Ink jet printer and control method of ink jet printer

Abstract

To provide an ink jet printer capable of objectively grasping a state of an ink filter in the ink jet printer including the ink filter arranged in a supply path of ink to an ink jet head.SOLUTION: In an ink jet printer 1, ink passing through an ink filter 15 is made to flow from a buffer tank 12 to a main tank 13 by driving a pump 14 at constant speed for a fixed time in a state that ink is prevented from flowing from the main tank 13 to the buffer tank 12 by closing a first pipe path 19 for connecting the main tank 13 and the buffer tank 12, and an increase amount of ink in the main tank 13 after driving the pump 14 from an amount of ink in the main tank 13 before driving the pump 14 is calculated on the basis of a detection result of a detection mechanism 16.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an inkjet printer for printing on a medium such as paper. The present invention also relates to a control method for such an inkjet printer.

Background Art

[0002] Conventionally, an inkjet printer for printing on a medium such as paper has been known (see, for example, Patent Document 1). The inkjet printer described in Patent Document 1 includes an inkjet head that discharges ink, a carriage on which the inkjet head is mounted, a sub-tank that stores ink supplied to the inkjet head, a main tank that stores ink supplied to the sub-tank, and an ink pump for sending ink from the main tank to the sub-tank. Further, the inkjet printer described in Patent Document 1 includes an ink filter (filter) disposed in a piping path between the pump and the sub-tank. The ink filter functions to remove foreign substances in the ink supplied to the sub-tank.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the inkjet printer described in Patent Document 1, when the ink filter becomes clogged and ink is not sufficiently supplied from the main tank to the sub-tank, there is a risk of problems such as the supply of ink to the inkjet head becoming insufficient and printing being forced to stop. To prevent the occurrence of this problem, the ink filter may be replaced regularly. However, the state of the ink filter changes according to the usage conditions of the inkjet printer. That is, if the amount of ink passing through the ink filter is large, the ink filter is more likely to become clogged in a shorter period, and if the amount of ink passing through the ink filter is small, the ink filter is less likely to become clogged even if the inkjet printer is used for a long time.

[0005] Therefore, when the ink filter is replaced regularly, there is a risk that the ink filter will become clogged before the regular replacement and the above problems will occur. Also, when the ink filter is replaced regularly, there is a risk that an ink filter having a sufficient foreign matter removal function (i.e., an ink filter that is not clogged) will be replaced and discarded. Therefore, in an inkjet printer in which an ink filter is disposed in the ink supply path to the inkjet head, it is preferable that the state of the ink filter can be objectively grasped in order to appropriately determine the replacement timing of the ink filter.

[0006] Therefore, an object of the present invention is to provide an inkjet printer capable of objectively grasping the state of an ink filter in an inkjet printer including an ink filter disposed in an ink supply path to an inkjet head. Another object of the present invention is to provide a control method for an inkjet printer capable of objectively grasping the state of an ink filter in an inkjet printer including an ink filter disposed in an ink supply path to an inkjet head.

Means for Solving the Problems

[0007] To solve the above problems, an inkjet printer according to the present invention is an inkjet printer including an inkjet head that discharges ink, and includes a sub-tank that stores ink supplied to the inkjet head, a buffer tank that stores ink supplied to the sub-tank, a main tank that stores ink supplied to the buffer tank, a pump disposed in a piping path between the buffer tank and the sub-tank, a first piping path that is a piping path connecting the main tank and the buffer tank, a second piping path that is a piping path connecting the buffer tank and the pump, a third piping path that is a piping path connecting the pump and the sub-tank, a fourth piping path that is a piping path connecting the third piping path and the main tank, an ink filter disposed in a piping path between a connection point of the third piping path and the fourth piping path and the buffer tank, a first on-off valve disposed in a piping path between a connection point of the third piping path and the fourth piping path and the sub-tank, a second on-off valve disposed in the fourth piping path, a detection mechanism for detecting the amount of ink stored in the main tank, and a control unit for controlling the inkjet printer. The control unit drives the pump at a constant speed for a certain period of time with the first piping path closed, the first on-off valve closed, and the second on-off valve open, to flow ink from the buffer tank to the main tank, and calculates an increase amount of ink in the main tank after driving the pump from the amount of ink in the main tank before driving the pump based on the detection result of the detection mechanism, or drives the pump at a constant speed with the first piping path closed, the first on-off valve closed, and the second on-off valve open, to flow ink from the buffer tank to the main tank that stores a certain amount of ink, and calculates a time until the amount of ink in the main tank detected by the detection mechanism reaches a predetermined amount.

[0008] Also, to solve the above problems, a control method for an inkjet printer according to the present invention includes an inkjet head that discharges ink, a sub-tank that stores ink supplied to the inkjet head, a buffer tank that stores ink supplied to the sub-tank, a main tank that stores ink supplied to the buffer tank, a pump disposed in a piping path between the buffer tank and the sub-tank, a first piping path that is a piping path connecting the main tank and the buffer tank, a second piping path that is a piping path connecting the buffer tank and the pump, a third piping path that is a piping path connecting the pump and the sub-tank, a fourth piping path that is a piping path connecting the third piping path and the main tank, an ink filter disposed in a piping path between a connection point between the third piping path and the fourth piping path and the buffer tank, a first on-off valve disposed in a piping path between a connection point between the third piping path and the fourth piping path and the sub-tank, a second on-off valve disposed in the fourth piping path, and a detection mechanism for detecting the amount of ink in the main tank. The control method for the inkjet printer is characterized in that, with the first piping path closed and the first on-off valve closed and the second on-off valve open, the pump is driven at a constant speed for a certain period of time to flow ink from the buffer tank to the main tank, and based on the detection result of the detection mechanism, the increase amount of ink in the main tank after driving the pump is calculated from the amount of ink in the main tank before driving the pump, or, with the first piping path closed and the first on-off valve closed and the second on-off valve open, the pump is driven at a constant speed to flow ink from the buffer tank to the main tank that stores a certain amount of ink, and the time until the amount of ink in the main tank detected by the detection mechanism reaches a predetermined amount is calculated.

[0009] In the present invention, with the first piping path closed so that ink does not flow from the main tank to the buffer tank, the pump is driven at a constant speed for a certain period of time to flow ink from the buffer tank to the main tank, and based on the detection result of the detection mechanism, the increase amount of the ink in the main tank after driving the pump is calculated from the amount of the ink in the main tank before driving the pump. In the present invention, since the ink flowing from the buffer tank to the main tank passes through the ink filter, the increase amount of the ink in the main tank after driving the pump varies from the amount of the ink in the main tank before driving the pump depending on the state of the ink filter. Therefore, in the present invention, by calculating the increase amount of the ink, it becomes possible to objectively grasp the state of the ink filter disposed in the piping path between the buffer tank and the sub-tank. Further, in the present invention, since it becomes possible to objectively grasp the state of the ink filter, it becomes possible to objectively determine the replacement timing of the ink filter.

[0010] Alternatively, in the present invention, with the first piping path closed so that ink does not flow from the main tank to the buffer tank, the pump is driven at a constant speed to flow ink from the buffer tank to the main tank in which a certain amount of ink is stored, and the time until the amount of the ink in the main tank detected by the detection mechanism reaches a predetermined amount is calculated. In the present invention, since the ink flowing from the buffer tank to the main tank passes through the ink filter, the time until the amount of the ink in the main tank detected by the detection mechanism reaches a predetermined amount varies depending on the state of the ink filter. Therefore, in the present invention, by calculating the time until the amount of the ink in the main tank reaches a predetermined amount, it becomes possible to objectively grasp the state of the ink filter disposed in the piping path between the buffer tank and the sub-tank. Further, in the present invention, since it becomes possible to objectively grasp the state of the ink filter, it becomes possible to objectively determine the replacement timing of the ink filter.

[0011] In the present invention, for example, the control unit calculates the increase in the amount of ink in the main tank after driving the pump from the amount of ink in the main tank before driving the pump based on the detection result of the detection mechanism.

[0012] Also, in order to solve the above problems, an inkjet printer of the present invention is an inkjet printer including an inkjet head that discharges ink, and includes a sub-tank that stores ink supplied to the inkjet head, an ink filter disposed in a piping path between the sub-tank and the inkjet head, a pump for applying a positive pressure to the inside of the sub-tank, a detection mechanism for detecting the amount of ink stored in the sub-tank, and a control unit for controlling the inkjet printer. The control unit drives the pump to set a constant positive pressure in the sub-tank, flows ink from the sub-tank storing a certain amount of ink to the inkjet head, and calculates the time until the amount of ink in the sub-tank detected by the detection mechanism reaches a predetermined amount, or drives the pump to set a constant positive pressure in the sub-tank for a certain time and flows ink from the sub-tank to the inkjet head, and calculates the decrease in the amount of ink in the sub-tank after driving the pump from the amount of ink in the sub-tank before driving the pump based on the detection result of the detection mechanism.

[0013] Furthermore, to solve the above problems, a method for controlling an inkjet printer according to the present invention includes an inkjet head that discharges ink, a sub-tank that stores the ink supplied to the inkjet head, an ink filter disposed in a piping path between the sub-tank and the inkjet head, a pump for applying a positive pressure inside the sub-tank, and a detection mechanism for detecting the amount of ink stored in the sub-tank. The method for controlling the inkjet printer drives the pump to apply a constant positive pressure inside the sub-tank, flows ink from the sub-tank storing a certain amount of ink to the inkjet head, and calculates the time until the amount of ink in the sub-tank detected by the detection mechanism reaches a predetermined amount. Alternatively, the pump is driven to apply a constant positive pressure inside the sub-tank for a certain period of time, ink is flowed from the sub-tank to the inkjet head, and based on the detection result of the detection mechanism, the amount of ink reduction in the sub-tank after driving the pump is calculated from the amount of ink in the sub-tank before driving the pump.

[0014] In the present invention, the pump is driven to apply a constant positive pressure inside the sub-tank, ink is flowed from the sub-tank storing a certain amount of ink to the inkjet head, and the time until the amount of ink in the sub-tank detected by the detection mechanism reaches a predetermined amount is calculated. In the present invention, since the ink flowing from the sub-tank to the inkjet head passes through the ink filter, the time until the amount of ink in the sub-tank detected by the detection mechanism reaches a predetermined amount varies depending on the state of the ink filter. Therefore, in the present invention, by calculating the time until the amount of ink in the sub-tank reaches a predetermined amount, it becomes possible to objectively grasp the state of the ink filter disposed in the piping path between the sub-tank and the inkjet head. Further, in the present invention, since it becomes possible to objectively grasp the state of the ink filter, it becomes possible to objectively determine the replacement timing of the ink filter.

[0015] Alternatively, in the present invention, a pump is driven to maintain a constant positive pressure in the sub-tank for a certain period of time, causing ink to flow from the sub-tank to the inkjet head. Based on the detection result of the detection mechanism, the amount of ink reduction in the sub-tank after driving the pump is calculated from the amount of ink in the sub-tank before driving the pump. In the present invention, since the ink flowing from the sub-tank to the inkjet head passes through the ink filter, the amount of ink reduction in the sub-tank after driving the pump varies depending on the state of the ink filter from the amount of ink in the sub-tank before driving the pump. Therefore, in the present invention, by calculating the amount of ink reduction, it becomes possible to objectively grasp the state of the ink filter disposed in the piping path between the sub-tank and the inkjet head. Further, in the present invention, since it becomes possible to objectively grasp the state of the ink filter, it becomes possible to objectively determine the replacement timing of the ink filter.

[0016] In the present invention, for example, the detection mechanism is a liquid level detection mechanism for detecting the height of the ink liquid level in the sub-tank, and the control unit calculates the time until the amount of ink in the sub-tank detected by the detection mechanism reaches a predetermined amount. In this case, since it becomes possible to calculate the time until the amount of ink in the sub-tank reaches a predetermined amount by using a liquid level detection mechanism for detecting the height of the ink liquid level in the sub-tank, compared with the case where a detection mechanism is provided separately from the liquid level detection mechanism, it becomes possible to simplify the configuration of the inkjet printer.

Advantages of the Invention

[0017] As described above, in the present invention, in an inkjet printer including an ink filter disposed in the ink supply path to the inkjet head, it becomes possible to objectively grasp the state of the ink filter.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0020] (Configuration of Inkjet Printer) FIG. 1 is a schematic diagram for explaining the configuration of an inkjet printer 1 according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the configuration of the inkjet printer 1 shown in FIG. 1. FIG. 3 is a block diagram for explaining the configuration of the inkjet printer 1 shown in FIG. 1.

[0021] The inkjet printer 1 of this embodiment (hereinafter referred to as "printer 1") is, for example, an inkjet printer for business use and performs printing on a medium 2 such as paper. The printer 1 includes an inkjet head 3 (hereinafter referred to as "head 3") that discharges ink, a carriage 4 on which the head 3 is mounted, a carriage drive mechanism 5 that moves the carriage 4 in the main scanning direction, a guide rail 6 for guiding the carriage 4 in the main scanning direction, and a platen 7 on which the medium 2 is placed during printing. When printing on the medium 2 with the printer 1, the head 3 discharges ink while the carriage 4 reciprocates in the main scanning direction.

[0022] Further, the printer 1 includes a sub-tank 11 that stores ink supplied to the head 3, a buffer tank 12 that stores ink supplied to the sub-tank 11, and a main tank 13 that stores ink supplied to the buffer tank 12. In this embodiment, for example, one buffer tank 12 is connected to one main tank 13. Also, for example, two sub-tanks 11 are connected to one buffer tank 12, and ink is supplied from one buffer tank 12 to the two sub-tanks 11. Although one main tank 13 is illustrated in FIG. 2, the printer 1 includes a plurality of main tanks 13. The printer 1 includes a plurality of buffer tanks 12 and sub-tanks 11 corresponding to the number of main tanks 13.

[0023] Furthermore, the printer 1 includes a pump (liquid feeding pump) 14 and an ink filter 15 (hereinafter referred to as "filter 15") disposed in the piping path between the buffer tank 12 and the sub-tank 11, a detection mechanism 16 for detecting the amount of ink stored in the main tank 13, and a control unit 17 for controlling the printer 1. The printer 1 also includes a first piping path 19 that is a piping path connecting the main tank 13 and the buffer tank 12, a second piping path 20 that is a piping path connecting the buffer tank 12 and the pump 14, a third piping path 21 that is a piping path connecting the pump 14 and the two sub-tanks 11, and a fourth piping path 22 that is a piping path connecting the third piping path 21 and the main tank 13.

[0024] In addition, the printer 1 includes a shut-off valve 23 disposed in the first piping path 19, a shut-off valve 24 as the first shut-off valve disposed in the third piping path 21, a shut-off valve 25 as the second shut-off valve disposed in the fourth piping path 22, an ink filter 27 (hereinafter referred to as "filter 27") disposed in the piping path between the sub-tank 11 and the head 3, a deaeration module 28 for removing gas in the ink, a pressure adjustment mechanism 29 for adjusting the pressure in the sub-tank 11, a shut-off valve 30 disposed in the piping path between the pressure adjustment mechanism 29 and the sub-tank 11, and a detection mechanism 31 for detecting the amount of ink stored in the sub-tank 11.

[0025] The two sub-tanks 11 connected to one buffer tank 12 are connected in parallel to the pump 14 via the third piping path 21. The third piping path 21 branches on the sub-tank 11 side from the connection point (connection location) between the third piping path 21 and the fourth piping path 22. The shut-off valve 24 is disposed in the piping path between the branch point of the third piping path 21 and the sub-tank 11, and two shut-off valves 24 are disposed in the third piping path 21. That is, the shut-off valve 24 is disposed in the piping path between the connection location between the third piping path 21 and the fourth piping path 22 and the sub-tank 11. The filter 15 is disposed in the second piping path 20. That is, the filter 15 is disposed in the piping path between the connection location between the third piping path 21 and the fourth piping path 22 and the buffer tank 12. The deaeration module 28 is disposed in the piping path between the sub-tank 11 and the filter 27.

[0026] The sub-tank 11 is mounted on the carriage 4. The main tank 13 is, for example, a hard ink bottle formed of resin. The capacity of the main tank 13 is, for example, 10 liters. The buffer tank 12 is an ink pack formed in a bag shape. The buffer tank 12 includes a bag-shaped tank body constituted by a flexible film, and an ink inlet and an outlet attached to the tank body. The buffer tank 12 is, for example, an aluminum pack having an aluminum tank body. The capacity of the buffer tank 12 is, for example, 2 liters. Ink is supplied from the main tank 13 to the buffer tank 12 by a head difference. That is, ink is supplied from the main tank 13 to the buffer tank 12 by utilizing the difference in the height of the ink liquid level in the main tank 13 and the height of the ink liquid level in the buffer tank 12.

[0027] The pump 14 serves functions such as sending ink from the buffer tank 12 to the sub-tank 11. The pump 14 is electrically connected to the control unit 17. The on-off valves 23 to 25, 30 are solenoid valves. The on-off valves 23 to 25, 30 are electrically connected to the control unit 17. The detection mechanism 16 is a load cell for detecting the weight of the ink accommodated in the main tank 13. The detection mechanism 16 includes a sensor 33. The sensor 33 is a strain gauge and is electrically connected to the control unit 17. The control unit 17 detects the weight of the ink accommodated in the main tank 13 based on the detection result of the detection mechanism 16 (specifically, the detection result of the sensor 33).

[0028] The detection mechanism 31 is a liquid level detection mechanism for detecting the height of the ink liquid level in the sub-tank 11. The detection mechanism 31 includes, for example, a float 34 floating on the ink in the sub-tank 11, a permanent magnet (not shown) built into the float 34, and three sensors 35 to 37 arranged outside the sub-tank 11 for detecting the permanent magnet. The sensors 35 to 37 are magnetic sensors such as Hall ICs. The sensor 35 is fixed to the outer surface of the sub-tank 11 on the upper end side of the sub-tank 11. The sensor 36 is fixed to the outer surface of the sub-tank 11 below the sensor 35. The sensor 37 is fixed to the outer surface of the sub-tank 11 on the lower end side of the sub-tank 11.

[0029] The sensor 35 is a sensor for detecting that the height of the ink liquid level in the sub-tank 11 is higher than a predetermined upper limit position. The sensor 36 is a sensor for detecting that the height of the ink liquid level in the sub-tank 11 is within an appropriate range. The sensor 37 is a sensor for detecting that the height of the ink liquid level in the sub-tank 11 is lower than a predetermined lower limit position. The sensors 35 to 37 are electrically connected to the control unit 17. The control unit 17 detects the height of the ink liquid level in the sub-tank 11 based on the detection results of the detection mechanism 31 (specifically, the detection results of the sensors 35 to 37), thereby detecting the amount (capacity) of the ink stored in the sub-tank 11.

[0030] The pressure adjustment mechanism 29 includes two pumps 39, 40, an air chamber 41 disposed in the piping path between the on-off valve 30 and the pumps 39, 40, and a three-way valve 42 disposed in the piping path between the pumps 39, 40 and the air chamber 41. The pump 39 is a positive pressure (positive pressure) pump for making the inside of the sub-tank 11 a positive pressure. The pump 40 is a negative pressure (negative pressure) pump for making the inside of the sub-tank 11 a negative pressure. The three-way valve 42 functions to switch the air flow path between the pumps 39, 40 and the sub-tank 11 between an air flow path connecting the pump 39 and the sub-tank 11 via the air chamber 41 and an air flow path connecting the pump 40 and the sub-tank 11 via the air chamber 41. The three-way valve 42 is a solenoid valve. The pumps 39, 40 and the three-way valve 42 are electrically connected to the control unit 17.

[0031] (Control Method of Inkjet Printer) During printing of the medium 2, the control unit 17 drives the pump 14 with the on-off valves 23, 24 opened and the on-off valve 25 closed based on the detection result of the detection mechanism 31 to supply ink from the buffer tank 12 to the sub-tank 11. During printing of the medium 2, for example, an air flow path connecting the pump 40 and the sub-tank 11 is formed and the on-off valve 30 is open, and the inside of the sub-tank 11 is at a negative pressure. During printing of the medium 2, ink is supplied from the buffer tank 12 to the sub-tank 11. Therefore, even when the ink in the main tank 13 runs out during printing of the medium 2 and the replacement work of the main tank 13 is being carried out, ink is supplied from the buffer tank 12 to the sub-tank 11. Note that the replacement work of the main tank 13 during printing of the medium 2 is carried out after closing the on-off valve 23, and when the replacement work of the main tank 13 is completed, the on-off valve 23 is opened.

[0032] Also, in the printer 1, in order to suppress sedimentation of ink particles in the main tank 13 and the buffer tank 12, ink is circulated during a pause in which printing of the medium 2 is not performed and the carriage 4 has stopped for a predetermined time or longer. Specifically, the control unit 17 closes the on-off valve 24 and opens the on-off valves 23 and 25 to form a circulation path for the ink passing through the main tank 13 and the buffer tank 12, and then drives the pump 14 to circulate the ink in this circulation path.

[0033] In this embodiment, when the printer 1 is maintained, the state of the filter 15 is checked. The check of the state of the filter 15 is started when a predetermined operation is performed on an operation screen for an operator who performs maintenance to operate the printer 1. In the check of the state of the filter 15, the control unit 17 closes the on-off valves 23 and 24 and opens the on-off valve 25 (that is, with the first piping path 19 closed, the on-off valve 24 closed, and the on-off valve 25 open), and drives the pump 14 at a constant speed for a certain time to flow the ink from the buffer tank 12 to the main tank 13. For example, the control unit 17 drives the pump 14 for one minute to flow the ink from the buffer tank 12 to the main tank 13.

[0034] Also, the control unit 17 calculates an increase amount of the ink in the main tank 13 after driving the pump 14 for one minute from the amount of the ink in the main tank 13 before driving the pump 14, based on the detection result of the detection mechanism 16. Specifically, the control unit 17 calculates an increased weight of the ink in the main tank 13 after driving the pump 14 for one minute from the weight of the ink in the main tank 13 before driving the pump 14. The control unit 17 displays the calculated increase amount (increased weight) of the ink on a predetermined display unit 45 such as a display.

[0035] Since the ink flowing from the buffer tank 12 to the main tank 13 passes through the filter 15, the increase in the amount of ink in the main tank 13 after driving the pump 14 varies from the amount of ink in the main tank 13 before driving the pump 14 depending on the state of the filter 15 (specifically, depending on the degree of clogging of the filter 15). Therefore, the operator can quantitatively grasp the state of the filter 15 (the degree of clogging of the filter 15) by checking the increase in the amount of ink displayed on the display unit 45. That is, the operator can objectively grasp the state of the filter 15 by checking the increase in the amount of ink displayed on the display unit 45.

[0036] Also, in this embodiment, the state of the filter 27 is checked during maintenance. The check of the state of the filter 27 is started when the operator performs a predetermined operation on the operation screen. At the start of the check of the state of the filter 27, the amount of ink stored in the sub-tank 11 is a certain amount. In the check of the state of the filter 27, the control unit 17 drives the pump 39 with the on-off valve 24 closed and the on-off valve 30 open after switching the three-way valve 42 so as to form an air flow path connecting the pump 39 and the sub-tank 11, and makes the inside of the sub-tank 11 at a certain positive pressure, and causes the ink to flow from the sub-tank 11 containing a certain amount of ink to the head 3. The ink that has flowed from the sub-tank 11 to the head 3 flows out from the nozzles of the head 3.

[0037] Also, the control unit 17 calculates the time until the amount of ink in the sub-tank 11 detected by the detection mechanism 31 reaches a predetermined amount. Specifically, the control unit 17 calculates the time until the height of the ink liquid level in the sub-tank 11 is detected by the sensor 37 (specifically, the time until the permanent magnet built into the float 34 is detected by the sensor 37). That is, the control unit 17 calculates the time until the height of the ink liquid level in the sub-tank 11 becomes lower than a predetermined lower limit position. The control unit 17 displays the calculated time on the display unit 45.

[0038] Since the ink flowing from the sub-tank 11 to the head 3 passes through the filter 27, the time until the amount of ink in the sub-tank 11 detected by the detection mechanism 31 reaches a predetermined amount varies depending on the state of the filter 27 (specifically, the degree of clogging of the filter 27). Therefore, the operator can quantitatively grasp the state of the filter 27 (the degree of clogging of the filter 27) by checking the time displayed on the display unit 45. That is, the operator can objectively grasp the state of the filter 27 by checking the time displayed on the display unit 45.

[0039] (Main effects of this embodiment) As described above, in this embodiment, the control unit 17 drives the pump 14 at a constant speed for a certain time with the on-off valves 23 and 24 closed and the on-off valve 25 open, to flow the ink from the buffer tank 12 to the main tank 13, and calculates the increase amount of the ink in the main tank 13 after driving the pump 14 from the amount of ink in the main tank 13 before driving the pump 14 based on the detection result of the detection mechanism 16. Also, in this embodiment, the control unit 17 displays the calculated increase amount of the ink on the display unit 45. Therefore, in this embodiment, as described above, it becomes possible to objectively grasp the state of the filter 15. Also, in this embodiment, since it becomes possible to objectively grasp the state of the filter 15, it becomes possible to objectively determine the replacement timing of the filter 15.

[0040] In this embodiment, the control unit 17 drives the pump 39 with the on-off valve 24 closed and the on-off valve 30 open to set a constant positive pressure in the sub-tank 11, and flows the ink from the sub-tank 11 in which a certain amount of ink is stored to the head 3, and calculates the time until the amount of ink in the sub-tank 11 detected by the detection mechanism 31 reaches a predetermined amount. Also, the control unit 17 displays the calculated time on the display unit 45. Therefore, in this embodiment, as described above, it becomes possible to objectively grasp the state of the filter 27. Also, in this embodiment, since it becomes possible to objectively grasp the state of the filter 27, it becomes possible to objectively determine the replacement timing of the filter 27.

[0041] In this embodiment, the detection mechanism 31 is a liquid level detection mechanism for detecting the height of the ink liquid level in the sub-tank 11. When checking the state of the filter 27, the detection mechanism 31, which is a liquid level detection mechanism, is used to calculate the time until the amount of ink in the sub-tank 11 reaches a predetermined amount. Therefore, in this embodiment, compared with the case where a detection mechanism 31 for detecting the amount of ink stored in the sub-tank 11 is provided separately from the liquid level detection mechanism, the configuration of the printer 1 can be simplified.

[0042] (Other embodiments) The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

[0043] In the above-described embodiment, when the increase amount of ink calculated when the control unit 17 checks the state of the filter 15 is less than a predetermined reference amount, the control unit 17 may display a predetermined display indicating that it is time to replace the filter 15 on the display unit 45. Further, in the above-described embodiment, when the time calculated when the control unit 17 checks the state of the filter 27 exceeds a predetermined reference time, the control unit 17 may display a predetermined display indicating that it is time to replace the filter 27 on the display unit 45.

[0044] In the above-described embodiment, the state check of the filter 15 may be performed as follows. That is, after setting a certain amount of the ink stored in the main tank 13, the control unit 17 closes the on-off valves 23 and 24 and drives the pump 14 at a constant speed with the on-off valve 25 open, causing ink to flow from the buffer tank 12 into the main tank 13 where a certain amount of ink is stored, and calculating the time until the amount of ink in the main tank 13 detected by the detection mechanism 16 reaches a predetermined amount. In this case, the control unit 17 may display, for example, the calculated time on the display unit 45.

[0045] Since the ink flowing from the buffer tank 12 to the main tank 13 passes through the filter 15, depending on the state of the filter 15 (the degree of clogging of the filter 15), the time until the amount of ink in the main tank 13 detected by the detection mechanism 16 reaches a predetermined amount varies. Therefore, even in this case, by checking the time displayed on the display unit 45, it becomes possible to objectively grasp the state of the filter 15 (the degree of clogging of the filter 15).

[0046] In the above-described form, when the printer 1 is provided with a detection mechanism capable of continuously detecting the amount of ink stored in the sub-tank 11, the state of the filter 27 may be confirmed as follows. That is, the control unit 17 drives the pump 39 to set a constant positive pressure in the sub-tank 11 for a certain period of time to flow the ink from the sub-tank 11 to the head 3, and calculates the decrease in the amount of ink in the sub-tank 11 after driving the pump 39 from the amount of ink in the sub-tank 11 before driving the pump 39 based on the detection result of the detection mechanism. In this case, the control unit 17 may display, for example, the calculated decrease in the amount of ink on the display unit 45.

[0047] Since the ink flowing from the sub-tank 11 to the head 3 passes through the filter 27, depending on the state of the filter 27 (the degree of clogging of the filter 27), the decrease in the amount of ink in the sub-tank 11 after driving the pump 39 from the amount of ink in the sub-tank 11 before driving the pump 39 varies. Therefore, even in this case, by checking the decrease in the amount of ink displayed on the display unit 45, it becomes possible to objectively grasp the state of the filter 27 (the degree of clogging of the filter 27).

[0048] In the above-described form, the three-way valve 42 may be a manual valve whose opening and closing operation is manually performed. Also, in the above-described form, at least one of the on-off valves 23 to 25 and 30 may be a manual valve whose opening and closing operation is manually performed. Further, in the above-described form, the detection mechanism 16 may be a detection mechanism other than a load cell, and the detection mechanism 31 may be a detection mechanism other than a liquid level detection mechanism.

[0049] In the above-described embodiment, the buffer tank 12 does not have to be an ink pack. For example, the buffer tank 12 may be a hard ink tank having a liquid level detection function. In this case, the control unit 17 controls the valve 23 and the pump 14 while monitoring the amount of ink in the buffer tank 12. Also, in this case, the control unit 17 calculates the amount of ink reduction in the buffer tank 12 after driving the pump 14 from the amount of ink in the buffer tank 12 before driving the pump 14. Even in this case, it is possible to objectively grasp the state of the filter 15.

[0050] In the above-described embodiment, the printer 1 may include a pump disposed in the first piping path 19. In this case, ink is supplied from the main tank 13 to the buffer tank 12 by this pump. Also, in this case, the printer 1 does not have to include the on-off valve 23. When the printer 1 does not include the on-off valve 23, when checking the state of the filter 15, the control unit 17 closes the first piping path 19 by stopping the pump disposed in the first piping path 19.

[0051] In the above-described embodiment, the filter 15 may be disposed in the piping path between the connection point of the third piping path 21 and the fourth piping path 22 and the pump 14. That is, the filter 15 may be disposed on the discharge side of the pump 14. Even in this case, the filter 15 is disposed in the piping path between the connection point of the third piping path 21 and the fourth piping path 22 and the buffer tank 12. Also, in the above-described embodiment, the printer 1 is a device for printing on the medium 2, but the printer 1 may be used for purposes other than printing on the medium 2. For example, the printer 1 may be a 3D printer for forming a three-dimensional object. Also, the printer 1 may be an inkjet printer for general consumers.

Description of Reference Numerals

[0052] 1 Printer (Inkjet Printer) 3 Heads (Inkjet Head) 11 Sub - tank 12 Buffer Tank 13 Main Tank 14 Pump 15 Filter (Ink Filter) 16 Detection Mechanism 17 Control Unit 19 First Pipeline Route 20 Second Pipeline Route 21 Third Pipeline Route 22 Fourth Pipeline Route 24 On - Off Valve (First On - Off Valve) 25 On - Off Valve (Second On - Off Valve) 27 Filter (Ink Filter) 31 Detection Mechanism 39 Pump

Claims

1. In an inkjet printer including an inkjet head that discharges ink, a sub-tank that stores ink supplied to the inkjet head, a buffer tank that stores ink supplied to the sub-tank, a main tank that stores ink supplied to the buffer tank, a pump disposed in a piping path between the buffer tank and the sub-tank, a first piping path that is a piping path connecting the main tank and the buffer tank, a second piping path that is a piping path connecting the buffer tank and the pump, a third piping path that is a piping path connecting the pump and the sub-tank, a fourth piping path that is a piping path connecting the third piping path and the main tank, an ink filter disposed in a piping path between a connection point of the third piping path and the fourth piping path and the buffer tank, a first on-off valve disposed in a piping path between a connection point of the third piping path and the fourth piping path and the sub-tank, a second on-off valve disposed in the fourth piping path, a detection mechanism for detecting the amount of ink stored in the main tank, and a control unit for controlling the inkjet printer, the control unit, while closing the first piping path and closing the first on-off valve and opening the second on-off valve, drives the pump at a constant speed for a certain period of time to flow ink from the buffer tank to the main tank, and calculates an increase amount of ink in the main tank after driving the pump from the amount of ink in the main tank before driving the pump based on a detection result of the detection mechanism, or while closing the first piping path and closing the first on-off valve and opening the second on-off valve, drives the pump at a constant speed to flow ink from the buffer tank to the main tank that stores a certain amount of ink, and calculates a time until the amount of ink in the main tank detected by the detection mechanism reaches a predetermined amount. An inkjet printer characterized by this.

2. The control unit calculates an increase amount of ink in the main tank after driving the pump from the amount of ink in the main tank before driving the pump based on a detection result of the detection mechanism. The inkjet printer according to Claim 1, characterized by this.

3. In an inkjet printer having an inkjet head for ejecting ink, a sub-tank for storing the ink supplied to the inkjet head, an ink filter disposed in a piping path between the sub-tank and the inkjet head, a pump for applying a positive pressure to the inside of the sub-tank, a detection mechanism for detecting the amount of ink stored in the sub-tank, and a control unit for controlling the inkjet printer, the control unit, drives the pump to apply a constant positive pressure to the inside of the sub-tank, allows ink to flow from the sub-tank storing a certain amount of ink to the inkjet head, and calculates the time until the amount of ink in the sub-tank detected by the detection mechanism reaches a predetermined amount, or drives the pump to apply a constant positive pressure to the inside of the sub-tank for a certain time, allows ink to flow from the sub-tank to the inkjet head, and calculates the amount of decrease in the ink in the sub-tank after driving the pump from the amount of ink in the sub-tank before driving the pump based on the detection result of the detection mechanism. An inkjet printer characterized by this.

4. The detection mechanism is a liquid level detection mechanism for detecting the height of the ink liquid level in the sub-tank, The control unit calculates the time until the amount of ink in the sub-tank detected by the detection mechanism reaches a predetermined amount. The inkjet printer according to claim 3, characterized by this.

5. An inkjet head that discharges ink, a sub-tank that stores ink supplied to the inkjet head, a buffer tank that stores ink supplied to the sub-tank, a main tank that stores ink supplied to the buffer tank, a pump disposed in a piping path between the buffer tank and the sub-tank, a first piping path that is a piping path connecting the main tank and the buffer tank, a second piping path that is a piping path connecting the buffer tank and the pump, a third piping path that is a piping path connecting the pump and the sub-tank, a fourth piping path that is a piping path connecting the third piping path and the main tank, an ink filter disposed in a piping path between a connection point of the third piping path and the fourth piping path and the buffer tank, a first on-off valve disposed in a piping path between a connection point of the third piping path and the fourth piping path and the sub-tank, a second on-off valve disposed in the fourth piping path, and a detection mechanism for detecting the amount of ink in the main tank, and a control method for an inkjet printer comprising: With the first piping path closed and the first on-off valve closed and the second on-off valve open, the pump is driven at a constant speed for a certain period of time to flow ink from the buffer tank to the main tank, and based on the detection result of the detection mechanism, calculate the increase in the amount of ink in the main tank after driving the pump from the amount of ink in the main tank before driving the pump, or With the first piping path closed and the first on-off valve closed and the second on-off valve open, the pump is driven at a constant speed to flow ink from the buffer tank to the main tank that stores a certain amount of ink, and calculate the time until the amount of ink in the main tank detected by the detection mechanism reaches a predetermined amount. A control method for an inkjet printer characterized by this.

6. An inkjet printer control method comprising an inkjet head that discharges ink, a sub-tank that stores the ink supplied to the inkjet head, an ink filter disposed in a piping path between the sub-tank and the inkjet head, a pump for applying a positive pressure inside the sub-tank, and a detection mechanism for detecting the amount of ink stored in the sub-tank, driving the pump to apply a constant positive pressure inside the sub-tank, flowing ink from the sub-tank storing a certain amount of ink to the inkjet head, and calculating the time until the amount of ink in the sub-tank detected by the detection mechanism reaches a predetermined amount, or driving the pump to apply a constant positive pressure inside the sub-tank for a certain time, flowing ink from the sub-tank to the inkjet head, and calculating the decrease in the amount of ink in the sub-tank after driving the pump from the amount of ink in the sub-tank before driving the pump based on the detection result of the detection mechanism. A control method for an inkjet printer characterized by this.

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