Printer, ink supply device, and ink supply method

Abstract

To flexibly and appropriately respond to abnormalities in ink supply.SOLUTION: A printer 100 that performs printing using an inkjet method, comprises: an inkjet head 102 that discharges ink supplied from a main tank 106 being an ink container; a sub-tank being a container that stores ink in the middle of a supply path of ink from the main tank 106 to the inkjet head 102; a liquid passing quantity detection unit that detects an ink passing quantity being a quantity of ink flowing per unit time from the main tank 106 to the sub-tank; and a notification unit 116 being notification means that notifies a user of an alarm based on the ink passing quantity detected by the liquid passing quantity detection unit. The liquid passing quantity detection unit detects the ink passing quantity during the printing operation and causes the notification unit 116 to notify a user of an alarm corresponding to the detected ink passing quantity.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a printing apparatus, an ink supplying apparatus, and an ink supplying method. [Background technology]

[0002] Inkjet printers, which are printing devices that perform printing using an inkjet method, have been widely used in the past. In addition, a commonly used configuration of inkjet printers is one in which ink is supplied to an inkjet head from an ink container such as an ink cartridge that is external to the inkjet head (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-225564 A Summary of the Invention [Problem to be solved by the invention]

[0004] When ink is supplied to an inkjet head from an ink container outside the inkjet head, an abnormality in the ink supply may affect the printing operation. In response to this, Patent Document 1 discloses a method of setting a threshold value for the life of a filter as a value of the amount of ink passing through the filter and notifying the user. With this configuration, it is possible to urge the user to replace the filter before a problem occurs due to, for example, clogging of the filter.

[0005] However, the timing at which an abnormality in the ink supply occurs is likely to vary depending on the installation environment of the printing device, variations in ink characteristics due to differences in ink production lots, etc. For this reason, it has been desirable to deal more flexibly with abnormalities in the ink supply caused by clogged filters, etc. The present invention has an object to provide a printing device, an ink supply device, and an ink supply method that can solve the above problems. [Means for solving the problem]

[0006] The inventors of the present application have conducted intensive research into a method for more flexibly responding to an abnormality in the supply of ink from an ink container to an inkjet head. In addition, in this intensive research, more specifically, a method for appropriately avoiding the occurrence of defects related to a subtank when a subtank is provided between the ink container and the inkjet head has been examined. Then, focusing on the ink passage amount, which is the amount of ink flowing from the ink container to the subtank per unit time, the inventors have considered issuing an alarm when the ink passage amount changes. The inventors have also considered issuing an alarm in stages according to the ink passage amount. With this configuration, for example, when an abnormality occurs in the supply of ink from the ink container to the inkjet head, the user can be appropriately notified. Furthermore, in this case, by issuing a staged notification, for example, an alarm can be issued according to the magnitude of the problem. This also makes it possible to, for example, urge the user to take action before a major problem occurs.

[0007] The inventor of the present application has found the features necessary to obtain such an effect, and has arrived at the present invention. In order to solve the above problems, the present invention provides a printing device that performs printing by an inkjet method, comprising an inkjet head that ejects ink supplied from an ink container that stores ink, a subtank that is a container that stores ink in the middle of an ink supply path from the ink container to the inkjet head, a liquid passing amount detection unit that detects an ink passing amount, which is the amount of ink flowing from the ink container to the subtank per unit time, and a notification means that issues an alarm based on the ink passing amount detected by the liquid passing amount detection unit, and the liquid passing amount detection unit causes the notification means to issue a graded alarm according to the detected ink passing amount.

[0008] In this configuration, an alarm is issued in stages according to the ink flow rate, so that, for example, the state of ink supply from the ink container to the subtank can be flexibly and appropriately notified to the user. Therefore, in the case where an abnormality occurs in the ink supply from the ink container to the inkjet head, for example, the user can be appropriately notified. This also makes it possible to flexibly and appropriately respond to, for example, an abnormality in the ink supply.

[0009] In addition, in this case, by performing step-by-step notification, for example, an alarm can be issued according to the severity of the problem that has occurred, and it is possible to urge the user to take action before a major problem occurs. This also makes it possible to more reliably and appropriately prompt the user to take action before the printing device becomes inoperable, for example, to avoid the occurrence of a malfunction or prevent the damage from spreading. More specifically, in this case, for example, damage to devices related to the supply of ink to the subtank and the spread of damage can be appropriately prevented. Therefore, with this configuration, for example, the occurrence of malfunctions related to the subtank can be appropriately prevented.

[0010] In this configuration, the notification means notifies the user of an alarm by using sound or light that appeals to the user's hearing or vision, for example, by a voice notification or a warning display on a display. The notification means may notify an alarm in stages, for example, by at least two stages according to the ink flow rate. More specifically, the notification means may notify, as staged alarms, at least a first alarm indicating an abnormality in the ink flow rate in a state in which the ink supply from the ink container to the subtank can be continued, and a second alarm indicating that the ink flow rate has reached a state in which the ink supply from the ink container to the subtank should be stopped, according to the ink flow rate detected by the ink flow rate detection unit. In addition, the ink flow rate detection unit may cause the notification means to notify the first alarm when it determines that the ink flow rate is less than a first threshold value. Then, the notification means may cause the notification means to notify the second alarm when it determines that the ink flow rate is less than a second threshold value that is less than the first threshold value. With this configuration, for example, the notification means can be made to appropriately issue a stepped alarm according to the ink flow rate. In this case, the ink flow rate detection unit can be made to issue a first alarm when it determines that the ink flow rate is less than a first threshold value and equal to or greater than a second threshold value.

[0011] Also, in this configuration, the printing device performs printing using, for example, a plurality of mutually different color inks. In this case, the printing device includes, for example, an inkjet head and a subtank for each color of ink. Also, in this case, the liquid passing amount detection unit detects, for example, the ink passing amount for each subtank (each color of ink). Then, if an abnormality occurs in the ink passing amount corresponding to any of the subtanks, an alarm is generated in the notification means. In this case, the liquid passing amount detection unit may, for example, cause the notification means to generate an alarm associated with the subtank in which an abnormality occurs in the ink passing amount.

[0012] In this configuration, the printing device may circulate ink between the ink container and the subtank. In this case, the ink passing amount detection unit may detect the ink passing amount based on the amount of ink stored in the subtank. More specifically, in this case, the printing device further includes a supply flow path that is a flow path for flowing ink supplied from the ink container to the subtank, a circulation flow path that is a flow path for flowing ink returned from the subtank to the ink container, a supply pump that is a pump for flowing ink supplied from the ink container to the subtank through the supply flow path, a circulation pump that is a pump for flowing ink returned from the subtank to the ink container through the circulation flow path, and an ink amount detection unit that detects the amount of ink stored in the subtank. The ink passing amount detection unit detects the ink passing amount based on, for example, the operating states of the supply pump and the circulation pump and the amount of ink in the subtank detected by the ink amount detection unit. With this configuration, for example, the ink passing amount can be appropriately detected.

[0013] The sub-tank may have a configuration including, for example, a first ink storage section that is an ink storage section connected to the ink container via a supply flow path, and a second ink storage section that is an ink storage section connected to the ink container via a circulation flow path. In this case, for example, the second ink storage section is separated from the first ink storage section by a partition wall. Then, for example, ink that overflows the partition wall is supplied from the first ink storage section to the second ink storage section.

[0014] The printing device may further include a pump control unit that controls the operation of the supply pump and the circulation pump based on the amount of ink in the subtank detected by the ink amount detection unit. In this case, the ink amount detection unit detects, for example, a first storage amount, which is the amount of ink stored in the first ink storage unit, and a second storage amount, which is the amount of ink stored in the second ink storage unit. If the first storage amount is less than the first reference amount and the second storage amount is less than the second reference amount, the pump control unit causes the supply pump and the circulation pump to perform an ink supply operation in which ink is supplied from the ink container to the subtank via the supply flow path and ink is not returned from the subtank to the ink container via the circulation flow path. With this configuration, for example, when the amount of ink in the subtank becomes low, ink can be appropriately supplied from the ink container to the subtank.

[0015] Furthermore, if the second storage amount does not become equal to or greater than the second reference amount even after a first time has elapsed after the supply pump and the circulation pump have started the ink supply operation, the liquid passing amount detection unit determines, for example, that the ink passing amount is less than the first threshold. Furthermore, if the second storage amount does not become equal to or greater than the second reference amount even after a second time longer than the first time has elapsed after the supply pump and the circulation pump have started the ink supply operation, the liquid passing amount detection unit determines, for example, that the ink passing amount is less than a second threshold that is smaller than the first threshold. With this configuration, for example, it is possible to appropriately detect the ink passing amount.

[0016] In this configuration, the ink passage amount detection unit may detect an abnormality in the ink passage amount based on, for example, an ink passage amount history that records past ink passage amounts. With this configuration, for example, an abnormality in the ink passage amount can be more appropriately detected. In this case, the ink passage amount detection unit may detect an abnormality in the ink passage amount by, for example, comparing an initial value of the ink passage amount with the current ink passage amount, or based on a change in the ink passage amount over time.

[0017] In addition, in this configuration, the printing device may further include a filter that allows ink to pass through the flow path that flows the ink supplied from the ink container to the subtank. In this case, the liquid passing amount detection unit detects, for example, whether or not there is an abnormality in the ink passing amount. If the liquid passing amount detection unit detects that the ink passing amount is abnormal, it is possible to reduce the amount of ink supplied from the ink container to the subtank so as to reduce the flow rate of ink passing through the filter. With this configuration, for example, if an abnormality in the ink passing amount occurs due to clogging of the filter, it is possible to appropriately prevent an amount of ink that cannot pass through the filter from being supplied to the filter.

[0018] In addition, in the case where the printing device includes a supply flow path and a circulation flow path, when the ink flow rate detection unit detects that the ink flow rate is abnormal, it is possible to stop, for example, the operation of returning ink from the subtank to the ink container via the circulation flow path. With this configuration, it is possible to appropriately prevent the ink in the subtank from running out in a short time, for example, when the amount of ink supplied from the ink container to the subtank decreases. In addition, when the ink flow rate detection unit detects that the ink flow rate is abnormal, it is possible to stop, for example, the operation of ejecting ink from the inkjet head. With this configuration, it is possible to appropriately prevent, for example, the inkjet head or the printing device from breaking down due to the printing operation being continued in a state where the ink flow rate is abnormal.

[0019] Furthermore, as a configuration of the present invention, it is also possible to consider configurations of an ink supply device, an ink supply method, etc. having the same characteristics as those described above. In these cases, for example, the same effects as those described above can be obtained. Effect of the Invention

[0020] According to the present invention, for example, it is possible to deal flexibly and appropriately with abnormalities in the supply of ink. [Brief description of the drawings]

[0021] [Figure 1] 1 is a diagram showing an example of a configuration of a main part of a printing device 100 according to an embodiment of the present invention. [Diagram 2] 2A and 2B are diagrams illustrating a more specific configuration of the ink supply system 108. Fig. 2A shows an example of the configuration of the ink supply system 108. Fig. 2B shows an example of the configuration of a sub-tank 202 in the ink supply system 108. [Diagram 3] 3A and 3B are diagrams for explaining in more detail the control etc. performed by the control unit 120. Fig. 3A shows an example of the functional configuration of the control unit 120. Fig. 3B shows an example of the control performed by a pump control unit 404. [Figure 4] 13 is a flowchart showing an example of the operation of a fluid passing amount detection unit 410. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of the configuration of a main part of a printing device 100 according to an embodiment of the present invention. In this example, the printing device 100 is an inkjet printer that performs printing on a medium 50 to be printed by an inkjet method, and includes a plurality of inkjet heads 102, a platen 104, a plurality of main tanks 106, an ink supply system 108, a carriage 110, a scan drive unit 112, a maintenance unit 114, an alarm unit 116, and a control unit 120. Except for the points described below, the printing device 100 may have the same or similar features as a known inkjet printer. For example, the printing device 100 may further include a configuration that is the same or similar to a known inkjet printer, in addition to the configuration shown in FIG. 1. In addition, in this example, the printing device 100 is also an example of an ink supply device that supplies ink from the main tank 106 to the inkjet head 102.

[0023] The multiple inkjet heads 102 are ejection heads that eject ink supplied from multiple main tanks 106 via an ink supply system 108 onto the medium 50. In this example, the multiple inkjet heads 102 eject ink of different colors. Each inkjet head 102 has multiple nozzles and ejects ink from each nozzle according to the image to be printed. The platen 104 is a platform-like member that faces the multiple inkjet heads 102 and holds the medium 50.

[0024] The main tanks 106 are ink containers that store ink to be supplied to the inkjet heads 102. In this example, each of the main tanks 106 stores ink of a different color, and supplies ink to one of the inkjet heads 102 via an ink supply system 108. For example, an ink bottle or an ink cartridge can be suitably used as the main tank 106. In this example, an ink container that can be refilled with ink is used as the main tank 106. In this case, it is considered that the ink supply system 108 is refilled with ink while the main tank 106 is still installed in the printing device 100. In addition, it is also possible to use an ink container that can be removed from the printing device 100 and replaced as the main tank 106. In this case, the main tank 106 can be considered as, for example, a member other than a component of the printing device 100.

[0025] The ink supply system 108 includes an ink supply path for supplying ink from the main tanks 106 to the inkjet heads 102. In this embodiment, the ink supply system 108 includes a sub-tank for storing ink between the main tank 106 and the inkjet heads 102, and a filter for passing ink supplied from the main tank 106 to the sub-tank. A more specific configuration of the ink supply system 108 will be described in more detail later. The carriage 110 is a holding member for holding the inkjet heads 102. In this embodiment, the carriage 110 holds a part of the ink supply system 108 together with the inkjet heads 102. More specifically, in this embodiment, the carriage 110 holds the sub-tank in the ink supply system 108. With this configuration, for example, the sub-tank can be appropriately installed near the inkjet head 102.

[0026] The scan driver 112 is a driver that causes the inkjet heads 102 to perform a scanning operation in which the inkjet heads 102 move relative to the medium 50. In this example, the scan driver 112 causes the inkjet heads 102 to perform a main scanning operation and a sub-scanning operation. In this case, the main scanning operation can be considered to be, for example, an operation of ejecting ink while moving relative to the medium 50 in a predetermined main scanning direction. In the main scanning operation, the scan driver 112 causes the inkjet heads 102 to eject ink to an ink ejection position selected according to an image to be printed. In the sub-scanning operation, for example, an operation of moving relative to the medium 50 in a sub-scanning direction perpendicular to the main scanning direction can be considered. The scan driver 112 changes the range of the medium 50 that faces the inkjet heads 102 by, for example, causing the inkjet heads 102 to perform a sub-scanning operation between main scanning operations. This also causes the scan driver 112 to cause the inkjet heads 102 to eject ink onto each position on the medium 50 .

[0027] The maintenance unit 114 is configured to perform maintenance operations on the multiple inkjet heads 102. In this example, the maintenance unit 114 performs maintenance such as purging, flushing, wiping (wiping with cleaning water) on the multiple inkjet heads 102 at a predetermined timing during, for example, a printing operation (drawing).

[0028] The notification unit 116 is configured to notify the user of the printing device 100 of various information. In this example, the notification unit 116 is an example of a notification means, and notifies the user of an alarm using sound or light that appeals to the user's hearing or vision, for example, by sound notification or warning display on a display. In this case, for example, a speaker or a display in the printing device 100 can be considered to correspond to the notification unit 116. In this example, the notification unit 116 notifies, for example, an alarm regarding an abnormality in the supply of ink supplied from the main tank 106 to a sub-tank in the ink supply system 108. In this case, the notification unit 116 notifies an alarm in multiple stages for each sub-tank corresponding to each of the multiple inkjet heads 102. Examples of alarms notified by the notification unit 116 will be described in more detail later.

[0029] The control unit 120 is, for example, a part including the CPU of the printing device 100, and controls the operation of each part of the printing device 100 according to a program (for example, firmware, etc.) that controls the operation of the printing device 100. In this case, for example, it is conceivable that the operation of the control unit 120 is realized by the CPU or the like taking on various functional configurations according to the program. Furthermore, the control unit 120 may be, for example, a configuration corresponding to a control unit in the printing device 100. The functional configuration of the control unit 120 will be described in more detail later.

[0030] Next, a more specific configuration of the ink supply system 108 in the printing apparatus 100 will be described in more detail. FIG. 2 is a diagram for explaining a more specific configuration of the ink supply system 108. FIG. 2(a) is a diagram showing an example of the configuration of the ink supply system 108, and shows an example of a configuration for supplying ink from the main tank 106 to one of the inkjet heads 102 in the printing apparatus 100. In this example, the ink supply system 108 has a sub-tank 202, a supply flow path 204, a circulation flow path 206, a plurality of pumps 212 and 214, a degassing module 216, and a filter 218 corresponding to one inkjet head 102. In this case, the ink supply system 108 has these configurations corresponding to each inkjet head 102. In this case, it can be considered that the printing apparatus 100 has each configuration such as the sub-tank 202, the supply flow path 204, and the circulation flow path 206 for each color of ink.

[0031] The sub tank 202 is an ink container that stores ink in the middle of the ink supply path from the main tank 106 to the inkjet head 102. In this example, the sub tank 202 is held on the carriage 110 (see FIG. 1) together with the inkjet head 102, and stores ink in a smaller volume than the main tank 106 near the inkjet head 102. The internal pressure of the sub tank 202 is adjusted to a negative pressure relative to atmospheric pressure, for example, by an adjustment mechanism not shown in FIG. 2(a). By adjusting the internal pressure of the sub tank 202 in this way and supplying ink to the inkjet head 102, it is possible to appropriately prevent ink from leaking from the nozzles of the inkjet head 102, for example.

[0032] In a modified example of the ink supply system 108, the space inside the subtank 202 may be open to the atmosphere, for example. In this case, it can be considered that the pressure inside the subtank 202 is balanced with the atmospheric pressure. In this case, it is also possible to further provide a pressure adjustment unit (for example, a pressure damper) between the subtank 202 and the inkjet head 102 for adjusting the supply pressure of ink to the inkjet head 102. This pressure adjustment unit adjusts the pressure of ink supplied to the inkjet head 102 to a pressure that is negative with respect to the atmospheric pressure by, for example, lowering the pressure of ink supplied from the subtank 202, which is a supply pressure corresponding to the atmospheric pressure, by a predetermined adjustment amount. Even in this configuration, it is possible to appropriately supply ink to the inkjet head 102, for example.

[0033] The supply flow path 204 is a flow path through which ink is supplied from the main tank 106 to the sub tank 202 flows. For example, a tube through which ink passes can be suitably used as the supply flow path 204. In this example, the supply flow path 204 flows ink from the main tank 106 to the sub tank 202 via a degassing module 216 and a filter 218, as shown in the figure. The circulation flow path 206 is an ink flow path for circulating ink between the main tank 106 and the sub tank 202, and flows ink through a path different from the supply flow path 204 so as to return ink from the sub tank 202 to the main tank 106. For example, a tube through which ink passes can be suitably used as the circulation flow path 206. The pump 212 is an example of a supply pump, and flows ink supplied from the main tank 106 to the sub tank 202 through the supply flow path 204. The pump 214 is an example of a circulation pump, and causes the ink being returned from the sub tank 202 to the main tank 106 to flow through the circulation flow path 206. As the pumps 212 and 214, for example, a known tube pump or the like can be suitably used.

[0034] The degassing module 216 is a component for removing air from the ink, and is installed in the middle of the supply flow path 204 to degas the ink supplied from the main tank 106 to the sub tank 202. The filter 218 is a component for removing foreign matter and solidified ink from the ink, and is installed in the middle of the supply flow path 204 to remove foreign matter from the ink supplied from the main tank 106 to the sub tank 202. In this configuration, by supplying ink from the main tank 106 to the sub tank 202 via the degassing module 216 and the filter 218, it is possible to appropriately supply ink in a state suitable for ink ejection from the inkjet head 102 to the sub tank 202. In this case, by returning ink from the sub tank 202 to the main tank 106 via the circulation flow path 206 and circulating the ink, it is possible to appropriately prevent the ink in the sub tank 202 from, for example, passing an excessive time after passing through the degassing module 216 and the filter 218. Therefore, according to this embodiment, for example, ink in a state suitable for ink ejection can be more appropriately supplied to the inkjet head 102.

[0035] In this example, the control unit 120 (see FIG. 1) of the printing device 100 controls the supply of ink from the main tank 106 to the sub tank 202 and the circulation of ink based on the amount of ink stored in the sub tank 202. The sub tank 202 has a configuration that is preferable for performing such control. More specifically, in this example, the sub tank 202 has a partition wall 300, an IN-side storage section 302, an OUT-side storage section 304, and multiple liquid level detection sensors 306, 308, as shown in FIG. 2(b), for example. FIG. 2(b) shows an example of the configuration of the sub tank 202 in the ink supply system 108.

[0036] The partition wall 300 is a wall that separates the IN-side storage section 302 and the OUT-side storage section 304. In this example, the partition wall 300 separates the IN-side storage section 302 and the OUT-side storage section 304 so that when the liquid level of the ink stored in the IN-side storage section 302 exceeds a predetermined height, the overflowing ink flows from the IN-side storage section 302 to the OUT-side storage section 304. The IN-side storage section 302 is an example of a first ink storage section, and is connected to the main tank 106 via the supply flow path 204 to store ink supplied from the main tank 106 to the sub tank 202. The OUT-side storage section 304 is an example of a second ink storage section, and is connected to the main tank 106 via the circulation flow path 206 to store ink to be sent to the main tank 106 when the ink is circulated.

[0037] Liquid level detection sensor 306 is a sensor that detects the position of the ink level in IN-side storage section 302, and detects the position of the ink level based on the position (height) of float 312 floating on the ink in IN-side storage section 302. In this example, liquid level detection sensor 306 detects the position of the ink level in IN-side storage section 302 near a position corresponding to the height of partition wall 300 as shown in the figure. In this case, the height of partition wall 300 can be considered to be, for example, the height at which ink overflows beyond partition wall 300. In this way, liquid level detection sensor 306 detects the position of the ink level that indicates whether or not an amount of ink is stored in IN-side storage section 302 that is sufficient to supply ink from IN-side storage section 302 to OUT-side storage section 304. The liquid level detection sensor 308 is a sensor that detects the position of the ink level in the OUT side storage section 304, and detects the position of the ink level based on the position (height) of a float 314 floating on the ink in the OUT side storage section 304. In this example, the liquid level detection sensor 308 detects the position of the ink level in the OUT side storage section 304 at a position lower than the height of the partition wall 300 as shown in the figure. In this case, the liquid level detection sensor 308 detects the position of the ink level that indicates whether or not an amount of ink is stored in the OUT side storage section 304 that is sufficient to perform a circulation operation to return the ink to the main tank 106. As the liquid level detection sensors 306 and 308, it is preferable to use a sensor that can detect the position of the ink level in multiple stages. As such a sensor, for example, a well-known three-point liquid level sensor or the like can be suitably used.

[0038] With the above configuration, in the subtank 202 of this example, ink supplied from the main tank 106 is first supplied into the IN-side storage section 302. When a sufficient amount of ink is stored in the IN-side storage section 302 and the position of the liquid level exceeds the height of the partition wall 300, ink overflowing the partition wall 300 is supplied from the IN-side storage section 302 to the OUT-side storage section 304. When a predetermined amount or more of ink is stored in the OUT-side storage section 304, the ink in the OUT-side storage section 304 is returned to the main tank 106 via the circulation flow path 206. According to this example, for example, ink can be appropriately supplied from the main tank 106 to the subtank 202, and ink can be appropriately circulated between the main tank 106 and the subtank 202.

[0039] Here, in this example, ink is also circulated between the inkjet head 102 and the subtank 202. In this case, the ink is supplied from the subtank 202 to the inkjet head 102 from the IN-side storage section 302 side, as shown in the figure, for example. The OUT-side storage section 304 side receives the ink returning from the inkjet head 102. Therefore, in this example, the ink is supplied from the IN-side storage section 302 to the OUT-side storage section 304 through a path that overflows the partition wall 300, as well as through a path that passes through the inkjet head 102. In this example, the amount of ink in the subtank 202 is detected by a plurality of liquid level detection sensors 306, 308 in the subtank 202, and the control section 120 controls the operation of a plurality of pumps 212, 214, etc. based on the result, thereby controlling the ink supply and circulation operations. Hereinafter, the functional configuration of the control section 120 and the control of the ink supply and circulation performed by the control section 120 will be described in more detail.

[0040] Fig. 3 is a diagram for explaining in more detail the control etc. performed by the control unit 120. Fig. 3(a) is a diagram showing an example of the functional configuration of the control unit 120, and shows an example of the configuration of the control unit 120 using functional blocks showing the control etc. performed by the control unit 120. Fig. 3(b) shows an example of the control performed by the pump control unit 404.

[0041] In this example, the control unit 120 functionally includes a scan control unit 402, a pump control unit 404, a maintenance control unit 406, an ink amount detection unit 408, a liquid passing amount detection unit 410, and a storage unit 412. In this case, for example, it can be considered that at least a part of the control unit 120 functions as various functional configurations. More specifically, in this case, for example, a CPU included in the control unit 120 operates according to a program such as firmware, thereby functioning as the scan control unit 402, the pump control unit 404, the maintenance control unit 406, the ink amount detection unit 408, and the liquid passing amount detection unit 410. In addition, for example, the CPU included in the control unit 120 functions as the storage unit 412 together with a storage unit such as a memory or storage. In addition to the above configuration, the control unit 120 may further include other functional configurations according to the operations performed by the printing device 100.

[0042] Among these components, the scan control unit 402 controls the main scanning operation and sub-scanning operation executed in the printing device 100. The pump control unit 404 controls the operation of pumps such as pumps 212, 214 (see FIG. 2) in the ink supply system 108. In this example, the pump control unit 404 controls the operation of pumps 212, 214 based on the amount of ink in the subtank 202 (see FIG. 2) detected by an ink amount detection unit 408. The maintenance control unit 406 controls the maintenance operation executed in the maintenance unit 114 (see FIG. 1).

[0043] Further, the ink amount detection unit 408 detects the amount of ink stored in the subtank 202. More specifically, in this example, the ink amount detection unit 408 detects a first storage amount, which is the amount of ink stored in the IN side storage unit 302 (see FIG. 2), based on the output of the liquid level detection sensor 306 (see FIG. 2) in the subtank 202. Further, the ink amount detection unit 408 detects a second storage amount, which is the amount of ink stored in the OUT side storage unit 304 (see FIG. 2), based on the output of the liquid level detection sensor 308 (see FIG. 2) in the subtank 202. In this case, the liquid level detection sensors 306, 308 can be considered to be, for example, a configuration that is outside the control unit 120. Furthermore, when the configuration of the printing device 100 or the part considered to be the control unit 120 is changed, the sensors such as the liquid level detection sensors 306, 308 can also be considered to be components that the control unit 120 has.

[0044] The liquid passing amount detection unit 410 detects the ink passing amount, which is the amount of ink flowing from the main tank 106 (see FIG. 1) to the sub tank 202 per unit time. In this example, the liquid passing amount detection unit 410 detects the ink passing amount based on the operating state of the pumps 212 and 214 controlled by the pump control unit 404 and the first and second stored amounts detected by the ink amount detection unit 408. The liquid passing amount detection unit 410 further judges whether or not there is an abnormality in the ink passing amount, and when an abnormality occurs, causes the notification unit 116 (see FIG. 1) to notify an alarm. The liquid passing amount detection unit 410 can be considered as an example of a judgment means for judging whether or not there is an abnormality in the ink passing amount. The method of detecting the ink passing amount in the liquid passing amount detection unit 410 and the operation of causing the notification unit 116 to notify an alarm will be described in more detail later. The memory unit 412 stores and manages parameters used for control performed by the control unit 120. In this embodiment, the storage unit 412 also stores a history of the ink passage amount that records the past ink passage amount. The use of the history of the ink passage amount will be described in more detail later.

[0045] Next, the control of the pump operation performed by the pump control unit 404 will be described as an example of the control executed by the control unit 120. In addition, hereinafter, the operation of the functional components of the control unit 120, such as the pump control unit 404, will be described simply as the operation of those components. As described above, in this example, the pump control unit 404 controls the operation of the pumps 212, 214 in the ink supply system 108 based on the first storage amount and the second storage amount, which are the amounts of ink in the subtank 202 detected by the ink amount detection unit 408.

[0046] More specifically, in this example, ink amount detection unit 408 detects which of five levels, Low, Middle, High, Near Full, and Limit, the first storage amount corresponds to in association with the position of the liquid level (IN side liquid level) in IN side storage unit 302. Similarly, ink amount detection unit 408 detects which of five levels, Low, Middle, High, Near Full, and Limit, the second storage amount corresponds to in association with the position of the liquid level (OUT side liquid level) in OUT side storage unit 304. In this case, Low indicates a state in which the storage amount is the smallest, followed by Middle, High, Near Full, and Limit in order. The storage amount determined to correspond to each level is set individually for each of liquid level detection sensor 306 and liquid level detection sensor 308 according to the mounting height of each of liquid level detection sensor 306 and liquid level detection sensor 308. For example, ink amount detection unit 408 detects the first storage amount based on a plurality of reference amounts set according to a plurality of different liquid level positions at a position close to the height of partition wall 300 (see FIG. 2) that separates IN-side storage unit 302 and OUT-side storage unit 304. In addition, ink amount detection unit 408 detects the second storage amount based on a plurality of reference amounts set according to a plurality of different liquid level positions at a predetermined position lower than the height of partition wall 300.

[0047] In this example, the pump control unit 404 causes the pumps 212, 214 to perform one of the operations selected from an ink supply operation, an ink supply circulation operation, and an ink circulation operation, depending on the first storage amount and the second storage amount. In this case, the ink supply operation is an operation in which ink is supplied from the main tank 106 to the sub tank 202 via the supply flow path 204 (see FIG. 2), and ink is not returned from the sub tank 202 to the main tank 106 via the circulation flow path 206 (see FIG. 2). The ink supply circulation operation is an operation in which ink is supplied from the main tank 106 to the sub tank 202 via the supply flow path 204, and ink is returned from the sub tank 202 to the main tank 106 via the circulation flow path 206. The ink circulation operation refers to an operation in which ink is not supplied from the main tank 106 to the sub tank 202 via the supply flow path 204, and ink is returned from the sub tank 202 to the main tank 106 via the circulation flow path 206.

[0048] Moreover, the pump control unit 404 adjusts the amount of ink stored in each of the IN-side storage unit 302 and the OUT-side storage unit 304 to one of states A, B, and C shown in FIG. 3B by causing the pumps 212 and 214 to perform these operations. In this case, states A, B, and C are states determined according to the magnitude relationship between the reference amounts Li1 and Li2 shown in the figure and the first storage amount, and the magnitude relationship between the reference amounts Lo1 and Lo2 and the second storage amount. In this example, the reference amount Li2 is an example of the first reference amount. The reference amount Lo1 is an example of the second reference amount. Regarding state A, for example, it can be considered as a state in which the first storage amount is less than the reference amount Li2 and the second storage amount is less than the reference amount Lo1. In the case shown in the figure, the second storage amount in state A is less than the reference amount Lo1 and is equal to or greater than the reference amount Lo2. State B can be considered, for example, as a state in which the first storage amount is less than the reference amount Li2 and the second storage amount is equal to or greater than the reference amount Lo1. State C can be considered, for example, as a state in which the first storage amount is equal to or greater than the reference amount Li2 and the second storage amount is equal to or greater than the reference amount Lo1. In the case shown in the figure, the first storage amount in state C is equal to or greater than the reference amount Li2 and less than the reference amount Li1.

[0049] When the amount of ink stored in the subtank 202 is in state A, the pump control unit 404 causes the pumps 212 and 214 to perform an ink supply operation. When the amount of ink stored is in state B, the pump control unit 404 causes the pumps 212 and 214 to perform an ink supply circulation operation. When the amount of ink stored is in state C, the pump control unit 404 causes the pumps 212 and 214 to perform an ink circulation operation. By controlling these operations, the pump control unit 404 transitions the state of the amount of ink stored in the subtank 202 between states A, B, and C. With this configuration, for example, when the amount of ink in the subtank 202 becomes low, ink can be appropriately supplied from the main tank 106 to the subtank 202. When a sufficient amount of ink is stored in the subtank 202, ink can be appropriately circulated between the main tank 106 and the subtank 202 by returning ink from the subtank 202 to the main tank 106.

[0050] In this example, in order to ensure an appropriate ink supply capacity, the capacity of the ink supply pump 212 is set to be greater than the capacity of the circulation pump 214. Therefore, during normal operation, of the states A, B, and C, transitions occur mainly between states B and C. In this case, for example, at a timing when the amount of ink consumed increases, the ink in the subtank 202 decreases, causing a transition to state A, so that ink can be more appropriately supplied to the subtank 202. This also maintains the transition between states A, B, and C for the amount of ink stored in the subtank 202, as described above.

[0051] In addition, for example, when the ink consumption amount temporarily changes significantly or when an abnormality occurs in the supply or circulation of ink, the amount of ink stored in the subtank 202 may be in a state other than states A, B, and C. Therefore, in this example, as shown in parentheses in the figure, the ink supply operation, the ink supply and circulation operation, or the ink circulation operation is associated with states other than states A, B, and C. In this case, for example, operations other than these may be associated with some states. In addition, such association between states and operations may be stored in the storage unit 412 in the form of a control table. In this case, the operation of the pump control unit 404 can be considered to control the operations of the pumps 212 and 214 according to the control table stored in the storage unit 412. According to this example, for example, the supply of ink to the subtank 202 and the circulation of ink can be appropriately performed.

[0052] Next, a method for detecting the ink passing amount in the ink passing amount detection unit 410 and an operation for causing the notification unit 116 (see FIG. 1) to issue an alarm will be described in more detail. As described above, in this example, the ink passing amount detection unit 410 judges whether or not there is an abnormality in the ink passing amount from the main tank 106 to the sub tank 202, and causes the notification unit 116 to issue an alarm if an abnormality occurs. In this case, the ink passing amount detection unit 410 detects the ink passing amount based on the operating state of the pumps 212 and 214 controlled by the pump control unit 404 and the first and second storage amounts detected by the ink amount detection unit 408, for example, according to the operation shown in the flowchart in FIG. 4. Then, the notification unit 116 issues a step-by-step alarm in at least two stages according to the ink passing amount.

[0053] FIG. 4 is a flow chart showing an example of the operation of the liquid passing amount detection unit 410, and shows an example of the operation of the liquid passing amount detection unit 410 after the ink storage amount in the subtank 202 becomes state A. In this example, when the ink passing amount from the main tank 106 to the subtank 202 decreases, the liquid passing amount detection unit 410 first causes the notification unit 116 to notify a warning level alarm. Then, when the ink passing amount further decreases, the notification unit 116 causes the notification unit 116 to notify an error level alarm. In this case, the warning level alarm is an example of a first alarm indicating an abnormality in the ink passing amount in a state in which the ink supply from the main tank 106 to the subtank 202 can be continued. The warning level alarm can be considered, for example, as an alarm that calls the user's attention while the printing operation is continuing. The error level alarm is an example of a second alarm indicating that the ink passing amount has reached a state in which the ink supply from the main tank 106 to the subtank 202 should be stopped. An error level alarm may be, for example, an alarm indicating that the printing device 100 (see FIG. 1) is inoperable, or an alarm that issues a notice when the supply of ink to the subtank 202 is to be stopped (interrupted).

[0054] As described above, during normal operation in this example, the state of the ink storage amount in the subtank 202 mainly transitions between states B and C described above. However, if the ink flow rate from the main tank 106 to the subtank 202 decreases due to clogging of the filter 218 (see FIG. 2) in the supply flow path 204 (see FIG. 2), for example, the state of the ink storage amount in the subtank 202 changes to state A. In this case, if the decrease in the ink flow rate is minor, the state of the ink storage amount in the subtank 202 returns to state B in a short time. On the other hand, if the ink flow rate decreases more significantly, it may take a long time to return to state B, or it may not be possible to return to state B. Therefore, in this example, when the ink storage amount in the subtank 202 becomes state A, the ink flow rate detection unit 410 detects the ink flow rate based on the elapsed time thereafter.

[0055] More specifically, in the operation of the flowchart shown in Fig. 4, the liquid passing amount detection unit 410 checks whether or not a change to state B has occurred, for example, when a predetermined time has elapsed since state A was reached (S102). In this example, the change from state A to state B can be considered to correspond to the second storage amount in the subtank 202 becoming equal to or greater than the reference amount Lo1, as can be understood from the items shown in Fig. 3(b), for example. Then, in step S102, if it is determined that a change from state A to state B has occurred (S102: Yes), the liquid passing amount detection unit 410 ends the operation of detecting the ink passing amount.

[0056] Furthermore, if it is determined in step S102 that the state has not changed to state B (S102: No), the time that has elapsed since the state became A is compared with preset times T1 and T2 (S104, S106). In this case, time T1 is an example of a first time. Time T2 is an example of a second time that is longer than the first time. Furthermore, the time that has elapsed since the state became A can be considered to be, for example, the time after the pumps 212, 214 start the ink supply operation in response to the control of the pump control unit 404. In this comparison, if the elapsed time has not reached the first time T1 (S104, No), the process returns to step S102 and the subsequent operations are repeated.

[0057] In addition, in this comparison, if the elapsed time exceeds the time T1 (S104: Yes) and does not reach the time T2 (S106: No), the liquid passage amount detection unit 410 determines that the ink passage amount is less than the first threshold value F1 (S108). Based on this determination, the liquid passage amount detection unit 410 executes a liquid passage amount warning process, which is a process performed when the ink passage amount decreases to a warning level (S110). More specifically, in this example, the liquid passage amount detection unit 410 causes the notification unit 116 to notify a warning level alarm as the liquid passage amount warning process. In this example, the printing device 100 continues the printing operation even after the warning level alarm is notified. Therefore, after performing the liquid passage amount warning process, the liquid passage amount detection unit 410 returns to step S102 and repeats the subsequent operations.

[0058] Furthermore, in the comparison between steps S104 and S106, if the elapsed time exceeds the time T2 (S106: Yes), the liquid passing amount detection unit 410 determines that the ink passing amount is less than the second threshold value F2 (S112). In this case, the second threshold value F2 is a threshold value set to a value smaller than the first threshold value F1. Based on this determination, the liquid passing amount detection unit 410 executes a liquid passing amount error process, which is a process performed when the ink passing amount has decreased to an error level (S114). More specifically, in this example, the liquid passing amount detection unit 410 causes the notification unit 116 to notify an alarm of an error level as the liquid passing amount error process, and further stops the printing operation of the printing device 100. In addition, as a result, the liquid passing amount detection unit 410 stops the supply of ink from the main tank 106 to the sub tank 202. Then, the liquid passing amount detection unit 410 ends the operation of the illustrated flowchart.

[0059] In this configuration, for example, the ink passing amount can be appropriately detected based on the elapsed time after the ink storage amount in the subtank 202 becomes the state A. In addition, by detecting the magnitude relationship between the two types of thresholds F1 and F2 and the ink passing amount, for example, the notification unit 116 can be made to appropriately issue a step-by-step alarm. This also makes it possible to issue an alarm according to the magnitude of the problem that has occurred, and to urge the user to take action before a major problem occurs. Therefore, according to this example, for example, when an abnormality occurs in the supply of ink from the main tank 106 to the inkjet head 102 (see FIG. 1) via the subtank 202, a notification can be appropriately issued to the user. This also makes it possible to more flexibly and appropriately respond to, for example, an abnormality in the supply of ink. More specifically, for example, it becomes possible to more reliably and appropriately urge the user to take action before the printing device becomes inoperable, thereby avoiding the occurrence of a malfunction and preventing damage from spreading.

[0060] Also, as described above, in this example, the liquid passing amount detection unit 410 stops the supply of ink from the main tank 106 to the subtank 202 during the liquid passing amount error processing. With this configuration, for example, it is possible to prevent the occurrence of unexpected damage and the spread of damage, and more appropriately improve the safety of the operation of the printing device 100. More specifically, in this case, for example, it is possible to appropriately prevent the occurrence of damage and the spread of damage to devices related to the ink supply to the subtank 202. This also makes it possible to appropriately prevent the occurrence of malfunctions related to the subtank 202, for example.

[0061] Next, supplementary explanations regarding the configurations described above and explanations of modified examples will be given. As described above, in this example, the printing device 100 has each component, such as the subtank 202 used to supply ink from the main tank 106 to the inkjet head 102, for each color of ink. Therefore, in this example, the liquid passing amount detection unit 410 detects the ink passing amount for each subtank 202 corresponding to each color of ink. In addition, when an abnormality occurs in the ink passing amount corresponding to any of the subtanks 202, the liquid passing amount detection unit 410 causes the notification unit 116 to generate an alarm, for example, by associating the detected ink passing amount with the subtank 202 in which the abnormality occurs in the ink passing amount. In this case, the notification unit 116 may generate an alarm while indicating the subtank 202 in which the abnormality occurs.

[0062] In this example, the cause of the decrease in the ink passing amount may be, for example, clogging of the filter 218 in the supply flow path 204. Therefore, the detection of an abnormality in the ink passing amount in the supply flow path 204 may be, for example, detection of an abnormality in the flow rate of ink passing through the filter 218 per unit time. In this case, by having the notification unit 116 issue a step-by-step alarm, it is possible to urge the user to take measures such as replacing the filter 218 before the filter 218 becomes completely clogged and becomes inoperable. In this regard, if the filter 218 becomes inoperable due to being completely clogged, not only will it be impossible to perform printing operations, but it may also be impossible to perform maintenance operations (cleaning) such as purging and flushing by the maintenance unit 114 (see FIG. 1). As a result, it is also possible that the inkjet head 102 may be damaged. In contrast, according to this example, by detecting an abnormality in the amount of ink passing through the inkjet head 102 before the printing device 100 becomes inoperable due to clogging of the filter 218, etc., it is possible to appropriately prevent damage to the inkjet head 102, etc.

[0063] In addition to clogging of the filter 218, other possible causes of a decrease in the ink flow rate include, for example, ink leakage due to damage to the tubes constituting the supply flow path 204, or a malfunction of the pump 212 that prevents ink from being supplied to the subtank 202. Also, for example, a malfunction of the liquid level detection sensors 306, 308 may result in a false detection state in which correct detection is not possible even though ink is actually being supplied to the subtank 202. In contrast, according to this example, even if deviation from the control range occurs due to various causes such as those described above, an alarm can be appropriately issued to prompt the user to take action.

[0064] As described above, the main tank 106 may be, for example, an ink container that can be refilled with ink. The pressure inside the sub tank 202 is adjusted so that ink can be supplied to the inkjet head 102 at an appropriate ink pressure, as described above. However, when the amount of ink in the sub tank 202 decreases due to, for example, consumption of ink in the inkjet head 102, the space inside the sub tank 202 increases relatively, and the negative pressure value increases. In this case, for example, in order to adjust the pressure to an appropriate level, the space inside the sub tank 202 may be opened to the atmosphere. In this case, for example, the ink may be altered due to contact with air, and the filter 218 may be easily clogged. Furthermore, in a configuration in which ink is circulated between the main tank 106 and the sub tank 202 as in this example, the filter 218 may be easily clogged as the ink repeatedly passes through the filter 218. In contrast, according to this example, it is possible to urge the user to take measures such as replacing the filter 218 before the filter 218 becomes completely clogged and becomes inoperable, as described above. Therefore, according to this example, even when a configuration is used in which the filter 218 is easily clogged, it is possible to more appropriately prevent serious problems such as damage to the inkjet head 102 from occurring.

[0065] In addition, the operation performed when an abnormality in the ink flow rate is detected is not limited to the operation described above, and can be modified in various ways. For example, in the case of the operation shown in the flowchart of FIG. 4, when the ink flow rate detection unit 410 determines that the ink flow rate is less than the first threshold value F1 and is equal to or greater than the second threshold value F2, the ink flow rate detection unit 410 causes the notification unit 116 to issue an alarm of warning level. Therefore, when the ink flow rate decreases, the ink flow rate detection unit 410 causes the notification unit 116 to issue only one of the warning level and the error level depending on the ink flow rate. In contrast, in a modified example of the operation performed when an abnormality in the ink flow rate occurs, the ink flow rate detection unit 410 may cause the notification unit 116 to issue both the warning level and the error level alarms when, for example, the ink flow rate becomes less than the second threshold value F2.

[0066] In addition, when the ink passing amount warning process or the ink passing amount error process is executed, various operations other than those described above may be performed. For example, the ink passing amount detection unit 410 may detect the presence or absence of an abnormality in the ink passing amount in the same or similar manner as described above, and when the ink passing amount detection unit 410 detects that the ink passing amount is abnormal, the amount of ink (ink supply amount) supplied from the main tank 106 to the sub tank 202 may be reduced so that the flow rate of ink passing through the filter 218 is reduced. In this case, the reduction in the amount of ink supplied from the main tank 106 to the sub tank 202 may be reduced by, for example, reducing the set amount of ink to be flowed through the supply flow path 204 by the pump 212. With this configuration, when an abnormality in the ink passing amount occurs due to clogging of the filter 218, for example, it is possible to appropriately prevent an amount of ink that cannot pass through the filter 218 from being supplied to the filter 218. In addition, it is possible to adjust the ink supply amount while continuing the printing operation when the ink passing amount warning process is executed. With this configuration, for example, even if an abnormality occurs in the amount of ink passing through, the printing operation can be continued more appropriately.

[0067] As can be understood from the transition operation between states A, B, and C described with reference to FIG. 3B, in this example, the pump control unit 404 stops the circulation operation of returning ink from the sub tank 202 to the main tank 106 when the amount of ink stored in the OUT side storage unit 304 becomes less than a predetermined amount based on the output of the liquid level detection sensor 308. Therefore, when the ink flow rate decreases and the ink supply amount to the sub tank 202 becomes insufficient as a result, the pump control unit 404 controls the operation of the pumps 212 and 214 so as to perform the ink circulation operation intermittently. On the other hand, in a modified example of the operation when an abnormality occurs in the ink flow rate, when the ink flow rate detection unit 410 detects that the ink flow rate is abnormal, the ink circulation operation may be stopped directly in response to the detection. Such control may be, for example, a control that prohibits the operation of returning ink from the sub tank 202 to the main tank 106 through the circulation flow channel 206 when an abnormality occurs in the ink flow rate. With this configuration, for example, when the amount of ink supplied from the main tank 106 to the sub tank 202 decreases, it is possible to appropriately prevent the ink in the sub tank 202 from running out in a short time. It is also possible to control the circulation of ink in this way while continuing the printing operation, for example, when the ink flow warning process is executed. With this configuration, it is possible to more appropriately continue the printing operation, for example, even when an abnormality occurs in the ink flow rate.

[0068] As described above, in this example, when the ink flow rate error process is executed, the printing operation of the printing device 100 is stopped. This also stops the operation of discharging ink from the inkjet head 102. In contrast, in a modified example of the operation when an abnormality in the ink flow rate occurs, for example, the operation of discharging ink from the inkjet head 102 is stopped even when the ink flow rate warning process is executed. In this case, the ink flow rate detection unit 410, for example, stops the operation of discharging ink from the inkjet head 102 corresponding to the subtank 202 in response to detecting an abnormality in the ink flow rate to any of the subtanks 202. With this configuration, for example, it is possible to appropriately prevent the ink in the subtank 202 or the inkjet head 102 from running out by continuing the printing operation in a state where an abnormality in the ink flow rate occurs. This also makes it possible to appropriately prevent the inkjet head 102 or the printing device 100 from breaking down, for example, even when an abnormality in the ink flow rate occurs.

[0069] As described above, in this example, the ink passing amount is compared with the first and second threshold values ​​F1 and F2 by comparing the time elapsed since the state A was reached with the preset times T1 and T2. More specifically, in the above, the ink passing amount is detected mainly based on the output of the liquid level detection sensors 306 and 308 in the subtank 202 and the operating state of the pumps 212 and 214. With this configuration, for example, the ink passing amount can be appropriately detected at low cost. However, the method of detecting the ink passing amount is not limited to the above, and can be changed in various ways. For example, it is possible to install a liquid level sensor in the supply flow path 204 and detect the ink passing amount based on the output of the liquid level sensor. With this configuration, for example, the ink passing amount can be appropriately detected with high accuracy.

[0070] Also, the ink passing amount may change gradually over time. More specifically, for example, when the ink passing amount decreases due to clogging of the filter 218, the ink passing amount may decrease gradually over the operation time of the printing device 100. In this embodiment, as described above, the ink passing amount history is stored in the storage unit 412. In this case, the ink passing amount detection unit 410 may detect the occurrence of an abnormality in the ink passing amount based on the ink passing amount history. In addition to detecting the ink passing amount by the method described above, the ink passing amount history may be further utilized. With this configuration, for example, an abnormality in the ink passing amount may be more appropriately detected. In this case, the ink passing amount detection unit 410 may detect the abnormality in the ink passing amount by comparing the initial value of the ink passing amount with the current ink passing amount, or based on the change in the ink passing amount over time.

[0071] In this case, it is also possible to set a threshold value used to determine an abnormality in the ink flow rate based on the past ink flow rate when the ink flow rate was normal. More specifically, it is also possible to set a threshold value for the ink flow rate based on the ink flow rate at the time of shipment of the printing device 100, at the time of maintenance, or at the start of a printing operation in the printing device 100. In addition, when detecting an abnormality in the ink flow rate by an operation that is the same as or similar to the flowchart shown in Fig. 4, it is also possible to set the times T1 and T2 to be compared with the elapsed time since state A was reached based on the history of the ink flow rate.

[0072] In the above, the configuration of the printing device 100 has been described mainly in the case where ink is ejected onto a medium. In this case, the printing device 100 can be considered as an inkjet printer that draws a two-dimensional image on a medium. In contrast, in a modified example of the configuration of the printing device 100, for example, a 3D printer (3D printing device) that forms a three-dimensional object can be used as the printing device 100. In this case, the modeling table that supports the object being modeled and the object being modeled can be considered as targets onto which ink is ejected. In this case, too, by issuing an alarm or the like in the same manner as above, it is possible to more flexibly and appropriately respond to abnormalities in the supply of ink. [Industrial Applicability]

[0073] The present invention can be suitably used in, for example, a printing device. [Explanation of symbols]

[0074] 50 medium, 100 printing device, 102 inkjet head, 104 platen, 106 main tank, 108 ink supply system, 110 carriage, 112 scan drive unit, 114 maintenance unit, 116 notification unit, 120 control unit, 202 sub tank, 204 supply flow path, 206 circulation flow path, 212 pump, 214 pump, 2 16... degassing module, 218... filter, 300... partition wall, 302... IN side storage section, 304... OUT side storage section, 306... liquid level detection sensor, 308... liquid level detection sensor, 312... float, 314... float, 402... scanning control section, 404... pump control section, 406... maintenance control section, 408... ink amount detection section, 410... liquid passing amount detection section, 412... memory section

Claims

1. A printing device that performs printing using an inkjet method, an inkjet head that ejects ink supplied from an ink container that stores ink; a sub-tank that is a container for storing ink, the sub-tank being located in an ink supply path from the ink container to the inkjet head; a flow rate detection unit that detects an ink flow rate, which is an amount of ink flowing from the ink container to the subtank per unit time; a notification means for notifying an alarm based on the ink passing amount detected by the ink passing amount detection unit; Equipped with the ink passage amount detection unit detects the ink passage amount during a printing operation, and causes the notification unit to issue an alarm corresponding to the detected ink passage amount; The notification unit notifies at least one of the following in response to the ink flow amount detected by the ink flow amount detection unit: a first alarm indicating an abnormality in the ink flow rate while the ink supply from the ink container to the subtank can be continued; a second alarm indicating that the ink flow rate has reached a state in which the supply of ink from the ink container to the subtank should be stopped; and Inform the The liquid passing amount detection unit is when it is determined that the ink flow amount is less than a first threshold value, causing the notification means to issue the first alarm; a second threshold value that is smaller than the first threshold value, the second threshold value being smaller than the second threshold value;

2. When the liquid passing amount detection unit causes the notification means to notify the first alarm, the printing device continues the printing operation, 2. The printing apparatus according to claim 1, wherein, when the notification means issues the second alarm, the liquid passing amount detection unit causes the printing apparatus to stop a printing operation.

3. 3. The printing apparatus according to claim 1, wherein the ink passage amount detection unit detects occurrence of an abnormality in the ink passage amount based on the ink passage amount history that records the past ink passage amounts.

4. 4. The printing device according to claim 1, wherein the ink flow rate detection unit detects an occurrence of an abnormality in the ink flow rate by comparing an initial value of the ink flow rate with the current ink flow rate.

5. the ink passage amount detection unit detects whether or not there is an abnormality in the ink passage amount, 5. The printing device according to claim 1, wherein when the ink passing amount detection unit detects that the ink passing amount is abnormal, an operation of causing the inkjet head to eject ink is stopped.

6. An ink supply device that supplies ink to an inkjet head from an ink container that stores ink, a sub-tank that is a container for storing ink, the sub-tank being located in an ink supply path from the ink container to the inkjet head; a flow rate detection unit that detects an ink flow rate, which is an amount of ink flowing from the ink container to the subtank per unit time; a notification means for notifying an alarm based on the ink passing amount detected by the ink passing amount detection unit; Equipped with the ink flow amount detection unit detects the ink flow amount while a printing operation is being performed in a printing device including the inkjet head, and causes the notification unit to issue an alarm corresponding to the detected ink flow amount; The notification unit notifies at least one of the following in response to the ink flow amount detected by the ink flow amount detection unit: a first alarm indicating an abnormality in the ink flow rate while the ink supply from the ink container to the subtank can be continued; a second alarm indicating that the ink flow rate has reached a state in which the supply of ink from the ink container to the subtank should be stopped; and Inform the The liquid passing amount detection unit is when it is determined that the ink flow amount is less than a first threshold value, causing the notification means to issue the first alarm; the ink supply device being configured to cause the notification means to issue the second alarm when it is determined that the amount of ink passing through is less than a second threshold value that is smaller than the first threshold value.

7. An ink supplying method for supplying ink from an ink container that stores ink to an inkjet head, comprising the steps of: a sub-tank that is a container for storing ink is used in the middle of an ink supply path from the ink container to the inkjet head; detecting an ink flow rate, which is an amount of ink flowing from the ink container to the subtank per unit time, while a printing operation is being performed in a printing device having the inkjet head; Based on the detected ink flow rate, an alarm corresponding to the ink flow rate is issued by a notification means; The notification means notifies at least one of the following in response to the ink passing amount: a first alarm indicating an abnormality in the ink flow rate while the ink supply from the ink container to the subtank can be continued; a second alarm indicating that the ink flow rate has reached a state in which the supply of ink from the ink container to the subtank should be stopped; and Inform the when it is determined that the ink flow amount is less than a first threshold value, causing the notification means to issue the first alarm; the ink supply method further comprising causing the notification means to issue the second alarm when it is determined that the ink passing amount is less than a second threshold value that is smaller than the first threshold value.

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