Printing apparatus, ink supply apparatus, 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

[0004]

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

Background Art

[0002] Conventionally, an inkjet printer, which is a printing apparatus that performs printing by an inkjet method, has been widely used. In addition, as a configuration of an inkjet printer, a configuration in which ink is supplied from an ink container such as an ink cartridge outside an inkjet head to the inkjet head has been widely used (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When ink is supplied from an ink container outside an inkjet head to the inkjet head, an abnormality in the ink supply may affect the printing operation. In contrast, Patent Document 1 discloses setting a threshold value of the filter life in terms of the value of the ink passage amount and notifying the user. With such a configuration, for example, it is possible to prompt the replacement of the filter before a problem such as clogging of the filter occurs.

[0005] However, the timing of ink supply abnormalities can vary considerably depending on factors such as the installation environment of the printing device and variations in ink characteristics due to differences in ink manufacturing lots. Therefore, there has been a need for more flexible responses to ink supply abnormalities caused by filter clogging and other issues. Accordingly, the present invention aims 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 this invention have diligently researched methods to respond more flexibly to abnormalities in the supply of ink from the ink container to the inkjet head. More specifically, in this research, they investigated methods to appropriately avoid problems related to the sub-tank when a sub-tank is provided between the ink container and the inkjet head. They focused on the ink flow rate, which is the amount of ink flowing from the ink container to the sub-tank per unit time, and considered issuing an alarm when the ink flow rate changes. Furthermore, they considered issuing the alarm in stages according to the ink flow rate. With this configuration, for example, if an abnormality occurs in the supply of ink from the ink container to the inkjet head, the user can be appropriately notified. Moreover, by issuing the alarm in stages, it is possible to issue an alarm corresponding to the severity of the problem, for example. This also makes it possible to prompt the user to take action before a major problem occurs.

[0007] Furthermore, the inventors of this application have identified the features necessary to obtain such effects and have arrived at the present invention. In order to solve the above problems, the present invention provides a printing apparatus that performs printing by inkjet method, comprising: an inkjet head that ejects ink supplied from an ink container that stores ink; a sub-tank which is a container that stores ink in the middle of the ink supply path from the ink container to the inkjet head; an ink flow rate detection unit that detects the amount of ink that flows from the ink container to the sub-tank per unit time; and a notification means that notifies an alarm based on the ink flow rate detected by the ink flow rate detection unit, wherein the ink flow rate detection unit causes the notification means to notify a series of alarms according to the detected ink flow rate.

[0008] With this configuration, alarms are issued in stages according to the amount of ink flowing, allowing the user to be flexibly and appropriately informed of the ink supply status from the ink container to the sub-tank. Therefore, with this configuration, the user can be appropriately notified if, for example, there is an abnormality in the ink supply from the ink container to the inkjet head. Furthermore, this allows for a flexible and appropriate response to issues such as abnormalities in ink supply.

[0009] Furthermore, in this case, by providing staged notifications, it becomes possible to, for example, issue alarms according to the severity of the problem, prompting users to take action before a major problem occurs. This also makes it possible to more reliably and appropriately prompt users to take action before the printing device becomes inoperable, thereby avoiding malfunctions or preventing the spread of damage. More specifically, in this case, for example, damage to or the spread of damage to equipment related to ink supply to the sub-tank can be appropriately prevented. Therefore, with this configuration, for example, malfunctions related to the sub-tank can be appropriately prevented.

[0010] In this configuration, the notification means provides alarms using sounds and lights that appeal to the user's hearing and sight, such as voice notifications or warning displays on a screen. Regarding the notification of alarms in stages, this can be considered as providing alarms in at least two stages depending on the ink flow rate. More specifically, the notification means provides staged alarms, for example, depending on the ink flow rate detected by the ink flow rate detection unit, including a first alarm indicating an abnormality in the ink flow rate while the supply of ink from the ink container to the sub-tank is still sustainable, and a second alarm indicating that the ink flow rate has reached a state where the supply of ink from the ink container to the sub-tank should be stopped. Furthermore, the ink flow rate detection unit causes the notification means to provide the first alarm when it determines, for example, that the ink flow rate is less than a first threshold. Then, when it determines that the ink flow rate is less than a second threshold, which is smaller than the first threshold, it causes the notification means to provide the second alarm. With this configuration, for example, it is possible to appropriately notify the notification means with stepwise alarms corresponding to the amount of ink flowing. In this case, the ink flow rate detection unit may, for example, cause the notification means to notify the first alarm when it determines that the amount of ink flowing is less than a first threshold and greater than or equal to a second threshold.

[0011] Furthermore, in this configuration, the printing device performs printing using, for example, multiple inks of different colors. In this case, the printing device is equipped with, for example, an inkjet head and a sub-tank for each ink color. In this case, the ink flow rate detection unit detects the ink flow rate for each sub-tank (for each ink color). When an abnormality occurs in the ink flow rate corresponding to any sub-tank, it generates an alarm in the notification means. In this case, the ink flow rate detection unit could, for example, generate an alarm in the notification means that corresponds to the sub-tank where the ink flow rate is abnormal.

[0012] Furthermore, in this configuration, the printing apparatus may, for example, circulate ink between an ink container and a sub-tank. In this case, the ink flow rate detection unit may detect the amount of ink flowing based, for example, on the amount of ink stored in the sub-tank. More specifically, in this case, the printing apparatus further includes, for example, a supply channel which is a channel for flowing ink supplied from the ink container to the sub-tank, a circulation channel which is a channel for flowing ink returned from the sub-tank to the ink container, a supply pump which is a pump that flows the ink supplied from the ink container to the sub-tank into the supply channel, a circulation pump which is a pump that flows the ink returned from the sub-tank to the ink container into the circulation channel, and an ink amount detection unit which detects the amount of ink stored in the sub-tank. The ink flow rate detection unit then detects the amount of ink flowing based, for example, on the operating status of the supply pump and the circulation pump and the amount of ink in the sub-tank detected by the ink amount detection unit. With this configuration, for example, the amount of ink flowing can be appropriately detected.

[0013] As a sub-tank, for example, a configuration can be used that includes a first ink storage section, which is an ink storage section connected to the ink container via a supply channel, and a second ink storage section, which is an ink storage section connected to the ink container via a circulation channel. In this case, the second ink storage section is separated from the first ink storage section by a partition wall, for example. Then, ink that overflows the partition wall is supplied to the second ink storage section from the first ink storage section.

[0014] Furthermore, the printing apparatus 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 sub-tank detected by an 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 a first reference amount, and the second storage amount is less than a second reference amount, the pump control unit causes the supply pump and the circulation pump to perform an ink supply operation, for example, in which ink is supplied from the ink container to the sub-tank via the supply channel, and ink is not returned from the sub-tank to the ink container via the circulation channel. With this configuration, for example, when the amount of ink in the sub-tank becomes low, ink can be appropriately supplied from the ink container to the sub-tank.

[0015] Furthermore, if the second stored amount does not exceed the second reference amount even after a first time has elapsed since the supply pump and circulation pump started supplying ink, the ink flow rate detection unit determines, for example, that the ink flow rate is less than the first threshold. Moreover, if the second stored amount does not exceed the second reference amount even after a second time has elapsed, which is longer than the first time, since the supply pump and circulation pump started supplying ink, the ink flow rate detection unit determines, for example, that the ink flow rate is less than the second threshold, which is smaller than the first threshold. With this configuration, for example, the ink flow rate can be detected appropriately.

[0016] Furthermore, in this configuration, the ink flow rate detection unit may, for example, detect the occurrence of an abnormality in the ink flow rate based on the history of ink flow rates, which records past ink flow rates. With this configuration, for example, abnormalities in the ink flow rate can be detected more appropriately. In this case, the ink flow rate detection unit may, for example, detect the abnormality in the ink flow rate by comparing the initial value of the ink flow rate with the current ink flow rate, or by based on changes in the ink flow rate over time.

[0017] Furthermore, in this configuration, the printing apparatus may also include a filter that passes the ink through in the flow path for the ink supplied from the ink container to the sub-tank. In this case, the ink flow rate detection unit detects, for example, whether or not there is an abnormality in the ink flow rate. If the ink flow rate detection unit detects that the ink flow rate is abnormal, it is conceivable to reduce the amount of ink supplied from the ink container to the sub-tank so that the flow rate of ink passing through the filter is reduced. With this configuration, for example, if an abnormality in the ink flow rate occurs due to filter clogging, it is possible to appropriately prevent an amount of ink that cannot pass through the filter from being supplied to the filter.

[0018] Furthermore, if the printing device is equipped with a supply channel and a circulation channel, and the ink flow rate detection unit detects that the ink flow rate is abnormal, it is conceivable that the operation of returning ink from the sub-tank to the ink container via the circulation channel may be stopped. With this configuration, for example, if the amount of ink supplied from the ink container to the sub-tank decreases, it is possible to appropriately prevent the ink in the sub-tank from running out in a short time. Also, if the ink flow rate detection unit detects that the ink flow rate is abnormal, it is conceivable that the operation of ejecting ink to the inkjet head may be stopped. With this configuration, for example, it is possible to appropriately prevent the inkjet head or printing device from malfunctioning due to continuing printing operations when there is an abnormality in the ink flow rate.

[0019] Furthermore, the present invention can also be considered to include configurations such as ink supply devices and ink supply methods having the same characteristics as described above. In these cases as well, for example, the same effects as described above can be obtained. [Effects of the Invention]

[0020] According to the present invention, for example, it is possible to respond flexibly and appropriately to abnormalities in ink supply, etc. [Brief explanation of the drawing]

[0021] [Figure 1] It is a diagram showing an example of the configuration of the main part of the printing apparatus 100 according to an embodiment of the present invention. [Figure 2] It is a diagram for explaining a more specific configuration and the like of the ink supply system 108. FIG. 2(a) shows an example of the configuration of the ink supply system 108. FIG. 2(b) shows an example of the configuration of the sub-tank 202 in the ink supply system 108. [Figure 3] It is a diagram for explaining in more detail the control and the like performed by the control unit 120. FIG. 3(a) shows an example of the functional configuration of the control unit 120. FIG. 3(b) shows an example of the control performed by the pump control unit 404. [Figure 4] It is a flowchart showing an example of the operation of the liquid flow rate detection unit 410.

Mode for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an example of the configuration of the main part of the printing apparatus 100 according to an embodiment of the present invention. In this example, the printing apparatus 100 is an inkjet printer that performs printing on a medium (media) 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 scanning drive unit 112, a maintenance unit 114, a notification unit 116, and a control unit 120. Except for the points described below, the printing apparatus 100 may have the same or similar features as a known inkjet printer. For example, the printing apparatus 100 may further include the same or similar configuration as a known inkjet printer in addition to the configuration shown in FIG. 1. Also, in this example, the printing apparatus 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, each of the multiple inkjet heads 102 ejects ink of a different color from each other. Each inkjet head 102 also has multiple nozzles, and ejects ink from each nozzle according to the image to be printed. The platen 104 is a platform-shaped member that holds the medium 50 opposite the multiple inkjet heads 102.

[0024] The multiple main tanks 106 are ink containers that store ink to be supplied to the multiple inkjet heads 102. In this example, each of the multiple main tanks 106 stores ink of a different color, and supplies ink to any of the inkjet heads 102 via the ink supply system 108. Suitable main tanks 106 include, for example, ink bottles and ink cartridges. In this example, the main tanks 106 are ink containers that can be refilled. In this case, the ink to be refilled in the ink supply system 108 can be done, for example, while the main tanks 106 remain installed in the printing device 100. Alternatively, the main tanks 106 could be, for example, ink containers that can be removed from the printing device 100 and replaced. In this case, the main tanks 106 can be considered, for example, components other than those of the printing device 100.

[0025] The ink supply system 108 includes an ink supply path that supplies ink from multiple main tanks 106 to multiple inkjet heads 102. In this example, the ink supply system 108 includes a sub-tank that stores ink between the main tanks 106 and the inkjet heads 102, and a filter that allows the ink supplied from the main tanks 106 to the sub-tank to pass through. A more detailed explanation of the specific configuration of the ink supply system 108 will be given later. The carriage 110 is a holding member that holds multiple inkjet heads 102. In this example, the carriage 110 also holds a part of the ink supply system 108 together with the multiple inkjet heads 102. More specifically, in this example, the carriage 110 holds the sub-tank and the like in the ink supply system 108. With this configuration, for example, the sub-tank can be appropriately installed near the inkjet heads 102.

[0026] The scanning drive unit 112 is a drive unit that causes multiple inkjet heads 102 to perform scanning operations that move relative to the medium 50. In this example, the scanning drive unit 112 causes the multiple inkjet heads 102 to perform main scanning operations and sub-scanning operations. In this case, the main scanning operation can be considered, for example, an operation in which ink is ejected while moving relative to the medium 50 in a predetermined main scanning direction. In the main scanning operation, the scanning drive unit 112 causes the multiple inkjet heads 102 to eject ink to an ink ejection position selected according to the image to be printed. The sub-scanning operation can be considered, for example, an operation in which the inkjet heads move relative to the medium 50 in a sub-scanning direction perpendicular to the main scanning direction. The scanning drive unit 112 changes the range on the medium 50 that is facing the multiple inkjet heads 102 by causing the multiple inkjet heads 102 to perform sub-scanning operations in between main scanning operations. Furthermore, this causes the scanning drive unit 112 to have multiple inkjet heads 102 eject ink to various positions on the medium 50.

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

[0028] The notification unit 116 is configured to notify the user of the printing device 100 of various types of information. In this example, the notification unit 116 is an example of a notification means, and it notifies alarms using sound and light that appeal to the user's hearing and sight, such as voice notifications or warning displays on the display. In this case, for example, the speaker and display in the printing device 100 can be considered to correspond to the notification unit 116. In this example, the notification unit 116 also notifies alarms regarding abnormalities in the supply of ink from the main tank 106 to the sub-tanks of the ink supply system 108. In this case, the notification unit 116 also notifies alarms 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 explained in more detail later.

[0029] The control unit 120 is, for example, a part of the printing device 100 that includes the CPU, and controls the operation of each part of the printing device 100 according to a program (for example, firmware) that controls the operation of the printing device 100. In this case, for example, the operation of the control unit 120 can be realized by the CPU, etc., having various functional configurations according to the program. Also, 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 explained in more detail later.

[0030] Next, we will explain in more detail the specific configuration of the ink supply system 108 in the printing device 100. Figure 2 is a diagram illustrating the specific configuration of the ink supply system 108. Figure 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 multiple inkjet heads 102 in the printing device 100. In this example, the ink supply system 108 has a sub-tank 202, a supply channel 204, a circulation channel 206, multiple pumps 212, 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 device 100 has, for example, a sub-tank 202, a supply channel 204, and a circulation channel 206 for each ink color.

[0031] The sub-tank 202 is an ink container that stores ink along the ink supply path from the main tank 106 to the inkjet head 102. In this example, the sub-tank 202 is held together with the inkjet head 102 in the carriage 110 (see Figure 1), so that it stores ink in a smaller volume than the main tank 106 near the inkjet head 102. Furthermore, the internal pressure of the sub-tank 202 is adjusted to a negative pressure relative to atmospheric pressure by an adjustment mechanism, for example, which is not shown in Figure 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, for example, ink from leaking out of the nozzles of the inkjet head 102.

[0032] Furthermore, in a modified version of the ink supply system 108, the space inside the sub-tank 202 may be open to the atmosphere, for example. In this case, the pressure inside the sub-tank 202 can be considered to be equal to the atmospheric pressure. In this case, for example, a pressure adjustment unit (e.g., a pressure damper) can be further provided between the sub-tank 202 and the inkjet head 102 to adjust the ink supply pressure to the inkjet head 102. This pressure adjustment unit adjusts the pressure of the ink supplied to the inkjet head 102 to a negative pressure relative to atmospheric pressure by, for example, lowering the pressure of the ink supplied from the sub-tank 202, which is at a supply pressure corresponding to atmospheric pressure, by a predetermined adjustment amount. Even with this configuration, for example, ink can be supplied to the inkjet head 102 appropriately.

[0033] The supply channel 204 is a channel through which ink supplied from the main tank 106 to the sub-tank 202 flows. For example, a tube for passing ink can be suitably used as the supply channel 204. In this example, the supply channel 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 channel 206 is an ink channel for circulating ink between the main tank 106 and the sub-tank 202, and flows ink through a different path than the supply channel 204 to return ink from the sub-tank 202 to the main tank 106. For example, a tube for passing ink can also be suitably used as the circulation channel 206. The pump 212 is an example of a supply pump, and it flows the ink supplied from the main tank 106 to the sub-tank 202 into the supply channel 204. Pump 214 is an example of a circulation pump, and it flows the ink that is returned from the sub-tank 202 to the main tank 106 into the circulation channel 206. For pumps 212 and 214, for example, known tube pumps can be suitably used.

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

[0035] In this example, the control unit 120 (see Figure 1) of the printing apparatus 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 when such control is performed. 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 a plurality of liquid level detection sensors 306, 308, as shown in Figure 2(b). Figure 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 a supply channel 204 to store the 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 a circulation channel 206 to store the ink that is sent to the main tank 106 during ink circulation.

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

[0038] With the above configuration, in the sub-tank 202 of this example, the ink supplied from the main tank 106 is first supplied to the IN side storage section 302. When a sufficient amount of ink has accumulated in the IN side storage section 302 and the liquid level exceeds the height of the partition wall 300, the ink overflowing from 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 has accumulated 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 channel 206. According to this example, for example, ink can be appropriately supplied from the main tank 106 to the sub-tank 202, and ink can be appropriately circulated between the main tank 106 and the sub-tank 202.

[0039] In this example, ink is also circulated between the inkjet head 102 and the sub-tank 202. In this case, the supply of ink from the sub-tank 202 to the inkjet head 102 is performed from the IN side storage unit 302, for example, as shown in the figure. The OUT side storage unit 304 receives the ink returning from the inkjet head 102. Therefore, in this example, the supply of ink from the IN side storage unit 302 to the OUT side storage unit 304 is performed not only by the path overflowing the partition wall 300, but also by the path via the inkjet head 102. Furthermore, in this example, the amount of ink in the sub-tank 202 is detected by multiple liquid level detection sensors 306 and 308 in the sub-tank 202, and the control unit 120 controls the operation of multiple pumps 212 and 214, etc., based on the results, thereby controlling the supply and circulation of ink. The functional configuration of the control unit 120 and the control of ink supply and circulation performed by the control unit 120 will be explained in more detail below.

[0040] Figure 3 is a diagram that further explains the control and other functions performed by the control unit 120. Figure 3(a) is a diagram showing an example of the functional configuration of the control unit 120, illustrating an example of the configuration of the control unit 120 using functional blocks that represent the control and other functions performed by the control unit 120. Figure 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 scanning control unit 402, a pump control unit 404, a maintenance control unit 406, an ink volume detection unit 408, a liquid flow rate 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, the CPU etc. included in the control unit 120 functions as the scanning control unit 402, pump control unit 404, maintenance control unit 406, ink volume detection unit 408, and liquid flow rate detection unit 410 by operating according to a program such as firmware. Also, for example, the CPU etc. included in the control unit 120 functions as the storage unit 412 together with storage means such as memory or storage. In addition to the above configuration, the control unit 120 may further have other functional configurations corresponding to the operations performed by the printing device 100.

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

[0043] Furthermore, the ink level detection unit 408 detects the amount of ink stored in the sub-tank 202. More specifically, in this example, the ink level detection unit 408 detects a first storage amount, which is the amount of ink stored in the IN side storage unit 302 (see Figure 2), based on the output of the liquid level detection sensor 306 (see Figure 2) in the sub-tank 202. It also detects a second storage amount, which is the amount of ink stored in the OUT side storage unit 304 (see Figure 2), based on the output of the liquid level detection sensor 308 (see Figure 2) in the sub-tank 202. In this case, the liquid level detection sensors 306 and 308 can be considered to be located outside the control unit 120, for example. However, if the configuration of the printing device 100 or the part considered to be the control unit 120 is different, the sensors such as the liquid level detection sensors 306 and 308 can also be considered to be part of the control unit 120.

[0044] The ink flow rate detection unit 410 detects the amount of ink flowing per unit time from the main tank 106 (see Figure 1) to the sub-tank 202. In this example, the ink flow rate detection unit 410 detects the ink flow rate based on the operating status of 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 ink flow rate detection unit 410 also determines whether there is an abnormality in the ink flow rate, and if an abnormality occurs, it causes the notification unit 116 (see Figure 1) to sound an alarm. The ink flow rate detection unit 410 can also be considered, for example, as an example of a means for determining whether there is an abnormality in the ink flow rate. The method of detecting the ink flow rate by the ink flow rate detection unit 410 and the operation of causing the notification unit 116 to sound an alarm will be explained in more detail later. The storage unit 412 stores and manages the parameters used for control performed by the control unit 120. In this example, the memory unit 412 also stores a history of ink flow rates, which is a record of past ink flow rates. The use of this ink flow rate history will be explained in more detail later.

[0045] Next, as an example of control performed by the control unit 120, we will explain the control of the pump operation performed by the pump control unit 404. Furthermore, in the following, the operation of the functional configuration of the control unit 120, such as the pump control unit 404, will be simply described as the operation of its configuration. As explained above, in this example, the pump control unit 404 controls the operation of the pumps 212 and 214 in the ink supply system 108 based on the first and second storage amounts, which are the amounts of ink in the sub-tank 202 detected by the ink amount detection unit 408.

[0046] More specifically, in this example, the ink level detection unit 408 detects which of the five levels—Low, Middle, High, Near Full, and Limit—corresponds to the liquid level in the IN side storage unit 302 (IN side liquid level) for the first storage amount. Similarly, for the second storage amount, it detects which of the five levels—Low, Middle, High, Near Full, and Limit—corresponds to the liquid level in the OUT side storage unit 304 (OUT side liquid level). In this case, Low indicates the lowest storage amount, and the storage amounts increase in the order of Middle, High, Near Full, and Limit. Furthermore, the storage amounts that correspond to each level are individually set for the liquid level detection sensors 306 and 308, respectively, according to the height at which they are installed. For example, the ink quantity detection unit 408 detects the first storage amount based on multiple reference amounts set according to multiple different liquid level positions at positions close to the height of the partition wall 300 (see Figure 2) separating the IN side storage unit 302 and the OUT side storage unit 304. The ink quantity detection unit 408 also detects the second storage amount based on multiple reference amounts set according to multiple different liquid level positions at predetermined positions lower than the height of the partition wall 300.

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

[0048] Furthermore, the pump control unit 404 adjusts the amount of ink stored in the IN-side storage unit 302 and the OUT-side storage unit 304, respectively, by causing the pumps 212 and 214 to perform these operations, so that the amount of ink stored in each of them is one of states A, B, or C shown in Figure 3(b). In this case, states A, B, and C are determined according to the relationship between the reference amounts Li1 and Li2 shown in the figure and the first storage amount, and the relationship between the reference amounts Lo1 and Lo2 and the second storage amount. In this example, reference amount Li2 is an example of the first reference amount. Reference amount Lo1 is an example of the second reference amount. State A 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 less than the reference amount Lo1. Also, in the case shown in the figure, the second storage amount in state A is less than the reference amount Lo1 and greater than or equal to the reference amount Lo2. State B can be considered, for example, as a state where the first storage volume is less than the standard amount Li2, and the second storage volume is equal to or greater than the standard amount Lo1. State C can be considered, for example, as a state where the first storage volume is equal to or greater than the standard amount Li2, and the second storage volume is equal to or greater than the standard amount Lo1. In the case shown in the figure, the first storage volume in state C is equal to or greater than the standard amount Li2, and less than the standard amount Li1.

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

[0050] In this example, to ensure adequate ink supply capacity, the capacity of the ink supply pump 212 is set to be greater than that of the circulation pump 214. Therefore, during normal operation, transitions mainly occur between states B and C among states A, B, and C. In this case, for example, when ink consumption increases, the amount of ink in the sub-tank 202 decreases, causing a transition to state A, thereby allowing the sub-tank 202 to supply ink appropriately. This also maintains the transition between states A, B, and C regarding the amount of ink stored in the sub-tank 202, as described above.

[0051] Furthermore, if, for example, the amount of ink consumed changes significantly temporarily, or if there is an abnormality in the supply or circulation of ink, the amount of ink stored in the sub-tank 202 may be in a state other than states A, B, or C. Therefore, in this example, as shown in parentheses in the figure, the ink supply operation, ink supply and circulation operation, or ink circulation operation is associated with states other than states A, B, and C. In this case, for some states, other operations may be associated with them. In addition, such associations between states and operations can 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 as controlling the operation of 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 sub-tank 202 and the circulation of ink can be performed appropriately.

[0052] Next, we will explain in more detail how the ink flow rate detection unit 410 detects the amount of ink flowing, and how it causes the notification unit 116 (see Figure 1) to issue an alarm. As explained above, in this example, the ink flow rate detection unit 410 determines whether there is an abnormality in the amount of ink flowing from the main tank 106 to the sub-tank 202, and if an abnormality occurs, it causes the notification unit 116 to issue an alarm. In this case, the ink flow rate detection unit 410 detects the amount of ink flowing based on the operating status 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 Figure 4. Then, it causes the notification unit 116 to issue at least two stages of gradual alarms according to the amount of ink flowing.

[0053] Figure 4 is a flowchart showing an example of the operation of the liquid flow rate detection unit 410, illustrating an example of the operation of the liquid flow rate detection unit 410 after the ink storage amount in the sub-tank 202 has reached state A. In this example, when the amount of ink flowing from the main tank 106 to the sub-tank 202 decreases, the liquid flow rate detection unit 410 first notifies the notification unit 116 of a warning level alarm. Then, when the amount of ink flowing decreases further, it notifies the notification unit 116 of an error level alarm. In this case, the warning level alarm is an example of a first alarm indicating an abnormality in the amount of ink flowing while it is still possible to continue supplying ink from the main tank 106 to the sub-tank 202. The warning level alarm can also be thought of as, for example, an alarm to alert the user while printing is in progress. The error level alarm is an example of a second alarm indicating that the amount of ink flowing has reached a state where the supply of ink from the main tank 106 to the sub-tank 202 should be stopped. Error level alarms can be thought of as, for example, alarms indicating that the printing device 100 (see Figure 1) is inoperable, or alarms that notify when the ink supply to the sub-tank 202 is stopped (interrupted).

[0054] As explained above, during normal operation in this example, the state of the ink storage amount in the sub-tank 202 mainly transitions between states B and C as described above. However, if the amount of ink flowing from the main tank 106 to the sub-tank 202 decreases due to, for example, clogging of the filter 218 (see Figure 2) in the supply channel 204 (see Figure 2), the state of the ink storage amount in the sub-tank 202 changes to state A. In this case, if the decrease in the amount of ink flowing is minor, the state of the ink storage amount in the sub-tank 202 will return to state B in a short time. On the other hand, if the amount of ink flowing decreases more significantly, it is possible that the time to return to state B will be longer, or that it may not be possible to return to state B at all. Therefore, in this example, the ink flow rate detection unit 410 detects the amount of ink flowing based on the elapsed time after the ink storage amount in the sub-tank 202 reaches state A.

[0055] More specifically, in the operation of the flowchart shown in Figure 4, the liquid flow rate detection unit 410 checks whether a change to state B has occurred, for example, after a predetermined time has elapsed since state A was reached (S102). In this example, the change from state A to state B can be understood, for example, from the items shown in Figure 3(b), as it corresponds to the second storage amount in the sub-tank 202 becoming equal to or greater than the standard amount Lo1. Then, in step S102, if it is determined that a change from state A to state B has occurred (S102: Yes), the liquid flow rate detection unit 410 terminates its operation of detecting the ink flow rate.

[0056] Furthermore, if it is determined in step S102 that the state has not changed to state B (S102: No), the elapsed time since state A is reached 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. The elapsed time since state A is reached can be considered, for example, the time since pumps 212 and 214 started the ink supply operation in response to the control of the pump control unit 404. If, in this comparison, 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] Furthermore, in this comparison, if the elapsed time exceeds time T1 (S104: Yes) and has not reached time T2 (S106: No), the ink flow rate detection unit 410 determines that the ink flow rate is less than the first threshold F1 (S108). Based on this determination, the ink flow rate detection unit 410 executes an ink flow rate warning process, which is performed when the ink flow rate decreases to a warning level (S110). More specifically, in this example, the ink flow rate detection unit 410 causes the notification unit 116 to notify an alarm indicating a warning level as part of the ink flow rate warning process. Also in this example, the printing device 100 continues printing even after the warning level alarm is notified. Therefore, after performing the ink flow rate warning process, the ink flow rate detection unit 410 returns to step S102 and repeats the subsequent operations.

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

[0059] With this configuration, for example, the amount of ink flowing can be appropriately detected based on the elapsed time after the ink storage amount in the sub-tank 202 reaches state A. Furthermore, by detecting the relationship between the two thresholds F1 and F2 and the amount of ink flowing, the notification unit 116 can appropriately issue stepwise alarms. This also makes it possible to issue alarms according to the magnitude of the problem occurring, prompting the user to take action before a major problem occurs. Therefore, according to this example, for example, if there is an abnormality in the supply of ink from the main tank 106 to the inkjet head 102 (see Figure 1) via the sub-tank 202, the user can be appropriately notified. Furthermore, this makes it possible to respond more flexibly and appropriately to abnormalities in ink supply, for example. More specifically, it makes it possible to more reliably and appropriately prompt the user to take action before the printing device becomes inoperable, thereby avoiding the occurrence of malfunctions and preventing the spread of damage.

[0060] Furthermore, as described above, in this example, the liquid flow rate detection unit 410 stops the supply of ink from the main tank 106 to the sub-tank 202 during liquid flow rate error processing. With this configuration, for example, it is possible to prevent the occurrence of unexpected damage or the escalation of damage, and to more appropriately enhance the safety of the operation of the printing device 100. More specifically, in this case, for example, it is possible to appropriately prevent damage or the escalation of damage to equipment related to the supply of ink to the sub-tank 202. In addition, this makes it possible to appropriately prevent the occurrence of malfunctions related to the sub-tank 202, for example.

[0061] Next, we will provide supplementary explanations regarding the configuration described above, as well as explanations of modified examples. As explained above, in this example, the printing apparatus 100 has each component, such as the sub-tanks 202 used to supply ink from the main tank 106 to the inkjet head 102, for each ink color. Therefore, in this example, the ink flow rate detection unit 410 detects the amount of ink flowing through each sub-tank 202 corresponding to each color of ink. Furthermore, if an abnormality occurs in the amount of ink flowing through any of the sub-tanks 202, the ink flow rate detection unit 410 generates an alarm in the notification unit 116, for example, by associating it with the sub-tank 202 in which the ink flow rate is abnormal. In this case, the notification unit 116 may, for example, generate an alarm while indicating the sub-tank 202 in which the abnormality is occurring.

[0062] Furthermore, in this example, possible causes for a decrease in ink flow rate include, for example, clogging of the filter 218 in the supply channel 204. Therefore, detecting an abnormality in the ink flow rate in the supply channel 204 can be considered as, for example, detecting 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 stepwise alarm, it becomes possible to prompt the user to take action, such as replacing the filter 218, before the filter 218 becomes completely clogged and inoperable. In this regard, if the filter 218 becomes completely clogged and inoperable, it is not only impossible to perform printing operations, but it is also possible that maintenance operations (cleaning) such as purging and flushing cannot be performed by the maintenance unit 114 (see Figure 1). As a result, damage to the inkjet head 102 may occur. In contrast, according to this example, it becomes possible to appropriately prevent damage to the inkjet head 102, for example, by detecting an abnormality in the amount of ink flowing before the printing device 100 becomes inoperable due to clogging of the filter 218 or the like.

[0063] Furthermore, in addition to clogging of the filter 218, other possible causes of a decrease in ink flow rate include ink leakage due to damage to tubes constituting the supply channel 204, or malfunctions such as failure of the pump 212 that prevent ink from being supplied to the sub-tank 202. Additionally, malfunctions of the liquid level detection sensors 306 and 308 may lead to false detections, where ink is actually being supplied to the sub-tank 202 but the system fails to detect it correctly. In contrast, this example allows for appropriate alarm notification and prompts the user to take action even when deviations from the control range occur due to various reasons as described above.

[0064] Furthermore, as mentioned above, the main tank 106 could be, for example, an ink container that can be refilled with ink. Also, as mentioned above, the pressure inside the sub-tank 202 is adjusted so that ink can be supplied to the inkjet head 102 at the appropriate pressure. However, if the amount of ink in the sub-tank 202 decreases due to, for example, ink consumption by the inkjet head 102, the negative pressure value may increase as the space inside the sub-tank 202 relatively increases. In this case, for example, the space inside the sub-tank 202 may be opened to the atmosphere in order to adjust to the appropriate pressure. In this case, for example, the ink may deteriorate due to exposure to air, which could easily cause clogging of the filter 218. Moreover, in a configuration in which ink is circulated between the main tank 106 and the sub-tank 202, as in this example, the repeated passage of ink through the filter 218 could easily cause clogging of the filter 218. In contrast, according to this example, it becomes possible to prompt the user to take action such as replacing the filter 218 before the filter 218 becomes completely clogged and inoperable, as described above. Therefore, according to this example, even when using a configuration in which the filter 218 is prone to clogging, it is possible to more effectively prevent major problems such as damage to the inkjet head 102.

[0065] Furthermore, the actions taken when an abnormality in the ink flow rate is detected are not limited to those described above and can be modified in various ways. For example, in the operation shown in the flowchart in Figure 4, the ink flow rate detection unit 410 will notify the notification unit 116 of a warning level alarm when it determines that the ink flow rate is less than the first threshold F1 and greater than or equal to the second threshold F2. Therefore, when the ink flow rate decreases, the ink flow rate detection unit 410 will notify the notification unit 116 of either the warning level or the error level, depending on the ink flow rate. In contrast, in a modified example of the operation when an abnormality in the ink flow rate occurs, the ink flow rate detection unit 410 may notify the notification unit 116 of both the warning level and the error level alarm when, for example, the ink flow rate falls below the second threshold F2.

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

[0067] Furthermore, as can be understood from the operation of the transitions between states A, B, and C explained using Figure 3(b), 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 falls below a predetermined amount, based on the output of the liquid level detection sensor 308. Therefore, if the amount of ink flowing becomes small, resulting in an abnormal state where the amount of ink supplied to the sub-tank 202 is insufficient, the pump control unit 404 controls the operation of pumps 212 and 214 to perform the ink circulation operation intermittently. In contrast, in a modified example of the operation when an abnormality in the amount of ink flowing occurs, it is conceivable that when the amount of ink flowing detection unit 410 detects that the amount of ink flowing is abnormal, the ink circulation operation may be stopped directly in response to that detection. Such control can be considered, for example, as control that prohibits the operation of returning ink from the sub-tank 202 to the main tank 106 via the circulation channel 206 when an abnormality in the amount of ink flowing occurs. With this configuration, for example, if 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. This control of ink circulation can also be performed, for example, while the printing operation continues when the ink flow rate warning process is executed. With this configuration, for example, even if an abnormality occurs in the ink flow rate, the printing operation can be continued more appropriately.

[0068] As explained above, in this example, when an ink flow rate error is executed, the printing operation of the printing device 100 is stopped. This also stops the operation of ejecting ink to the inkjet head 102. In contrast, in a modified version of the operation when an abnormality in the ink flow rate occurs, for example, it is conceivable that the operation of ejecting ink to the inkjet head 102 is also stopped when an ink flow rate warning process is executed. In this case, the ink flow rate detection unit 410 stops the operation of ejecting ink to the inkjet head 102 corresponding to the sub-tank 202 in response to detecting an abnormality in the ink flow rate to any of the sub-tanks 202. With this configuration, for example, it is possible to appropriately prevent the ink in the sub-tanks 202 and inkjet head 102 from running out by continuing the printing operation when an abnormality in the ink flow rate occurs. Furthermore, this also appropriately prevents the inkjet head 102 and printing device 100 from malfunctioning even when an abnormality in the ink flow rate occurs.

[0069] As explained above, in this example, the relationship between the amount of ink flowing and the first and second thresholds F1 and F2 is determined by comparing the elapsed time since state A was reached with preset times T1 and T2. More specifically, the above explanation described the method of detecting the amount of ink flowing, mainly based on the output of the liquid level detection sensors 306 and 308 in the sub-tank 202 and the operating status of the pumps 212 and 214. With this configuration, for example, the amount of ink flowing can be detected appropriately at a low cost. However, the method of detecting the amount of ink flowing is not limited to the above and can be changed in various ways. For example, it is also possible to install a liquid level sensor in the supply channel 204 and detect the amount of ink flowing based on the output of the liquid level sensor. With this configuration, for example, the amount of ink flowing can be detected appropriately with high accuracy.

[0070] Furthermore, the amount of ink flowing may change gradually over time, for example. More specifically, if the amount of ink flowing decreases due to clogging of the filter 218, the amount of ink flowing may gradually decrease according to the operating time of the printing device 100. In contrast, in this example, as explained above, the memory unit 412 stores the history of the amount of ink flowing. In this case, the ink flow rate detection unit 410 may, for example, detect the occurrence of an abnormality in the amount of ink flowing based on the history of the amount of ink flowing. Also, in this case, for example, in addition to detecting the amount of ink flowing using the method explained above, the history of the amount of ink flowing may be further utilized. With this configuration, for example, abnormalities in the amount of ink flowing can be detected more appropriately. Also, in this case, the ink flow rate detection unit 410 may, for example, detect an abnormality in the amount of ink flowing by comparing the initial value of the amount of ink flowing with the current amount of ink flowing, or by the time-series change in the amount of ink flowing.

[0071] In this case, for example, a threshold could be set to determine an abnormality in the ink flow rate based on past ink flow rates under normal conditions. More specifically, in this case, for example, a threshold for the ink flow rate could be set based on the ink flow rate at the time of shipment, maintenance, or start of printing operation on the printing device 100. Also, for example, when detecting an abnormality in the ink flow rate by the same or similar operation as shown in the flowchart in Figure 4, the time intervals T1 and T2, which are compared with the elapsed time since state A was reached, could be set based on the history of the ink flow rate.

[0072] Furthermore, in the above, the configuration of the printing device 100 was mainly described in the case where ink is ejected onto a medium. In this case, the printing device 100 can be considered as an inkjet printer or the like that draws a two-dimensional image on the medium. In contrast, in a modified configuration of the printing device 100, it is also possible to use, for example, a 3D printer (3D printing device) that creates three-dimensional objects as the printing device 100. In this case, the build plate that supports the object being created and the object being created can be considered as the target from which ink is ejected. In this case as well, by providing alarm notifications in the same manner as above, it is possible to respond more flexibly and appropriately to abnormalities in ink supply, etc. [Industrial applicability]

[0073] The present invention can be suitably used, for example, in printing devices and the like. [Explanation of symbols]

[0074] 50... Media, 100... Printing device, 102... Inkjet head, 104... Platen, 106... Main tank, 108... Ink supply system, 110... Carriage, 112... Scanning drive unit, 114... Maintenance unit, 116... Notification unit, 120... Control unit, 202... Sub-tank, 204... Supply channel, 206... Circulation channel, 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 volume detection section, 410... Liquid flow rate detection section, 412... Memory section

Claims

1. A printing apparatus that performs printing using an inkjet method, An inkjet head that ejects ink supplied from an ink container that stores ink, A sub-tank, which is a container for storing ink, is located in the middle of the ink supply path from the ink container to the inkjet head. A liquid flow rate detection unit detects the amount of ink flowing per unit time from the ink container to the sub-tank, Notification means for notifying an alarm based on the ink flow rate detected by the ink flow rate detection unit. Equipped with, The ink flow rate detection unit detects the amount of ink flowing while the printing operation is in progress, and causes the notification means to notify an alarm corresponding to the detected amount of ink flowing. The notification means, in accordance with the amount of ink flow detected by the amount of ink flow detection unit, at least: A first alarm indicating an abnormality in the amount of ink flowing while the supply of ink from the ink container to the sub-tank can continue, A second alarm indicates that the ink flow rate has reached a state where the supply of ink from the ink container to the sub-tank should be stopped. To report, The aforementioned liquid flow rate detection unit is If it is determined that the amount of ink flowing is less than the first threshold, the notification means will sound the first alarm. A printing apparatus characterized in that, when it is determined that the amount of ink flowing is less than a second threshold which is smaller than the first threshold, the notification means is made to sound the second alarm.

2. When the liquid flow rate detection unit causes the notification means to notify the first alarm, the printing device continues the printing operation. The printing apparatus according to claim 1, characterized in that when the notification means is caused to notify the second alarm, the liquid flow rate detection unit causes the printing apparatus to stop printing.

3. The printing apparatus according to claim 1 or 2, characterized in that the ink flow rate detection unit detects the occurrence of an abnormality in the ink flow rate based on the history of the ink flow rate, which records the past ink flow rates.

4. The printing apparatus according to any one of claims 1 to 3, characterized in that the ink flow rate detection unit detects the occurrence of an abnormality in the ink flow rate by comparing the initial value of the ink flow rate with the current ink flow rate.

5. The ink flow rate detection unit detects whether or not there is an abnormality in the ink flow rate, The printing apparatus according to any one of claims 1 to 4, characterized in that when the ink flow rate detection unit detects that the amount of ink flow is abnormal, the operation of ejecting ink from the inkjet head is stopped.

6. An ink supply device that supplies ink from an ink container that stores ink to an inkjet head, A sub-tank, which is a container for storing ink, is located in the middle of the ink supply path from the ink container to the inkjet head. A liquid flow rate detection unit detects the amount of ink flowing per unit time from the ink container to the sub-tank, Notification means for notifying an alarm based on the ink flow rate detected by the ink flow rate detection unit. Equipped with, The ink flow rate detection unit detects the amount of ink flowing while the printing operation is being performed in the printing apparatus equipped with the inkjet head, and causes the notification means to notify an alarm corresponding to the detected amount of ink flowing. The notification means, in accordance with the amount of ink flow detected by the amount of ink flow detection unit, at least: A first alarm indicating an abnormality in the amount of ink flowing while the supply of ink from the ink container to the sub-tank can continue, A second alarm indicates that the ink flow rate has reached a state where the supply of ink from the ink container to the sub-tank should be stopped. To report, The aforementioned liquid flow rate detection unit is If it is determined that the amount of ink flowing is less than the first threshold, the notification means will sound the first alarm. An ink supply device characterized in that, when it is determined that the amount of ink flowing is less than a second threshold which is smaller than the first threshold, the notification means is made to sound the second alarm.

7. An ink supply method for supplying ink from an ink container that stores ink to an inkjet head, A sub-tank, which is a container for storing ink, is used in the middle of the ink supply path from the ink container to the inkjet head. In a printing apparatus equipped with the aforementioned inkjet head, while the printing operation is in progress, the amount of ink flowing from the ink container to the sub-tank per unit time is detected, Based on the detected amount of ink flowing, the notification means is made to issue an alarm corresponding to the amount of ink flowing. The notification means, depending on the amount of ink flowing, at least, A first alarm indicating an abnormality in the amount of ink flowing while the supply of ink from the ink container to the sub-tank can continue, A second alarm indicates that the ink flow rate has reached a state where the supply of ink from the ink container to the sub-tank should be stopped. To report, If it is determined that the amount of ink flowing is less than the first threshold, the notification means will sound the first alarm. An ink supply method characterized in that, when it is determined that the amount of ink flowing is less than a second threshold which is smaller than the first threshold, the notification means is made to sound the second alarm.

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