Image forming device and nozzle inspecting method

Abstract

To provide an image forming device and a nozzle inspecting method which can improve accuracy in determining whether there is a nozzle whose track is curved or not.SOLUTION: An image forming device 1 is provided with: a formation processing part 21 that forms, on a sheet, images for obtaining which include a first image for obtaining used to obtain the number of nozzles in an abnormal state and a second image for obtaining used to obtain the number of nozzles in a non-discharge state; a reading processing part 22 that reads out the images for obtaining formed on the sheet; an obtaining processing part 23 that obtains the number of the nozzles in the abnormal state and the number of the nozzles in the non-discharge state, on the basis of a read result by the reading processing part 22; and a determining processing part 24 that determines whether there are the nozzles whose track is curved or not, on the basis of an obtained result by the obtaining processing part 23.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and a nozzle inspection method. [Background technology]

[0002] An image forming apparatus that forms an image using an inkjet method includes a discharge unit such as a line head. The discharge unit includes a plurality of nozzles arranged along a width direction perpendicular to a sheet conveyance direction, and discharges ink from each of the nozzles.

[0003] Also, an image forming apparatus capable of determining whether or not there is an abnormal nozzle is known as related art (see Patent Document 1). Specifically, in the image forming apparatus according to the related art, the ejection unit is used to form a first determination image used to determine whether or not there is an abnormal nozzle, and a second determination image used to determine whether or not there is a nozzle in a non-ejection state, which is unable to eject ink, among the abnormal states. Then, based on the results of reading the formed first determination image, the presence or absence of the abnormal nozzle is determined. Furthermore, if it is determined that there is an abnormal nozzle, based on the results of reading the formed second determination image, it is determined whether there is a non-ejection nozzle or a nozzle in a curved trajectory, in which the trajectory of ejected ink is curved. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-23459 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the image forming apparatus according to the related art, it is determined that the nozzle in the trajectory bending state exists only when it is determined that the nozzle in the abnormal state exists and the nozzle in the non-ejection state does not exist, and therefore, when both the nozzle in the non-ejection state and the nozzle in the trajectory bending state exist, it cannot be determined that the nozzle in the trajectory bending state exists.

[0006] An object of the present invention is to provide an image forming apparatus and a nozzle inspection method that can improve the accuracy of determining whether or not there are nozzles with a curved trajectory. [Means for solving the problem]

[0007] According to one aspect of the present invention, an image forming apparatus includes a discharge unit, a formation processing unit, a reading processing unit, an acquisition processing unit, and a determination processing unit. The discharge unit includes a plurality of nozzles arranged along a width direction perpendicular to a sheet conveyance direction, and causes ink to be ejected from each of the nozzles. The formation processing unit uses the discharge unit to form acquisition images on the sheet, including a first acquisition image used to acquire the number of nozzles in an abnormal state and a second acquisition image used to acquire the number of nozzles in a non-ejection state, which is one of the abnormal states. The reading processing unit reads the acquisition images formed on the sheet. The acquisition processing unit acquires the number of nozzles in an abnormal state and the number of nozzles in a non-ejection state, based on the reading result by the reading processing unit. The determination processing unit determines whether or not any nozzles are in a trajectory bending state, which is one of the abnormal states, are present, based on the acquisition result by the acquisition processing unit.

[0008] A nozzle inspection method according to another aspect of the present invention is executed by an image forming apparatus including a plurality of nozzles arranged along a width direction perpendicular to the sheet conveyance direction and an ejection unit that ejects ink from each of the nozzles, and includes a forming step, a reading step, an acquisition step, and a determination step. In the forming step, the ejection unit is used to form acquisition images on the sheet, including a first acquisition image used to acquire the number of nozzles in an abnormal state and a second acquisition image used to acquire the number of nozzles in a non-ejection state, which is one of the abnormal states. In the reading step, the acquisition images formed on the sheet are read. In the acquisition step, the number of nozzles in an abnormal state and the number of nozzles in a non-ejection state are acquired based on the reading result in the reading step. In the determination step, it is determined whether or not there are any nozzles in a trajectory bending state, which is one of the abnormal states, based on the acquisition result in the acquisition step. [Effects of the Invention]

[0009] According to the present invention, it is possible to improve the accuracy of determining whether or not there is a nozzle in a curved trajectory. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing the configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view showing the configuration of the image forming section and the transport unit of the image forming apparatus according to the embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view showing the configuration of the periphery of a nozzle of the image forming apparatus according to the embodiment of the present invention. [Figure 4] FIG. 4 is a block diagram showing the system configuration of the image forming apparatus according to the embodiment of the present invention. [Figure 5] FIG. 5 is a diagram showing an example of a capture image formed by the image forming apparatus according to the embodiment of the present invention. [Figure 6] FIG. 6 is a flowchart showing an example of a nozzle inspection process executed in the image forming apparatus according to the embodiment of the present invention. [Figure 7] FIG. 7 is a block diagram showing the system configuration of an image forming apparatus according to another 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 accompanying drawings. Note that the following embodiment is an example of a specific embodiment of the present invention and does not limit the technical scope of the present invention.

[0012] [Configuration of image forming apparatus 1] First, the configuration of an image forming apparatus 1 according to an embodiment of the present invention will be described with reference to Figures 1 to 4. In Figure 1, a sheet transport path R11 is indicated by a two-dot chain line.

[0013] The image forming apparatus 1 is a printer capable of forming an image on a sheet by inkjet printing. Note that the image forming apparatus 1 may also be a fax machine, a copier, a multifunction peripheral, or the like capable of forming an image on a sheet by inkjet printing.

[0014] 4, the image forming apparatus 1 includes a control unit 11, a sheet conveying unit 12, an image forming unit 13, a conveying unit 14, an operation display unit 15, a communication unit 16, and an image reading unit 17. The image forming apparatus 1 also includes a housing 1A shown in FIG.

[0015] The housing 1A houses each component of the image forming apparatus 1. A paper feed cassette 1B is removably provided in the housing 1A. Sheets on which images are formed are stored in the paper feed cassette 1B. A paper output tray 1C is provided on the outer surface of the housing 1A. Sheets on which images are formed by the image forming unit 13 are discharged to the paper output tray 1C. Inside the housing 1A, the sheets stored in the paper feed cassette 1B are transported along a sheet transport path R11 (see Figure 1) that passes through an image formation position by the image forming unit 13 and leads to the paper output tray 1C.

[0016] The control unit 11 performs overall control of the image forming apparatus 1. As shown in FIG. 4, the control unit 11 includes a CPU 11A, a ROM 11B, and a RAM 11C. The CPU 11A is a processor that executes various types of arithmetic processing. The ROM 11B is a non-volatile storage device that stores in advance information such as control programs for causing the CPU 11A to execute various types of processing. The RAM 11C is a volatile or non-volatile storage device that is used as a temporary storage memory (work area) for the various types of processing executed by the CPU 11A. The CPU 11A executes the various control programs stored in advance in the ROM 11B. In this way, the CPU 11A performs overall control of the image forming apparatus 1.

[0017] The sheet transport unit 12 transports the sheets stored in the paper feed cassette 1B along a sheet transport path R11 (see FIG. 1). As shown in FIG. 1, the sheet transport unit 12 includes a pickup roller 12A and multiple transport rollers 12B. The pickup roller 12A picks up the top sheet of the stack of sheets stored in the paper feed cassette 1B and sends the sheet to the sheet transport path R11. The multiple transport rollers 12B are arranged side by side along the sheet transport path R11. Each transport roller 12B transports the sheet along the sheet transport path R11. Each transport roller 12B transports the sheet in a transport direction D11 (see FIG. 1) from the paper feed cassette 1B to the paper output tray 1C.

[0018] The image forming unit 13 forms an image based on image data on a sheet supplied from the sheet conveying unit 12. As shown in Fig. 1, the image forming unit 13 includes line heads 13A to 13D and a head frame 13E.

[0019] 2, each of the line heads 13A to 13D is elongated in a width direction D12 that is perpendicular to a sheet conveyance direction D11 by the sheet conveyance unit 12. Specifically, each of the line heads 13A to 13D has a length in the width direction D12 that corresponds to the width of the largest size sheet that can be accommodated in the sheet cassette 1B. The line heads 13A to 13D are arranged side by side at equal intervals along the conveyance direction D11.

[0020] The line head 13A ejects black ink onto the sheet being transported by the transport unit 14. The line head 13B ejects cyan ink onto the sheet being transported by the transport unit 14. The line head 13C ejects magenta ink onto the sheet being transported by the transport unit 14. The line head 13D ejects yellow ink onto the sheet being transported by the transport unit 14.

[0021] The line heads 13B to 13D have the same configuration as the line head 13A, except that they eject different colors of ink. Only the line head 13A will be described below.

[0022] 2, the line head 13A has three recording heads 13X. Each of the recording heads 13X is elongated in the width direction D12. The three recording heads 13X are arranged in a staggered pattern along the width direction D12.

[0023] Each recording head 13X has a plurality of nozzles 13F (see FIG. 2) on its surface facing the sheet. In each recording head 13X, the plurality of nozzles 13F are arranged along the width direction D12. Specifically, in each recording head 13X, the plurality of nozzles 13F are arranged along the width direction D12 at a density corresponding to the printing resolution of the image forming apparatus 1. For example, the plurality of nozzles 13F are arranged at equal intervals along the width direction D12. In other words, each recording head 13X has a nozzle row formed by the plurality of nozzles 13F arranged at equal intervals along the width direction D12. Note that each recording head 13X may have a plurality of the nozzle rows arranged along the transport direction D11.

[0024] All of the nozzles 13F included in the line head 13A are arranged along the width direction D12. Specifically, the three recording heads 13X included in the line head 13A are arranged in a staggered pattern along the width direction D12 so that all of the nozzles 13F included in the line head 13A are arranged along the width direction D12 at a density corresponding to the printing resolution of the image forming apparatus 1. The line head 13A ejects ink from each of the nozzles 13F. The line head 13A is an example of an ejection unit of the present invention. The multiple nozzles 13F included in the line head 13A are also an example of multiple nozzles of the present invention.

[0025] Each recording head 13X includes a pressure chamber 13G (see FIG. 3), a discharge element 13H (see FIG. 3), and an individual flow path 13J (see FIG. 3) corresponding to each nozzle 13F. The pressure chamber 13G communicates with the nozzle 13F and stores ink. The discharge element 13H discharges ink from the nozzle 13F in response to application of a drive voltage. The discharge element 13H is a piezoelectric element. Specifically, a drive signal including an ON state in which the drive voltage is applied and an OFF state in which the drive voltage is not applied is input to the discharge element 13H. The discharge element 13H discharges ink from the nozzle 13F by changing the pressure in the pressure chamber 13G in response to the input of the drive signal. The individual flow path 13J is an ink flow path provided between the pressure chamber 13G and a common flow path (not shown) shared by multiple nozzles 13F. A plurality of individual flow paths 13J corresponding to the multiple nozzles 13F are connected to the common flow path. The common flow path is connected to an ink supply unit (not shown) that supplies ink to each of the pressure chambers 13G. The ejection elements 13H may be thermoelectric elements or the like.

[0026] The head frame 13E supports the line heads 13A to 13D. The head frame 13E is supported by the housing 1A. The number of line heads provided in the image forming unit 13 may be one or more. Furthermore, the number of recording heads 13X provided in each of the line heads 13A to 13D does not have to be limited to three.

[0027] As shown in FIG. 1, the transport unit 14 is disposed below the line heads 13A to 13D. The transport unit 14 transports a sheet while facing the recording head 13X. For example, the transport unit 14 transports the sheet a predetermined transport distance each time the recording head 13X ejects ink. The transport unit 14 also stops transporting the sheet while the recording head 13X is ejecting ink. As shown in FIG. 1, the transport unit 14 includes a transport belt 14A on which the sheet is placed, a first tension roller 14B, a second tension roller 14C, and a third tension roller 14D that tension the transport belt 14A, and a transport frame 14E that supports these rollers. The gap between the transport belt 14A and the recording head 13X is adjusted so that the gap between the surface of the sheet and the recording head 13X during image formation is a predetermined distance (e.g., 1 mm).

[0028] The first tension roller 14B is driven to rotate by a rotational driving force supplied from a motor (not shown). As a result, the conveyor belt 14A rotates in a direction that allows the sheet to be conveyed in a conveying direction D11 (see FIG. 1). The conveying unit 14 also includes a suction unit (not shown) that sucks air through a number of through-holes formed in the conveyor belt 14A to attract the sheet to the conveyor belt 14A. A pressure roller 14F (see FIG. 1) is provided above the first tension roller 14B to press the sheet against the conveyor belt 14A for conveyance.

[0029] The operation display unit 15 is a user interface of the image forming apparatus 1. The operation display unit 15 includes a display unit and an operation unit. The display unit displays various information in response to control instructions from the control unit 11. For example, the display unit is a flat panel display such as a liquid crystal display. The operation unit inputs various information to the control unit 11 in response to user operations. For example, the operation unit includes operation keys and a touch panel.

[0030] The communication unit 16 is a communication interface that executes wired or wireless data communication with an external communication device such as a personal computer.

[0031] The image reading unit 17 reads the image formed on the sheet by the image forming unit 13 .

[0032] As shown in FIGS. 1 and 4, the image reading unit 17 includes a line sensor 17A and an AFE (analog front end) circuit 17B.

[0033] As shown in FIG. 1, the line sensor 17A is disposed downstream of the image forming unit 13 in the sheet transport path R11 in the transport direction D11. The line sensor 17A is capable of reading an image of one line along the main scanning direction, which is the same direction as the width direction D12 (see FIG. 2), from a sheet passing through the position of the line sensor 17A on the sheet transport path R11. For example, the line sensor 17A is a CIS (contact image sensor). The line sensor 17A includes multiple image sensors arranged side by side in the width direction D12. Each of the image sensors includes a light-emitting unit and a light-receiving unit. The light-emitting unit emits light toward the sheet transported along the sheet transport path R11. The light-receiving unit is configured to receive light emitted from the light-emitting unit and reflected by the sheet, and outputs an analog electrical signal corresponding to the amount of received light. The line sensor 17A outputs analog electrical signals corresponding to one line of an image along the main scanning direction at predetermined intervals in response to a control signal input from the control unit 11.

[0034] The AFE circuit 17B is an electronic circuit that performs predetermined processing on the analog electrical signal output from the line sensor 17A. Specifically, the AFE circuit 17B includes a signal conversion unit that converts the analog electrical signal output from the line sensor 17A into a digital electrical signal (image data). The AFE circuit 17B also includes an image processing unit that performs predetermined image processing, such as shading correction, on the image data output from the signal conversion unit. The AFE circuit 17B outputs the image data output from the image processing unit after the image processing has been performed to the control unit 11.

[0035] Incidentally, an image forming apparatus capable of determining the presence or absence of an abnormal nozzle 13F is known as a related art. Specifically, in the image forming apparatus according to the related art, a line head 13A is used to form a first determination image used to determine the presence or absence of the abnormal nozzle 13F, and a second determination image used to determine the presence or absence of a non-ejection nozzle 13F, which is unable to eject ink, among the abnormal nozzles 13F. Then, the presence or absence of the abnormal nozzle 13F is determined based on the results of reading the formed first determination image. Furthermore, if it is determined that the abnormal nozzle 13F exists, it is determined whether the non-ejection nozzle 13F or the trajectory-bending nozzle 13F, in which the trajectory of ejected ink is curved, is present based on the results of reading the formed second determination image.

[0036] However, in the image forming apparatus according to the related art, it is determined that the nozzle 13F in the deviated trajectory state exists only when it is determined that the nozzle 13F in the abnormal state exists and the nozzle 13F in the non-ejection state does not exist. Therefore, when both the nozzle 13F in the non-ejection state and the nozzle 13F in the deviated trajectory state exist, it cannot be determined that the nozzle 13F in the deviated trajectory state exists.

[0037] In contrast to this, in the image forming apparatus 1 according to the embodiment of the present invention, as will be described below, it is possible to improve the accuracy of determining whether or not there is a nozzle 13F in the curved trajectory state.

[0038] The following describes a method for inspecting nozzles 13F of line head 13A, which is executed in image forming apparatus 1. Note that image forming apparatus 1 also executes a method for inspecting nozzles 13F of other line heads, but since the method is basically the same as the method for inspecting nozzles 13F of line head 13A, a description thereof will be omitted.

[0039] As shown in FIG. 4, the control unit 11 includes a formation processing unit 21, a reading processing unit 22, an acquisition processing unit 23, a determination processing unit 24, and an execution processing unit 25.

[0040] Specifically, a nozzle inspection program for causing the CPU 11A to function as each of the processing units shown in Fig. 4 is stored in advance in the ROM 11B of the control unit 11. The CPU 11A executes the nozzle inspection program to function as each of the processing units described above.

[0041] The nozzle inspection program may be recorded on a computer-readable recording medium such as a CD, DVD, or flash memory, and may be read from the recording medium and stored in a non-volatile storage device provided in the image forming apparatus 1. The nozzle inspection program may also be a program for causing multiple processors to function as the processing units shown in Fig. 4. Some or all of the processing units included in the control unit 11 may be configured with electronic circuits.

[0042] The forming processing unit 21 uses the line head 13A to form on a sheet an acquisition image X10 (see Figure 5) including a first acquisition image X11 (see Figure 5) used to acquire the number of nozzles 13F in the abnormal state and a second acquisition image X12 (see Figure 5) used to acquire the number of nozzles 13F in the non-ejecting state.

[0043] An example of the capture image X10 is shown in Fig. 5. Note that in Fig. 5, the first capture image X11 is hatched.

[0044] The first acquisition image X11 is an image formed using all the nozzles 13F included in the line head 13A. Specifically, as shown in Fig. 5, the first acquisition image X11 is a long, band-shaped solid image extending along the width direction D12. If the line head 13A includes the nozzle 13F in the abnormal state, a white streak appears in the first acquisition image X11 formed on the sheet along the conveyance direction D11.

[0045] The second acquisition image X12 is an image formed using all of the nozzles 13F included in the line head 13A. For example, as shown in Fig. 5, the second acquisition image X12 includes long line images formed by each of the nozzles 13F in the transport direction D11 corresponding to each of the nozzles 13F. If the line head 13A does not include any nozzles 13F in the non-ejecting state, the second acquisition image X12 formed on the sheet includes the same number of line images as the number of nozzles 13F included in the line head 13A.

[0046] The reading processing unit 22 reads the acquisition image X10 formed on the sheet.

[0047] For example, the reading processing unit 22 uses the image reading unit 17 to read the acquisition image X10 formed on the sheet.

[0048] The reading processing unit 22 may read the acquisition image X10 formed on the sheet using a scanner communicably connected to the image forming apparatus 1.

[0049] The acquisition processing unit 23 acquires the number of abnormal nozzles 13F and the number of non-ejecting nozzles 13F based on the reading result by the reading processing unit 22.

[0050] Specifically, the acquisition processing unit 23 detects white streaks along the conveying direction D11 from the scanned image of the first acquisition image X11 formed on the sheet, and acquires the number of detected white streaks as the number of nozzles 13F in the abnormal state.

[0051] The acquisition processing unit 23 also counts the number of line images included in the read image of the second acquisition image X12 formed on the sheet, and acquires the difference between the number of nozzles 13F included in the line head 13A and the count number of the line images as the number of nozzles 13F in the non-ejecting state.

[0052] The determination processing unit 24 determines, based on the results acquired by the acquisition processing unit 23, whether or not there is a nozzle 13F in the abnormal state where the trajectory is bent.

[0053] Specifically, the determination processing unit 24 determines that there are nozzles 13F in a deviated trajectory state when the number of nozzles 13F in the abnormal state is different from the number of nozzles 13F in the non-ejection state.Furthermore, the determination processing unit 24 determines that there are no nozzles 13F in a deviated trajectory state when the number of nozzles 13F in the abnormal state is the same as the number of nozzles 13F in the non-ejection state.

[0054] When the determination processing unit 24 determines that the nozzle 13F in the curved trajectory state exists, the execution processing unit 25 executes a second detection process (an example of the detection process of the present invention) for detecting the nozzle 13F in the curved trajectory state.

[0055] For example, in the second detection process, a detection image used to detect the nozzles 13F in the bent trajectory state is formed on a sheet. Then, each of the nozzles 13F in the bent trajectory state included in the line head 13A is detected based on the result of reading the detection image formed on the sheet by the image reading unit 17. In other words, the position of each of the nozzles 13F in the bent trajectory state in the line head 13A is identified.

[0056] [Nozzle inspection process] 6, the nozzle inspection method of the present invention will be described below, along with an example of the procedure of the nozzle inspection process executed by the control unit 11 in the image forming apparatus 1. Here, steps S11, S12, etc. represent the numbers of the processing procedures (steps) executed by the control unit 11. For example, the nozzle inspection process is executed when an instruction to execute the nozzle inspection process is input by a user's operation on the operation display unit 15.

[0057] <Step S11> First, in step S11, the control section 11 conveys a sheet along the sheet conveying path R11.

[0058] <Step S12> In step S12, the control unit 11 uses the line head 13A to form an acquisition image X10 (see FIG. 5) on the sheet conveyed in the processing of step S11. The processing of step S12 is an example of a forming step of the present invention, and is executed by the formation processing unit 21 of the control unit 11.

[0059] <Step S13> In step S13, the control unit 11 reads the acquisition image X10 formed on the sheet in the processing of step S12 using the image reading unit 17. The processing of step S13 is an example of a reading step of the present invention, and is executed by the reading processing unit 22 of the control unit 11.

[0060] <Step S14> In step S14, the control unit 11 executes a first acquisition process to acquire the number of nozzles 13F in the abnormal state based on the result of the process in step S13.

[0061] Specifically, in the first acquisition process, white streaks along the conveying direction D11 are detected from the scanned image of the first acquisition image X11 formed on the sheet, and the number of detected white streaks is acquired as the number of nozzles 13F in the abnormal state.

[0062] <Step S15> In step S15, the control unit 11 determines whether or not there is any nozzle 13F in the abnormal state.

[0063] Specifically, the control unit 11 determines that there is an abnormal nozzle 13F when the number of abnormal nozzles 13F acquired in the first acquisition process is one or more.

[0064] Here, if the control unit 11 determines that there is a nozzle 13F in the abnormal state (Yes in S15), it shifts the process to step S16. On the other hand, if there is no nozzle 13F in the abnormal state (No in S15), the control unit 11 ends the nozzle inspection process.

[0065] <Step S16> In step S16, the control unit 11 executes a second acquisition process to acquire the number of nozzles 13F in the non-ejecting state based on the result of the process in step S 13. The processes in steps S14 and S16 are an example of an acquisition step of the present invention, and are executed by the acquisition processing unit 23 of the control unit 11.

[0066] Specifically, in the second acquisition process, the number of line images included in the read image of the second acquisition image X12 formed on the sheet is counted, and the difference between the number of nozzles 13F included in the line head 13A and the count number of the line images is acquired as the number of nozzles 13F in the non-ejecting state.

[0067] <Step S17> In step S17, the control unit 11 determines whether or not there is any nozzle 13F in the non-ejecting state.

[0068] Specifically, the control unit 11 determines that there is a nozzle 13F in a non-ejecting state when the number of nozzles 13F in a non-ejecting state acquired in the second acquisition process is one or more.

[0069] Here, if the control unit 11 determines that there is a nozzle 13F in the non-ejecting state (Yes in S17), it shifts the process to step S18. On the other hand, if there is no nozzle 13F in the non-ejecting state (No in S17), the control unit 11 shifts the process to step S20.

[0070] <Step S18> In step S18, the control unit 11 executes a first detection process for detecting the nozzles 13F in the non-ejecting state.

[0071] Specifically, in the first detection process, a line image formation area corresponding to each nozzle 13F is set for the scanned image of the second acquisition image X12 formed on the sheet. The line image formation area is an area of ​​a size that can contain the line image. In addition, in the first detection process, it is determined whether each line image formation area includes the line image. Then, when a line image formation area that does not include the line image is detected, the nozzle 13F corresponding to that line image formation area is determined to be the non-ejecting nozzle 13F.

[0072] <Step S19> In step S19, the control unit 11 executes a first recovery process for recovering the ejection function of the nozzle 13F in the non-ejecting state.

[0073] For example, in the first recovery process, a purge process is executed to forcibly discharge ink from the non-ejecting nozzle 13F, thereby resolving the non-ejecting state caused by clogging of the nozzle 13F.

[0074] In addition, when the first recovery process is executed, the control unit 11 may cause the operation display unit 15 to display a message indicating that the non-ejecting nozzle 13F has been detected and the position of the non-ejecting nozzle 13F.

[0075] <Step S20> In step S20, the control unit 11 determines whether or not there is a nozzle 13F in the curved trajectory state. The process of step S20 is an example of a determination step of the present invention, and is executed by the determination processing unit 24 of the control unit 11.

[0076] Specifically, the control unit 11 determines that there is a nozzle 13F in the curved trajectory state when the number of nozzles 13F in the abnormal state obtained in the first acquisition process is greater than the number of nozzles 13F in the non-ejection state obtained in the second acquisition process.

[0077] Here, if the control unit 11 determines that the nozzle 13F in the trajectory bending state exists (Yes side of S20), the control unit 11 shifts the processing to step S21. On the other hand, if the nozzle 13F in the trajectory bending state does not exist (No side of S20), the control unit 11 ends the nozzle inspection processing.

[0078] <Step S21> In step S21, the control unit 11 executes the second detection process for detecting the nozzle 13F in the curved trajectory. The process of step S21 is executed by the execution processing unit 25 of the control unit 11.

[0079] <Step S22> In step S22, the control unit 11 executes a second recovery process for recovering the ejection function of the nozzle 13F in the curved trajectory state.

[0080] For example, in the second recovery process, a cleaning process is executed to clean the vicinity of the nozzle 13F in the bent trajectory state on the nozzle face, thereby eliminating the bent trajectory state caused by foreign matter adhering to the nozzle 13F.

[0081] In addition, when the second recovery process is executed, the control unit 11 may cause the operation display unit 15 to display a message indicating that the nozzle 13F in the bent trajectory state has been detected and the position of the nozzle 13F in the bent trajectory state.

[0082] In this way, the image forming apparatus 1 acquires the number of nozzles 13F in the abnormal state and the number of nozzles 13F in the non-ejection state, and determines whether or not there are any nozzles 13F in the deviated trajectory state based on these acquired numbers. This makes it possible to determine that there are any nozzles 13F in the deviated trajectory state even when both nozzles 13F in the non-ejection state and nozzles 13F in the deviated trajectory state exist. This makes it possible to improve the accuracy of determining whether or not there are any nozzles 13F in the deviated trajectory state.

[0083] The control unit 11 may include a notification processing unit 26 shown in FIG.

[0084] When the determination processing unit 24 determines that there is a nozzle in the trajectory bending state, the notification processing unit 26 issues a notification to that effect.

[0085] For example, the notification processing unit 26 displays a message on the operation display unit 15 indicating that it has been determined that the nozzle is in the trajectory bending state and recommending execution of the second detection process, thereby urging the user to execute the second detection process.

[0086] [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.

[0087] <Appendix 1> an ejection unit that includes a plurality of nozzles arranged along a width direction perpendicular to the sheet conveying direction and that ejects ink from each of the nozzles; a formation processing unit that uses the ejection unit to form acquisition images on the sheet, the acquisition images including a first acquisition image used to acquire the number of nozzles in an abnormal state and a second acquisition image used to acquire the number of nozzles in a non-ejection state among the abnormal states; a reading processing unit that reads the acquisition images formed on the sheet; an acquisition processing unit that acquires the number of nozzles in the abnormal state and the number of nozzles in the non-ejection state based on the reading result by the reading processing unit; and a judgment processing unit that judges whether or not there are any nozzles in a curved trajectory state among the abnormal states based on the acquisition result by the acquisition processing unit.

[0088] <Appendix 2> An image forming apparatus as described in Appendix 1, further comprising an execution processing unit that executes a detection process to detect the nozzle in the bent trajectory state when the judgment processing unit determines that the nozzle in the bent trajectory state exists.

[0089] <Appendix 3> 2. The image forming apparatus according to claim 1, further comprising: a notification processing unit that, when the determination processing unit determines that the nozzle in the curved trajectory state exists, notifies the user of this.

[0090] <Appendix 4> A nozzle inspection method carried out in an image forming device including a plurality of nozzles arranged along a width direction perpendicular to the sheet conveying direction and equipped with an ejection unit that ejects ink from each of the nozzles, the nozzle inspection method including: a forming step using the ejection unit to form acquisition images on the sheet, the acquisition images including a first acquisition image used to acquire the number of nozzles in an abnormal state and a second acquisition image used to acquire the number of nozzles in a non-ejection state among the abnormal states; a reading step to read the acquisition images formed on the sheet; an acquisition step to acquire the number of nozzles in the abnormal state and the number of nozzles in the non-ejection state based on the reading result from the reading step; and a determination step to determine whether or not there are any nozzles in a bent trajectory state among the abnormal states based on the acquisition result from the acquisition step. [Explanation of symbols]

[0091] 1. Image forming device 11 Control section 12 Sheet transport section 13 Image forming unit 13A Line Head 13F Nozzle 14 Transport unit 15 Operation display section 16 Communications Department 17 Image reading unit 21 Formation processing section 22 Reading processing section 23 Acquisition processing unit 24 Judgment processing unit 25 Execution processing section 26 Notification processing section

Claims

1. an ejection unit including a plurality of nozzles arranged along a width direction perpendicular to a sheet conveyance direction, and configured to eject ink from each of the nozzles; a forming processing unit that uses the ejection unit to form, on the sheet, acquisition images including a first acquisition image used to acquire the number of the nozzles in an abnormal state and a second acquisition image used to acquire the number of the nozzles in a non-ejection state among the abnormal states; a reading processing unit that reads the acquisition image formed on the sheet; an acquisition processing unit that acquires the number of the abnormal nozzles and the number of the non-ejection nozzles based on the reading result by the reading processing unit; a determination processing unit that determines whether or not the nozzle is in a curved trajectory state, which is one of the abnormal states, based on the results acquired by the acquisition processing unit; and An image forming apparatus comprising:

2. an execution processing unit that, when it is determined by the determination processing unit that the nozzle in the trajectory bending state exists, executes a detection process to detect the nozzle in the trajectory bending state; The image forming apparatus according to claim 1 .

3. a notification processing unit that, when the determination processing unit determines that the nozzle in the trajectory bending state exists, notifies the user of that fact; The image forming apparatus according to claim 1 .

4. A nozzle inspection method executed in an image forming apparatus including a plurality of nozzles arranged along a width direction perpendicular to a sheet conveyance direction, the image forming apparatus including an ejection unit that ejects ink from each of the nozzles, the method comprising: a forming step of forming, on the sheet, acquisition images including a first acquisition image used to acquire the number of the nozzles in an abnormal state and a second acquisition image used to acquire the number of the nozzles in a non-ejection state among the abnormal states, using the ejection unit; a reading step of reading the acquisition image formed on the sheet; an acquisition step of acquiring the number of the abnormal nozzles and the number of the non-ejection nozzles based on the reading result of the reading step; a determination step of determining whether or not the nozzle is in a curved trajectory state among the abnormal states based on the results obtained by the obtaining step; A nozzle inspection method comprising:

Images