Image recording device, image recording system, and program

Abstract

To improve the image quality of an image recorded by an image recording device.SOLUTION: An inkjet head has four nozzle arrays arranged in a scanning direction. Each nozzle array includes a plurality of nozzles arranged in a conveyance direction orthogonal to the scanning direction. While moving a carriage equipped with the inkjet head in the scanning direction or in a reverse scanning direction, ink is discharged from the nozzles of the four nozzle arrays toward a recording sheet S at a timing at which the positions in the scanning direction when discharging ink become the same, thereby discharging ink from the four nozzles whose positions in the conveyance direction in the four nozzle arrays are the same, onto a same impact region R1 of the recording sheet S. When one of the four nozzles is an abnormal nozzle, the ink discharge amount from at least one normal nozzle among the four nozzles is increased.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to an image recording device that records an image by ejecting liquid from a nozzle, an image recording system that includes the image recording device, and a program for controlling the image recording device. [Background technology]

[0002] As an example of an image recording device that records an image by ejecting liquid from nozzles, Patent Document 1 describes a printer that ejects ink from nozzles to print on paper, etc. In the printer described in Patent Document 1, the recording head has three color ink nozzle rows formed by arranging multiple nozzle openings that eject color inks in the sub-scanning direction, and the colors of ink ejected by the three color ink nozzle rows are different. Also in Patent Document 1, the recording head has three black ink nozzle rows formed by arranging multiple nozzle openings that eject black ink in the sub-scanning direction, and the spacing in the sub-scanning direction between the multiple nozzle openings is the same in each black ink nozzle row and each color ink nozzle row.

[0003] The printer of Patent Document 1 can print in two modes: a black-and-white printing mode, in which black ink is ejected from nozzle openings constituting three rows of black ink nozzles while the carriage carrying the recording head is moved in the main scanning direction, and a color printing mode, in which three color inks are ejected from nozzle openings constituting three rows of color ink nozzles while the carriage is moved in the main scanning direction. In the black-and-white printing mode, printing can be performed three times faster than in the color printing mode. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 1-216852 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, as described above, the number of nozzles ejecting black ink is greater than the number of nozzles ejecting each color ink, so that printing can be performed faster in black and white print mode than in color print mode. On the other hand, in Patent Document 1, although the number of nozzles ejecting black ink is greater than the number of nozzles ejecting each color ink, the image quality of the image recorded in black and white print mode is about the same as the image quality of the image recorded in color print mode.

[0006] An object of the present invention is to provide an image recording device capable of recording at higher image quality, an image recording system capable of recording at higher image quality, and a program that enables recording at higher image quality in an image recording device. [Means for solving the problem]

[0007] The image recording device of the present invention comprises a recording unit including a plurality of nozzles and ejecting the same type of liquid from the plurality of nozzles; a movement mechanism that moves one of the recording unit and the recording medium in a first direction relative to the other of the recording unit and the recording medium; a memory unit that stores nozzle information for each nozzle of the recording unit, indicating whether the nozzle is a normal nozzle that ejects liquid normally or an abnormal nozzle that ejects liquid abnormally; and a control unit, wherein N is an integer of 2 or more, and the plurality of nozzles include a first nozzle to an Nth nozzle that are arranged at different positions in the first direction, and the control unit controls the movement mechanism to move one of the recording unit and the recording medium in the first direction relative to the other of the recording unit and the recording medium, The recording unit is controlled to execute an ejection process in which liquid is ejected from at least some of the first to Nth nozzles at a timing when the positional relationship between the first nozzle and the recording medium in the first direction when ejecting liquid is the same for the first to Nth nozzles, where M is an (N-1) integer between 2 and N, and when the nozzle information indicates that the first nozzle is the abnormal nozzle and at least one Mth nozzle is the normal nozzle, the recording unit is controlled in the ejection process not to eject liquid from the first nozzle, and to increase the amount of liquid ejected from at least one of the Mth nozzles that is the normal nozzle compared to when the first nozzle is the normal nozzle.

[0008] The image recording system of the present invention comprises: an image recording device comprising a recording unit including a plurality of nozzles and ejecting the same type of liquid from the plurality of nozzles; a movement mechanism that moves one of the recording unit and the recording medium in a first direction relative to the other of the recording unit and the recording medium, where N is an integer of 2 or more and the plurality of nozzles include first to Nth nozzles arranged at different positions in the first direction; and a control device that controls the image recording device, wherein the image recording device or the control device comprises a memory unit that stores nozzle information for each nozzle of the recording unit, indicating whether it is a normal nozzle that ejects liquid normally or an abnormal nozzle that ejects liquid abnormally, and the control device controls the movement mechanism to move one of the recording unit and the recording medium relative to the recording unit and the recording medium. and controls the recording unit while moving the recording unit in the first direction relative to the recording medium, and executes a discharge process to discharge liquid from at least some of the first to Nth nozzles at timing when the positional relationship between the first nozzle and the recording medium in the first direction is the same for the first to Nth nozzles, where M is an (N-1) integer between 2 and N, and when the nozzle information indicates that the first nozzle is the abnormal nozzle and at least one Mth nozzle is the normal nozzle, controls the recording unit in the discharge process not to discharge liquid from the first nozzle, and increases the amount of liquid discharged from at least one of the Mth nozzles that is the normal nozzle compared to when the first nozzle is the normal nozzle.

[0009] The program of the present invention is a program for controlling an image recording device comprising: a recording unit including a plurality of nozzles and ejecting the same type of liquid from the plurality of nozzles; a movement mechanism that moves one of the recording unit and the recording medium in a first direction relative to the other of the recording unit and the recording medium; and a storage unit that stores nozzle information for each nozzle of the recording unit, indicating whether it is a normal nozzle that ejects liquid normally or an abnormal nozzle that ejects liquid abnormally, wherein N is an integer of 2 or more, and the plurality of nozzles include first to Nth nozzles that are arranged at different positions in the first direction, and the program causes a computer to control the movement mechanism to move one of the recording unit and the recording medium in the first direction relative to the other of the recording unit and the recording medium. and controls the recording unit while moving the recording medium to a position where the recording medium is in a normal state, and executes a discharge process to discharge liquid from at least some of the first to Nth nozzles at timing when the positional relationship between the first to Nth nozzles and the recording medium in the first direction is the same for the first to Nth nozzles, where M is an (N-1) integer between 2 and N, and when the nozzle information indicates that the first nozzle is the abnormal nozzle and at least one Mth nozzle is the normal nozzle, controls the recording unit in the discharge process not to discharge liquid from the first nozzle, and increases the amount of liquid discharged from at least one of the Mth nozzles that is the normal nozzle compared to when the first nozzle is the normal nozzle. [Effects of the Invention]

[0010] In the present invention, for first to Nth nozzles arranged at different positions in the first direction, liquid is ejected from at least some of the first to Nth nozzles at timings when the positional relationship between the nozzles and the recording medium in the first direction is the same when ejecting the liquid. As a result, the liquid ejected from the first to Nth nozzles lands on landing areas on the recording medium that are located at the same position in the first direction. This increases the proportion of the landing area that is covered with the landed liquid compared to when the same amount of liquid as the total amount of liquid ejected from the first to Nth nozzles is ejected onto the landing area from only one nozzle. This improves the quality of the image recorded on the recording medium.

[0011] Furthermore, in the present invention, when the first nozzle is abnormal and at least one of the Mth nozzles is normal, liquid is not ejected from the first nozzle, and the amount of liquid ejected from at least one of the Mth nozzles is increased compared to when the first nozzle is normal. This prevents a decrease in the proportion of the landing area covered by the landed liquid, and prevents a decrease in the quality of the printed image, even if the first nozzle is abnormal. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram of a printer according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating the arrangement of nozzles in an inkjet head. [Figure 3] 3A and 3B are diagrams for explaining electrodes arranged in a cap and a configuration for applying a voltage to the electrodes. [Figure 4] FIG. 1(a) is a diagram for explaining the signal output from the signal processing circuit when the nozzle is a normal nozzle, and FIG. 1(b) is a diagram for explaining the signal output from the signal processing circuit when the nozzle is an abnormal nozzle. [Figure 5] FIG. 2 is a block diagram showing the electrical configuration of the printer. [Figure 6] (a) is a diagram for explaining the timing of ink ejection from the nozzles that make up each nozzle row during an ejection scan in which the carriage is moved in the scanning direction, and (b) is a diagram for explaining the timing of ink ejection from the nozzles that make up each nozzle row during an ejection scan in which the carriage is moved in the reverse scanning direction. [Figure 7] 10 is a flowchart showing a process flow when a recording command is received. [Figure 8](a) is a diagram explaining the image data to be acquired, (b) is a diagram explaining the pixels to be assigned to nozzle row 9A, (c) is a diagram explaining the pixels to be assigned to nozzle row 9B, (d) is a diagram explaining the pixels to be assigned to nozzle row 9C, and (e) is a diagram explaining the pixels to be assigned to nozzle row 9D. [Figure 9] 8 is a flowchart showing the flow of the discharge amount correction process in FIG. 7. [Figure 10] 10A is a diagram for explaining the priority of nozzle rows, and FIG. 10B is a diagram for explaining how many stages the size of ink droplets can be increased. [Figure 11] (a) is a diagram for explaining the image that is recorded when there is no abnormal nozzle, (b) is a diagram for explaining the image that is recorded when there is an abnormal nozzle and recording is performed without performing the discharge amount correction process, and (c) is a diagram for explaining the image that is recorded when there is an abnormal nozzle and recording is performed after performing the discharge amount correction process. [Figure 12] 10 is a flowchart showing the flow of a discharge amount correction process in an example in which the discharge amounts from two or more nozzles are increased so as to be equal. [Figure 13] 10 is a flowchart showing the flow of a discharge amount correction process in an example in which the ink discharge amount from two or more nozzles is increased in order. [Figure 14] (a) is a diagram for explaining the priority of nozzle rows in an example in which two adjacent nozzle rows on either side of a target nozzle are set to the same priority, and (b) is a flowchart showing part of the flow of the ejection volume correction process in this example. [Figure 15] 14B is a flowchart showing the process flow from I onwards in FIG. [Figure 16] (a) is a flowchart showing the processing flow from II onwards in Figure 14(b), (b) is a flowchart showing the processing flow from III onwards in Figure 14(b), and (c) is a flowchart showing the processing flow from IV onwards in Figure 14(b). [Figure 17](a) is a flowchart showing the processing flow from V onwards in Figure 14(b), and (b) is a diagram to explain how much to increase the size of the ink droplets for two nozzles with priority 1 when they are not abnormal nozzles and the size of the ink droplets indicated by the data for the corresponding pixels is not extra-large. [Figure 18] 10A and 10B are diagrams illustrating an inkjet head in which the nozzle arrangement direction is tilted with respect to the transport direction. [Figure 19] 18(a) is a diagram illustrating an image recorded by a printer equipped with the inkjet head of FIG. 18 when there is no abnormal nozzle, FIG. 18(b) is a diagram illustrating an image recorded by a printer equipped with the inkjet head of FIG. 18 when there is an abnormal nozzle and recording is performed without performing the discharge amount correction process, and FIG. 18(c) is a diagram illustrating an image recorded by a printer equipped with the inkjet head of FIG. 18 when there is an abnormal nozzle and recording is performed after performing the discharge amount correction process. [Figure 20] FIG. 1 is a schematic diagram illustrating the configuration of an image recording system including a printer and a control device. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present disclosure will be described below.

[0014] <Overall printer configuration> As shown in Fig. 1, the printer 1 according to this embodiment includes a carriage 2, an inkjet head 4, a platen 5, transport rollers 6 and 7, and a maintenance unit 8. In this embodiment, the printer 1 corresponds to the "image recording device," and the inkjet head 4 corresponds to the "recording unit."

[0015] The carriage 2 is supported by two horizontally extending guide rails 11 and 12. In the following description, one end of the guide rails 11 and 12 is defined as the right side, and the other end of the guide rails 11 and 12 is defined as the left side, as shown in FIG. 1 . The carriage 2 is connected to a carriage motor 86 shown in FIG. 5 via a belt (not shown). When the carriage motor 86 is driven, the carriage 2 moves to the right or left along the guide rails 11 and 12. In this embodiment, the direction in which the carriage 2 moves to the left is defined as the scanning direction, and the direction in which the carriage 2 moves to the right is defined as the reverse scanning direction. In this embodiment, the carriage 2, the guide rails 11 and 12, the carriage motor 86, and the belts connecting the carriage 2 and the carriage motor 86 together correspond to a "movement mechanism." In this embodiment, the scanning direction or the reverse scanning direction corresponds to a "first direction."

[0016] The inkjet head 4 is mounted on a carriage 2. As shown in FIGS. 1 and 2, the direction perpendicular to the horizontal plane in which gravity acts is defined as the downward direction, and the direction opposite to the direction in which gravity acts is defined as the upward direction. The inkjet head 4 has four nozzle arrays 9A to 9D arranged on its lower nozzle surface 4a. Each of the four nozzle arrays 9A to 9D is formed by arranging a plurality of nozzles 10 at intervals of a length L in a transport direction perpendicular to the scanning direction. The four nozzle arrays 9A to 9D are aligned in the scanning direction. As a result, the positions of the nozzles 10 constituting the nozzle arrays in the scanning direction differ among the nozzle arrays 9A to 9D. Furthermore, the positions of the nozzles 10 constituting the nozzle arrays in the transport direction are the same among the four nozzle arrays 9A to 9D. Here, the positions of the nozzles 10 constituting the nozzle arrays in the transport direction being the same among the four nozzle arrays 9A to 9D do not necessarily have to be strictly the same, and may be slightly misaligned in the transport direction. For example, between any two of the four nozzle rows 9A to 9D, the positions of the nozzles 10 constituting the nozzle rows in the transport direction may be shifted by a length equal to or less than L / 2, which is half the length of the interval between the nozzles 10 in each nozzle row. In this embodiment, the transport direction corresponds to the "second direction."

[0017] The inkjet head 4 ejects black ink as a homogeneous liquid from a plurality of nozzles 10 constituting four nozzle rows 9A to 9D. The inkjet head 4 can selectively eject one of four types of ink droplets with different ink volumes from each nozzle 10: small droplets, medium droplets, large droplets, and extra-large droplets. Medium droplets have a larger ink volume than small droplets, large droplets have a larger ink volume than medium droplets, and extra-large droplets have a larger ink volume than large droplets. The inkjet head 4 is connected to an ink cartridge (not shown) via a tube (not shown) or the like, and black ink is supplied from the ink cartridge.

[0018] The platen 5 is disposed below the inkjet head 4 and faces the multiple nozzles 10. The platen 5 extends in the scanning direction and supports the recording paper S from below across the entire width of the recording paper S. The transport roller 6 is disposed upstream of the inkjet head 4 and the platen 5 in the transport direction. The transport roller 7 is disposed downstream of the inkjet head 4 and the platen 5 in the transport direction. The transport rollers 6 and 7 are connected to a transport motor 87 shown in FIG. 5 via gears (not shown). When the transport motor 87 is driven, the transport rollers 6 and 7 rotate and the recording paper S is transported in the transport direction.

[0019] The maintenance unit 8 includes a cap 71, a suction pump 72, and a waste liquid tank 73. The cap 71 is disposed to the right of the platen 5. When the carriage 2 is positioned at the maintenance position to the right of the platen 5, the plurality of nozzles 10 face the cap 71.

[0020] The cap 71 is connected to a cap lifting mechanism 88 shown in FIG. 5. When the cap lifting mechanism 88 is driven, the cap 71 moves up and down. When the carriage 2 is positioned at the maintenance position, where the plurality of nozzles 10 and the cap 71 face each other, the cap 71 is raised by the cap lifting mechanism 88, whereby the upper end of the cap 71 comes into close contact with the nozzle surface 4a, covering the plurality of nozzles 10. When the cap 71 is lowered, the plurality of nozzles 10 are not covered by the cap 71. Note that the cap 71 does not necessarily have to cover the plurality of nozzles 10 by coming into close contact with the nozzle surface 4a. For example, the cap 71 may cover the plurality of nozzles 10 by coming into close contact with a frame (not shown) or the like that is arranged around the nozzle surface 4a of the inkjet head 4.

[0021] The suction pump 72 is a tube pump or the like, and is connected to the cap 71 and the waste liquid tank 73. In the maintenance unit 8, when the suction pump 72 is driven in the above-mentioned capped state, it is possible to perform a so-called suction purge, which discharges ink from inside the inkjet head 4 through the multiple nozzles 10. The ink discharged by the suction purge is stored in the waste liquid tank 73.

[0022] 3, the maintenance unit 8 is provided with a discharge inspection section 20. The discharge inspection section 20 has an electrode 76, a high-voltage power supply circuit 77, a signal processing circuit 78, and a resistor 79.

[0023] The electrode 76 has a rectangular planar shape and is disposed within the cap 71. The electrode 76 is connected to a high-voltage power supply circuit 77 via a resistor 79. The high-voltage power supply circuit 77 applies a predetermined voltage, for example, approximately 600 V, to the electrode 76. Meanwhile, the inkjet head 4 is held at ground potential. This generates a potential difference between the inkjet head 4 and the electrode 76. A signal processing circuit 78 is connected to the electrode 76. The signal processing circuit 78 includes a differentiation circuit and outputs a signal corresponding to the voltage of the electrode 76. In this embodiment, the signal output from the signal processing circuit 78 is a voltage signal. However, the signal output from the signal processing circuit 78 may also be a current signal.

[0024] Furthermore, in this embodiment, after the capping is performed, a voltage is applied to the electrode 76 by the high-voltage power supply circuit 77, and the inkjet head 4 can be driven to eject ink from the nozzle 10 toward the electrode 76.

[0025] Here, in the above-mentioned cap state, when a predetermined voltage is applied to the electrode 76 by the high-voltage power supply circuit 77 and when no ejection drive is being performed, the voltage of the signal output from the signal processing circuit 78 is approximately the voltage V0 shown in Figures 4(a) and (b).

[0026] When ink is ejected from the nozzle 10 by the ejection drive, the ejected ink is charged due to the potential difference between the electrode 76 and the inkjet head 4. Therefore, as the charged ink approaches the electrode 76, the potential of the electrode 76 changes until the ink lands on the electrode 76. Then, after the charged ink lands on the electrode 76, the potential of the electrode 76 attenuates and returns to the potential before the ink was ejected.

[0027] As a result, when ink is normally ejected from the nozzle 10 by the ejection drive, the signal output from the signal processing circuit 78 rises from voltage V0 to a voltage equal to or higher than voltage V1, which is higher than voltage V0, as shown in Figure 4(a), then drops to a voltage equal to or lower than voltage V2, which is lower than voltage V0, and then repeats this rise and fall while attenuating, before returning to voltage V0.

[0028] On the other hand, if there is an abnormality in the nozzle 10 and the amount of ink ejected from the nozzle 10 by the ejection drive is less than normal, as shown in Figure 4(b), the change in the signal output from the signal processing circuit 78 is smaller than when ink is ejected normally from the nozzle 10. Here, the fact that the amount of ink ejected is less than when ink is ejected normally from the nozzle 10 also includes the case where ink is not ejected. When ink is not ejected from the nozzle 10 by the ejection drive, the signal output from the signal processing circuit 78 changes very little from voltage V0.

[0029] In this embodiment, the signal output from the signal processing circuit 78 differs depending on whether ink is ejected normally from the nozzle 10 when the nozzle is driven to eject ink. In other words, the signal output from the signal processing circuit 78 indicates whether the nozzle 10 is a normal nozzle that ejects ink normally, or an abnormal nozzle that is experiencing an abnormality in ink ejection.

[0030] In this embodiment, a predetermined voltage is applied to the electrode 76, the inkjet head 4 is held at ground potential, and the signal processing circuit 78 outputs a signal corresponding to the voltage of the electrode 76, but this is not limiting. Alternatively, the electrode 76 may be held at ground potential and a predetermined voltage may be applied to the inkjet head 4 to generate a potential difference between the electrode 76 and the inkjet head 4, and the signal processing circuit 78 may be connected to the inkjet head 4 and output a signal corresponding to the voltage of the inkjet head 4 when it is driven to eject ink.

[0031] <Printer electrical configuration> Next, the electrical configuration of the printer 1 will be described. As shown in Figure 5, the printer 1 is equipped with a control unit 80. The control unit 80 is made up of a CPU 81, ROM 82, RAM 83, flash memory 84, ASIC 85, etc. Note that CPU is an abbreviation for Central Processing Unit. ROM is an abbreviation for Read Only Memory. RAM is an abbreviation for Random Access Memory. ASIC is an abbreviation for Application Specific Integrated Circuit. The control unit 80 controls a carriage motor 86, inkjet head 4, transport motor 87, cap lifting mechanism 88, suction pump 72, high-voltage power supply circuit 77, signal processing circuit 78, etc.

[0032] The control unit 80 may be configured such that only the CPU 81 performs various processes, or such that only the ASIC 85 performs various processes, or such that the CPU 81 and the ASIC 85 work together to perform various processes. The control unit 80 may be configured such that one CPU 81 performs processes independently, or such that multiple CPUs 81 share the processes. The control unit 80 may be configured such that one ASIC 85 performs processes independently, or such that multiple ASICs 85 share the processes.

[0033] <Nozzle inspection> In the printer 1, the control unit 80 controls the printer 1 to inspect each of the multiple nozzles 10 of the inkjet head 4 to determine whether it is a normal nozzle or an abnormal nozzle. Specifically, in the printer 1, the control unit 80 controls the carriage motor 86, cap lifting mechanism 88, etc. to establish the cap state described above, and controls the high-voltage power supply circuit 77 to apply a voltage to the electrodes 76, causing the inkjet head 4 to perform ejection driving for each of the multiple nozzles 10. The control unit 80 then stores nozzle information in the memory 84 regarding whether a nozzle 10 is a normal nozzle or an abnormal nozzle, based on a signal output from the signal processing circuit 78 when ejection driving for each nozzle 10 has been performed. The printer 1 also inspects the nozzles 10 at appropriate times, such as at a predetermined time, every time a predetermined number of sheets of recording paper S have been recorded, or during the period from when a recording command (described later) is received until recording on the recording paper S is performed.

[0034] <Recording control> In the printer 1, the control unit 80 controls the carriage motor 86 to move the carriage 2 in the scanning direction or reverse scanning direction, while controlling the inkjet head 4 to perform an ejection scan to eject ink from multiple nozzles 10 toward the recording paper S, and controlling the transport motor 87 to perform a transport operation to transport the recording paper S in the transport direction, thereby recording an image on the recording paper S.

[0035] At this time, when the carriage 2 is moved in the scanning direction and when it is moved in the reverse scanning direction, the inkjet head 4 is caused to perform an ejection scan in which ink is ejected from the multiple nozzles 10. Then, as shown in FIG. 6(a), during an ejection scan in which the carriage 2 is moved in the scanning direction, ink is ejected from the multiple nozzles 10 constituting each of the nozzle arrays 9A to 9D at timings when the nozzles are positioned at the same time in the scanning direction. Also, as shown in FIG. 6(b), during an ejection scan in which the carriage 2 is moved in the reverse scanning direction, ink is ejected from the multiple nozzles 10 constituting each of the four nozzle arrays 9A to 9D at timings when the nozzles are positioned at the same time in the reverse scanning direction. That is, for each of the four nozzle arrays 9A to 9D, ink is ejected from the multiple nozzles 10 constituting each of the nozzle arrays at timings when the positional relationship between the multiple nozzles 10 constituting the nozzle array and the recording paper S is the same in both the scanning direction and the reverse scanning direction. In addition, the positions of the nozzle rows 9A to 9D in the scanning direction when ink is ejected from the multiple nozzles 10 that make up each nozzle row during an ejection scan in which the carriage 2 is moved in the scanning direction are different from the positions of the nozzle rows 9A to 9D in the reverse scanning direction when ink is ejected from the multiple nozzles 10 that make up each nozzle row during an ejection operation in which the carriage 2 is moved in the reverse scanning direction.

[0036] Alternatively, when the carriage 2 is moved in the scanning direction, ink may be ejected from the plurality of nozzles 10 to perform an ejection scan, and when the carriage 2 is moved in the reverse scanning direction, ink may not be ejected from the plurality of nozzles 10. Alternatively, when the carriage 2 is moved in the reverse scanning direction, ink may be ejected from the plurality of nozzles 10 to perform an ejection scan, and when the carriage 2 is moved in the scanning direction, ink may not be ejected from the plurality of nozzles 10.

[0037] Furthermore, in the printer 1, when a recording command instructing recording of an image on recording paper S is received, the control unit 80 performs the processing shown in the flowchart of Fig. 7, thereby causing the inkjet head 4 to record an image on recording paper S. For example, the control unit 80 receives the recording command when a user performs an operation to instruct recording of an image on recording paper S on an operation unit (not shown) provided in the printer 1 or on a PC (not shown) or the like connected to the printer 1. Here, in this embodiment, a program for causing the control unit 80 to perform the processing shown in the flowchart of Fig. 7 is stored in the ROM 82 or the like, and when the control unit 80 receives a recording command, it reads this program from the ROM 82 or the like and performs the processing shown in the flowchart of Fig. 7 based on this program.

[0038] The flowchart in Fig. 7 will be described in detail. The control unit 80 executes an image data acquisition process when it receives a recording command (S101). In the image data acquisition process, the control unit 80 acquires image data. For example, the recording command includes information instructing image data of an image to be recorded from image data stored in the memory 84 or the like, and when the control unit 80 receives a recording command as a result of an operation of an operation unit (not shown) of the printer 1, the control unit 80 acquires the image data from the memory 84 or the like based on this information. Also, for example, when a PC (not shown) connected to the printer 1 receives a recording command as a result of an operation of the PC, the PC transmits image data to the printer 1 together with the recording command, and the control unit 80 acquires the image data transmitted from the PC.

[0039] In this embodiment, the image data acquired in S101 is data of an image P1 formed by arranging a plurality of pixels E in the X and Y directions that intersect with each other, as shown in FIG. 8(a), and includes data on these plurality of pixels E. Here, the X direction corresponds to the scanning direction when an image is recorded on the recording paper S based on the image data. The Y direction corresponds to the transport direction when an image is recorded on the recording paper S based on the image data. Furthermore, the data for each pixel E is data that includes information on whether the pixel is no ink droplet, a small droplet, a medium droplet, or a large droplet. In this embodiment, the Y direction corresponds to the "third direction," and the X direction corresponds to the "fourth direction."

[0040] Next, the control unit 80 executes a pixel data allocation process (S102). In the pixel data allocation process, the control unit 80 allocates data of four pixels E that are aligned consecutively in the Y direction among the multiple pixels E that form the image P1 indicated by the acquired image data to the four nozzle arrays 9A to 9D, respectively.

[0041] 8(a) and 8(b), of the multiple pixels E that make up image P1, data for every fourth pixel E, indicated by "A" in the figures, 1st, 5th, 9th, etc., counting from the top of Figure 8(a) in the Y direction, is assigned to nozzle row 9A. At this time, data for multiple pixels E that are at the same position in the Y direction are assigned to the same nozzle 10 in nozzle row 9A.

[0042] 8(a) and 8(c), of the multiple pixels E that make up image P1, data for every fourth pixel E, 2nd, 6th, 10th, etc., counting from the top of FIG. 8(a) in the Y direction, as indicated by "B" in the figures, is assigned to nozzle row 9B. At this time, data for multiple pixels E that are at the same position in the Y direction are assigned to the same nozzle 10 of nozzle row 9B.

[0043] 8(a) and 8(d), of the multiple pixels E that make up image P1, data for every fourth pixel E, 3rd, 7th, 11th, etc., counting from the top of FIG. 8(a) in the Y direction, as indicated by "C" in the figures, is assigned to nozzle row 9C. At this time, data for multiple pixels E at the same position in the Y direction is assigned to the same nozzle 10 of nozzle row 9C.

[0044] 8(a) and 8(e), of the multiple pixels E that make up image P1, data for every fourth pixel E, indicated by "D" in the figures, 4th, 8th, 12th, etc., counting from the top of FIG. 8(a) in the Y direction, is assigned to nozzle array 9D. At this time, data for multiple pixels E that are at the same position in the Y direction are assigned to the same nozzle 10 of nozzle array 9D.

[0045] Returning to FIG. 7, the control unit 80 then determines whether or not there is an abnormal nozzle among the multiple nozzles 10 of the inkjet head 4, based on the nozzle information stored in the memory 84 (S103). If there is no abnormal nozzle (S103: NO), the control unit 80 executes a recording process (S105). In the recording process, the control unit 80 causes the ejection scan and the transport operation to be repeated as described above, thereby recording an image on the recording paper S. In this embodiment, the process for performing the ejection scan in the recording process corresponds to the "ejection process."

[0046] At this time, in each discharge scan, ink is discharged from each nozzle 10 based on the data of pixel E assigned in S102. Also, as described above, in each discharge scan, ink is discharged from the multiple nozzles 10 constituting the nozzle rows 9A to 9D at timings when the nozzles are positioned at the same position in the scanning direction or reverse scanning direction.

[0047] By recording an image on the recording paper S in this manner, if there are no abnormal nozzles, as shown in FIG. 11(a), the image P2a recorded on the recording paper S will be four overlapping dots F formed by ink droplets ejected from four nozzles 10 of four nozzle arrays 9A-9D that are positioned at the same position in the transport direction, in multiple landing areas R1 on the recording paper S, which are arranged at intervals W in the scanning direction and at intervals of length L in the transport direction. Each dot F is formed on the recording paper S by ink droplets ejected based on the data of one pixel E. In FIG. 11(a), the dot F formed based on the pixel E assigned to nozzle 9A is indicated by "A," the dot F formed based on the pixel E assigned to nozzle 9B is indicated by "B," the dot F formed based on the pixel E assigned to nozzle 9C is indicated by "C," and the dot F formed based on the pixel E assigned to nozzle 9D is indicated by "D." 11(a), for ease of viewing, the four dots F landing in one landing area R1 are shown as not overlapping, but the positions of these four dots F may be approximately the same or only slightly offset, and they may overlap to a large extent. Also, in FIG. 11(a), a gap of length W is provided between two adjacent landing areas R1, but this gap length W is determined based on the recording resolution in the scanning direction. Also, in FIG. 11(a), a gap of length L is provided between two adjacent landing areas R1, but this gap length L is determined based on the recording resolution in the transport direction. However, this is not a limitation, and the lengths W and L may be determined appropriately depending on the recording resolution, and may be the same length or different from the length L.

[0048] 7, if there is an abnormal nozzle (S103: YES), the control unit 80 executes the discharge amount correction process (S104). In the discharge amount correction process of S104, the control unit 80 performs the process shown in the flowchart of FIG.

[0049] More specifically, in the discharge amount correction process, the control unit 80 sets one of the abnormal nozzles as the target nozzle (S201). Next, the control unit 80 sets one pixel E, of the multiple pixels E assigned to the target nozzle, whose data indicates that the ink droplet size is small, medium, or large, as the target pixel Es (S202).

[0050] Next, the control unit 80 sets the value of variable Z to 1 (S203). Here, in this embodiment, as shown in FIG. 10(a), priorities 1 to 3 are set for the remaining three nozzle arrays depending on which nozzle array the target nozzle is composed of, and this information is stored in memory 84. Priority 1 is the highest priority and priority 3 is the lowest priority. The value of variable Z corresponds to the priority. The closer a nozzle array to the nozzle array that composes the target nozzle is, the higher the priority is set. Also, in this embodiment, if there are adjacent nozzle arrays on both the left and right sides of the nozzle array that composes the target nozzle, the priority of the nozzle array on the left is set higher. However, conversely, if there are adjacent nozzle arrays on both the left and right sides of the nozzle array that composes the target nozzle, the priority of the nozzle array on the right may also be set higher.

[0051] Next, the control unit 80 determines whether any of the nozzles 10 constituting the nozzle row with priority Z and located in the same position in the transport direction as the target nozzle is an abnormal nozzle (S204). Note that, hereinafter, any of the nozzles 10 constituting the nozzle row with priority Z and located in the same position in the transport direction as the target nozzle may be referred to as the "nozzle 10 with priority Z." If the nozzle 10 with priority Z is an abnormal nozzle (S204: YES), the process proceeds to S207. If the nozzle 10 with priority Z is a normal nozzle (S204: NO), the control unit 80 determines whether the size of the ink droplet indicated by the data of pixel E, which is assigned to the nozzle 10 with priority Z and is intended to form a dot F in the same landing region R1 as the target pixel Es, is an extra-large droplet (S205). Note that, hereinafter, any of the pixels E assigned to the nozzle 10 with priority Z and is intended to form a dot F in the same landing region R1 as the target pixel Es may be referred to as the "corresponding pixel Ez for the nozzle 10 with priority Z."

[0052] Hereinafter, the four nozzles 10 to which four pixels E are assigned for forming four dots F within one landing area R1 will be referred to as the "four nozzles 10 corresponding to landing area R1." If two or more of the four nozzles 10 corresponding to a certain landing area R1 are abnormal nozzles, in S205, it may be determined that the size of the ink droplet indicated by the data for corresponding pixel Ez for the nozzle 10 with priority Z is an extra-large droplet.

[0053] To explain in more detail, for example, if two or more of the four nozzles 10 corresponding to a certain landing area R1 are abnormal nozzles, one of the four nozzles 10 corresponding to the landing area R1 is selected as the target nozzle, and the size of the ink droplet indicated by the data for pixel E for forming a dot F in the same landing area R1 as the target pixel Es of one of the normal nozzles is increased to an extra-large droplet by the processing of S206 described below. In this case, when another abnormal nozzle of the four nozzles 10 corresponding to the landing area R1 is subsequently selected as the target nozzle, the size of the ink droplet indicated by the data for corresponding pixel Ez for the nozzle 10 with priority Z is determined to be an extra-large droplet in S205.

[0054] If the size of the ink droplet indicated by the data of the corresponding pixel Ez for the nozzle 10 with priority Z is an extra-large droplet (S205: YES), the process proceeds to S207. If the size of the ink droplet indicated by the data of the corresponding pixel Ez for the nozzle 10 with priority Z is not an extra-large droplet (S205: NO), the control unit 80 increases the size of the ink droplet indicated by the data of the corresponding pixel Ez for the nozzle 10 with priority Z (S206). In other words, the control unit 80 increases the amount of ink ejected to form the dot F based on the corresponding pixel Ez for the nozzle 10 with priority Z compared to when the target nozzle is a normal nozzle. Then, after the process of S206, the process proceeds to S209.

[0055] In S206, as shown in FIG. 10(b), when the ink droplet size indicated by the data for the target pixel Es is small, medium, or large, the control unit 80 increases the ink droplet size indicated by the data for the corresponding pixel Ez for the nozzle 10 with priority Z by one, two, or three levels, respectively. FIG. 10(b) shows the relationship between the ink droplet size indicated by the data for the corresponding pixel Ez before resizing, the ink droplet size indicated by the data for the target pixel Es, and the ink droplet size indicated by the data for the corresponding pixel Ez after resizing. Also, in FIG. 10(b), increasing the ink droplet size by one to three levels is indicated as "+1" to "+3," respectively. Also, "none," "small," "medium," "large," and "extra large" in FIG. 10(b) represent no ink droplet, small droplet, medium droplet, large droplet, and extra large droplet, respectively.

[0056] Increasing the ink droplet size by one level means changing small droplets to medium droplets, changing medium droplets to large droplets, and changing large droplets to extra-large droplets. Increasing the ink droplet size by two levels means changing small droplets to large droplets and changing medium droplets to extra-large droplets. Increasing the ink droplet size by three levels means changing small droplets to extra-large droplets.

[0057] In this embodiment, the ink volumes of medium, large, and extra-large droplets are set to approximately two, three, and four times the ink volume of small droplets, respectively, and the size of the ink droplets is set as shown in Fig. 10(b). As a result, the total amount of ink ejected from nozzles 10 that are positioned in the same transport direction as the target nozzles toward the same landing area R1 as the target pixel Es is close to the total amount of ink ejected from the four nozzles 10 that correspond to the landing area R1 when the target nozzles are normal nozzles, i.e., it is an amount within a specific range that includes this total amount.

[0058] However, the relationship between the ink volumes of small, medium, large, and extra-large droplets may be different from that described above. In this case, by setting how large the ink droplets should be in accordance with the relationship between the ink volumes of small, medium, large, and extra-large droplets, the total amount of ink ejected from nozzles 10 that are positioned in the same transport direction as the target nozzles toward the same landing area R1 as the target pixel Es should be within a specific range that includes the total amount of ink ejected from the four nozzles 10 that correspond to the landing area R1 when the target nozzles are normal nozzles.

[0059] Furthermore, in this embodiment, the nozzle 10 cannot eject ink droplets with a larger ink volume than extra-large droplets. Therefore, if the ink droplet size indicated by the data for the corresponding pixel Ez is a medium droplet, the ink droplet size can only be increased by one or two levels. Also, if the ink droplet size indicated by the data for the corresponding pixel Ez is a large droplet, the ink droplet size can only be increased by one level.

[0060] Therefore, in this embodiment, if the data for corresponding pixel Ez indicates a medium ink droplet size and the data for target pixel Es indicates a large ink droplet size, the size of the ink droplet indicated by the data for corresponding pixel Ez is increased by two levels to form an extra-large droplet, unlike the method described above. Also, if the data for corresponding pixel Ez indicates a large ink droplet size and the data for target pixel Es indicates a medium or large ink droplet size, the size of the ink droplet indicated by the data for corresponding pixel Ez is increased by one level to form an extra-large droplet, unlike the method described above.

[0061] In S207, the control unit 80 determines whether the value of variable Z is 3. If the value of variable Z is not 3, that is, if the value of variable Z is 1 or 2 (S207: NO), the control unit 80 increments the value of variable Z by 1 (S208), and the process returns to S204. If the value of variable Z is 3 (S207: YES), the process proceeds to S209.

[0062] In S209, the control unit 80 determines whether or not there is a pixel E among the pixels E assigned to the target nozzle, the size of the ink droplet indicated by the pixel E data being either a small droplet, a medium droplet, or a large droplet, and that has not yet been set as a target pixel Es. If there is a corresponding pixel E among the pixels E assigned to the target nozzle (S209: YES), the process returns to S202. In S202 after returning from S209, one pixel E among the multiple pixels E assigned to the target nozzle, the size of the ink droplet indicated by the pixel E data being either a small droplet, a medium droplet, or a large droplet, and that has not yet been set as a target pixel Es, is set as the target pixel Es.

[0063] If there is no corresponding pixel E among the pixels E assigned to the target nozzles (S209: NO), the control unit 80 determines whether there is an abnormal nozzle that has not yet been set as a target nozzle (S210). If there is an abnormal nozzle that has not yet been set as a target nozzle (S210: YES), the process returns to S201. After returning from S210, in S201, one abnormal nozzle that has not yet been set as a target nozzle is set as the target nozzle. If there is no abnormal nozzle that has not yet been set as a target nozzle (S210: NO), the control unit 80 returns to the flowchart of FIG. 7 and executes the recording process (S106). In this recording process, the control unit 80 controls the inkjet head 4 to prevent the abnormal nozzle from ejecting ink.

[0064] In this embodiment, each abnormal nozzle corresponds to a "first nozzle," and the nozzle row including the first nozzle among the four nozzle rows 9A to 9D corresponds to the "first nozzle row." Furthermore, the three nozzle rows other than the first nozzle among the four nozzle rows 9A to 9D correspond to the "second to fourth nozzle rows," that is, three "Mth nozzle rows" where M is an integer between 2 and 4, and M is an integer between 2 and 4. Furthermore, the nozzles 10 in the second to fourth nozzle rows that are located in the same position in the transport direction as the abnormal nozzle in each of the second to fourth nozzle rows correspond to the "second to fourth nozzles," that is, the "Mth nozzle" of each of the Mth nozzle rows. Note that this embodiment is an example in which the number N of nozzle rows is 4.

[0065] <Effects> In this embodiment, as described above, ink droplets ejected from four nozzles 10 in the nozzle rows 9A to 9D that are positioned at the same location in the transport direction land on the same landing area R1 on the recording paper S, and these ink droplets form four overlapping dots F in the landing area R1. At this time, the positions of these four dots F are slightly shifted. Therefore, in this case, a larger proportion of the landing area R1 is covered with the landed ink than when the same amount of ink as the total amount of ink ejected from these four nozzles 10 is ejected onto the landing area R1 from only one nozzle 10. This improves the image quality of the image recorded on the recording paper S.

[0066] On the other hand, if there is an abnormal nozzle and the printing process is performed without performing the ejection volume correction process, as opposed to the present embodiment, the number of dots F formed in the landing area R1 corresponding to the abnormal nozzle in the printed image P2b will be three or less, as shown in Figure 11(b). As a result, the proportion of the landing area R1 covered by the landed ink will be small, leading to a deterioration in image quality. Figure 11(b) shows a case where one of the multiple nozzles 10 constituting the nozzle row 9B is an abnormal nozzle.

[0067] In contrast, in this embodiment, if there is an abnormal nozzle, the ejection amount correction process is performed before the recording process is performed. As a result, as shown in FIG. 11(c), in the recorded image P2c, the number of dots F formed in the landing area R1 corresponding to the abnormal nozzle is three or less, but the size of at least one of these three or less dots F is larger than when the ejection amount correction process is not performed. As a result, even if there is an abnormal nozzle, the proportion of the landing area R1 corresponding to the abnormal nozzle that is covered by the landed ink is prevented from decreasing, thereby preventing a deterioration in image quality. FIG. 11(c) shows a case where one of the multiple nozzles 10 constituting nozzle row 9B is an abnormal nozzle, and the ink ejection amount of the nozzle 10 constituting nozzle row 9C that is located at the same position in the transport direction as the abnormal nozzle is increased.

[0068] Furthermore, in this embodiment, as described above, the total amount of ink ejected from the nozzles 10 that are positioned in the same transport direction as the target nozzles toward the same landing area R1 as the target pixel Es is set to be an amount within a specific range that includes the total amount of ink ejected toward the landing area R1 from the four nozzles 10 that correspond to the landing area R1 when the target nozzles are normal nozzles. This prevents the difference in the proportion of the landing area R1 that is covered by the landed ink between when there is no abnormal nozzle and when there is an abnormal nozzle from becoming too large, thereby preventing a decrease in the quality of the printed image.

[0069] Furthermore, in this embodiment, four nozzle rows 9A to 9D, each formed by lining up a plurality of nozzles 10 in the transport direction, are aligned in the scanning direction, and the nozzles 10 are positioned in the same transport direction in the four nozzle rows 9A to 9D. As a result, during an ejection scan, when ink is ejected from the plurality of nozzles 10 constituting the nozzle rows 9A to 9D at timings when the nozzles 10 are positioned in the same scanning direction for each of the nozzle rows 9A to 9D, the ink ejected from the four nozzles 10 positioned in the same transport direction in the four nozzle rows 9A to 9D can be made to overlap in the same landing region R1 on the recording paper S.

[0070] <Modification> Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims.

[0071] In the above-described embodiment, the total amount of ink ejected from nozzles 10 that are positioned in the same direction as the target nozzle toward the same landing area R1 as the target pixel Es is set to be an amount within a specific range that includes the total amount of ink ejected toward the landing area R1 from the four nozzles 10 that correspond to the landing area R1 when the target nozzle is a normal nozzle, but this is not limited to this.

[0072] For example, the total amount of ink ejected from nozzles 10 located in the same position as the target nozzle in the transport direction toward the same landing region R1 as the target pixel Es may be set to be greater than or less than the amount within the specific range. Alternatively, for example, the size of the ink droplet indicated by the data for the corresponding pixel Ez may be increased regardless of the size of the ink droplet indicated by the data for the target pixel Es. In other words, the amount of ink ejected from nozzles 10 located in the same position as the target nozzle in the transport direction toward the same landing region R1 as the target pixel Es may be increased regardless of the amount of ink ejected from the target nozzle.

[0073] Furthermore, in the above-described embodiment, when one of the nozzles 10 in a certain nozzle row is an abnormal nozzle, only the amount of ink ejected from one nozzle 10 that is located at the same position in the transport direction as the abnormal nozzle in another nozzle row is increased, but this is not limited to this.

[0074] In the ejection amount correction process of Modification 1, the control unit 80 performs the process shown in the flowchart of Fig. 12. To explain in detail, in the ejection amount correction process of Modification 1, the control unit 80 sets the target nozzle (S301) and sets the target pixel Es (S302), similar to S201 and S202 in the above-described embodiment.

[0075] Next, the control unit 80 determines whether there is a normal nozzle among the three nozzles 10 that are in the same position in the transport direction as the target nozzle (S303). If there is no normal nozzle among the three nozzles 10 that are in the same position in the transport direction as the target nozzle (S303: NO), the control unit 80 performs the process of S308, which is the same as S210 in the above embodiment.

[0076] If there is a normal nozzle among the three nozzles 10 that are positioned in the same transport direction as the target nozzle (S303: YES), the control unit 80 determines whether there is only one normal nozzle among the three nozzles 10 that are positioned in the same transport direction as the target nozzle (S304). If there is only one normal nozzle among the three nozzles 10 that are positioned in the same transport direction as the target nozzle (S304: YES), the control unit 80 increases the size of the ink droplet indicated by the data for pixel E that is formed in the same landing region R1 as the target pixel Es, among the pixels E assigned to this one normal nozzle (S305). In S305, the extent to which the size of the ink droplet indicated by the data for corresponding pixel Ez is increased is, for example, the same as in S206 in the above-mentioned embodiment.

[0077] If there are multiple normal nozzles among the three nozzles 10 that are positioned in the same transport direction as the target nozzle (S304: NO), the control unit 80 increases the size of the ink droplets in the data for at least one of the multiple pixels E assigned to these multiple normal nozzles so that the sizes of the ink droplets indicated by the data for the multiple pixels E for forming multiple dots F in the same landing region R1 as the target pixel Es are uniform (S306). Ensuring that the sizes of the ink droplets forming the multiple dots F formed in the same landing region R1 as the target pixel Es are uniform means that the sizes of the ink droplets indicated by the data for the multiple pixels E corresponding to these multiple dots F are uniform, or, if there is a difference in the sizes of the ink droplets indicated by the data for these multiple pixels E, that difference is minimized.

[0078] After increasing the size of the ink droplets in S305 or S306, the control unit 80 performs the processes of S307 and S308, which are the same as S209 and S210 in the above embodiment.

[0079] In Modification 1, when there are multiple normal nozzles that are located at the same position in the transport direction as the target nozzle, the amount of ink droplet liquid ejected from at least one of these multiple normal nozzles is increased compared to when the target nozzle is a normal nozzle. This prevents a decrease in the proportion of the impact area R1 that is covered by the impacted ink, even for an abnormal nozzle, and prevents a decrease in the quality of the printed image.

[0080] Furthermore, in Modification 1, when there are multiple normal nozzles that are positioned in the same direction as the target nozzle, the amount of liquid ejected from at least one of these multiple normal nozzles is increased compared to when the target nozzle is a normal nozzle, so that the amount of ink ejected from these multiple normal nozzles is equalized. This makes it possible to prevent uneven coverage of the area of ​​impact region R1 that is covered by the landed liquid, which would be caused by increasing the amount of ink ejected from the normal nozzles.

[0081] Furthermore, in variant 1, if there are multiple normal nozzles that are positioned in the same direction as the target nozzle, the amount of ink ejected from at least one of these multiple normal nozzles may be increased so that there is a fairly large difference in the amount of ink ejected from these multiple normal nozzles.

[0082] In the second modification, in the discharge amount correction process, the control unit 80 performs the process shown in the flowchart of Fig. 13. More specifically, in the discharge amount correction process of the second modification, the control unit 80 executes the processes of S401 to S404, which are the same as S201 to S204 in the embodiment described above. If it is determined in S404 that the nozzle 10 with priority Z is an abnormal nozzle (S404: YES), the process proceeds to S408. If it is determined in S404 that the nozzle 10 with priority Z is a normal nozzle (S404: NO), the control unit 80 determines whether the size of the ink droplet indicated by the data of the corresponding pixel Ez for the nozzle 10 with priority Z is an extra-large droplet (S405), as in S205 in the embodiment described above.

[0083] If the size of the ink droplet indicated by the data of the corresponding pixel Ez for the nozzle 10 with priority Z is an extra-large droplet (S405: YES), the process proceeds to S408. If the size of the ink droplet indicated by the data of the corresponding pixel Ez for the nozzle 10 with priority Z is not an extra-large droplet (S405: NO), the control unit 80 increases the size of the ink droplet indicated by the data of the corresponding pixel Ez for the nozzle 10 with priority Z (S406). In S406, unlike S206 in the above embodiment, the size of the ink droplet is always increased by one level.

[0084] Next, the control unit 80 determines whether the total increase amount Is is equal to or greater than a predetermined amount J (S407). The total increase amount Is is the sum of the increase amounts of ink ejected from the nozzles 10 that have increased their ejection amounts among the nozzles 10 that eject ink into the same landing region R1 as the target pixel Es. The total increase amount Is is calculated, for example, based on the number of steps by which the ink droplet size indicated by the data for each corresponding pixel Ez has been increased. The predetermined amount J is an amount within a specified range that includes the amount of ink ejected from the target nozzle when the target nozzle is a normal nozzle. The predetermined amount J may be the exact amount of ink ejected from the target nozzle when the target nozzle is a normal nozzle, or it may be an amount greater than or less than this amount. The predetermined amount J is calculated, for example, based on the size of the ink droplet indicated by the data for the target pixel Es.

[0085] If the total increase amount Is is less than the predetermined amount J (S407: NO), the process proceeds to S408. If the total increase amount Is is equal to or greater than the predetermined amount J (S407: YES), the same processes as S209 and S210 in the above embodiment are executed in S411 and S412.

[0086] In S408, it is determined whether the value of variable Z is 3. If the value of variable Z is not 3 (S408: NO), the control unit 80 increments the value of variable Z by 1 (S409), and the process returns to S404. If the value of variable Z is 3 (S408: YES), the control unit 80 determines whether there is a pixel E that can further increase the size of the ink droplet indicated by the data of pixel E, among the pixels E for forming dot F in the same landing region R1 as the target pixel Es (S410). If there is a corresponding pixel E (S410: YES), the process returns to S403. If there is no corresponding pixel E (S410: NO), the control unit 80 executes the processes of S411 and S412.

[0087] In Modification 2, when there are multiple normal nozzles that are located in the same position in the transport direction as the target nozzle, the amount of ink droplet liquid ejected from at least one of these multiple normal nozzles is increased compared to when the target nozzle is a normal nozzle. This prevents a decrease in the proportion of the impact area R1 that is covered by the impacted ink, even if there is an abnormal nozzle, and prevents a decrease in the quality of the printed image.

[0088] In addition, in Modification 2, when there are multiple normal nozzles located at the same position in the transport direction as the target nozzle, the ink ejection volume for one normal nozzle to form the corresponding pixel Ez is increased compared to when the target nozzle is a normal nozzle. Furthermore, when the increase in the ink ejection volume from one normal nozzle is less than the amount within a specified range including the ink ejection volume from the target nozzle when the target nozzle is a normal nozzle, the ink ejection volume for each normal nozzle to form the corresponding pixel Ez is increased compared to when the target nozzle is a normal nozzle, until the total increase volume Is reaches a predetermined volume J or the ink ejection volumes for all normal nozzles have been increased. Furthermore, when the total increase volume of the ink ejection volumes for all normal nozzles is less than the predetermined volume J and the ink ejection volume from the one normal nozzle after the increase is less than the maximum ejection volume that can be ejected from the one normal nozzle, the ink ejection volume for forming the corresponding pixel Ez for the one normal nozzle is further increased. As a result, even if there is an abnormal nozzle, it is possible to prevent the proportion of the landing area R1 that is covered by the landed ink from decreasing, and to prevent degradation in the quality of the printed image.

[0089] Furthermore, in Modification 2, the amount of ink ejected from high-priority normal nozzles, i.e., normal nozzles that are close to the target nozzle and have a pixel E assigned to them that is close to the target pixel Es in the image represented by the image data, is increased first. This increases the size of pixel E formed by ink ejected from nozzles 10 close to the target nozzles and that are close to the target pixel Es in the Y direction in the image P1 represented by the image data when the target pixel Es is not formed. As a result, it is possible to enhance the effect of suppressing degradation in the quality of the image recorded on the recording paper S, which would be caused by increasing the amount of ink ejected from normal nozzles.

[0090] In Modification 2, by performing the ejection amount correction process as described above, among the nozzles 10 that are positioned in the same transport direction as the target nozzle, the ink ejection amount from the nozzles 10 that constitute the nozzle row adjacent to the nozzle row that includes the target nozzle is increased with priority over the ink ejection amount from the nozzles 10 that constitute the other nozzle rows. Note that in Modification 2, the condition that "the nozzle is a nozzle 10 that constitutes a nozzle row adjacent to the nozzle row that includes the target nozzle" corresponds to the "specific condition."

[0091] Furthermore, in Modification 2, as in the embodiment described above, data for four pixels E that are consecutively arranged in the Y direction in the image data are assigned in order to four nozzle arrays 9A to 9D that are adjacent in the scanning direction. Therefore, in Modification 2, by performing the ejection amount correction process as described above, among the nozzles 10 that are positioned in the same position in the transport direction as the target nozzle, the ink ejection amount from the nozzles 10 to which the pixel E adjacent to the target pixel Es in the Y direction is assigned is increased with priority over the ink ejection amount from the nozzles 10 to which a pixel E that is not adjacent to the target pixel Es in the Y direction is assigned. In other words, in Modification 2, the condition that "the nozzle 10 is assigned to a pixel E adjacent to the target pixel Es in the Y direction" can also be said to be the "specific condition."

[0092] Furthermore, in Modification 2, when it is determined in S408 that the value of variable Z is 3, the control unit 80 may execute the processes of S411 and S412. In this case, for example, the size of the ink droplet indicated by the data of a certain corresponding pixel Ez may be increased, if possible, so that the total increase amount Is reaches a predetermined amount J. On the other hand, even if the size of the ink droplet indicated by the data of a certain corresponding pixel Ez is increased to the maximum possible size to make it an extra-large droplet, if the total increase amount Is does not reach the predetermined amount J, the size of the ink droplet indicated by the data of the certain corresponding pixel Ez may be set to an extra-large droplet, and the size of the ink droplet indicated by the data of another corresponding pixel Ez may be increased.

[0093] Furthermore, in the above-described embodiment, when there are adjacent nozzle rows on both the left and right sides of a nozzle row containing an abnormal nozzle, the priority of one of these nozzle rows is uniformly set to be higher than the priority of the other nozzle row, but this is not limited to this.

[0094] In Modification 3, as shown in FIG. 14(a), when the target nozzle is a nozzle 10 constituting nozzle row 9B, the nozzle rows 9A and 9C adjacent to the left and right of nozzle row 9B are set to priority 1, and nozzle row 9D is set to priority 2. Furthermore, when the abnormal nozzle is a nozzle 10 constituting nozzle row 9C, the nozzle rows 9B and 9D adjacent to the left and right of nozzle row 9C are set to priority 1, and nozzle row 9A is set to priority 2. In these cases, no nozzle row is set to priority 3. Furthermore, when the abnormal nozzle is a nozzle 10 constituting nozzle row 9A, the priorities 1 to 3 are set for nozzle rows 9B to 9D, and when the abnormal nozzle is a nozzle 10 constituting nozzle row 9D, the priorities 1 to 3 are set for nozzle rows 9A to 9C, as in the above-described embodiment.

[0095] In the discharge amount correction process of the third modification, the control unit 80 performs the processes shown in the flowcharts of Figures 14(b), 15, 16(a) to (c), and 17(a). More specifically, in the discharge amount correction process of the third modification, as shown in Figure 14(b), the control unit 80 sets the target nozzle (S501) and sets the target pixel Es (S502), similar to S201 and S202 of the above-described embodiment.

[0096] Next, the control unit 80 determines whether the target nozzle is a nozzle 10 that constitutes either the nozzle row 9B or 9C (S503). If the target nozzle is not a nozzle 10 that constitutes either the nozzle row 9B or 9C, i.e., if the target nozzle is a nozzle 10 that constitutes either the nozzle row 9A or 9D (S503: NO), as shown in FIG. 15, the control unit 80 executes the processes of S601 to S608, which are the same as S203 to S210 in the above-described embodiment. However, in Modification 3, if it is determined in S607 that among the pixels E assigned to the target nozzle, there is a pixel E whose ink droplet size indicated by the data of pixel E is small, medium, or large, and which has not yet been set as the target pixel Es (S607: YES), the process returns to S502 in FIG. 14(b). Also, if it is determined in S608 that there is an abnormal nozzle that has not yet been set as the target nozzle (S608: YES), the process returns to S501 in FIG. 14(b).

[0097] Returning to FIG. 14(b), if the target nozzle is a nozzle 10 that constitutes either nozzle row 9B or 9C (S503: NO), the control unit 80 determines whether each of the two nozzles 10 with priority 1 is an abnormal nozzle (S504).

[0098] If both of the two nozzles 10 with priority 1 are abnormal nozzles (S504: both abnormal), as shown in Figure 16(a), the control unit 80 determines whether the nozzle 10 with priority 2 is an abnormal nozzle (S701). If the nozzle 10 with priority 2 is an abnormal nozzle (S701: YES), the process proceeds to S607 in Figure 15.

[0099] If the nozzle 10 with priority 2 is a normal nozzle (S701: NO), the control unit 80 determines whether the size of the ink droplet indicated by the data of the pixel Ez corresponding to the nozzle 10 with priority 2 is an extra-large droplet (S702). If the size of the ink droplet indicated by the data of the pixel Ez corresponding to the nozzle 10 with priority 2 is an extra-large droplet (S702: YES), the process proceeds to S607 in FIG. 14. If the size of the ink droplet indicated by the data of the pixel Ez corresponding to the nozzle 10 with priority 2 is not an extra-large droplet (S702: NO), the control unit 80 increases the size of the ink droplet indicated by the data of the pixel Ez corresponding to the nozzle 10 with priority 2 (S703), and the process proceeds to S607 in FIG. 15. In S703, the extent to which the size of the ink droplet indicated by the data of the pixel Ez corresponding to the nozzle 10 with priority 2 is increased is, for example, the same as S206 in the above-described embodiment.

[0100] Returning to FIG. 14(b), if only the left nozzle 10 of the two nozzles 10 with priority 1 is an abnormal nozzle (S504: only the left nozzle is abnormal), as shown in FIG. 16(b), the control unit 80 determines whether the size of the ink droplet indicated by the data of the corresponding pixel Ez for the right nozzle 10 of the two nozzles 10 with priority 1 is extra-large (S801). If the size of the ink droplet indicated by the data of the corresponding pixel Ez for the right nozzle 10 of the two nozzles with priority 1 is extra-large (S801: YES), the process proceeds to S701 in FIG. 16(a). If the size of the ink droplet indicated by the data of the corresponding pixel Ez for the right nozzle 10 of the two nozzles with priority 1 is not extra-large (S801: NO), the control unit 80 increases the size of the ink droplet indicated by the data of the corresponding pixel Ez for the right nozzle 10 of the two nozzles 10 with priority 1 (S802), and the process proceeds to S607 in FIG. 15. In S802, the extent to which the size of the ink droplet indicated by the data of the corresponding pixel Ez for the right-hand nozzle 10 of the two nozzles 10 with priority 1 is increased is the same as in S206 in the above embodiment, for example.

[0101] Returning to FIG. 14(b), if only the right nozzle 10 of the two nozzles 10 with priority 1 is an abnormal nozzle (S504: only the right nozzle is abnormal), as shown in FIG. 16(c), the control unit 80 determines whether the size of the ink droplet indicated by the data of the corresponding pixel Ez for the left nozzle 10 of the two nozzles with priority 1 is extra-large (S901). If the size of the ink droplet indicated by the data of the corresponding pixel Ez for the left nozzle 10 of the two nozzles with priority 1 is extra-large (S901: YES), the process proceeds to S701 in FIG. 16(a). If the size of the ink droplet indicated by the data of the corresponding pixel Ez for the left nozzle 10 of the two nozzles with priority 1 is not extra-large (S901: NO), the control unit 80 increases the size of the ink droplet indicated by the data of the corresponding pixel Ez for the left nozzle 10 of the two nozzles with priority 1 (S902), and the process proceeds to S607 in FIG. 15. In S902, the extent to which the size of the ink droplet indicated by the data of the corresponding pixel Ez for the left nozzle 10 of the two nozzles 10 with priority 1 is increased is the same as in S206 in the above embodiment, for example.

[0102] Returning to Fig. 14(b), if both of the two nozzles 10 with priority 1 are normal nozzles (S504: both normal), as shown in Fig. 17(a), the control unit 80 determines whether the size of the ink droplet indicated by the data of the corresponding pixel Ez for each of the two nozzles 10 with priority 1 is extra-large (S1001). If the size of the ink droplet indicated by the data of the corresponding pixel Ez for both of the two nozzles 10 with priority 1 is extra-large (S1001: both are extra-large), the process proceeds to S701 in Fig. 16(a).

[0103] If the size of the ink droplet indicated by the data of the corresponding pixel Ez for only the left nozzle 10 of the two nozzles 10 with priority 1 is an extra-large droplet (S1001: extra-large droplet only on the left), the control unit 80 increases the size of the ink droplet indicated by the data of the corresponding pixel Ez for the right nozzle 10 of the two nozzles 10 with priority 1 (S1002), as in S802 of Figure 16(b), and processing proceeds to S607 of Figure 15.

[0104] If the size of the ink droplet indicated by the data of the corresponding pixel Ez for only the right-hand nozzle 10 of the two nozzles 10 with priority 1 is extra-large (S1001: extra-large droplets only on the right), the control unit 80 increases the size of the ink droplet indicated by the data of the corresponding pixel Ez for the left-hand nozzle 10 of the two nozzles 10 with priority 1 (S1003), as in S902 of Figure 16(c), and processing proceeds to S607 of Figure 15.

[0105] If the size of the ink droplet indicated by the data of the corresponding pixel Ez for both of the two nozzles 10 with priority 1 is not extra-large (S1001: both are not extra-large), the control unit 80 increases the size of the ink droplet indicated by the data of the corresponding pixel Ez for one or both of the two nozzles 10 with priority 1 based on the relationship between the ink droplet size before change of the corresponding pixel Ez for each of the two nozzles 10 with priority 1 and the ink droplet size indicated by the data of the target pixel Es (S1004), as shown in Figure 17(b), and processing proceeds to S607 in Figure 15.

[0106] Here, "none / none" in Figure 17(b) indicates the combination of ink droplet sizes before the change indicated by the data of the corresponding pixel Ez for the two nozzles 10 with priority 1. Also, "+0" in Figure 17(b) indicates that the ink droplet size will not be changed.

[0107] In S1004, if the ink droplet sizes before the change indicated by the corresponding pixel Ez data for the two nozzles 10 with priority 1 are the same, such as "none / none," "small / small," "medium / medium," and "large / large" in Fig. 17(b), the ink droplet sizes indicated by the corresponding pixel Ez data for the two nozzles 10 with priority 1 are increased by the same amount. Specifically, the ink droplet sizes indicated by the corresponding pixel Ez data for the two nozzles 10 with priority 1 are increased by the same amount, or the ink droplet sizes indicated by the corresponding pixel Ez data for the two nozzles 10 with priority 1 are increased by different amounts, but the difference is made to be one step.

[0108] Furthermore, in S1004, if there is a difference in the ink droplet sizes before the change indicated by the corresponding pixel Ez data for the two nozzles 10 with priority 1, such as "none / small," "none / medium," "none / large," "small / medium," "small / large," and "medium / large" in FIG. 17(b), the ink droplet size indicated by the corresponding pixel Ez data for the smaller ink droplet size before the change is increased preferentially over the ink droplet size indicated by the corresponding pixel Ez data for the larger ink droplet size before the change. In other words, the increase in the ejection volume for the nozzle 10 with the smaller ejection volume before the increase is increased preferentially. However, at this time, the relationship between the ink droplet sizes indicated by the corresponding pixel Ez data for the two nozzles 10 with priority 1 before and after the change is not reversed. Note that if there is a difference in the ink droplet sizes before the change indicated by the corresponding pixel Ez data for the two nozzles 10 with priority 1, the ink droplet sizes after the change indicated by the corresponding pixel Ez data for the two nozzles 10 with priority 1 may be the same.

[0109] In Modification 3, too, priority is given to increasing the amount of ink ejected from high-priority normal nozzles, that is, normal nozzles that are close to the target nozzle and to which a pixel E close to the target pixel Es in the image represented by the image data is assigned. As a result, when the target pixel Es is not formed, the size of pixel E formed by ink ejected from normal nozzles close to the target nozzle and that is close to the target pixel Es in the Y direction in the image P1 represented by the image data increases. As a result, it is possible to enhance the effect of suppressing degradation in the quality of the image recorded on the recording paper S, which would be caused by increasing the amount of ink ejected from normal nozzles.

[0110] Furthermore, in Modification 3, when the data for the corresponding pixel Ez for the two nozzles 10 with priority 1 indicate the same ink droplet size before the change, the sizes of the ink droplets indicated by the data for the corresponding pixel Ez for the two nozzles 10 with priority 1 are increased equally. This makes it possible to suppress fluctuations in the difference between the amount of ink ejected from one of the two nozzles 10 and the amount of ink ejected from the other nozzle 10, which would occur if the size of the ink droplets indicated by the data for the corresponding pixel Ez for the two nozzles 10 with priority 1 were increased.

[0111] Furthermore, in Modification 3, when there is a difference in the ink droplet sizes before the change indicated by the data for the corresponding pixel Ez for two nozzles 10 with priority 1, the ink droplet size indicated by the data for the corresponding pixel Ez with the smaller ink droplet size before the change is preferentially increased over the ink droplet size indicated by the data for the corresponding pixel Ez with the larger ink droplet size before the change. In other words, the increase in the ejection volume of the nozzle 10 with priority 1 that had the smaller ejection volume before the increase is preferentially increased. This makes it possible to prevent bias in the range of the impact region R1 covered by the landed ink, which would occur if the ink ejection volume from at least one of the two nozzles 10 with priority 1 were increased.

[0112] Furthermore, in variant example 3, when there is a difference in the size of the ink droplets before the change indicated by the data of the corresponding pixel Ez for the two nozzles 10 with priority 1, and the data of the corresponding pixel Ez with the smaller ink droplet size before the change is given priority to increasing the size of the ink droplets, the relationship in size of the ink droplets indicated by the data of the corresponding pixel Ez for the two nozzles 10 with priority 1 before and after the change in the size of the ink droplets may be reversed.

[0113] Furthermore, in variant example 3, in both cases where the size of the ink droplets indicated by the data of the corresponding pixel Ez for the two nozzles 10 with priority 1 is the same, and where there is a difference in the size of the ink droplets indicated by the data of the corresponding pixel Ez for the two nozzles 10 with priority 1, the size of the ink droplets indicated by the data of the corresponding pixel Ez for the two nozzles 10 with priority 1 may be increased equally.

[0114] Alternatively, in variant example 3, when increasing the size of the ink droplets indicated by at least one of the corresponding pixels Ez for two nozzles 10 with priority 1, the difference in size of the ink droplets indicated by these two corresponding pixels Ez may be made larger.

[0115] Alternatively, in variant example 3, if there is a difference in the size of the ink droplets indicated by the data of the corresponding pixel Ez for two nozzles 10 with priority 1, the size of the ink droplets indicated by the data of the corresponding pixel Ez with the larger ink droplet size before the change may be made larger in preference to the size of the ink droplets indicated by the data of the corresponding pixel Ez with the smaller ink droplet size before the change.

[0116] In the above example, the data of four pixels E that are consecutively arranged in the Y direction in the image data are respectively assigned to four nozzle arrays 9A to 9D that are adjacent in the scanning direction. Also, in the example where priority is set for the nozzle arrays, the nozzle array closer to the target nozzle has a higher priority. However, this is not limited to this.

[0117] For example, the priority of the nozzle rows may be set based on another criterion regarding the positional relationship between the target nozzle and each nozzle row. In this case, among the nozzles 10 that are located at the same position in the transport direction as the target nozzle, the ink ejection volume from the nozzles 10 that make up the nozzle row with priority 1 is increased preferentially over the ink ejection volume from the nozzles 10 that make up the other nozzle rows.

[0118] Alternatively, for example, four pixels E that are consecutively arranged in the Y direction in the image data may be assigned to the four nozzle arrays 9A to 9D in a different order. In this case, when the nozzle array closer to the target nozzle is assigned a higher priority, the size of the ink droplet indicated by the data of the corresponding pixel Ez that is farther from the target pixel Es in the image P1 indicated by the image data may be increased preferentially.

[0119] In this case, the priority may be set based on the positional relationship between the target pixel Es and the corresponding pixel Ez in the image P1, rather than the positional relationship between the target nozzle and each nozzle array, for example, by assigning a higher priority to a corresponding pixel Ez closer to the target pixel Es in the image data. In this case, the size of the ink droplet indicated by the pixel data may be increased preferentially for the corresponding pixel Ez for the nozzle array farther from the target nozzle.

[0120] In these examples, the condition that "it is a nozzle 10 that constitutes a nozzle row with priority 1" corresponds to the "specific condition." The specific condition may also be another condition that is set based on various factors, such as the positional relationship between the target nozzle and each nozzle row, and the positional relationship between the target pixel Es and the corresponding pixel Ez.

[0121] Furthermore, in the above example, the multiple nozzles 10 constituting the nozzle rows 9A to 9D are aligned in the transport direction, and the nozzles 10 of the nozzle rows 9A to 9D are positioned at the same position in the transport direction, but this is not limited to this.

[0122] In Modification 4, as shown in Fig. 18, the inkjet head 4 is tilted in plan view with respect to the posture in the above-described embodiment. As a result, the multiple nozzles 10 constituting the nozzle rows 9A to 9D are aligned in an arrangement direction that is tilted with respect to the transport direction, and the nozzles 10 are positioned in the same position in the arrangement direction of the nozzle rows 9A to 9D. Note that in Modification 2, the arrangement direction corresponds to the "second direction."

[0123] In addition, in Modification 4, in each of the nozzle rows 9A to 9D, the multiple nozzles 10 that make up the nozzle row are lined up at intervals of length L in the transport direction, and the positions of the nozzles 10 between adjacent nozzle rows are shifted by length L / 4 in the transport direction. As a result, in Modification 4, the multiple nozzles 10 that make up the four nozzle rows 9A to 9D of the inkjet head 4 are arranged at intervals of length L / 4 in the transport direction.

[0124] In Modification 4, when a recording command is received, the control unit 80 performs the processing shown in the flowcharts of Figures 7(a) and 9, as described in the above embodiment. However, in Modification 4, the image to be recorded differs from that in the above embodiment.

[0125] 19(a), in the case where there is no abnormal nozzle, the image P3a recorded on the recording paper S is formed by ink droplets ejected from four nozzles 10 of four nozzle rows 9A to 9D that are positioned at the same position in the transport direction, and four dots F are arranged at intervals of length L / 4 in the transport direction in a plurality of landing areas R2 that are arranged at intervals of length W in the scanning direction on the recording paper S and at intervals of length L in the transport direction. In other words, the resolution in the transport direction of the image recorded in the fourth modification is four times that of the image recorded in the above-described embodiment.

[0126] On the other hand, if there is an abnormal nozzle and the recording process is performed without performing the ejection amount correction process, as opposed to Variation 4, then in the recorded image P3b, as shown in FIG. 19(b), the number of overlapping dots F in the landing area R2 corresponding to the abnormal nozzle will be three or less. As a result, the proportion of the landing area R2 covered by the landed ink will be small, leading to a deterioration in image quality. Specifically, in the recorded image P3b, an area where no ink has landed that extends across the entire length of the recording paper S in the scanning direction of the recording paper S will be easily noticeable as a so-called white streak, leading to a deterioration in image quality. FIG. 19(b) shows a case where one of the multiple nozzles 10 constituting the nozzle row 9B is an abnormal nozzle.

[0127] In contrast, in Modification 4, if an abnormal nozzle is present, the ejection volume correction process is performed before the recording process. As a result, as shown in FIG. 19(c), in the recorded image P3c, the number of dots F formed in the landing area R2 corresponding to the abnormal nozzle is three or less, but the size of at least one of these three or less dots F is larger than when the ejection volume correction process is not performed. As a result, even if an abnormal nozzle is present, the proportion of the landing area R2 corresponding to the abnormal nozzle that is covered by the ink is prevented from decreasing, thereby suppressing degradation of image quality. Specifically, the white stripes described above are less noticeable, thereby suppressing degradation of image quality. FIG. 19(c) illustrates a case where one of the multiple nozzles 10 constituting nozzle row 9B is abnormal, and the ink ejection volume of the nozzle 10 constituting nozzle row 9C that is located at the same position in the transport direction as the abnormal nozzle is increased.

[0128] In the above example, the control unit 80 provided in the printer 1 controls the printer 1 during recording, but the present invention is not limited to this.

[0129] As shown in FIG. 20 , an image recording system 100 according to Modification 5 includes a printer 101 and a control device 102. The printer 101 is similar to the printer 1 of the above-described embodiment. The control device 102 is a device provided external to the printer 1, connected to the printer 1 via a wired or wireless connection, and capable of communicating with the printer 1. Like the control unit 80 of the above-described embodiment, the control device 102 includes a CPU, ROM, RAM, memory, and the like, and controls the operation of each part of the printer 101 by sending signals to the printer 101. In Modification 5, the control device 102 also includes a storage unit 103 that stores the nozzle information described in the above-described embodiment. The storage unit 103 is formed, for example, by the memory of the control device 102. Alternatively, in Modification 5, the printer 101 may include a storage unit that stores the nozzle information. In the recording system 100 according to Modification 5, the control device 102 controls the operation of each part of the printer 101, causing the printer 101 to record an image on recording paper S, in the same manner as described above.

[0130] In the same manner as described in the above embodiment, in the fifth modification, ink ejected from four nozzles 10 of the four nozzle rows 9A to 9D that are positioned at the same position in the transport direction lands in the same landing area R1, thereby improving the quality of the image recorded on the recording paper S. Furthermore, even if there is an abnormal nozzle, the proportion of the landing area R1 corresponding to the abnormal nozzle that is covered by the ink that has landed therein is prevented from decreasing, thereby preventing a decrease in image quality.

[0131] Furthermore, in the above example, the ejection inspection unit 20 inspects whether a nozzle is normal or abnormal based on a signal corresponding to a change in voltage from the nozzle 10 to the electrode 76 arranged inside the cap 71 when the inkjet head 4 is driven to eject, but this is not limited to this.

[0132] For example, instead of electrode 76, the ejection inspection unit may have an electrode that extends vertically and faces the space below nozzle 10 when carriage 2 is positioned in the maintenance position, and inspect whether the nozzle is normal or abnormal based on the change in the voltage of the electrode output from signal processing circuit 78 when ejection driving is performed with carriage 2 positioned in the maintenance position.

[0133] Alternatively, the ejection inspection unit may have an optical sensor that directly detects ink ejected from the nozzle 10 when the carriage 2 is positioned at a predetermined position such as a maintenance position, and inspect whether the nozzle is normal or abnormal based on the detection results of this optical sensor.

[0134] Alternatively, the ejection inspection unit may inspect whether or not a nozzle is abnormal, for example, in the same manner as described in Japanese Patent No. 4929699. Specifically, the ejection inspection unit may connect a voltage detection circuit that detects a change in voltage when ink is ejected from a nozzle to a plate on which nozzles of an inkjet head are formed, and inspect whether a nozzle is normal or abnormal based on a signal output from the voltage detection circuit when an operation to eject ink from the nozzle is performed with the carriage moved to the inspection position.

[0135] Alternatively, the ejection inspection unit may inspect whether a nozzle is abnormal, for example, in the same manner as described in Japanese Patent No. 6231759. Specifically, the ejection inspection unit may be configured so that the substrate of the inkjet head is equipped with a temperature detection element, and after applying a first applied voltage to drive the heater in order to eject ink, it applies a second applied voltage to drive the heater so that ink is not ejected, and then inspects whether the nozzle is normal or abnormal based on changes in temperature detected by the temperature detection element over the period until a predetermined time has elapsed.

[0136] Alternatively, the discharge inspection unit may inspect whether or not a nozzle is abnormal in the same manner as described in, for example, Japanese Patent Application Laid-Open No. 2004-284189, Japanese Patent Application Laid-Open No. 2011-240563, etc. Specifically, in the case where the inkjet head is configured to eject ink from the nozzle by applying pressure to ink in a pressure chamber communicating with the nozzle using a piezoelectric element, the discharge inspection unit may be equipped with a residual vibration inspection device that detects residual vibrations that occur in the piezoelectric element due to pressure changes in the ink in the pressure chamber, and inspect whether a nozzle is normal or abnormal based on the vibration pattern of the residual vibrations detected when the piezoelectric element is driven to eject ink from the nozzle.

[0137] Furthermore, the printer is not necessarily equipped with a discharge inspection unit. For example, the printer may record a test pattern for inspecting whether each nozzle 10 is a normal nozzle or an abnormal nozzle, and each nozzle may be inspected for normal or abnormal based on the results of the test pattern recording. In this case, for example, the user may operate an operation unit (not shown) of the printer based on the results of the test pattern recording, thereby inputting the results of the test pattern recording to the control unit 80. Alternatively, if the printer is equipped with a scanner that reads images recorded on recording paper S, the recorded test pattern may be read by the scanner, thereby inputting the results of the test pattern recording.

[0138] In the above example, the nozzle 10 that ejects less ink than normal is determined to be an abnormal nozzle, but this is not limited to this. For example, the nozzle 10 that has another abnormality in ink ejection, such as a nozzle 10 that ejects ink in a misaligned direction, may also be determined to be an abnormal nozzle.

[0139] In the above example, the inkjet head 4 selectively ejects from the nozzles 10 one of four types of ink droplets, namely small droplets, medium droplets, large droplets, and extra-large droplets, each having a different ink volume, but this is not limiting. The inkjet head 4 may selectively eject from the nozzles 10 one of two, three, or five or more types of ink droplets each having a different ink volume.

[0140] Furthermore, in the above example, the number of nozzle rows N is 4, and the inkjet head 4 has four nozzle rows 9A to 9D. However, this is not limiting. The number of nozzle rows N may be 2, 3, or 5 or more, and the inkjet head may have two, three, or five or more nozzle rows. In these cases, each abnormal nozzle corresponds to a "first nozzle," and a nozzle row formed by multiple nozzles including the first nozzle corresponds to the "first nozzle row." Furthermore, if the number of nozzle rows in the inkjet head is N, the nozzle rows other than the first nozzle row correspond to (N-1) "Mth nozzle rows" for each of the (N-1) integers M between 2 and N. Furthermore, the nozzle 10 in each Mth nozzle row that is located in the same position in the transport direction as the abnormal nozzle in each Mth nozzle row corresponds to the "Mth nozzle." Alternatively, the inkjet head may have multiple nozzles lined up in the scanning direction, but may not have other nozzles lined up in the transport direction with each nozzle to form a nozzle row.

[0141] In the above example, the recording unit is configured with one inkjet head, but this is not limiting. For example, the recording unit may be configured with multiple inkjet heads mounted on a carriage.

[0142] Furthermore, although the above description has been given of an example of a printer equipped with a so-called serial head, which ejects ink from multiple nozzles while moving together with the carriage in the scanning direction, the present invention is not limited to this and can also be applied to, for example, a printer equipped with a so-called line head.

[0143] In a printer equipped with a line head, for example, the line head has a nozzle row formed by a plurality of nozzles arranged across the entire width of the recording paper in a direction perpendicular to the transport direction of the recording paper, and multiple such nozzle rows are lined up in the transport direction. In a printer equipped with a line head, the recording paper is transported in the transport direction by a transport mechanism (not shown) composed of rollers or the like, while ink is ejected toward the recording paper from the multiple nozzles of the line head. In this case, the transport direction corresponds to the "first direction," and the direction perpendicular to the transport direction and in which the multiple nozzles constituting each nozzle row are arranged corresponds to the "second direction." In this case, the transport mechanism that transports the recording paper in the transport direction corresponds to the "moving mechanism."

[0144] Although the above describes an example of a printer that ejects ink from nozzles to record on recording paper S, the present invention is not limited to this. The present invention can also be applied to image recording devices and image recording systems that record images on recording media other than recording paper, such as T-shirts, outdoor advertising sheets, cases for mobile devices such as smartphones, cardboard, and resin materials. The present invention can also be applied to image recording devices and image recording systems that record images by ejecting liquid other than ink droplets, such as liquid resin or metal liquid. [Explanation of symbols]

[0145] 1: Printer 2: Carriage 4: Inkjet head 9A to 9D: Nozzle rows 10: Nozzle 11,12: Guide rail 80: Control unit 84: Memory 86: Carriage motor 100: Image recording system 101: Printer 102: Control device 103: Storage section

Claims

1. a recording unit including a plurality of nozzles and configured to eject the same type of liquid from the plurality of nozzles; a moving mechanism that moves one of the recording unit and the recording medium in a first direction relative to the other of the recording unit and the recording medium; a storage unit that stores nozzle information regarding each nozzle of the recording unit, as to whether the nozzle is a normal nozzle that normally ejects liquid or an abnormal nozzle that has an abnormality in ejecting liquid; a control unit, N is an integer equal to or greater than 2, and the plurality of nozzles include a first nozzle to an Nth nozzle that are arranged at different positions in the first direction, The control unit controlling the movement mechanism to move one of the recording unit and the recording medium in the first direction relative to the other of the recording unit and the recording medium, while controlling the recording unit to execute a discharge process to discharge liquid from at least some of the first to Nth nozzles at timings when the positional relationships between the first to Nth nozzles and the recording medium in the first direction when discharging liquid are the same for the first to Nth nozzles; M is an integer of (N-1) between 2 and N, and if the nozzle information indicates that the first nozzle is the abnormal nozzle and at least one Mth nozzle is the normal nozzle, In the ejection process, An image recording device characterized by controlling the recording unit so that liquid is not ejected from the first nozzle, and the amount of liquid ejected from at least one of the M nozzles, which is the normal nozzle, is increased compared to when the first nozzle is the normal nozzle.

2. The control unit When the nozzle information indicates that the first nozzle is the abnormal nozzle and at least one of the M nozzles is the normal nozzle, In the ejection process, The image recording device described in claim 1, characterized in that the recording unit is controlled so that liquid is not ejected from the first nozzle, and the amount of liquid ejected from at least one of the M nozzles, which is the normal nozzle, is increased so that the total amount of liquid ejected from the M nozzle, which is the normal nozzle, is an amount within a specific range that includes the total amount of liquid ejected from the first nozzle to the Nth nozzle when the first nozzle is the normal nozzle.

3. N is an integer of 3 or more, The control unit When the nozzle information indicates that the first nozzle is the abnormal nozzle and the plurality of M nozzles are the normal nozzles, The image recording device described in claim 1, characterized in that, in the ejection process, the recording unit is controlled so that liquid is not ejected from the first nozzle, and the amount of liquid ejected from at least one of the multiple M nozzles that are the normal nozzles is increased compared to when the first nozzle is the normal nozzle.

4. The control unit When the nozzle information indicates that the first nozzle is the abnormal nozzle and the plurality of M nozzles are the normal nozzles, The image recording device described in claim 3, characterized in that in the ejection process, the recording unit is controlled so that liquid is not ejected from the first nozzle, and the amount of liquid ejected from at least one of the multiple M nozzles that are normal nozzles is increased more than when the first nozzle is the normal nozzle, so that the amount of liquid ejected from each of the multiple M nozzles that are normal nozzles is equal.

5. The control unit When the nozzle information indicates that the first nozzle is the abnormal nozzle and the plurality of M nozzles are the normal nozzles, In the ejection process, the recording unit is controlled to increase the amount of liquid ejected from one of the plurality of M nozzles that is the normal nozzle compared to when the first nozzle is the normal nozzle; and If the increase in the amount of liquid ejected from one of the plurality of M nozzles that is the normal nozzle is less than an amount within a specified range that includes the amount of liquid ejected from the first nozzle when the first nozzle is the normal nozzle, 4. The image recording device according to claim 3, wherein the recording unit is controlled to increase the amount of liquid ejected from another one of the plurality of M nozzles, which is the normal nozzle, compared to when the first nozzle is the normal nozzle.

6. The control unit When the nozzle information indicates that the first nozzle is the abnormal nozzle and the plurality of M nozzles are the normal nozzles, The image recording device described in claim 5, characterized in that in the ejection process, the recording unit is controlled to increase the amount of liquid ejected from the M nozzle, which is a normal nozzle whose positional relationship with the first nozzle satisfies a specific condition, in priority to the amount of liquid ejected from the M nozzle, which is a normal nozzle that does not satisfy the specific condition.

7. The control unit When the nozzle information indicates that the first nozzle is the abnormal nozzle and the plurality of M nozzles are the normal nozzles, In the ejection process, controlling the recording unit to increase the amount of liquid ejected from one of the plurality of M nozzles that is the normal nozzle compared to when the first nozzle is the normal nozzle; and when the increase in the amount of liquid ejected from one of the plurality of M nozzles that are normal nozzles is less than the amount within the specified range, control the recording unit to increase the amount of liquid ejected from each of the plurality of M nozzles that are normal nozzles in turn, compared to when the first nozzle is the normal nozzle, until the total amount of increase in the amount of liquid ejected from the M nozzles that have increased the amount of liquid ejected reaches the amount within the specified range, or until the amount of liquid ejected from all of the M nozzles that are normal nozzles has increased; and If the total increase in the liquid ejection amount for all of the M nozzles that are normal nozzles is less than the amount within the specified range, and the liquid ejection amount from one of the M nozzles that are normal nozzles after the increase is less than the maximum ejection amount that can be ejected from one of the M nozzles that are normal nozzles, 6. The image recording apparatus according to claim 5, wherein the amount of liquid ejected from one of the plurality of M nozzles that is the normal nozzle is further increased in the recording section.

8. The control unit acquiring image data including data of a plurality of pixels arranged in a third direction and a fourth direction intersecting the third direction; data of N pixels arranged consecutively in the third direction of the image data are assigned to the first to Nth nozzles, respectively; In the ejection process, controlling the recording unit to eject liquid from each of the first to Nth nozzles based on the data of the assigned pixels; When the nozzle information indicates that the first nozzle is the abnormal nozzle and the plurality of M nozzles are the normal nozzles, The image recording device described in claim 3, characterized in that in the ejection process, the recording unit is controlled to increase the amount of liquid ejected from the M nozzle, which is the normal nozzle, based on data of pixels whose positional relationship with the pixel assigned to the first nozzle when the first nozzle is the normal nozzle meets a specific condition, in preference to the amount of liquid ejected from the M nozzle, which is the normal nozzle, based on data of pixels that do not meet the specific condition.

9. The control unit When the nozzle information indicates that the first nozzle is the abnormal nozzle and the M nozzles to which the data of the plurality of pixels that satisfy the specific condition are assigned are the normal nozzles, In the ejection process, The image recording device according to claim 8, characterized in that the recording unit is controlled to uniformly increase the amount of liquid ejected from the plurality of M nozzles, which are the normal nozzles that eject liquid based on data of multiple pixels that satisfy the specific conditions.

10. The control unit When the nozzle information indicates that the first nozzle is the abnormal nozzle and the plurality of M nozzles are the normal nozzles, In the ejection process, The image recording device according to claim 8, characterized in that the recording unit is controlled to increase the amount of liquid ejected from the M nozzles, which are normal nozzles that eject liquid based on pixel data that meets the specific conditions, by giving priority to the M nozzles that eject a smaller amount of liquid.

11. The recording unit a first nozzle row to an N-th nozzle row in which a plurality of nozzles are arranged in a second direction intersecting the first direction; 2. The image recording apparatus according to claim 1, wherein the first nozzle row to the Nth nozzle row include the first nozzle to the Nth nozzle, respectively.

12. The image recording device according to claim 1, wherein the first nozzle to the Nth nozzle are arranged at the same position in the first direction.

13. a recording unit including a plurality of nozzles and configured to eject the same type of liquid from the plurality of nozzles; a moving mechanism that moves one of the recording unit and the recording medium in a first direction relative to the other of the recording unit and the recording medium, an image recording device, wherein N is an integer equal to or greater than 2, and the plurality of nozzles include a first nozzle to an Nth nozzle that are arranged at different positions in the first direction; a control device that controls the image recording device, the image recording device or the control device is provided with a storage unit that stores nozzle information regarding each nozzle of the recording unit, as to whether the nozzle is a normal nozzle that normally ejects liquid or an abnormal nozzle that has an abnormality in ejecting liquid, The control device controlling the movement mechanism to move one of the recording unit and the recording medium in the first direction relative to the other of the recording unit and the recording medium, while controlling the recording unit to execute a discharge process to discharge liquid from at least some of the first to Nth nozzles at timings when the positional relationships between the first to Nth nozzles and the recording medium in the first direction when discharging liquid are the same for the first to Nth nozzles; M is an integer of (N-1) between 2 and N, and if the nozzle information indicates that the first nozzle is the abnormal nozzle and at least one Mth nozzle is the normal nozzle, In the ejection process, An image recording system characterized by controlling the recording unit so that liquid is not ejected from the first nozzle, and the amount of liquid ejected from at least one of the M nozzles, which is the normal nozzle, is increased compared to when the first nozzle is the normal nozzle.

14. a recording unit including a plurality of nozzles and configured to eject the same type of liquid from the plurality of nozzles; a moving mechanism that moves one of the recording unit and the recording medium in a first direction relative to the other of the recording unit and the recording medium; a storage unit that stores nozzle information regarding each nozzle of the recording unit, as to whether the nozzle is a normal nozzle that normally ejects liquid or an abnormal nozzle that has an abnormality in ejecting liquid, a program for controlling an image recording device, wherein N is an integer equal to or greater than 2, and the plurality of nozzles include first to Nth nozzles arranged at different positions in the first direction; On the computer, controlling the movement mechanism to move one of the recording unit and the recording medium in the first direction relative to the other of the recording unit and the recording medium, while controlling the recording unit to execute a discharge process to discharge liquid from at least some of the first to Nth nozzles at timings when the positional relationships between the first to Nth nozzles and the recording medium in the first direction when discharging liquid are the same for the first to Nth nozzles; M is an integer of (N-1) between 2 and N, and if the nozzle information indicates that the first nozzle is the abnormal nozzle and at least one Mth nozzle is the normal nozzle, In the ejection process, A program that controls the printing unit to not eject liquid from the first nozzle, and to increase the amount of liquid ejected from at least one of the M nozzles that is the normal nozzle, compared to when the first nozzle is the normal nozzle.

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