LIQUID EJECTION HEAD DEVICE, LIQUID EJECTION UNIT, DEVICE FOR EJECTION OF LIQUID, AND PROGRAM

Abstract

To provide a liquid discharge head device, liquid discharge unit, device for discharging liquid and program which can excellently suppress a pitch shift at a nozzle switching position.SOLUTION: A nozzle switching position for switching an effective nozzle that performs a liquid discharge operation in an overlapping region where a portion of a nozzle array of one liquid discharge head of the two liquid discharge heads overlaps a portion of the nozzle array of the other liquid discharge head from the nozzle of the one liquid discharge head to the nozzle of the other liquid discharge head is set to a nozzle position where a difference between the impact position Xc (A,βch) of the one liquid discharge head and the impact position Xc (B,βch) of the other liquid discharge head calculated in consideration of a discharge bend amount (θ(α,βch)) of the liquid discharged from the nozzle due to the autogenous airflow or the like becomes minimum.SELECTED DRAWING: Figure 17

Description

Technical Field

[0001] The present invention relates to a liquid ejection head device, a liquid ejection unit, a device for ejecting a liquid, and a program.

Background Art

[0002] Conventionally, a liquid ejection head device has been known in which a nozzle row in one of two liquid ejection heads in each of which a plurality of nozzles are arranged is arranged so as to partially overlap with a nozzle row in the other liquid ejection head.

[0003] 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 this Patent Document 1, in the recording inspection process after assembling this line recording head, a nozzle switching position for switching effective nozzles for performing a liquid ejection operation in the overlapping region between one recording head and the other recording head from the nozzles of one recording head to the nozzles of the other recording head is set. Specifically, dot recording is performed on a recording material (recording material) while shifting the nozzle switching position one by one, and the nozzle switching position is set when the switching point between one recording head and the other recording head cannot be visually distinguished by an operator. According to this, even if high-precision alignment is not performed between the recording heads, recording unevenness due to landing pitch deviation at the nozzle switching position is suppressed.

Summary of the Invention

Problems to be Solved by the Invention

[0004] There was room for improvement in the landing pitch deviation at the nozzle switching position.

Means for Solving the Problems

[0005] In order to solve the above-described problems, the present invention arranges two liquid ejection heads each having a plurality of nozzles such that the head longitudinal direction range of the nozzle row in one of the liquid ejection heads partially overlaps with the head longitudinal direction range of the nozzle row in the other liquid ejection head, and the two liquid ejection heads are arranged with a shift in a direction orthogonal to the head longitudinal direction. A liquid ejection head device that sets a nozzle switching position for switching effective nozzles that perform a liquid ejection operation within the partially overlapping region from the nozzles of one liquid ejection head to the nozzles of the other liquid ejection head, wherein the nozzle switching position satisfies the relationship of the following formula 1 for the landing position (XcA, βch) of each nozzle in the overlapping region of one liquid ejection head A, and the landing position (Xc(B, βch)) of each nozzle in the overlapping region of the other liquid ejection head B that satisfies the relationship of the following formula 1, and is the nozzle position where the difference |Xc(B, βch) - Xc(A, βch)| is minimized. When the distance d between the nozzle and the ejection target is changed, set the nozzle switching position It is characterized by this. Xc(α,βch) =Xn(α,βch)+d×tanθ(α,βch)···(Formula 1) α: Label (A or B) for identifying one liquid ejection head A and the other liquid ejection head B β: Nozzle number starting from one end side in the head longitudinal direction (1, 2, ···, N (N = number of nozzles in the overlapping region)) θ(α,βch): Discharge bending amount of each nozzle in the overlapping region Xn(α,βch): Position in the head longitudinal direction of each nozzle in the overlapping region d: Distance between the nozzle and the ejection target

Effect of the Invention

[0006] According to the present invention, it is possible to favorably suppress the landing pitch deviation at the nozzle switching position.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

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Figure 8

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Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

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Figure 20

Figure 21

Figure 22

Figure 23

Embodiments for Carrying Out the Invention

[0008] Hereinafter, an embodiment in which the liquid discharge head according to the present invention is applied to a head unit which is a liquid discharge unit including a liquid discharge head device of an inkjet recording device as an apparatus for discharging a liquid will be described.

[0009] First, the head unit in the present embodiment will be described. FIG. 1 is a plan view of the head unit 4 as viewed from the normal direction of the recording material P0. The recording material P0 is, for example, paper, and may be roll paper (continuous paper) or cut paper, etc. Also, various media other than paper may be used. The recording material P0 is conveyed along the conveyance direction indicated by the arrow in FIG. 1. The head unit 4 is supported so as to face the recording surface of the recording material P0 at a predetermined distance.

[0010] The head unit 4 includes a K recording unit 2K, a C recording unit 2C, an M recording unit 2M, and a Y recording unit 2Y as liquid discharge head devices for each color provided corresponding to each ink (liquid) of black (K), cyan (C), magenta (M), and yellow (Y). That is, the head unit 4 is configured by combining four liquid discharge head devices.

[0011] As shown in FIG. 1, in each of the color recording units 2K, 2C, 2M, and 2Y, recording heads 3A and 3B as liquid ejection heads are arranged in a staggered manner along the width direction of the recording material (the direction orthogonal to the conveyance direction), which is the head width direction. In the present embodiment, for the sake of explanation, the even-numbered recording heads counted from the left side in FIG. 1 are regarded as one recording head 3A, and the odd-numbered recording heads are regarded as the other recording head 3B for explanation. However, there is no difference in the configuration and function between one recording head 3A and the other recording head 3B.

[0012] The head unit 4 ejects ink droplets from the nozzles of each of the color recording units 2K, 2C, 2M, and 2Y in synchronization with the position of the recording material being conveyed, thereby forming a color image on the recording material P0. Note that the number of recording units mounted on the head unit 4, the number of recording heads arranged in the recording unit, the color of the ink ejected from the recording unit, etc. can be arbitrarily set. Therefore, for example, the head unit 4 may be a head unit that includes only the black single-color recording unit 2K and performs recording in black single color.

[0013] FIG. 2 is an explanatory diagram showing the head arrangement of one recording head 3A and the other recording head 3B provided for each recording unit of the head unit 4. One recording head 3A and the other recording head 3B each have a nozzle row in which a plurality of nozzles 5 are arranged along the head width direction. In the present embodiment, an example in which the nozzle row is one row will be described, but a configuration in which two or more nozzle rows are arranged side by side in the recording material conveyance direction may also be used. Further, the nozzle row may be arranged such that the direction of the nozzle row is inclined with respect to the head width direction.

[0014] Also, as shown in FIG. 2, on one recording unit of the present embodiment, one of the two recording heads 3A and 3B arranged adjacent to each other along the head width direction is arranged so as to partially overlap (overlap) the other recording head 3B. By arranging the recording heads 3A and 3B in this way, the recording range in the head width direction of the entire recording unit (the range where an image can be recorded by the ink ejected from the nozzles 5) can be expanded. As a result, a recording unit having a recording range over the width direction of the recording material P0 can be obtained, and a line type head unit 4 can be realized. Therefore, an image can be formed on the recording material P0 in one pass without scanning the head unit 4.

[0015] FIG. 3 is an explanatory diagram showing the relationship of the nozzle pitches of two recording heads 3A and 3B arranged adjacent to each other along the head width direction. FIG. 3(a) shows that the nozzle rows provided in the recording heads 3A and 3B include 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 nozzle pitch P2 narrower than the normal pitch P1. Most of the nozzle row is in the normal region, but the narrow region is provided only on one end side of the nozzle row. 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 adopted.

[0016] Also, in the configuration of FIG. 3(a), both the normal pitch P1 and the narrow nozzle pitch P2 are set to be the same pitch between the recording head 3A and the recording head 3B. Therefore, as the recording head 3A and the recording head 3B, those having the same configuration can be used for each other. Therefore, the recording unit can be manufactured by preparing only one type of recording head, and the manufacturing cost can be reduced as compared with the case where the recording heads 3A and 3B have different configurations.

[0017] Further, as shown in FIG. 3(b), the nozzle arrays provided in the recording heads 3A and 3B may be composed of a normal region with a normal pitch P1, a narrow region with a nozzle pitch narrower than the normal pitch, and a wide region with a nozzle pitch wider than the normal pitch. In FIG. 3(b), one end side (left side in the figure) in the recording material width direction of the recording heads 3A and 3B is a wide region, and the other end side (right side in the figure) in the recording material width direction is a narrow region. In the overlap region between the recording head 3A and the recording head 3B, one recording head 3A is a wide region and the other recording head 3B is a narrow region.

[0018] Thus, in the present embodiment, in the overlap region between one recording head 3A and the other recording head 3B, the nozzle pitch of one recording head 3A and the nozzle pitch of the other recording head 3B are configured to be different.

[0019] FIG. 4 is a block diagram showing the hardware configuration of the control system of the inkjet recording apparatus 1 equipped with the above-described head unit 4. In addition to the above-described head unit 4, the inkjet recording apparatus 1 is configured such that a control unit 600, a conveyance drive unit 710, an operation display unit 720, and an input / output interface 730 are interconnected via a bus line 740.

[0020] The head unit 4 is provided with a head drive unit 20 that drives the recording heads 3A and 3B disposed in the recording units 2K, 2C, 2M, and 2Y of each color. The head drive unit 20 generates a drive waveform for deforming and operating each piezoelectric element, which is an electromechanical conversion element serving as an actuator in each of the recording heads 3A and 3B of each of the recording units 2K, 2C, 2M, and 2Y, in accordance with a control signal input from the control unit 600. When this drive waveform is input to each piezoelectric element of each of the recording heads 3A and 3B of each of the recording units 2K, 2C, 2M, and 2Y, the liquid in the pressure chamber communicating with the nozzle 5 is pressurized and ejection energy is applied, and ink is ejected from the corresponding nozzle 5.

[0021] The control unit 600 includes 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 various control programs and setting data stored in the ROM 640, stores them in the RAM 630, and executes them to perform various arithmetic processes. Further, the CPU 610 controls the overall operation of the inkjet recording apparatus 1. As will be described later, the ROM 640 stores a nozzle switching position setting program for setting the nozzle switching position between one recording head 3A and the other recording head 3B.

[0022] The storage unit 620 stores a print job (image recording instruction) and print image data (image information) input via the input / output interface 730. Further, the storage unit 620 stores a discharge bending amount θ, which is the amount of bending of ink droplets ejected from each nozzle, and a calculation formula for calculating the landing position of the ink droplets ejected from the nozzle on the recording material. Also stored are the nozzle switching positions set based on the landing positions calculated by the calculation.

[0023] The conveyance drive unit 710 supplies a drive signal to the conveyance motor based on a control signal supplied from the control unit 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 an operation key and a touch panel arranged to overlap the screen of the display device. The operation display unit 720 causes the display device to display various information, and supplies an operation signal corresponding to a user's input operation on the input device to the control unit 600. 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.

[0024] FIG. 5 is a block diagram showing the hardware configuration of the head drive unit 20 of the head unit 4. In FIG. 5, for simplicity of the figure, only one recording head 3A is shown, and the other recording heads are omitted.

[0025] The head drive unit 20 includes drive waveform correction units 21-1 to 21-n corresponding to each of the nozzles 5-1 to 5-n (where "n" is the number of nozzles on the recording head 3A) on the recording head 3A. The head drive unit 20 also includes a head control unit 22, a basic drive waveform generation unit 23, and a drive waveform correction information holding unit 24.

[0026] The head control unit 22 converts the image data input from the control unit 600 into control signals for each of the nozzles 5-1 to 5-n of each of the recording heads 3A and 3B of the respective recording units 2K, 2C, 2M, and 2Y. Based on the 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, the conveyance speed, and the printing environment such as temperature and humidity. The drive waveform correction information holding unit 24 stores information indicating the nozzle numbers of the nozzles that require correction and information indicating the correction amounts.

[0027] 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 holding unit 24, and supply the corrected drive voltage to the respective piezoelectric elements corresponding to the nozzles 5-1 to 5-n. As a result, different ejection characteristics can be given to the nozzles 5-1 to 5-n individually, and appropriate ink ejection can be achieved from each of the nozzles 5-1 to 5-n.

[0028] In this embodiment, different ejection characteristics are given for each nozzle, but it is not limited thereto. That is, ejection characteristics may be given for each nozzle row, or ejection characteristics may be given for each region with different pitches. Which unit to give the ejection characteristics can be determined according to constraints such as the memory of the apparatus and the load of the applied voltage.

[0029] FIG. 6 is a diagram for explaining the setting of the nozzle switching position between one recording head 3A and the other recording head 3B. FIG. 6(b) shows the landing positions of the ink droplets ejected from the nozzles of one recording head 3A and the other recording head 3B on the recording material. The black dots in the lower part of the figure indicate the landing positions of the ink of the recording head 3A, and the dots in the upper part of the figure indicate the landing positions of the ink of the recording head 3B.

[0030] As shown in FIG. 6(b), the nozzle at which the difference ΔC (hereinafter referred to as the landing position deviation) between the landing position of the recording head 3B and the landing position of the recording head 3A becomes the minimum is set as the nozzle switching position (arrow E in the figure). For the nozzles in the regions T3 and T4 on the end side (the recording head 3B is on the left side in the figure, and the recording head 3A is on the right side in the figure) from the set nozzle switching position, the driving is stopped.

[0031] FIG. 6(c) shows the landing positions of the ink ejected onto the recording material when each recording head is driven and controlled at the set nozzle switching position. As shown in FIG. 6(c), ink droplets are ejected from the nozzles of one recording head 3A in the region on the left side in the figure from the nozzle switching position. Ink droplets are ejected from the nozzles of the other recording head 3B in the region on the right side in the figure from the nozzle switching position.

[0032] When the setting of the nozzle switching position is set as follows, there is a possibility that the landing pitch becomes large at the nozzle switching position, and the printing streaks where the background of the recording material is exposed vertically in the image on the recording material become conspicuous. That is, it is the case where the nozzle with the minimum deviation in the recording material width direction position between one recording head 3A and the other recording head 3B is specified, and the specified nozzle is set as the nozzle switching position.

[0033] Generally, when ink is ejected from a recording head, a self-airflow is generated. Due to this self-airflow, the ink droplets ejected from the nozzles do not eject parallel to the direction perpendicular to the nozzle surface, but bend with respect to the direction perpendicular to the nozzle surface. As a result, due to the influence of the self-airflow, even if the nozzle with the minimum displacement in the width direction between the nozzles of one recording head 3A and the nozzles of the other recording head 3B is set as the nozzle switching position, the landing droplet pitch becomes large at the nozzle switching position. Thereby, there were cases where print streaks with the ground texture of the recording material exposed were conspicuous in the image on the recording material.

[0034] Therefore, in the present embodiment, the setting of the nozzle switching position is performed in consideration of the amount of bending of the ink droplets due to the self-airflow (hereinafter referred to as the ejection bending amount θ). Hereinafter, it will be specifically described with reference to the drawings. In the following description, the width direction of the recording material (the longitudinal direction of the recording head) is defined as the X direction, the conveyance direction of the recording material (the short-side direction of the recording head) is defined as the Y direction, and the direction perpendicular to the nozzle surface is defined as the Z direction. The origin in the X direction is one end in the width direction of the nozzle surface, and the origin in the Y direction is the upstream end in the recording material conveyance direction of the nozzle surface. Also, the origin in the Z direction is the nozzle surface. Also, in the following description, for the sake of simplification, factors that cause ejection bending other than the self-airflow are ignored, and it is assumed that there is no positional deviation of the nozzles from the design drawing.

[0035] FIG. 7 is a schematic diagram showing the ejection direction of the ink droplets S ejected from each nozzle 5 of the recording head. As shown in FIG. 7, generally, when ink droplets S are ejected simultaneously from a plurality of nozzles 5 of the recording head, the ink droplets ejected from the nozzles 5 on the end side of the recording head due to the self-airflow generated during ejection often bend significantly inward in the X direction. The absolute value of the ejection bending amount becomes larger toward the end side of the recording head.

[0036] FIG. 8 is a diagram for explaining the ejection bending amount θ. In this embodiment, as shown in FIG. 8, the angle formed by the Z direction (the direction perpendicular to the nozzle surface (XY plane)) and the ejection direction of the ink droplet S is defined as the ejection deflection amount θ. When the ejection deflection amount θ is positive, it indicates that the ink droplet S is ejected from the nozzle 5 toward the positive side in the X-axis direction (the other end side in the width direction), and when the ejection deflection amount θ is negative, it indicates that the ink droplet S is ejected from the nozzle 5 toward the negative side in the X-axis direction (one end side in the width direction).

[0037] FIG. 9 is a graph showing an example of the ejection deflection amount θ of each nozzle of the recording head. Note that the horizontal axis shown in FIG. 9 indicates the nozzle number, with the nozzle number at one end in the width direction being 1 [ch] and the nozzle number at the other end in the width direction being n [ch] (n = the number of nozzles of the recording head).

[0038] As shown in FIG. 9, the ink droplets ejected from the nozzle (1 [ch]) at one end in the width direction are greatly deflected in the +X direction, and the ink droplets ejected from the nozzle (n [ch]) at the other end in the width direction are greatly deflected in the -X direction. On the other hand, it can be seen that the ink droplets ejected from the nozzles near the center in the width direction are hardly deflected.

[0039] FIG. 10 is a diagram for explaining the ejection deflection amount θ of each nozzle in the overlap region between one recording head 3A and the other recording head 3B. The overlap region where one recording head 3A overlaps with the other recording head 3B is the other end side in the width direction of the recording head 3A. Therefore, the ink droplets ejected from the nozzles in the overlap region of one recording head 3A (hereinafter referred to as the Vernier nozzles) are deflected in the -X direction by the self-airflow. On the other hand, the overlap region where the other recording head 3B overlaps with one recording head 3A is the one end side in the width direction of the recording head 3B. Therefore, the ink droplets ejected from the Vernier nozzles of the other recording head 3B are deflected in the +X direction. In this way, the deflection directions of the ink droplets ejected from the Vernier nozzles of one recording head 3A and the deflection directions of the ink droplets ejected from the Vernier nozzles of the other recording head 3B are different from each other.

[0040] Hereinafter, a specific example of this embodiment will be described. FIG. 11 is a diagram for explaining the nozzles (barrier nozzles) in the overlap region of each recording head 3A and 3B of this embodiment. In this embodiment, the number N of the barrier nozzles of each recording head 3A and 3B is 50. The barrier nozzles of one recording head 3A are (A, 1ch), (A, 2ch), (A, 3ch) ··· (A, N = 50ch) from one end side in the width direction. Also, the coordinates (X-direction position) of each barrier nozzle of one recording head 3A are set as Xn(A, βch). However, β is the nozzle number (1ch, 2ch ··· Nch) of the barrier nozzle. Further, the coordinates (position in the X direction) of the landing position of the ink droplets ejected from each barrier nozzle of one recording head 3A are set as Xc(A, βch).

[0041] The barrier nozzles of the other recording head 3B are (B, 1ch), (B, 2ch), (B, 3ch) ··· (B, N = 50ch) from one end side in the width direction. Also, the coordinates of each barrier nozzle of the other recording head 3B are set as Xn(B, βch). Further, the coordinates of the landing position of the ink droplets ejected from each barrier nozzle of the other recording head 3B are set as Xc(B, βch).

[0042] Also, in this embodiment, the nozzle pitch of the barrier nozzles of one recording head 3A is set as a nozzle pitch P3 = (P1 + Δ) wider than the nozzle pitch (normal pitch P1) in the normal region. Also, the nozzle pitch of the barrier nozzles of the other recording head 3B is set as a nozzle pitch P2 = (P1 - Δ) narrower than the normal pitch P1.

[0043] In this embodiment, the normal pitch P1 is set to 42.33 [μm] (600 dpi), the nozzle pitch P3 of the burner nozzles of one recording head 3A is set to 42.33 + 0.55 = 42.88 [μm], and the nozzle pitch P2 of the burner nozzles of the other recording head 3B is set to 42.33 - 0.55 = 41.78 [μm]. Also, the distance d from the nozzle surface to the recording material is set to 1.3 [mm]. In this embodiment, the number N of burner nozzles is set to 50, but generally, the number N of burner nozzles is determined in consideration of the pitch of the burner nozzles, the required accuracy of the coordinates of each recording head, the allowable landing deviation, etc.

[0044] Here, it is assumed that the first burner nozzle (B, 1ch) of the other recording head 3B is displaced by +10 μm in the X direction with respect to the first burner nozzle (A, 1ch) of one recording head 3A. That is, Xn(B, 1ch) - Xn(A, 1ch) = 10 [μm]. Regarding this case, the setting of the switching position without considering the ejection deflection amount θ (hereinafter referred to as the reference example) and the setting of the nozzle switching position of this embodiment will be described.

[0045] First, the setting of the nozzle switching position in the reference example without considering the ejection deflection amount θ will be described. FIG. 12 is a graph plotting the coordinate difference (|Xn(B, βch) - Xn(A, βch)|) between the burner nozzles of one recording head 3A and the burner nozzles of the other recording head 3B (β = 1ch, 2ch... 50ch).

[0046] In the reference example, since the ejection deflection due to the self-airflow is not considered, the coordinate difference between the burner nozzles of one recording head 3A and the burner nozzles of the other recording head 3B shown in FIG. 12 directly becomes the coordinate difference (landing position deviation) between adjacent landing droplets. That is, |Xc(B, βch) - Xc(A, βch)| = |Xn(B, βch) - Xn(A, βch)|.

[0047] Therefore, in the reference example, as shown in FIG. 12, the Vernier nozzle with nozzle number 10ch where |Xn(B,βch) - Xn(A,βch)| is the minimum is set at the nozzle switching position. That is, in one recording head 3A, the Vernier nozzles with nozzle numbers 11 to 50ch are not driven, and in the other recording head 3B, the Vernier nozzles with nozzle numbers 1 to 10ch are not driven.

[0048] However, in reality, as shown in FIG. 13, the ink droplets ejected from the Vernier nozzles of each recording head 3A and 3B are bent in the X direction by the self-airflow.

[0049] FIG. 14 is a graph showing the landing pitch when nozzle number 10ch is set at the nozzle switching position in the case where there is a discharge bending amount θ shown in FIG. 13. As shown in FIG. 14, the difference (landing pitch) between the landing positions of the ink droplets ejected from the Vernier nozzle with nozzle number 10ch and the landing positions of the ink droplets ejected from the Vernier nozzle with nozzle number 11ch is nearly 120 [μm]. Thus, the landing pitch at the nozzle switching position is greatly deviated from the landing pitch (about 42.33 [μm]) at other positions. As a result, when setting the nozzle switching position by the method of the reference example, a large landing pitch deviation occurs at the nozzle switching position, resulting in print streaks.

[0050] Next, the setting of the nozzle switching position in this embodiment will be described. In this embodiment, for each recording head in advance, the discharge bending amount θ is investigated (see FIG. 9), and the investigated discharge bending amount θ of each nozzle number is stored in the storage unit 620 of the control unit 600 (see FIG. 4).

[0051] The control unit 600 calculates the landing coordinates of the ink droplets ejected from each Vernier nozzle of each recording head 3A and 3B based on the discharge bending amount θ of each nozzle number stored in this storage unit 620. The control unit 600 calculates the landing coordinates of the ink droplets ejected from the Vernier nozzle using the following formula 1. Xc(α,βch) =Xn(α,βch)+d×tanθ(α,βch)···(Equation 1) α: Label for identifying two adjacent recording heads 3A and 3B (One recording head 3A: A, the other recording head 3B: B) d: Distance from the nozzle surface to the recording material

[0052] The coordinates (Xn(α,βch)) of each thermal nozzle can be obtained as follows. First, after manufacturing the recording unit by combining the recording head 3A and the recording head 3B, measure the displacement amount in the X direction of the thermal nozzle (A, 1ch) at one end in the width direction of one recording head 3A with respect to the thermal nozzle (B, 1ch) at one end in the width direction of the other recording head.

[0053] The coordinates of the thermal nozzle with nozzle number 1ch of the other recording head 3B are obtained by adding a predetermined value to the reference position in the X direction. For thermal nozzles after 2ch, they can be obtained by adding the nozzle pitch P2 (P1(42.33) - Δ(0.55) = 41.78) to the coordinates of the previous thermal nozzle.

[0054] The coordinates of the thermal nozzle with nozzle number 1ch of one recording head 3A are obtained by adding a predetermined value to the reference position in the X direction and then adding or subtracting the measured displacement amount in the X direction. If the measured displacement amount in the X direction is +, add it; if the measured displacement amount in the X direction is -, subtract it. For thermal nozzles after 2ch, they can be obtained by adding the nozzle pitch P3 (P1(42.33) + Δ(0.55) = 42.88 [μm]) to the coordinates of the previous thermal nozzle.

[0055] The coordinates (Xn(α,βch)) of the Vernier nozzles of each recording head 3A, 3B are obtained in advance at the manufacturing stage, and the obtained coordinates of the Vernier nozzles are stored in the storage unit 620. Note that the coordinates (Xn(α,βch)) of the Vernier nozzles of each recording head 3A, 3B may be calculated when setting the nozzle switching position. In this case, the amount of deviation in the X direction of the first Vernier nozzle (A, 1ch) of one of the measured recording heads 3A with respect to the first Vernier nozzle (B, 1ch) of the other recording head is stored in the storage unit 620.

[0056] Based on the landing coordinates (Xc(A,βch), Xc(B,βch)) of each Vernier nozzle of each recording head 3A, 3B calculated using Equation 1, the control unit 600 calculates the landing position deviation (|Xc(B,βch) - Xc(A,βch)|) for each Vernier nozzle. Then, the control unit 600 identifies the nozzle number β of the minimum landing position deviation among the calculated multiple landing position deviations, and sets the nozzle number β as the nozzle switching position.

[0057] FIG. 15 is a graph showing the landing position deviation at each Vernier nozzle obtained based on the landing coordinates calculated from the ejection bending amount θ shown in FIG. 13. As shown in FIG. 15, the landing position deviation of the Vernier nozzle with the nozzle number 31ch is the minimum. Therefore, in this case, the Vernier nozzle with the nozzle number 31ch is set as the nozzle switching position.

[0058] FIG. 16 is a graph comparing the landing pitches between the present embodiment and the reference example. As shown in FIG. 16, in the present embodiment, the landing pitch (the difference between the landing positions of the nozzle number 31ch and the nozzle number 32ch) at the nozzle switching position (nozzle number 31ch) does not significantly differ from the landing pitches at other positions. Thus, the present embodiment can significantly improve the landing pitch deviation at the nozzle switching position as compared with the reference example.

[0059] Also, in the present embodiment, since the landing position (coordinates) of each burner nozzle is obtained by calculation to set the nozzle switching position, the nozzle switching position can be set without performing dot recording on the recording material. As a result, the nozzle switching position can be set without consuming the recording material and ink. Further, since the control unit 600 automatically sets the nozzle switching position, it is not necessary for the operator to visually set the nozzle switching position, and the work load of the operator can be reduced. In addition, compared with the case where the nozzle switching position is set visually, the nozzle switching position can be set such that the deviation of the landing pitch is more suppressed.

[0060] Furthermore, in the present embodiment, by taking into account the discharge bending amount due to the self-airflow to obtain the landing position of each burner nozzle, the landing position of each burner nozzle can be accurately obtained, and the deviation of the landing pitch at the nozzle switching position can be significantly improved.

[0061] Also, in the present embodiment, the nozzle pitch of the burner nozzles of one recording head 3A is configured to be different from the nozzle pitch of the burner nozzles of the other recording head 3B. With such a configuration, even if the recording head 3A and the recording head 3B are not positioned with high precision, in the overlap region, the displacement amount in the X direction between the burner nozzles of the same nozzle number can be made different for each nozzle number. As a result, the amount of displacement of the landing position is likely to be different for each nozzle number. Therefore, among the displacements of the landing positions of each nozzle number, the displacement amount of the minimum landing position displacement can be favorably reduced. Thus, the pitch deviation at the nozzle switching position can be favorably suppressed, and the occurrence of printing streaks can be favorably suppressed.

[0062] FIG. 17 is a control flowchart for setting the nozzle switching position. When the type of the recording material is changed or when the variation in discharge bending increases over time, etc., the user operates the operation display unit 720 to change the distance d between the nozzle surface and the recording material. For example, when the recording material is changed from paper to cloth, the distance d is increased. Also, when the variation in discharge bending increases over time, the distance d is decreased to make the printing streaks caused by the discharge bending less noticeable. When the user operates the operation display unit 720 to change the distance d between the nozzle surface and the recording material, the landing position (Xc(α,βch)) changes as can be seen from Equation 1. Therefore, when the distance d between the nozzle surface and the recording material is changed (YES in S1), the control unit 600 starts setting the nozzle switching position.

[0063] First, the control unit 600 reads out the ejection deflection amount (θ(A,βch)) and the coordinates of the burner nozzles (Xn(A,βch)) of each burner nozzle of one recording head 3A stored in the storage unit 620. Then, using the ejection deflection amount and the coordinates of each burner nozzle of the read one recording head 3A, the changed distance d between the nozzle surface and the recording material, and Equation 1 above, the landing position (Xc(A,βch)) of each burner nozzle of one recording head 3A is calculated (S12).

[0064] Next, the control unit 600 reads out the ejection deflection amount (θ(B,βch)) and the coordinates of the burner nozzles (Xn(B,βch)) of each burner nozzle of the other recording head 3B stored in the storage unit 620. Then, using the ejection deflection amount and the coordinates of each burner nozzle of the read other recording head, the changed distance d between the nozzle surface and the recording material, and Equation 1 above, the landing position (Xc(B,βch)) of each burner nozzle of the other recording head 3B is calculated (S13).

[0065] Next, the control unit 600 calculates the landing position deviation (|Xc(B,βch) - Xc(A,βch)|) for each burner nozzle (S14). Then, among the obtained multiple landing position deviations, the nozzle number β with the minimum landing position deviation is specified, and this specified nozzle number β is stored in the storage unit 620 as the nozzle switching position. The control unit 600 performs such nozzle switching position setting control for all overlap regions in each color recording unit 2K, 2C, 2M, 2Y.

[0066] Thus, in this embodiment, when the distance d between the nozzle surface and the recording material is changed, the nozzle switching position setting control is automatically performed, so that the optimal nozzle switching position can always be set.

[0067] The value of the ejection bending amount θ of the ink droplets ejected from the nozzles near the widthwise end of the recording head is large. Also, as shown in FIG. 11, the bending directions of the ink droplets of one recording head 3A and the bending directions of the ink droplets of the other recording head 3B are different from each other. Therefore, when the nozzle pitch of the burner nozzles of each recording head is constant, the landing position deviation of the burner nozzles near the end of the recording head becomes large, and the burner nozzles with the minimum landing position deviation inevitably move inward (toward the center). Therefore, in order to sufficiently suppress the deviation of the landing pitch at the nozzle switching position, it is necessary to increase the overlap area and the number of burner nozzles. As a result, the number of recording heads constituting the recording unit may increase, leading to an increase in the cost of the apparatus due to an increase in the number of parts.

[0068] However, in the case of an inkjet recording apparatus in which the ejection bending amount profiles of the burner nozzles do not differ much between the recording heads and the distance d between the nozzle surface and the recording material is not changed, the nozzle switching position can be set near the end of the recording head as the following configuration. That is, the nozzle coordinates (positions) of each burner nozzle are set in consideration of the ejection bending amount θ so that the landing pitch becomes substantially constant. Specifically, the burner nozzles are arranged so that the landing pitch of the ink droplets ejected from the burner nozzles of one recording head 3A is, for example, 42.33 + 0.55 = 42.88 [μm]. The burner nozzles are arranged so that the landing pitch of the ink droplets ejected from the burner nozzles of the other recording head 3B is 42.33 - 0.55 = 41.78 [μm]. Hereinafter, the setting of the coordinates (positions) of the burner nozzles in consideration of the ejection bending amount θ will be described as a modification example.

[0069] [Modification Example] First, in order to obtain the nozzle positions (coordinates) of each burner nozzle, the ejection bending amount θ at each position in the width direction (X direction)fit Find it. FIG. 18 is a diagram for explaining the amount of ejection bend θ at each position in the width direction (X direction). fit It is a figure explaining about the obtained side of θ. First, as shown in FIG. 18(a), for each recording head 3A, 3B, by recording dots on the recording material or the like, the amount of ejection bend θ of each nozzle is investigated, and a profile showing the relationship between each nozzle number shown in FIG. 18(a) and the amount of ejection bend θ is obtained. Next, as shown in FIG. 18(b), based on the profile of FIG. 18(a), the horizontal axis is converted from the nozzle number to the nozzle coordinates (Xn(α,βch)) of each nozzle, and a profile showing the relationship between the nozzle coordinates and the amount of ejection bend θ is obtained. Regarding the profile (dataset) showing the relationship between the nozzle coordinates and the amount of ejection bend θ shown in FIG. 18(b), the space between the nozzle coordinates is approximated by a fitting function (N-th order function), and as shown in FIG. 18(c), the amount of ejection bend θ fit (α, x) is obtained.

[0070] Next, for each recording head 3A, 3B, the target landing coordinates (Xd(α,βch)) of each burner nozzle are obtained. First, the target landing coordinates (Xd(α,1ch)) of the ink droplets ejected from the burner nozzle of nozzle number 1ch in the recording head can be obtained by using one end in the width direction of the recording material as a reference (see FIG. 19) and adding a predetermined value to this reference.

[0071] For the target landing coordinates after 2ch, they can be obtained by adding a predetermined landing pitch to the previous target landing coordinate. For one recording head, (P1 - Δ) is added as the predetermined landing pitch, and for the other recording head 3B, (P1 + Δ) is added as the predetermined landing pitch.

[0072] FIG. 19 is a diagram for explaining the setting of the nozzle coordinates (Xn(B,βch)) of the burner nozzle of the other recording head 3B. As shown in FIG. 19, the nozzle coordinates are set so that the landing pitch when the ink droplets ejected from the burner nozzle land on the recording material with the amount of ejection bend is P1 + Δ.

[0073] Specifically, the ejection bend amount θ fit (α, x) at each position in the X direction shown in FIG. 18(c) and each target landing position (Xd(α, βch)) are used to specify the coordinates (Xn(α, βch)) of each vernier nozzle that satisfies the following formula (2). tanθ fit (Xn(α, βch)) =(xd(α, βch)-Xn(α, βch)) / d ··· (2) The above θ fit (Xn(α, βch)) is the ejection bend amount at the nozzle coordinates obtained from the ejection bend amount θ fit (α, X) at each position in the X direction.

[0074] Specifically, the coordinates Xn(α, βch) of the vernier nozzle are appropriately set. Then, the ejection bend amount θ fit (Xn(α, βch)) at the set coordinates of the vernier nozzle is obtained from the ejection bend amount θ fit (α, X) at each position in the X direction. It is determined whether the formula (2) is satisfied from the appropriately set coordinates Xn(α, βch) of the vernier nozzle, the calculated ejection bend amount θ fit (Xn(α, βch)), the predetermined distance d between the nozzle surface and the recording medium, and the predetermined target landing position Xd(α, βch). If it is not satisfied, the coordinates Xn(α, βch) of the vernier nozzle are changed, and it is determined again whether the formula (2) is satisfied. If it is satisfied, the coordinates of the vernier nozzle are set to Xn(α, βch).

[0075] In this way, for all vernier nozzles, the coordinates of the vernier nozzle that satisfies the formula (2) are obtained, and each recording head 3A, 3B is manufactured so that the coordinates of each vernier nozzle become the obtained coordinates.

[0076] The landing pitch of the ink droplets ejected from the nozzle of one recording head 3A manufactured in this way is about (P1 - Δ), and the landing pitch of the ink droplets ejected from the nozzle of the other recording head 3B is about (P1 + Δ).

[0077] For example, when P1 = 42.33 [μm] (600 dpi), Δ = 0.55 [μm], d = 1.3 [mm], and Xn(B,1ch) - Xn(A,1ch) = 10 [μm], the landing position deviation (|Xc(B,βch) - Xc(A,βch)|) is the same as the result shown in FIG. 12. That is, the nozzle number with the minimum landing position deviation is 10ch. Therefore, in this modification example, the nozzle switching position can be set to the nozzle of the nozzle number 10ch, and the nozzle switching position can be set to the nozzle near the end of the recording head. As a result, the number of nozzles can be reduced, and the length of the overlap region can be reduced. Therefore, an increase in the number of recording heads constituting the recording unit can be suppressed, and an increase in the cost of the apparatus can be suppressed.

[0078] In this modification example, the landing positions of the nozzles of each recording head are already known. Therefore, when setting the nozzle switching position, it is not necessary to calculate the landing positions of the nozzles of each recording head using Equation 1. In this modification example 1, the displacement amount (Xn(B,1ch) - Xn(A,1ch)) in the X direction between the first nozzle (A,1ch) of one recording head 3A and the first nozzle (B,1ch) of the other recording head 3B is measured. Using the measured value, after correcting the target landing positions of the nozzles of the recording head 3A or 3B, the landing position deviation (|Xc(B,βch) - Xc(A,βch)|) is calculated for each nozzle. Then, among the calculated landing position deviations of each nozzle number, the nozzle of the nozzle number with the minimum landing position deviation is set as the nozzle switching position. In this modification example, since the distance d between the nozzle surface and the recording material is not changed as described above, the nozzle switching position is set at the time of factory shipment, and the set nozzle switching position is stored in the storage unit 620.

[0079] Note that in this modification example as well, as can be understood from the fact that the above formula 2 is the transposed formula of the above formula 1, the landing position Xc(α,βch) of the ink droplets ejected from each nozzle satisfies the relationship of formula 1. Therefore, also in this modification example 2, the nozzle switching position is the landing position (Xc(A,βch)) of the nozzle of one liquid ejection head that satisfies the relationship of the above formula 1 and the landing position (Xc(B,βch)) of the nozzle of the other liquid ejection head B that satisfies the relationship of the above formula 1, and the nozzle position where the difference |Xc(B,βch) - Xc(A,βch)| is minimized.

[0080] Next, another example of the apparatus for ejecting a liquid according to the present invention will be described with reference to FIGS. 20 and 21. FIG. 20 is a plan explanatory view of the main part of the apparatus, and FIG. 21 is a side explanatory view of the main part of the apparatus. This apparatus is a serial type apparatus, and the carriage 403 reciprocates in the main scanning direction by the 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, and the like. The guide member 401 is bridged between the left and right side plates 491A and 491B and holds the carriage 403 movably. Then, by the main scanning motor 405, the carriage 403 is reciprocated in the main scanning direction via the timing belt 408 bridged between the drive pulley 406 and the driven pulley 407.

[0081] This carriage 403 is equipped with a liquid discharge unit 440 that integrates the liquid discharge head device 404 and the head tank 441 according to the present invention. The liquid discharge head device 404 of the liquid discharge unit 440 is the same as the head unit 4 of the above-described embodiment, and includes, for example, a recording unit that discharges liquids of various colors such as yellow (Y), cyan (C), magenta (M), and black (K). Also, the recording units of each color in the liquid discharge head device 404 are arranged in a staggered manner with recording heads 3A and 3B each having a nozzle row composed of a plurality of nozzles, similar to the recording units 2K, 2C, 2M, and 2Y of the above-described embodiment. Further, the nozzle row direction of each color recording unit is along the sub-scanning direction (head longitudinal direction) orthogonal to the main scanning direction, and is mounted with the discharge direction facing downward.

[0082] The liquid stored outside the liquid discharge head device 404 is supplied to the head tank 441 by a supply mechanism 494 for supplying the liquid to the liquid discharge head device 404.

[0083] The supply mechanism 494 is composed of a cartridge holder 451 which is a filling part for mounting the liquid cartridge 450, a tube 456, a liquid feeding unit 452 including a liquid feeding pump, etc. The liquid cartridge 450 is detachably mounted on the cartridge holder 451. The liquid in the liquid cartridge 450 is fed to the head tank 441 by the liquid feeding unit 452 via the tube 456.

[0084] This device is provided with a conveyance mechanism 495 for conveying the paper 410. The conveyance mechanism 495 includes a conveyance belt 412 which is a conveyance means, and a sub-scanning motor 416 for driving the conveyance belt 412.

[0085] The conveyance belt 412 adsorbs the paper 410 and conveys it to a position facing the liquid discharge head device 404. This conveyance belt 412 is an endless belt and is stretched between a conveyance roller 413 and a tension roller 414. The adsorption can be performed by electrostatic adsorption or air suction.

[0086] Then, the conveyance belt 412 circulates and moves in the sub-scanning direction by the conveyance roller 413 being rotationally driven via a timing belt 417 and a timing pulley 418 by a sub-scanning motor 416.

[0087] Furthermore, on one side of the carriage 403 in the main-scanning direction, a maintenance and recovery mechanism 420 for maintaining and recovering the liquid ejection head device 404 is arranged on the side of the conveyance belt 412.

[0088] The maintenance and recovery mechanism 420 is composed of, for example, a cap member 421 that caps the nozzle surface (the surface on which nozzles are formed) of the liquid ejection head device 404, a wiper member 422 that wipes the nozzle surface, and the like.

[0089] The main-scanning movement mechanism 493, the supply mechanism 494, the maintenance and recovery mechanism 420, and the conveyance mechanism 495 are attached to a housing including side plates 491A, 491B, and a back plate 491C.

[0090] In this apparatus configured as described above, the sheet 410 is fed onto the conveyance belt 412 and adsorbed, and the sheet 410 is conveyed in the sub-scanning direction by the circulation movement of the conveyance belt 412.

[0091] Therefore, while moving the carriage 403 in the main-scanning direction, the liquid ejection head device 404 is driven according to an image signal, thereby ejecting liquid onto the stationary sheet 410 to form an image.

[0092] Thus, in this apparatus, since it is provided with the liquid ejection head according to the present invention, a high-quality image can be stably formed.

[0093] Next, another example of the liquid ejection unit according to the present invention will be described with reference to FIG. 22. FIG. 22 is a plan explanatory view of the main part of the same unit.

[0094] This liquid ejection unit is composed of a housing portion formed by side plates 491A and 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid ejection head device 404 among the members constituting the device for ejecting the liquid.

[0095] Note that a liquid ejection unit can also be configured by further attaching at least one of the above-described maintenance and recovery mechanism 420 and supply mechanism 494 to, for example, side plate 491B of this liquid ejection unit.

[0096] Next, another example of the liquid ejection unit according to the present invention will be described with reference to FIG. 23. FIG. 23 is a front explanatory view of the unit.

[0097] This liquid ejection unit is composed of a liquid ejection head device 404 to which a flow path component 444 is attached and a tube 456 connected to the flow path component 444.

[0098] Note that the flow path component 444 is disposed inside a cover 442. Instead of the flow path component 444, a head tank 441 can also be included. Further, a connector 443 for making an electrical connection with the liquid ejection head device 404 is provided above the flow path component 444.

[0099] In the present application, the "device for ejecting a liquid" is a device that includes a liquid ejection head, a liquid ejection head device, or a liquid ejection unit, and drives the liquid ejection head to eject the liquid. The device for ejecting a liquid includes not only a device capable of ejecting the liquid onto an object to which the liquid can adhere, but also a device capable of ejecting the liquid into the air or into a liquid.

[0100] This "device for ejecting a liquid" can also include means related to the feeding, conveyance, and paper discharge of an object to which the liquid can adhere, and other pretreatment devices, post-treatment devices, and the like.

[0101] For example, as a "device for discharging a liquid", there are an image forming device that discharges ink to form an image on paper, and a three-dimensional modeling device (3D modeling device) that discharges a modeling liquid onto a powder layer formed by layering powder in order to model a three-dimensional object (3D object).

[0102] In addition, the "device for discharging a liquid" is not limited to those in which a significant image such as characters or figures is visualized by the discharged liquid. For example, those that form a pattern or the like that has no meaning by itself, and those that model a three-dimensional image are also included.

[0103] The "thing to which the liquid can adhere" means something to which the liquid can adhere at least temporarily, such as something that adheres and adheres firmly, or something that adheres and penetrates. Specific examples include recording materials such as paper, recording paper, recording paper, film, cloth, electronic components such as electronic substrates and piezoelectric elements, powder layers (powder layers), organ models, and media such as test cells, and all things to which the liquid adheres are included unless otherwise particularly limited.

[0104] The material of the "thing to which the liquid can adhere" may be paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and floor materials, textile for clothing, etc., as long as the liquid can adhere even temporarily.

[0105] In addition, the "liquid" includes ink, treatment liquid, DNA sample, resist, pattern material, binder, modeling liquid, or a solution and dispersion containing amino acids, proteins, calcium, etc.

[0106] In addition, as a "device for discharging a liquid", there is a device in which a liquid discharge head and a thing to which the liquid can adhere move relative to each other, but it is not limited to this. Specific examples include a serial type device that moves the liquid discharge head, and a line type device that does not move the liquid discharge head.

[0107] In addition, the "liquid ejection device" includes a processing liquid application device that ejects a processing liquid onto a sheet in order to apply the processing liquid to the surface of the sheet for purposes such as modifying the surface of the sheet, an injection granulation device that injects a composition liquid in which raw materials are dispersed in a solution from a nozzle to granulate fine particles of the raw materials, and the like.

[0108] The "liquid ejection unit" is an integrated unit of functional components and mechanisms with a liquid ejection head, and is an aggregate of components related to liquid ejection. For example, the "liquid ejection unit" includes at least one of a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, and a main scanning movement mechanism combined with a liquid ejection head.

[0109] Here, the integration includes, for example, those in which the liquid ejection head and functional components and mechanisms are fixed to each other by fastening, adhesion, engagement, etc., and those in which one is movably held with respect to the other. Also, the liquid ejection head and functional components and mechanisms may be configured to be detachable from each other.

[0110] For example, as a liquid ejection unit, there is one in which a liquid ejection head and a head tank are integrated, such as the liquid ejection unit 440 shown in FIG. 21. Also, there is one in which a liquid ejection head and a head tank are integrated by being connected to each other with a tube or the like. Here, a unit including a filter can also be added between the head tank and the liquid ejection head of these liquid ejection units.

[0111] In addition, as a liquid ejection unit, there is one in which a liquid ejection head and a carriage are integrated.

[0112] In addition, as a liquid ejection unit, there is one in which a liquid ejection head is movably held by a guide member that constitutes a part of a scanning movement mechanism, and the liquid ejection head and the scanning movement mechanism are integrated. Also, as shown in FIG. 16, as a liquid ejection unit, there is one in which a liquid ejection head, a carriage, and a main scanning movement mechanism are integrated.

[0113] In addition, as a liquid discharge unit, there is a case where a cap member that is a part of the maintenance and recovery mechanism is fixed to a carriage to which a liquid discharge head is attached, and the liquid discharge head, the carriage, and the maintenance and recovery mechanism are integrated.

[0114] In addition, as a liquid discharge unit, as shown in FIG. 23, there is a case where a tube is connected to a liquid discharge head to which a head tank or a flow path component is attached, and the liquid discharge head and the supply mechanism are integrated.

[0115] The main scanning movement mechanism shall also include a single guide member. In addition, the supply mechanism shall include a single tube and a single loading unit.

[0116] In addition, the "liquid discharge head" is not limited to the actuator used. For example, in addition to the piezoelectric element (a laminated piezoelectric element may be used) as described in the above embodiment, a thermal actuator using an electrothermal conversion element such as a heating resistor, an electrostatic actuator including a diaphragm and a counter electrode, etc. may be used.

[0117] In addition, in the terms of the present application, image formation, recording, printing, imprinting, printing, shaping, etc. are all synonymous.

[0118] Finally, the above-described embodiments are presented as an example and are not intended to limit the scope of the present invention. Each of these novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. Such embodiments and modifications of the embodiments are included in the scope and gist of the invention and are included in the invention described in the claims and its equivalent scope.

[0119] What has been described above is an example, and each of the following aspects has specific effects. (Aspect 1) A liquid ejection head device such as a recording unit 2 that sets a nozzle switching position for switching effective nozzles that perform a liquid ejection operation within an overlapping region where two liquid ejection heads, such as two recording heads each having a plurality of nozzles arranged therein, are displaced and arranged in a direction orthogonal to the head longitudinal direction so that the head longitudinal direction range of the nozzle array in one liquid ejection head partially overlaps with the head longitudinal direction range of the nozzle array in the other liquid ejection head. The nozzle switching position is set at a nozzle position where the difference |Xc(B,βch) - Xc(A,βch)| between the landing position (XC(A,βch)) of each nozzle in the overlapping region of one liquid ejection head A that satisfies the relationship of Equation 1 and the landing position (XC(B,βch)) of each nozzle in the overlapping region of the other liquid ejection head B that satisfies the relationship of Equation 1 is minimized. Aspect 1 is such that, as shown in Equation 1, the nozzle position where the difference between the landing position Xc(A,βch) of one liquid ejection head A calculated taking into account the ejection bending amount (θ(α,βch)) of the liquid ejected from the nozzle due to self-airflow or the like and the landing position Xc(B,βch) of the other liquid ejection head is minimized is set as the nozzle switching position. Therefore, compared to a case where a nozzle position where the difference between Xc(A,βch) and Xc(B,βch) is not minimized is set as the nozzle switching position, recording unevenness due to landing pitch deviation at the nozzle switching position is suppressed.

[0120] (Aspect 2) In Aspect 1, when the distance d between the nozzle and the ejection target is changed, the nozzle switching position is set. According to this, as described in the embodiment, it is possible to always set the optimal nozzle switching position.

[0121] (Aspect 3) In Aspect 1 or 2, the nozzle pitch within the overlapping region of one liquid ejection head A and the nozzle pitch within the overlapping region of the other liquid ejection head B are different from each other. According to this, as described in the embodiment, among the landing position deviations of each nozzle number, the deviation amount of the minimum landing position deviation can be favorably reduced. Therefore, pitch deviation at the nozzle switching position can be favorably suppressed, and the occurrence of printing streaks can be favorably suppressed.

[0122] (Aspect 4) In Aspect 1 or 2, the nozzle positions of the nozzles in the overlapping region of each liquid ejection head are set so as to satisfy the above formula 2. According to this, as described in the modification, the nozzle number for which |Xc(B, βch) - Xc(A, βch)| becomes minimum can be made a smaller nozzle number compared to those in which the landing pitch is not constant due to ejection bending, and the number of nozzles in the overlapping region can be reduced. Thereby, the overlapping region can be shortened.

[0123] (Aspect 5) In Aspect 4, the landing pitch on the ejection target of the liquid ejected from the nozzles in the overlapping region of one liquid ejection head A and the landing pitch on the object to be ejected of the liquid ejected from the nozzles in the overlapping region of the other liquid ejection head B are different from each other. According to this, among the landing position deviations of each nozzle number, the deviation amount of the minimum landing position deviation can be favorably reduced. Therefore, pitch deviation at the nozzle switching position can be favorably suppressed, and the occurrence of printing streaks can be favorably suppressed.

[0124] (Aspect 6) The liquid ejection unit such as the head unit 4 includes a liquid ejection head device such as the recording unit 2 according to any one of Aspects 1 to 5. According to this, the nozzle switching position can be set without consuming the ejection target and the ink. In addition, it is possible to eliminate the need for an operator to visually set the nozzle switching position, reduce the work load of the operator, and favorably suppress pitch deviation at the nozzle switching position.

[0125] (Aspect 7) A device that discharges a liquid, such as an inkjet recording device, includes a liquid discharge head device such as a recording unit 2 according to any one of Aspects 1 to 5, or a liquid discharge unit such as a head unit 4 according to Aspect 7. According to this, the nozzle switching position can be set without consuming the discharge target and ink. Further, it is possible to eliminate the need for an operator to visually set the nozzle switching position, reduce the work burden on the operator, and also suppress pitch deviation at the nozzle switching position well.

[0126] (Aspect 8) A program executed by a computer such as a CPU 610 to set the nozzle switching position of a liquid discharge head device in which a nozzle switching position is set to switch effective nozzles for performing a liquid discharge operation from the nozzles of one liquid discharge head to the nozzles of the other liquid discharge head within an overlapping region where a head longitudinal direction range of a nozzle row in one of two liquid discharge heads in which a plurality of nozzles are respectively arranged is partially overlapped with a head longitudinal direction range of the nozzle row in the other liquid discharge head, and the two liquid discharge heads are arranged shifted in a direction orthogonal to the head longitudinal direction and partially overlapped. The program causes the computer to execute a step of obtaining the landing position (Xc(A,βch)) of each nozzle of one liquid discharge head A by the above formula 1, a step of obtaining the landing position (XC(B,βch)) of each nozzle of the other liquid discharge head B by the above formula 1, a step of calculating |Xc(B,βch)-Xc(A,βch)|, and a step of setting the nozzle position at which |Xc(B,βch)-Xc(A,βch)| becomes minimum as the nozzle switching position. According to this, pitch deviation at the nozzle switching position can be suppressed well.

Explanation of Reference Numerals

[0127] 1: Inkjet recording device 2: Recording unit 3A: One recording head 3B: The other recording head 4: Head unit 5: Nozzle 404: Liquid discharge head device 440: Liquid ejection unit 600: Control unit 610: CPU 620: Memory unit P0: Recording material P1: Normal pitch S: Ink droplet

Prior art documents

Patent documents

[0128]

Patent Document 1

Claims

1. 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 that sets a nozzle switching position for switching effective nozzles that perform a liquid ejection operation within the overlapping region from the nozzles of one liquid ejection head to the nozzles of the other liquid ejection head, The nozzle switching position is a nozzle position where the difference |Xc(B, βch)-Xc(A, βch)| between the landing position (XcA, βch) of each nozzle in the overlapping region of one liquid ejection head A, which satisfies the relationship of the following formula 1, and the landing position (Xc(B, βch)) of each nozzle in the overlapping region of the other liquid ejection head B, which satisfies the relationship of the following formula 1, is minimum: A liquid ejection head device, characterized in that the nozzle switching position is set when a distance d between the nozzle and the ejection target is changed. Xc(α, βch) =Xn(α,βch)+d×tanθ(α,βch)...(Formula 1) α: A label (A or B) for distinguishing between one liquid ejection head A and the other liquid ejection head B β: Nozzle number from one end of the head in the longitudinal direction (1, 2, ..., N (N = number of nozzles in the overlapping area)) θ(α, βch): Amount of ejection deflection of each nozzle in the overlapping area Xn(α, βch): Position of each nozzle in the overlapping region in the head longitudinal direction d: Distance between nozzle and discharge target

2. In the liquid ejection head device according to claim 1, A liquid ejection head device, characterized in that a nozzle pitch in the overlapping region of said one liquid ejection head A and a nozzle pitch in the overlapping region of said other liquid ejection head B are different from each other.

3. 2. The liquid ejection head device according to claim 1, A liquid ejection head device, characterized in that the nozzle positions of the nozzles in the overlapping regions of the liquid ejection heads are set so as to satisfy the following formula 2. tanth ｆｉｔ (Xn (a, bch)) =(Xd(α,βch)−Xn(α,βch)) / d...(Formula 2) α: A label (A or B) for distinguishing between one liquid ejection head A and the other liquid ejection head B β: Nozzle number (1, 2, ..., N (N = number of nozzles in the overlapping area)) θ ｆｉｔ (Xn(α, βch)): Amount of ejection deflection at set nozzle position Xn(α, βch): set nozzle position Xd(α, βch): Target landing position set so that the landing pitch is constant d: Distance between nozzle and discharge target

4. 4. The liquid ejection head device according to claim 3, A liquid ejection head device characterized in that the landing pitch on the ejection target of liquid ejected from nozzles in the overlapping area of ​​one liquid ejection head A is different from the landing pitch on the ejection target of liquid ejected from nozzles in the overlapping area of ​​the other liquid ejection head B.

5. A liquid ejection unit comprising the liquid ejection head device according to claim 1 .

6. 7. A liquid ejection device comprising: a liquid ejection head device according to claim 1; or a liquid ejection unit according to claim 5.

7. 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, determining the landing position (Xc(A, βch)) of each nozzle of the one liquid ejection head A by the following (Equation 3); determining the landing position (Xc(B, βch)) of each nozzle of the other liquid ejection head B by the following (Equation 3); Calculating |Xc(B, βch)-Xc(A, βch)|; and setting the nozzle position at which |Xc(B, βch)-Xc(A, βch)| is minimum as the nozzle switching position. Xc(α, βch) =Xn(α,βch)+d×tanθ(α,βch)...(Formula 3) α: A label (A or B) for distinguishing between one liquid ejection head A and the other liquid ejection head B β: Nozzle number (1, 2, ..., N (N = number of nozzles in the overlapping area)) θ(α, βch): Amount of bending of the liquid ejected from the nozzle Xn(α, βch): Nozzle position of each nozzle in the overlapping region d: Distance between nozzle and discharge target

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