Liquid dispensing device and liquid dispensing method

Abstract

To suppress deterioration in dot recording quality in a liquid discharge device which records liquid dots on a medium by an interlace recording system.SOLUTION: A liquid discharge device, which records liquid dots on a medium by an interlace recording system, has: a head which discharges a liquid from a plurality of nozzles 321; a movement mechanism which relatively moves the head and the medium in a main scanning direction and a sub scanning direction respectively; an inclination variable mechanism which changes inclination of the head with respect to the medium; and a control part which controls recording onto the medium by the liquid discharge device. According to the control part, in the state that the head is inclined at least at a first angle and a second angle by the inclination variable mechanism, a space between adjacent nozzles along the sub scanning direction is a first space in the state that the head is inclined at the first angle, and the space is a second space different from the first space in the state that the head is inclined at the second angle.SELECTED DRAWING: Figure 7

Description

Technical Field

[0006] , , , , , , ,

[0005]

[0001] The present invention relates to a liquid ejection device and a liquid ejection method.

Background Art

[0007] According to the present invention, in a liquid dispensing device that records liquid dots on a medium using an interlaced recording method, it is possible to suppress a decrease in dot recording quality. [Brief explanation of the drawing]

[0008] [Figure 1] This is a side view illustrating the overall configuration of a liquid dispensing device according to an embodiment. [Figure 2] This is a front view illustrating the overall configuration of a liquid dispensing device according to an embodiment. [Figure 3] This figure illustrates the configuration of the area surrounding the control unit according to the embodiment. [Figure 4] This diagram illustrates the configuration of a supply unit according to the embodiment. [Figure 5] This is a perspective view illustrating the configuration of the head according to the embodiment. [Figure 6] Figure 5 shows a cross-sectional view of the head cut along plane S1. [Figure 7]It is a plan view showing the configuration of the head unit according to the embodiment. [Figure 8] It is a figure explaining an example of the relationship between the inclination of the head and the nozzle pitch. [Figure 9] It is a figure explaining an example of the inclination of the head. [Figure 10] It is a figure showing an example of the connection between the head unit and the head rotation motor. [Figure 11] It is a figure showing the interlace recording method according to the comparative example. [Figure 12] It is the first figure of the first example of the interlace recording method according to the embodiment. [Figure 13] It is the second figure of the first example of the interlace recording method according to the embodiment. [Figure 14] 1]It is the first figure of the second example of the interlace recording method according to the embodiment. [Figure 15] It is the second figure of the second example of the interlace recording method according to the embodiment. [Figure 16] It is the first figure of the dot pattern in the second example of the embodiment. [Figure 17] It is the second figure of the dot pattern in the second example of the embodiment. [Figure 18] It is a flowchart showing an example of the recording operation of the liquid ejection device according to the embodiment. [Figure 19] It is a front view of an example of the movement path of the carriage according to the embodiment. [Figure 20] It is a side view of an example of the movement path of the carriage according to the embodiment. [Figure 21] It is a figure of an example of the application of the liquid ejection device according to the embodiment to an unmanned aircraft. [Figure 22] It is a figure of the first application example of the liquid ejection device according to the embodiment to an unmanned vehicle. [Figure 23] It is a figure of an example of the application of the liquid ejection device according to the embodiment to a painting robot. [Figure 24] It is a figure of the second application example of the liquid ejection device according to the embodiment to an unmanned vehicle.

Mode for Carrying Out the Invention

[0009] The liquid ejection apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. However, the following embodiments exemplify a liquid ejection apparatus for embodying the technical idea of the present embodiment, and are not limited thereto. In addition, dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments are not intended to limit the scope of the present invention only thereto, but are merely illustrative examples unless otherwise specified. Note that the sizes and positional relationships of the members shown in the respective drawings may be exaggerated for clarity of explanation. In the following description, the same names and reference numerals denote the same or similar members, and detailed descriptions thereof are omitted as appropriate.

[0010] In the following figures, the directions may be indicated by the X-axis, Y-axis, and Z-axis. The X-direction along the X-axis indicates the main scanning direction in which the carriage included in the liquid ejection apparatus according to the embodiment moves, the Y-direction along the Y-axis indicates the sub-scanning direction intersecting the main scanning direction, and the Z-direction along the Z-axis indicates the direction intersecting each of the X-direction and the Y-direction.

[0011] The direction in which the arrow points in the X-direction is denoted as the +X direction, and the opposite direction of the +X direction is denoted as the -X direction. The direction in which the arrow points in the Y-direction is denoted as the +Y direction, and the opposite direction of the +Y direction is denoted as the -Y direction. Also, the direction in which the arrow points in the Z-direction is denoted as the +Z direction, and the opposite direction of the +Z direction is denoted as the -Z direction. However, these do not limit the orientation during use of the liquid ejection apparatus, and the orientation of the liquid ejection apparatus is arbitrary.

[0012] Also, in the terms of the embodiment, recording, image formation, printing, and printing are regarded as synonyms.

[0013] [Embodiment] <Overall Configuration Example of Liquid Ejection Apparatus 1000> Referring to FIGS. 1 and 2, the configuration of the liquid ejection apparatus 1000 according to the embodiment will be described. FIGS. 1 and 2 are diagrams illustrating the overall configuration of the liquid ejection apparatus 1000, FIG. 1 is a side view, and FIG. 2 is a front view.

[0014] The liquid dispensing device 1000 records ink dots, which are an example of a liquid, onto a recording object 100, which is an example of a medium, using an interlaced recording method.

[0015] As shown in Figures 1 and 2, the liquid dispensing device 1000 includes a head 300, a moving mechanism 110, a tilt variable mechanism 120, and a control unit 500. The liquid dispensing device 1000 is installed facing the object to be recorded 100, which is an example of a medium.

[0016] The print head 300 ejects ink from each of several nozzles arranged at predetermined intervals in the Y direction. The print head 300 is mounted on the carriage 1.

[0017] The moving mechanism 110 is a mechanism that moves the head and the object to be recorded 100 relative to each other in the X and Y directions, respectively. The moving mechanism 110 includes an X-axis rail 101 and a Y-axis rail 102.

[0018] The Z-axis rail 103 holds the carriage 1 so that it can move in the Z direction. The X-axis rail 101 holds the Z-axis rail 103 so that the Z-axis rail 103, which holds the carriage 1, can move in the X direction. The Y-axis rail 102 holds the X-axis rail 101 so that the X-axis rail 101 can move in the Y direction.

[0019] The Z-direction drive unit 92 moves the carriage 1 in the Z direction along the Z-axis rail 103. The X-direction drive unit 72 moves the Z-axis rail 103 in the X direction along the X-axis rail 101. The Y-direction drive unit 82 moves the X-axis rail 101 in the Y direction along the Y-axis rail 102. Note that the movement of the carriage 1 and head 300 in the Z direction does not have to be parallel to the Z direction; it may be oblique movement as long as it includes at least a component in the Z direction.

[0020] The tilt-adjustable mechanism 120 is a rotation mechanism that changes the tilt of the head 300 relative to the object to be recorded 100. However, it is not limited to a rotation mechanism; any mechanism that can change the tilt of the head 300 relative to the object to be recorded 100, such as a tilting mechanism, may be used.

[0021] The control unit 500 is a component that controls the recording of the object to be recorded 100 by the liquid dispensing device 1000. The control unit 500 is composed of a processor or electrical circuit mounted on an electrical circuit board. The control unit 500 is electrically connected by wire or wireless means to at least the drive units that drive the moving mechanism 110 and the tilt variable mechanism 120, respectively, and to the head 300. The position of the electrical circuit board on which the control unit 500 is mounted is arbitrary, and it may be positioned remotely from the head 300, etc.

[0022] The liquid ejection device 1000 ejects ink from the head 300 toward the object to be recorded 100 while moving the carriage 1 in the X, Y, and Z directions, respectively, and records on the object to be recorded 100.

[0023] More specifically, the liquid ejection device 1000 records dots on the recordable object 100 by ejecting ink from the head 300 while moving the head 300 and the recordable object 100 relatively in the X direction, which is the main scanning direction. After completing one relative movement in the X direction, the liquid ejection device 1000 moves the head 300 and the recordable object 100 relatively in the Y direction, which is the sub-scanning direction. After completing one relative movement in the Y direction, the liquid ejection device 1000 again moves the head 300 and the recordable object 100 relatively in the X direction while ejecting ink from the head 300 to record dots on the recordable object 100. The liquid ejection device 1000 records dots on the recordable object 100 by repeating these relative movements in the X and Y directions.

[0024] Here, the relative movement of the head 300 and the object being recorded 100 in the X direction per scan is called one scan. The relative movement of the head 300 and the object being recorded 100 in the Y direction per scan is called a line break, and the amount of relative movement in a line break is called the line break amount.

[0025] If the object to be recorded 100 is a planar object aligned along the X and Y directions, the liquid dispensing device 1000 does not perform relative movement between the head 300 and the object to be recorded 100 in the Z direction during the recording operation. If the object to be recorded 100 has a shape with different heights in the Z direction, the liquid dispensing device 1000 performs relative movement between the head 300 and the object to be recorded 100 in the Z direction during the recording operation, according to the shape of the object to be recorded 100.

[0026] In Figure 1, the object to be recorded 100 is a flat plate, but it may also be a surface that is nearly vertical or has a large radius of curvature, such as a car, truck, or aircraft.

[0027] <Example of configuration of control unit 500> Figure 3 is a block diagram illustrating the configuration around the control unit 500 of the liquid dispensing device 1000. The control unit 500 is connected to the carriage 1, head unit 70, X-direction drive unit 72, Y-direction drive unit 82, Z-direction drive unit 92, head rotation drive unit 121, storage unit 501, display unit 502, and operation panel 503, etc.

[0028] The carriage 1 is equipped with a head unit 70, a tilt variable mechanism 120, and a head rotation drive unit 121, and is movable in the X, Y, and Z directions relative to the recording object 100. The head unit 70 has a head 300 and is movable in the Z direction relative to the carriage 1.

[0029] The head rotation drive unit 121 drives the tilt variable mechanism 120 to tilt the head 300 based on instructions from the control unit 500. The X-direction drive unit 72 drives the carriage 1 in the X direction based on instructions from the control unit 500. The Y-direction drive unit 82 drives the carriage 1 in the Y direction based on instructions from the control unit 500. The Z-direction drive unit 92 drives the carriage 1 in the Z direction based on instructions from the control unit 500.

[0030] The control unit 500 includes a CPU that controls the entire liquid dispensing device 1000, and a ROM that stores programs and other fixed data for executing control operations such as recording operations on the CPU. The control unit 500 also includes a RAM that temporarily stores recording data such as patterns and characters drawn on the object to be recorded 100, as well as body data of the object to be recorded 100, and an I / F for sending and receiving data and signals used when receiving recording data from a host such as a PC.

[0031] The control unit 500 drives the carriage 1 and the head unit 70 by controlling the operation of the X-direction drive unit 72, the Y-direction drive unit 82, the Z-direction drive unit 92, and the head rotation drive unit 121, respectively. The control unit 500 also controls the ejection of ink from the head 300 provided on the head unit 70.

[0032] The control unit 500 will notify the user by displaying an abnormality on the display unit 502 if an abnormality occurs in the operation of the carriage 1, head unit 70, or head 300. The control unit 500 also receives instructions from the operation panel 503. The display unit 502 will notify the user by displaying the details of any abnormality that occurs in the liquid dispensing device 1000.

[0033] The control panel 503 is used to input values ​​(coordinates) for identifying the area (recording area) where ink is ejected onto the object to be recorded 100, the movement speed of the carriage 1, the identification of recording data and 3D coordinate information (body data) used for recording onto the object to be recorded 100, and the distance between the head 300 and the object to be recorded 100. The display unit 502 and the control panel 503 may be operated on a single screen using a touch panel or the like.

[0034] <Example configuration of supply unit 200> Figure 4 illustrates the configuration of the supply unit 200 in the liquid dispensing device 1000. The supply unit 200 supplies ink to the head unit 70, which includes the head 300. The head unit 70 includes a head 300Y that dispenses yellow (Y) ink, a head 300M that dispenses magenta (M) ink, a head 300C that dispenses cyan (C) ink, and a head 300K that dispenses black (K) ink.

[0035] Furthermore, the head unit 70 may have a head 300Q for ejecting overcoat ink and a head 300P for ejecting primer ink or white ink, as well as heads for ejecting other inks. Head 300 is a general term used when not specifically distinguishing between heads 300Y, 300M, 300C, 300K, 300Q, and head 300P. The supply unit 200 supplies ink of each color to each color head 300.

[0036] The supply unit 200 includes an ink tank 330, which is a sealed container holding ink 325 of each color ejected from each head 300. The ink tank 330 and the inlet (supply port) of the head 300 are connected via tubes 333 to allow ink to flow.

[0037] Meanwhile, the ink tank 330 is connected to the compressor 230 via a pipe 331 containing an air regulator 332, and the compressor 230 supplies pressurized air. As a result, the liquid ejection device 1000 supplies pressurized ink 325 of each color to the inlet of each head 300, and ejects the ink 325 from the nozzle of each head 300.

[0038] <Example configuration of head 300> Figures 5 and 6 illustrate the configuration of the head 300. Figure 5 is a perspective view, and Figure 6 is a cross-sectional view of the head 300 cut along plane S1 in Figure 5.

[0039] The head 300 has a plurality of discharge modules 310 arranged in one or more rows within the housing 10.

[0040] The print head 300 has a supply port 11 and a recovery port 12. The supply port 11 supplies externally pressurized ink to the ejection module 310, and the recovery port 12 discharges any un-ejected ink to the outside. The housing 10 also has a connector 2.

[0041] The ejection module 310 includes a nozzle plate 311 equipped with a nozzle 321 for ejecting ink, a flow path 322 through which the nozzle 321 communicates and supplies pressurized liquid, and a piezoelectric element 324 that drives a needle-shaped valve body for opening and closing the nozzle 321.

[0042] The nozzle plate 311 is joined to the housing 10. The flow path 322 is a common flow path for multiple ejection modules 310 provided in the housing 10, supplying pressurized ink from the supply port 11 and discharging ink from the recovery port 12. During the period when ink is being ejected to the object to be recorded 100, the discharge of ink from the recovery port 12 may be temporarily suspended in order to avoid reducing the ink ejection efficiency from the nozzle 321.

[0043] Figure 7 is a plan view of the head unit 70 as seen from the side of the object to be recorded 100. Each head 300 included in the head unit 70 has a plurality of nozzles 321 arranged with a nozzle pitch R between them, and ink is ejected from each of the plurality of nozzles 321. Nozzle pitch refers to the distance between adjacent nozzles 321. Adjacent nozzles 321 refer to the two nozzles 321 that are closest to each other among the plurality of nozzles 321.

[0044] Head 300Q ejects overcoat ink, head 320K ejects black ink, head 300C ejects cyan ink, head 300M ejects magenta ink, head 300Y ejects yellow ink, and head 300P ejects primer or white ink. The order in which the heads 300 are arranged is just an example, and there are no particular restrictions on the order. Also, all heads in the head unit 70 may eject ink of the same color.

[0045] In this embodiment, the head 300 can be tilted relative to the object to be recorded 100. The liquid ejection device 1000 allows the spacing of dots recorded on the object to be recorded 100 in the X and Y directions to be varied by the angle at which the head 300 is tilted by the tilt variable mechanism 120.

[0046] Figure 8 illustrates an example of the relationship between the tilt of the head 300 and the nozzle pitch. In Figure 8, the head 300 is tilted at an angle θ with respect to the X direction (main scanning direction), so the arrangement direction of the nozzles 321 on the head 300 is tilted at an angle θ with respect to the X direction. The nozzle pitch R is the nozzle pitch along the arrangement direction. If the pitch of adjacent nozzles along the X direction is Rx and the pitch of adjacent nozzles along the Y direction (sub-scanning direction) is Ry, then the nozzle pitches Rx and Ry are expressed as follows. Rx = R × cosθ Ry = R × sinθ

[0047] Here, the nozzle pitch Ry of adjacent nozzles along the Y direction refers to the distance between the closest nozzles 321 along the Y direction. Even if one of the two nozzles 321 is offset along the X direction relative to the other nozzle 321, if the distance between them along the Y direction is the shortest, then these two nozzles 321 are adjacent nozzles along the Y direction. The distance between these two nozzles along the Y direction corresponds to the nozzle pitch Ry.

[0048] Figure 9 illustrates an example of the tilt of the head 300, showing the head 300 tilted by the tilt variable mechanism 120.

[0049] Figure 9 shows eight nozzles 321 numbered N2 to N8, with the nozzle 321 furthest to the -X direction being the reference nozzle N1, and moving toward the +X direction. The tilt variable mechanism 120 can change the tilt of the head 300 by rotating the head 300 around the Z axis, with the reference nozzle N1 as the rotation center.

[0050] For example, the variable tilt mechanism 120 can shorten the nozzle pitch Ry along the Y direction by rotating the head 300 clockwise, and lengthen the nozzle pitch Ry along the Y direction by rotating the head 300 counterclockwise.

[0051] When the angle θ is negative with respect to the X-axis (the angle obtained by rotating clockwise around the reference nozzle N1), the positional relationship of the nozzle 321 is reversed, and the nozzle pitch Ry at angle -θ becomes the same as the nozzle pitch Ry at angle θ. The reference nozzle N1 will be located furthest towards the +Y direction. Table 1 shows the relationship between the angle θ of the head 300 and the nozzle pitch Ry in the Y direction. [Table 1]

[0052] If the number of nozzles 321 in the head 300 is N, then in order to record without dot gaps (a state in which dots are not recorded in the positions where dots should be recorded) or dot overlaps (a state in which at least some of multiple dots overlap on the recordable object 100), the amount of line breaks in the Y direction is proportional to the number of dots N and is expressed in Table 2 below according to the number of interlaces. The number of interlaces must be an odd number. Here, the number of interlaces refers to the number of times the head and the recordable object are moved relative to each other in order to record dots in a predetermined area on the recordable object using the interlaced recording method. [Table 2]

[0053] Here, we have described how the nozzle pitch Ry in the Y direction is changed by changing the tilt of the head 300, but the nozzle pitch Rx in the X direction also changes. For this reason, when recording dots on the object to be recorded 100, it is preferable for the liquid ejection device 1000 to correct the position where the ink is recorded by changing the ink ejection timing in the X direction. The liquid ejection device 1000 shall perform this correction as appropriate.

[0054] <Example of connection between head unit 70 and head rotation drive unit 121> Figure 10 shows an example of the connection between the head unit 70 and the head rotation drive unit 121.

[0055] As shown in Figure 10, a shaft 121a extending from the head rotation drive unit 121 is connected to the head 300, and the rotational drive of the head rotation drive unit 121 changes the inclination of the head 300 with respect to the recording surface of the object to be recorded 100. The liquid discharge device 1000 may change the rotation ratio between the head rotation drive unit 121 and the head 300 by using a transmission mechanism such as gears.

[0056] By setting the rotation center of the head 300 by the head rotation drive unit 121 to, for example, the reference nozzle N1 in Figure 9, the movement of the head 300 in the Y direction can be suppressed.

[0057] <Interlaced recording method and its effects> Next, we will explain the interlaced recording method and how it works.

[0058] Here, the interlaced recording method refers to a method in which dots are recorded on the object to be recorded 100 at intervals narrower than the distance between adjacent nozzles on the head, by recording dots in a predetermined area on the object to be recorded 100 through multiple relative movements between the head 300 and the object to be recorded 100.

[0059] In the interlaced recording method, the liquid ejection device 1000 ejects ink from the nozzle 321 of the head 300 when the head 300 is moving in the X direction, for example. The liquid ejection device 1000 performs two-dimensional dot recording on the object to be recorded 100 by combining the movement of the head 300 along the X direction and the movement of the head 300 along the Y direction.

[0060] When the liquid ejector 100 completes a pattern with a desired recording resolution in a predetermined area on the object to be recorded 100 through T scans, it intermittently moves the head 300 in the Y direction for the 1st, 2nd, 3rd, ... scans. The head 300 and the object to be recorded 100 are in a positional relationship such that they connect at a position on the head 300 corresponding to the length of the nozzle row in which the nozzles 321 are arranged, on the (T+1) scan. In order for the T recording operations to be seamlessly connected, the liquid ejector 1000 moves the head 300 in the Y direction by "nozzle row length + 1 nozzle pitch" from the position of the head 300 in the Y direction of the 1st scan and performs the (T+1) scan.

[0061] As an example, consider a case where the number of nozzles per inch in the head 300 is 100, and the liquid dispensing device 1000 performs dot recording a total of 8 times, 2 times in the X direction and 4 times in the Y direction, with a recording resolution of 600 dpi in the X direction and 400 dpi in the Y direction.

[0062] In the case of a recording resolution of 600 dpi in the X direction and 400 dpi in the Y direction, the spacing between adjacent dots along the X direction on the object to be recorded 100 is 25.4 (mm) / 600 ≈ 42.3 (μm), and the spacing between adjacent dots along the Y direction is 25.4 (mm) / 400 = 63.5 (μm). The movement amount and position of the head 300 are controlled based on this recording resolution in the movement control and ink ejection timing control from the head 300. For example, when M=8, eight dots are recorded in a predetermined area on the object to be recorded 100 through eight scans.

[0063] The interlaced recording methods and their operations for the comparative example, the first embodiment, and the second embodiment will be described below with reference to Figures 11 to 15.

[0064] (Comparative example) Figure 11 illustrates an interlaced recording method for a comparative example. In Figure 11, the position of the head 300X indicates its position in the Y direction when it moves relative to the X direction. The dot pitch Dy represents the minimum pitch in the Y direction of the dots recorded on the recording object 100, and corresponds to the recording resolution. For example, when the number of interlaces is 3, the following relationship holds. Dy = Ry / 3

[0065] "Scan" means scanning, and a line break is performed with a line break amount F after each scan. In Figure 11, each square in the dot pattern area A represents a dot recorded on the object to be recorded, and the numbers 1 to 8 displayed in each square correspond to the nozzle numbers of the eight nozzles in the head 300X that ejected the dot recorded at the position of each square.

[0066] In the example shown in Figure 11, the number of nozzles N in the head 300X is 8, and the dot pattern area A is repeatedly recorded along the Y direction in a period corresponding to 8 dots along the Y direction. The 8 dots arranged in the Y direction are recorded by ink ejected from each of the 8 nozzles. This period does not depend on the number of interlaces.

[0067] (Example of Embodiment 1) Next, Figures 12 and 13 illustrate a first example of the interlaced recording method according to this embodiment. Figure 12 is Figure 1, and Figure 13 is Figure 2. Figures 12 and 13 show the position of the head 300 after 12 scans; Figure 12 shows the position of the head 300 in the first half, and Figure 13 shows the position of the head 300 in the second half. Note that the same terms used in the description of the comparative example have the same meaning, and redundant explanations will be omitted here as appropriate. This also applies to the second example which will be described after the first example.

[0068] In the first example, the line break amount F is approximately the same across multiple scans. Note that "approximately the same" does not require a strict match, but rather allows for a difference that is generally considered within the margin of error. A difference generally considered within the margin of error is, for example, a distance of F / 10, and in this case, the effects of the embodiment are obtained similarly.

[0069] The control unit 500 of the liquid discharge device 1000 moves the head 300 and the object to be recorded 100 relative to each other in the X direction when the tilt of the head 300 is set to at least a first angle and a second angle by the tilt variable mechanism 120. The first angle θ1 and the second angle θ2 are predetermined. The first angle θ1 and the second angle θ2 can be appropriately determined according to the number of interlaces, the number N of nozzles 321 in the head 300, or the spacing between the nozzles 321.

[0070] In this embodiment, in the head 300, the distance between adjacent nozzles 321 along the Y direction is a first distance when the head 300 is tilted to a first angle, and a second distance different from the first distance when the head 300 is tilted to a second angle.

[0071] For example, if the inclination of the head 300 is defined as a first angle θ0 and a second angle θ2, then, as shown in Table 1 above, the nozzle pitch Ry0 at the first angle θ0 corresponds to the first interval, and the nozzle pitch 3 × Ry0 at the second angle θ2 corresponds to the second interval. In this embodiment in particular, the nozzle pitch 3 × Ry0, which is the second interval, is an integer multiple of 2 or more of the nozzle pitch Ry0, which is the first interval. Also, in the first example of this embodiment in particular, the nozzle pitch 3 × Ry0 is an odd multiple of 2 or more of the nozzle pitch Ry0.

[0072] As shown in Figures 12 and 13, the number of nozzles 321 in the head 300 is 8, and the dot pattern area B is repeatedly recorded along the Y direction with a period of 24 dots along the Y direction. 24 dots arranged in the Y direction are recorded by each of the 8 nozzles. The period of this dot pattern area B for 24 dots in the Y direction is determined by the product of the number of nozzles 321 (N) = 8 and the interlacing number = 3.

[0073] Here, the liquid ejection device 1000 can record a dot pattern area with higher randomness along the Y direction on the object to be recorded 100 as the period of the dot pattern area B is increased (the number of dots is increased). A dot pattern area with higher randomness means that the ink ejection nozzles that form each dot in the dot pattern area are diverse.

[0074] Multiple nozzles on a print head may contain variations in nozzle spacing or individual nozzle ink ejection characteristics. These variations include, for example, a particular nozzle ejecting less ink than other nozzles, or a particular nozzle ejecting in a different direction than other nozzles. Depending on these nozzle variations, the dots recorded on the material may be misaligned, resulting in unintended dot patterns. Dot misalignment along the Y-direction can cause banding, which is a streaky density variation extending in the X-direction.

[0075] In the Y-direction, banding is more noticeable in dot pattern regions with low randomness compared to dot pattern regions with high randomness. For example, in the interlaced recording method described in the comparative example, a dot pattern region with a period of 8 dots is recorded along the Y-direction. Therefore, the bias error of the 8 nozzles leads to a misalignment of the 8 dots along the Y-direction. The pattern of dots that are misaligned along the Y-direction extends in the X-direction, making banding more noticeable.

[0076] The liquid ejection device 1000 according to this embodiment allows the dot pattern area B to be recorded by ink ejected from a wider variety of nozzles 321 by lengthening the period along the Y direction of the dot pattern area B to the length of 24 dots. As a result, the randomness of the dot pattern area B is increased, and the bias in dot position due to nozzle bias errors is dispersed on the object to be recorded 100, making banding less noticeable.

[0077] Here, the dot recording state on the recording object 100 shown in Figures 12 and 13 is just one example, and the liquid dispensing device 1000 can make the dot recording state different depending on the combination of nozzle pitch Ry for each scan. Table 3 shows examples of nozzle pitch Ry combinations. [Table 3]

[0078] In Table 3, for example, in Method 1, the nozzle pitch Ry in the first scan is Ry0, in the second scan it is Ry0, and in the third scan it is 3×Ry0. In Method 3, the nozzle pitch Ry in the first scan is Ry0, in the second scan it is 3×Ry0, and in the third scan it is 5×Ry0. In this way, the liquid dispensing device 1000 can vary the recording state of the dots on the recording object 100 by changing the nozzle pitch Ry for each scan and changing the combination of nozzle pitches Ry. The same effect can be obtained in any of the methods shown in Table 3.

[0079] Generalizing the interlaced recording method in the first example, if the number of nozzles 321 in the head 300 is N, the nozzle pitch in the Y direction at a reference tilt angle θ0 is Ry0, and the number of interlaces is K (where K is an odd number), then the dot pitch Dy is Ry0 / K, and the line break amount is Y / K × N.

[0080] The liquid dispensing device 1000 ensures that the nozzle pitch Ry along the Y direction is the same value for each period of the dot pattern area (for example, a period corresponding to 24 dots). Furthermore, the liquid dispensing device 1000 ensures that the nozzle pitch Ry along the Y direction is not the same for all scans, but at least partially different for each scan (1st scan, 2nd scan, 3rd scan, ..., Kth scan). In addition, the liquid dispensing device 1000 ensures that the nozzle pitch Ry for each scan is an odd multiple of the reference nozzle pitch Ry0. As a result, the liquid dispensing device 1000 can record a dot pattern area on the recording object 100 with a period of N × K. This dot pattern area will differ depending on the nozzle pitch Ry at each scan.

[0081] (Second example of an embodiment) Next, Figures 14 and 15 illustrate a second example of the interlaced recording method according to this embodiment. Figure 14 is Figure 1, and Figure 15 is Figure 2. Figures 14 and 15 show the position of the head 300 after 12 scans, with Figure 14 showing the position of the head 300 in the first half and Figure 15 showing the position of the head 300 in the second half.

[0082] Similar to the first example, the control unit 500 of the liquid dispensing device 1000 moves the head 300 and the object to be recorded 100 relative to each other in the X direction when the tilt of the head 300 is set to at least a first angle and a second angle by the tilt variable mechanism 120. In addition, the distance between adjacent nozzles 321 along the Y direction on the head 300 is a first distance when the head 300 is tilted to a first angle, and a second distance different from the first distance when the head 300 is tilted to a second angle.

[0083] In the second example, the line break amount F is not the same for each line break that occurs in response to multiple scans; at least some of the line break amounts F are different. Also in the second example, the second interval is an even multiple of the first interval.

[0084] As shown in Figures 14 and 15, the number of nozzles 321 in the head 300 is 8, and the dot pattern region C is repeatedly recorded along the Y direction with a period of 96 dots along the Y direction. 96 dots arranged in the Y direction are recorded by each of the 8 nozzles.

[0085] The liquid dispensing device 1000 may shift the scan start position of the head 300 during each scan by units of nozzle pitch Rx along the X direction. By shifting the nozzle pitch Rx, a dot pattern area with higher randomness can be recorded on the object to be recorded 100.

[0086] In the examples in Figures 14 and 15, the relationship between the scan order and the nozzle pitch Ry in the Y direction is shown in Table 4 below. Note that in Table 4, the scan order means, for example, "1" is the first scan and "4" is the fourth scan. [Table 4]

[0087] The number of dots along the Y direction in the dot pattern region C, which is 96, is determined by the product of the number of nozzles 321 N, the interlacing number K, and the maximum value of the multiple at even multiples of the first interval. For example, if the number N is 8, the interlacing number K is 3, and the maximum value of the multiple at even multiples of the first interval is 4, then the number of dots, 96, is obtained by the product of 8 × 3 × 4.

[0088] The upper limit of the number of dots in the dot pattern region C can be further increased by increasing the variety of nozzle pitches Ry along the Y direction.

[0089] Furthermore, the liquid discharge device 1000 can reverse the arrangement of the nozzles 321 along the Y direction by reversing the tilt direction of the head 300 using the tilt variable mechanism 120. Combining this with the second example can further increase the randomness of the dot pattern region C. Note that in the second example, since the amount of line breaks is not constant, the tilt variable mechanism 120 does not have to be a rotation mechanism centered on the reference nozzle N1 (see Figure 9).

[0090] Figures 16 and 17 show examples of the dot pattern in the second example, with Figure 1 being Figure 1 and Figure 17 being Figure 2. Figure 16 shows the first half of the dot pattern along the Y direction, and Figure 17 shows the second half of the dot pattern along the Y direction.

[0091] The interlace number K in the dot patterns shown in Figures 16 and 17 is 3. Dots 151, shown by diagonal hatching, are dots with a nozzle pitch Ry0 and are recorded at equal intervals along the Y direction. Dots 152, shown by light dot hatching, are dots with a nozzle pitch of 2 × Ry0 and are recorded at equal intervals along the Y direction while moving back and forth by the equivalent of one dot in the X direction. Dots 153, shown by dark dot hatching, are dots with a nozzle pitch of 4 × Ry0 and are recorded at equal intervals along the Y direction while moving back and forth by the equivalent of four dots in the X direction.

[0092] However, the liquid dispensing device 1000 does not necessarily need to arrange the dot patterns shown in Figures 16 and 17 as continuous blocks. For example, the liquid dispensing device 1000 can create a more random nozzle pattern by shifting the scan start position of the head 300 during each scan so as to span each of the patterns in Figures 16 and 17.

[0093] Let N be the number of nozzles 321 in the head 300, and Ry0 be the nozzle pitch along the Y direction when the tilt angle θ0. Generalizing the first and second examples together, we get the following: (1) When the number of interlaces K is odd The dot pitch will be Ry0 / K. The nozzle pitch Ry can be any number of combinations of positive odd multiples of nozzle pitch Ry0, resulting in K possible combinations. Note that K may be the same value, but the case where all nozzle pitches Ry are exactly 1x of nozzle pitch Ry0 is not included in this embodiment. The nozzle pitch Ry can be 1x or a positive even multiple of the nozzle pitch Ry0, resulting in K possible combinations. Note that K may be the same value, but the case where all nozzle pitches Ry are 1x the nozzle pitch Ry0 is not included in this embodiment.

[0094] (2) When the number of interlaces K is even The dot pitch will be Ry0 / K. The nozzle pitch Ry can be 1x or a positive even multiple of the nozzle pitch Ry0, resulting in K possible combinations. Note that K may be the same value, but the case where all nozzle pitches Ry are 1x the nozzle pitch Ry0 is not included in this embodiment.

[0095] According to (1) or (2) above, the number of dots along the Y direction of the dot pattern region is determined by the product of the number of nozzles 321 N, the number of interlaces K, and the maximum value of the multiples at even multiples of the first interval. This dot pattern region changes with the nozzle pitch Ry during each scan.

[0096] <Example of operation of liquid dispensing device 1000> The operation of the liquid dispensing device 1000 will be described with reference to Figures 18 to 20. Figure 18 is a flowchart showing an example of the recording operation of the liquid dispensing device 1000. Figure 19 is a front view showing an example of the movement path of the carriage 1. Figure 20 is a side view showing an example of the movement path of the carriage 1. Figures 19 and 20 show the movement trajectory of the carriage 1 as 1R.

[0097] When the liquid dispensing device 1000 receives a recording start instruction from the control unit 500, it starts the operation shown in Figure 18.

[0098] First, in step S181, the liquid dispensing device 1000, controlled by the control unit 500, controls the X-direction drive unit 72, the Y-direction drive unit 82, and the Z-direction drive unit 92 to move the carriage 1 to the recording start standby position 112 in Figure 19. The recording start standby position 112 is a position located a predetermined distance away from the recording area of ​​the object to be recorded 100 in the -X direction, and is located further away in the Z direction from the recording surface of the object to be recorded 100 than during recording.

[0099] Next, in step S182, the liquid ejection device 1000 performs maintenance operations on the head 300 at the recording start standby position 112. The maintenance operations are performed to maintain and restore the ink ejection function of the head 300, and include operations such as discharging the thickened ink from inside the head 300 and wiping the nozzle plate 311 of the head 300.

[0100] Next, in step S183, the liquid ejection device 1000 controls the X-direction drive unit 72 and the Z-direction drive unit 92 by the control unit 500, so that the carriage 1 moves toward the +X direction as shown in Figure 20, and performs a recording operation based on the recording data that will be the source data for recording. That is, the liquid ejection device 1000 ejects ink from the nozzle 321 while moving the carriage 1 toward the +X direction by the control unit 500.

[0101] When the carriage 1 leaves the recording area, the liquid dispensing device 1000 controls the X-direction drive unit 72 and the Z-direction drive unit 92 via the control unit 500, moving the carriage 1 toward the +X direction while moving it toward the direction away from the recording surface (-Z direction), and stopping it at the inversion position 111.

[0102] Next, in step S184, the liquid dispensing device 1000, with the control unit 500, determines whether or not to terminate the recording.

[0103] In step S184, if it is determined that recording should not be terminated because there is recording data or for other reasons (step S184, No), in step S185, the liquid dispensing device 1000 controls the Y-direction drive unit 82 by the control unit 500 to move the carriage 1 to the -Y direction.

[0104] Next, in step S186, the liquid dispensing device 1000 determines whether or not to change the tilt of the head 300 using the control unit 500.

[0105] If it is determined in step S186 that no change is needed (step S186, No), the liquid dispensing device 1000 proceeds to step S182 and repeats the operations from step S182 onward.

[0106] On the other hand, if it is determined in step S186 to make a change (step S186, Yes), in step S187, the liquid dispensing device 1000 controls the tilt variable mechanism 120 with the control unit 500 to change the tilt of the head 300. After that, the liquid dispensing device 1000 moves to step S182 and repeats the operations from step S182 onward.

[0107] Here, the direction of movement of carriage 1 in step S183 can be either towards the -X direction or towards the +X direction, depending on the position where step S185 was executed.

[0108] Furthermore, if it is determined in step S184 to terminate recording (step S184, Yes), in step S188, the liquid ejection device 1000 performs maintenance on the head 300 at the recording start standby position 112, and then terminates its operation. This allows the liquid ejection device 1000 to terminate its operation after removing any residual ink from the nozzle plate 311.

[0109] As described above, the liquid dispensing device 1000 can record ink dots on the object to be recorded 100.

[0110] <Effects of Liquid Dispensing Device 1000> As described above, the liquid ejection device 1000 records ink (liquid) dots onto the recording object 100 (medium) using an interlaced recording method. The liquid ejection device 1000 includes a head 300 that ejects ink from each of a plurality of nozzles 321, a movement mechanism 110 that moves the head 300 and the recording object 100 relative to each other in the X direction (main scanning direction) and the Y direction (sub-scanning direction) intersecting the X direction, a tilt variable mechanism 120 that changes the tilt of the head 300 relative to the recording object 100, and a control unit 500 that controls the recording of dots onto the recording object 100 by the liquid ejection device 1000.

[0111] The control unit 500 moves the head 300 and the object to be recorded 100 relative to each other in the X direction when the tilt of the head 300 is set to at least a first angle (e.g., angle θ0) and a second angle (e.g., angle 2 × θ0) by the tilt variable mechanism 120. The distance between adjacent nozzles 321 along the Y direction is the first distance (e.g., nozzle pitch Ry0) when the head 300 is tilted to the first angle, and the distance is a second distance (e.g., nozzle pitch 2 × Ry0) which is different from the first distance when the head 300 is tilted to the second angle.

[0112] For example, in the interlaced recording method described in the comparative example, the relative positions of the nozzles in head 300X remain constant in the Y direction during repeated scanning, which makes banding more noticeable. This can result in a decrease in the quality of dot recording on the material being recorded.

[0113] In this embodiment, the tilt of the head 300 is changed in at least some of the scans among the multiple scans, so that the relative positions of the nozzles 321 are not constant for each scan. This allows the liquid ejection device 1000 to increase the randomness of the dot pattern area and makes banding less noticeable. Thus, in this embodiment, it is possible to suppress the deterioration of dot recording quality in a liquid ejection device that records liquid dots on a medium using an interlaced recording method.

[0114] In this embodiment, the second interval is an integer multiple of 2 or more of the first interval. This provides the same effects as described above.

[0115] As shown in the first example, in this embodiment, the moving mechanism 110 performs multiple operations consisting of relative movement of the head 300 and the recorded object 100 in the X direction, and relative movement of the head 300 and the recorded object 100 in the Y direction. The amount of line breaks F per line break (relative movement in the Y direction) is the same in all of the multiple line breaks, and the second interval is an odd multiple of 2 or more of the first interval. This provides the same effects as described above.

[0116] Furthermore, as shown in the second example, in the liquid dispensing device 1000, the relative movement amount per line break differs at least in some line breaks, and the second interval may be an even multiple of the first interval. In this case as well, the same effects as described above can be obtained.

[0117] Furthermore, odd multiples of the first interval may be approximately odd multiples of the first interval, and even multiples of the first interval may be approximately even multiples of the first interval. These approximately odd and even multiples do not require strictly odd and even multiples, but rather mean that a difference of a degree generally considered to be within the margin of error is permitted. A difference of a degree generally considered to be within the margin of error is a distance of 1 / 10 or less of the first interval, and in this case, the same effect as described above can be obtained.

[0118] While we have used 8 nozzles as an example for the number of nozzles N, this is not limited to this, and the number of nozzles can be changed as appropriate.

[0119] [Other Preferred Embodiments] The following describes an example of the application of the embodiment using Figures 21 to 24. The embodiment can also be applied to an unmanned aerial vehicle 6000, such as a drone, as shown in Figure 21. The unmanned aerial vehicle 6000 controls its position based on the detection results of a detector 610, such as a distance measuring sensor, mounted on itself. The unmanned aerial vehicle 6000 is equipped with an ink-dispensing head 620, and ink contained in a liquid tank 630 is supplied to the head 620 via a cable 640. Based on the above position control, the unmanned aerial vehicle 6000 discharges ink from the head 620 toward the object to be recorded 100 (the wall surface of a building in this embodiment) and applies the ink to the painted area P of the object to be recorded 100. In this case, the head 300 according to the embodiment can be used as the head 620.

[0120] Furthermore, the embodiment can also be applied to an unmanned vehicle 7000, such as the wall-climbing robot shown in Figure 22. The unmanned vehicle 7000 can move by driving the roller 710 while sucking the object to be recorded 100 (the wall surface of a building in this embodiment) from the bottom of the unmanned vehicle 7000. The unmanned vehicle 7000 is equipped with an ink-dispensing head 720, and ink contained in a liquid tank 730 is supplied to the head 720 via a cable 740. The unmanned vehicle 7000 then discharges ink from the head 720 toward the object to be recorded 100 (the wall surface of a building in this embodiment), and applies the ink to the painted area P of the object to be recorded 100. In this case, the head 300 can be used as the head 720.

[0121] Furthermore, the embodiment can also be applied to a painting robot 8000 for painting, for example, the body of an automobile, as shown in Figure 23. The painting robot 8000 is equipped with a robot arm 810 that has multiple joints to allow for free movement like a human arm, and a head 820 that ejects ink at the tip of the robot arm 810. The robot arm 810 is also equipped with a 3D sensor 830 near the head 820. As the painting robot 8000, a multi-joint robot with an appropriate number of axes, such as 5 axes, 6 axes, or 7 axes, can be used. The painting robot 8000 detects the position of the head 820 relative to the object to be recorded 100 (the car body in this embodiment) using the 3D sensor 830, and moves the robot arm 810 to paint the object to be recorded 100 based on the detection result. In this case, the head 300 according to the embodiment can be used as the head 820.

[0122] Furthermore, the embodiment can also be applied to an unmanned vehicle 9000, such as the road-walking robot shown in Figure 24. The unmanned vehicle 9000 can move along the object to be recorded 100 (in this embodiment, the road surface such as a roadway or sidewalk) by driving the wheels 910. The unmanned vehicle 9000 is equipped with an ink-dispensing head 920, and ink contained in a liquid tank 930 is supplied to the head 920 via a cable 940. The unmanned vehicle 9000 then discharges ink from the head 920 toward the object to be recorded 100, applying the ink to the painted area P of the object to be recorded 100, thereby forming, for example, a crosswalk, stop line, center line, etc., on the road surface. In this case, the head 300 according to the embodiment can be used as the head 920.

[0123] Alternatively, instead of the configuration of the embodiment, the printing medium may be driven while the head is stopped to perform sub-scanning movement. That is, the configuration may include a support member for supporting the object to be recorded 100, and a motor as a drive source for moving the support member relative to the head.

[0124] In the embodiment, the liquid ejected from the head may be a solution, suspension, emulsion, etc., containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a polymerizable compound, a resin, a functional material such as a surfactant, a biocompatible material such as DNA, amino acids or proteins, calcium, or an edible material such as a natural pigment. These can be used, for example, as inkjet inks, coatings, surface treatment liquids, liquids for forming components of electronic elements or light-emitting elements or electronic circuit resist patterns, and material liquids for 3D molding. Furthermore, the liquid ejection device according to the embodiment is not limited to the form shown in Figure 1. It may be an inkjet printer for printing images onto paper. It may also be a multifunction device equipped with functions such as scanning and faxing in addition to printing.

[0125] The term "medium" refers to anything to which a liquid adheres and solidifies, or to which a liquid adheres and penetrates. Specific examples include recording media such as car bodies, building materials, paper, recording paper, film, and cloth; electronic components such as electronic circuit boards and piezoelectric elements; powder layers; organ models; and inspection cells. Unless otherwise specified, the term includes all materials to which a liquid adheres.

[0126] Although an example of an embodiment has been described above, the present invention is not limited to the above embodiment. That is, various modifications and improvements are possible within the scope of the present invention.

[0127] The embodiments also include a liquid ejection method. For example, the liquid ejection method is a liquid ejection method using a liquid ejection device that records liquid dots on a medium using an interlaced recording method, wherein the liquid ejection device ejects the liquid from each of a plurality of nozzles using a head, moves the head and the medium relative to each other in the main scanning direction and the sub-scanning direction intersecting the main scanning direction using a moving mechanism, changes the inclination of the head relative to the medium using a variable mechanism, controls the recording by the liquid ejection device using a control unit, and moves the head and the medium relative to each other in the main scanning direction when the inclination of the head is set to at least a first angle and a second angle using the inclination variable mechanism, the distance between adjacent nozzles along the sub-scanning direction is a first distance when the inclination of the head is set to the first angle, and a second distance different from the first distance when the inclination of the head is set to the second angle. With such a liquid ejection method, the same effects as the liquid ejection device 1000 described above can be obtained.

[0128] Each function of the embodiment can be realized by one or more processing circuits. Hereinafter, "processing circuit" as used herein includes processors programmed to execute each function by software, such as processors implemented by electronic circuits, as well as devices such as ASICs (Application Specific Integrated Circuits), DSPs (digital signal processors), FPGAs (field programmable gate arrays), and conventional circuit modules designed to execute the functions described above. [Explanation of Symbols]

[0129] 1 carriage 2 connectors 10 Housing 11 supply ports 12 Collection Ports 70 Head Unit 72 X-direction drive unit 82 Y-direction drive unit 92 Z-direction drive unit 100. Recorded material (an example of a medium) 101 X-axis rail 102 Y-axis rail 103 Z-axis rail 110 Moving mechanism 111 Reversal position 112 Recording start standby position 120 Tilt Variable Mechanism 121 Head rotation drive unit 121a Shaft 151, 152, 153 dots 200 supply units 230 Compressor 300 heads 310 Discharge Module 311 Nozzle Plate 321, N2~N8 nozzle 322 Flow Channel 324 Piezoelectric element 500 Control Unit 501 Storage section 502 Display section 503 Control Panel 1000 liquid dispensing device X direction, main scanning direction Y direction Sub-scanning direction A, B, C Dot pattern areas F Line feed amount Dy Dot Pitch K Interlace count N number N1 Standard Nozzle R Nozzle pitch along the alignment direction Nozzle pitch along the Rx X direction Nozzle pitch along the Ry and Y directions S1 plane T-scan count θ angle [Prior art documents] [Patent Documents]

[0130] [Patent Document 1] Japanese Patent Publication No. 2002-113849

Claims

1. A liquid dispensing device that records liquid dots onto a medium using an interlaced recording method, A head that discharges the liquid from each of multiple nozzles, A movement mechanism for moving the head and the medium relative to each other in the main scanning direction and the sub-scanning direction intersecting the main scanning direction, A tilt-variable mechanism for changing the tilt of the head relative to the medium, The system includes a control unit that controls the recording of the liquid onto the medium by the liquid dispensing device, The control unit moves the head and the medium relative to each other in the main scanning direction when the tilt of the head is set to either a first angle or a second angle by the tilt variable mechanism. The distance between adjacent nozzles along the aforementioned sub-scanning direction is a first distance when the head is tilted to the first angle, and a second distance different from the first distance when the head is tilted to the second angle. The moving mechanism performs a multiple operation consisting of relative movement of the head and the medium in the main scanning direction and relative movement of the head and the medium in the sub-scanning direction. The amount of relative movement per step in the multiple relative movements in the aforementioned sub-scanning direction is the same for all of the relative movements in the aforementioned sub-scanning direction. A liquid dispensing device wherein the second interval is two or more odd multiples of the first interval.

2. A liquid dispensing method using a liquid dispensing device that records liquid dots on a medium using an interlaced recording method, wherein the liquid dispensing device is The head causes the liquid to be discharged from each of the multiple nozzles. The moving mechanism moves the head and the medium relative to each other in the main scanning direction and the sub-scanning direction intersecting the main scanning direction. The variable mechanism changes the tilt of the head relative to the medium, The control unit controls the recording by the liquid dispensing device. The control unit moves the head and the medium relative to each other in the main scanning direction when the tilt of the head is set to either a first angle or a second angle by the tilt variable mechanism. The distance between adjacent nozzles along the aforementioned sub-scanning direction is a first distance when the head is tilted to the first angle, and a second distance different from the first distance when the head is tilted to the second angle. The moving mechanism performs a multiple operation consisting of relative movement of the head and the medium in the main scanning direction and relative movement of the head and the medium in the sub-scanning direction. The amount of relative movement per step in the multiple relative movements in the aforementioned sub-scanning direction is the same for all of the relative movements in the aforementioned sub-scanning direction. A liquid dispensing method wherein the second interval is two or more odd multiples of the first interval.

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