Liquid discharge device, liquid discharge system, liquid discharge method and program

Abstract

To provide a liquid discharge device that can improve productivity.SOLUTION: A liquid discharge device comprises: a plurality of nozzle rows NL1-NL4 respectively having a plurality of nozzles arranged in a first direction, which is arranged at different positions in a second direction crossing the first direction; and a control part that controls an operation of discharging liquid droplets discharged from the nozzles, by supplying a driving signal. The driving signal has a single pulse waveform in one period. The control part controls the operation of discharging so that the plurality of nozzle rows NL1-NL4 respectively discharge different discharge amounts of liquid droplets.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to a liquid ejection device, a liquid ejection system, a liquid ejection method, and a program. [Background technology]

[0002] As a liquid ejection device, an inkjet image recording device that ejects ink is known. The inkjet image recording device is equipped with a recording head that ejects ink. In the inkjet image recording device, the ejection amount of ink ejected from the recording head is controlled by a drive waveform supplied to a drive device of the recording head (for example, see Patent Document 1). The recording head can eject small droplets (small dots), medium droplets (medium dots), and large droplets (large dots) with different ejection amounts, for example, by using a drive waveform in which a plurality of pulse waveforms are included in one drive waveform. Summary of the Invention [Problem to be solved by the invention]

[0003] However, in Patent Document 1, one drive waveform contains multiple pulse waveforms, which makes the waveform length (period) long, which may result in a failure to improve productivity in liquid ejection devices.

[0004] An object of the present disclosure is to provide a liquid ejection apparatus capable of improving productivity. [Means for solving the problem]

[0005] The liquid ejection device of the present disclosure is a plurality of nozzle rows each having a plurality of nozzles aligned in a first direction and arranged at different positions in a second direction intersecting the first direction; a control unit that controls the ejection operation of droplets ejected from the nozzle by supplying a drive signal; The drive signal has a single pulse waveform within one period, The control unit controls the ejection operation so that droplets are ejected in different amounts for each of the plurality of nozzle rows. Effect of the Invention

[0006] According to the present disclosure, it is possible to provide a liquid ejection apparatus capable of improving productivity. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a perspective view of an image forming unit of the liquid ejection device according to the first embodiment. [Diagram 2] 2 is a bottom view of the head unit in FIG. 1. [Diagram 3] 3 is a bottom view showing a nozzle plate of the recording head in FIG. 2. [Figure 4] FIG. 2 is a block diagram showing an example of a hardware configuration of the liquid ejection device. [Diagram 5] FIG. 11 is a waveform diagram showing a driving waveform according to a comparative example. [Figure 6] 5 is a schematic diagram showing a nozzle array according to a comparative example and an arrangement of droplets ejected onto a recording medium. FIG. [Figure 7] 5 is a waveform diagram showing a driving waveform supplied to a recording head. FIG. [Figure 8] 1 is a schematic diagram showing a print head according to a first embodiment and an arrangement of droplets ejected onto a print medium. [Figure 9] 10 is a schematic diagram showing a print head according to a second embodiment and the arrangement of droplets ejected onto a print medium. FIG. [Figure 10] 13 is a schematic diagram showing a print head according to a third embodiment and an arrangement of droplets ejected onto a print medium. FIG. [Figure 11] 13 is a flowchart showing a procedure of a liquid ejection method according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments will be described with reference to the accompanying drawings. In this specification and the drawings, substantially the same components are designated by the same reference numerals, and redundant description may be omitted.

[0009] [Liquid ejection device according to the first embodiment] FIG. 1 is a perspective view of an image forming unit 2 of a liquid ejection device 500 according to the first embodiment. The liquid ejection device 500 is, for example, an inkjet type image forming device that ejects ink (droplets) onto a recording medium 1. The image forming device is also called a recording device. In each drawing, arrows indicating mutually orthogonal X-axis, Y-axis, and Z-axis directions may be shown. The Y-axis direction is aligned with the transport direction C of the recording medium 1. The Z-axis direction is aligned with the up-down direction. The X-axis direction, Y-axis direction, and Z-axis direction may be other directions.

[0010] [Head unit] 1, the liquid ejection device 500 has an image forming section 2 including a head unit 17. The head unit 17 is equipped with four color head modules (head arrays) 20Y, 20M, 20C, and 20K, a drive control board 3, a flat cable 19, and an adjuster plate 18. Each of the head modules 20Y, 20M, 20C, and 20K has a plurality of recording heads 40.

[0011] The drive control board 3 is a rigid board that includes a circuit (drive waveform generating circuit) that generates a drive waveform for driving a piezoelectric element (pressure generating element) included in the recording head 40, and a circuit for generating an image data signal. The flat cable 19 electrically connects the drive control board 3 to each recording head 40. The adjuster plate 18 positions and fixes each of the multiple recording heads 40 with high precision. The recording heads 40 are also called liquid ejection heads.

[0012] Each of the recording heads 40 in the head modules 20Y, 20M, 20C, and 20K has a built-in piezoelectric element. In each of the recording heads 40, the piezoelectric element is driven based on a drive waveform and image data signals transmitted from the drive control board 3 to eject ink onto the recording medium 1. The recording medium 1 is, for example, paper. The nozzle surface of each of the recording heads 40 is supported on a platen, which is the lower surface of the adjuster plate 10, with a predetermined gap maintained, and thus the nozzle surface is supported with a predetermined gap maintained from the recording medium 1. The recording medium 1 is transported in the transport direction C.

[0013] FIG. 2 is a bottom view of the head unit 17 in FIG. 1. The head unit 17 shown in FIG. 2 includes an assembly of four head modules 20Y, 20M, 20C, and 20K. The four head modules 20Y, 20M, 20C, and 20K each eject a different ink (black, cyan, magenta, and yellow). The head module 20Y ejects yellow ink. The head module 20M ejects magenta ink. The head module 20C ejects cyan ink. The head module 20K ejects black ink.

[0014] Each head module 20Y, 20M, 20C, and 20K extends in the X-axis direction perpendicular to the transport direction C of the recording medium 1. By arraying the heads in this manner, a wide printing area width is ensured. The printing area width may be the width of the area in the X-axis direction where the head modules 20Y, 20M, 20C, and 20K are arranged.

[0015] The head module 20Y has a plurality of recording heads 40. The plurality of recording heads 40 are aligned in the X-axis direction. Similarly, the head modules 20M, 20C, and 20K each have a plurality of recording heads 40. The plurality of recording heads 40 included in each of the head modules 20M, 20C, and 20K are aligned in the X-axis direction.

[0016] The head unit 17 has a plurality of recording heads 40 arranged in a straight line. In the head unit 17, the plurality of recording heads 40 may be arranged alternately in the Y-axis direction. In addition, the head unit 17 is not limited to one having a plurality of recording heads 40, and may be one having one recording head 40.

[0017] [Nozzle row] Fig. 3 is a bottom view showing the nozzle plate 41 of the recording head 40 in Fig. 2. As shown in Fig. 3, the recording head 40 includes the nozzle plate 41. The nozzle plate 41 has a plurality of nozzle rows NL1 to NL4 formed therein. The nozzle plate 41 includes a nozzle surface 41a. The nozzle surface 41a is the bottom surface of the nozzle plate 41, and is the surface that faces the recording medium 1 in the Z-axis direction.

[0018] A large number of nozzles N are formed on the nozzle surface 41a of the recording head 40. The multiple nozzles N are aligned in the X-axis direction. The X-axis direction is an example of a first direction. Nozzle rows NL1 to NL4 include multiple nozzles N aligned in the X-axis direction. Nozzle row NL1 is an example of a first nozzle row. Nozzle row NL2 is an example of a second nozzle row. Nozzle N1 included in nozzle row NL1 is an example of a first nozzle. Nozzle N2 included in nozzle row NL2 is an example of a second nozzle. In the same recording head 40, droplets ejected from nozzles N (N1 to N4) included in nozzle rows NL1 to NL4 are ink of the same color.

[0019] The multiple nozzle rows NL1 to NL4 are arranged in parallel. The multiple nozzles N (N1 to N4) of the nozzle rows NL1 to NL4 arranged at the same position in the X-axis direction can land ink in the same resolution area of ​​the recording medium 1. The nozzles N (N1 to N4) print by ejecting ink onto the recording medium 1. When the multiple nozzles N (N1 to N4) are arranged at the same position in the X-axis direction, they are said to overlap.

[0020] For example, nozzle N1 (first nozzle) included in nozzle row NL1, nozzle N2 (second nozzle) included in nozzle row NL2, nozzle N3 (third nozzle) included in nozzle row NL3, and nozzle N4 (fourth nozzle) included in nozzle row NL4 are arranged in overlapping positions when viewed in the Y-axis direction (second direction).

[0021] The droplets discharged from the nozzles N1 to N4 may overlap on the recording medium 1. The droplets discharged from the nozzles N1 to N4 do not have to overlap on the recording medium 1.

[0022] The number and arrangement of the recording heads 40 may be changed as appropriate in the head unit 17. In the head unit 17, the color arrangement and the arrangement of the nozzle rows NL1 to NL4 may also be changed as appropriate.

[0023] In the same recording head 40, the droplets ejected from the nozzles N included in the nozzle rows NL1 to NL4 may be inks of different colors.

[0024] [Pressure generating element] FIG. 4 is a block diagram showing an example of a hardware configuration of the liquid ejection device 500. As shown in FIG. 4, the recording head 40 has a plurality of pressure generating elements 45Pa, 45Pb, 45Pc, ..., 45Px. A plurality of pressure chambers corresponding to a plurality of nozzles N are formed inside the recording head 40. For example, one pressure chamber is provided for one nozzle N. The plurality of pressure generating elements 45Pa, 45Pb, 45Pc, ..., 45Px are provided corresponding to the nozzles N and the pressure chambers. The pressure generating elements 45Pa, 45Pb, 45Pc, ..., 45Px increase the pressure of the ink in the pressure chamber. The ink in the pressure chamber is pressurized by the pressure generating elements 45Pa, 45Pb, 45Pc, ..., 45Px and ejected from the nozzle N. The pressure generating elements 45Pa, 45Pb, 45Pc, ..., 45Px include, for example, piezoelectric elements (piezo elements).

[0025] The pressure generating element 45Pa ejects liquid droplets from, for example, a nozzle N (N1) included in the nozzle row NL1. The pressure generating element 45Pb ejects liquid droplets from, for example, a nozzle N (N2) included in the nozzle row NL2. The pressure generating element 45Pc ejects liquid droplets from, for example, a nozzle N (N3) included in the nozzle row NL3. The pressure generating element 45d ejects liquid droplets from, for example, a nozzle N (N4) included in the nozzle row NL4. The pressure generating element 45Pa is an example of a first actuator. The pressure generating element 45Pb is an example of a second actuator.

[0026] [Hardware configuration of liquid ejection device] The liquid ejection device 500 includes a main control board 100, a printhead driver 210, and an image processing board 300. The printhead driver 210 is electrically connected to the printhead 40. The image processing board 300 includes an image processing section 310. The image processing section 310 processes image data and outputs the image data to the main control board 100.

[0027] The main control board 100 is equipped with a CPU 101, an FPGA 102, a RAM 103, and a ROM 104. CPU is an abbreviation for "Central Processing Unit." FPGA is an abbreviation for "field programmable gate array." RAM is an abbreviation for "Random Access Memory." ROM is an abbreviation for "Read Only Memory."

[0028] The CPU 101 controls the entire liquid ejection apparatus 500, and performs various operational controls while communicating with the FPGA .

[0029] The FPGA 102 includes a CPU control unit 111, a memory control unit 112, an I2C control unit 113, a sensor processing unit 114, a motor control unit 115, and a printhead control unit 116.

[0030] The CPU control unit 111 communicates with the CPU 101 and controls the operation of the CPU 101. The memory control unit 112 accesses the RAM 103 and the ROM 104 and controls the operation of the RAM 103 and the ROM 104. The I2C control unit 113 communicates with the NVRAM 105 and controls the operation of the NVRAM 105. The sensor processing unit 114 processes the various sensors 130. The motor control unit 115 controls the operation of the various motors 140. The printhead control unit 116 supplies head drive data and the like stored in the ROM 104 to the drive waveform generation circuits 217a, 217b, 217c, and 217x, and causes the drive waveforms to be generated in the drive waveform generation circuits 217a, 217b, 217c, and 217x.

[0031] [Recording head driver] The recording head driver 210 includes a plurality of driving waveform generating circuits 217a, 217b, 217c, ..., 217x. The number of the driving waveform generating circuits 217a, 217b, 217c, ..., 217x is the same as the number of the pressure generating elements 45Pa, 45Pb, 45Pc, ..., 45Px of the recording head 40. The recording head driver 210 includes a driver control unit 216 that controls the operation of the plurality of driving waveform generating circuits 217a, 217b, 217c, ..., 217x. The recording head driver 210 is an example of a control unit that controls the ejection operation of droplets ejected from the nozzles N.

[0032] The drive waveform generating circuit 217a generates a drive waveform for driving the pressure generating element 45Pa and supplies the drive waveform to the pressure generating element 45Pa. The drive waveform generating circuit 217b generates a drive waveform for driving the pressure generating element 45Pb and supplies the drive waveform to the pressure generating element 45Pb. The drive waveform generating circuit 217c generates a drive waveform for driving the pressure generating element 45Pc and supplies the drive waveform to the pressure generating element 45Pc. The drive waveform generating circuit 217d generates a drive waveform for driving the pressure generating element 45Pd and supplies the drive waveform to the pressure generating element 45Pd. The drive waveform generating circuit 217x generates a drive waveform for driving the pressure generating element 45Px and supplies the drive waveform to the pressure generating element 45Px.

[0033] [Driving waveform according to the comparative example] Next, a driving waveform according to a comparative example will be described with reference to Fig. 5. Fig. 5 is a waveform diagram showing a driving waveform P31 according to a comparative example. In Fig. 5, the horizontal axis represents the passage of time, and the vertical axis represents the potential.

[0034] The drive waveform P31 includes a plurality of pulse waveforms P11, P12, and P13. For example, the recording head driver according to the comparative example supplies the pulse waveform P11 to the recording head when ejecting a small droplet D11. The recording head driver according to the comparative example supplies the drive waveform P21 (pulse waveforms P11, P12) to the recording head when ejecting a medium droplet D21. The recording head driver according to the comparative example supplies the drive waveform P31 to the recording head when ejecting a large droplet D31. In the comparative example, four patterns can be selected: "no droplet ejection", "ejection of small droplet D11", "ejection of medium droplet D21", and "ejection of large droplet D31". The drive waveform P31 is also called, for example, a four-value waveform.

[0035] The driving waveform P31 according to the comparative example includes multiple pulse waveforms P11, P12, and P13, so the length (waveform length, period) of the driving waveform P31 becomes long, which limits the driving frequency. The waveform length is generally expressed in μs (microseconds), and the reciprocal of this is the upper limit of the driving frequency.

[0036] For example, when the waveform length is 20 μs, the upper limit of the drive frequency is 50 kHz. The higher the drive frequency, the faster the ejection from the recording head, and therefore the higher the productivity of the liquid ejection device. On the other hand, when the drive frequency is low, not only does the productivity decrease, but there is also no room for designing the drive waveform, and there is a possibility that the liquid ejection stability of the liquid ejection device cannot be ensured.

[0037] 6 is a schematic diagram showing a nozzle row according to a comparative example, and the arrangement of droplets ejected onto a recording medium. In the comparative example, small droplets D11, medium droplets D21, and large droplets D31 can be ejected from one nozzle N. In the comparative example, a drive waveform P31 is supplied to a pressure generating element corresponding to one nozzle N. An image is formed on the recording medium 1 by each nozzle N ejecting different types of droplets in the scanning direction.

[0038] [Driving waveform according to the embodiment] Next, the drive waveforms supplied to the recording head 40 will be described with reference to Fig. 7. Fig. 7 is a waveform diagram showing the drive waveforms P41, P51, P61, and P71 supplied to the recording head 40. The recording head driver 210 of the liquid ejection device 500 can use a plurality of binary (on / off) waveforms as shown in Fig. 7.

[0039] The drive waveform P41 is used when printing dot A (D41). The drive waveform P51 is used when printing dot B (D51). The drive waveform P61 is used when printing dot C (D61). The drive waveform P71 is used when printing dot D (D61). The drive waveform P51 is an example of a first drive signal supplied to the first actuator. The drive waveform P61 is an example of a second drive signal supplied to the second actuator.

[0040] The driving waveforms P41, P51, P61, and P71 have different single pulse waveforms. The driving waveforms P41, P51, P61, and P71 have one single pulse waveform per cycle. One cycle may be, for example, the length of time from when the potential becomes the reference potential Ve once until the potential becomes the reference potential Ve again.

[0041] The drive waveforms P41, P51, P61, and P71 do not have multiple pulse waveforms P11, P12, and P13 as in the drive waveform P31 according to the comparative example shown in Fig. 5, and therefore have shorter waveform lengths than the drive waveform P31 according to the comparative example. Therefore, when the drive waveforms P41, P51, P61, and P71 are applied, the upper limit of the drive frequency can be increased.

[0042] However, when the driving waveforms P41, P51, P61, and P71 are applied, one driving waveform does not include a waveform for ejecting multiple droplet types, so there is a risk of a deterioration in the image quality formed on the recording medium 1. Also, in the liquid ejection device 500, it is difficult to switch the driving waveform for ejecting droplets during image formation.

[0043] [Control of droplet ejection behavior] The recording head driver 210 shown in Fig. 4 is a control unit that controls the discharge operation of droplets discharged from the nozzles N. Fig. 8 is a schematic diagram showing the recording head 40 according to the first embodiment and the arrangement of droplets discharged onto the recording medium 1. As shown in Figs. 7 and 8, the droplets discharged from the recording head 40 include dot A (D41), dot B (D51), dot C (D61), and dot D (D71). The discharge volume of the droplets is greatest for dot A (D41), dot B (D51), dot C (D61), and dot D (D71), in that order.

[0044] The printhead driver 210 controls the ejection operation of the printhead 40 so that each of the nozzle rows NL1, NL2, NL3, and NL4 ejects a different amount of droplets. For example, dot A (D41) is ejected from nozzle row NL1. Dot B (D51) is ejected from nozzle row NL2. Dot C (D61) is ejected from nozzle row NL3. Dot D (D71) is ejected from nozzle row NL4.

[0045] The printhead driver 210 can eject dot A (D41), dot B (D51), dot C (D61), and dot D (D71) with different ejection amounts onto the print medium 1 in different resolution areas.

[0046] The printhead driver 210 can eject dot A (D41), dot B (D51), dot C (D61), and dot D (D71) with different ejection amounts in the same resolution area on the print medium 1. For example, the printhead driver 210 can eject dot C (D61) and dot D (D71) in the same resolution area. For example, the printhead driver 210 can eject dot A (D41) and dot C (D61) in the same resolution area.

[0047] [Functions and Effects of the Liquid Ejection Device According to the First Embodiment] The liquid ejection device 500 according to the first embodiment includes a plurality of nozzle rows NL1 to NL4, each having a plurality of nozzles N aligned in the X-axis direction (first direction) and arranged at different positions in the Y-axis direction (second direction) intersecting the X-axis direction, and a printhead driver (controller) 210 that controls the ejection operation of droplets ejected from the nozzles N by supplying a drive signal. The drive signal has a single pulse waveform within one period. The printhead driver 210 controls the ejection operation so that each of the nozzle rows NL1 to NL4 ejects droplets (dot A, dot B, dot C, dot D) of different ejection amounts.

[0048] According to such a liquid ejection device 500, since the driving waveform P31 including the plurality of pulse waveforms P11 to P13 is not used, the waveform length can be shortened. This can improve the productivity of the liquid ejection device 500. In the liquid ejection device 500, ejection stability can be ensured by shortening the waveform length of the driving waveform. Furthermore, an image can be formed by droplets of different ejection amounts by ejecting droplets of different ejection amounts from each of the plurality of nozzle rows NL1 to NL4.

[0049] In the liquid ejection device 500, the nozzle arrays NL1 to NL4 include a nozzle array (first nozzle array) NL1 including a plurality of nozzles (first nozzles) N1 aligned in the X-axis direction, and a nozzle array (second nozzle array) NL2 including a plurality of nozzles (second nozzles) N2 aligned in the X-axis direction and disposed at a position different from the nozzle array NL1 in the Y-axis direction. The printhead driver 210 supplies a drive waveform (first drive signal) P41 to a pressure generating element (first actuator) 45Pa that ejects dots A (droplets) from the plurality of nozzles N1, and supplies a drive waveform (second drive signal) P51 to a pressure generating element (second actuator) 45Pb that ejects dots B (droplets) from the plurality of nozzles N2. The drive waveforms P41 and P51 have single pulse waveforms that are different from each other. The drive waveforms P41, P51, P61, and P71 have single pulse waveforms that are different from each other in at least one of the pulse width and the maximum voltage.

[0050] According to the liquid ejection device 500, the drive waveforms P41, P51 have single pulse waveforms different from each other, so that the waveform length of the drive waveforms P41, P51 can be made shorter than the waveform length of the conventional drive waveform P31. This can improve the productivity of the liquid ejection device 500. According to the liquid ejection device 500, the waveform length can be shortened, so ejection stability can be ensured. By shortening the waveform length of the drive waveforms P41, P51, a degree of leeway in designing the drive waveforms can be ensured.

[0051] In the liquid ejection device 500, the nozzle arrays NL1 to NL4 include a nozzle array NL3 that is arranged at a different position in the Y-axis direction from the nozzle arrays NL1 and NL2 and includes a plurality of nozzles N3 aligned in the X-axis direction, and a nozzle array NL4 that is arranged at a different position in the Y-axis direction from the nozzle arrays NL1 to NL3 and includes a plurality of nozzles N4 aligned in the X-axis direction. The printhead driver 210 supplies a drive waveform P61 to the pressure generating element 45Pc that ejects dots C from the nozzles N2, and supplies a drive waveform P71 to the pressure generating element 45Pd that ejects dots D from the nozzles N4. The drive waveforms P41, P51, P61, and P71 have single pulse waveforms that are different from each other in at least one of the pulse width and the maximum voltage.

[0052] According to the liquid ejection device 500, the drive waveforms P41, P51, P61, and P71 have single pulse waveforms different from each other, so that the waveform length of the drive waveforms P41, P51, P61, and P71 can be made shorter than the waveform length of the conventional drive waveform P31. This can improve the productivity of the liquid ejection device 500. According to the liquid ejection device 500, the waveform length can be shortened, so that ejection stability can be ensured. By shortening the waveform length of the drive waveforms P41, P51, P61, and P71, it is possible to ensure a margin in designing the drive waveforms. In the liquid ejection device 500, the waveform length of the drive waveforms P41, P51, P61, and P71 can be shortened, so that a time for a meniscus to be formed from the ejection of a droplet to the ejection of the next droplet in the same nozzle N can be ensured. Therefore, according to the liquid ejection device 500, ejection stability can be ensured.

[0053] In the liquid ejection device 500, the drive waveforms (first drive signal and second drive signal) P41, P51, P61, and P71 have one single pulse waveform per period. This allows the waveform lengths of the drive waveforms P41, P51, P61, and P71 to be shortened, improving productivity and ensuring ejection stability. In the liquid ejection device 500, one type of droplet can be ejected using each of the drive waveforms P41, P51, P61, and P71. In the liquid ejection device 500, dot A (D41) can be ejected using the drive waveform P41, dot B (D51) can be ejected using the drive waveform P51, dot C (D61) can be ejected using the drive waveform P61, and dot D (D71) can be ejected using the drive waveform P71.

[0054] In the liquid ejection device 500, dots A ejected from the multiple nozzles N1, dots B ejected from the multiple nozzles N2, dots C ejected from the multiple nozzles N3, and dots D ejected from the multiple nozzles N4 are ink of the same color. This allows ink of the same color to be ejected from the nozzles N1 to N4 of the multiple nozzle rows NL1 to NL4 that are arranged at different positions in the Y-axis direction.

[0055] Furthermore, in the liquid ejection device 500, the multiple nozzles N1 to N4 are arranged at positions where they overlap each other when viewed in the Y-axis direction. In other words, the multiple nozzles N1 to N4 are arranged at the same position in the X-axis direction. This makes it possible to eject multiple dots A, B, C, and D with different ejection amounts in the same resolution area on the recording medium 1.

[0056] Furthermore, in the liquid ejection device 500, the recording head driver 210 controls the ejection operation so that the dot A ejected from the nozzle N1, the dot B ejected from the nozzle N2, the dot C ejected from the nozzle N3, and the dot D ejected from the nozzle N4 overlap on the recording medium 1. The liquid ejection device 500 can improve image quality by ejecting droplets of different ejection amounts onto the same resolution area. The liquid ejection device 500 can appropriately select the dots A, B, C, and D to be overlapped. This can further improve image quality.

[0057] According to the liquid ejection device 500, a plurality of dots A, B, C, and D can be overlapped on the recording medium 1, so the amount of dots A, B, C, and D ejected from the nozzle N at one time may be smaller than in the past. The liquid ejection device 500 may eject dots A, B, C, and D that are smaller than in the past. In this case, by keeping the reference potential Ve in the drive waveforms P41, P51, P61, and P71 low, the load on the pressure generating element 45P can be reduced.

[0058] Furthermore, in the liquid ejection device 500, the multiple nozzle rows NL1 to NL4 are formed in the same recording head 40. This makes it possible to arrange the multiple nozzle rows NL1 to NL4 that eject droplets of different ejection amounts in one recording head 40.

[0059] [Liquid ejection device according to the second embodiment] Next, a liquid ejection device according to a second embodiment will be described with reference to FIG. 9. FIG. 9 is a schematic diagram showing the arrangement of the recording heads 40A and 40B according to the second embodiment and the liquid droplets ejected onto the recording medium 1. The liquid ejection device 500 according to the second embodiment differs from the liquid ejection device 500 according to the first embodiment in that the nozzle rows NL11-NL14 and NL21-N24 that eject dots A (D41), B (D51), C (D61), and D (D71) are arranged separately in the multiple recording heads 40A and 40B. In the description of the second embodiment, the same description as in the first embodiment will be omitted. The recording heads 40A and 40B may have the same configuration as the recording head 40.

[0060] The head unit 17 of the liquid ejection device 500 according to the second embodiment includes a plurality of recording heads 40A and 40B. The recording heads 40A and 40B are arranged side by side in the Y-axis direction. The recording head 40A has a plurality of nozzle rows NL11 to NL14. The recording head 40B has a plurality of nozzle rows NL21 to NL24.

[0061] The nozzle row NL11 of the recording head 40A ejects a dot A (D41). The nozzle row NL12 of the recording head 40A ejects a dot C (D61). The nozzle row NL21 of the recording head 40B ejects a dot B (D51). The nozzle row NL24 of the recording head 40B ejects a dot D (D71).

[0062] The nozzle rows NL11 and NL12 of the recording head 40A and the nozzle rows NL21 and NL24 of the recording head 40B eject ink of the same color.

[0063] Furthermore, the nozzle row NL13 of the recording head 40A ejects a dot A (D41). The nozzle row NL14 of the recording head 40A ejects a dot C (D61). The nozzle row NL22 of the recording head 40B ejects a dot B (D51). The nozzle row NL23 of the recording head 40B ejects a dot D (D71).

[0064] The nozzle rows NL13 and NL14 of the recording head 40A and the nozzle rows NL22 and NL23 of the recording head 40B eject ink of the same color. The nozzle rows NL13 and NL14 of the recording head 40A and the nozzle rows NL22 and NL23 of the recording head 40B eject ink of a different color than the nozzle rows NL11 and NL12 of the recording head 40A and the nozzle rows NL21 and NL24 of the recording head 40B.

[0065] The drive waveform generating circuits 217a, 217b, 217c, ..., 217x of the recording head driver 210 generate drive waveforms P41, P51, P61, and P71. The drive waveform generating circuits 217a, 217b, 217c, ..., 217x supply the drive waveforms P41, P51, P61, and P71 to the corresponding pressure generating elements 45Pa, 45Pb, 45Pc, ..., 45Px.

[0066] [Functions and Effects of the Liquid Ejection Device According to the Second Embodiment] The liquid ejection device according to the second embodiment also provides the same advantageous effects as the liquid ejection device according to the first embodiment.

[0067] In the liquid ejection device, the nozzle row NL11 that ejects dot A and the nozzle row NL21 that ejects dot B are formed in different recording heads 40A, 40B. Similarly, in the liquid ejection device, the nozzle row NL12 that ejects dot C and the nozzle row NL24 that ejects dot D are formed in different recording heads 40A, 40B. In this way, dots A, B, C, and D, which are ink of the same color, do not have to be ejected from the same recording head 40.

[0068] In the liquid ejection device, dots A, B, C, and D of the same color ink may be ejected from three or more recording heads 40.

[0069] [Liquid ejection device according to the third embodiment] Next, a liquid ejection device according to a third embodiment will be described with reference to FIG. 10. FIG. 10 is a schematic diagram showing the recording heads 40A and 40B according to the third embodiment and the arrangement of droplets ejected onto a recording medium 1. A liquid ejection device 500 according to the third embodiment differs from the liquid ejection device 500 according to the second embodiment in that the liquid ejection device 500 includes recording heads 40C and 40D instead of the recording heads 40A and 40B. The arrangement of the nozzle rows in the recording heads 40C and 40D differs from the arrangement of the nozzle rows in the recording heads 40A and 40B. In the description of the third embodiment, the same description as in the first and second embodiments will be omitted.

[0070] The head unit 17 of the liquid ejection device 500 according to the third embodiment includes a plurality of recording heads 40C and 40D. The recording heads 40C and 40D are arranged side by side in the Y-axis direction. The recording head 40C has a plurality of nozzle rows NL31 to NL34. The recording head 40D has a plurality of nozzle rows NL41 to NL44.

[0071] The nozzle rows NL31 and NL33 of the recording head 40C are arranged in a different position in the X-axis direction from the nozzle rows NL32 and NL34. The nozzle rows NL41 and NL43 of the recording head 40D are arranged in a different position in the X-axis direction from the nozzle rows NL42 and NL44.

[0072] The nozzle rows NL31 and NL33 of the recording head 40C are arranged in the same position in the X-axis direction as the nozzle rows NL41 and NL43 of the recording head 40D. When viewed along the Y-axis, the nozzles N included in the nozzle rows NL31, NL33, NL41, and NL43 are arranged in the same position.

[0073] The nozzle rows NL32 and NL34 of the recording head 40C are arranged in the same position in the X-axis direction as the nozzle rows NL42 and NL44 of the recording head 40D. When viewed along the Y-axis, the nozzles N included in the nozzle rows NL32, NL34, NL42, and NL44 are arranged in the same position.

[0074] The nozzle row NL31 of the recording head 40C ejects a dot A (D41). The nozzle row NL33 of the recording head 40C ejects a dot C (D61). The nozzle row NL41 of the recording head 40D ejects a dot B (D51). The nozzle row NL43 of the recording head 40D ejects a dot D (D71).

[0075] The nozzle rows NL31 and NL33 of the print head 40C and the nozzle rows NL41 and NL43 of the print head 40D eject ink of the same color.

[0076] The nozzle row NL32 of the recording head 40C ejects a dot A (D41). The nozzle row NL34 of the recording head 40C ejects a dot C (D61). The nozzle row NL42 of the recording head 40D ejects a dot B (D51). The nozzle row NL44 of the recording head 40D ejects a dot D (D71).

[0077] The nozzle rows NL32 and NL34 of the recording head 40C and the nozzle rows NL42 and NL44 of the recording head 40D eject ink of the same color. The nozzle rows NL32 and NL34 of the recording head 40C and the nozzle rows NL42 and NL44 of the recording head 40D eject ink of a different color than the nozzle rows NL31 and NL33 of the recording head 40C and the nozzle rows NL41 and NL43 of the recording head 40D.

[0078] [Functions and Effects of the Liquid Ejection Device According to the Third Embodiment] The liquid ejection device according to the third embodiment also provides the same advantageous effects as the liquid ejection device according to the first embodiment.

[0079] In the liquid ejection device, the recording head 40C includes a plurality of nozzle rows NL31, NL33 and nozzle rows NL32, NL34 arranged at different positions in the Y axis direction. In the recording head 40C, the nozzles N included in the plurality of nozzle rows NL31, NL33 arranged at different positions in the Y axis direction and the nozzles N included in the nozzle rows NL32, NL34 are shifted in the X axis direction.

[0080] In the liquid ejection device, the recording head 40D includes a plurality of nozzle rows NL41, NL43 and nozzle rows NL42, NL44 arranged at different positions in the Y axis direction. In the recording head 40D, the nozzles N included in the plurality of nozzle rows NL41, NL43 arranged at different positions in the Y axis direction and the nozzles N included in the nozzle rows NL42, NL44 are arranged to be shifted in the X axis direction.

[0081] In the liquid ejection device 500, the nozzles N in the recording heads 40C and 40D do not have to be the same in the X-axis direction.

[0082] [Liquid ejection method according to the fourth embodiment] Next, a liquid ejection method according to a fourth embodiment will be described with reference to Fig. 11. Fig. 11 is a flow chart showing the steps of the liquid ejection method according to the fourth embodiment. The liquid ejection method according to the fourth embodiment can be executed by, for example, the liquid ejection device 500 according to the first embodiment. In the description of the fourth embodiment, descriptions similar to those of the liquid ejection devices according to the first to third embodiments will be omitted.

[0083] 11, first, a dot A (D41) is discharged from the nozzle N1 of the nozzle row NL1 (step S11). In step S11, the drive waveform generating circuit 217a of the recording head driver 210 generates a drive waveform P41 and supplies the drive waveform P41 to the pressure generating element 45Pa. The pressure generating element 45Pa is driven in response to the drive waveform P41, causing the nozzle N1 to discharge a dot A (D41). The discharged dot A adheres to the recording medium 1.

[0084] Next, in the liquid ejection method, a dot B (D51) is ejected from the nozzle N2 of the nozzle row NL2 (step S12). In step S12, the drive waveform generating circuit 217b of the recording head driver 210 generates a drive waveform P51 and supplies the drive waveform P51 to the pressure generating element 45Pb. The pressure generating element 45Pb is driven in response to the drive waveform P51, causing the nozzle N2 to eject a dot B (D51). The ejected dot B adheres to the recording medium 1.

[0085] Next, in the liquid ejection method, a dot C (D61) is ejected from the nozzle N3 of the nozzle row NL3 (step S13). In step S13, the drive waveform generating circuit 217c of the recording head driver 210 generates a drive waveform P61 and supplies the drive waveform P61 to the pressure generating element 45Pc. The pressure generating element 45Pc is driven in response to the drive waveform P61, causing the nozzle N3 to eject a dot C (D61). The ejected dot C adheres to the recording medium 1.

[0086] Next, in the liquid ejection method, a dot D (D71) is ejected from the nozzle N4 of the nozzle row NL4 (step S14). In step S14, the drive waveform generating circuit 217d of the recording head driver 210 generates a drive waveform P71 and supplies the drive waveform P71 to the pressure generating element 45Pd. The pressure generating element 45Pd is driven in response to the drive waveform P71, causing the nozzle N4 to eject a dot D (D71). The ejected dot D adheres to the recording medium 1.

[0087] The liquid ejection method according to this embodiment is a liquid ejection method in which multiple nozzles N are arranged in the X-axis direction and liquid is ejected from nozzles N in multiple nozzle rows NL arranged at different positions in the Y-axis direction that intersects the X-axis direction, and different amounts of droplets are ejected from each of the multiple nozzle rows NL.

[0088] According to this liquid ejection method, the driving waveform P31 including the multiple pulse waveforms P11 to P13 is not used, and therefore the waveform length can be shortened. This can improve the productivity of the liquid ejection method. In the liquid ejection method, ejection stability can be ensured by shortening the waveform length of the driving waveform. Furthermore, an image can be formed by droplets of different ejection amounts by ejecting droplets of different ejection amounts from each of the multiple nozzle rows NL1 to NL4.

[0089] The above-described embodiment is presented as an example, and is not intended to limit the scope of the present invention. This embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. In addition, the embodiment and modifications of the embodiment are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

[0090] [Serial Head] The liquid ejection device 500 is not limited to one equipped with a line head in which the nozzle rows NL1 to NL4 extend in a direction intersecting the transport direction C of the recording medium 1. The liquid ejection device 500 may be one equipped with a serial head having a carriage on which the recording head 40 is mounted. The liquid ejection device 500 can move the carriage on which the recording head 40 is mounted in a direction intersecting the transport direction C. The nozzle rows NL1 to NL4 of the recording head 40 mounted on the carriage may be arranged along the transport direction C.

[0091] [Processing circuit] Each function of the above-described embodiments can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to execute each function by software, such as a processor implemented by an electronic circuit, and a device such as an ASIC (Application Specific Integrated Circuit), a DSP (digital signal processor), an FPGA (field programmable gate array), or a conventional circuit module designed to execute each function described above.

[0092] In the above embodiment, some or all of the processing in the printhead driver 210 may be executed by the main control board 100. Similarly, some of the processing by the main control board 100 may be executed by the printhead driver 210.

[0093] [Liquid discharge device] In the above embodiment, a liquid ejection device that is an image forming device has been described as an example of a liquid ejection device, but the liquid ejection device is not limited to an image forming device. The liquid ejection device is not limited to one that ejects ink as droplets, and may be one that ejects other liquids. The liquid ejection device may be a color printer that ejects ink of multiple colors, or a printer that ejects ink of a single color.

[0094] One aspect of the present invention may be as follows.

[0095] <1> a plurality of nozzle rows each having a plurality of nozzles aligned in a first direction and arranged at different positions in a second direction intersecting the first direction; a control unit that controls the ejection operation of droplets ejected from the nozzle by supplying a drive signal; The drive signal has a single pulse waveform within one period, The control unit controls the ejection operation so that droplets are ejected in different ejection amounts for each of the plurality of nozzle rows.

[0096] <2> The plurality of nozzle rows include a first nozzle row including a plurality of first nozzles aligned in the first direction; a second nozzle row that is arranged at a position different from that of the first nozzle row in the second direction and includes a plurality of second nozzles aligned in the first direction, The control unit is providing a first drive signal to a first actuator that causes droplets to be ejected from the first plurality of nozzles; providing a second drive signal to a second actuator that causes droplets to be ejected from the second plurality of nozzles; The first drive signal and the second drive signal have the single pulse waveform in which at least one of a pulse width and a maximum voltage is different from each other. <1> The liquid ejection device according to claim 1 .

[0097] <3> the droplets ejected from the first nozzles and the droplets ejected from the second nozzles are inks of the same color; <2> The liquid ejection device according to claim 1 .

[0098] <4> the plurality of first nozzles and the plurality of second nozzles are arranged at positions overlapping each other when viewed in the second direction; <2> or <3> The liquid ejection device according to claim 1 .

[0099] <5> The control unit is The method of controlling the ejection operation so that the droplets ejected from the first nozzles and the droplets ejected from the second nozzles overlap on a recording medium. <2> ~ <4> 13. The liquid ejection device according to claim 12,

[0100] <6> the first nozzle row and the second nozzle row are formed in the same recording head, <2> ~ <5> 13. The liquid ejection device according to claim 12,

[0101] <7> the first nozzle row and the second nozzle row are formed in different recording heads; <2> ~ <6> 13. The liquid ejection device according to claim 12,

[0102] <8> A recording head is provided. The above-mentioned ink ejection method, in which different types of ink are ejected from each of the plurality of recording heads <2> ~ <7> 13. The liquid ejection device according to claim 12,

[0103] <9> the recording head includes a plurality of nozzle rows arranged at different positions in the second direction, In the recording head, the nozzles included in the plurality of nozzle rows arranged at different positions in the second direction are arranged to be shifted in the first direction. <6> ~ <8> 13. The liquid ejection device according to claim 12,

[0104] <10> a liquid ejection device including a plurality of nozzle rows each having a plurality of nozzles aligned in a first direction and arranged at different positions in a second direction intersecting the first direction; a control unit that controls the ejection operation of droplets ejected from the nozzle by supplying a drive signal; The drive signal has a single pulse waveform within one period, The control unit controls the ejection operation so that droplets are ejected in different ejection amounts for each of the plurality of nozzle rows.

[0105] <11> A liquid ejection method using a liquid ejection device, comprising: The liquid ejection device includes: a plurality of nozzle rows each having a plurality of nozzles aligned in a first direction and arranged at different positions in a second direction intersecting the first direction; A control unit controls the ejection operation of droplets ejected from the nozzle by supplying a drive signal; The drive signal has a single pulse waveform within one period, The control unit controls the ejection operation so that droplets are ejected in different ejection amounts for each of the plurality of nozzle rows.

[0106] <12> A program for causing a computer to execute a process for controlling a droplet ejection operation in a liquid ejection device having a plurality of nozzle rows each having a plurality of nozzles aligned in a first direction and arranged at different positions in a second direction intersecting the first direction, the program comprising: A control unit controls the ejection operation of droplets ejected from the nozzle by supplying a drive signal; The drive signal has a single pulse waveform within one period, The control unit is a program that causes a computer to execute a process of controlling the ejection operation so that droplets are ejected in different ejection amounts for each of the plurality of nozzle rows. [Explanation of symbols]

[0107] 500 Liquid dispensing device 1 Recording medium 17 Head Unit 20Y, 20M, 20C, 20K Head Module 40, 40A, 40B Recording head 45Pa, 45Pb, 45Pc, 45Pd pressure generating element 210 Recording head driver (control unit) N Nozzle N1 Nozzle (1st nozzle) N2 nozzle (second nozzle) NL1~NL4 nozzle rows NL11~NL14 nozzle rows NL21~NL24 nozzle row NL31~NL34 nozzle row NL41~NL44 nozzle row XX axis direction (first direction) YY axis direction (second direction) ZZ axis direction [Prior art documents] [Patent documents]

[0108] [Patent Document 1] JP 2008-001084 A

Claims

1. a plurality of nozzle rows each having a plurality of nozzles aligned in a first direction and disposed at different positions in a second direction intersecting the first direction; a control unit that controls the ejection operation of droplets ejected from the nozzle by supplying a drive signal; The drive signal has a single pulse waveform within one period, The control unit controls the ejection operation so that droplets are ejected in different ejection amounts for each of the plurality of nozzle rows.

2. The plurality of nozzle rows include a first nozzle row including a plurality of first nozzles aligned in the first direction; a second nozzle row that is arranged at a position different from that of the first nozzle row in the second direction and includes a plurality of second nozzles aligned in the first direction, The control unit is providing a first drive signal to a first actuator that causes droplets to be ejected from the first plurality of nozzles; providing a second drive signal to a second actuator that causes droplets to be ejected from the second plurality of nozzles; The liquid ejection device according to claim 1 , wherein the first drive signal and the second drive signal have the single pulse waveform that is different from each other in at least one of a pulse width and a maximum voltage.

3. The liquid ejection device according to claim 2 , wherein the droplets ejected from the first nozzles and the droplets ejected from the second nozzles are ink of the same color.

4. The liquid ejection device according to claim 2 , wherein the first nozzles and the second nozzles are arranged so as to overlap each other when viewed in the second direction.

5. The control unit is The liquid ejection device according to claim 2 , wherein the ejection operation is controlled so that the droplets ejected from the first nozzles and the droplets ejected from the second nozzles overlap on the recording medium.

6. The liquid ejection apparatus according to claim 2 , wherein the first nozzle row and the second nozzle row are formed in the same recording head.

7. The liquid ejection apparatus according to claim 2 , wherein the first nozzle row and the second nozzle row are formed in different recording heads.

8. A recording head is provided. The liquid ejection apparatus according to claim 6 , wherein each of the plurality of recording heads ejects a different type of ink.

9. the recording head includes the plurality of nozzle rows arranged at different positions in the second direction, The liquid ejection device according to claim 8 , wherein in the recording head, the nozzles included in the plurality of nozzle rows arranged at different positions in the second direction are arranged to be shifted in the first direction.

10. a liquid ejection device including a plurality of nozzle rows each having a plurality of nozzles aligned in a first direction and arranged at different positions in a second direction intersecting the first direction; a control unit that controls the ejection operation of droplets ejected from the nozzle by supplying a drive signal; The drive signal has a single pulse waveform within one period, The control unit controls the ejection operation so that droplets are ejected in different ejection amounts for each of the plurality of nozzle rows.

11. A liquid ejection method using a liquid ejection device, comprising: The liquid ejection device includes: a plurality of nozzle rows each having a plurality of nozzles aligned in a first direction and disposed at different positions in a second direction intersecting the first direction; A control unit controls the ejection operation of droplets ejected from the nozzle by supplying a drive signal; The drive signal has a single pulse waveform within one period, The control unit controls the ejection operation so that droplets are ejected in different ejection amounts for each of the plurality of nozzle rows.

12. A program for causing a computer to execute a process for controlling a droplet ejection operation in a liquid ejection device including a plurality of nozzle rows each having a plurality of nozzles aligned in a first direction and arranged at different positions in a second direction intersecting the first direction, the program comprising: A control unit controls the ejection operation of droplets ejected from the nozzle by supplying a drive signal; The drive signal has a single pulse waveform within one period, The control unit is a program that causes a computer to execute a process of controlling the ejection operation so that droplets are ejected in different ejection amounts for each of the plurality of nozzle rows.

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