Inkjet recording apparatus and inkjet recording method

Abstract

To provide an inkjet recording device and an inkjet recording method capable of preventing wasteful consumption of ink by reducing the number of times recovery processing is performed to recover from a defective nozzle state. [Solution] The control unit 10 of the inkjet recording device X1 comprises an abnormality determination unit 16 that determines which of a plurality of nozzles is defective and experiencing ejection problems; a nozzle position determination unit 17 that determines whether there is a normal nozzle adjacent to the defective nozzle; a complementation processing unit 18 that executes complementation processing to complement ink ejection from the defective nozzle with ink ejection from the normal nozzle based on the determination result by the nozzle position determination unit 17; and a recovery processing unit 19 that executes recovery processing to recover the defective nozzle based on the determination result.

Description

[Technical Field]

[0001] The present invention relates to an inkjet recording apparatus and an inkjet recording method. [Background technology]

[0002] An inkjet recording device that records an image on a sheet using an inkjet method includes a recording head having a plurality of nozzles formed on its discharge surface that discharge ink. The recording head discharges ink from the nozzles toward the sheet by applying a voltage to piezoelectric elements provided corresponding to each nozzle. In addition, in inkjet recording devices, the amount of ink discharged from the nozzles may become unstable or the nozzles may become clogged due to an increase in ink viscosity caused by the ink drying, etc. This can result in a decrease in the image quality of the printed matter printed by the inkjet recording device.

[0003] BACKGROUND ART Conventionally, there is known a printing device that compensates for non-ejection of ink due to a defective nozzle having an unstable ejection amount or a clogged ink flow path by ejecting ink from a normal nozzle (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2022-153978 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional inkjet recording devices, when the number of defective nozzles is equal to or greater than a threshold, nozzle recovery processes such as flushing and purging may be performed to restore the state of the defective nozzles. However, if the nozzle recovery process is performed based on the number of defective nozzles, even though there are defective nozzles that can be compensated for by ejection from normal nozzles, ink may be wasted.

[0006] An object of the present invention is to provide an inkjet recording apparatus and an inkjet recording method that can reduce the number of times recovery processing is performed to recover from a defective nozzle, thereby preventing wasteful consumption of ink. [Means for solving the problem]

[0007] An inkjet recording device according to one aspect of the present invention comprises a recording head having a plurality of nozzles formed on an ejection surface from which ink is ejected; a defective nozzle determination unit that determines which of the plurality of nozzles is experiencing ejection problems; a normal nozzle determination unit that determines whether there is a normal nozzle adjacent to the defective nozzle; and a control unit that, based on the determination result by the normal nozzle determination unit, executes either a complementation process that complements the ink ejection from the defective nozzle with ink ejection from the normal nozzle, or a recovery process that restores the defective nozzle.

[0008] An inkjet recording method according to another aspect of the present invention is a method applicable to an inkjet recording apparatus including a recording head having a plurality of nozzles formed on an ejection surface from which ink is ejected, the inkjet recording method comprising the steps of: a defective nozzle determination step of determining which of the plurality of nozzles is experiencing an ejection failure; a normal nozzle determination step of determining whether or not there is a normal nozzle adjacent to the defective nozzle; a process selection step of selecting, based on the determination result of the normal nozzle determination step, either a complement process for complementing ink ejection from the defective nozzle with ink ejection from the normal nozzle, or a recovery process for recovering the defective nozzle; and a process execution step of executing the process selected by the process selection step. [Effects of the Invention]

[0009] According to the present invention, it is possible to reduce the number of times the nozzle recovery process is performed, thereby preventing unnecessary consumption of ink. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of an inkjet recording apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the configuration of an inkjet recording apparatus according to an embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing the configuration of a printing unit of an inkjet printing apparatus according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the configuration of a recording section and a transport unit of an inkjet recording apparatus according to an embodiment of the present invention. [Figure 5] FIG. 5 is a diagram showing the configuration of a paper transport belt of an inkjet recording apparatus according to an embodiment of the present invention. [Figure 6] FIG. 6 is a block diagram showing the configuration of a control unit of an inkjet recording apparatus according to an embodiment of the present invention. [Figure 7] FIG. 7 is a circuit diagram showing a residual vibration detection unit provided in the print head of the inkjet printing apparatus according to the embodiment of the present invention. [Figure 8] FIG. 8 is a schematic diagram showing an example of the arrangement of defective nozzles and normal nozzles on the ejection surface of a print head of an inkjet printing apparatus according to an embodiment of the present invention. [Figure 9] FIG. 9 is a diagram showing the ink ejection amount when the complementary process is not performed and the ink ejection amount when the complementary process is performed. [Figure 10] FIG. 10 is a schematic diagram showing an example of the arrangement of defective nozzles, normal nozzles, and non-ejecting nozzles on the ejection surface of a print head of an inkjet printing apparatus according to an embodiment of the present invention. [Figure 11] FIG. 11 is a diagram showing the ink ejection amount when no complementary processing is performed and the ink ejection amount when complementary processing is performed. [Figure 12] FIG. 12 is a flowchart showing an example of the procedure of the image recording process executed by the control unit of the inkjet recording apparatus according to the embodiment of the present invention. [Figure 13]FIG. 13 is a flowchart showing another example of the procedure of the image recording process executed by the control unit of the inkjet recording apparatus according to the embodiment of the present invention. [Figure 14] FIG. 14 is a flowchart showing another example of the procedure of the image recording process executed by the control unit of the inkjet recording apparatus according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is merely an example of the present invention, and does not limit the technical scope of the present invention.

[0012] [Schematic configuration of inkjet recording device X1] First, the configuration of an inkjet recording apparatus X1 (hereinafter abbreviated as "recording apparatus X1") according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. Here, FIG. 1 shows a state in which the transport unit 5 of the recording apparatus X1 is disposed at a recording position where printing can be performed by the recording unit 3, and FIG. 2 shows a state in which the transport unit 5 is disposed at a maintenance position located a predetermined distance below the recording position. FIG. 3 is a plan view showing the configuration of the recording unit 3. FIG. 4 is a cross-sectional schematic view showing the configuration of the recording unit 3. FIG. 5 is a diagram showing the configuration of a transport belt 51. Note that FIG. 3 shows the recording unit 3 as viewed from above in FIG. 1.

[0013] The recording device X1 is a printer capable of recording images using an inkjet method. The present invention may also be applied to devices such as facsimile machines, copy machines, and multifunction peripherals that are capable of performing inkjet printing.

[0014] As shown in FIG. 1, the recording device X1 includes a paper feed cassette 1, a paper feed section 2, a recording section 3, an ink container section 4, a transport unit 5, a paper discharge section 6, a lifting mechanism 7, a purging device 8, a capping device 9, a control section 10, and a main body frame 1A that houses or supports these components.

[0015] Sheets to be printed by the recording device X1 are accommodated in the paper feed cassette 1. For example, the sheets accommodated in the paper feed cassette 1 are sheet materials such as paper, coated paper, postcards, envelopes, cloth, and overhead projector sheets.

[0016] The paper feed unit 2 supplies sheets stored in the paper feed cassette 1 to the recording unit 3. As shown in FIG. 1, the paper feed unit 2 includes a pickup roller 21, a transport roller 22, a transport path 23, a registration roller 24, a manual feed tray 25, and a paper feed roller 26. The pickup roller 21 picks up sheets one by one from the paper feed cassette 1. The transport roller 22 transports the sheets picked up by the pickup roller 21 to the registration roller 24. The transport path 23 is a path along which the sheets move from the paper feed cassette 1 and the manual feed tray 25 to the recording unit 3. The registration roller 24 transports the sheets to the recording unit 3 at a predetermined transport timing (image writing timing). The manual feed tray 25 and the paper feed roller 26 are used to supply sheets from the outside.

[0017] The recording unit 3 records an image on a sheet supplied from the paper feed unit 2. As shown in FIG. 1, the recording unit 3 includes line heads 31, 32, 33, and 34 corresponding to the colors black, cyan, magenta, and yellow, respectively, and a head frame 35 that supports these. The head frame 35 is supported by the main body frame 1A of the recording device X1. The number of line heads included in the recording unit 3 may be one or more.

[0018] The line heads 31 to 34 are so-called line head type recording units (recording devices). That is, the recording device X1 is a so-called line head type inkjet recording device that ejects ink droplets onto a sheet transported below the fixed line heads 31 to 34 to record an image on the sheet.

[0019] The line heads 31 to 34 are elongated in a width direction D2 (see FIG. 3) perpendicular to the sheet transport direction D1. Specifically, each of the line heads 31 to 34 has a length in the width direction D2 that corresponds to the width of the largest sheet that can be accommodated in the paper feed cassette 1. The line heads 31 to 34 are fixed to the head frame 35 at predetermined distances along the sheet transport direction D1.

[0020] As shown in FIG. 3, each of the line heads 31 to 34 has a plurality of recording heads 30 (one example of a recording head of the present invention). The recording head 30 has a plurality of nozzles 36 from which ink is ejected and a plurality of piezoelectric elements 302 (see FIG. 6) provided corresponding to each nozzle 36. The recording head 30 ejects ink toward a sheet transported by a transport belt 51 of a transport unit 5. Specifically, a large number of nozzles 36 having openings for ejecting ink are formed on an ink ejection surface 30A (see FIG. 1) of the recording head 30. The ink ejection surface 30A is the lower end surface of the recording head 30, and is the surface facing the recording surface of the sheet transported by the transport unit 5.

[0021] The recording head 30 also includes a plurality of pressure chambers (not shown) corresponding to the nozzles 36, a plurality of piezoelectric elements 302 (see FIG. 6) provided corresponding to the respective pressure chambers, and a communication flow path (not shown) communicating with each of the pressure chambers. The piezoelectric elements 302 eject ink from the nozzles 36 in response to input of a predetermined drive signal (control signal). For example, the drive signal is a clock signal having a predetermined voltage, frequency, and duty ratio. Specifically, the piezoelectric elements 302 pressurize the ink contained in the pressure chambers, thereby ejecting ink from the nozzles 36.

[0022] In the inkjet recording device X1 of this embodiment, during the printing process of an image on a sheet, the control unit 10 outputs a drawing drive signal (control signal) for causing the piezoelectric element 302 to eject ink from the head driver 301 (see Figure 6) described below to the piezoelectric element 302, and ejects drawing ink from the nozzle 36 at a predetermined drawing position on the sheet.

[0023] Furthermore, the control unit 10 causes a flushing drive signal (control signal) to be output from a head driver 301 (see FIG. 6) described below to the piezoelectric element 302 at a timing different from that during the image printing process, causing the piezoelectric element 302 to eject a predetermined specified amount of ink (ink ejection amount), thereby executing a flushing process (one example of a recovery process of the present invention) during a non-image printing period. The flushing process is a process in which the specified amount of ink is ejected from the nozzles 36 toward the opening group 512 (see FIG. 5) described below during the printing process. In this way, by performing the flushing process at a timing different from that during the printing process, ejection problems such as clogging of the nozzles 36 due to dried ink or the like are resolved.

[0024] In addition, in order to detect residual vibrations for each of the multiple nozzles 36, when a predetermined residual vibration detection timing arrives, the control unit 10 outputs a vibration generating drive signal from a head driver 301 (see Figure 6) described below corresponding to the multiple nozzles 36 to a piezoelectric element 302, thereby vibrating the peripheral portion of each nozzle 36.

[0025] The printhead 30 includes a head driver 301 (see FIG. 6). The head driver 301 controls the operation of each of the plurality of piezoelectric elements 302 included in the printhead 30. The head driver 301 generates the drive signal for each piezoelectric element 302 for controlling the operation of the piezoelectric element 302 based on pixel data input from the control unit 10, and controls the driving of each piezoelectric element 302 by outputting the generated drive signal to the corresponding piezoelectric element 302. Examples of the drive signal include the drawing drive signal, the flushing drive signal, and the vibration generation drive signal.

[0026] 3, three recording heads 30 are arranged in a staggered manner along the width direction D2 in the line head 31. Similarly to the line head 31, each of the other line heads 32 to 34 also has three recording heads 30 arranged in a staggered manner along the width direction D2.

[0027] 1, the ink container unit 4 includes ink containers 41, 42, 43, and 44, each containing ink corresponding to black, cyan, magenta, and yellow. The ink containers 41 to 44 are connected to line heads 31 to 34 of the same color via an ink supply unit (not shown). The line heads 31 to 34 are supplied with ink from the ink containers 41 to 44, respectively.

[0028] The transport unit 5 is disposed below the line heads 31 to 34. The transport unit 5 transports the sheet while aligning the recording surface (upper surface) of the sheet with the ink ejection surface 30A of the recording head 30.

[0029] 4, the transport unit 5 includes a transport belt 51 on which a sheet is placed, tension rollers 52 to 54 that tension the transport belt 51, and a transport frame 55 that supports these. The gap between the transport belt 51 and the ink ejection surface 30A is adjusted so that the gap between the recording surface of the sheet and the ink ejection surface 30A during printing processing is 1 mm, for example.

[0030] The conveyor belt 51 is an endless circular belt. The tension rollers 52 to 54 are disposed inside the conveyor belt 51.

[0031] The tension roller 52 is connected to the rotation shaft of a motor (not shown). When the tension roller 52 is rotated counterclockwise by the drive of the motor, the conveyor belt 51 rotates in a direction that allows the sheet to be conveyed in the conveying direction D1. As a result, the sheet supplied from the paper feed unit 2 is conveyed by the rotation of the conveyor belt 51 toward the paper discharge unit 6 via the recording unit 3. The conveying unit 5 also includes a suction unit (not shown) that sucks air through a number of through holes (not shown) formed in the conveyor belt 51 to attract the sheet to the conveyor belt 51. A pressure roller 56 is provided opposite the tension roller 53 to press the sheet against the conveyor belt 51 for conveyance.

[0032] 1, the paper discharge unit 6 is provided downstream of the recording unit 3 in the conveying direction D1. The paper discharge unit 6 includes a drying device 61, a conveying path 62, paper discharge rollers 63, and a paper discharge tray 64. The drying device 61 dries ink adhering to the sheet, for example, by blowing air onto the sheet. The sheet dried by the drying device 61 is then sent to the conveying path 62 and discharged to the paper discharge tray 64 by the paper discharge rollers 63.

[0033] As shown in FIG. 4, the transport unit 5 is provided with a sheet sensor 57. The sheet sensor 57 is provided downstream of the registration rollers 24 (see FIG. 1) in the transport direction D1 and upstream of the recording unit 3 in the transport direction D1. The sheet sensor 57 is disposed above the transport belt 51 so as to be able to detect the sheet being transported by the transport belt 51. The sheet sensor 57 is a sensor that detects the position of the sheet being transported by the transport belt 51. The control unit 10 controls the rotation of the registration rollers 24 based on a detection signal received from the sheet sensor 57, and sends the sheet toward the transport unit 5 at a predetermined timing in accordance with the timing of ink ejection from the recording heads 30. The control unit 10 also controls the ejection of ink from the nozzles 36 onto the sheet that has reached a position facing each of the recording heads 30 of each color by the transport belt 51.

[0034] The transport unit 5 is also provided with belt sensors 58 and 59. The belt sensor 58 is disposed downstream of the recording unit 3 in the transport direction D1 and above the transport belt 51. The belt sensor 59 is disposed inside the transport belt 51. The belt sensor 59 is disposed downstream of the pressure roller 56 in the transport direction D1 and upstream of the recording unit 3 in the transport direction D1. The belt sensors 58 and 59 are sensors for detecting the position of an opening group 512 (see FIG. 5 ), which is a collection of a plurality of openings 511 (described below) provided in the transport belt 51.

[0035] 5, the conveyor belt 51 has a plurality of openings 511 penetrating from the front to the back. The openings 511 are through-holes through which ink ejected from the recording heads 30 passes during flushing. The plurality of openings 511 are formed at positions and with sizes corresponding to the plurality of recording heads 30. A group of a plurality of openings 511 (for example, three openings) constitutes one opening group 512.

[0036] In this embodiment, a plurality of opening groups 512 are arranged at equal intervals at predetermined intervals in the conveyance direction D1. On the conveyance belt 51, a sheet to be printed is placed in the space between adjacent opening groups 512 in the conveyance direction D1. When the flushing process is performed by the control unit 10, the control unit 10 ejects ink from the nozzles 36 of the recording head 30 toward the opening groups 512 located between sheets (between the sheets) on the conveyance belt 51. The ejected ink passes through one of the openings 511 in the opening groups 512 and is discharged into an ink receiving unit 55A (see FIG. 4) described below.

[0037] 4, the recording device X1 is provided with a plurality of ink receiving units 55A. The ink receiving units 55A are attached to the transport frame 55. The ink receiving units 55A are disposed below the recording heads 30 and inside the transport belt 51. The ink receiving units 55A receive ink that has passed through the openings 511 of the transport belt 51 when the flushing process is performed.

[0038] 5, when sheets S are conveyed in order in the conveying direction D1 by the conveyor belt 51, the control unit 10 executes the flushing process based on preset flushing conditions at a predetermined timing toward the opening group 512 immediately preceding the sheet S, and then executes an image printing process on the sheet S upstream of the opening group 512. For example, when the control unit 10 executes the flushing process on the opening group 512A immediately preceding the sheet S1, the control unit 10 then executes an image printing process on the sheet S1 upstream of the opening group 512A.

[0039] The lifting mechanism 7 supports the transport unit 5 from below and raises and lowers the transport unit 5. The lifting mechanism 7 moves the transport unit 5 and the line heads 31 to 34 relatively to each other, thereby moving the transport unit 5 and the line heads 31 to 34 closer to and away from each other. Specifically, the lifting mechanism 7 moves the transport unit 5 between a recording position (position shown in FIG. 1) where printing by the recording unit 3 is possible, and a maintenance position (position shown in FIG. 2) that is a predetermined distance below the recording position.

[0040] 1, the lifting mechanism 7 includes four sets of eccentric cams 71 corresponding to the four corners of the bottom surface of the transport unit 5, and a rotary shaft 72. The eccentric cams 71 are rotatably supported by the rotary shaft 72, which is connected to the rotary shaft of a motor (not shown). The transport unit 5 is supported from below by the eccentric cams 71.

[0041] In the lifting mechanism 7, the rotation shaft 72 is rotationally driven by a motor (not shown), thereby rotating the eccentric cam 71. As a result, the transport unit 5 moves up and down.

[0042] For example, in Fig. 1, when the left eccentric cam 71 is rotated clockwise and the right eccentric cam 71 is rotated counterclockwise, the transport unit 5 gradually descends. Also, when the left eccentric cam 71 is rotated counterclockwise and the right eccentric cam 71 is rotated clockwise, the transport unit 5 gradually ascends.

[0043] 1 shows a state in which the transport unit 5 is disposed at the recording position closest to the line heads 31 to 34. When the transport unit 5 is at this recording position, the recording device X1 is capable of printing.

[0044] 2 shows the transport unit 5 in the maintenance position, which is the lowest position in the vertical direction and the furthest from the line heads 31 to 34. When the transport unit 5 is in this maintenance position, the user can remove any sheets remaining in the transport unit 5. Furthermore, when the transport unit 5 is in the maintenance position, a purge process (an example of a recovery process of the present invention) can be performed by the purge device 8, and capping can be performed by the cap device 9 to cover the nozzles 36 of the ink ejection surface 30A.

[0045] The purging device 8 is a device that recovers the function of the recording heads 30 of each of the line heads 31 to 34. As shown in FIG. 1, the purging device 8 has an ink tray 81 for receiving ink. The ink tray 81 is supported so as to be movable in the horizontal direction (left and right direction in FIG. 1) by a first movement mechanism (not shown). The first movement mechanism is, for example, a conventionally well-known drive mechanism that moves the ink tray 81 in the horizontal direction by using a rack and pinion mechanism that converts the rotational motion of a gear connected to the rotation shaft of a motor into linear motion.

[0046] The purge device 8 has an ink tray 81 that receives ink discharged from the nozzles 36 of each recording head 30, a plurality of wiper members (not shown) that clean each ink ejection surface 30A, and a carriage 82 that supports the ink tray 81 and the wiper members. The number of wiper members provided corresponds to the number of recording heads 30, specifically 12. The purge device 8 also has an electric purge pump 83 (see FIG. 6) that sucks ink from the nozzles 36 of each recording head 30. The purge pump 83 is provided, for example, in ink tubes (not shown) that extend from the ink containers 41-44 to the line heads 31-34, and increases the ink pressure in the ink tubes when driven.

[0047] The purge pump 83 is electrically connected to the control unit 10, and is driven in response to a drive signal output from the control unit 10, and stops when the drive signal is interrupted.

[0048] Normally (during printing), the carriage 82 of the purging device 8 is disposed at a first retracted position (position shown in FIG. 1) retracted downstream in the transport direction D1 from the recording unit 3. Then, when a command to perform a purging operation is input or the operating conditions for performing a purging operation are satisfied, the carriage 82 is moved by the first moving mechanism into the space created at the location opposite the line heads 31 to 34, with the transport unit 5 moved to the maintenance position by the lifting mechanism 7 (see the position shown by the dashed line in FIG. 2).

[0049] When the carriage 82 of the purge device 8 moves to a position facing the line heads 31 to 34, the lifting mechanism 7 raises the transport unit 5 a predetermined distance from the maintenance position. This positions the ink tray 81 of the purge device 8 at the purge position directly below the ink ejection surface 30A. When the ink tray 81 is positioned at the purge position, the control unit 10 performs a purge process. Specifically, the control unit 10 controls the drive of a purge pump 83 (see FIG. 6 ), causing ink to be discharged from the nozzles 36 of each recording head 30 toward the ink tray 81. The purge pump 83 is not limited to one that increases the ink pressure in the ink tubes connecting the ink containers 41 to 44 and the line heads 31 to 34. For example, if the ink tray 81 airtightly seals the ink ejection surface 30A, the purge pump 83 may be one that sucks ink from the nozzles 36 of the ink ejection surface 30A.

[0050] By carrying out the purging process, the highly viscous ink remaining in the nozzles 36 of each ink ejection surface 30A is discharged, thereby clearing clogging of the nozzles 36. The ink discharged into the ink tray 81 is discharged from a discharge port provided at the bottom of the ink tray 81 through an ink tube (not shown) to a predetermined waste ink storage section.

[0051] After the purging operation, the purge device 8 drives each of the wiper members (not shown) by a driving mechanism such as a motor to bring them into elastic contact with the ink ejection surface 30A. Specifically, each of the wiper members is moved in one direction while in elastic contact with the ink ejection surface 30A. As a result, the ink ejection surface 30A is wiped and cleaned by the wiper members. The ink wiped off by the wiper members falls downward along the wiper members and is collected in the ink tray 81. The purge device 8 is then returned from the purge position to the first retracted position.

[0052] The capping device 9 covers the nozzles 36 of each ink ejection surface 30A during non-printing periods to prevent the ink inside the nozzles 36 from drying out. As shown in FIG. 1, the capping device 9 has a capping member 91 that covers the nozzles 36 of each ink ejection surface 30A. The capping member 91 is supported by a second movement mechanism (not shown) so as to be movable in the horizontal direction (left-right direction in FIG. 1). Like the first movement mechanism, the second movement mechanism is a conventionally known drive mechanism that moves the capping member 91 in the horizontal direction using, for example, a rack-and-pinion mechanism that converts the rotational motion of a gear connected to the rotating shaft of a motor into linear motion. Note that it is also possible to adopt a configuration in which the first movement mechanism selectively moves the ink tray 81 and the capping member 91 without providing the second movement mechanism.

[0053] The capping device 9 has twelve capping members 91 that cover the nozzles 36 of each ink ejection surface 30A, and a carriage 92 that supports the twelve capping members 91. The carriage 92 is moved by the second moving mechanism, thereby moving the capping members 91 in the horizontal direction.

[0054] The twelve cap members 91 are provided corresponding to the respective ink ejection surfaces 30 A. That is, each ink ejection surface 30 A is covered by a corresponding cap member 91.

[0055] The carriage 92 of the capping device 9 is normally (during printing) disposed at a second retracted position (position shown in FIG. 1) downstream of the recording unit 3 in the transport direction D1 and below the first retracted position of the carriage 82 of the purging device 8. When a command to perform the capping operation is input or the operating conditions for performing the capping operation are satisfied, the transport unit 5 is moved to the maintenance position by the lifting mechanism 7, and the carriage 92 is moved by the second moving mechanism to a space created at the location facing the line heads 31 to 34 (position shown by the dashed line in FIG. 2). At this time, the purging device 8 is disposed at the first retracted position.

[0056] When the carriage 92 of the capping device 9 moves to a position facing the line heads 31 to 34, the lifting mechanism 7 raises the transport unit 5 from the maintenance position. At this time, the lifting mechanism 7 raises the carriage 92 to a capping position where the upper end of the peripheral wall of the capping member 91 comes into close contact with the ink ejection surface 30A. When the capping members 91 are placed in the capping position, all of the nozzles 36 on each ink ejection surface 30A are airtightly covered by the capping members 91. Hereinafter, the state in which the ink ejection surface 30A is airtightly covered by the capping members 91 will be referred to as the capping state.

[0057] Incidentally, in conventional inkjet recording devices, the presence or absence of defective nozzles is detected in order to recover from the defective state of nozzles 36 that are experiencing ejection problems, and if the number of defective nozzles is equal to or greater than a threshold value, recovery processes such as the flushing process and the purging process are carried out. However, even though it is possible to complement ejection to ejection positions corresponding to defective nozzles with ejection from normal nozzles, if the recovery processes are carried out based on the number of defective nozzles, a problem can arise in that ink is wasted.

[0058] In contrast to this, the recording apparatus X1 according to this embodiment can reduce the number of times the recovery process is performed, thereby preventing unnecessary consumption of ink, as will be explained below.

[0059] The control unit 10 will now be described with reference to Fig. 6. Fig. 6 is a block diagram showing the configuration of the control unit 10 of the recording device X1.

[0060] As shown in FIG. 6, the control unit 10 comprehensively controls the recording device X1. The control unit 10 includes control devices such as a CPU, a ROM, and a RAM (not shown). The CPU is a processor that executes various types of arithmetic processing. The ROM is a non-volatile storage unit that stores in advance information such as control programs for causing the CPU to execute various types of processing. The RAM is a volatile storage unit that is used as a temporary storage memory (work area) for the various types of processing executed by the CPU. In the control unit 10, the CPU executes the various control programs previously stored in the ROM. In this way, the recording device X1 is controlled by the control unit 10.

[0061] The control unit 10 includes a memory unit 11, a conversion processing unit 12, a generation processing unit 13, a signal processing unit 14, a drive control unit 15, a nozzle state determination unit 16, a nozzle position determination unit 17, a complement processing unit 18, and a recovery processing unit 19. The nozzle state determination unit 16 is an example of a defective nozzle determination unit of the present invention. The nozzle state determination unit 16 and the nozzle position determination unit 17 are examples of a property nozzle determination unit of the present invention. The complement processing unit 18 and the recovery processing unit 19 are examples of a control unit of the present invention.

[0062] The storage unit 11 is a non-volatile storage device that stores data, information, numerical values, and the like used in various processes executed by the CPU of the control unit 10 and the like.

[0063] The conversion processing unit 12 converts each pixel data included in the image data printed by the recording device X1 into either ejection pixel data corresponding to the ejection of ink from the nozzle 36 corresponding to the position in the main scanning direction of the pixel data in the image data, or non-ejection pixel data corresponding to the non-ejection of ink from the nozzle 36 corresponding to the position in the main scanning direction of the pixel data.

[0064] Here, the ejection pixel data is data corresponding to the drawing drive signal (hereinafter referred to as the first drive signal) that can cause the piezoelectric element 302 to eject ink from the nozzle 36 during image printing processing. Also, the non-ejection pixel data is data corresponding to the drawing drive signal (hereinafter referred to as the second drive signal) that cannot cause the piezoelectric element 302 to eject ink from the nozzle 36 during image printing processing.

[0065] When a continuous printing process is executed to sequentially print multiple pieces of image data, the generation processing unit 13 generates print data in which each piece of image data to be printed in the continuous printing process is arranged in printing order via sheet spacing data corresponding to the sheet spacing between the image data.

[0066] Specifically, the generation processing unit 13 generates the print data in which each of the image data converted by the conversion processing unit 12 is arranged in printing order via the sheet-to-sheet data. Here, the sheet-to-sheet data is data made up of the non-ejection pixel data. The sheet-to-sheet data may include data added upstream in the sub-scanning direction from the image data that is printed first in the continuous printing process, and data added downstream in the sub-scanning direction from the image data that is printed last in the continuous printing process.

[0067] The signal processing unit 14 outputs each piece of pixel data included in the print data input from the generation processing unit 13 to the drive control unit 15. Specifically, the signal processing unit 14 outputs each piece of pixel data included in the print data to the drive control unit 15 at predetermined time intervals, in order from the upstream side in the sub-scanning direction. The time interval is the drive interval of the head driver 301. The drive interval is the time required for the ink ejection position (pixel recording position) on the sheet transported by the transport unit 5 to move by one pixel downstream in the sub-scanning direction.

[0068] The drive control unit 15 controls the driving of each of the plurality of piezoelectric elements 302 corresponding to the plurality of nozzles 36, based on the pixel data input from the signal processing unit 14. The drive control unit 15 causes the head driver 301 to output the predetermined drive signal to the piezoelectric elements 302, thereby ejecting ink from the nozzles 36.

[0069] When printing processing is performed on a sheet, the drive control unit 15 causes the head driver 301 to output the drive signal corresponding to the pixel data input from the signal processing unit 14 to the piezoelectric element 302. For example, when the drive control unit 15 outputs the ejection pixel data to the head driver 301, the head driver 301 outputs the first drive signal corresponding to the ejection pixel data to the piezoelectric element 302. Furthermore, when the drive control unit 15 outputs the non-ejection pixel data to the head driver 301, the head driver 301 outputs the second drive signal corresponding to the non-ejection pixel data to the piezoelectric element 302.

[0070] In addition, when the flushing process is performed during the execution of the printing process, the drive control unit 15 outputs the flushing drive signal from the head driver 301 to the piezoelectric element 302 during the non-printing period when the printing process is not performed on the sheet, in order to eject a predetermined amount of ink from the nozzle 36.

[0071] Here, the non-printing period is a period during which the opening group 512 (see FIG. 5) on the conveyor belt 51, on which no sheet is placed, passes over the ink ejection surface 30A of the recording head 30. The timing at which the opening group 512 reaches a position below the ink ejection surface 30A (flushing timing) is determined by the control unit 10 based on information such as signals from the belt sensors 58 and 59, the conveyance speed of the conveyor belt 51, the elapsed time since the opening group 512 was detected, and the distance from each sensor.

[0072] In this embodiment, when the flushing timing arrives, the drive control unit 15 generates pixel data for flushing (flushing pixel data) corresponding to the flushing drive signal and outputs the flushing pixel data to the head driver 301. As a result, the head driver 301 outputs the flushing drive signal corresponding to the flushing pixel data to each piezoelectric element 302. As a result, the flushing process is executed during the non-printing period during execution of the print process.

[0073] Furthermore, when residual vibration detection timing arrives for detecting residual vibration for each nozzle 36, the drive control unit 15 causes the head driver 301 to output a vibration generating drive signal to the piezoelectric elements 302, causing the plurality of piezoelectric elements 302 corresponding to each nozzle 36 to vibrate. For example, when the residual vibration detection timing arrives, the drive control unit 15 generates pixel data for residual vibration detection (residual vibration detection pixel data) corresponding to the vibration generating drive signal and outputs the residual vibration detection pixel data to the head driver 301. As a result, the head driver 301 outputs the vibration generating drive signal corresponding to the residual vibration detection pixel data to each piezoelectric element 302. As a result, while maintaining a state in which ink is not ejected from the nozzle 36, each piezoelectric element 302 is driven, and the surrounding area of ​​each nozzle 36 vibrates.

[0074] In this embodiment, the timing for detecting the residual vibration may be, for example, when the average number of ejections from the nozzle 36 exceeds a predetermined number, when the operating time of the inkjet recording device X1 exceeds a predetermined set time, or when the number of printed sheets exceeds a predetermined set number.

[0075] That is, when the pixel data input from the drive control unit 15 is the ejection pixel data, the head driver 301 generates the first drive signal (the drawing signal) corresponding to the ejection pixel data and inputs the first drive signal to the piezoelectric element 302. Furthermore, when the pixel data from the drive control unit 15 is the non-ejection pixel data, the head driver 301 inputs the second drive signal (the drawing signal) to the piezoelectric element 302.

[0076] As a result, one or more pieces of image data included in the print data are printed.

[0077] In addition, when the pixel data input from the drive control unit 15 is the flushing pixel data, the head driver 301 generates the flushing drive signal corresponding to the flushing pixel data and inputs the flushing drive signal to the piezoelectric element 302.

[0078] As a result, the flushing process is executed during the non-printing period.

[0079] In addition, when the pixel data input from the drive control unit 15 is the residual vibration detection pixel data, the head driver 301 generates the vibration generating drive signal corresponding to the residual vibration detection pixel data and inputs the vibration generating drive signal to the piezoelectric element 302 corresponding to the nozzle 36.

[0080] As a result, while the state in which ink is not ejected from the nozzles 36 is maintained, the piezoelectric elements 302 corresponding to the nozzles 36 are driven, and the peripheral portions of all the nozzles 36 vibrate.

[0081] The nozzle state determination unit 16 determines whether the state of each nozzle 36 is normal or abnormal. The nozzle state determination unit 16 calculates the ink viscosity, which indicates the viscosity of the ink inside each nozzle 36, and performs processing to determine whether each nozzle 36 is abnormal or not.

[0082] The nozzle state determination unit 16 measures the viscosity of the ink inside each nozzle 36. The nozzle state determination unit 16 performs processing to determine the viscosity of the ink inside each nozzle 36 based on a vibration signal indicating residual vibration detected by a residual vibration detection unit 310, which will be described later. The vibration signal is input from the residual vibration detection unit 310 to the control unit 10.

[0083] The viscosity of the ink inside the nozzles 36 can be measured, for example, by measuring the viscosity of the ink inside multiple nozzles 36 in advance through experiments, obtaining the amplitude and period of the vibration signal, and measuring measurement data in advance that indicates the correspondence between the measured viscosity and the amplitude and period. This measurement data is prepared for each nozzle 36, and a large number of measurement data are prepared for each nozzle 36. The nozzle state determination unit 16 uses this measurement data as a lookup table to obtain the amplitude and period of the vibration signal of the piezoelectric element 302 corresponding to the nozzle 36 to be measured, thereby obtaining the viscosity of the ink inside the nozzle 36 from the measurement data. Note that such determination methods are conventionally known, so a detailed description thereof will be omitted here.

[0084] If the measured viscosity exceeds a predetermined reference viscosity, the nozzle state determination unit 16 determines that the state of the ink inside the corresponding nozzle 36 is abnormal, and determines that the nozzle 36 is a defective nozzle that is experiencing ejection defects. On the other hand, if the measured viscosity is less than the reference viscosity, the nozzle state determination unit 16 determines that the nozzle 36 is a normal nozzle. Hereinafter, among the multiple nozzles 36, a nozzle that is experiencing ejection defects may be referred to as a defective nozzle 36A, and a normal nozzle may be referred to as a normal nozzle 36B.

[0085] The nozzle position determination unit 17 determines whether or not there is a normal nozzle 36B in a position adjacent to the defective nozzle 36A determined by the nozzle state determination unit 16 to have an ejection defect.

[0086] 8 is a schematic diagram showing an example of the arrangement of faulty nozzles 36A (portions indicated by dotted circles) and normal nozzles 36B (portions indicated by solid circles) on the ink ejection surface 30A. In the example of FIG. 8, in a printing process in which ink is ejected from all nozzles 36, the nozzle position determination unit 17 determines whether normal nozzles 36B are present at six adjacent nozzle positions surrounding a faulty nozzle 36A1 of interest. In other words, the nozzle position determination unit 17 determines whether normal nozzles 36B are present among the six nozzles 36 surrounding the faulty nozzle 36A1.

[0087] In another embodiment of the nozzle position determination unit 17, when the nozzle position determination unit 17 determines that normal nozzles 36B are present at six adjacent nozzle positions surrounding the defective nozzle 36A1 of interest, the nozzle position determination unit 17 further determines whether the number of normal nozzles 36B is equal to or greater than a predetermined set number (threshold value).

[0088] The complementation processing unit 18 performs a complementation process in which ink ejection by the defective nozzle 36A is complemented by ink ejection by the other normal nozzle 36B adjacent to the defective nozzle 36A.

[0089] For example, in region N1 in Fig. 8, the complement processing unit 18 performs a process of complementing one faulty nozzle 36A1 by ejecting ink from the surrounding normal nozzles 36B. Specifically, as shown in Fig. 9A, when ink is not ejected from the faulty nozzle 36A1, the ejection amount of the three surrounding normal nozzles 36B is increased, thereby rendering the pixel position on the sheet corresponding to the faulty nozzle 36A1 with ink ejected from the normal nozzles 36B. Note that the left diagram in Fig. 9A schematically shows the ink ejection amount when complement processing is not performed, and the right diagram in Fig. 9A schematically shows the ink ejection amount when complement processing is performed.

[0090] 8, the complementation processing unit 18 performs a process of complementing the three faulty nozzles 36A2-36A4 with the ejection of ink from the surrounding normal nozzles 36B. Specifically, as shown in FIG. 9B, when ink is not ejected from the faulty nozzles 36A2-36A4, the ejection amount of the seven surrounding normal nozzles 36B is increased, thereby rendering each pixel position on the sheet corresponding to the faulty nozzles 36A2-36A4 with ink ejected from the normal nozzles 36B. Note that the left diagram in FIG. 9B schematically shows the ink ejection amount when complementation processing is not performed, and the right diagram in FIG. 9B schematically shows the ink ejection amount when complementation processing is performed.

[0091] The amount of ink increased in the supplementary process is determined by the arrangement interval of the nozzles 36, the nozzle diameter, and the like.

[0092] In this embodiment, the complementation processing unit 18 performs the complementation processing based on the determination result by the nozzle position determination unit 17 .

[0093] Specifically, the complementation processing unit 18 executes the complementation processing when the nozzle position determination unit 17 determines that a normal nozzle 36B is located adjacent to the defective nozzle 36A of interest.

[0094] In another embodiment of the complementation processing unit 18, the complementation processing may be performed when the nozzle position determination unit 17 determines that there is a normal nozzle 36B at a position adjacent to the defective nozzle 36A of interest, and the number of normal nozzles 36B at that position is equal to or greater than the predetermined set number (threshold value). Note that the set number is a setting value that can be set arbitrarily, and in this embodiment, it is set to, for example, two or three.

[0095] The recovery processing unit 19 performs recovery processing (nozzle recovery processing) to recover the state of the ink inside the nozzle 36 that has been determined to be the defective nozzle by the nozzle state determination unit 16. In this embodiment, the recovery processing is performed based on the determination result by the nozzle position determination unit 17.

[0096] Specifically, the recovery processing unit 19 executes the recovery processing when the nozzle position determination unit 17 determines that there is no normal nozzle 36B in a position adjacent to the defective nozzle 36A of interest.

[0097] As another embodiment of the recovery processing unit 19, the recovery processing may be executed when the nozzle position determination unit 17 determines that there is a normal nozzle 36B at a position adjacent to the defective nozzle 36A of interest, and the number of normal nozzles 36B at that position is less than the predetermined set number (threshold value).

[0098] The set number is set to a value that makes it possible to determine whether or not the pixel position on the sheet corresponding to the faulty nozzle 36A can be drawn with ink ejected from the normal nozzle 36B through the complementation process.

[0099] 10A and 10B are schematic diagrams showing an example of the arrangement of defective nozzles 36A (portions indicated by dotted circles) and normal nozzles 36B (portions indicated by solid circles) on the ink ejection surface 30A.

[0100] For example, in the example shown in Figure 10(A), suppose five defective nozzles 36A are clustered in region N3. In this state, if a solid image printing process is performed in which ink is ejected from all nozzles 36, even if the interpolation process is performed, the number of normal nozzles 36B adjacent to the defective nozzles 36A is less than the set value, so ink will not be ejected at each pixel position on the sheet corresponding to the defective nozzles 36A (see Figure 11(A)). Therefore, in this case, the recovery process by the recovery processing unit 19 is executed before the printing process is performed.

[0101] 10B, five faulty nozzles 36A are concentrated in region N3, and adjacent to these faulty nozzles 36A are non-ejecting nozzles 36C (shown by black circles) that do not eject ink because there is no pixel data to be drawn. In this state, when a non-solid image is printed at pixel positions on the sheet corresponding to the non-ejecting nozzles 36C, even if the compensation process is performed, ink will not be ejected at each pixel position on the sheet corresponding to the faulty nozzles 36A because the number of normal nozzles 36B adjacent to the faulty nozzles 36A is less than the set value (see FIG. 11B). Therefore, in this case as well, the recovery process is performed by the recovery processing unit 19 before the printing process is performed. In this case, if the normal nozzles 36B determined to be normal are non-ejecting nozzles 36C corresponding to the non-image region, the nozzle position determination unit 17 does not determine the non-ejecting nozzles 36C as normal nozzles 36B but excludes them from the normal nozzles 36B.

[0102] Note that the recovery processing unit 19 may execute the purge process, which has a higher nozzle recovery effect and maintenance effect than the flushing process, for example, when the nozzle position determination unit 17 determines that there are no normal nozzles 36B adjacent to the target defective nozzle 36A. The recovery processing unit 19 may also execute the flushing process when it determines that there are normal nozzles 36B adjacent to the target defective nozzle 36A, and the number of normal nozzles 36B is less than the predetermined set number (threshold value). Note that the purge process is executed, for example, when printing processing is in progress, after all printing processing has finished, or while the printing processing is suspended.

[0103] As shown in Figure 6, the recording head 30 is provided with a residual vibration detection unit 310. The residual vibration detection unit 310 detects residual vibrations generated by the driving of piezoelectric elements 302, which correspond to a plurality of nozzles 36 on the recording head 30, after the piezoelectric elements 302 have been driven.

[0104] 7 is a circuit diagram showing the residual vibration detection unit 310. As shown in FIG. 7, the residual vibration detection unit 310 includes a switch circuit 311 and a vibration detection circuit 312.

[0105] The switch circuit 311 is a switch circuit that connects the piezoelectric element 302 to either the head driver 301 or the vibration detection circuit 312. Although one vibration detection circuit 312 is shown in Fig. 7, in reality, a plurality of vibration detection circuits 312 corresponding to each piezoelectric element 302 are provided.

[0106] The switch circuit 311 normally connects the piezoelectric element 302 and the head driver 301, and when detecting residual vibrations caused by driving the piezoelectric element 302, a control signal from the control unit 10 switches the contact to the vibration detection circuit 312 side.

[0107] The vibration detection circuit 312 rectifies the waveform of the residual vibration of the piezoelectric element 302 into a square wave and outputs it to the control unit 10. As shown in Fig. 7, the vibration detection circuit 312 is a conventionally known circuit that is composed of two capacitors C1 and C2, two resistors R1 and R2, an amplifier 3121, and a comparator 3122.

[0108] Hereinafter, an example of the procedure of the image recording process executed by the inkjet recording apparatus X1 will be described with reference to the flowcharts of Figures 12 to 14, and the inkjet recording method of the present invention shown in the flowcharts of Figures 12 to 14 will be described.

[0109] First, in step S11, the control unit 10 determines whether it is time to detect residual vibration.

[0110] When it is determined that the residual vibration detection timing has arrived, the control unit 10 vibrates the piezoelectric element 302 (S12). Specifically, the drive control unit 15 outputs the residual vibration detection pixel data to the head driver 301 of each recording head 30. The head driver 301 then generates the vibration generation drive signal corresponding to the residual vibration detection pixel data and outputs it to all the piezoelectric elements 302 of the recording head 30. As a result, the piezoelectric elements 302 are driven while the state in which ink is not ejected from the nozzles 36 is maintained, and the peripheral parts of the multiple nozzles 36 vibrate.

[0111] In the next step S13, the control unit 10 determines whether a predetermined set time has elapsed since the piezoelectric element 302 was vibrated. The set time is the elapsed time for measuring the residual vibration around the piezoelectric element 302.

[0112] Once the set time has elapsed, in the next step S14, the control unit 10 activates all the selector switches of the switch circuit 311 to switch the contacts to the vibration detection circuit 312. As a result, all vibrations (residual vibrations) generated around the piezoelectric elements 302 are input to the vibration detection circuit 312. When vibration is input to the vibration detection circuit 312, the vibration detection circuit 312 inputs a vibration signal, which is a rectangular wave obtained by rectifying the waveform of the input residual vibration, to the nozzle state determination unit 16.

[0113] In step S15, the control unit 10 determines whether the nozzle 36 of interest is a defective nozzle 36A or a normal nozzle 36B based on the vibration signal indicating residual vibration input from the vibration detection circuit 312. Specifically, the control unit 10 identifies the amplitude or period based on the waveform of the vibration signal and determines the viscosity of the ink inside each nozzle 36 based on the amplitude and period. The control unit 10 then determines whether the nozzle 36 of interest is a defective nozzle 36A or a normal nozzle 36B based on this viscosity. If the viscosity is equal to or greater than the reference viscosity, the control unit 10 determines that the viscosity of the ink in the nozzle 36 of interest is excessively high and that the nozzle 36 is experiencing ejection defects. In other words, the control unit 10 determines that the nozzle 36 is in an abnormal state, i.e., is a defective nozzle 36A. On the other hand, if the viscosity is less than the reference viscosity, the control unit 10 determines that the viscosity of the ink in the nozzle 36 of interest is appropriate and that the nozzle 36 is normal. In other words, the control unit 10 determines that the nozzle 36 of interest is a normal nozzle 36B. This determination process is performed for all the nozzles 36.

[0114] If it is determined in the determination process of step S15 that there is a faulty nozzle 36A (S16 Yes), the control unit 10 determines whether there is a normal nozzle 36B at the nozzle position adjacent to the faulty nozzle 36A (S17). Note that steps S15 and S16 are an example of a faulty nozzle determination step of the present invention. Also, steps S15 and S17 are an example of a normal nozzle determination step of the present invention.

[0115] If it is determined in step S16 that there is no defective nozzle 36A, then the control unit 10 executes the printing process (S20).

[0116] If it is determined in step S17 that there is a normal nozzle 36B, the control unit 10 performs the compensation process for the defective nozzle 36A. Specifically, the control unit 10 increases the set amount of ink ejection for the normal nozzle 36B adjacent to the defective nozzle 36A above the reference value. Thereafter, the printing process is executed (S20).

[0117] On the other hand, if it is determined in step S17 that there are no normal nozzles 36B, the control unit 10 performs the recovery process without performing the supplementary process. After that, when the recovery process is completed, the printing process is executed (S20).

[0118] In addition, as another embodiment of the image recording process, as shown in Figure 13, after it is determined in step S17 that there is a normal nozzle 36B, the control unit 10 may determine whether the normal nozzle is the non-discharging nozzle 36C (S171), and if it is the non-discharging nozzle 36C, it may be excluded from the normal nozzle 36B determined in step S17 (S172). In this case, if there is no normal nozzle 36B adjacent to the defective nozzle 36A after exclusion (No in S173), the control unit 10 performs the recovery process (S19). On the other hand, if there is a normal nozzle 36B adjacent to the defective nozzle 36A after exclusion (Yes in S173), the control unit 10 performs the compensation process for the defective nozzle 36A (S18).

[0119] Furthermore, as another embodiment of the image recording process, as shown in Figure 14, after it is determined in step S17 that there are normal nozzles 36B, the control unit 10 may determine whether the number of such normal nozzles is equal to or greater than the set number (S174). In this case, if the number of such normal nozzles is less than the set number, the control unit 10 performs the recovery process (S19). On the other hand, if the number of normal nozzles is equal to or greater than the set number, the interpolation process is performed appropriately, so the control unit 10 performs the interpolation process (S18).

[0120] The determination process of step S174 may be performed after step S173 in FIG.

[0121] As explained above, in the embodiment of the present invention, the image recording process described above is performed, and the recovery process is performed when the pixel position on the sheet corresponding to the faulty nozzle 36A cannot be imaged with ink ejected from the normal nozzles 36B even after the supplementary process. Therefore, compared to the conventional method in which the recovery process is performed based on the number of faulty nozzles 36A, the number of times the recovery process is performed is reduced, preventing ink from being wasted. In other words, it is possible to prevent ink from being wasted.

[0122] [Notes on the Invention] The following is a summary of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0123] <Appendix 1> A recording head having multiple nozzles on its ejection surface from which ink is ejected, A defective nozzle determination unit for determining which of the plurality of nozzles is causing a discharge failure, A normal nozzle determination unit that determines whether or not there is a normal nozzle adjacent to the defective nozzle, an inkjet recording device comprising: a control unit that executes either a complementary process that complements ink ejection from the defective nozzle with ink ejection from the normal nozzle, or a recovery process that recovers the defective nozzle, based on the judgment result by the normal nozzle judgment unit.

[0124] <Appendix 2> The control unit An inkjet recording apparatus as described in Appendix 1, wherein the normal nozzle determination unit executes the complementation process when it determines that there is a normal nozzle, and executes the recovery process when it determines that there is no normal nozzle.

[0125] <Appendix 3> The control unit executes the complementation process when the normal nozzle determination unit determines that there are normal nozzles and the number of normal nozzles is equal to or greater than a predetermined threshold value; 2. The inkjet recording apparatus according to claim 1, wherein the recovery process is executed when the normal nozzle determination unit determines that there are no normal nozzles, or when the number of normal nozzles is less than the threshold value.

[0126] <Appendix 4> An inkjet recording device according to any one of appendices 1 to 3, wherein, if a nozzle determined to be a normal nozzle is a non-ejecting nozzle corresponding to a non-image area, the normal nozzle determination unit does not determine the non-ejecting nozzle to be a normal nozzle and excludes the non-ejecting nozzle from the normal nozzles.

[0127] <Appendix 5> A method applied to an inkjet recording apparatus having a recording head having a plurality of nozzles formed on an ejection surface from which ink is ejected, comprising: a defective nozzle determination step of determining a defective nozzle that is causing an ejection defect among the plurality of nozzles; a normal nozzle determination step of determining whether there is a normal nozzle adjacent to the faulty nozzle; a process selection step of selecting, based on the determination result of the normal nozzle determination step, either a complement process for complementing ink ejection from the faulty nozzle with ink ejection from the normal nozzle, or a recovery process for recovering the faulty nozzle; a process execution step of executing the process selected by the process selection step; The inkjet recording method is carried out by one or more processors. [Explanation of symbols]

[0128] X1: Inkjet recording device 1: Paper feed cassette 2:Paper feed section 3: Records Department 4: Ink container section 5: Conveyor Unit 6: Paper output section 7: Lifting mechanism 8: Purge device 9: Capping device 10: Control section 11: Storage section 12: Conversion processing section 13: Generation processing section 14: Signal processing section 15: Drive control unit 16: Nozzle status determination unit 17: Nozzle position determination unit 18: Complement processing section 19: Recovery processing section 30: Recording head 30A: Ink ejection surface 31-34: Line Head 36: Nozzle 36A: Defective nozzle 36A1: Defective nozzle 36A2: Defective nozzle 36B: Normal nozzle 36C: Non-discharging nozzle 301: Head Driver 302: Piezoelectric element 310: Residual vibration detection unit 311: Switch Circuit 312: Vibration detection circuit

Claims

1. a recording head having a plurality of nozzles formed on an ejection surface for ejecting ink; a defective nozzle determination unit that determines a defective nozzle that is causing an ejection defect among the plurality of nozzles; a normal nozzle determination unit that determines whether there is a normal nozzle adjacent to the faulty nozzle; an inkjet recording device comprising: a control unit that executes either a complementary process that complements ink ejection from the defective nozzle with ink ejection from the normal nozzle, or a recovery process that recovers the defective nozzle, based on the judgment result by the normal nozzle judgment unit.

2. The control unit 2. The inkjet recording apparatus according to claim 1, wherein the complementing process is executed when the normal nozzle determination unit determines that there is a normal nozzle, and the recovery process is executed when the normal nozzle determination unit determines that there is no normal nozzle.

3. The control unit executes the complementation process when the normal nozzle determination unit determines that there are normal nozzles and the number of normal nozzles is equal to or greater than a predetermined threshold value; 2. The inkjet recording apparatus according to claim 1, wherein the recovery process is executed when the normal nozzle determination unit determines that there are no normal nozzles, or when the number of normal nozzles is less than the threshold value.

4. 3. The inkjet recording apparatus according to claim 1, wherein if a nozzle determined to be a normal nozzle is a non-ejecting nozzle corresponding to a non-image area, the normal nozzle determination unit does not determine the non-ejecting nozzle as a normal nozzle and excludes the non-ejecting nozzle from the normal nozzles.

5. A method applied to an inkjet recording apparatus having a recording head having a plurality of nozzles formed on an ejection surface from which ink is ejected, comprising: a defective nozzle determination step of determining a defective nozzle that is causing an ejection defect among the plurality of nozzles; a normal nozzle determination step of determining whether there is a normal nozzle adjacent to the faulty nozzle; a process selection step of selecting, based on the determination result of the normal nozzle determination step, either a complement process for complementing ink ejection from the faulty nozzle with ink ejection from the normal nozzle, or a recovery process for recovering the faulty nozzle; a process execution step of executing the process selected by the process selection step; The inkjet recording method is carried out by one or more processors.

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