG. 11(a), it may be a line pattern in which a line-shaped image extending in a direction perpendicular to the head longitudinal direction (the recording material conveyance direction) is formed for each nozzle by liquid ejected multiple times from each nozzle. In this case, too, a read image such as that shown in FIG. 11(b) is obtained, so the dot position (nozzle ejection position) for each nozzle can be identified by the various identification methods described above.

In the example of FIG. 11(b), the widthwise edge of the read line-shaped image can be detected, and the edge position identified from the result can be identified as the ejection position of the corresponding nozzle in the head longitudinal direction. In this case, for example, the position showing a pixel value change exceeding a predetermined threshold can be determined as the edge position of the line-shaped image in the head longitudinal direction. In such a case, it is possible to identify the nozzle ejection position with higher accuracy than an isolated dot.

Next, the rotation correction of the read image will be described.
Due to installation errors of the reading device and conveyance errors of the recording material, for example, the left-right direction on the read image of the test chart may deviate from the direction of the dot rows corresponding to each nozzle row (head longitudinal direction). In this case, the measurement result of the dot position in the left-right direction on the read image may deviate from the measurement result of the nozzle ejection position in the head longitudinal direction, and it may be impossible to set the nozzle switching position appropriately. Therefore, when specifying the nozzle ejection position in the head longitudinal direction with higher accuracy, it is preferable to perform rotation correction of the read image so as to correct the deviation between the left-right direction on the read image of the test chart and the direction of the dot rows corresponding to each nozzle row (head longitudinal direction).

FIG. 12 is a diagram showing an example of a rotation correction chart used for performing rotation correction on a read image.
The rotation correction chart shown in Fig. 12 is formed by creating line images L1 and L2 extending in a direction perpendicular to the head longitudinal direction (the recording material conveyance direction) by liquid ejected multiple times from at least one nozzle of each of the recording heads 3 and 4. This rotation correction chart is formed on the same recording material as the test chart shown in Fig. 7B, but it may be formed on a recording material different from the test chart. In addition, there is no limit to the number of line images of the rotation correction chart, and it may be one or more.

The line images L1, L2 formed in this way are formed to extend parallel to the recording material transport direction. Therefore, in principle, the extension direction of the line images L1, L2 on the read image when read by the reading device matches the vertical direction of the read image. However, if there is an installation error of the reading device or an error in transporting the recording material, the extension direction of the line images L1, L2 on the read image does not match the vertical direction of the read image and is tilted relative to the vertical direction of the read image. In this case, the test chart on the read image will also be tilted relative to the vertical direction (or horizontal direction) of the read image.

In the example of Figure 12, the amount of inclination (tilt angle) between the created line images L1 and L2 and the vertical direction of the read image is measured to determine the amount of rotation of the read image. Then, when measuring the dot positions from the read image of the read test chart, rotation correction is performed using the amount of rotation of the read image determined from the line images L1 and L2, and the dot positions are measured from the read image of the test chart after rotation correction.

FIG. 13 is a diagram showing another example of the rotation correction chart used for performing rotation correction on a read image.
The rotation correction chart shown in Fig. 13 is formed by creating two or more independent images D1 to D4 in a direction perpendicular to the head longitudinal direction (the recording material conveyance direction) by liquid ejected multiple times from at least one nozzle of each of the recording heads 3 and 4. This rotation correction chart is also formed on the same recording material as the test chart shown in Fig. 7B, but it may be formed on a recording material different from that of the test chart. There is no limit to the number of independent images of the rotation correction chart.

The independent images D1, D2 and independent images D3, D4 thus formed are each formed at the same position in the longitudinal direction of the head. Therefore, in the read image read by the reading device, the arrangement direction of these independent images D1, D2 and independent images D3, D4 should normally match the vertical direction of the read image. However, if there is an installation error in the reading device or an error in the transport of the recording material, the arrangement direction of the independent images D1, D2 and independent images D3, D4 on the read image will not match the vertical direction of the read image and will be tilted relative to the vertical direction of the read image. In this case, the test chart on the read image will also be tilted relative to the vertical direction (or horizontal direction) of the read image.

In the example of Figure 13, the amount of rotation of the read image can also be found by measuring the amount of tilt (tilt angle) between the arrangement direction of the created independent images D1, D2 and independent images D3, D4 and the vertical direction of the read image. Then, when measuring the dot positions from the read image of the read test chart, rotation correction is performed using the amount of rotation of the read image found from the independent images D1 to D4, and the dot positions are measured from the read image of the test chart after rotation correction.

Next, another example of the liquid ejecting device according to the present invention will be described with reference to FIGS.
FIG. 14 is an explanatory plan view of the main part of the device, and FIG. 15 is an explanatory side view of the main part of the device.
This device is a serial type device, and a carriage 403 is reciprocated in the main scanning direction by a main scanning movement mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, etc. The guide member 401 is hung between left and right side plates 491A, 491B to movably hold the carriage 403. The carriage 403 is reciprocated in the main scanning direction by the main scanning motor 405 via a timing belt 408 hung between a drive pulley 406 and a driven pulley 407.

This carriage 403 is equipped with a liquid ejection unit 440 that integrates a liquid ejection head device 404 and a head tank 441 according to the present invention. The liquid ejection head device 404 of the liquid ejection unit 440 has a recording unit that ejects liquid of each color, for example, yellow (Y), cyan (C), magenta (M), and black (K), similar to the head unit 2 of the above-mentioned embodiment. In addition, the recording unit of each color in the liquid ejection head device 404 has recording heads 3 and 4 with a nozzle row consisting of multiple nozzles arranged in a staggered pattern, similar to the recording units 2K, 2C, 2M, and 2Y of the above-mentioned embodiment. In addition, the nozzle row direction of each color recording unit is along the sub-scanning direction (head longitudinal direction) perpendicular to the main scanning direction, and the ejection direction is facing downward.

The head tank 441 is supplied with liquid stored in the liquid cartridge 450 by a supply mechanism 494 for supplying liquid stored outside the liquid ejection head device 404 to the liquid ejection head device 404.

The supply mechanism 494 is composed of a cartridge holder 451, which is a filling section in which the liquid cartridge 450 is attached, a tube 456, a liquid delivery unit 452 including a liquid delivery pump, and the like. The liquid cartridge 450 is detachably attached to the cartridge holder 451. Liquid is delivered from the liquid cartridge 450 to the head tank 441 by the liquid delivery unit 452 via the tube 456.

This device is equipped with a transport mechanism 495 for transporting paper 410. The transport mechanism 495 includes a transport belt 412, which is a transport means, and a sub-scanning motor 416 for driving the transport belt 412.

The conveyor belt 412 attracts the paper 410 and conveys it to a position facing the liquid ejection head device 404. The conveyor belt 412 is an endless belt that is stretched between a conveyor roller 413 and a tension roller 414. The paper can be attracted by electrostatic attraction or air suction.

The conveyor belt 412 moves in a circular motion in the sub-scanning direction as the conveyor roller 413 is rotated and driven by the sub-scanning motor 416 via the timing belt 417 and timing pulley 418.

Furthermore, a maintenance and recovery mechanism 420 that maintains and recovers the liquid ejection head device 404 is arranged on one side of the carriage 403 in the main scanning direction, beside the conveyor belt 412.

The maintenance and recovery mechanism 420 is composed of, for example, a cap member 421 that caps the nozzle surface (the surface on which the nozzles are formed) of the liquid ejection head device 404, and a wiper member 422 that wipes the nozzle surface.

The main scanning movement mechanism 493, the supply mechanism 494, the maintenance recovery mechanism 420, and the transport mechanism 495 are attached to a housing including side plates 491A, 491B, and a back plate 491C.

In this device configured in this manner, the paper 410 is fed onto the conveyor belt 412 and adsorbed thereon, and the paper 410 is conveyed in the sub-scanning direction by the circular movement of the conveyor belt 412.

Then, by moving the carriage 403 in the main scanning direction while driving the liquid ejection head device 404 in response to an image signal, liquid is ejected onto the stationary paper 410 to form an image.

As such, this device is equipped with a liquid ejection head according to the present invention, and is therefore capable of stably forming high-quality images.

Next, another example of the liquid discharge unit according to the present invention will be described with reference to FIG.
FIG. 16 is an explanatory plan view of the main part of the unit.

This liquid ejection unit is composed of the components that make up the device that ejects the liquid, including a housing portion made up of side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid ejection head device 404.

It is also possible to configure a liquid ejection unit by further attaching at least one of the aforementioned maintenance and recovery mechanism 420 and supply mechanism 494 to, for example, the side plate 491B of this liquid ejection unit.

Next, still another example of the liquid discharge unit according to the present invention will be described with reference to FIG.
FIG. 17 is a front view of the unit.

This liquid ejection unit is composed of a liquid ejection head device 404 to which a flow path part 444 is attached, and a tube 456 connected to the flow path part 444.

The flow path part 444 is disposed inside the cover 442. A head tank 441 may be included instead of the flow path part 444. A connector 443 is provided on the upper part of the flow path part 444 to electrically connect to the liquid ejection head device 404.

In this application, a "liquid ejection device" is a device that includes a liquid ejection head, a liquid ejection head device, or a liquid ejection unit, and ejects liquid by driving the liquid ejection head. A liquid ejection device includes not only a device that can eject liquid onto an object onto which the liquid can adhere, but also a device that ejects liquid into air or liquid.

This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

For example, examples of "devices that eject liquid" include image forming devices that eject ink to form an image on paper, and three-dimensional modeling devices that eject modeling liquid onto a powder layer formed by layering powder to form a three-dimensional object.

In addition, a "liquid ejecting device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves, and devices that create three-dimensional images.

The above-mentioned "object to which liquid can adhere" means an object to which liquid can adhere at least temporarily, and to which the liquid adheres and sticks, or adheres and penetrates. Specific examples include recording materials such as paper, recording paper, film, and cloth, electronic boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects to which liquid can adhere.

The material "to which liquid can adhere" may be any material to which liquid can adhere even temporarily, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and flooring, and textiles for clothing.

"Liquid" also includes ink, processing liquid, DNA samples, resist, pattern materials, binders, modeling liquids, or solutions and dispersions containing amino acids, proteins, and calcium.

In addition, the "liquid ejection device" may be a device in which a liquid ejection head and an object to which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which the liquid ejection head moves, and a line type device in which the liquid ejection head does not move.

"Devices that eject liquid" include treatment liquid application devices that eject treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and spray granulation devices that spray a composition liquid in which raw materials are dispersed from a nozzle to granulate the raw material into fine particles.

A "liquid ejection unit" is a collection of components related to ejecting liquid, integrating functional parts and mechanisms with a liquid ejection head. For example, a "liquid ejection unit" includes a combination of at least one of the following components with a liquid ejection head: a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, and a main scanning movement mechanism.

Here, integration includes, for example, the liquid ejection head, functional parts, and mechanism being fixed to each other by fastening, bonding, engagement, etc., and one being held movably relative to the other. The liquid ejection head, functional parts, and mechanism may also be configured to be detachable from each other.

For example, some liquid ejection units have a liquid ejection head and a head tank integrated together, such as liquid ejection unit 440 shown in FIG. 15. Others have a liquid ejection head and a head tank integrated together by connecting them together with a tube or the like. Here, a unit including a filter can be added between the head tank and the liquid ejection head of these liquid ejection units.

There are also liquid ejection units in which the liquid ejection head and carriage are integrated.

In some liquid ejection units, the liquid ejection head is movably held by a guide member that constitutes part of the scanning movement mechanism, and the liquid ejection head and the scanning movement mechanism are integrated together. In other liquid ejection units, as shown in FIG. 16, the liquid ejection head, carriage, and main scanning movement mechanism are integrated together.

In some liquid ejection units, a cap member, which is part of the maintenance and recovery mechanism, is fixed to a carriage on which the liquid ejection head is attached, integrating the liquid ejection head, carriage, and maintenance and recovery mechanism.

As shown in Figure 17, there is also a liquid ejection unit in which a tube is connected to a liquid ejection head to which a head tank or flow path components are attached, integrating the liquid ejection head with a supply mechanism.

The main scanning movement mechanism includes the guide member alone. The supply mechanism also includes the tube alone and the loading section alone.

The "liquid ejection head" is not limited to the type of actuator used. For example, in addition to the piezoelectric element (which may use a laminated piezoelectric element) described in the above embodiment, it may also use a thermal actuator that uses an electrothermal conversion element such as a heating resistor, or an electrostatic actuator consisting of a vibration plate and an opposing electrode.

In addition, in this application, the terms image formation, recording, printing, copying, printing, modeling, etc. are all synonymous.

Finally, the above-described embodiments are presented as examples and are not intended to limit the scope of the present invention. Each of the novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Such embodiments and modifications of the embodiments are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents as set forth in the claims.

The above description is merely an example, and each of the following aspects provides unique effects.
[First aspect]
In the first aspect, in a liquid ejection head device (e.g., recording units 2C, 2K, 2M, 2Y) in which two liquid ejection heads (e.g., recording heads 3 and 4) each having a plurality of nozzles 5 arranged thereon are arranged to be shifted in a direction perpendicular to the head longitudinal direction so that the head longitudinal range of the nozzle row in one liquid ejection head (e.g., recording head 3) partially overlaps with the head longitudinal range of the nozzle row in the other liquid ejection head (e.g., recording head 4), the effective nozzles for performing a liquid ejection operation within the overlapping region (e.g., overlap region) are arranged. a setting method for setting a nozzle switching position for switching a nozzle from the nozzles of one liquid ejection head to the nozzles of the other liquid ejection head, the method comprising: a reading step for reading, with a reading device, a first ejection position pattern created by ejecting liquid from the nozzles of the one liquid ejection head and a second ejection position pattern created by ejecting liquid from the nozzles of the other liquid ejection head; and a setting step for setting the nozzle switching position based on the ejection position (e.g., dot position) of each nozzle in the longitudinal direction of the head obtained from each ejection position pattern read in the reading step.
In this embodiment, a first ejection position pattern is created by ejecting liquid from the nozzles of one liquid ejection head, and a second ejection position pattern is created by ejecting liquid from the nozzles of the other liquid ejection head. In this embodiment, these ejection position patterns are read by a reading device, and the nozzle switching position is set based on the ejection position of each nozzle in the head longitudinal direction obtained from each read ejection position pattern. This eliminates the need for an operator to visually set the nozzle switching position, reducing the operator's workload and facilitating the nozzle switching position setting process.

[Second aspect]
The second aspect is characterized in that, in the first aspect, the two liquid ejection heads are provided with a first nozzle group consisting of two or more nozzles arranged so that the nozzle pitch is a first pitch (e.g., narrow pitch P2), and a second nozzle group consisting of two or more nozzles arranged so that the nozzle pitch is a second pitch different from the first pitch (e.g., normal pitch P1 or wide pitch P1), at both ends in the head longitudinal direction, and are arranged so that the head longitudinal range of the first nozzle group of one of the liquid ejection heads overlaps with the head longitudinal range of the second nozzle group of the other liquid ejection head.
This makes it possible to easily obtain nozzles with minimal misalignment in the head longitudinal direction between liquid ejection heads.

[Third aspect]
A third aspect is a nozzle switching position according to the second aspect, characterized in that in the setting step, a nozzle whose ejection position in the head longitudinal direction is located between two adjacent nozzles in one of the first nozzle group and the second nozzle group, which has a narrower nozzle pitch P2, is identified based on the ejection position in the head longitudinal direction of each nozzle (e.g., a dot position) obtained from each ejection position pattern read in the reading step, and the nozzle switching position is set based on the ejection position in the head longitudinal direction of the identified nozzle.
According to this, it is possible to specify the nozzles for which the deviation in position in the head longitudinal direction between the liquid ejection heads is minimal, and it becomes easy to set the nozzle switching position.

[Fourth aspect]
A fourth aspect is characterized in that, in any of the first to third aspects, at least one of the first ejection position pattern and the second ejection position pattern is a pattern created by ejecting liquid from only a portion of the nozzles 5-3, 5-4 arranged in the corresponding liquid ejection head, and in the setting process, the nozzle switching position is set based on the ejection positions in the head longitudinal direction of the portion of the nozzles obtained from each ejection position pattern read in the reading process and the ejection positions in the head longitudinal direction of the other nozzles estimated from the ejection positions in the head longitudinal direction of the portion of the nozzles.
This makes it possible to set the nozzle switching position while suppressing liquid consumption when forming a pattern.

[Fifth aspect]
A fifth aspect is characterized in that, in any of the first to fourth aspects, at least one of the first ejection position pattern and the second ejection position pattern is an isolated dot pattern in which an isolated dot image is formed by liquid ejected from individual nozzles.
This eliminates errors caused by overlapping dots, and makes it possible to specify the ejection position of each nozzle in the longitudinal direction of the head with high accuracy.

[Sixth aspect]
A sixth aspect is characterized in that, in any of the first to fourth aspects, at least one of the first ejection position pattern and the second ejection position pattern is a line pattern in which a line-shaped image extending in a direction perpendicular to the longitudinal direction of the head is formed for each nozzle by liquid ejected multiple times from each individual nozzle.
This makes it possible to more stably and accurately identify the ejection position of each nozzle in the head longitudinal direction.

[Seventh aspect]
A seventh aspect is a nozzle switching position of the sixth aspect, characterized in that in the setting process, the ejection position in the head longitudinal direction of the corresponding nozzle is determined based on the result of detecting the widthwise edges of each line-shaped image in the line pattern read in the reading process.
This makes it possible to easily identify the ejection position of each nozzle in the longitudinal direction of the head.

[Eighth aspect]
The eighth aspect is characterized in that, in any of the first to seventh aspects, at least one of the first ejection position pattern and the second ejection position pattern includes an ejection position pattern created by ejecting liquid from one nozzle multiple times.
This makes it possible to identify the ejection position of each nozzle in the longitudinal direction of the head with high accuracy.

[Ninth aspect]
A ninth aspect is a method according to any one of the first to eighth aspects, which includes a slope determination step of creating line images L1, L2 extending in a direction perpendicular to the longitudinal direction of the head by liquid ejected multiple times from at least one nozzle, reading the line images by the reading device, and determining the slope of the first ejection position pattern and the second ejection position pattern from the slope of the read line image, and further comprising a setting step of setting the nozzle switching position based also on the slope determined in the slope determination step.
This makes it possible to correct errors due to installation errors of the reading device, errors in conveying the recording material, and the like, and to specify the ejection position of each nozzle in the longitudinal direction of the head with high accuracy.

[Tenth Aspect]
A tenth aspect is a method according to any one of the first to eighth aspects, which includes a slope determination step of creating two or more independent images in a direction perpendicular to the longitudinal direction of the head by using liquid ejected multiple times from at least one nozzle, reading the images with the reading device, and determining the slope of the first ejection position pattern and the second ejection position pattern from the amount of positional deviation in the longitudinal direction of the head in the two or more read independent images, and wherein the setting step sets the nozzle switching position based also on the slope determined in the slope determination step.
This makes it possible to correct errors due to installation errors of the reading device, errors in conveying the recording material, and the like, and to specify the ejection position of each nozzle in the longitudinal direction of the head with high accuracy.

[Eleventh aspect]
An eleventh aspect is a liquid ejection head device (e.g., recording heads 3 and 4), each having a plurality of nozzles arranged therein, in which two liquid ejection heads are arranged offset in a direction perpendicular to the head longitudinal direction so that the head longitudinal range of the nozzle row in one liquid ejection head partially overlaps with the head longitudinal range of the nozzle row in the other liquid ejection head, and a nozzle switching position is set for switching effective nozzles that perform liquid ejection operations within the overlapping overlap area from the nozzles of one liquid ejection head to the nozzles of the other liquid ejection head, wherein the nozzle switching position is set based on the ejection position of each nozzle in the head longitudinal direction obtained by reading with a reading device a first ejection position pattern created by ejecting liquid from the nozzles of one of the liquid ejection heads and a second ejection position pattern created by ejecting liquid from the nozzles of the other liquid ejection head.
According to this, the operation of setting the nozzle switching position becomes easy, so that a liquid ejection head device can be provided with reduced manufacturing costs.

[Twelfth aspect]
A twelfth aspect is a liquid ejection unit, characterized in that it includes the liquid ejection head device of the eleventh aspect.
According to this, the operation of setting the nozzle switching position becomes easy, so that a liquid ejection unit can be provided with reduced manufacturing costs.

[Thirteenth aspect]
A thirteenth aspect is a device for discharging liquid, characterized in that it comprises the liquid discharge head device of the eleventh aspect or the liquid discharge unit of the twelfth aspect.
According to this, the operation of setting the nozzle switching position becomes easy, so that it is possible to provide a liquid ejecting device with reduced manufacturing costs.

[14th aspect]
A fourteenth aspect is a program executed by a computer for setting a nozzle switching position of a liquid ejection head device in which two liquid ejection heads, each having a plurality of nozzles arranged therein, are arranged with the two liquid ejection heads shifted in a direction perpendicular to the head longitudinal direction so that the head longitudinal range of the nozzle row of one liquid ejection head partially overlaps with the head longitudinal range of the nozzle row of the other liquid ejection head, and a nozzle switching position is set for switching effective nozzles that perform liquid ejection operations within the overlapping overlap area from the nozzles of one liquid ejection head to the nozzles of the other liquid ejection head, the program being characterized in that the program causes the computer to execute a reading process of reading with a reading device a first ejection position pattern created by ejecting liquid from the nozzles of one liquid ejection head and a second ejection position pattern created by ejecting liquid from the nozzles of the other liquid ejection head, and a setting process of setting the nozzle switching position based on the head longitudinal ejection position of each nozzle obtained from each ejection position pattern read in the reading process.
According to this, since it is not necessary for the operator to visually set the nozzle switching position, the workload on the operator can be reduced and the operation of setting the nozzle switching position becomes easier.

1: Inkjet recording device 2: Head units 2C, 2K, 2M, 2Y: Recording section 3: Recording head 4: Recording head 5: Nozzle 20: Head driving section 21: Drive waveform correction section 22: Head control section 23: Basic drive waveform generating section 24: Drive waveform correction information storage section 401: Guide member 403: Carriage 404: Liquid ejection head device 405: Main scanning motor 406: Drive pulley 407: Driven pulley 408: Timing belt 410: Paper 412: Conveyor belt 413: Conveyor roller 414: Tension roller 416: Sub-scanning motor 417: Timing belt 418: Timing pulley 420: Maintenance recovery mechanism 421: Cap member 422: Wiper member 440: Liquid ejection unit 441: Head tank 442: Cover 443: Connector 444: Flow path part 450 : Liquid cartridge 451 : Cartridge holder 452 : Liquid delivery unit 456 : Tube 491A : Side plate 491B : Side plate 491C : Back plate 493 : Main scanning movement mechanism 494 : Supply mechanism 495 : Transport mechanism 600 : Control unit 610 : CPU
620: Storage unit 630: RAM
640: ROM
710: Transport drive unit 720: Operation display unit 730: Input/output interface 740: Bus line 800: External device

JP 2000-190484 A

Claims (14)

A liquid ejection head device in which two liquid ejection heads, each having a plurality of nozzles arranged therein, are arranged to be shifted in a direction perpendicular to a head longitudinal direction so that a head longitudinal range of a nozzle row in one of the liquid ejection heads partially overlaps with a head longitudinal range of a nozzle row in the other liquid ejection head, the method comprising: setting a nozzle switching position for switching effective nozzles that perform liquid ejection within the overlapping area from the nozzles of one liquid ejection head to the nozzles of the other liquid ejection head, the method comprising:
a reading step of reading, by a reading device, a first ejection position pattern created by ejecting liquid from the nozzles of the one liquid ejection head and a second ejection position pattern created by ejecting liquid from the nozzles of the other liquid ejection head;
a setting step of setting the nozzle switching position based on the ejection position of each nozzle in the head longitudinal direction obtained from each ejection position pattern read in the reading step ;
a gradient specifying step of creating a line image extending in a direction perpendicular to the longitudinal direction of the head by liquid ejected multiple times from at least one nozzle, reading the line image by the reading device, and specifying gradients of the first ejection position pattern and the second ejection position pattern from the gradient of the read line image ,
The nozzle switching position setting method is characterized in that in the setting step, the nozzle switching position is set based on the inclination identified in the inclination identification step . A liquid ejection head device in which two liquid ejection heads, each having a plurality of nozzles arranged therein, are arranged to be shifted in a direction perpendicular to a head longitudinal direction so that a head longitudinal range of a nozzle row in one of the liquid ejection heads partially overlaps with a head longitudinal range of a nozzle row in the other liquid ejection head, the method comprising: setting a nozzle switching position for switching effective nozzles that perform liquid ejection within the overlapping area from the nozzles of one liquid ejection head to the nozzles of the other liquid ejection head, the method comprising:
a reading step of reading, by a reading device, a first ejection position pattern created by ejecting liquid from the nozzles of the one liquid ejection head and a second ejection position pattern created by ejecting liquid from the nozzles of the other liquid ejection head;
a setting step of setting the nozzle switching position based on the ejection position of each nozzle in the head longitudinal direction obtained from each ejection position pattern read in the reading step;
a gradient specifying step of creating two or more independent images in a direction perpendicular to the head longitudinal direction by using liquid ejected multiple times from at least one nozzle, reading the images with the reading device, and specifying gradients of the first ejection position pattern and the second ejection position pattern from a positional deviation amount in the head longitudinal direction in the two or more independent images that have been read,
The nozzle switching position setting method is characterized in that in the setting step, the nozzle switching position is set based on the inclination identified in the inclination identification step. 3. The method for setting a nozzle switching position according to claim 1,
The two liquid ejection heads are provided with a first nozzle group consisting of two or more nozzles arranged so that the nozzle pitch is a first pitch, and a second nozzle group consisting of two or more nozzles arranged so that the nozzle pitch is a second pitch different from the first pitch, at both ends of the head in the longitudinal direction, and are arranged so that the head longitudinal range of the first nozzle group of one of the liquid ejection heads overlaps with the head longitudinal range of the second nozzle group of the other liquid ejection head. 4. The method for setting a nozzle switching position according to claim 3 ,
The setting process includes identifying a nozzle from one of the first and second nozzle groups, which has a narrower nozzle pitch, based on the ejection position in the longitudinal direction of the head of each nozzle obtained from each ejection position pattern read in the reading process, and setting the nozzle switching position based on the ejection position in the longitudinal direction of the head of the identified nozzle from the other nozzle group, which has a wider nozzle pitch. 5. The method for setting a nozzle switching position according to claim 1,
At least one of the first ejection position pattern and the second ejection position pattern is a pattern created by ejecting liquid from only some of the nozzles arranged in a corresponding liquid ejection head,
A method for setting a nozzle switching position, characterized in that in the setting process, the nozzle switching position is set based on the ejection positions in the longitudinal direction of the head of some of the nozzles obtained from each ejection position pattern read in the reading process, and the ejection positions in the longitudinal direction of the head of other nozzles estimated from the ejection positions in the longitudinal direction of the head of some of the nozzles. The method for setting a nozzle switching position according to any one of claims 1 to 5 ,
A method for setting a nozzle switching position, characterized in that at least one of the first ejection position pattern and the second ejection position pattern is an isolated dot pattern in which an isolated dot image is formed by liquid ejected from each nozzle. The method for setting a nozzle switching position according to any one of claims 1 to 5 ,
a nozzle switching position setting method, characterized in that at least one of the first ejection position pattern and the second ejection position pattern is a line pattern in which a line-shaped image extending in a direction perpendicular to the longitudinal direction of the head is formed for each nozzle by liquid ejected multiple times from each individual nozzle. 8. The method for setting a nozzle switching position according to claim 7 ,
A method for setting a nozzle switching position, characterized in that in the setting process, the ejection position in the longitudinal direction of the head of the corresponding nozzle is determined based on the results of detecting the widthwise edges of each line-shaped image in the line pattern read in the reading process. 9. The method for setting a nozzle switching position according to claim 1,
The method for setting a nozzle switching position, wherein at least one of the first ejection position pattern and the second ejection position pattern includes an ejection position pattern created by ejecting liquid from one nozzle a plurality of times . two liquid ejection heads, each having a plurality of nozzles arranged therein, are arranged to be shifted in a direction perpendicular to the head longitudinal direction such that a range in the head longitudinal direction of a nozzle row in one liquid ejection head partially overlaps a range in the head longitudinal direction of a nozzle row in the other liquid ejection head;
a liquid ejection head device in which a nozzle switching position is set for switching effective nozzles for ejecting liquid within the overlapping region from the nozzles of one of the liquid ejection heads to the nozzles of the other liquid ejection head,
The liquid ejection head device is characterized in that the nozzle switching position is set based on the ejection position of each nozzle in the longitudinal direction of the head obtained by reading with a reading device a first ejection position pattern created by ejecting liquid from the nozzles of one of the liquid ejection heads and a second ejection position pattern created by ejecting liquid from the nozzles of the other liquid ejection head, and on the inclination of the first ejection position pattern and the second ejection position pattern determined from the inclination of the read line image created by ejecting liquid multiple times from at least one nozzle and reading it with the reading device. two liquid ejection heads, each having a plurality of nozzles arranged therein, are arranged to be shifted in a direction perpendicular to the head longitudinal direction such that a range in the head longitudinal direction of a nozzle row in one liquid ejection head partially overlaps a range in the head longitudinal direction of a nozzle row in the other liquid ejection head;
a liquid ejection head device in which a nozzle switching position is set for switching effective nozzles for ejecting liquid within the overlapping region from the nozzles of one of the liquid ejection heads to the nozzles of the other liquid ejection head,
a nozzle switching position determining section for determining a position of the nozzle in the longitudinal direction of the head by reading, with a reading device, a first ejection position pattern created by ejecting liquid from a nozzle of one of the liquid ejection heads and a second ejection position pattern created by ejecting liquid from a nozzle of the other liquid ejection head; and a tilt of the first ejection position pattern and the second ejection position pattern determined from the amount of positional deviation in the longitudinal direction of the head in the two or more independent images that are read by the reading device, the tilt of the first ejection position pattern and the second ejection position pattern being .... A liquid ejection unit comprising the liquid ejection head device according to claim 10 or 11 . two liquid ejection heads, each having a plurality of nozzles arranged therein, are arranged to be shifted in a direction perpendicular to the head longitudinal direction such that a range in the head longitudinal direction of a nozzle row in one liquid ejection head partially overlaps a range in the head longitudinal direction of a nozzle row in the other liquid ejection head;
a nozzle switching position for switching effective nozzles for performing a liquid ejection operation within the overlapping area from the nozzles of one liquid ejection head to the nozzles of the other liquid ejection head, the nozzle switching position being set, the program being executed by a computer to set the nozzle switching position of a liquid ejection head device,
a reading step of reading, by a reading device, a first ejection position pattern created by ejecting liquid from the nozzles of the one liquid ejection head and a second ejection position pattern created by ejecting liquid from the nozzles of the other liquid ejection head;
a setting step of setting the nozzle switching position based on the ejection position of each nozzle in the head longitudinal direction obtained from each ejection position pattern read in the reading step ;
a gradient specifying step of creating a line image extending in a direction perpendicular to a longitudinal direction of the head by using liquid ejected multiple times from at least one nozzle, reading the line image with the reading device, and specifying gradients of the first ejection position pattern and the second ejection position pattern from the gradient of the read line image ,
The setting step sets the nozzle switching position based on the inclination identified in the inclination identification step . two liquid ejection heads, each having a plurality of nozzles arranged therein, are arranged to be shifted in a direction perpendicular to the head longitudinal direction such that a range in the head longitudinal direction of a nozzle row in one liquid ejection head partially overlaps a range in the head longitudinal direction of a nozzle row in the other liquid ejection head;
a nozzle switching position for switching effective nozzles for performing a liquid ejection operation within the overlapping area from the nozzles of one liquid ejection head to the nozzles of the other liquid ejection head, the nozzle switching position being set, the program being executed by a computer to set the nozzle switching position of a liquid ejection head device,
a reading step of reading, by a reading device, a first ejection position pattern created by ejecting liquid from the nozzles of the one liquid ejection head and a second ejection position pattern created by ejecting liquid from the nozzles of the other liquid ejection head;
a setting step of setting the nozzle switching position based on the ejection position of each nozzle in the head longitudinal direction obtained from each ejection position pattern read in the reading step;
a gradient specifying step of creating two or more independent images in a direction perpendicular to the head longitudinal direction by using liquid ejected multiple times from at least one nozzle, reading the images with the reading device, and specifying gradients of the first ejection position pattern and the second ejection position pattern from a positional deviation amount in the head longitudinal direction in the two or more read independent images,
The setting step sets the nozzle switching position based on the inclination identified in the inclination identification step.

Images