JP2012091526A - Nozzle inspection apparatus, nozzle inspection method, and inspection program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nozzle inspection apparatus that can shorten a time for inspecting nozzles according to a printing mode related to a printing job to be printed so as to shorten a time until images are printed, and to provide a nozzle inspection method and inspection program.SOLUTION: The nozzle inspection apparatus acquires information on a printing mode associated with a printing job from a plurality of stored inspection modes, selects the inspection mode based on the acquired information and performs the nozzle inspection. Accordingly, the time for inspecting the nozzles can be shortened in accordance with the printing modes without unnecessarily lengthening the time without inspecting the nozzles including the uniformly same processing regardless of the printing modes.

Description

  The present invention relates to a nozzle inspection technique for inspecting whether or not the recording liquid is ejected from a plurality of nozzles for ejecting a recording liquid and printing a print target on a medium.

  In an inkjet recording apparatus that discharges recording liquid from a plurality of nozzles provided in a print head and prints an image or the like as a printing object on recording paper as a medium, an image to be printed unless the recording liquid is discharged from the nozzle Will not be printed correctly. Therefore, it has been conventionally performed to inspect whether or not the recording liquid is ejected from the nozzles before printing the image, and to perform a predetermined cleaning treatment for the nozzles from which the recording liquid is not ejected. For this reason, if there is a nozzle from which the recording liquid is not ejected as a result of the inspection, the nozzle cleaning process is performed, and therefore it may take a considerable time until the image is actually printed.

  Thus, for example, Patent Document 1 discloses a technique for shortening the time until an image is printed. In Patent Document 1, printing is performed without performing a cleaning process if the number of nozzles that do not eject recording liquid is within the allowable number set according to the image quality of the image to be printed. As a result, depending on the image quality of the image to be printed, printing is performed without performing a cleaning procedure, and the time until printing can be shortened.

JP 2003-165231 A

  By the way, in the nozzle inspection, the presence / absence of discharge of the recording liquid is normally inspected in order of one nozzle. Also in Patent Document 1, nozzle inspection is performed at intervals of four nozzles, but nozzle inspection processing is basically performed one by one. Therefore, when the number of nozzles provided in the print head is large, a lot of inspection time is required. For this reason, the technique disclosed in Patent Document 1 shortens the time required for printing by the time required for the cleaning treatment according to the image quality of the print target image, but does not reduce the time required for the nozzle inspection. There wasn't. Therefore, when the number of nozzles provided in the print head is large, a long nozzle inspection time is required, and there is a problem that a long time is still required until an image is actually printed.

  The present invention has been made in view of such problems, and in order to shorten the time until an image is printed, the nozzle inspection time is shortened according to the print mode associated with the print job to be printed. It is an object to provide a nozzle inspection device, a nozzle inspection method, and an inspection program that can be performed.

  In order to solve the above-described problems, the present invention inspects whether or not the recording liquid is ejected from the plurality of nozzles for ejecting the recording liquid according to the printing mode and printing the print target on the medium. A nozzle inspection device, wherein an inspection mode storage unit that stores a plurality of inspection modes that define inspection processing contents, and a print job that is a target of printing on the medium, A print mode information acquisition unit that acquires information about the print mode associated with the print job, and an inspection mode that selects one inspection mode from the plurality of stored inspection modes based on the acquired information about the print mode The gist includes a selection unit and a nozzle inspection unit that inspects whether or not the recording liquid is discharged in accordance with the selected one inspection mode.

  According to this configuration, an inspection mode is selected from a plurality of stored inspection modes based on information about a print mode accompanying a print job to be printed, and a nozzle inspection is performed. For example, in the case of a print job for printing an image having image data with a relatively low resolution, such as character data such as document data or text data, there are several pixels (also referred to as dot missing) from which no recording liquid is ejected. However, this may not be a problem for printed images. On the other hand, in the case of a print job that prints an image having image data with a relatively high resolution, such as image data such as a photographic image, even if there are a small number of missing dots, there is a problem with the printed image. There is. Therefore, for the inspection of whether or not the recording liquid is ejected from the nozzle, from the plurality of inspection modes that define different inspection contents, the most suitable inspection processing content according to the information about the print mode (for example, print resolution) attached to the print job The selected inspection mode is selected. As a result, since the same processing contents are not uniformly inspected regardless of the print mode, the nozzle inspection time can be shortened according to the print mode without unnecessarily lengthening the nozzle inspection time. . As a result, the time until the image is printed can be shortened.

  Here, the inspection mode storage unit may store at least one of the plurality of inspection modes as an inspection mode in which the recording liquid is simultaneously ejected from a plurality of inspection target nozzles.

  In this way, in the nozzle inspection, when this stored inspection mode is selected based on the information about the printing mode, the recording liquid is simultaneously ejected from the plurality of inspection target nozzles, so that one nozzle is used. In the inspection process, the recording liquid is simultaneously ejected from a plurality of nozzles to be inspected to inspect whether or not the recording liquid is ejected. Accordingly, since the value obtained by dividing the number of all nozzles to be inspected by the number of nozzles to be inspected in one nozzle inspection process is the largest number of nozzle inspection processes, the nozzle inspection process is performed one by one. The inspection time can be shortened compared to the case where it is performed. As a result, it is possible to shorten the time until the image is printed.

  Further, when the information regarding the print mode acquired by the print mode information acquisition unit is information regarding a print mode for printing a text printed matter, the inspection mode selection unit simultaneously receives the plurality of inspection target nozzles from the plurality of inspection target nozzles. It is also possible to select an inspection mode in which the recording liquid is ejected for inspection.

  When the print mode is a print mode for printing a text printed matter, a predetermined number of consecutive dot omissions may be allowed. Therefore, when the information on the print mode is information on the print mode for printing a text printed matter, the nozzle test is performed by simultaneously ejecting the recording liquid from a plurality of nozzles to be inspected according to the allowable number of consecutive missing dots. It is preferable to select an inspection mode for performing the above. In this way, since the inspection time can be shortened compared with the case where the nozzle inspection process is performed one by one, it is possible to shorten the time until the image is printed.

  Furthermore, it has a plurality of cleaning treatments for cleaning the nozzles that do not discharge the recording liquid with different recovery processes, and enters the selected inspection mode based on the inspection result of the nozzle inspection performed by the nozzle inspection unit. A cleaning treatment selection unit that selects a corresponding cleaning treatment from the plurality of cleaning treatments may be provided.

  In this way, since a cleaning procedure corresponding to the inspection mode is selected from a plurality of cleaning procedures, a cleaning procedure suitable for setting the number of missing dots to be equal to or less than the allowable number of missing dots according to the inspection mode is performed. Can do. Therefore, since unnecessary cleaning treatment is not performed, the time required for cleaning can be shortened, and as a result, the time until printing can be shortened.

  In order to solve the above-described problem, the present invention provides a nozzle inspection apparatus that inspects whether or not the recording liquid is ejected from the plurality of nozzles with respect to the plurality of nozzles that eject the recording liquid and print a print target on the medium. A first inspection process is performed in which a plurality of inspection target nozzles are selected from the plurality of nozzles, and the recording liquid is simultaneously discharged from the selected plurality of inspection target nozzles to inspect whether or not the recording liquid is discharged. And a nozzle inspection unit that inspects whether or not the recording liquid is discharged in accordance with the first inspection mode.

  According to this configuration, in the nozzle inspection, the recording liquid is simultaneously ejected and inspected from the plurality of inspection target nozzles according to the stored first inspection mode. That is, the recording liquid is ejected simultaneously from a plurality of nozzles to be inspected in one nozzle inspection process, and the presence or absence of the recording liquid is inspected. Accordingly, since the value obtained by dividing the number of all nozzles to be inspected by the number of nozzles to be inspected in one nozzle inspection process is the largest number of nozzle inspection processes, the nozzle inspection process is performed one by one. The inspection time can be shortened compared to the case where it is performed. As a result, it is possible to shorten the time until the image is printed.

  Here, the inspection mode storage unit further stores an inspection process different from the first inspection mode as a second inspection mode, and the nozzle inspection unit is based on a nozzle inspection result in the first inspection mode. Then, the presence or absence of ejection of the recording liquid may be inspected according to the second inspection mode.

  In this case, when the inspection result in the first inspection mode indicates that the number of consecutive dot omissions exceeds the allowable number according to the print mode, the second inspection mode is different from the first inspection mode. The nozzle inspection will be performed. In such a case, for a nozzle that has a low probability that a non-ejection state in which no recording liquid is ejected is continuously generated, the first inspection is performed by preparing two inspection modes in this way and performing the nozzle inspection. It can be expected that there are many cases where the nozzle inspection results in the mode satisfy the acceptable quality of missing dots. Therefore, in such a case, it can be expected that the time until the image is printed is considerably shortened by performing the nozzle inspection by dividing the inspection mode into two.

  Further, the second inspection mode may be an inspection mode in which the recording liquid is ejected and the presence or absence of the recording liquid is inspected by each of the plurality of nozzles.

  In this way, when the inspection result of the nozzle inspection in the first inspection mode is, for example, an inspection result that the number of consecutive dot omissions exceeds the allowable number according to the printing mode, the inspection for the presence or absence of ejection for each nozzle is further performed. By performing the above, it is possible to specify the details of the number of consecutive missing dots and the nozzles causing missing dots. As a result, the occurrence of missing dots can be inspected in more detail.

  Furthermore, it has a plurality of cleaning treatments for cleaning the nozzles that do not discharge the recording liquid with different recovery processes, and enters the selected inspection mode based on the inspection result of the nozzle inspection performed by the nozzle inspection unit. A cleaning treatment selection unit that selects a corresponding cleaning treatment from the plurality of cleaning treatments may be provided.

  In this way, since a cleaning procedure corresponding to the inspection mode is selected from a plurality of cleaning procedures, a cleaning procedure suitable for setting the number of missing dots to be equal to or less than the allowable number of missing dots according to the inspection mode is performed. Can do. Therefore, since unnecessary cleaning treatment is not performed, the time required for cleaning can be shortened, and as a result, the time until printing can be shortened.

  Here, the nozzle inspection unit applies a voltage between the recording liquid and a receiving area where the recording liquid lands after being ejected from the nozzle, and based on a change in the voltage generated as the recording liquid is ejected. Then, the presence or absence of the recording liquid ejection may be inspected.

  In this way, since a voltage change corresponding to the number of inspection target nozzles to which the recording liquid is simultaneously discharged occurs, the number of inspection target nozzles to which the recording liquid is simultaneously discharged can be changed without changing the special inspection apparatus. By comparing with the voltage change, it is possible to inspect whether or not the recording liquid is discharged.

  The present invention can also be understood as an inspection method. That is, a nozzle inspection method for inspecting whether or not the recording liquid is ejected from the plurality of nozzles for ejecting the recording liquid according to a printing mode and printing a print target on the medium, An inspection mode storage step for storing a plurality of inspection modes in which inspection processing contents are determined for the inspection of whether or not liquid is discharged, and the print mode associated with the print job from a print job to be printed on the medium A print mode information acquisition step for acquiring information; an inspection mode selection step for selecting one inspection mode from the plurality of stored inspection modes based on the acquired information on the print mode; And a nozzle inspection step for inspecting whether or not the recording liquid is discharged according to one inspection mode.

  Alternatively, a nozzle inspection method for inspecting whether or not the recording liquid is ejected from the plurality of nozzles for a plurality of nozzles that eject the recording liquid and print a print target on the medium, An inspection mode storage step of selecting an inspection target nozzle and storing, as a first inspection mode, an inspection process in which the recording liquid is simultaneously discharged from the selected plurality of inspection target nozzles to inspect whether or not the recording liquid is discharged; And a nozzle inspection step for inspecting whether or not the recording liquid is discharged in accordance with the first inspection mode.

  According to the nozzle inspection method of the present invention, the same operational effects as those of the nozzle inspection apparatus of the present invention described above can be obtained. This nozzle inspection method may be executed in a nozzle inspection apparatus having the above-described aspect, or may be executed in a nozzle inspection apparatus having another aspect.

  Furthermore, this invention is good also as a program for making a computer perform each procedure of the nozzle inspection method mentioned above.

  By executing this program on a predetermined operation system, the above-described nozzle inspection method is executed, and the same operational effects as the above-described nozzle inspection apparatus of the present invention can be obtained. This program may be recorded on a computer-readable recording medium, or may be transferred to the computer via a transmission medium such as the Internet.

1 is a schematic structural diagram of an inkjet printer according to an embodiment of the present invention. The schematic diagram which shows the apparatus structure of the nozzle test | inspection apparatus of this invention. Explanatory drawing of the piezoelectric element drive method which discharges an ink drop from a test object nozzle. (A) is a timing chart showing the case of inspecting one nozzle at a time. (B) is a timing chart showing a case where three nozzles are inspected. The flowchart which shows the nozzle test | inspection process of this embodiment. The flowchart explaining the process of the inspection mode 1. FIG. 10 is a flowchart for explaining processing in inspection mode 2; 10 is a flowchart for explaining processing in inspection mode 3; 10 is a flowchart for explaining processing in inspection mode 4; Explanatory drawing explaining the other test example about a nozzle test | inspection method.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a schematic structure of an ink jet printer 10 in which the nozzle inspection apparatus of the present invention is incorporated. The inkjet printer 10 includes a carriage 20 mounted with ink cartridges 11 to 14 that store inks of Y (yellow), M (magenta), C (cyan), and K (black) as recording liquids. When the print medium 25 moves in the vertical direction of the drawing, ink droplets are ejected from the print head 30 provided on the lower side of the carriage 20 to print a predetermined image or the like on the print medium 25. It is.

  The carriage 20 is fixed to the carriage belt 41, and moves along the guide 21 fixed to the frame 17 as the carriage belt 41 is driven by the carriage motor 40. The print medium 25 is moved in the vertical direction of the drawing by a paper feed roller (not shown) driven by a drive motor 26 fixed to the frame 17. At this time, a predetermined ink droplet corresponding to the print image is ejected from a plurality of nozzles provided in the print head for ejecting each color ink, whereby the image is printed correctly. Therefore, a print image cannot be printed correctly unless ink droplets are ejected from each nozzle.

  For this reason, in the inkjet printer 10, the inspection timing to be inspected at a predetermined time such as when the power is turned on, before the start of the print job for printing the print object, in the middle of the print job, or at the end of the print job arrives. In this case, nozzle inspection is performed on the plurality of nozzles provided in the print head to inspect whether ink droplets are ejected from the nozzles. Nozzle inspection is performed based on the inspection processing content determined by a predetermined inspection mode, which will be described later, by moving the carriage 20 to the position of an inspection box 70 provided in the ink jet printer 10, and ejecting ink droplets from each nozzle. Check for the presence or absence of. As a result of the inspection, if there is a nozzle from which ink droplets are not ejected, the carriage 20 is moved to the position of the cleaning box 18 provided in the inkjet printer 10 and a predetermined cleaning process is performed to clean the nozzle.

  The main control for these operations is performed by a main control board (simply a main board) 50 attached to the frame 17 and a sub-control board (simply a sub board) 60 attached to the end face of the carriage 20. These substrates are connected by a flexible substrate 45 so that data can be exchanged between the substrates.

  The main board 50 has a CPU 51 for controlling various operations of the ink jet printer 10, a ROM 52 for recording a program related to these operations, and a RAM 53 for temporarily storing and reading data necessary for the operation. An interface (I / F) for exchanging data between the flash memory 54 capable of writing and erasing data and the sub board 60 and exchanging information with an external device such as a personal computer (PC) 90 of the user. 55. A processing routine program for nozzle inspection described later is stored in the ROM 52. The RAM 53 has a buffer area for print data, and stores print job data output from the PC 90 via the I / F 55 in this area.

  In the PC 90, an image or the like as a print object and a print mode are set by a printer driver, and the print data is transmitted to the printer as data of a print job in which data indicating the print mode is attached to data such as an image. The print mode is information for designating what kind of printing method an image or the like should be printed by the printer. Here, the printing method is, for example, the type of printing paper, the type of data to be printed (image or text), printing resolution, number of print gradations, color printing or monochrome printing, and the type of ink used for printing. , Including bidirectional printing or unidirectional printing, and the like, shows a method when the printer performs printing. When printing is performed only by the inkjet printer 10 without using the PC 90, a function corresponding to a printer driver is provided in the inkjet printer 10, and the function corresponding to the provided printer driver is used as a print object. The image and the print mode are set, and the image data and the information data indicating the print mode are generated as print job data (also simply referred to as “print data”).

  On the other hand, the sub-board 60 is provided with an ASIC 61 in which a logic circuit for executing a predetermined operation related to nozzle inspection is configured. Therefore, when the CPU 51 reads the nozzle inspection program recorded in the ROM 52 and exchanges various signal data with the ASIC 61, the CPU 51 and the ASIC 61 execute a predetermined operation to perform the nozzle inspection.

  Next, the configuration of the nozzle inspection apparatus will be specifically described with reference to FIG. FIG. 2 is a schematic diagram showing an apparatus configuration for determining whether ink is ejected by applying pressure to the ink so as to eject ink from each of a plurality of nozzles provided in the print head using charged ink droplets. . When the carriage 20 moves to a predetermined position with respect to the inspection box 70, the ink supplied from the ink cartridges 11 to 14 to the print head through a supply path (not shown) is ejected from the print head 30 as ink droplets 39.

  Each of the plurality of nozzles provided in the print head 30 is formed with a mechanism for generating pressure for ejecting ink for each nozzle as shown in the lower circle of FIG. That is, when a voltage is applied to the piezoelectric element 32, the piezoelectric element 32 is deformed to push down the member 33 in the direction of the arrow (the lower side in the drawing), and pressurizes the ink 38 supplied from, for example, the ink cartridge 11. . As a result, ink is ejected as ink droplets 39 from the nozzles 35 provided on the nozzle plate 34. Therefore, by applying a voltage to the piezoelectric element 32 corresponding to the nozzle to be inspected, it is possible to inspect whether or not an ink droplet has been ejected from that nozzle. A voltage for deforming the piezoelectric element 32 is output from the driver substrate 31 as a drive signal for the piezoelectric element 32. The driver board 31 is provided in the carriage 20 in the vicinity of the print head 30, is connected to the sub board 60 by a connection member (not shown), and operates in response to an output signal from the ASIC 61.

  Here, how the piezoelectric element corresponding to the nozzle to be inspected is driven will be described with reference to FIG. FIG. 3 is an explanatory diagram for explaining a driving method of a piezoelectric element that is driven to eject ink droplets from the inspection target nozzle. In this embodiment, the print head 30 is provided with nozzle rows 35Y, 35M, 35C, and 35K corresponding to Y, M, C, and K, and each nozzle row has 180 nozzles from n = 1 to 180. Nozzle is formed. Thus, in the present embodiment, a total of 720 nozzles to be inspected are formed in the print head 30. Then, in order to eject ink droplets from the nozzles to be inspected, for each YMCK nozzle row, a drive signal DRVn (for driving the piezoelectric elements to be deformed with respect to the piezoelectric elements 32 (see FIG. 2) corresponding to the nozzles to be inspected). n = 1 to 180) is output from the driver board 31.

  The drive signal DRVn is generated as follows. In the main board 50, a total of four pulse signals of Pv, P1, P2, and P3 are sent in a section for printing an image corresponding to one pixel (also called a segment when the carriage 20 crosses one pixel interval). The original signal ODRV in which the unit signal (the blowing portion in FIG. 3) is repeatedly generated and the print signal PRTn for specifying the nozzle that ejects ink droplets during printing are generated.

  The original signal ODRV includes a pulse signal Pv for causing the piezoelectric element to vibrate slightly so that the ink does not solidify in the nozzle, and pulse signals P1, P2 for ejecting one ink drop from the nozzle, respectively. P3. A small size dot is formed on the print medium only by the pulse signal P1, a medium size dot is formed by the pulse signals P1 and P2, and a large size dot is formed by the pulse signals P1, P2 and P3, respectively.

  The print signal PRTn (n = 1 to 180) outputs a drive signal DRVn for driving the piezoelectric element to the piezoelectric element corresponding to the nozzle to which ink droplets should be ejected among the 180 nozzles for each nozzle row of YMCK. Signal. Therefore, the print signal PRTn selects a nozzle to be ejected ink and print data to be ejected (the presence / absence of a dot and its gradation value) based on the print image, and selectively supplies a drive signal to the nozzle. This signal is a nozzle selection signal that selectively supplies a drive signal to the nozzles to which ink should be ejected for inspection during ejection inspection. Therefore, hereinafter, a print signal is also referred to as a nozzle selection signal in nozzle inspection.

  These signals are output to the mask circuit provided on the driver board via the ASIC 61 as described above. The mask circuit is configured so that a signal while the print signal PRTn is output is output to the piezoelectric element among the original signals. That is, the mask circuit is configured to output the pulse signal selected by the print signal among the pulse signals Pv, P1, P2, and P3 to the piezoelectric element corresponding to the selected nozzle to be inspected. Thus, the drive signal DRVn is generated.

  In the nozzle inspection, the drive signal DRVn generated by the mask circuit in this way is output to the inspection target nozzle selected by the print signal, that is, the nozzle selection signal PRTn, for 180 nozzles in one nozzle row. Repeated sequentially. By applying this procedure to all the nozzle rows of YMCK, the corresponding piezoelectric elements are sequentially driven for all the nozzles provided in the print head, and the ejection inspection is performed.

  Returning to FIG. 2, the ejected ink droplets 39 land on the electrode member 71 provided in the inspection box 70. The electrode member 71 is made of a metal material such as a mesh-like SUS plate and serves as a landing receiving area for the ink droplets 39. The landed ink droplet 39 then passes through this electrode member and is absorbed by the ink absorber 72 formed of sponge-like resin or the like. Thus, the electrode member 71 is configured not to deposit ink. The electrode member 71 is electrically connected to the frame 17 by a connection member 66.

  A voltage generation circuit 62 is provided on the sub-board 60 provided with the ASIC 61. The ASIC 61 operates a voltage generation circuit 62 in which one end of the circuit is connected (grounded) to the frame 17 during nozzle inspection, generates a predetermined voltage with respect to the frame 17, and then connects through the resistor 64 having a predetermined resistance value. A predetermined voltage is applied from the member 65 to the print head 30. Of course, the portion to which the voltage is applied in the print head 30 is a portion (for example, the nozzle plate 34) that is electrically connected to the ink 38.

  As described above, when the print head 30 and the electrode member 71 are used as two measurement terminals and a predetermined voltage is applied between the measurement terminals, when ink droplets are ejected from the nozzles, the charged ink The voltage between the measurement terminals changes due to the flying of the droplet. Accordingly, by measuring the voltage value between the measurement terminals, it is possible to detect the presence of ink droplet ejection if there is a voltage change, and the absence of ink droplet ejection if there is no voltage change. The nozzle inspection apparatus in the present embodiment is configured as described above.

  The CPU 51 controls the ROM 52, the RAM 53, and the ASIC 61 to execute the nozzle inspection processes shown in the flowcharts of FIGS. 5 to 9, the inspection mode storage unit 51a, the image quality acquisition unit 51b, the inspection mode selection unit 51c, It functions as a nozzle inspection unit 51d and a cleaning treatment determination unit 51e. And the nozzle test | inspection apparatus which has the structure mentioned above is operated, and the presence or absence of the discharge of an ink drop is test | inspected about each nozzle. Each unit mainly manages the following processing.

  The inspection mode storage unit 51a stores inspection modes that define different contents of inspection processing. In the present embodiment, the inspection mode storage unit 51a corresponds to the ROM 52, and stores three inspection modes described later. Each inspection mode defines the contents of inspection processing based on the print mode, and is associated with each print mode and stored in the ROM 52 in advance. Of course, the contents of the inspection process may be determined according to characteristic values representative of the printing performance of the inkjet printer 10 such as the number of nozzles provided in the print head and the segment time described above, in addition to the print mode. . Alternatively, the CPU 51 receives the data corresponding to the inspection mode desired by the user output from the PC 90 or the like via the I / F 55 and stores the data in the RAM 53 or the flash memory 54 to determine the inspection processing content. Also good.

  The print mode information acquisition unit 51b acquires information related to the print mode from the print data. The CPU 51 obtains information related to the print mode by reading data associated with the print mode from the print data output from the PC 90 and stored in the RAM 53.

  The inspection mode selection unit 51c selects an inspection mode corresponding to the print mode from the three inspection modes stored in the inspection mode storage unit based on the information regarding the print mode acquired by the print mode information acquisition unit. The CPU 51 compares the information about the print mode acquired from the print data stored in the RAM 53 with the print mode associated with the plurality of inspection modes stored in the ROM 52, thereby comparing the plurality of inspection modes. To select one or two inspection modes.

  The nozzle inspection unit 51d performs nozzle inspection according to the selected inspection mode, and inspects whether ink is ejected from the nozzles. The CPU 51 drives the piezoelectric element based on the contents of the inspection process set in the selected inspection mode while exchanging data with the ASIC 61. Then, a change in voltage between the print head 30 and the electrode member 71 is measured. As a result of the measurement, if there is a change in voltage when the piezoelectric element is driven, ink is ejected from the nozzle to be inspected. When there is no change, the absence of ink ejection is detected from the nozzle to be inspected.

  Further, when two inspection modes are selected, the nozzle inspection unit 51d also determines whether or not to perform the nozzle inspection in the second inspection mode according to the inspection result of the nozzle inspection in the first inspection mode.

  Further, the cleaning treatment determination unit 51e determines whether or not to perform the cleaning treatment according to the inspection mode performed by the nozzle inspection unit 51d based on the nozzle inspection result performed by the nozzle inspection unit 51d. When the cleaning treatment method corresponding to the inspection mode is stored in the ROM 52 in advance, and the CPU 51 determines to perform the cleaning treatment based on the nozzle inspection result, the treatment method corresponding to the inspection mode is read from the ROM 52 and the cleaning treatment is performed. is there.

  Next, before describing the nozzle inspection process performed by the function of each section, the nozzle driving method performed in the nozzle inspection process and the state of voltage change caused by the presence or absence of ink ejection from the nozzle This will be described with reference to FIG.

  FIG. 4A is a timing chart showing a case where nozzles are driven one by one and whether or not ink droplets are ejected is detected for each nozzle. As shown in the figure, when the original signal ODRV and the nozzle selection signals PRT1 and PRT2 are output to the mask circuit, the piezoelectric element drive signal DRV1 for the nozzle n = 1 and the piezoelectric element drive for the nozzle n = 2. Signal DRV2 is output.

  As shown in the figure, the 8-segment unit signal is output (ON) to the nozzle n = 1 by the nozzle selection signals PRT1 and PRT2, and the next 8-segment unit signal is not output (OFF). An 8-segment unit signal is output (ON) for nozzle n = 2, and the next 8-segment unit signal is not output (OFF). Thereafter, although not shown, nozzles n = 3, 4,... Are sequentially selected by the nozzle selection signal, and the piezoelectric elements corresponding to the selected nozzles are sequentially driven. In this embodiment, the unit signal between 8 segments is output in this way, and the “ON” and “OFF” states in which the unit signal between 8 segments is not output are repeated, and the piezoelectric element corresponding to the inspection nozzle is driven. The horizontal axis represents the time axis T.

  Next, the voltage change between the measurement terminals will be described. First, when the nozzle selection signal PRT1 outputs a unit signal between 8 segments for the nozzle n = 1 from the start of inspection (T = 0) to the time t1, when an ink droplet is ejected, a predetermined voltage applied between the measurement terminals is output. As shown in the figure, the voltage Ve gradually decreases in accordance with the number of ejections, exceeds the threshold value TH1, and decreases by ΔV1. Thereafter, since the nozzle n = 1 is not driven for 8 segments from time t1 to time t2, ink droplets are not ejected. As a result, the voltage between the measurement terminals gradually increases and then recovers to the value Ve. Here, the threshold value TH1 is a threshold value used when determining whether or not an ink droplet is ejected from a nozzle. In this embodiment, when the decrease value of the voltage between the measurement terminals exceeds the threshold value TH1, it is determined that the voltage has decreased. The voltage between the measurement terminals actually measured may vary within a considerable range due to electric field noise from the outside of the printer. Therefore, a threshold value is provided in order to accurately detect a voltage change due to ink droplet ejection.

  Next, from time t2 to time t3 by the nozzle selection signal PRT2, a unit signal between 8 segments is output (ON) for nozzle n = 2, and when ink droplets are ejected, the measurement terminal voltage Ve matches the number of ejections. Then, the voltage gradually decreases again and decreases by ΔV1 as in the case of nozzle n = 1. Thereafter, since the nozzle n = 2 is not driven for 8 segments from time t3 to t4 (OFF), ink droplets are not ejected, and as a result, the voltage between the measurement terminals gradually increases and then recovers to the value Ve. Such a voltage change is repeatedly generated between the measurement terminals every time an ink droplet is ejected. Of course, when no ink droplet is ejected, no voltage change occurs, so the voltage Ve does not change as shown by the horizontal broken line in FIG.

  Therefore, the voltage value between the measurement terminals at the start and end of driving of the piezoelectric element is measured, and if the voltage change during this period is greater than or equal to the threshold value TH1, ink droplets are ejected. If the voltage change is not greater than the threshold value, ink ejection is performed. It can be detected that there is not.

  On the other hand, FIG. 4B is a timing chart showing a case where three nozzles are driven and three ink droplets are detected at the same time. As shown in the figure, nozzle selection signals PRT1 to PRT3 are simultaneously output to the mask circuit, and piezoelectric element drive signals DRV1 to DRV3 corresponding to nozzles n = 1 to 3 are simultaneously output for 8 segments. Thereafter, after the elapse of 8 segments, nozzle selection signals PRT4 to PRT6 are simultaneously output to the mask circuit, and piezoelectric element drive signals DRV4 to DRV6 corresponding to nozzles n = 4 to 6 are simultaneously output for 8 segments. Thereafter, three nozzles are sequentially selected simultaneously such as nozzles n = 7-9, 10-12,... And corresponding piezoelectric elements are driven.

  At this time, from the inspection start (T = 0) to the time t1, an 8-segment unit signal is output to the nozzles n = 1 to 3 according to the nozzle selection signals PRT1 to PRT3, and at least one nozzle among the three nozzles ( In the figure, when ink droplets are ejected from nozzle n = 1), the voltage Ve between the measurement terminals gradually decreases according to the number of ejections as shown in the figure, and decreases by at least ΔV1. Thereafter, since no piezoelectric element is driven for 8 segments from time t1 to time t2, ink droplets are not ejected. As a result, the voltage between the measurement terminals increases and recovers to the value Ve.

  Next, when an 8-segment unit signal is output for nozzles n = 4-6 from time t2 to time t3 by nozzle selection signals PRT4-6, no ink droplets are ejected from all three nozzles. In this case, since the voltage change due to the flying of the charged ink droplet does not occur, the voltage Ve between the measurement terminals does not change. Therefore, the voltage Ve does not change as shown in the lower side of FIG.

  Therefore, the voltage value between the measurement terminals at the start and end of driving of the piezoelectric element, that is, at the start and end of output of the drive signal of the piezoelectric element is measured. It is possible to detect that ink droplets are ejected from at least one of the nozzles, and ink is not ejected from three consecutive nozzles if the voltage change does not exceed the threshold TH1. That is, it is possible to determine whether or not there is a missing dot continuously for three dots. Thus, the threshold value TH1 is set so that the voltage change exceeds the threshold value TH1 if ink droplets are ejected from at least one of a plurality (three in this embodiment) of nozzles that simultaneously eject ink. Value. Therefore, when the voltage change does not exceed the threshold value TH1, it can be determined that ink droplets are not ejected from all of the plurality of nozzles. In other words, if the number of the plurality of nozzles is set to a predetermined number, it is possible to determine whether or not there is a predetermined number of nozzles that do not eject ink continuously.

  On the other hand, the threshold value TH2 may be set so as not to exceed the threshold value when one of the three nozzles does not eject ink droplets. The change of the voltage Ve in this case is shown in the lower part of FIG. As shown in the figure, when ink droplets are ejected from all three nozzles, the voltage Ve drops as shown by a broken line and decreases by the voltage ΔV2. Therefore, if a threshold value TH2 that is a predetermined amount smaller than this voltage ΔV2 is set, among the nozzles of a predetermined number of nozzles (three in this embodiment), there are nozzles that do not eject one or more ink droplets. In this case, since the threshold value TH2 is not exceeded, it can be determined whether or not there is at least one nozzle that does not eject ink droplets out of a predetermined number of nozzles. Therefore, in this case, the maximum number is detected for a number in which a predetermined number of consecutive non-ejection nozzles may exist.

  The present embodiment uses the voltage change between the print head 30 and the electrode member 71 described above, and basically drives a piezoelectric element corresponding to a predetermined number of nozzles according to the image quality of the print image, The nozzle inspection time is to be shortened by detecting whether or not there is a missing dot continuously for a predetermined number of times.

  Here, the inspection timing of the nozzle inspection will be described. The ink jet printer 10 stores a condition that is an inspection timing at which nozzle inspection should be performed. Based on this condition, the ink jet printer 10 determines whether or not the inspection timing has arrived, and determines that the inspection timing has arrived. Perform an inspection. The stored inspection timing conditions include a predetermined time since the previous inspection, a predetermined number of ink droplet ejections, a predetermined number of passes (the number of times the carriage has moved relative to the print medium for the printing operation), a predetermined number The number of printed pages. In addition, when the time when the inspection timing comes is during printing on the print medium, the nozzle inspection may be performed when printing on the print medium in the middle of printing is completed.

  Now, nozzle inspection processing performed by the nozzle inspection apparatus according to the present embodiment will be described with reference to the flowcharts of FIGS. FIG. 5 shows a nozzle inspection processing flow performed by the nozzle inspection apparatus of the present embodiment, and FIGS. 6 to 8 show subroutine processing for each inspection mode.

  When the nozzle inspection process shown in FIG. 5 is started, first, information about the print mode is acquired from the print data (step S10). Next, it is determined whether the print data is text data from the acquired information regarding the print mode (step S15).

  In the present embodiment, the CPU 51 reads the data type (image or text) of the print object from the information regarding the print mode, and determines whether the print data is text data. Here, the CPU 51 may read the extension of the print data output from the PC 90 and stored in the RAM 53 as data symbolizing the type of data to be printed. Of course, in addition to the extension, if there is data symbolizing the type of data of the print object, the data may be read.

  If the result of the determination is text data (step S15: YES), nozzle inspection is performed for each nozzle row in inspection mode 1 (step S20). The CPU 51 compares the print mode associated with the inspection mode stored in the ROM 52 with information related to the print mode read from the print data stored in the RAM 53, and selects the inspection mode 1. In the present embodiment, the print mode associated with one of the inspection modes stored in the ROM 52 is text data. However, the present invention is not limited to text data, and any text data such as document data can be used for the inspection mode. 1 may be selected.

  The nozzle inspection in the inspection mode 1 will be described with reference to FIG. In the present embodiment, when text data is printed, it is assumed that the number of consecutive dots missing is within nine, and the inspection mode 1 adds one to the allowable number nine and drives 10 nozzles simultaneously. The content of the process for inspecting the presence or absence of discharge is used. In this way, when nozzles without discharge are detected, there are ten consecutive nozzles without discharge, and it can be detected that the allowable number has been exceeded. Of course, if the allowable number of consecutive missing dots is set according to the printing performance of the printer (for example, printing resolution) and the total number of nozzles provided in the print head, the number corresponding to this allowable number is continuously set. It is preferable that the inspection process contents include whether or not there is a nozzle without ejection.

  Further, in this embodiment, the nozzle inspection in the inspection mode 1 is performed in the order of each YMCK nozzle row, first the Y nozzle row 35Y (see FIG. 3) is selected, and the nozzle inspection processing shown in the flowchart of FIG. 6 is performed. Is done. Thereafter, the inspection process shown in FIG. 6 is sequentially performed on the other M, C, and K nozzle rows. In addition, nozzle inspection processing performed in inspection modes 2 to 4 described later is performed sequentially for all nozzle rows of YMCK as in inspection mode 1.

  When this process starts, “m” indicating the number of nozzle inspection processes is set to 1 (step S201), and 10 nozzles are driven simultaneously (step S202). The CPU 51 outputs nozzle selection signals from the ASIC 61 to PRTs 1 to 10, and as a result, DRVs 1 to 10 are output. Thus, the piezoelectric element is driven so that ink droplets are simultaneously ejected from ten nozzles in one nozzle inspection process.

  Next, the voltage between the measurement terminals is measured (step S203). The CPU 51 operates a voltage measurement circuit (not shown) configured in the ASIC 61 to measure the voltage between the measurement terminals, that is, between the print head 30 and the electrode member 71 (see FIG. 2). Then, it is determined whether or not there is a voltage change for the measured voltage (step S205).

  As a result of the determination, if there is no change in voltage (S205: NO), it is recorded that there is a nozzle without ink droplet ejection (step S206). The CPU 51 writes and records data indicating “exist” in a predetermined recording area provided in the RAM 53. Thereafter, this processing routine ends. That is, in the nozzle inspection for the number of times of the inspection processing, it is found that there are ten consecutive nozzles from which ink droplets are not ejected. Therefore, the inspection in the inspection mode 1 ends at the number of times of the inspection processing.

  On the other hand, if there is a change in voltage as a result of the determination (S205: YES), “m + 1” is newly set as “m” (step S207), and the process proceeds to the next nozzle inspection process. Then, it is determined whether or not “m” is greater than 18 (step S208). If not (NO), since all nozzles have not been inspected for the nozzle row to be inspected, the process returns to step S202. Then, the process of simultaneously driving the next 10 nozzles is performed, and the process from step S203 to S208 is repeated thereafter. If it is determined in step S208 that “m” is greater than 18 (YES), the processing in the inspection mode 1 ends, and the process returns to step S25 (FIG. 5).

  Returning to FIG. 5, in step S <b> 25, it is determined whether there is a non-ejection nozzle. If there is a nozzle without discharge (YES), a cleaning procedure 1 is performed (step S30). The CPU 51 reads data written in a predetermined recording area of the RAM 53 and determines whether data indicating “existence” is written. If data has been written, the cleaning procedure 1 is selected and executed.

  By the way, as a cleaning method that is usually performed, a method is used in which ink clogged in the nozzle is sucked by a suction means (not shown) provided in the cleaning box 18 (see FIG. 1). Then, the number of times of suction and the suction time in one cleaning procedure may be increased or decreased depending on the degree of nozzle clogging. Therefore, since the cleaning procedure 1 performed in step S30 only needs to prevent dot dropouts from continuing, it is only necessary to eliminate clogging of at least one of the 10 consecutive nozzles. The treatment is performed only once, or the treatment is performed with a short suction time. Thus, by performing the cleaning process according to the inspection mode, the time required for the cleaning process in accordance with the inspection mode can be shortened.

  Thereafter, in order to confirm the result of the nozzle cleaning treatment, the process returns to step S20 again to perform the nozzle inspection in the inspection mode 1. As described above, when it is determined in step S25 that there is a nozzle without ejection, the processes in steps S30 and S20 are repeated.

  If it is determined in step S25 that there are no non-ejection nozzles (NO), the nozzle inspection process ends, and if there is print data to be printed thereafter, the print data printing process is performed. Since the data indicating “existence” is not written in the predetermined recording area of the RAM 53, the CPU 51 determines that the non-ejection nozzle does not “exist” and ends the nozzle inspection process. Thereafter, the CPU 51 controls the printing operation of the inkjet printer 10 and starts printing the print data stored in the buffer area of the RAM 53.

  If it is determined in step S15 that the data is not text data (NO), nozzle inspection is performed in inspection mode 2 (step S40). The CPU 51 compares the print mode associated with the inspection mode stored in the ROM 52 with the information regarding the print mode read from the print data stored in the RAM 53, and selects the inspection mode 2. In this embodiment, it is assumed that data other than text data is image data.

  Here, when the print data is image data, as an indispensable condition for the quality of the printed matter to be printed, an allowable number is set for the number of consecutive missing dots in addition to the allowable number for the consecutive number of missing dots. It is assumed that In the present embodiment, for the K nozzle row 35K, up to five consecutive dot omissions are allowed, and for the Y, M, and C nozzle rows 35Y, 35M, and 35C, three consecutive dots are allowed. It is assumed that the allowable number is up to 8 missing spots, up to 4 consecutive missing dots, up to 5 consecutive 5 missing dots. In this case, for all nozzle rows, the number of occurrences of three consecutive dot omissions, which is the smallest number of dot omissions in each nozzle row, is examined, and this occurrence number is 5 for the nozzle row 35K. If the number of nozzle rows 35Y, 35M, and 35C is up to 8 + 5 + 3 = 16, the number of nozzle rows 35Y, 35M, and 35C is less than the allowable number of each nozzle row, which satisfies a sufficient condition for the acceptable quality of the printed matter to be printed.

  Therefore, in the inspection mode 2, first, among the allowable number of consecutive missing dots set for each color nozzle row, the smallest number of nozzles that do not discharge continuously are set to the allowable number +1 as a predetermined number. Whether or not there is a predetermined number or more is the content of the inspection process. In other words, whether or not there is a predetermined number of three nozzles that are not continuously ejected is set as the inspection processing content. Specifically, as described above, the ink droplets are simultaneously ejected from the three nozzles, and the voltage change that occurs when any one of the three nozzles ejects ink exceeds the threshold in advance. This threshold is set. Then, whether or not a predetermined number of three nozzles without continuous ejection are present is checked depending on whether or not the set threshold value is exceeded.

  Of course, when the allowable number for consecutive missing dots is set for each color nozzle row according to the printing performance (for example, the printing resolution) of the printer and the total number of nozzles, the inspection processing contents in the inspection mode 2 are allowed to have these allowable values. It is preferable to determine the continuous number and total number of nozzles without discharge based on the number. Further, the allowable number is set to the predetermined number as it is, and the contents of the inspection process can be determined as to whether or not the predetermined number is exceeded.

  The nozzle inspection in the inspection mode 2 is performed in the order of each YMCK nozzle row, and in this embodiment, first, the Y nozzle row 35Y is selected. Thereafter, the nozzle inspection process shown in the flowchart of FIG. 7 is sequentially performed on the other M, C, and K nozzle rows.

  When this process starts, “p” indicating the number of nozzle inspection processes is set to 1 (step S401), and the three nozzles are driven simultaneously (step S402). The CPU 51 outputs nozzle selection signals from the ASIC 61 to PRT1 to PRT1 to 3, and as a result, DRV1 to DRV3 are output. In this way, the piezoelectric element is driven to eject ink droplets from three nozzles simultaneously in one nozzle inspection process.

  Next, the voltage between the measurement terminals is measured (step S403). The CPU 51 operates a voltage measurement circuit (not shown) configured in the ASIC 61 to measure the voltage between the measurement terminals, that is, between the print head 30 and the electrode member 71 (see FIG. 2). Then, it is determined whether or not there is a voltage change for the measured voltage (step S405).

  If the result of determination is that there is no change in voltage (S405: NO), “1” is added to the number of nozzles without ink droplet ejection and recording is performed (step S406), and processing proceeds to step S407. Each time the CPU 51 determines that there is no change in voltage in step S <b> 405, the CPU 51 adds “1” to the area for recording the number of non-ejection nozzles provided in the RAM 53 and overwrites it. On the other hand, if there is a change in voltage as a result of the determination (S405: YES), the process proceeds to step S407 without doing anything.

  In step S407, “p + 1” is newly set to “p”, and it is determined whether or not “p” is larger than 60 (step S408). Since all the nozzles have not been inspected, the process returns to step S402, the process of simultaneously driving the next three nozzles is performed, and the processes from step S403 to S408 are repeated thereafter.

  If it is determined in step S408 that “p” is greater than 60 (YES), it is determined in step S410 whether the number of nozzles without ejection is equal to or less than a predetermined number. The CPU 51 reads the number of nozzles without ink droplets recorded in the RAM 53 and compares it with a predetermined number, that is, “6 (= 5 + 1)” for the K nozzle row and “17 (= 16 + 1)” for each color nozzle row of YMC.

  As a result of the determination, if the number is greater than or equal to the predetermined number (S410: YES), it is recorded when the allowable number is exceeded (step S411). The CPU 51 records data indicating that the allowable number is exceeded in a predetermined area of the RAM. On the other hand, if it is less than the predetermined number (S410: NO), nothing is done. After the processing from steps S401 to S411 described above is performed for each color nozzle row, the processing in the inspection mode 2 is terminated, and the processing returns to step S45 (FIG. 5).

  Returning to FIG. 5, in step S45, it is determined whether or not the number of non-ejection nozzles in each color nozzle row is equal to or less than the allowable number. The CPU 51 determines whether there is data recorded in the RAM 53 in step S411. As a result of the determination, if there is no recorded data and each color nozzle row is equal to or smaller than the allowable number (S45: YES), the nozzle inspection process is ended, and then the printing process is started.

  On the other hand, as a result of the determination, if there are more color nozzle arrays than the allowable number (S45: NO), the process proceeds to step S50, and a process of inspecting each color nozzle array in the inspection mode 3 is performed. In the present embodiment, for each color nozzle row, the nozzle number (position) where ink is not ejected is examined, and the content of the inspection processing for detecting whether or not there are a predetermined number or more of non-ejection nozzles that are different from each other is examined. Mode 3 is assumed. Specifically, the nozzles to be inspected are selected one by one and ink droplets are ejected, and the position and number of nozzles from which ink enemies are not ejected are inspected. As a result, the continuous number of nozzles that do not eject ink droplets is determined from the position and number of nozzles that do not eject ink droplets.Therefore, it is determined whether or not there are a predetermined number or more of nozzles that do not eject ink droplets. It becomes possible to detect.

  As described above, when the print target is image data, the indispensable condition for the acceptable quality of missing dots is set for each color nozzle row, and therefore, the inspection mode 3 inspects whether or not this essential condition is satisfied. To be implemented. Therefore, in this embodiment, the nozzle inspection in the inspection mode 3 is performed on the color nozzle rows that do not satisfy the allowable number in the inspection in the inspection mode 2.

  Of course, it may be performed for all the color nozzle rows. Even in a nozzle row that satisfies a sufficient condition, there may be rare cases where the number of nozzles without ejection increases due to the cleaning procedure 2 performed in step S60. In such a case, if the nozzle position is detected in the inspection mode 3, it is possible to identify the nozzle that has not ejected, and to perform a cleaning process suitable for the identified nozzle.

  The nozzle inspection in the inspection mode 3 will be described with reference to FIG. When this process starts, “q” indicating the number of nozzle inspection processes is set to 1 (step S501), and the qth, that is, the first nozzle is driven (step S502). The CPU 51 outputs the nozzle selection signal of PRT1 from the ASIC 61, and as a result, DRV1 is output. Thus, the piezoelectric element is driven to eject ink droplets from one nozzle in one nozzle inspection process.

  Next, the voltage between the measurement terminals is measured (step S503). The CPU 51 operates a voltage measurement circuit (not shown) configured in the ASIC 61 to measure the voltage between the measurement terminals, that is, between the print head 30 and the electrode member 71 (see FIG. 2). Then, it is determined whether or not there is a voltage change for the measured voltage (step S505).

  If there is no change in voltage as a result of the determination (S505: NO), the nozzle row and the nozzle number (q) are recorded (step S506), and the process proceeds to step S507. Each time the CPU 51 determines that there is no voltage change in step S505, the CPU 51 additionally records the nozzle row and nozzle number being inspected in the area for recording the nozzle row and nozzle number provided in the RAM 53. On the other hand, if there is a change in voltage as a result of determination (S505: YES), the process proceeds to step S507 without doing anything.

  In step S507, “q + 1” is newly set as “q”, and it is determined whether or not “q” is greater than 180 (step S508). Since all the nozzles have not been inspected, the process returns to step S502, the process for driving the next second nozzle is performed, and the processes from step S503 to S508 are repeated thereafter.

  If it is determined in step S508 that “q” is greater than 180 (YES), the number of continuous non-discharge nozzles and the number of consecutive non-discharge nozzles generated are calculated in step S509. The CPU 51 calculates the number of consecutive numbers and the number of occurrences of these numbers from the nozzle row and nozzle number recorded in step S506.

  Next, in step S510, it is determined whether or not the number of consecutive occurrences and the number of occurrences of each nozzle row are equal to or greater than a predetermined number. In the present embodiment, for Y, M, and C nozzle rows 35Y, 35M, and 35C, up to eight consecutive dot omissions, up to four consecutive dot omissions, and five consecutive dot omissions. Since the predetermined number is up to three locations, the CPU 51 determines whether there are five or more continuous non-discharge nozzles, and whether there are four (= 3 + 1) or more consecutive non-discharge nozzles. Further, it is determined whether or not there are 6 (= 5 + 1) or more consecutive nozzles without discharge, and whether or not there are 9 (= 8 + 1) or more consecutive nozzles without discharge.

  As a result of the determination, if there is a continuous number exceeding the predetermined number, or if the number of occurrences of each continuous number exceeds the predetermined number (S510: YES), recording is performed when the allowable number is exceeded. (Step S511). The CPU 51 records data indicating that the allowable number is exceeded in a predetermined area of the RAM. On the other hand, if it is less than the predetermined number (S510: NO), nothing is done. After the processing from step S501 to S511 described above is performed for each color nozzle row, the processing in inspection mode 3 is terminated, and the process returns to step S55 (FIG. 5).

  Returning to FIG. 5, in step S55, it is determined whether or not the number of non-ejection nozzles in each color nozzle row is equal to or less than the allowable number. The CPU 51 determines whether there is data recorded in the RAM 53 in step S511. If it is determined that there is no print data and each color nozzle row is equal to or less than the allowable number (S55: YES), the nozzle inspection process is terminated, and if there is still print data to be printed, the print process is started. Will be.

  On the other hand, as a result of the determination, if there are more color nozzle rows than the allowable number (S55: NO), the process proceeds to step S60 and the cleaning procedure 2 is performed. Thereafter, in order to confirm the result of the nozzle cleaning treatment, the process returns to step S40 again to perform the inspection process in the inspection mode 2, and the processes after step S40 described above are repeated.

  By the way, the cleaning procedure 2 performed in step S60 is more likely to identify the nozzle that should eliminate the nozzle clogging than the cleaning procedure 1 performed in step S30. In order to solve this problem, it is recommended to perform the suction treatment a plurality of times. Thus, by changing the cleaning treatment method according to the inspection mode, it is possible to perform the cleaning treatment according to the inspection mode, and it is possible to suppress unnecessarily increasing the time required for the cleaning treatment.

  By repeating such a process, there is no nozzle that does not discharge three ink droplets continuously, or there are nozzles that do not discharge ink droplets three consecutively. If the number is less than or equal to the allowable number determined for each column, the nozzle inspection process ends. Thereafter, the CPU 51 controls the printing operation of the ink jet printer and starts printing the print data stored in the buffer area of the RAM 53.

  As described above, the nozzle inspection time can be shortened by performing the nozzle inspection processing shown in FIG. That is, in the inspection mode 1, the text data is subjected to nozzle inspection by simultaneously driving the number of nozzles of +1 with respect to the allowable number of consecutive missing dots. Therefore, for example, if ten nozzles are driven at a time, the inspection is performed 10 times faster than when the nozzles are driven one by one, and the time required for the nozzle inspection can be shortened. In addition, when the nozzle inspection is performed again after the cleaning treatment to confirm the cleaning treatment result, the nozzle inspection time is shortened by the number of times such inspection is performed. It gets bigger.

  Further, in the inspection mode 2, the nozzle inspection is performed by simultaneously driving the same number of nozzles as the smallest continuous number among the continuous number of missing dots provided with an allowable number for the image data. Therefore, for example, if three nozzles are driven at a time, the inspection is performed three times faster than when the nozzles are driven one by one. Therefore, it is possible to shorten the time required for the nozzle inspection. Further, when the nozzle inspection is performed again to confirm the cleaning treatment result after the cleaning treatment, the nozzle inspection time is shortened by the number of times such inspection mode 2 is performed, and the inspection time is shortened. The effect is even greater.

  By the way, the inspection mode 3 is basically a nozzle inspection method in which nozzles are inspected one by one, and is an inspection method performed in the conventional nozzle inspection as in the above-mentioned Patent Document 1. Therefore, when the inspection mode 3 is performed subsequent to the nozzle inspection in the inspection mode 2 (step S45: NO), the extra nozzle inspection in the inspection mode 2 is inspected with respect to the conventional nozzle inspection. However, when the inspection mode 3 is not continuously performed (step S45: YES), the nozzle inspection is only the inspection mode 2, and the nozzle inspection time is considerably shortened. That is, when it is assumed that there is a low probability that nozzles that do not normally eject ink droplets are continuously present, the nozzle inspection corresponding to the print mode is performed by performing the nozzle inspection in the inspection mode 2 before the inspection mode 3. Can be appropriately performed, the nozzle inspection time can be shortened, and the time until printing can be shortened.

  As described above, the present invention is a print mode in which the print speed is mainly given priority in various print modes, for example, in the print mode such as monochrome print, low resolution print, draft print, etc. in addition to the text print described above. In the inspection mode, it is possible to shorten the inspection time by adopting an inspection mode in which the number of nozzles to be inspected that simultaneously eject ink is larger. On the other hand, in print modes in which print quality is given priority, for example, in the print mode such as color printing and high-resolution printing in addition to the above-described image printing, in the inspection mode, more nozzles to be inspected are simultaneously ejected. By adopting an inspection mode with a small number of nozzles, it is possible to grasp the existence of non-ejection nozzles in more detail.

  As mentioned above, although this invention was demonstrated using one embodiment, this invention is not limited to such embodiment at all, and can be implemented with various forms within the range which does not deviate from the meaning of this invention. Of course.

  For example, in the above-described embodiment, the nozzle inspection in the inspection mode 3 performed in step S50 of FIG. 5 is the inspection processing content for specifying the nozzle row and the nozzle position. The content of the process for inspecting whether or not the number of nozzles that do not eject ink is a predetermined number or more may be used. This is referred to as inspection mode 4. According to the inspection in the inspection mode 4, since it is inspected whether the number of missing dots is within the allowable number or not, for example, the printed object is not defective regardless of the color like high-definition image data. This is an inspection suitable for the nozzle inspection in the case where the number affects the printed print quality.

  The inspection mode 4 will be described with reference to FIG. The processing steps in the inspection mode 4 shown in FIG. 9 are different from the processing steps in the inspection mode 3 shown in FIG. 8 in the processing contents in the step S506a, and therefore the processing in the step S509 is unnecessary. Except for this, all are the same processing steps. Therefore, only step S506a will be described here, and description of other processing steps will be omitted.

  In step S506a in the inspection mode 4, if it is determined in step S505 that there is no voltage change (NO), the inspection nozzle is a nozzle that does not eject ink droplets, and therefore, the process of adding one to the number of nozzles without ejection and recording is performed. I do. The CPU 51 adds “1” to the area for recording the number of non-ejection nozzles in the RAM 53 every time a non-ejection nozzle is detected. Therefore, when the nozzle inspection in the inspection mode 4 is completed for all the nozzle arrays of YMCK, the RAM 53 records a numerical value indicating how many nozzles out of all the nozzles are those without ink droplet ejection.

  Note that when the inspection mode 4 is performed in step S50, the cleaning treatment in step S60 performed when it is determined “NO” as a result of the determination process in step S55 is, for example, suction as described above. It is preferable to use a cleaning method suitable for the inspection mode 4 such as increasing or decreasing the number of times. In this way, it is possible to prevent the time required for the cleaning treatment from becoming unnecessarily long.

  Further, in the above embodiment, when the print object is image data, the nozzle inspection in the inspection mode 2 is performed in step S40. However, the nozzle inspection in the inspection mode 1 may be performed. Even in the case of image data, if a predetermined number or more of consecutive missing dots have not occurred, if the actually printed image is acceptable, nozzle inspection in inspection mode 1 is a suitable inspection, and inspection mode The inspection time can be shortened with respect to 2.

  In the above embodiment, in the inspection mode 2, it is determined whether or not all three nozzles are not ejecting ink droplets. However, at least one of the three nozzles is not ejected. It may be inspected whether or not. Specifically, as described above, a threshold value TH2 is set so that the voltage change when one of the three nozzles does not eject ink droplets does not exceed the threshold value. Ink droplet ejection inspection is performed using Further, when the inspection mode 2 is set to such an inspection mode 2a, when it is determined that the number of nozzles without ink droplet ejection is larger than the allowable number (FIG. 5, step S45: NO), the nozzles according to the inspection mode 3 A cleaning procedure may be performed immediately without performing an inspection.

  In this way, when printing a printing object that requires the highest print quality that does not allow any nozzles that do not eject ink droplets, such an inspection can be performed without performing a nozzle inspection for each nozzle. Since it is possible to determine whether or not at least one nozzle that does not eject ink droplets exists in the mode 2a, the inspection mode 2a is effective. Further, since the cleaning process is performed without performing the nozzle inspection in the inspection mode 3, it is possible to shorten the nozzle inspection time.

  Further, in the above embodiment, when the print object is text data, the nozzle inspection in the inspection mode 1 is performed in step S20. However, the nozzle inspection in the inspection mode 2 may be performed. Even in the case of text data, if a large number of consecutive missing dots occur, and the print quality of the printed matter that is actually printed becomes unacceptable, nozzle inspection in inspection mode 2 is a suitable inspection. In this case, although the inspection time is longer with respect to the inspection mode 1, the nozzle inspection can be performed in a shorter time than inspecting the nozzles one by one. Of course, if text data requires high-definition print quality, nozzle inspection may be performed in inspection mode 3 or inspection mode 4.

  In the above embodiment, the inspection mode is selected based on the data type (image or text) of the print target in step S15 in FIG. 5. Alternatively, the selection may be made based on other designation information set as information on the print mode, such as color printing or monochrome printing. Or it is good also as selecting based on several designation | designated information among these designation | designated information. In this way, it is possible to perform nozzle inspection for obtaining print quality suitable for the printing method specified by the print data.

  In the inspection mode 1 and the inspection mode 2 in the above embodiment, the number of nozzles that is one more than the allowable number of consecutive missing dots is driven simultaneously in one processing step. The number of nozzles may be driven simultaneously.

  For example, in the inspection mode 1, for the 10 inspection target nozzles of interest, there are five consecutive non-ejection nozzles from the next 10 inspection target nozzles that are continuously driven, and the next 10 inspection target nozzles , Suppose that there are five consecutive non-ejection nozzles from the ten inspection target nozzles of interest. At this time, as is apparent from the above description, it is determined that each of the 10 inspection target nozzles is ejected, and as a result, there are no 10 consecutive nozzles without ejection. However, in reality, there are 5 non-discharge nozzles between the 10 inspection target nozzles to be noticed and the next 10 inspection target nozzles, so there are 10 continuous non-discharge nozzles. become. Therefore, in such a case, if the number of nozzles driven simultaneously in one inspection process is five, ten nozzles without discharge are detected continuously by detecting the absence of nozzle discharge for two inspection processes. Can be detected. Thus, if the number of nozzles smaller than the allowable number is driven simultaneously, the effect of shortening the nozzle inspection time is reduced, but the allowable number of nozzles can be accurately detected.

  In the above-described embodiment, a unit signal that is continuous for 8 segments is output (ON) for each nozzle, and a head drive signal that does not output an 8-segment unit signal (OFF) is generated. The output time of the unit signal may be increased or decreased by setting the segment to 4 or 16 segments, or the time when the unit signal is not output may be set to 4 or 16 segments. Of course, as described with reference to FIG. 4, conditions for facilitating detection such as a significant change in the voltage Ve appear in advance, and the number of segments for which the unit signal is turned “ON” or “OFF” is determined according to the conditions. It is preferable. By doing so, it is easy to detect a voltage change between the measurement terminals, and the nozzle inspection accuracy is increased.

  In the above embodiment, the piezoelectric element is driven to eject ink droplets from the nozzle. However, the ink is heated by applying a voltage to a heating resistor (for example, a heater) and the ink is generated by the generated bubbles. The ink droplets may be ejected by applying pressure. In this way, the nozzle inspection apparatus of the present invention can be applied to an ink jet printer that does not use a piezoelectric element.

  In the above embodiment, as shown in FIG. 2, the presence or absence of ejection of ink droplets from the nozzles is detected using the voltage change between the measurement terminals due to ejection of charged ink droplets. For example, other detection methods such as a method using light disclosed in Patent Document 1 may be used. As an example, FIG. 10 shows a method using light.

  FIG. 10 shows a state in which three nozzles are inspected for each nozzle row 35M of the print head 30. Nozzles n = 1 to 3, n = 4 to 6,... 3 at a time. Two nozzles are inspected. As shown in the figure, assuming that ink droplets are ejected from three nozzles n = 4 to n = 6 indicated by shading, the laser light L emitted from the light emitting unit 91 is ejected from the ink. Blocked by drops. For this reason, if an ink droplet is ejected from at least one of the three nozzles, a non-light-receiving time occurs during which the laser beam L does not reach the light receiving unit 92 while being blocked by the ink droplet. In other words, when ink droplets are not ejected from all three nozzles, no light reception time is generated. Therefore, this non-light receiving time is detected, and if there is no non-light receiving time when the nozzle is driven, all three nozzles can be detected as nozzles without ejection of ink droplets.

  DESCRIPTION OF SYMBOLS 10 ... Inkjet printer, 11-14 ... Ink cartridge, 17 ... Frame, 18 ... Cleaning box, 20 ... Carriage, 21 ... Guide, 25 ... Print medium, 26 ... Drive motor, 30 ... Print head, 31 ... Driver board, 32 ... Piezoelectric element, 33 ... Member, 34 ... Nozzle plate, 35 ... Nozzle, 35Y-35K ... Nozzle array, 38 ... Ink, 39 ... Ink droplet, 40 ... Carriage motor, 41 ... Carriage belt, 45 ... Flexible substrate, 50 ... Main board 51 ... CPU 51a ... Inspection mode storage unit 51b ... Print mode information acquisition unit 51c ... Inspection mode selection unit 51d ... Nozzle inspection unit 51e ... Cleaning treatment selection unit 52 ... ROM 53 ... RAM 54 ... Flash memory, 55 ... I / F, 60 ... Sub-board, 61 ... ASI 62 ... Voltage generating circuit, 64 ... Resistance, 65 ... Connection member, 66 ... Connection member, 70 ... Inspection box, 71 ... Electrode member, 72 ... Ink absorber, 90 ... PC, 91 ... Light emitting unit, 92 ... Light receiving unit .

Claims (12)

A nozzle inspection device that inspects whether or not the recording liquid is ejected from the plurality of nozzles for a plurality of nozzles for ejecting the recording liquid according to a printing mode and printing a print object on a medium,
For the inspection of whether or not the recording liquid is discharged, an inspection mode storage unit that stores a plurality of inspection modes that define inspection processing contents;
A print mode information acquisition unit for acquiring information on the print mode associated with the print job from a print job to be printed on the medium;
An inspection mode selection unit that selects one inspection mode from the plurality of stored inspection modes based on the acquired information about the print mode;
A nozzle inspection device comprising: a nozzle inspection unit that inspects whether or not the recording liquid is discharged according to the selected one inspection mode. The nozzle inspection device according to claim 1,
The nozzle inspection apparatus, wherein the inspection mode storage unit stores at least one of the plurality of inspection modes as an inspection mode in which the recording liquid is simultaneously ejected from a plurality of inspection target nozzles. The nozzle inspection device according to claim 2,
When the information on the print mode acquired by the print mode information acquisition unit is information on a print mode for printing a printed matter of text, the inspection mode selection unit simultaneously receives the recording liquid from the plurality of inspection target nozzles. A nozzle inspection apparatus, wherein an inspection mode for inspecting by discharging is selected. A nozzle inspection device according to any one of claims 1 to 3,
According to the selected inspection mode based on the inspection result of the nozzle inspection performed by the nozzle inspection unit, having a plurality of cleaning treatments for cleaning the nozzles that do not eject the recording liquid with different recovery processes. A nozzle inspection apparatus, further comprising: a cleaning treatment selection unit that selects a cleaning treatment from the plurality of cleaning treatments. A nozzle inspection device that inspects whether or not the recording liquid is ejected from the plurality of nozzles for a plurality of nozzles that eject the recording liquid and print a print target on the medium,
An inspection process in which a plurality of inspection target nozzles are selected from the plurality of nozzles, and the recording liquid is simultaneously discharged from the selected plurality of inspection target nozzles to inspect whether or not the recording liquid is discharged is set as a first inspection mode. An inspection mode storage unit for storing;
And a nozzle inspection unit that inspects whether or not the recording liquid is discharged in accordance with the first inspection mode. The nozzle inspection device according to claim 5,
The inspection mode storage unit further stores an inspection process different from the first inspection mode as a second inspection mode,
The nozzle inspection unit inspects whether or not the recording liquid is ejected in accordance with the second inspection mode based on a nozzle inspection result in the first inspection mode. The nozzle inspection device according to claim 6,
The second inspection mode is an inspection mode in which the recording liquid is ejected for each of the plurality of nozzles to inspect whether or not the recording liquid is ejected. A nozzle inspection device according to any one of claims 5 to 7,
According to the selected inspection mode based on the inspection result of the nozzle inspection performed by the nozzle inspection unit, having a plurality of cleaning treatments for cleaning the nozzles that do not eject the recording liquid with different recovery processes. A nozzle inspection apparatus, further comprising: a cleaning treatment selection unit that selects a cleaning treatment from the plurality of cleaning treatments. A nozzle inspection device according to any one of claims 1 to 8,
The nozzle inspection unit applies a voltage between the recording liquid and a receiving area where the recording liquid is landed after being ejected from the nozzle, and based on the change in the voltage generated along with the ejection of the recording liquid, A nozzle inspection apparatus for inspecting whether or not a recording liquid is discharged. A nozzle inspection method for inspecting whether or not the recording liquid is discharged from the plurality of nozzles for a plurality of nozzles for discharging a recording liquid according to a printing mode and printing a print target on a medium,
An inspection mode storage step for storing a plurality of inspection modes defining inspection processing contents for the inspection of whether or not the recording liquid is discharged;
A print mode information acquisition step for acquiring information on the print mode associated with the print job from a print job to be printed on the medium;
An inspection mode selection step of selecting one inspection mode from the plurality of stored inspection modes based on the acquired information about the print mode;
And a nozzle inspection step for inspecting whether or not the recording liquid is discharged according to one inspection mode selected in the previous period. A nozzle inspection method for inspecting whether or not the recording liquid is ejected from the plurality of nozzles for a plurality of nozzles for ejecting the recording liquid and printing a print target on the medium,
An inspection process in which a plurality of inspection target nozzles are selected from the plurality of nozzles, and the recording liquid is simultaneously discharged from the selected plurality of inspection target nozzles to inspect whether or not the recording liquid is discharged is set as a first inspection mode. An inspection mode storage step for storing;
A nozzle inspection step for inspecting whether or not the recording liquid is discharged in accordance with the first inspection mode.   The program for making a computer perform each procedure of the nozzle test | inspection method of Claim 10 or 11.

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