JP2018153922A - Cleaning time prediction device and print system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a proper cleaning time.SOLUTION: A control device 140 of a cleaning time prediction device 130 comprises: a defective state coefficient determination part 146 for, based on a check pattern, determining a defective state coefficient in which a state of a discharge failure of a nozzle is digitized; a standby time coefficient determination part 148 for determining a standby time coefficient based on a standby time; a defective frequency coefficient determination part 150 for determining a defective frequency coefficient based on a defective frequency of the nozzle; a prediction feature amount calculation part 152 for calculating a prediction feature amount, based on the defective state coefficient, the standby time coefficient and the defective frequency coefficient; and a cleaning time prediction part 154 for, based on a feature amount table T2 in which an actual cleaning time and an actual feature amount are associated, predicting a cleaning time corresponding to the prediction feature amount, and by which it is estimated that the discharge failure of the nozzle is dissolved.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a cleaning time prediction apparatus and a printing system.

  2. Description of the Related Art Conventionally, ink jet printers that detect the discharge state of ink from nozzles and perform cleaning according to the discharge state are known. For example, Patent Document 1 discloses a check pattern for confirming the discharge state of a nozzle. The check pattern is an inspection image for confirming whether or not the nozzle has an ejection failure due to clogging or the like, and is an image printed on a recording medium.

  For example, when a nozzle out of a plurality of nozzles cannot eject ink due to defective ejection, the check pattern printed on the recording medium has a missing ink dot at a position where the nozzle should eject ink. Occur. As described above, when the nozzle is in any ejection failure state, some defect appears in the check pattern. By periodically printing such a check pattern, it is possible to periodically check the ejection state of each nozzle in the inkjet printer. The ink jet printer disclosed in Patent Document 1 includes a receiving unit capable of inputting whether or not the ink head is to be cleaned after the user visually confirms the check pattern printed on the recording medium. ing. Then, when the reception unit is instructed to perform cleaning, cleaning is performed.

JP 2011-161753 A

  By the way, whether or not cleaning is performed and how long the cleaning is performed are determined by the user visually confirming the check pattern. In particular, the cleaning time has been determined by the user's rule of thumb. For this reason, since the cleaning execution time is short, even after the cleaning is performed, the nozzle ejection failure may not be solved. Further, since the cleaning time is too long, the cleaning has been performed for a time longer than necessary.

  The present invention has been made in view of this point, and an object thereof is to provide a cleaning time predicting apparatus and a printing system capable of setting the cleaning execution time to an appropriate time.

  A cleaning time prediction apparatus according to the present invention includes an ink head having a plurality of nozzles for discharging ink, and an inkjet printer capable of printing a check pattern capable of confirming the discharge state of the nozzles eliminates the discharge failure of the nozzles. This is a cleaning time predicting device for predicting the cleaning time for performing the cleaning. The cleaning time prediction device includes a control device. The control device includes a storage unit, a failure state coefficient determination unit, a standby time coefficient determination unit, a failure frequency coefficient determination unit, and a predicted feature amount calculation unit. The storage unit stores in advance a standby time of the ink jet printer and a failure frequency which is the number of times that the nozzle discharge failure has occurred within a predetermined time. The defective state coefficient determination unit determines a defective state coefficient obtained by quantifying the discharge failure state of the nozzle based on the check pattern. The standby time coefficient determination unit determines a standby time coefficient that is a coefficient used to calculate a feature amount that is an index for predicting the cleaning time based on the standby time. The defect frequency coefficient determination unit determines a defect frequency coefficient that is a coefficient used for calculating the feature amount based on the defect frequency. The predicted feature amount calculation unit calculates a predicted feature amount that is the feature amount based on the defect state coefficient, the standby time coefficient, and the defect frequency coefficient. The storage unit stores in advance a feature amount table in which an actual cleaning time that is an actual cleaning time and an actual feature amount that is the feature amount corresponding to the actual cleaning time are associated with each other. The control device includes a cleaning time prediction unit that predicts a cleaning time that is a cleaning time corresponding to the predicted feature amount and is estimated to eliminate the ejection failure of the nozzle based on the feature amount table. I have.

  The required cleaning time varies depending on the state of nozzle ejection failure. Further, it can be said that the longer the waiting time, the more the ink is solidified, and the longer the cleaning time. It can be said that the higher the defect frequency, the easier the nozzle ejection defects occur and the longer the cleaning time. Therefore, according to the cleaning time predicting apparatus, the predicted feature amount used when predicting the cleaning time is based on a defect state coefficient, a standby time coefficient, and a defect frequency coefficient that are coefficients that affect the cleaning time. Is calculated. Then, the cleaning time corresponding to the predicted feature amount is predicted using a feature amount table showing the relationship between the actual cleaning time actually performed and the actual feature amount. Thus, by predicting the cleaning time based on a coefficient that is likely to affect the cleaning time, an appropriate cleaning time can be predicted. In addition, since the cleaning time corresponding to the predicted feature amount is predicted using the feature amount table showing the relationship between the actual cleaning time and the actual feature amount, the cleaning time corresponding to the ink head of the target inkjet printer is used. Can be set.

  According to the present invention, the cleaning time can be set to an appropriate time.

It is a front view of the inkjet printer of the printing system which concerns on embodiment. FIG. 3 is a schematic diagram illustrating a configuration of a surface of a carriage that faces a recording medium. It is a front view which shows the structure of the periphery of a capping apparatus. 1 is a block diagram of a printing system. It is a schematic diagram which shows an example of a check pattern. It is a schematic diagram of a check pattern showing a first defective state. It is a schematic diagram of a check pattern showing a second defective state. It is a schematic diagram of the check pattern which shows a 3rd defect state. It is a schematic diagram of the check pattern which shows a 4th defect state. It is a schematic diagram of the check pattern which shows a 5th defect state. It is a schematic diagram of the check pattern which shows a 6th defect state. It is a schematic diagram of the check pattern which shows a 7th defect state. It is a figure which shows an example of a defect state coefficient table. It is the flowchart shown about the procedure which estimates cleaning time and implements cleaning with the estimated cleaning time. It is a figure which shows an example of a feature-value table. It is a figure which shows the relationship between each estimated feature-value and estimated cleaning time.

  Hereinafter, a printing system including a cleaning time predicting apparatus according to an embodiment of the present invention will be described with reference to the drawings. It should be noted that the embodiments described here are not intended to limit the present invention. In addition, members / parts having the same action are denoted by the same reference numerals, and overlapping descriptions are omitted or simplified as appropriate.

  FIG. 1 is a front view of an inkjet printer 10 of a printing system 100 according to the present embodiment. In the following description, when the ink jet printer (hereinafter also referred to as a printer) 10 is viewed from the front, the direction away from the printer 10 is the front, and the direction approaching the printer 10 is the rear. Left, right, top, and bottom mean left, right, top, and bottom when the printer 10 is viewed from the front. Further, the symbols F, Rr, L, R, U, and D in the drawings mean front, rear, left, right, upper, and lower, respectively. In addition, the symbol Y in the drawing indicates the main scanning direction. Here, the main scanning direction Y is the left-right direction. Reference numeral X indicates the sub-scanning direction. Here, the sub-scanning direction X is the front-rear direction, and is orthogonal to the main scanning direction Y in plan view. However, the above direction is only a direction determined for convenience of description, and does not limit the installation mode of the printer 10 at all, and does not limit the present invention. In the present embodiment, the sub-scanning direction X corresponds to the “first direction” of the present invention. The main scanning direction Y corresponds to the “second direction” of the present invention.

  As shown in FIG. 1, the printing system 100 includes a printer 10 and a cleaning time predicting device 130. The printer 10 is an ink jet printer. The printer 10 is a so-called large printer that is long in the main scanning direction Y as compared with a home printer. For example, the printer 10 is a business printer. In the present embodiment, the printer 10 sequentially moves the roll-shaped recording medium 5 forward and ejects ink from the ink heads 40, 50, 60, and 70 (see FIG. 2) that move in the main scanning direction Y. Thus, an image is printed on the recording medium 5. Hereinafter, the ink heads 40, 50, 60, and 70 are appropriately described as ink heads 40 to 70.

  The recording medium 5 is an object on which an image is printed. Note that the type of the recording medium 5 is not particularly limited. The recording medium 5 may be paper such as plain paper or inkjet printing paper. The recording medium 5 may be a transparent sheet made of resin such as polyvinyl chloride (PVC) or polyester, or glass. The recording medium 5 may be a sheet made of metal or rubber.

  As shown in FIG. 1, the printer 10 includes a printer main body 10 a, a leg 11, an operation panel 12, and a platen 16. The printer main body 10a has a casing extending in the main scanning direction Y. The legs 11 support the printer main body 10a, and are provided on the lower surface of the printer main body 10a. The operation panel 12 is provided on the right front surface of the printer main body 10a, for example. However, the position of the operation panel 12 is not particularly limited. For example, the operation panel 12 is used by a user to perform operations related to printing. Although illustration is omitted, for example, information related to printing such as resolution and ink density, a display unit that displays the status of the printer 10 during printing, and information related to printing are input to the operation panel 12. An input unit is provided.

  The platen 16 supports the recording medium 5 when printing on the recording medium 5. The recording medium 5 is placed on the platen 16. Printing on the recording medium 5 is performed on the platen 16. The platen 16 extends in the main scanning direction Y. In the present embodiment, the platen 16 corresponds to the “mounting portion” of the present invention.

  In the present embodiment, the printer 10 includes a head moving mechanism 31 and a medium transport mechanism 32. The head moving mechanism 31 is a mechanism that moves the ink heads 40 to 70 (see FIG. 2) in the main scanning direction Y relative to the recording medium 5 placed on the platen 16. In the present embodiment, the head moving mechanism 31 moves the ink heads 40 to 70 in the main scanning direction Y. The configuration of the head moving mechanism 31 is not particularly limited. In the present embodiment, the head moving mechanism 31 includes a guide rail 20, a pulley 21, a pulley 22, an endless belt 23, a carriage motor 24, and a carriage 30. The guide rail 20 guides the movement of the carriage 30 in the main scanning direction Y. The guide rail 20 is disposed above the platen 16. The guide rail 20 extends in the main scanning direction Y. The pulley 21 is provided at the left end portion of the guide rail 20. The pulley 22 is provided at the right end portion of the guide rail 20. The belt 23 is wound around the pulley 21 and the pulley 22. In the present embodiment, a carriage motor 24 is connected to the right pulley 22. However, the carriage motor 24 may be connected to the left pulley 21. Here, when the carriage motor 24 is driven and the pulley 22 rotates, the belt 23 travels between the pulley 21 and the pulley 22.

  The carriage 30 is attached to the belt 23. The carriage 30 is engaged with the guide rail 20 and is slidably provided on the guide rail 20. Ink heads 40 to 70 (see FIG. 2) are mounted on the carriage 30. In the present embodiment, as the belt 23 travels by driving the carriage motor 24 and the carriage 30 moves in the main scanning direction Y, the ink heads 40 to 70 mounted on the carriage 30 move in the main scanning direction Y. To do.

  The medium transport mechanism 32 moves the recording medium 5 placed on the platen 16 in the sub-scanning direction X relative to the ink heads 40 to 70. Here, the medium transport mechanism 32 moves the recording medium 5 placed on the platen 16 in the sub-scanning direction X. The configuration of the medium transport mechanism 32 is not particularly limited. In the present embodiment, the medium transport mechanism 32 includes a grit roller 25, a pinch roller 26, and a feed motor 27 (see FIG. 4). The grit roller 25 is provided on the platen 16. Here, a part of the grit roller 25 is embedded in the platen 16. The pinch roller 26 presses the recording medium 5 from above. The pinch roller 26 is disposed above the grit roller 25 so as to face the grit roller 25 in the vertical direction. The pinch roller 26 may be configured to be movable in the vertical direction according to the thickness of the recording medium 5. The arrangement position and the number of the grit roller 25 and the pinch roller 26 are not particularly limited. In the present embodiment, the grit roller 25 and the pinch roller 26 are respectively disposed at the left end portion and the right end portion of the platen 16. As shown in FIG. 4, the feed motor 27 is connected to the grit roller 25. When the feed motor 27 is driven and the grit roller 25 rotates while the recording medium 5 is sandwiched between the grit roller 25 and the pinch roller 26, the recording medium 5 is conveyed in the sub-scanning direction X.

  FIG. 2 is a schematic diagram showing the configuration of the surface (the lower surface in the present embodiment) of the carriage 30 that faces the recording medium 5. FIG. 2 is a view of the lower surface of the carriage 30 as viewed upward. As shown in FIG. 2, the printer 10 includes ink heads 40, 50, 60, and 70. The ink heads 40 to 70 are held on the lower surface of the carriage 30. The ink heads 40 to 70 are disposed above the platen 16 (see FIG. 1), and are slidably provided on the guide rail 20 (see FIG. 1) via the carriage 30. The ink heads 40 to 70 are moved in the main scanning direction Y along the guide rail 20 by the head moving mechanism 31. The ink heads 40 to 70 are arranged side by side in the main scanning direction Y. Specifically, the ink heads 40, 50, 60, and 70 are arranged in order from the left side. Here, the number of ink heads 40 to 70 is four. However, the number of ink heads 40 to 70 is not particularly limited.

  Each of the ink heads 40 to 70 is connected to an ink cartridge that stores ink of different colors. In the present embodiment, the ink head 40 ejects magenta ink. The ink head 50 ejects yellow ink. The ink head 60 discharges cyan ink. The ink head 70 discharges black ink. However, the types of ink colors ejected from the ink heads 40 to 70 are not limited to the above four types. Moreover, the material of the ink is not limited at all, and various materials used as the ink material of the conventional ink jet printer can be used. The ink may be, for example, a solvent (solvent) pigment ink or an aqueous pigment ink, an aqueous dye ink, or an ultraviolet curable pigment ink that is cured by receiving ultraviolet rays.

  As shown in FIG. 2, the plurality of ink heads 40 to 70 each have a plurality of nozzles arranged in the sub-scanning direction X. Specifically, the ink head 40 has a plurality of nozzles 41. The ink head 50 has a plurality of nozzles 51. The ink head 60 has a plurality of nozzles 61. The ink head 70 has a plurality of nozzles 71. The nozzles 41, 51, 61, and 71 are portions from which ink is ejected. Hereinafter, the nozzles 41, 51, 61, and 71 are appropriately described as nozzles 41 to 71. In FIG. 2, each of the ink heads 40, 50, 60, and 70 has 10 nozzles, but actually, more (for example, 180) nozzles are formed. The length of each ink head 40, 50, 60, 70 in the sub-scanning direction X is, for example, 1 inch. Therefore, in the above case, the ink discharge density is 180 dpi (dot per inch). However, the length of each ink head 40 to 70 in the sub-scanning direction X and the number of nozzles included in each ink head 40 to 70 are not limited at all.

  FIG. 3 is a front view showing a configuration around the capping device 90. As shown in FIG. 3, the printer 10 includes a capping device 90. The capping device 90 includes a cap 91, a cap moving mechanism 92, and a suction pump 93. The cap 91 and the cap moving mechanism 92 are disposed at the home position HP located at the right end portion of the guide rail 20. Here, the home position HP is a position where the carriage 30 and the ink heads 40 to 70 wait when printing is waiting, that is, when printing is not being performed. However, the position of the home position HP is not particularly limited, and may be the left end portion of the guide rail 20.

  The cap 91 is a member that suppresses clogging of the nozzles 41 to 71 due to the ink adhering to the nozzles 41 to 71 (see FIG. 2) of the ink heads 40 to 70 being cured. The cap 91 is attached to the ink heads 40 to 70 from below so as to cover the nozzles 41 to 71 during printing standby. The cap moving mechanism 92 supports the cap 91. The cap moving mechanism 92 is a mechanism that moves the cap 91 so as to be detachable from the ink heads 40 to 70. In the present embodiment, the cap moving mechanism 92 moves the cap 91 in the vertical direction. The configuration of the cap moving mechanism 92 is not particularly limited, but includes, for example, a drive motor 92a. The cap moving mechanism 92 moves the cap 91 in the vertical direction by driving the drive motor 92a. The cap 91 is attached to the ink heads 40 to 70 and moved away from the ink heads 40 to 70 by moving in the vertical direction.

  The suction pump 93 is a member that sucks ink in the ink heads 40 to 70 in a state where the cap 91 is attached to the ink heads 40 to 70. The suction is an operation for eliminating the ejection failure of the nozzles 41 to 71 and an operation for preventing the nozzles 41 to 71 from being clogged. The suction port of the suction pump 93 is connected to the cap 91. The discharge port of the suction pump 93 is connected to a waste liquid tank (not shown). The ink sucked by the suction pump 93 is discharged to the waste liquid tank.

  A wiper 95 may be provided on the left side of the capping device 90. The wiper 95 is a member that wipes the lower surfaces of the ink heads 40 to 70. The wiper 95 is disposed below the guide rail 20. The wiper 95 is configured to contact the lower surfaces of the ink heads 40 to 70 when the carriage 30 passes over the wiper 95. The wiper 95 is a plate-like member and is formed of, for example, rubber.

  FIG. 4 is a block diagram of the printing system 100. As shown in FIG. 4, the printer 10 includes a print control device 110. The print control device 110 is a device that controls printing on the recording medium 5. The configuration of the print control apparatus 110 is not particularly limited. The print control apparatus 110 is a microcomputer, for example. The configuration of the hardware of the microcomputer is not particularly limited. For example, an interface (I / F) that receives print data from an external device such as a host computer, and a central processing unit (CPU: CPU) that executes control program instructions. a central processing unit), a ROM (read only memory) that stores a program executed by the CPU, a RAM (random access memory) that is used as a working area for developing the program, and a memory that stores programs and various data. And a storage device. As shown in FIG. 1, the print control apparatus 110 is provided in the printer main body 10a. However, the print control apparatus 110 may not be provided in the printer main body 10a. For example, the print control apparatus 110 may be a computer installed outside the printer main body 10a. In this case, the print control apparatus 110 is communicably connected to the printer main body 10a via a wired or wireless connection.

  In the present embodiment, as illustrated in FIG. 4, the print control apparatus 110 includes an operation panel 12, a carriage motor 24 of the head moving mechanism 31, a feed motor 27 of the medium transport mechanism 32, ink heads 40 to 70, The drive motor 92a of the capping device 90 and the suction pump 93 are communicably connected. The print control device 110 controls the operation panel 12, the carriage motor 24, the feed motor 27, the ink heads 40 to 70, the drive motor 92a, and the suction pump 93. The print control device 110 controls the driving of the carriage motor 24 of the head moving mechanism 31 to control the rotation of the pulley 22 and the traveling of the belt 23 (see FIG. 1). Thus, the print control apparatus 110 controls the movement of the ink heads 40 to 70 in the main scanning direction Y. The printing control device 110 controls the rotation of the grit roller 25 by controlling the drive of the feed motor 27 of the medium transport mechanism 32, thereby moving the recording medium 5 placed on the platen 16 in the sub-scanning direction X. Control. The print control device 110 controls the timing at which the ink heads 40 to 70 eject ink. The print control device 110 controls the movement of the cap 91 in the vertical direction by controlling the drive of the drive motor 92a of the capping device 90. Further, the print control device 110 controls the timing at which the suction pump 93 sucks ink in the ink heads 40 to 70 and the like.

  In the present embodiment, the print control apparatus 110 includes a printing side storage unit 112, a normal printing unit 114, a check pattern printing unit 116, and a cleaning control unit 118. Each part mentioned above may be constituted by software, and may be constituted by hardware. For example, each unit described above may be performed by a processor.

  The normal printing unit 114 controls the printing operation. The normal printing unit 114 performs so-called normal image printing. The normal printing unit 114 prints an image on the recording medium 5 based on image data stored in advance in the printing-side storage unit 112 or image data specified by an external computer or the like. Specifically, the normal printing unit 114 controls the head moving mechanism 31 so as to move the carriage 30 in the main scanning direction Y, and ejects ink from each of the ink heads 40 to 70 to record on the platen 16. Ink is landed on the medium 5. Further, the normal printing unit 114 controls the medium transport mechanism 32 so that the recording medium 5 is sequentially transported forward. As described above, normal printing is performed by the normal printing unit 114.

  FIG. 5 is a schematic diagram illustrating an example of the check pattern P1. In FIG. 5, the ink heads 40 to 70 in plan view are shown on the left side of the check pattern P1. In FIG. 5, the ink heads 40 to 70 and the nozzles 41 to 71 are shown by solid lines in consideration of easy viewing. In FIG. 5, the number of the nozzles 41 to 71 included in each of the ink heads 40 to 70 is set to 10 for simplification of description. The check pattern printing unit 116 prints the check pattern P1 (see FIG. 5) on the recording medium 5. Here, the check pattern P1 is an inspection image for confirming the discharge state of each nozzle 41 to 71 of each ink head 40 to 70. For example, when there are nozzles 41 to 71 in which ink ejection failure occurs, a pattern is lost at a position on the check pattern P1 where the nozzle should eject ink. Here, the missing pattern is also referred to as nozzle missing. In addition, when there are nozzles 41 to 71 that eject ink but cannot eject ink normally, problems such as pattern displacement occur. The user can know that there are defective nozzles 41 to 71 due to the lack of the pattern. The check pattern P1 is printed by moving the ink heads 40 to 70 in the main scanning direction Y. A check for ejection failure of the nozzles 41 to 71 by the check pattern P1 is performed, for example, at a start-up inspection.

  The configuration of the check pattern P1 is not particularly limited. As shown in FIG. 5, in this embodiment, the check pattern P1 has four pattern rows PM, PY, PC, and PK. Hereinafter, the pattern rows PM, PY, PC, and PK are appropriately described as pattern rows PM to PK. The number of pattern rows PM, PY, PC, PK corresponds to the number of ink heads 40-70. The pattern row PM is formed by ink dots of magenta ink ejected from the ink head 40. The pattern row PY is formed by yellow ink ink dots ejected from the ink head 50. The pattern row PC is formed by ink dots of cyan ink ejected from the ink head 60. The pattern row PK is formed by black ink dots of the ink head 70. In the present embodiment, the pattern rows PM to PK are arranged in the main scanning direction Y in the order of PM, PY, PC, and PK from the left side. The arrangement order of the pattern rows PM to PK in the main scanning direction Y is the same as the arrangement order of the ink heads 40 to 70 in the main scanning direction Y.

  In the present embodiment, the pattern rows PM to PK have the same configuration. Therefore, here, the configuration of the pattern sequence PM will be described, and the description regarding the configuration of the pattern sequences PY, PC, and PK will be omitted. In the present embodiment, the pattern row PM is composed of ten print lines L1 to L10. The print lines L1 to L10 are arranged in a line in the sub-scanning direction X. Each of the printing lines L1 to L10 is formed by ink dots ejected from the nozzles 41a to 41j of the ink head 40, respectively. For example, the print line L1 is formed by magenta ink ejected from the nozzle 41a. The print line L2 is formed by magenta ink ejected from the nozzle 41b. The print line L10 is formed by magenta ink ejected from the nozzle 41j. The same applies to the other pattern rows PY, PC, and PK. Thus, in this embodiment, the pattern row PM is configured by the same number of print lines L1 to L10 as the number of nozzles 41 of the ink head 40.

  The print lines L1 to L10 of the check pattern P1 are printed when the ink heads 40 to 70 move in one direction of the main scanning direction Y. That is, when the check pattern P1 is printed on the recording medium 5, the recording medium 5 does not move. Therefore, in the pattern row PM, the print lines L1 to L10 are printed at the same pitch as the pitch of the nozzle 41 in the sub-scanning direction X. In FIG. 5, only 10 nozzles 41 are illustrated, but actually, for example, 180 nozzles. The actual pitch of the nozzle 41 in the sub-scanning direction X is, for example, 180 dpi.

  The configuration of the check pattern P1 is not limited to the configuration of FIG. For example, the check pattern P1 may be configured such that a print line constituted by ink of one ink head is divided into a plurality of pattern rows. For example, taking the ink head 40 as an example, the configuration of the check pattern P1 is as follows. For example, when all the print lines L1 to L10 of the nozzles 41 of the ink head 40 are arranged in two pattern rows (a first pattern row and a second pattern row), the first pattern row includes print lines. Of L1 to L10, odd-numbered print lines L1, L3, L5, L7, and L9 are assigned. Printing lines L1, L3, L5, L7, and L9 formed by the nozzles 41a, 41c, 41e, 41g, and 41i are distributed to the first pattern row. On the other hand, even-numbered print lines L2, L4, L6, L8, and L10 are distributed to the second pattern row. Printing lines L2, L4, L6, L8, and L10 formed by the nozzles 41b, 41d, 41f, 41h, and 41j are distributed to the second pattern row. As described above, by assigning the print lines L1 to L10 related to the nozzle 41 to a plurality of pattern rows, the interval between the print lines arranged in the same pattern row becomes wide, and the check pattern P1 becomes easy to see. Further, at the actual pitch of the nozzles 41 to 71, when all the print lines related to the nozzles of the ink heads 40 to 70 are arranged in one pattern row, the print lines may overlap each other. In such a case, a method for distributing print lines as described above is used. In the above description, the print lines related to the nozzles of the ink heads 40 to 70 are distributed into two pattern rows, but may be distributed into three or more pattern rows. The number of pattern rows for distributing print lines is not limited. As described above, in the present embodiment, the check pattern printing unit 116 uses the ink ejected from the nozzles 41 to 71 of the ink heads 40 to 70 to print the print lines L1 to P1, PY, PC, and PK. By forming L10, the check pattern P1 is printed on the recording medium 5.

  After the check pattern P1 is printed on the recording medium 5 by the check pattern printing unit 116, the user visually checks the check pattern P1 printed on the recording medium 5 to confirm the presence or absence of ejection defects such as missing nozzles. Here, for example, it is assumed that the nozzle 41d is clogged and ink cannot be ejected. In this case, at least a part of the print line L4 corresponding to the nozzle 41d is missing. The user discovers that a discharge failure has occurred in the nozzle 41d by visually observing the absence of the print line L4. When the user finds a nozzle ejection failure, cleaning is performed by the cleaning control unit 118. For example, the operation panel 12 is provided with a cleaning button (not shown), and when the user presses the cleaning button, cleaning control by the cleaning control unit 118 is started.

  The cleaning control unit 118 controls the cleaning operation for the nozzles 41 to 71 of the ink heads 40 to 70. Here, the “cleaning operation” is an operation performed on the ink heads 40 to 70 at the home position HP (see FIG. 3) during printing standby. The cleaning operation is an operation performed when, for example, a discharge failure occurs in the nozzles 41 to 71 of the ink heads 40 to 70. Here, as the cleaning operation, an operation for forcibly ejecting ink into the cap 91 (see FIG. 3) is performed by the ink heads 40 to 70. Specifically, the cleaning control unit 118 sucks ink by the suction pump 93 (see FIG. 3) while discharging ink from the nozzles 41 to 71. As a result, the solidified ink in the ink heads 40 to 70 is removed from the nozzles 41 to 71, thereby eliminating the ejection failure.

  By the way, when the user visually checks the check pattern P1 printed on the recording medium 5 and finds a discharge failure of the nozzles 41 to 71, how long the cleaning time (hereinafter referred to as the cleaning time) is set. Was determined by the user's rule of thumb. Therefore, since the cleaning time is short, even after the cleaning is performed, the ejection failure of the nozzles 41 to 71 may not be solved. Further, since the cleaning time is too long, cleaning may be performed for a longer time than necessary.

  Therefore, the applicant of the present application examined a method for setting an optimum cleaning time. As a result, the applicant of the present application has found that the required cleaning time varies depending on the degree of ejection failure of the nozzles 41 to 71. Hereinafter, the degree of the ejection failure state of the nozzles 41 to 71 is appropriately referred to as a “defective state”.

  6A to 6G are schematic diagrams of a check pattern P1 indicating a defective state. Specifically, FIGS. 6A to 6G are schematic diagrams of the check pattern P1 showing the first defect state S1 to the seventh defect state S7, respectively. In the present embodiment, the first defect state S1, the second defect state S2, the third defect state S3, the fourth defect state S4, the fifth defect state S5, the sixth defect state S6, and the seventh defect are the defect states. State S7 is defined. However, the number of states defined as defective states is not particularly limited, and may be, for example, 6 or less, or 8 or more. Hereinafter, the first defective state S1 to the seventh defective state S7 of the nozzle 41b will be described on the assumption that a discharge failure has occurred in the nozzle 41b of the ink head 40. In the present embodiment, the shape of the print line L2 in FIG. 5 is a reference shape, and the position of the print line L2 in FIG. 5 is a reference position.

  In the present embodiment, as shown in FIG. 6A, the first defective state S1 refers to a state in which the printing line L2 is missing one dot compared to the reference shape. The first defective state S1 is a state in which one dot of ink dots constituting the printing line L2 is missing. In the first defect state S1, the position of the print line L2 is the reference position. As shown in FIG. 6B, the second defective state S2 refers to a state in which the printing line L2 is missing two dots compared to the reference shape. The second defective state S2 is a state in which two ink dots constituting the printing line L2 are missing. In the second defect state S2, the position of the print line L2 is a reference position. As shown in FIG. 6C, the third defect state S3 refers to a state in which the print line L2 is missing 3 dots or more compared to the reference shape. FIG. 6C shows a state where all of the ink dots constituting the print line L2 are missing as an example of the third defect state S3. Thus, when all the ink dots are missing, the nozzle 41b from which the ink forming the print line L2 is ejected is clogged, and no ink is ejected from the nozzle 41b. In the third defect state S3, the position of the print line L2 is a reference position.

  As shown in FIG. 6D, the fourth defect state S4 refers to a state in which the print line L2 is displaced in the sub-scanning direction X as compared with the reference position. The fourth defective state S4 is a state in which the print line L2 is shifted in the sub-scanning direction X with respect to other print lines (for example, the print lines L1 and L3). In the fourth defect state S4, the print line L2 may be shifted rearward (here, the print line L1 side) in the sub-scanning direction X as compared to the reference position, or forward (here, the print line L3 side). It may be shifted. In the fourth defect state S4, the print line L2 is not shifted in the main scanning direction Y compared to the reference position. As shown in FIG. 6E, the fifth defect state S5 refers to a state in which the print line L2 is displaced in the main scanning direction Y compared to the reference position. The fifth defective state S5 is a state in which the print line L2 is shifted in the main scanning direction Y with respect to the other print lines. In the fifth defect state S5, the print line L2 may be shifted to the left in the main scanning direction Y or may be shifted to the right as compared with the reference position. In the fifth defect state S5, the print line L2 is not shifted in the sub-scanning direction X compared to the reference position.

  As shown in FIG. 6F, the sixth defect state S6 refers to a state in which the print line L2 is shifted in the main scanning direction Y and the sub-scanning direction X compared to the reference position. The sixth defective state S6 is a state in which the print line L2 is shifted in the main scanning direction Y with respect to the other print lines and is shifted in the sub-scanning direction X. In the sixth defect state S6, the print line L2 may be shifted to the left in the main scanning direction Y or may be shifted to the right as compared with the reference position. In the sixth defect state S6, the print line L2 may be shifted rearward in the sub-scanning direction X or forward compared to the reference position. As illustrated in FIG. 6G, the seventh defective state S7 refers to a state in which the print line L2 is obliquely displaced as compared to the reference position. The seventh defective state S7 is a state in which the print line L2 is obliquely displaced with respect to the other print lines. In the example of FIG. 6G, in the seventh defect state S7, the left end of the print line L2 is shifted to the print line L1 side, and the right end of the print line L2 is shifted to the print line L3 side.

  In the fourth defect state S4 to the seventh defect state S7, the shape of the print line L2 is not particularly limited. For example, as illustrated in FIGS. 6D to 6G, in the fourth defect state S4 to the seventh defect state S7, the shape of the print line L2 may be a reference shape. Further, in the fourth defect state S4 to the seventh defect state S7, the shape of the print line L2 may be a shape in which some ink dots are missing.

  In the present embodiment, among the first failure state S1 to the seventh failure state S7, the first failure state S1 is a mild discharge failure state, and the second failure state S2 is the second lightest discharge failure state. is there. The seventh defective state S7 is the most severe discharge failure state, and the third defective state S3 to the sixth defective state S6 are the second most severe discharge failure states. The more serious the ejection failure, the longer the cleaning time. For this reason, in the check pattern P1 printed on the recording medium 5, when a highly serious failure state (for example, the seventh failure state S7) is found, the cleaning time may be set longer.

  Further, the applicant of the present application depends on the printing standby time (hereinafter referred to as standby time) and the frequency of occurrence of ejection failure in each of the nozzles 41 to 71 (hereinafter referred to as failure frequency). I found. Here, the standby time is a continuous time during which printing is not performed. The waiting time refers to a continuous time in which the carriage 30 and the ink heads 40 to 70 are waiting at the home position HP (see FIG. 3). The longer this waiting time, the longer the time during which ink is not ejected from the nozzles 41 to 71, and the longer the time that ink remains in the ink heads 40 to 70. Therefore, there is a possibility that the ink in the ink heads 40 to 70 is solidified and the nozzles 41 to 71 are clogged. Thus, when the standby time is long, the cleaning time may be set longer. On the other hand, when the waiting time is short, the cleaning time may be set short.

  The defect frequency is a frequency at which a discharge defect occurs in each of the nozzles 41 to 71. For example, the failure frequency is represented by the number of ejection failures occurring in a predetermined time in each of the nozzles 41 to 71. Although the specific time of this predetermined time is not specifically limited, For example, it is 10 to 30 days. When ejection failures occur in the nozzles 41 to 71 having a high failure frequency, it can be said that ejection failures frequently occur in the nozzles 41 to 71. In this case, the cleaning time may be set longer. On the other hand, when a discharge failure has occurred in the nozzles 41 to 71 having a low failure frequency, it can be said that the nozzles 41 to 71 have not had many discharge failures in the past. In this case, the cleaning time may be set short. This defect frequency is set for each nozzle 41 to 71 of each ink head 40 to 70.

  As described above, when the ejection failure of the nozzles 41 to 71 is found in the check pattern P1, the cleaning time may be set based on the failure state, the standby time, and the failure frequency. Here, the present applicant has further found that the feature amount is calculated based on the defect state, the standby time, and the defect frequency. This feature amount serves as an index for predicting the cleaning time. The present applicant has found that an optimal cleaning time can be predicted based on the calculated feature amount.

  In the present embodiment, the feature amount for predicting the optimum cleaning time is calculated using a failure state coefficient, a standby time coefficient, and a failure frequency coefficient. Here, the defect state coefficient is a numerical value of the degree of the discharge defect state of the nozzles 41 to 71 based on the check pattern P1. Here, the defect state coefficient is a weight coefficient corresponding to the first defect state S1 to the seventh defect state S7 and is a preset weight coefficient. FIG. 7 is a diagram illustrating the defect state coefficient table T1. In the present embodiment, the failure state and the failure state coefficient are associated by the failure state coefficient table T1 as shown in FIG. For example, in the case of the first failure state S1, the failure state coefficient is “1”. In the case of the second failure state S2, the failure state coefficient is “2”. In any of the third failure state S3 to the sixth failure state S6, the failure state coefficient is “3”. In the case of the seventh failure state S7, the failure state coefficient is “4”. However, the specific numerical value of the defect state coefficient for each defect state is not particularly limited. For example, a different defect state coefficient may be set in each defect state. In the present embodiment, the failure state coefficient “1” corresponds to the first failure state coefficient of the present invention, and the failure state coefficient “2” corresponds to the second failure state coefficient of the present invention. In the present embodiment, the failure state coefficient “3” corresponds to the third failure state coefficient of the present invention, and the failure state coefficient “4” corresponds to the fourth failure state coefficient of the present invention.

The standby time coefficient is a coefficient based on the standby time. For example, when the standby time is t, the standby time coefficient D2 can be calculated using the following equation (1). However, the specific formula for calculating the standby time coefficient D2 is not limited to the following formula (1). The unit of the standby time t is not particularly limited, but is, for example, seconds.

The defect frequency coefficient is a coefficient based on the defect frequency. For example, when the failure frequency is n and the predetermined constant is α, the failure frequency coefficient D3 can be calculated using the following equation (2). However, the specific formula for calculating the failure frequency coefficient D3 is not limited to the following formula (2).
D3 = exp (αn) (2)

  The unit of the defect frequency n is not particularly limited, but is, for example, the number of times in a predetermined time (for example, 10 days). The constant α is for adjusting the value of the exponential function, and is appropriately set according to the unit of the failure frequency n. For example, the constant α is 0.1.

In the present embodiment, the feature amount F for predicting the optimum cleaning time is calculated using the following equation (3). Here, D1 indicates a defect state coefficient. D2 represents a standby time coefficient. D3 indicates a failure frequency coefficient. The specific formula for calculating the feature amount F is not limited to the following formula (3).
F = D1 × D2 × D3 (3)

  In the present embodiment, the cleaning time prediction device 130 (see FIG. 4) predicts the cleaning time using the feature amount F calculated by the defect state coefficient D1, the standby time coefficient D2, and the defect frequency coefficient D3. Do. Next, the cleaning time predicting device 130 will be described. As shown in FIG. 4, the printing system 100 includes a cleaning time prediction device 130. The cleaning time predicting device 130 is a device that predicts the time required for cleaning when ejection failure of the nozzles 41 to 71 of the ink heads 40 to 70 occurs. The cleaning time predicted by the cleaning time prediction device 130 is a time during which ejection defects of the nozzles 41 to 71 can be resolved. The configuration of the cleaning time prediction device 130 is not particularly limited. In the present embodiment, the cleaning time prediction device 130 is realized by a computer installed outside the printer body 10 a of the printer 10. However, the cleaning time prediction device 130 may be provided inside the printer main body 10a. In the present embodiment, the cleaning time prediction device 130 includes a display screen 131, an operation unit 132, and a control device 140.

  The display screen 131 displays information regarding the cleaning time. The specific type of display screen 131 is not particularly limited. For example, the display screen 131 is a computer display. However, the display screen 131 may be provided on the operation panel 12 (see FIG. 1). For example, the display screen 131 may be a display unit of the operation panel 12.

  The operation unit 132 is used by the user to input or specify information regarding the cleaning time. The specific type of the operation unit 132 is not particularly limited. For example, the operation unit 132 is a computer keyboard and mouse. However, the operation unit 132 may be a touch panel provided on the display screen 131. The operation unit 132 may be provided on the operation panel 12. For example, the operation unit 132 may be an input unit of the operation panel 12.

  In the present embodiment, the control device 140 calculates a cleaning time. The configuration of the control device 140 is not particularly limited. The control device 140 is, for example, a microcomputer. The hardware configuration of the microcomputer is not particularly limited. For example, the microcomputer includes an interface (I / F) that receives print data from an external device such as a host computer, a CPU, a ROM, a RAM, and a storage device. ing.

  The control device 140 is communicably connected to the print control device 110 via wired or wireless communication. The control device 140 is connected to the display screen 131 and the operation unit 132 so as to communicate with each other.

  In the present embodiment, the control device 140 includes a storage unit 142, an image storage unit 144, a defect state coefficient determination unit 146, a standby time coefficient determination unit 148, a defect frequency coefficient determination unit 150, and a predicted feature amount calculation unit. 152, a cleaning time prediction unit 154, a cleaning time transmission unit 156, a determination unit 158, an addition unit 160, and a re-cleaning designation unit 162. In addition, each said part may be comprised by software and may be comprised by hardware. For example, each unit described above may be performed by a processor, or may be incorporated in a circuit.

  In the present embodiment, the printing system 100 includes a photographing device 135. The photographing device 135 photographs a printed matter on the recording medium 5 placed on the platen 16 (see FIG. 1). Here, the imaging device 135 images the check pattern P1 printed on the recording medium 5. In addition, the kind of imaging device 135 is not specifically limited. For example, the photographing device 135 is a camera. Further, the arrangement position of the photographing device 135 is not particularly limited. For example, the photographing device 135 may be attached to the printer main body 10 a so as to be positioned above the platen 16. The photographing device 135 may be provided separately from the printer main body 10a. In the present embodiment, the imaging device 135 is connected to the print control device 110 and the control device 140 so as to be communicable. The photographing device 135 automatically performs photographing under the control of the control device 140. However, the photographing device 135 may be a device that performs photographing when a user presses a photographing button (not shown).

  Next, a procedure in which the cleaning time prediction device 130 predicts the cleaning time and performs the cleaning with the predicted cleaning time will be described with reference to the flowchart of FIG. In the present embodiment, prior to predicting the cleaning time, the storage unit 142 stores in advance a standby time t, a failure frequency n, a failure state coefficient table T1, and a feature amount table T2.

  As described above, the standby time t is a continuous time during which printing by the printer 10 is not performed. Specifically, the standby time t is a time period from when printing such as normal printing by the printer 10 or printing of the check pattern P1 is completed until printing of the next check pattern P1 is started. The failure frequency n is the number of times that a discharge failure has occurred in each of the nozzles 41 to 71 during a predetermined time. That is, in this embodiment, the defect frequency n is set for each of the nozzles 41 to 71. The predetermined time is stored in advance in the storage unit 142. The defect state coefficient table T1 is a defect state coefficient table as shown in FIG. 7, for example.

  FIG. 9 is a diagram illustrating an example of the feature amount table T2. As shown in FIG. 9, the feature amount table T2 is a table in which the actual feature amount is associated with the actual cleaning time. Here, the actual cleaning time is a cleaning time performed in the past, and is a cleaning time in which the ejection failure of the nozzles 41 to 71 is eliminated by one cleaning. The actual feature amount is an actual feature amount corresponding to the actual cleaning time. In the example of FIG. 9, for example, the actual cleaning time when the actual feature amount is “1” is 30 seconds. For example, the actual cleaning time when the actual feature amount is “10” is 150 seconds.

  In this embodiment, when the cleaning time is predicted, first, in step S101 in FIG. 8, the check pattern P1 is printed. In the present embodiment, for example, the operation unit 132 is provided with a check pattern print button (not shown). When the user presses the check pattern print button, the control device 140 of the cleaning time prediction device 130 transmits a check pattern print start signal to the print control device 110. After the print control apparatus 110 receives the check pattern printing start signal, the check pattern printing unit 116 prints the check pattern P1 as shown in FIG. 5 on the recording medium 5 placed on the platen 16. Specifically, the check pattern printing unit 116 controls the head moving mechanism 31 so that the ink heads 40 to 70 move from the right to the left in the main scanning direction Y, and the nozzles 41 of the ink heads 40 to 70. By ejecting ink from ˜71, the printing lines L1 to L10 of the pattern rows PM, PY, PC, and PK are printed on the recording medium 5, as shown in FIG.

  Next, in step S <b> 103 of FIG. 8, the check pattern P <b> 1 printed on the recording medium 5 is photographed using the photographing device 135. In the present embodiment, a photographing signal is transmitted from the control device 140 to the photographing device 135. Then, the imaging device 135 that has received the imaging signal images the check pattern P1 printed on the recording medium 5. Note that the image of the check pattern P <b> 1 photographed by the photographing device 135 is stored in the storage unit 142 by the image storage unit 144.

  Next, in step S105 in FIG. 8, a failure state coefficient D1, a standby time coefficient D2, and a failure frequency coefficient D3 are determined. Here, the defect condition coefficient determination unit 146 has the print lines L1 to L10 based on the check pattern P1 stored in the storage unit 142 by the image storage unit 144, and the first defect states S1 to S7 in FIGS. 6A to 6G. The failure state of the failure state S7 is analyzed. This failure state analysis method is performed, for example, by image processing. However, the determination of the defective state may be performed by the user. For example, the user may input which defective state the print lines L1 to L10 by operating the operation unit 132. Here, the failure state with higher severity is preferentially determined. For example, when the shape of the print line L2 is a one-dot missing shape as shown in FIG. 6A and the position of the print line L2 is shifted in the main scanning direction Y as shown in FIG. A high fifth failure state S5 is employed. In the present embodiment, the failure state coefficient determination unit 146 determines a failure state coefficient D1 corresponding to the determined failure state using a failure state coefficient table T1 as shown in FIG. For example, when the failure state is determined to be the first failure state S1 (see FIG. 6A), the failure state coefficient determination unit 146 determines “1” as the failure state coefficient D1.

  The standby time coefficient determination unit 148 determines the standby time coefficient D2 based on the standby time t stored in the storage unit 142. In the present embodiment, the standby time coefficient determination unit 148 calculates the standby time coefficient D2 using the above-described equation (1). The failure frequency coefficient determination unit 150 determines the failure frequency coefficient D3 based on the failure frequency n stored in the storage unit 142. In the present embodiment, the failure frequency coefficient determination unit 150 calculates the failure frequency coefficient D3 using the above-described equation (2). As described above, the defect state coefficient D1, the standby time coefficient D2, and the defect frequency coefficient D3 are determined.

  Next, in step S107 in FIG. 8, a predicted feature amount F is calculated. Here, the predicted feature amount F is a feature amount calculated based on the defect state coefficient D1, the standby time coefficient D2, and the defect frequency coefficient D3. In the present embodiment, the predicted feature amount calculation unit 152 calculates the predicted feature amount F based on the failure state coefficient D1, the standby time coefficient D2, and the failure frequency coefficient D3. Specifically, the predicted feature value calculation unit 152 calculates the predicted feature value F using the above-described equation (3).

  Next, in step S109 of FIG. 8, a cleaning time estimated to eliminate the ejection failure of the nozzles 41 to 71 is predicted. Here, the cleaning time predicted in step S109 is referred to as predicted cleaning time. In the present embodiment, the cleaning time prediction unit 154 determines the predicted cleaning time using the predicted feature amount F calculated by the predicted feature amount calculation unit 152 and the feature amount table T2 of FIG.

  Specifically, the cleaning time prediction unit 154 first estimates the cleaning time corresponding to each feature amount based on the feature amount table T2. The estimated cleaning time is referred to as estimated cleaning time. The method for estimating the estimated cleaning time is not particularly limited, and a conventionally known method can be used. In this embodiment, the estimated cleaning time is estimated using a Gaussian process. As described above, the estimated cleaning time is estimated by the cleaning time predicting unit 154, whereby the estimated cleaning time corresponding to each feature amount is obtained as shown in the graph of FIG. Here, the feature amount in FIG. 10 is also referred to as an estimated feature amount. The estimated feature amount includes a feature amount other than the actual feature amount of the feature amount table T2. The cleaning time prediction unit 154 determines an estimated cleaning time corresponding to the predicted feature amount F calculated by the predicted feature amount calculation unit 152 from a graph or the like as shown in FIG. The estimated cleaning time obtained in this way is set as the estimated cleaning time. As described above, in the present embodiment, the cleaning time predicting unit 154 predicts the predicted cleaning time corresponding to the predicted feature amount F using the Gaussian process with reference to the feature amount table T2.

  Next, in step S111 in FIG. 8, cleaning is performed based on the predicted cleaning time. Here, first, the cleaning time transmission unit 156 transmits the predicted cleaning time to the print control apparatus 110 of the printer 10. Then, after the print control apparatus 110 receives the estimated cleaning time, the cleaning control unit 118 performs control so that the ink heads 40 to 70 are cleaned during the estimated cleaning time. In the present embodiment, as shown in FIG. 3, in a state where the cap 91 is attached to the ink heads 40 to 70, the cleaning control unit 118 uses the suction pump 93 while discharging ink from the nozzles 41 to 71. Ink the ink.

  After the cleaning in step S111 in FIG. 8 is completed, it is next determined in step S113 in FIG. 8 whether or not the ejection defects of the nozzles 41 to 71 have been resolved. Here, first, the check pattern P1 is printed on the recording medium 5 again. The check pattern printing unit 116 prints the check pattern P1 on the recording medium 5 placed on the platen 16. Thereafter, as in step S103, the check pattern P1 printed on the recording medium 5 is photographed using the photographing device 135. In the present embodiment, after the imaging signal is transmitted from the control device 140 to the imaging device 135, the imaging device 135 images the check pattern P <b> 1 printed on the recording medium 5. Then, the image storage unit 144 stores the image of the check pattern P1 captured by the imaging device 135 in the storage unit 142.

  Thereafter, the determination unit 158 determines whether or not the ejection failure of the nozzles 41 to 71 has been resolved. At this time, the determination unit 158 determines which of the first defect state S1 to the seventh defect state S7 in FIGS. 6A to 6G the check pattern P1 stored in the storage unit 142 by the image storage unit 144 is. For example, analysis is performed using image processing. When it is analyzed that none of the first failure state S1 to the seventh failure state S7 appears in the check pattern P1, the determination unit 158 determines that the ejection failure of the nozzles 41 to 71 has been eliminated. To do. Thereafter, the process proceeds to step S115 in FIG.

  In step S115, the addition unit 160 associates and adds the predicted feature amount F calculated by the predicted feature amount calculation unit 152 and the predicted cleaning time predicted by the cleaning time prediction unit 154 to the feature amount table T2. In the present embodiment, the display screen 131 displays a message indicating that the predicted feature amount F and the predicted cleaning time are to be added. The operation unit 132 is provided with an add button (not shown). When the user presses the add button, the adder 160 adds the predicted feature amount F and the predicted cleaning time to the feature amount table T2. It may be configured to add. As described above, in the present embodiment, in the feature amount table T2, the predicted cleaning time when the ejection failure of the nozzles 41 to 71 is eliminated and the predicted feature amount corresponding to the predicted cleaning time are sequentially accumulated.

  In step S113, when it is analyzed that any one of the first failure state S1 to the seventh failure state S7 appears in the check pattern P1, the determination unit 158 eliminates the discharge failure of the nozzles 41 to 71. Judge that it is not. In this case, the process proceeds to step S117. In step S117, cleaning is performed again. The cleaning time at this time is not particularly limited. For example, the cleaning time performed in step S117 may be the predicted cleaning time predicted based on the defective state appearing in the check pattern P1, as in step S113. Note that the predicted cleaning time in step S117 is referred to as a re-estimated cleaning time. In step S <b> 117, first, the re-cleaning designation unit 162 transmits a re-cleaning signal that is a signal for performing cleaning again and a re-estimated cleaning time to the print control apparatus 110. Then, after the print control device 110 receives the re-cleaning signal, the cleaning control unit 118 cleans the ink heads 40 to 70 during the re-estimated cleaning time. Since the cleaning at this time is the same as the cleaning in step S111, description thereof is omitted. In addition, after cleaning is actually performed again in step S117, the process proceeds to step S113 again.

  As described above, in the present embodiment, the necessary cleaning time varies depending on the ejection failure state of the nozzles 41 to 71. Further, it can be said that the longer the waiting time t, the more the ink is solidified, and the longer the cleaning time. It can be said that the higher the defect frequency n, the easier the ejection failure of the nozzles 41 to 71 and the longer the cleaning time. Therefore, in the present embodiment, the predicted feature amount F used when predicting the cleaning time is based on the defect state coefficient D1, the standby time coefficient D2, and the defect frequency coefficient D3, which are coefficients that affect the cleaning time. Is calculated. Then, the predicted cleaning time corresponding to the predicted feature amount F is determined using the feature amount table T2 showing the relationship between the actual cleaning time actually performed and the actual feature amount. Thus, by predicting the cleaning time based on a coefficient that is likely to affect the cleaning time, an appropriate cleaning time can be predicted. Further, since the predicted cleaning time corresponding to the predicted feature amount F is predicted using the feature amount table T2 showing the relationship between the actual cleaning time and the feature, the ink heads 40 to 70 of the target printer 10 are used. A suitable cleaning time can be set.

  In the present embodiment, the defect states include a first defect state S1 to a seventh defect state S7 as shown in FIGS. 6A to 6G. Then, in the defect state coefficient table T1 as shown in FIG. 7, the defect states S1 to S7 and the defect state coefficient D1 are associated with each other. For example, as shown in FIG. 7, “1” is set to the failure state coefficient D1 of the first failure state S1, and “2” is set to the failure state coefficient D1 of the second failure state S2. . Further, “3” is set in the defect state coefficient D1 of the third defect state S3 to the sixth defect state S6, and “4” is set in the defect state coefficient D1 of the seventh defect state S7. The defect state coefficient determination unit 146 determines which defect state is the defect state of the check pattern P1 (see FIG. 5) printed by the printer 10, and displays the defect state coefficient D1 corresponding to the determined defect state. This is determined by referring to the defect state coefficient table T1 as shown in FIG. As described above, when there is a deviation between the position of the print line of the check pattern P1 and the reference position, the time required for cleaning tends to be longer. Therefore, when there is a deviation, a larger defect state coefficient is set. Therefore, it is possible to predict the predicted cleaning time according to each of the defective states S1 to S7. In the present embodiment, the defect state coefficients for the respective defect states S1 to S7 are clearly defined by the defect state coefficient table T1. Therefore, the defect state coefficient can be easily determined by using the defect state coefficient table T1.

  In the present embodiment, the standby time coefficient determination unit 148 calculates the standby time coefficient D2 based on the standby time t using the above equation (1). This makes it possible to determine the standby time coefficient D2 that matches the standby time t. Therefore, it is possible to determine the predicted cleaning time in consideration of the standby time t.

  In the present embodiment, the failure frequency coefficient determination unit 150 calculates the failure frequency coefficient D3 based on the failure frequency n using the above equation (2). This makes it possible to determine the failure frequency coefficient D3 in accordance with the failure frequency n. Therefore, the predicted cleaning time in consideration of the defect frequency n can be determined.

  In the present embodiment, the predicted feature value calculation unit 152 multiplies the failure state coefficient D1, the standby time coefficient D2, and the failure frequency coefficient D3 as shown in the above equation (3), thereby calculating the predicted feature value F. Calculated. Thus, the predicted cleaning time can be determined using the predicted feature amount F that reflects any of the defect state coefficient D1, the standby time coefficient D2, and the defect frequency coefficient D3. Therefore, the predicted cleaning time is determined in consideration of the defective state, the standby time t, and the defective frequency n, so that a more appropriate cleaning time can be predicted.

  In the present embodiment, the cleaning time prediction unit 154 refers to the predicted feature amount F and the feature amount table T2 (see FIG. 9), and predicts the cleaning time using a Gaussian process. Here, by using a Gaussian process, the estimated cleaning time corresponding to each estimated feature value is estimated from each data of the feature value table T2, as shown in FIG. This makes it possible to estimate the cleaning time corresponding to a feature quantity that does not exist in the feature quantity table T2 (for example, the feature quantity is “9” in FIG. 9). Therefore, even when a feature quantity that does not exist in the feature quantity table T2 is calculated as the predicted feature quantity F, the cleaning time can be predicted.

  In the present embodiment, the check pattern P1 printed by the check pattern printing unit 116 is photographed by the photographing device 135 (see FIG. 4). Then, the image of the check pattern P <b> 1 photographed by the photographing device 135 is stored in the storage unit 142 by the image storage unit 144. Accordingly, the defect state coefficient determination unit 146 uses the image processing based on the image of the check pattern P1 stored in the storage unit 142 to change the state of the check pattern P1 to the first defect states S1 to S7. It is possible to determine which state is the defective state S7. Therefore, it is possible to determine more accurately which defective state the check pattern P1 is.

  In the present embodiment, the cleaning control unit 118 controls the ink in the ink heads 40 to 70 to be sucked by the suction pump 93 during the estimated cleaning time transmitted by the cleaning time transmission unit 156, thereby causing the ink head to 40 to 70 are cleaned. As a result, the cleaning is performed during the predicted cleaning time predicted by the cleaning time prediction device 130, so that the ejection failure of the nozzles 41 to 71 is easily resolved.

  In the present embodiment, after the cleaning is performed, the check pattern P1 is printed again. The completed check pattern, which is the printed check pattern P1, is photographed by the photographing device 135. The captured image of the completion check pattern is stored in the storage unit 142 by the image storage unit 144. And the determination part 158 determines whether the discharge defect of the nozzles 41-71 was eliminated based on the completion check pattern. When it is determined that the ejection failure of the nozzles 41 to 71 has been eliminated, the adding unit 160 adds the predicted feature amount F and the predicted cleaning time to the feature amount table T2 in association with each other. As a result, the predicted feature amount F and the predicted cleaning time when the ejection failure of the nozzles 41 to 71 is actually eliminated are added to the feature amount table T2. Therefore, the predicted cleaning time can be determined based on more data. Therefore, a more appropriate cleaning time can be predicted.

  In the present embodiment, when the determination unit 158 determines that the ejection failure of the nozzles 41 to 71 has not been eliminated, the recleaning designation unit 162 sends a recleaning signal, which is a signal for performing cleaning again, to the print control apparatus 110. Send. After the print control apparatus 110 receives the re-cleaning signal, the cleaning control unit 118 controls the ink heads 40 to 70 to be cleaned. As described above, for example, even when the ejection failure of the nozzles 41 to 71 is not eliminated by one cleaning, the ejection failure of the nozzles 41 to 71 can be eliminated by repeatedly performing cleaning.

  The preferred embodiments of the present invention have been described above. However, the above-described embodiments are merely examples, and the present invention can be implemented in various other forms.

  In the above embodiment, the carriage 30 is moved in the main scanning direction Y, and the recording medium 5 placed on the platen 16 is moved in the sub-scanning direction X. However, the present invention is not limited to this. The movement of the carriage 30 and the recording medium 5 is relative, and either of them may move in the main scanning direction Y or the sub-scanning direction X. For example, the recording medium 5 may be arranged so as not to move, and the carriage 30 may be configured to be movable in both the main scanning direction Y and the sub-scanning direction X. Further, both the carriage 30 and the recording medium 5 may be configured to be movable in both directions.

  Furthermore, the technology disclosed herein can be applied to various types of inkjet printers. In addition to the so-called Roll-to-Roll type printer 10 that conveys the roll-shaped recording medium 5 shown in the above embodiment, the present invention can be similarly applied to, for example, a flat bed type ink jet printer. Further, the printer 10 is not limited to a printer that is used alone as an independent printer, and may be combined with other devices. For example, the printer 10 may be built in another device.

5 Recording medium 10 Printer (inkjet printer)
16 Platen (mounting part)
40, 50, 60, 70 Ink head 41, 51, 61, 71 Nozzle 100 Printing system 110 Print control device 130 Cleaning time prediction device 135 Imaging device 140 Control device 142 Storage unit 144 Image storage unit 146 Defective state coefficient determination unit 148 Standby Time coefficient determination unit 150 Failure frequency coefficient determination unit 152 Predicted feature amount calculation unit 154 Cleaning time prediction unit 156 Cleaning time transmission unit 158 Determination unit 160 Addition unit 162 Recleaning designation unit

Claims (12)

In an ink jet printer having an ink head having a plurality of nozzles for discharging ink and capable of printing a check pattern capable of confirming the discharge state of the nozzles, cleaning for predicting a cleaning time for eliminating the discharge failure of the nozzles A time prediction device,
Equipped with a control device,
The control device includes:
A storage unit in which a standby frequency of the ink jet printer and a failure frequency that is the number of times the discharge failure of the nozzle has occurred within a predetermined time are stored in advance,
Based on the check pattern, a failure state coefficient determination unit that determines a failure state coefficient obtained by quantifying the discharge failure state of the nozzle,
A standby time coefficient determination unit that determines a standby time coefficient that is a coefficient used to calculate a feature value that is an index for predicting a cleaning time based on the standby time;
A defect frequency coefficient determination unit that determines a defect frequency coefficient that is a coefficient used to calculate the feature amount based on the defect frequency;
A predicted feature amount calculation unit that calculates a predicted feature amount that is the feature amount based on the failure state coefficient, the standby time coefficient, and the failure frequency coefficient;
With
The storage unit stores in advance a feature amount table in which an actual cleaning time that is an actual cleaning time and an actual feature amount that is the feature amount corresponding to the actual cleaning time are associated with each other.
The control device includes a cleaning time prediction unit that predicts a cleaning time that is a cleaning time corresponding to the predicted feature amount and is estimated to eliminate the ejection failure of the nozzle based on the feature amount table. Equipped with a cleaning time prediction device. When the predicted feature amount calculation unit is F, the failure state coefficient is D1, the standby time coefficient is D2, and the failure frequency coefficient is D3,
F = D1 × D2 × D3
The cleaning prediction apparatus according to claim 1, wherein the predicted feature amount is calculated by an expression represented by: The storage unit stores in advance a failure state coefficient table that associates a plurality of failure states that are the degree of ejection failure states of the nozzles based on the check pattern and the failure state coefficients corresponding to the failure states. ,
The defect state coefficient determination unit determines which defect state is the defect state of the check pattern printed by the inkjet printer, and determines the defect state coefficient corresponding to the determined defect state as the defect. The cleaning time predicting apparatus according to claim 1, wherein the cleaning time predicting apparatus is determined by referring to a state coefficient table. The check pattern has a print line formed by a plurality of dots of ink ejected from the nozzle,
In the print line, a reference position and a reference shape as a reference are preset,
In the defective state,
A first defective state in which the printing line is in a state where one dot is missing compared to the reference shape;
A second defective state in which the printing line is in a state where two dots are missing compared to the reference shape;
A third defective state in which the print line is in a state where 3 dots or more are missing compared to the reference shape;
A fourth defect state in which the print line is shifted in a predetermined first direction compared to the reference position;
A fifth defect state in which the print line is shifted in a second direction orthogonal to the first direction as compared to the reference position;
A sixth defect state in which the print line is shifted in the first direction and the second direction compared to the reference position;
A seventh defect state in which the print line is obliquely displaced compared to the reference position;
Have
In the defect state coefficient table,
The defect state coefficient corresponding to the first defect state is a first defect state coefficient;
The failure state coefficient corresponding to the second failure state is a second failure state coefficient that is larger than the first failure state coefficient;
The defect state coefficient corresponding to each of the third defect state, the fourth defect state, the fifth defect state, and the sixth defect state is a third defect state coefficient that is larger than the second defect state coefficient. Yes,
The cleaning time predicting apparatus according to claim 3, wherein the failure state coefficient corresponding to the seventh failure state is a fourth failure state coefficient larger than the third failure state coefficient. The standby time coefficient determination unit is described in any one of claims 1 to 4, wherein the standby time coefficient is calculated by the following equation, where D2 is the standby time coefficient and t is the standby time. Cleaning time prediction device.

When the failure frequency coefficient determination unit is D3, the failure frequency is n, and the predetermined constant is α,
D3 = exp (αn)
The cleaning time prediction apparatus according to claim 1, wherein the defect frequency coefficient is calculated by an expression represented by:   7. The cleaning time predicting apparatus according to claim 1, wherein the cleaning time predicting unit predicts a cleaning time using a Gaussian process with reference to the predicted feature value and the feature value table. . A cleaning time prediction device according to any one of claims 1 to 7,
The ink jet printer including the ink head, a placement unit on which a recording medium is placed, and a print control device;
With a printing system. The print control device includes a check pattern printing unit that prints the check pattern on the recording medium placed on the placement unit.
A communication device communicably connected to the control device, and a photographing device for photographing the check pattern printed on the recording medium;
The printing system according to claim 8, wherein the control device includes an image storage unit that stores an image of the check pattern captured by the imaging device in the storage unit. The control device includes a cleaning time transmission unit that transmits an estimated cleaning time that is a cleaning time predicted by the cleaning time prediction unit to the print control device,
The inkjet printer is
A cap attached to the ink head so as to cover the nozzles of the ink head;
A cap moving mechanism for moving the cap so as to be detachable from the ink head;
A suction pump connected to the cap and sucking ink in the ink head when the cap is attached to the ink head;
With
The printing control device performs cleaning for cleaning the ink head by controlling the ink in the ink head to be sucked by the suction pump during the predicted cleaning time transmitted by the cleaning time transmitting unit. The printing system according to claim 9, comprising a control unit. The check pattern printing unit is configured to print the check pattern on the recording medium placed on the placement unit after the cleaning of the ink head is completed by the cleaning control unit.
The image storage unit stores the image of the check pattern photographed by the photographing apparatus in the storage unit, the image of a completion check pattern that is the check pattern after cleaning is completed,
The control device includes:
Based on the completion check pattern, a determination unit that determines whether the ejection failure of the nozzle has been eliminated,
When it is determined by the determination unit that the ejection failure of the nozzle has been eliminated, an addition unit that adds the predicted feature amount and the predicted cleaning time in association with the feature amount table;
The printing system according to claim 10, comprising: The control device includes a re-cleaning designation unit that transmits a re-cleaning signal that is a signal for performing cleaning again to the print control device when the determination unit determines that the ejection failure of the nozzle has not been eliminated,
The printing system according to claim 11, wherein the cleaning control unit cleans the ink head after the print control apparatus receives the re-cleaning signal.

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