Liquid dispensing device, its control method and program

Abstract

To appropriately achieve high speed, high concentration and high resolution of recording.SOLUTION: Nozzles N of nozzle rows N1 and N3 and nozzles N of nozzle rows N2 and N4 overlap each other in a scan direction. Waveform signals supplied to the nozzle rows N1 and N3 in a high speed mode and a high concentration mode have different start timings t0 of a discharge period T, and the overlapping discharge periods T. Waveform signals supplied to the nozzle rows N2 and N4 have different start timings t0 of the discharge period T, and the overlapping discharge periods T. Dots D1 and D3 of ink discharged from the nozzles N overlapping in the scan direction in the nozzle rows N1 and N3 are alternately arranged in the scan direction on a sheet, dots D2 and D4 of ink discharged from the nozzles N overlapping in the scan direction in the nozzle rows N2 and N4 are alternately arranged in the scan direction on the sheet, and a set of the dots D1 and D3 and a set of the dots D2 and D4 are alternately arranged in a conveyance direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a liquid ejection device having a plurality of nozzle arrays, a control method therefor, and a program.

Background Art

[0002] Patent Document 1 discloses a liquid ejection device having a first nozzle array and a second nozzle array shifted in the direction in which the nozzles are arranged with respect to the position of the first nozzle array. When dots are formed on all pixels in the first mode (high-resolution mode), the first dots formed by the nozzles of the first nozzle array and the second dots formed by the nozzles of the second nozzle array are alternately formed in the direction in which the nozzles are arranged, and dot arrays of the first dots and dot arrays of the second dots are formed in the direction perpendicular to the direction in which the nozzles are arranged (the paper conveyance direction). When dots are formed on all pixels in the second mode (high-speed printing mode), a first dot array is formed such that the first dots are arranged in the direction in which the nozzles are arranged, and a second dot array in which the second dots are arranged in the direction in which the nozzles are arranged is formed so as to be shifted in the vertical direction from the first dot array, and the distance between the first dots in the vertical direction is larger than the distance between the first dots in the first mode.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the nozzles of the first nozzle array and the nozzles of the second nozzle array are shifted in the direction in which the nozzles are arranged (the first direction) and do not overlap in the conveyance direction (the second direction). Further, it is difficult to shorten the ejection period of the drive signal corresponding to each nozzle. Therefore, with the configuration of Patent Document 1, high-speed recording, high density, high resolution, etc. cannot be appropriately achieved.

[0005] The object of the present invention is to provide a liquid dispensing device, a control method therefor, and a program that can appropriately achieve high-speed recording, high concentration, high resolution, and the like.

[0006] According to a first aspect of the present invention, the invention comprises a first nozzle row, a second nozzle row, a third nozzle row, and a fourth nozzle row, which are nozzle rows including a plurality of nozzles arranged in a first direction; a moving mechanism for moving the plurality of nozzles and a recording medium relative to each other in a second direction intersecting the first direction; a plurality of elements for supplying discharge energy to each of the plurality of nozzles to discharge liquid; a drive circuit for supplying a drive signal based on a waveform signal to each of the plurality of elements; and a control unit, wherein the plurality of nozzles in the first nozzle row overlap each of the plurality of nozzles in the third nozzle row in the second direction, the plurality of nozzles in the second nozzle row do not overlap each of the plurality of nozzles in the first nozzle row in the second direction, and overlap each of the plurality of nozzles in the fourth nozzle row in the second direction, and the control unit provides the waveform signal for the nozzles in the first and third nozzle rows that overlap in the second direction, wherein the start timing of the discharge cycles differs from each other and the discharge cycles overlap each other. A liquid dispensing device is provided, characterized in that by supplying the waveform signal to the drive circuit, liquid dots discharged from nozzles overlapping in the second direction in the first and third nozzle rows are alternately arranged in the second direction on the recording medium, and by supplying the waveform signal for nozzles overlapping in the second direction in the second and fourth nozzle rows, wherein the start timing of the discharge cycles are different from each other and the discharge cycles overlap each other, to the drive circuit, liquid dots discharged from nozzles overlapping in the second direction in the second and fourth nozzle rows are alternately arranged in the second direction on the recording medium, and sets of liquid dots consisting of liquid dots discharged from nozzles overlapping in the second direction in the first and third nozzle rows and sets of liquid dots consisting of liquid dots discharged from nozzles overlapping in the second direction in the second and fourth nozzle rows are alternately arranged in an orthogonal direction perpendicular to the second direction.

[0007] According to a second aspect of the present invention, a control method for controlling a liquid discharge device comprising: a first nozzle row, a second nozzle row, a third nozzle row, and a fourth nozzle row, which are nozzle rows including a plurality of nozzles arranged in a first direction; a moving mechanism for moving the plurality of nozzles and a recording medium relative to each other in a second direction intersecting the first direction; a plurality of elements for supplying discharge energy to each of the plurality of nozzles to discharge liquid; and a drive circuit for supplying a drive signal based on a waveform signal to each of the plurality of elements, wherein the plurality of nozzles of the first nozzle row overlap each of the plurality of nozzles of the third nozzle row in the second direction, the plurality of nozzles of the second nozzle row do not overlap each of the plurality of nozzles of the first nozzle row in the second direction, and overlap each of the plurality of nozzles of the fourth nozzle row in the second direction, wherein the waveform signal for the nozzles overlapping in the second direction in the first nozzle row and the third nozzle row has different discharge cycle start timings and the discharge cycle is A control method is provided characterized by supplying the drive circuit with the waveform signals that overlap with each other, thereby arranging the liquid dots discharged from nozzles that overlap in the second direction in the first and third nozzle rows alternately in the second direction on the recording medium; supplying the drive circuit with the waveform signals for nozzles that overlap in the second direction in the second and fourth nozzle rows, where the start timing of the discharge cycles differs from each other and the discharge cycles overlap with each other, thereby arranging the liquid dots discharged from nozzles that overlap in the second direction in the second and fourth nozzle rows alternately in the second direction on the recording medium; and arranging sets of liquid dots discharged from nozzles that overlap in the second direction in the first and third nozzle rows alternately in an orthogonal direction perpendicular to the second direction.

[0008] According to a third aspect of the present invention, a liquid discharge device comprising: a first nozzle row, a second nozzle row, a third nozzle row, and a fourth nozzle row, which are nozzle rows including a plurality of nozzles arranged in a first direction; a moving mechanism for moving the plurality of nozzles and a recording medium relative to each other in a second direction intersecting the first direction; a plurality of elements for supplying discharge energy to each of the plurality of nozzles for discharging liquid; and a drive circuit for supplying a drive signal based on a waveform signal to each of the plurality of elements, wherein the plurality of nozzles of the first nozzle row overlap each of the plurality of nozzles of the third nozzle row in the second direction, the plurality of nozzles of the second nozzle row do not overlap each of the plurality of nozzles of the first nozzle row in the second direction, and overlap each of the plurality of nozzles of the fourth nozzle row in the second direction, wherein the waveform signal for nozzles overlapping in the second direction in the first nozzle row and the third nozzle row, wherein the start timing of the discharge cycles are different from each other and the discharge cycles overlap each other, A program is provided that functions as a means for supplying a drive circuit with a waveform signal for nozzles overlapping in the second direction in the first and third nozzle rows, wherein the start timing of the discharge cycles differs from each other and the discharge cycles overlap with each other, thereby causing the dots of liquid discharged from nozzles overlapping in the second direction in the second and fourth nozzle rows to function alternately in the second direction on the recording medium, and a means for arranging sets of liquid dots discharged from nozzles overlapping in the second direction in the first and third nozzle rows and sets of liquid dots discharged from nozzles overlapping in the second direction in the second and fourth nozzle rows alternately in an orthogonal direction perpendicular to the second direction. [Effects of the Invention]

[0009] According to the present invention, it is possible to appropriately achieve faster recording, higher resolution, higher density, and the like. [Brief explanation of the drawing]

[0010] [Figure 1] This is a plan view showing the overall configuration of a printer according to the first embodiment of the present invention. [Figure 2] Figure 1 is an explanatory diagram showing the arrangement of the nozzles on the print head and the arrangement of the ink dots ejected from each nozzle. [Figure 3] This is a cross-sectional view of the head shown in Figure 1. [Figure 4] This is a block diagram showing the electrical configuration of the printer in Figure 1. [Figure 5] This waveform diagram shows the four waveform data included in the FIRE waveform signal. [Figure 6] Figure 1 is a flowchart showing the program executed by the printer's control unit. [Figure 7] This diagram illustrates the process by which the waveform signal FIRE and the selection signal SIN are supplied from the control unit to the driver IC in normal mode. [Figure 8] This diagram illustrates the process by which the waveform signal FIRE and the selection signal SIN are supplied from the control unit to the driver IC in high-speed mode. [Figure 9] This diagram illustrates the process by which the waveform signal FIRE and the selection signal SIN are supplied from the control unit to the driver IC in high-concentration mode. [Figure 10] This is an explanatory diagram showing the process by which the waveform signal FIRE and the selection signal SIN are supplied from the control unit to the driver IC in the high-speed mode of a printer according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0011] <First Embodiment> As shown in Figure 1, the printer (liquid ejection device) 100 according to the first embodiment of the present invention comprises a head 10 having a plurality of nozzles N formed on its lower surface, a carriage 20 that holds the head 10, a scanning mechanism 30 that moves the carriage 20 in the scanning direction (direction perpendicular to the vertical direction), a platen 40 that supports the paper (recording medium) P from below, a transport mechanism 50 that transports the paper P in the transport direction (direction perpendicular to the scanning direction and the vertical direction), and a control unit 90.

[0012] The nozzles N are arranged diagonally with respect to the scanning direction and the transport direction. Specifically, the nozzles N are aligned in a first direction that intersects both the scanning direction (second direction) and the transport direction (orthogonal direction), forming four nozzle rows (first nozzle row N1, second nozzle row N2, third nozzle row N3, and fourth nozzle row N4). Each nozzle row N1 to N4 consists of multiple nozzles N aligned in the first direction.

[0013] More specifically, as shown in Figure 2, the nozzles N of the first nozzle row N1 and the nozzles N of the third nozzle row N3 overlap in the scanning direction, except for the nozzles N located at one end of the first direction in the first direction (upper end in Figure 2) in the first nozzle row N1 and the nozzles N located at the other end of the first direction in the third nozzle row N3 (lower end in Figure 2). The nozzles N of the second nozzle row N2 and the nozzles N of the fourth nozzle row N4 overlap in the scanning direction, except for the nozzles N located at one end of the first direction in the second nozzle row N2 (upper end in Figure 2) and the nozzles N located at the other end of the first direction in the fourth nozzle row N4 (lower end in Figure 2). The nozzles N of the second nozzle row N2 do not overlap in the scanning direction with either the nozzles N of the first nozzle row N1 or the nozzles N of the third nozzle row N3. The nozzles N of the fourth nozzle row N4 do not overlap in the scanning direction with either the nozzles N of the first nozzle row N1 or the nozzles N of the third nozzle row N3.

[0014] Nozzles N in each nozzle row N1 to N4 eject ink of the same color (for example, black).

[0015] In FIG. 2, for the sake of explanation, the nozzles N constituting each nozzle row N1 to N4 and the dots D1 to D4 of the ink ejected from the nozzles N of each nozzle row N1 to N4 are shown in solid black, slanted lines, solid lines, and broken lines for each row.

[0016] As shown in FIG. 1, the scanning mechanism 30 includes a pair of guides 31 and 32 that support the carriage 20 and a belt 33 connected to the carriage 20. The guides 31 and 32 and the belt 33 extend in the scanning direction. When the carriage motor 30m (see FIG. 4) is driven under the control of the control unit 90, the belt 33 runs, and the carriage 20 moves in the scanning direction along the guides 31 and 32. The scanning mechanism 30 relatively moves the nozzle N and the paper P in the scanning direction (second direction), which corresponds to the "moving mechanism" of the present invention.

[0017] The platen 40 is disposed below the carriage 20 and the head 10. The paper P is supported on the upper surface of the platen 40.

[0018] The conveyance mechanism 50 has two roller pairs 51 and 52. The head 10, the carriage 20, and the platen 40 are disposed between the roller pair 51 and the roller pair 52 in the conveyance direction. When the conveyance motor 50m (see FIG. 4) is driven under the control of the control unit 90, the roller pairs 51 and 52 rotate while sandwiching the paper P, and the paper P is conveyed in the conveyance direction.

[0019] As shown in FIG. 3, the head 10 includes a flow path unit 12 and an actuator unit 13.

[0020] A plurality of nozzles N open on the lower surface of the flow path unit 12. A plurality of pressure chambers 12p open on the upper surface of the flow path unit 12. Inside the flow path unit 12, a common flow path 12a communicating with an ink tank (not shown) and individual flow paths 12b for each nozzle N are formed. The individual flow path 12b is a flow path that extends from the outlet of the common flow path 12a through the pressure chamber 12p to the nozzle N.

[0021] The actuator unit 13 includes a metal diaphragm 13a positioned on the upper surface of the flow path unit 12 so as to cover a plurality of pressure chambers 12p, a piezoelectric layer 13b positioned on the upper surface of the diaphragm 13a, and a plurality of individual electrodes 13c positioned on the upper surface of the piezoelectric layer 13b so as to face each of the plurality of pressure chambers 12p.

[0022] The diaphragm 13a and the multiple individual electrodes 13c are electrically connected to the driver IC 14. The driver IC 14 corresponds to the "drive circuit" of the present invention, and maintains the potential of the diaphragm 13a at ground potential while changing the potential of the individual electrodes 13c. Specifically, the driver IC 14 generates a drive signal based on control signals from the control unit 90 (waveform signal FIRE and selection signal SIN, described later), and supplies this drive signal to the individual electrodes 13c via the signal line 14s at each ejection cycle (the cycle in which ink is ejected from the nozzle N). As a result, the potential of the individual electrodes 13c changes between a predetermined drive potential (VDD) and ground potential (0V) (see Figure 5). At this time, the portion (actuator 13x) sandwiched between each individual electrode 13c and each pressure chamber 12p in the diaphragm 13a and piezoelectric layer 13b deforms, changing the volume of the pressure chamber 12p, applying pressure (ejection energy) to the ink in the pressure chamber 12p, and ejecting ink from the nozzle N. The actuator 13x corresponds to the "element" of the present invention and is provided for each individual electrode 13c (i.e., each nozzle N), and can be independently deformed according to the potential supplied to the individual electrode 13c.

[0023] As shown in Figure 4, the control unit 90 includes a CPU (Central Processing Unit) 91, a ROM (Read Only Memory) 92, a RAM (Random Access Memory) 93, and an ASIC (Application Specific Integrated Circuit) 94. The ROM 92 stores programs and data for the CPU 91 and ASIC 94 to perform various controls. The RAM 93 temporarily stores data used by the CPU 91 and ASIC 94 when executing programs. The control unit 90 is connected to an external device (such as a personal computer) for communication purposes, and the CPU 91 and ASIC 94 execute recording processing based on recording commands received from the external device.

[0024] In the recording process, the ASIC94, in accordance with commands from the CPU91, drives the driver IC14, carriage motor 30m, and transport motor 50m, and alternately performs a transport operation in which the transport mechanism 50 transports a predetermined amount of paper P in the transport direction, and a scanning operation in which the scanning mechanism 30 moves the carriage 20 in the scanning direction while ejecting ink from the nozzle N. As a result, ink dots are formed on the paper P, and an image is recorded.

[0025] ASIC94 includes an output circuit 94a and a transfer circuit 94b.

[0026] The output circuit 94a generates a waveform signal FIRE and a selection signal SIN, and outputs these signals to the transfer circuit 94b at each ejection cycle. One ejection cycle is the time required for the paper P to move relative to the head 10 by a unit distance corresponding to the resolution of the image formed on the paper P, and corresponds to one pixel.

[0027] The waveform signal FIRE is a serial signal consisting of four waveform data F0 to F3 (see Figure 5) connected in series. Waveform data F0 (see Figure 5(a)) corresponds to a "zero (no ejection)" amount of ink ejected from nozzle N during one ejection cycle T, and maintains the potential of the individual electrode 13c at ground potential (0V). Waveform data F1 (see Figure 5(b)) corresponds to a "small" amount of ink ejected from nozzle N during one ejection cycle T, and includes one pulse that changes the potential of the individual electrode 13c between ground potential (0V) and drive potential (VDD), ejecting one drop of ink from nozzle N. Waveform data F2 (see Figure 5(c)) corresponds to a "medium" amount of ink ejected from nozzle N during one ejection cycle T, and includes two pulses that change the potential of the individual electrode 13c between ground potential (0V) and drive potential (VDD), ejecting two drops of ink from nozzle N. Waveform data F3 (see Figure 5(d)) corresponds to a "large" amount of ink ejected from nozzle N during one ejection cycle T. It includes four pulses that change the potential of the individual electrode 13c between ground potential (0V) and drive potential (VDD), causing four drops of ink to be ejected from nozzle N.

[0028] The waveform signal FIRE, by including four waveform data F0 to F3 (see Figure 5), represents four driving modes of the actuator 13x as a whole. The driving modes of the actuator 13x refer to the modes of deformation of the actuator 13x as described above, in response to changes in the potential of the individual electrodes 13c. The driving modes of the actuator 13x differ depending on the change in the potential of the individual electrodes 13c (i.e., for each waveform data F0 to F3). Depending on the driving mode of the actuator 13x, the volume of the pressure chamber 12p, the state of the meniscus formed in the nozzle N, and the amount of ink ejected from the nozzle N (including zero) differ.

[0029] Note that the waveform signal FIRE indicates the driving mode of actuator 13x and does not include waveform data for suppressing satellite droplets (for example, waveform data having multiple pulses arranged across two consecutive discharge cycles T).

[0030] The selection signal SIN is a serial signal containing selection data for selecting one of four waveform data F0 to F3 (see Figure 5), and is generated for each actuator 13x and each discharge cycle T based on the image data included in the recording command.

[0031] The transfer circuit 94b transfers (supplies) the waveform signal FIRE and the selection signal SIN received from the output circuit 94a to the driver IC 14. The transfer circuit 94b incorporates an LVDS (Low Voltage Differential Signaling) driver corresponding to each of the above signals, and transfers each signal to the driver IC 14 as a pulsed differential signal. The LVDS method is a method in which signals with opposite phases (H signal and L signal) are input to two signal lines, respectively. Compared to the single-ended method in which the signal is input to only one signal line, it is more resistant to noise and has the advantage of being able to transmit signals at low voltage with a smaller amplitude. Because the LVDS method can reduce the amplitude of the signal, the time required to switch between the H signal and the L signal can be shortened, and as a result, the signal frequency can be increased and data can be transmitted at high speed. In particular, the selection signal SIN contains selection data for the number of actuators 13x (number of nozzles N), so the amount of data can be enormous. By transferring this signal using the LVDS method, high-speed transmission is possible.

[0032] Next, referring to Figure 6, the program executed by the control unit 90 will be described. This process is repeatedly started, for example, while power is supplied to the printer 100.

[0033] The control unit 90 first determines whether or not it has received a record command from an external device (S1). If it has not received a record command (S1:NO), the control unit 90 terminates the program.

[0034] When a recording command is received (S1:YES), the control unit 90 determines whether the recording mode indicated by the recording command is the normal mode (S2).

[0035] The recording modes include normal mode, high-speed mode, and high-concentration mode. The high-speed mode and high-concentration mode correspond to the "first discharge mode" of the present invention, and the normal mode corresponds to the "second discharge mode" of the present invention.

[0036] If the control unit 90 determines that the recording mode is normal mode (S2: YES), it executes the recording process in normal mode (S3) and terminates the program.

[0037] If the control unit 90 determines that the recording mode is not the normal mode (S2: NO), it determines whether the recording mode is the high-speed mode (S4).

[0038] If the control unit 90 determines that the recording mode is high-speed mode (S4:YES), it executes the recording process in high-speed mode (S5) and terminates the program.

[0039] If the control unit 90 determines that the recording mode is not high-speed mode (S4: NO), it executes the recording process in high-density mode (S6) and terminates the program.

[0040] In normal mode, nozzle rows containing nozzles N without ejection defects are selected from the first nozzle row N1 and the third nozzle row N3, and nozzle rows containing nozzles N without ejection defects are selected from the second nozzle row N2 and the fourth nozzle row N4. For example, before the execution of this program, ejection defects are detected for all nozzles N, and the nozzle rows are selected based on the results of this detection. Figures 6 and 7 show an example in which ejection defects are detected in the nozzles N of the third nozzle row N3 and the fourth nozzle row N4, and no ejection defects are detected in the nozzles N of the first nozzle row N1 and the second nozzle row N2, resulting in the selection of the first nozzle row N1 and the second nozzle row N2. In this case, the control unit 90 transfers the waveform signal FIRE and the selection signal SIN for the first nozzle row N1 and the second nozzle row N2 from the transfer circuit 94b to the driver IC 14.

[0041] In Figure 7, time t0 is the point in time when the transfer circuit 94b receives the waveform signal FIRE and the selection signal SIN from the output circuit 94a, and corresponds to the start timing of the discharge cycle T. The transfer of the waveform signal FIRE starts at time t0. The transfer of the selection signal SIN starts after a delay time D has elapsed from time t0 and ends after the transfer of the waveform signal FIRE has finished. At the end of the transfer of the selection signal SIN, the selection signal SIN is latched (i.e., temporarily held and stored). After the transfer of the waveform signal FIRE and the selection signal SIN for one discharge cycle T has finished, the transfer of the waveform signal FIRE and the selection signal SIN for the next discharge cycle T has started.

[0042] In normal mode, by using either the first nozzle row N1 or the third nozzle row N3 (first nozzle row N1 in this example) and either the second nozzle row N2 or the fourth nozzle row N4 (second nozzle row N2 in this example), ink dots ejected from the nozzles N of the respective nozzle rows land on the paper P. Specifically, Figure 2 shows dots D1 to D4 from all nozzle rows N1 to N2, but in this example, dot D1 from the first nozzle row N1 and dot D2 from the second nozzle row N2 land on the paper P.

[0043] In high-speed mode, all nozzle rows N1 to N4 are used. In this case, as shown in Figure 8, the control unit 90 transfers the waveform signal FIRE and the selection signal SIN for the first nozzle row N1 to the fourth nozzle row N4 from the transfer circuit 94b to the driver IC 14.

[0044] In Figure 8, the signals from the first nozzle row N1 and the third nozzle row N3 (waveform signal FIRE and selection signal SIN) are signals for nozzles N that overlap in the scanning direction in these two rows. The signals from the first nozzle row N1 and the third nozzle row N3 are configured so that their ejection cycles T are offset from each other, with different start timings t0 for the ejection cycle T, and overlapping ejection cycles T. When these signals are supplied to the driver IC 14, ink dots D1 and D3 ejected from nozzles N that overlap in the scanning direction in the first nozzle row N1 and the third nozzle row N3 are alternately arranged on the paper P in the scanning direction (see Figure 2).

[0045] In Figure 8, the signals from the second nozzle row N2 and the fourth nozzle row N4 (waveform signal FIRE and selection signal SIN) are signals for nozzles N that overlap in the scanning direction in these two rows. The signals from the second nozzle row N2 and the fourth nozzle row N4 are configured so that their ejection cycles T are offset from each other, with different start timings t0 for the ejection cycle T, and overlapping ejection cycles T. When these signals are supplied to the driver IC 14, ink dots D2 and D4 ejected from nozzles N that overlap in the scanning direction in the second nozzle row N2 and the fourth nozzle row N4 are alternately arranged on the paper P in the scanning direction (see Figure 2).

[0046] Furthermore, pairs consisting of dots D1 and D3, and pairs consisting of dots D2 and D4, are arranged alternately in the transport direction (see Figure 2).

[0047] In Figure 8, the signals from the first nozzle row N1 and the second nozzle row N2 have matching discharge cycles T, and their start timings t0 for the discharge cycle T are the same.

[0048] In high-speed mode (see Figure 8), the output period T of the signal supplied to the driver IC 14 is the same as in normal mode (see Figure 7). The output period Tx corresponding to two dots D1, D3 or D2, D4 aligned in the scanning direction is shorter in high-speed mode (see Figure 8) than in normal mode (see Figure 7).

[0049] In high-concentration mode, all nozzle rows N1 to N4 are used, similar to high-speed mode. In this case, as shown in Figure 9, the control unit 90 transfers the waveform signal FIRE and the selection signal SIN for the first nozzle row N1 to the fourth nozzle row N4 from the transfer circuit 94b to the driver IC 14.

[0050] In Figure 9, the signals from the first nozzle row N1 and the third nozzle row N3 (waveform signal FIRE and selection signal SIN) are signals for nozzles N that overlap in the scanning direction in these two rows. The signals from the first nozzle row N1 and the third nozzle row N3 are configured so that their ejection cycles T are offset from each other, with different start timings t0 for the ejection cycle T, and overlapping ejection cycles T. When these signals are supplied to the driver IC 14, ink dots D1 and D3 ejected from nozzles N that overlap in the scanning direction in the first nozzle row N1 and the third nozzle row N3 are alternately arranged on the paper P in the scanning direction (see Figure 2).

[0051] In Figure 9, the signals from the second nozzle row N2 and the fourth nozzle row N4 (waveform signal FIRE and selection signal SIN) are signals for nozzles N that overlap in the scanning direction in these two rows. The signals from the second nozzle row N2 and the fourth nozzle row N4 are configured so that their ejection cycles T are offset from each other, with different start timings t0 for the ejection cycle T, and overlapping ejection cycles T. When these signals are supplied to the driver IC 14, ink dots D2 and D4 ejected from nozzles N that overlap in the scanning direction in the second nozzle row N2 and the fourth nozzle row N4 are alternately arranged on the paper P in the scanning direction (see Figure 2).

[0052] Furthermore, pairs of ink dots D1 and D3 ejected from nozzles N that overlap in the scanning direction in the first nozzle row N1 and the third nozzle row N3, and pairs of ink dots D2 and D4 ejected from nozzles N that overlap in the scanning direction in the second nozzle row N2 and the fourth nozzle row N4 are alternately arranged in an orthogonal direction perpendicular to the second direction (see Figure 2).

[0053] In Figure 9, the signals from the first nozzle row N1 and the second nozzle row N2 have matching discharge cycles T, and their start timings t0 for the discharge cycle T are the same.

[0054] In high-density mode (see Figure 9), the output period T of the signal supplied to the driver IC 14 is longer than in normal mode (see Figure 7) and longer than in high-speed mode (see Figure 8). The output period Tx corresponding to two dots D1, D3 or D2, D4 aligned in the scanning direction is the same in high-density mode (see Figure 9) and normal mode (see Figure 7), with the high-density mode (see Figure 9) having a longer output period than the high-speed mode (see Figure 8).

[0055] In addition, in high-speed mode (see Figure 8) and high-concentration mode (see Figure 9), there may be waveform signals between the first nozzle row N1 and the third nozzle row N3, and between the second nozzle row N2 and the fourth nozzle row N4, where the discharge cycle T does not overlap, for example, at the start and end of the recording operation.

[0056] As described above, according to this embodiment, the nozzles N of the first nozzle row N1 and the nozzles N of the third nozzle row N3 overlap in the scanning direction, and the nozzles N of the second nozzle row N2 and the nozzles N of the fourth nozzle row N4 overlap in the scanning direction (see Figure 2). To achieve high-speed recording, when ink is dispensed from these overlapping nozzles N in the scanning direction, the ejection cycle T is kept the same as in the normal mode (Figure 7), as shown in the high-speed mode in Figure 8, but the start timing t0 of the ejection cycle T is shifted. This makes it possible to shorten the ejection cycle Tx corresponding to two dots D1, D3 or D2, D4 aligned in the scanning direction compared to the normal mode, thereby achieving high speed. To achieve high density recording, when ink is dispensed from these overlapping nozzles N in the scanning direction, the ejection cycle T is made longer than in the normal mode (Figure 7), as shown in the high-density mode in Figure 9, and the start timing t0 of the ejection cycle T is shifted. This makes it possible to dispense larger ink droplets than in the normal mode, thereby achieving high density. Furthermore, by arranging sets of dots D1 and D3 and sets of dots D2 and D4 alternately in the transport direction (see Figure 2), the recording resolution in the transport direction can be increased. Thus, according to this embodiment, faster recording, higher density, higher resolution, etc., can be appropriately achieved.

[0057] The control unit 90 can switch between normal mode, high-speed mode, and high-density mode (see Figure 6). In high-speed mode and high-density mode, all nozzle rows N1 to N4 are used, and a waveform signal FIRE is supplied between the first nozzle row N1 and the third nozzle row N3, and between the second nozzle row N2 and the fourth nozzle row N4, such that the start timing t0 of the ejection cycle T is different from each other and the ejection cycle T overlaps (see Figures 8 and 9). Dots D1 and D3 are arranged alternately on the paper P in the scanning direction, and dots D2 and D4 are arranged alternately on the paper P in the scanning direction. Sets of dots D1 and D3 and sets of dots D2 and D4 are arranged alternately in the transport direction (see Figure 2). On the other hand, in normal mode, one of the first nozzle row N1 and the third nozzle row N3, and one of the second nozzle row N2 and the fourth nozzle row N4 are used, and a waveform signal FIRE is supplied to the nozzle row(s) (see Figure 7). Ink dots ejected from the nozzles N of the nozzle row land on the paper P. By switching the discharge mode in this way, it is possible to appropriately achieve faster recording and address issues with non-discharging nozzles.

[0058] In normal mode, the control unit 90 supplies the driver IC 14 with a waveform signal FIRE for nozzles N in the first nozzle row N1 and third nozzle row N3 that do not have ejection defects, and for nozzles N in the second nozzle row N2 and fourth nozzle row N4 that do not have ejection defects. In this case, by ejecting ink from nozzles N that do not have ejection defects, deterioration of image quality can be suppressed.

[0059] In high-speed mode (see Figure 8), the ejection period T is the same as in normal mode (Figure 7), but the start timing t0 of the ejection period T is shifted. This allows the ejection period Tx corresponding to two dots D1, D3 or D2, D4 aligned in the scanning direction to be shorter than in normal mode, thereby achieving higher speed.

[0060] In high-concentration mode (see Figure 9), the ejection cycle T is made longer than in normal mode (Figure 7), and the start timing t0 of the ejection cycle T is shifted. This allows for the ejection of larger ink droplets than in normal mode, thereby achieving higher concentration.

[0061] The ejection cycle T in high-concentration mode (see Figure 9) is longer than the ejection cycle T in high-speed mode (see Figure 8). This allows for the ejection of larger ink droplets than in high-speed mode, thus achieving higher ink density.

[0062] <Second Embodiment> Next, a second embodiment of the present invention will be described.

[0063] In the first embodiment, in high-speed mode (see Figure 8), the start timing t0 of the discharge cycle T is the same for the first nozzle row N1 and the second nozzle row N2, and the start timing t0 of the discharge cycle T is the same for the third nozzle row N3 and the fourth nozzle row N4. In contrast, in the second embodiment, in high-speed mode (see Figure 10), the start timing t0 of the discharge cycle T is different for all nozzle rows N1 to N4.

[0064] In high-speed mode (see Figure 10), the control unit 90 causes the start timing t0 of the second nozzle row N2 to occur after the start timing t0 of the first nozzle row N1, the start timing t0 of the third nozzle row N3 to occur after the start timing t0 of the second nozzle row N2, and the start timing t0 of the fourth nozzle row N4 to occur after the start timing t0 of the third nozzle row N3.

[0065] Furthermore, the waveform signals FIRE for the first nozzle row N1, the second nozzle row N2, the third nozzle row N3, and the fourth nozzle row N4 do not overlap in time with each other. The waveform signal FIRE in this embodiment includes, for example, two waveform data F0 and F1 (see Figure 5), and is shorter than the waveform signal FIRE in the first embodiment (see Figure 8). The discharge period T in the high-speed mode of the second embodiment (see Figure 10) is longer than the discharge period T in the high-speed mode of the first embodiment (see Figure 8).

[0066] As described above, according to this embodiment, by making the start timing t0 of the discharge cycle T different for all nozzle rows N1 to N4, the power peak that occurs at the start timing t0 can be distributed over time. In turn, waveform distortion due to power concentration can be suppressed, and the number of power concentration suppression components (capacitors, etc.) can be reduced.

[0067] The power load increases when the waveform signal FIRE is transferred. In this embodiment, the above effects (suppression of waveform distortion due to power concentration and reduction of power concentration suppression components (capacitors, etc.)) can be more effectively achieved by shifting the transfer timing of the waveform signal FIRE.

[0068] <Variation> Although preferred embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various design modifications are possible as long as they are within the scope of the claims.

[0069] In the above-described embodiment (see Figure 2), the first nozzle row N1, the second nozzle row N2, the third nozzle row N3, and the fourth nozzle row N4 are arranged in the second direction in that order, but the order of the nozzle rows is not limited to this. For example, the first nozzle row N1, the third nozzle row N3, the second nozzle row N2, and the fourth nozzle row N4 may be arranged in the second direction in that order.

[0070] In the above-described embodiment, in the normal mode (second mode), a nozzle row containing nozzle N without discharge defects is selected from among the two nozzle rows N1, N3 or N2, N4, but is not limited thereto. For example, in the two nozzle rows N1, N3, one nozzle (the nozzle without discharge defects) may be selected for each row (i.e., for each pair of nozzles overlapping in the second direction) based on the presence or absence of discharge defects.

[0071] The signals supplied to the drive circuit are not limited to serial data, but may also be parallel data. Furthermore, in the above embodiment, the transfer circuit transfers the waveform signal and the selection signal to the drive circuit as differential signals, but is not limited to this.

[0072] In the above embodiment, the actuator 13x (element) is driven using a "push-and-shoot method" (a method in which the actuator 13x is held flat in advance, and at a predetermined timing, the actuator 13x is deformed into a convex shape toward the pressure chamber 12p, thereby reducing the volume of the pressure chamber 12p and causing ink to be ejected from the nozzle N). However, the invention is not limited to this, and a "pull-and-shoot method" (a method in which the volume of the pressure chamber 12p is increased once, and then after a predetermined time has elapsed, the volume of the pressure chamber 12p is returned to its original state, causing ink to be ejected from the nozzle N) may also be used. In the "pull-and-shoot method", when the volume of the pressure chamber 12p increases, a negative pressure wave is generated within the pressure chamber 12p, and then, at the timing when the negative pressure wave reverses and returns to the pressure chamber 12p as a positive pressure wave, the volume of the pressure chamber 12p is returned to its original state, generating a positive pressure wave within the pressure chamber 12p, and these pressure waves are superimposed. By superimposing such pressure waves, a large pressure can be applied to the ink in the pressure chamber 12p. In the "pull-drive method," waveform data F0 (see Figure 5(a)) maintains the potential of the individual electrode 13c at the drive potential (VDD). Waveform data F1~F3 (see Figures 5(b)~(d)) set the potential of the individual electrode 13c at the drive potential (VDD) at time 0, and then vary it between the drive potential (VDD) and the ground potential (0V).

[0073] The element is not limited to a piezoelectric element (actuator 13x) as in the embodiment described above, but may also be a thermal or electrostatic element.

[0074] The liquid discharged from the nozzle is not limited to ink, but may be a liquid other than ink (for example, a processing liquid that causes components in the ink to coagulate or precipitate).

[0075] The recording medium is not limited to paper, but may also be cloth, resin material, etc. Furthermore, the recording medium is not limited to a sheet, but may also be in the form of a block, etc.

[0076] In the embodiments described above (see Figures 1 and 2), the first direction (the direction in which the nozzles of each nozzle row are aligned) intersects both the second direction (scanning direction) and the orthogonal direction (conveying direction), but it may also be orthogonal to the second direction (scanning direction) and parallel to the orthogonal direction (conveying direction).

[0077] In the embodiments described above, the head is serial, but it may also be line-type. In the line-type configuration, the transport mechanism corresponds to the "moving mechanism" of the present invention. In this case, the main scanning direction corresponding to the scanning direction in Figure 1 may be designated as the "first direction" or "orthogonal direction" of the present invention, and the transport direction may be designated as the "second direction" of the present invention.

[0078] The present invention is also applicable to color printers equipped with four heads that eject inks of different colors from each other.

[0079] The present invention is not limited to printers, but can also be applied to facsimile machines, copiers, multifunction devices, etc. Furthermore, the present invention can also be applied to liquid dispensing devices used for purposes other than image recording (for example, liquid dispensing devices that dispense conductive liquid onto a substrate to form conductive patterns).

[0080] The program according to the present invention can be recorded on removable recording media such as flexible disks or fixed recording media such as hard disks and distributed, as well as distributed via communication lines. [Explanation of Symbols]

[0081] 13x Actuators (Elements) 14. Driver IC (Driver Circuit) 30 Scanning mechanism (movement mechanism) 90 Control Unit 100 Printers (Liquid Dispensing Devices) N Nozzle N1 First Nozzle Row N2 Second nozzle row N3 Third Nozzle Row N4 Fourth nozzle row P paper (recording medium) FIRE waveform signal SIN selection signal T Dispensing cycle t0 Discharge cycle start timing D1~D4 dots

Claims

1. A head having multiple nozzles arranged in a first direction, A moving mechanism for moving the head in a second direction intersecting the first direction, A transport mechanism that transports the recording medium in a transport direction intersecting both the first and second directions, Multiple elements that provide discharge energy to discharge liquid from each of the multiple nozzles, A drive circuit that supplies a drive signal based on a waveform signal to each of the aforementioned plurality of elements, It comprises a control unit and, The head has a first nozzle row, a second nozzle row, a third nozzle row, and a fourth nozzle row, which are nozzle rows containing the plurality of nozzles arranged in the first direction. The plurality of nozzles in the first nozzle row overlap with each of the plurality of nozzles in the third nozzle row when viewed from the second direction. The plurality of nozzles in the second nozzle row do not overlap with each of the plurality of nozzles in the first nozzle row when viewed from the second direction, and overlap with each of the plurality of nozzles in the fourth nozzle row when viewed from the second direction. The control unit, By supplying the waveform signals for nozzles in the first and third nozzle rows that overlap when viewed from the second direction, wherein the start timing of the discharge cycles are different from each other and the discharge cycles overlap, to the drive circuit, the liquid dots discharged from the nozzles in the first and third nozzle rows that overlap when viewed from the second direction are arranged alternately in the second direction on the recording medium. By supplying the waveform signals for nozzles that overlap in the second nozzle row and the fourth nozzle row when viewed from the second direction, wherein the start timing of the discharge cycles are different from each other and the discharge cycles overlap, to the drive circuit, the liquid dots discharged from the nozzles that overlap in the second nozzle row and the fourth nozzle row when viewed from the second direction are arranged alternately in the second direction on the recording medium. A liquid dispensing device characterized by arranging alternately in the transport direction a set of liquid dots consisting of liquid discharged from nozzles that overlap when viewed from the second direction in the first and third nozzle rows, and a set of liquid dots consisting of liquid discharged from nozzles that overlap when viewed from the second direction in the second and fourth nozzle rows.

2. The control unit, It is possible to switch between the first discharge mode and the second discharge mode. In the first discharge mode, By supplying the waveform signals for nozzles in the first and third nozzle rows that overlap when viewed from the second direction, wherein the start timing of the discharge cycles are different from each other and the discharge cycles overlap, to the drive circuit, the liquid dots discharged from the nozzles in the first and third nozzle rows that overlap when viewed from the second direction are arranged alternately in the second direction on the recording medium. By supplying the waveform signals for nozzles that overlap in the second nozzle row and the fourth nozzle row when viewed from the second direction, wherein the start timing of the discharge cycles are different from each other and the discharge cycles overlap, to the drive circuit, the liquid dots discharged from the nozzles that overlap in the second nozzle row and the fourth nozzle row when viewed from the second direction are arranged alternately in the second direction on the recording medium. Sets of liquid dots discharged from nozzles that overlap when viewed from the second direction in the first and third nozzle rows, and sets of liquid dots discharged from nozzles that overlap when viewed from the second direction in the second and fourth nozzle rows, are arranged alternately in the transport direction. In the second discharge mode, By supplying the waveform signal to the drive circuit for one of the nozzles that overlap when viewed from the second direction in the first nozzle row and the third nozzle row, the liquid dots ejected from that nozzle are made to land on the recording medium. The liquid dispensing device according to claim 1, characterized in that the waveform signal for one of the nozzles that overlap when viewed from the second direction in the second nozzle row and the fourth nozzle row is supplied to the drive circuit, thereby causing a dot of liquid discharged from that nozzle to land on a recording medium.

3. The control unit, In the second discharge mode, By supplying the waveform signal to the drive circuit for one of the nozzles in the first and third nozzle rows that overlap when viewed from the second direction and have no discharge defects, the liquid dots discharged from that nozzle are made to land on the recording medium. The liquid dispensing device according to claim 2, characterized in that the waveform signal is supplied to the drive circuit for one nozzle that does not have a dispensing defect among the nozzles that overlap when viewed from the second direction in the second nozzle row and the fourth nozzle row, thereby causing a dot of liquid dispensed from that nozzle to land on a recording medium.

4. The liquid dispensing apparatus according to claim 2, characterized in that the dispensing period of the waveform signal supplied by the control unit to the drive circuit in the first dispensing mode is the same length as the dispensing period of the waveform signal supplied by the control unit to the drive circuit in the second dispensing mode.

5. The liquid dispensing apparatus according to claim 2, characterized in that the dispensing period of the waveform signal supplied by the control unit to the drive circuit in the first dispensing mode is longer than the dispensing period of the waveform signal supplied by the control unit to the drive circuit in the second dispensing mode.

6. The first discharge mode includes a high-speed mode and a high-concentration mode. The liquid dispensing apparatus according to claim 2, characterized in that the discharge period of the waveform signal supplied by the control unit to the drive circuit in the high-concentration mode is longer than the discharge period of the waveform signal supplied by the control unit to the drive circuit in the high-speed mode.

7. The liquid dispensing apparatus according to any one of claims 1 to 6, characterized in that the control unit causes the start timing of the second nozzle row to occur after the start timing of the first nozzle row, the start timing of the third nozzle row to occur after the start timing of the second nozzle row, and the start timing of the fourth nozzle row to occur after the start timing of the third nozzle row.

8. The liquid dispensing apparatus according to claim 7, characterized in that the control unit supplies the waveform signals for the first nozzle row, the second nozzle row, the third nozzle row, and the fourth nozzle row to the drive circuit in such a manner that they do not overlap with each other in time.

9. A control method for controlling a liquid discharge device comprising: a head having a plurality of nozzles arranged in a first direction; a moving mechanism for moving the head in a second direction intersecting the first direction; a transport mechanism for transporting a recording medium in a transport direction intersecting both the first and second directions; a plurality of elements for supplying discharge energy to each of the plurality of nozzles to discharge liquid; and a drive circuit for supplying a drive signal based on a waveform signal to each of the plurality of elements, wherein the head has a first nozzle row, a second nozzle row, a third nozzle row, and a fourth nozzle row which are nozzle rows including the plurality of nozzles arranged in the first direction; the plurality of nozzles in the first nozzle row overlap with each of the plurality of nozzles in the third nozzle row when viewed from the second direction; the plurality of nozzles in the second nozzle row do not overlap with each of the plurality of nozzles in the first nozzle row when viewed from the second direction; and the plurality of nozzles in the fourth nozzle row overlap with each of the plurality of nozzles when viewed from the second direction; By supplying the waveform signals for nozzles in the first and third nozzle rows that overlap when viewed from the second direction, wherein the start timing of the discharge cycles are different from each other and the discharge cycles overlap, to the drive circuit, the liquid dots discharged from the nozzles in the first and third nozzle rows that overlap when viewed from the second direction are arranged alternately in the second direction on the recording medium. By supplying the waveform signals for nozzles that overlap in the second nozzle row and the fourth nozzle row when viewed from the second direction, wherein the start timing of the discharge cycles are different from each other and the discharge cycles overlap, to the drive circuit, the liquid dots discharged from the nozzles that overlap in the second nozzle row and the fourth nozzle row when viewed from the second direction are arranged alternately in the second direction on the recording medium. A control method characterized by arranging alternately in the transport direction a set of liquid dots consisting of nozzles that overlap when viewed from the second direction in the first and third nozzle rows, and a set of liquid dots consisting of nozzles that overlap when viewed from the second direction in the second and fourth nozzle rows.

10. A liquid discharge device comprising: a head having a plurality of nozzles arranged in a first direction; a moving mechanism for moving the head in a second direction intersecting the first direction; a transport mechanism for transporting a recording medium in a transport direction intersecting both the first and second directions; a plurality of elements for supplying discharge energy to each of the plurality of nozzles to discharge liquid; and a drive circuit for supplying a drive signal based on a waveform signal to each of the plurality of elements, wherein the head has a first nozzle row, a second nozzle row, a third nozzle row, and a fourth nozzle row, which are nozzle rows including the plurality of nozzles arranged in the first direction, the plurality of nozzles in the first nozzle row overlap with each of the plurality of nozzles in the third nozzle row when viewed from the second direction, the plurality of nozzles in the second nozzle row do not overlap with each of the plurality of nozzles in the first nozzle row when viewed from the second direction, and the plurality of nozzles in the fourth nozzle row overlap with each of the plurality of nozzles when viewed from the second direction, A means for supplying the waveform signals for nozzles that overlap in the first and third nozzle rows when viewed from the second direction, wherein the start timing of the discharge cycles are different from each other and the discharge cycles overlap, to the drive circuit, thereby arranging the liquid dots discharged from the nozzles that overlap in the first and third nozzle rows when viewed from the second direction alternately in the second direction on the recording medium. A means for supplying the waveform signals for nozzles that overlap in the second nozzle row and the fourth nozzle row when viewed from the second direction, wherein the start timing of the discharge cycles are different from each other and the discharge cycles overlap, to the drive circuit, thereby arranging the liquid dots discharged from the nozzles that overlap in the second nozzle row and the fourth nozzle row when viewed from the second direction alternately in the second direction on the recording medium, and Means for alternately arranging in the transport direction a set of liquid dots consisting of nozzles that overlap when viewed from the second direction in the first and third nozzle rows, and a set of liquid dots consisting of nozzles that overlap when viewed from the second direction in the second and fourth nozzle rows, A program characterized by being designed to function as such.

Images