Inkjet printing equipment

Abstract

In an inkjet printing device, the user can easily recognize the difference in water head between the ink tank and the inkjet head. [Solution] The inkjet printing apparatus 1 comprises a main unit 10 having an ink tank (pressure tank 11 and negative pressure tank 12) for storing ink (IK), a head unit 20 having an inkjet head 21 for ejecting ink (IK) supplied from the ink tanks (11, 12), and a liquid pipe 30 connected to the main unit 10 and the head unit 20, into which liquid W representing the head difference between the ink tank (pressure tank 11 and negative pressure tank 12) and the inkjet head 21 is injected.

Description

Technical Field

[0001] The present invention relates to an inkjet printing apparatus including an inkjet head and an ink tank.

Background Art

[0002] Conventionally, in an inkjet printing apparatus, in the standby state of the inkjet head, the nozzle pressure of the inkjet head is maintained at a slightly negative pressure by opening the ink tank (a pressurized tank located upstream of the inkjet head and a negative pressure tank located downstream of the inkjet head).

[0003] Although it is for checking the remaining ink amount from outside the apparatus, a recording apparatus has been proposed that includes a remaining amount confirmation portion formed of a material having a transparency that allows the liquid remaining amount in the ink tank to be visually recognized (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in an inkjet head printing apparatus in which the ink tank and the inkjet head are arranged in the same housing, the head difference between the ink tank and the inkjet head does not change. On the other hand, in an inkjet head printing apparatus in which the ink tank and the inkjet head are arranged in separate housings, there is a risk of unintentionally changing the head difference during manufacturing, transportation, user operation (including maintenance), etc.

[0006] If the head difference described above changes to an inappropriate value, it can cause ink leaks and color mixing, stain the floor where the inkjet printer is installed and the user with ink, and result in significant loss costs and recovery time due to the replacement and cleaning of internal parts of the inkjet printer. Users need to recognize abnormalities in the head difference as quickly as possible, but this has not been easy to do in the past.

[0007] The objective of the present invention is to provide an inkjet printing apparatus that allows the user to easily recognize the difference in water head between the ink tank and the inkjet head. [Means for solving the problem]

[0008] In one embodiment, the inkjet printing apparatus comprises a main unit having an ink tank for storing ink, a head unit having an inkjet head for discharging the ink supplied from the ink tank, and a liquid pipe connected to the main unit and the head unit, into which a liquid representing the head difference between the ink tank and the inkjet head is injected. [Effects of the Invention]

[0009] According to the above embodiment, the user can easily recognize the difference in water head between the ink tank and the inkjet head. [Brief explanation of the drawing]

[0010] [Figure 1] This is a configuration diagram showing an inkjet printing apparatus according to one embodiment. [Figure 2] This is a diagram showing the main unit and inkjet head in one embodiment. [Figure 3] This is a block diagram showing the control configuration of an inkjet printing apparatus according to one embodiment. [Figure 4] This is a diagram showing the configuration of an inkjet printing apparatus after the head unit has been rotated in one embodiment. [Figure 5]This is a diagram showing a water pipe holding mechanism in one embodiment. [Figure 6] This is a diagram showing the configuration of an inkjet printing apparatus after the head unit has been lowered in one embodiment. [Figure 7] This is a diagram illustrating the main unit and inkjet head for explaining a water stop valve in one embodiment. [Figure 8] This is a configuration diagram showing an inkjet printing apparatus according to a modified embodiment. [Figure 9] This is a configuration diagram showing an inkjet printing apparatus after head unit rotation in a modified example of one embodiment. [Figure 10] This is a configuration diagram showing the main unit for illustrating a modified version of one embodiment of the float. [Modes for carrying out the invention]

[0011] Hereinafter, an inkjet printing apparatus according to one embodiment of the present invention will be described with reference to the drawings.

[0012] Figure 1 is a configuration diagram showing an inkjet printing apparatus 1 according to one embodiment.

[0013] Figure 2 is a configuration diagram showing the main unit 10 and the inkjet head 21.

[0014] Figure 3 is a block diagram showing the control configuration of the inkjet printing apparatus 1.

[0015] As shown in FIG. 1, the inkjet printing apparatus 1 includes a main body unit 10, a head unit 20, a liquid pipe 30, a status display unit 40, and liquid level sensors S1 to S4 (first liquid level sensor S1, second liquid level sensor S2, third liquid level sensor S3, and fourth liquid level sensor S4). Further, as shown in FIG. 3, the inkjet printing apparatus 1 includes a control unit 51, a storage unit 52, a display unit 53, an input unit 54, an interface unit 55, and an audio output unit 60. Further, as shown in FIG. 5, the inkjet printing apparatus 1 includes a water pipe holding mechanism 70.

[0016] As shown in FIG. 2, the main body unit 10 has a pressure tank 11, a negative pressure tank 12, ink circulation paths 13 to 15, and an ink pump P, and supplies ink IK to the inkjet head 21.

[0017] The pressure tank 11 and the negative pressure tank 12 are examples of ink tanks for storing ink IK. The pressure tank 11, the negative pressure tank 12, the ink circulation paths 13 to 15, and the ink pump P are connected to the inkjet head 21 to form a circulation flow path for circulating ink IK and supplying ink IK to the inkjet head 21. This circulation flow path is arranged for each color of ink IK ejected by at least the inkjet head 21.

[0018] The pressure tank 11 stores ink IK supplied to the inkjet head 21. The pressure tank 11 is arranged at a position lower than the inkjet head 21. A pressure ink sensor S11 for detecting the liquid level of ink IK is arranged in the pressure tank 11. The ink IK in the pressure tank 11 is supplied to the inkjet head 21 via the ink circulation path 13. The ink IK supplied to the inkjet head 21 may be temperature-adjusted by, for example, a heat sink, a cooling fan, a heater, etc. As will be described later, since the inkjet head 21, the pressure tank 11, and the negative pressure tank 12 are arranged with variable relative heights, the ink circulation path 13 is preferably a flexible hose. Note that an air layer is formed on the liquid surface of the ink IK in the pressure tank 11, and the pressure of the air layer is adjusted by a pressure adjustment mechanism not shown.

[0019] The negative pressure tank 12 stores the ink IK that has not been consumed by the inkjet head 21. The negative pressure tank 12 is arranged at the same height as the pressure tank 11. Inside the negative pressure tank 12, a negative pressure ink sensor S12 for detecting the liquid level of the ink IK is arranged. The negative pressure tank 12 receives the ink IK from the inkjet head 21 via the ink circulation path 14. The ink circulation path 14 may be a flexible hose similar to the ink circulation path 13. Also, the negative pressure tank 12 receives the ink IK from an ink supply source such as an ink cartridge. Note that an air layer is formed on the liquid surface of the ink IK inside the negative pressure tank 12, and the pressure of the air layer is adjusted by a pressure adjustment mechanism (not shown).

[0020] The ink pump P supplies the ink IK from the negative pressure tank 12 to the pressure tank 11 via the ink circulation path 15.

[0021] Here, while the pressure tank 11 and the negative pressure tank 12 are arranged in the main body unit 10, the inkjet head 21 is arranged in the head unit 20 of a separate housing from the main body unit 10. Therefore, by relatively moving the main body unit 10 and the head unit 20 in the height direction, the relative height between the pressure tank 11 and the negative pressure tank 12 and the inkjet head 21 changes. Accordingly, the head difference (the difference between the lower end (spray surface) of the inkjet head 21 shown in FIG. 2 and the liquid surface height of the pressure tank 11 and the negative pressure tank 12) between the pressure tank 11 and the negative pressure tank 12 and the inkjet head 21 changes.

[0022] The head unit 20 shown in Figure 1 has an inkjet head 21 that ejects ink IK supplied from the pressurized tank 11. In the state shown in Figure 2, the inkjet head 21 ejects ink IK downwards. Note that in Figure 1, the inkjet head 21, pressurized tank 11, and negative pressure tank 12 are positioned so that they are not visible, and are therefore shown with dashed lines (hidden lines). Also, in Figure 1, the pressurized tank 11 and the negative pressure tank 12 are shown as being in overlapping positions.

[0023] The liquid tube 30 has a vertical portion 31 on the main body side, a vertical portion 32 on the head side, and a connecting portion 33, into which a liquid W, such as water, is injected.

[0024] The liquid pipe 30 is, for example, a flexible hose with open ends. The liquid pipe 30 is connected to the main unit 10 so as to be vertical in the main body side vertical portion 31, and connected to the head unit 20 so as to be vertical in the head side vertical portion 32. The connecting portion 33 is integrally provided on the main body side vertical portion 31 and the head side vertical portion 32, and connects the main body side vertical portion 31 and the head side vertical portion 32. The liquid W is injected into the liquid pipe 30 in an amount that spans the connecting portion 33, a part of the main body side vertical portion 31, and a part of the head side vertical portion 32. Note that because the main unit 10 and the head unit 20 move (or rotate) relative to each other, the connecting portion 33 does not maintain the horizontal state shown in Figure 1, but curves as appropriate.

[0025] The liquid tube 30 is preferably positioned so that the liquid level of at least one of the liquids W, either on the main unit 10 side or the head unit 20 side, is visible to the user. For example, the liquid tube 30 may be connected to the outer surfaces of the main unit 10 and the head unit 20 so that the entire liquid tube 30 is visible, or the liquid tube 30 may be connected to the inside of the main unit 10 and the head unit 20, and openings or transparent windows may be provided in the housings of the main unit 10 and the head unit 20 to allow the liquid level of the liquid W to be visible.

[0026] The pressurized tank 11 and the negative pressure tank 12 move together with the main unit 10, and the inkjet head 21 moves together with the head unit 20. In addition, the liquid level at both open ends of the liquid tube 30 remains at the same height regardless of the movement state. Therefore, the liquid W (liquid level) injected into the liquid tube 30 represents the head difference between the pressurized tank 11 and the negative pressure tank 12 and the inkjet head 21, and when the head difference changes due to the movement of the main unit 10 or the head unit 20, the liquid level on the right side of the liquid tube 30 changes. The present invention utilizes the above principle.

[0027] The status indicator unit 40 displays the head difference corresponding to the liquid level height of the liquid W in the liquid tube 30, and is provided so that it can be visually confirmed by the user along with the liquid level height of the liquid W in the liquid tube 30. In the example shown in Figure 1, the status indicator unit 40 is provided on the head unit 20 side of the liquid tube 30, on the outer surface of the housing of the head unit 20 or on the outer surface of the liquid tube 30 (head-side vertical portion 32).

[0028] The status indicator section 40 displays, for example, the upper and lower limits of the ○ zone 41 where the liquid level is within an acceptable range for the predetermined head difference, the upper or lower limits of the two upper and lower △ zones 42 where the liquid level is between an acceptable and unacceptable range for the head difference, and the upper and lower limits of the two upper and lower × zones 43 where the liquid level is within an unacceptable range for the predetermined head difference. The status indicator section 40 is provided by attaching stickers or fixing components with printed lines and colored parts, such as lines and letters / symbols representing the upper or lower limits, and colored parts representing each zone 41 to 43, which are attached to the head unit 20 or liquid pipe 30. Note that in Figure 1, the lower limit of the lower × zone 43 is shown, but all areas below the lower △ zone 42 can be considered as the lower × zone 43.

[0029] The first liquid level sensor S1, the second liquid level sensor S2, the third liquid level sensor S3, and the fourth liquid level sensor S4 are examples of liquid level sensors that detect the liquid level height of liquid W in the liquid pipe 30, and any detection method such as capacitance can be used. The first liquid level sensor S1 detects the liquid level height at the boundary between the upper × zone 43 and the △ zone 42. The second liquid level sensor S2 detects the liquid level height at the boundary between the upper △ zone 42 and the ○ zone 41. The third liquid level sensor S3 detects the liquid level height at the boundary between the ○ zone 41 and the lower △ zone 42. The fourth liquid level sensor S4 detects the liquid level height at the boundary between the lower △ zone 42 and the lower × zone 43.

[0030] Therefore, if all three liquid level sensors S1, S2, S3, and S4 detect liquid W, it can be determined that the liquid level is in the upper X zone 43. Also, if only the second liquid level sensor S2, S3, and S4 detect liquid W, it can be determined that the liquid level is in the upper △ zone 42. Also, if only the third liquid level sensor S3 and S4 detect liquid W, it can be determined that the liquid level is in the ○ zone 41. Also, if only the fourth liquid level sensor S4 detects liquid W, it can be determined that the liquid level is in the lower △ zone 42. Furthermore, if none of the liquid level sensors S1 to S4 detect liquid W, it can be determined that the liquid level is in the lower X zone 43.

[0031] The control unit 51 shown in Figure 3 has a processor (e.g., CPU: Central Processing Unit) that functions as an arithmetic processing unit that controls the operation of the inkjet printing device 1, and controls the operation of each part of the inkjet printing device 1. For example, the control unit 51 controls the voice output unit 60 to notify the user of the head difference status corresponding to the liquid level height detected by the liquid level sensors S1 to S4.

[0032] The memory unit 52 may include, for example, a ROM (Read Only Memory), which is a read-only semiconductor memory in which a predetermined control program is pre-recorded, or a RAM (Random Access Memory), which is a semiconductor memory that can be written to and read at any time and used as a working memory area as needed when the processor executes various control programs, or a hard disk drive.

[0033] The display unit 53 includes a display, lamps, etc., that show various types of information.

[0034] The input unit 54 is an operation key, touch panel, or the like that accepts user input information. A single operation panel may function as both the display unit 53 and the input unit 54.

[0035] The interface unit 55 exchanges various types of information with external devices.

[0036] The audio output unit 60 outputs sound. The audio output unit 60 is an example of a notification unit that provides information to the user. The display unit 53 described above can provide information to the user through displays such as displays and lamps, so the display unit 53 may function as a notification unit in place of or together with the audio output unit 60.

[0037] Here, as shown in Figure 4, the inkjet head 21 (head unit 20) may be rotated 90 degrees during maintenance. In this case, if the head-side vertical portion 32 (liquid tube 30) connected to the head unit 20 also rotates 90 degrees to become horizontal, the liquid W will leak out from the end of the liquid tube 30 on the head unit 20 side. Therefore, it is preferable that the head-side vertical portion 32 be connected to the head unit 20 in a way that maintains a vertical state regardless of the orientation of the head unit 20, such as by a water tube holding mechanism 70 as shown in Figure 5.

[0038] The water tube holding mechanism 70 shown in Figure 5 includes a first plate 71, a second plate 72, a support shaft 73, a weight 74, and holding parts 75 and 76.

[0039] The first plate 71 is fixed to the head unit 20. The second plate 72 is positioned parallel to the first plate 71, and a support shaft 73 protruding horizontally from the first plate 71 is inserted into it, rotatably supporting this support shaft 73. The second plate 72 holds the head-side vertical portion 32 at holding parts 75 and 76. These holding parts 75 and 76 are, for example, a band wrapped around the head-side vertical portion 32 or a clamping part that grips the fitted head-side vertical portion 32. Below the second plate 72, a weight 74 is suspended by a string to maintain the posture of the second plate 72. Therefore, even if the support shaft 73 rotates in the same position as the head unit 20 rotates, the second plate 72 and the head-side vertical portion 32 held by the second plate 72 do not rotate. On the other hand, if the head unit 20 moves forward, backward, left, right, up, or down while maintaining its orientation (posture), the water pipe holding mechanism 70 and the head-side vertical portion 32 (liquid pipe 30) move together with the head unit 20.

[0040] In the example shown in Figure 4 above, as the inkjet head 21 (head unit 20) rotates, the liquid level of the liquid W reaches the upper △ zone 42. Also, as shown in Figure 6, if the user moves the inkjet head 21 (head unit 20) downwards significantly, the liquid level of the liquid W reaches the upper × zone 43. In these cases, the control unit 51 should control the audio output unit 60 to notify the user that the liquid level is in the × zone 43 or the △ zone 42. For example, the audio output unit 60 should make a "beep beep" sound to alert the user when the liquid level is in the △ zone 42, and a "beep" sound to warn the user when the liquid level is in the × zone 43.

[0041] Here, we consider a configuration in which shut-off valves 13a and 14a are provided in the ink circulation path 13 and ink circulation path 14, respectively, as shown in Figure 7. The shut-off valves 13a and 14a are examples of shut-off sections that block the ink path between the pressurized tank 11 and the negative pressure tank 12 and the inkjet head 21. In this configuration, the control unit 51 may shut off the ink path with the shut-off valves 13a and 14a when the head difference corresponding to the liquid level height detected by the liquid level sensors S1 to S4 is unacceptable (for example, when the liquid level is in the × zone 43, or in either the × zone 43 or the △ zone 42). The control unit 51 may also open the ink path with the shut-off valves 13a and 14a when the head difference corresponding to the liquid level height is acceptable (for example, when the liquid level is in the ○ zone 41, or in either the ○ zone 41 or the △ zone 42). Therefore, the shut-off valves 13a and 14a close when the head difference corresponding to the liquid level becomes unacceptable, and open when the user, notified by the aforementioned audio output unit 60 that the head difference is unacceptable, changes the height of the head unit 20 to make the head difference acceptable. The shut-off valves 13a and 13b and the liquid level sensors S1 to S4 can be operated by the built-in batteries.

[0042] In the embodiment described above, the inkjet printing apparatus 1 comprises a main unit 10, a head unit 20, and a liquid pipe 30. The main unit 10 has an ink tank (pressurized tank 11 and negative pressure tank 12) for storing ink IK. The head unit 20 has an inkjet head 21 that discharges ink IK supplied from the ink tank. The liquid pipe 30 is connected to the main unit 10 and the head unit 20, and is injected with liquid W, which represents the head difference between the ink tank and the inkjet head 21.

[0043] As a result, for example, the user can recognize the head difference between the ink tank and the inkjet head 21 simply by looking at the liquid level in the liquid tube 30. Alternatively, if the control unit 51 notifies the user of the head difference status based on the detection results of the liquid level sensors S1 to S4, the user can recognize the head difference through the notification. Therefore, according to this embodiment, the user can easily recognize the head difference between the ink tank and the inkjet head 21. As a result, even if the relative height between the head unit 20 and the main unit 10 changes during the manufacturing, transportation, or user operation (including maintenance) of the inkjet printer 1, the user can recognize whether the head difference is within an acceptable range. Therefore, it is possible to suppress ink leakage and color mixing caused by changes in the head difference to an inappropriate value, staining of the floor where the inkjet printer 1 is installed or the user with ink IK, and loss costs and recovery time for replacing or cleaning internal parts of the inkjet printer 1. Furthermore, it avoids the need for multiple workers or external equipment (special jigs, measuring instruments, etc.) to install the head unit 20 with the appropriate head difference.

[0044] Furthermore, in this embodiment, the inkjet printing apparatus 1 is further provided with a status display unit 40 that is visible along with the liquid level height of the liquid W in the liquid tube 30 and indicates the state of the head difference corresponding to the liquid level height.

[0045] This allows the user to visually identify the head difference by observing the liquid level in the liquid tube 30 and the status display unit 40. Therefore, the user can more easily recognize the head difference between the ink tank and the inkjet head 21.

[0046] Furthermore, in this embodiment, the inkjet printing apparatus 1 further includes liquid level sensors S1 to S4 for detecting the liquid level height of the liquid W in the liquid tube 30, an audio output unit 60 which is an example of an information unit for notifying the user, and a control unit 51 which controls the audio output unit 60 to notify the user of the head difference state corresponding to the liquid level height detected by the liquid level sensors S1 to S4.

[0047] As a result, the user can perceive the difference in water head between the ink tank and the inkjet head 21 by hearing the notification of the liquid level status by the audio output unit 60, without having to visually inspect the liquid tube 30 (or the liquid tube 30 and the status display unit 40). Therefore, the user can more easily perceive the difference in water head.

[0048] Furthermore, in this embodiment, the inkjet printing apparatus 1 is further equipped with shut-off valves 13a and 14a, which are examples of shut-off parts that block the ink path between the ink tank and the inkjet head 21. The control unit 51 blocks the ink path with the shut-off valves 13a and 14a when the head difference corresponding to the liquid level height detected by the liquid level sensors S1 to S4 is in an unacceptable state, and opens the ink path with the shut-off valves 13a and 14a when the head difference corresponding to the liquid level height detected by the liquid level sensors S1 to S4 is in an acceptable state.

[0049] This makes it possible to more reliably suppress, as described above, ink leakage and color mixing, staining of the floor where the inkjet printing device 1 is installed or the user with ink IK, and loss costs and recovery time, even if the head difference changes to an inappropriate value, while waiting for the head difference to be corrected to an appropriate value.

[0050] Figure 8 is a configuration diagram showing an inkjet printing apparatus 2 according to a modified example of this embodiment.

[0051] Figure 9 is a configuration diagram showing the inkjet printing apparatus 2 after the rotation of the head unit 120 in this modified example.

[0052] In this modified version, the head unit 120 has three first inkjet heads 121a, a second inkjet head 121b, and a third inkjet head 121c that eject ink IK horizontally. The first inkjet heads 121a, 2, and 3 have different heights during printing. The main unit 110 has three first pressure tanks 111a, 2, and 3 pressure tanks 111c, which have different heights, and three first negative pressure tanks 112a, 2, and 3 negative pressure tanks 112b and 3 negative pressure tanks 112c, which have different heights. In this modified version, only the differences from the inkjet printing apparatus 1 shown in Figure 1 etc. described above will be explained, and the explanation of overlapping items will be omitted.

[0053] The first pressurized tank 111a and the first negative pressure tank 112a, located at the lowest point of the main unit 110, are arranged to be vertically movable by the first drive source M1. The second pressurized tank 111b and the second negative pressure tank 112b are also arranged to be vertically movable by the second drive source M2. The third pressurized tank 111c and the third negative pressure tank 112c, located at the highest point of the main unit 110, are also arranged to be vertically movable by the third drive source M3. In other words, the relative heights of the first pressurized tank 111a and the first negative pressure tank 112a, the second pressurized tank 111b and the second negative pressure tank 112b, and the third pressurized tank 111c and the third negative pressure tank 112c are arranged to be variable. The entire main unit 110 (i.e., all of the first to third pressurized tanks 111a to 111c and the first to third negative pressure tanks 112a to 112c) are arranged to be vertically movable as a single unit by the fourth drive source M4. The first to fourth drive sources M1 to M4 are, for example, actuators such as motors.

[0054] The liquid tubes 130a, 130b, and 130c in this modified example can have the same structure as the liquid tube 30 shown in Figure 1 above, and liquid W is injected into them, but in Figure 8, the liquid tubes 130a, 130b, and 130c are shown as dashed lines. Liquid tube 130a is connected to the first inkjet head 121a, which is located at the lowest position in the head unit 120, and to the first pressurized tank 111a and the first negative pressure tank 112a, which are located at the lowest position in the main unit 110. Liquid tube 130b is connected to the second inkjet head 121b, and to the second pressurized tank 111b and the second negative pressure tank 112b. Liquid tube 130c is connected to the third inkjet head 121c, which is located at the highest position in the head unit 120, and to the third pressurized tank 111c and the third negative pressure tank 112c, which are located at the highest position in the main unit 110.

[0055] In this modified example, as shown in Figure 9, when the head unit 120 is rotated 90 degrees for maintenance, the first inkjet head 121a, the second inkjet head 121b, and the third inkjet head 121c, which are at different heights, will be at the same height. As a result, the head difference between the first to third inkjet heads 121a to 121c and the first to third pressurized tanks 111a to 111c and the first to third negative pressure tanks 112a to 112c, which are at different heights, is likely to change to an inappropriate value. In particular, the head difference between the first pressurized tank 111a and the first negative pressure tank 112a, which are located at the lowest point in the main unit 110, and the first inkjet head 121a, and the head difference between the third pressurized tank 111c and the third negative pressure tank 112c, which are located at the highest point in the main unit 110, and the third inkjet head 121c are particularly prone to change.

[0056] Therefore, the control unit 51 shown in Figure 3 may determine the height of an ink tank (at least one of the first pressurized tank 111a and the first negative pressure tank 112a, the second pressurized tank 111b and the second negative pressure tank 112b, and the third pressurized tank 111c and the third negative pressure tank 112c) that will bring the head difference to an acceptable state when the head difference corresponding to the liquid level height detected by the liquid level sensors S1 to S4 shown in Figure 1 is in an unacceptable state. The control unit 51 may then raise or lower each ink tank using the first to fourth drive sources M1 to M4 based on the determined height. Alternatively, the control unit 51 may notify the user of the determined height by the required amount of raising or lowering via the audio output unit 60. Upon receiving the notification, the user will operate the input unit 54 to raise or lower each ink tank using the first to fourth drive sources M1 to M4, or manually or automatically raise or lower the head unit 120.

[0057] Incidentally, in this modified example, as shown in Figure 8, the printing heights of the first inkjet head 121a, the second inkjet head 121b, and the third inkjet head 121c in the head unit 120 are different from each other. Also, as shown in Figure 8, the liquid tubes 130a to 130c are each of different lengths. As a result, the liquid level heights of the liquid tube 130a connected to the first inkjet head 121a, the liquid tube 130b connected to the second inkjet head 121b, and the liquid tube 130c connected to the third inkjet head 121c are different from each other, and the heights of the three status indicator units 40 (see Figure 1) connected to the liquid tubes 130a to 130c are also different from each other. In this case, it becomes difficult for the user to check the liquid level and status indicator 40. If the head difference between the heads 121a to 121c and the ink tank is the same, the liquid levels will differ. Therefore, it is advisable to install the liquid tubes 130a to 130c and the status indicator 40 so that the liquid level and the height of the status indicator 40 are the same, and to pressurize the liquid W in liquid tube 130a on the main unit 110 side. For example, as shown in Figure 10, it is advisable to place a float F, which is an example of a liquid level adjustment unit that pressurizes the liquid W in liquid tube 130a, at the liquid level on the main unit 110 side of liquid tube 130a connected to the first inkjet head 121a, which is located at the lowest position in the head unit 120. If a float F is also placed in liquid tube 130b, it is advisable to place a float F that is lighter than the float F in liquid tube 130a. In addition, it is advisable to omit the float F in liquid tube 130c or to place the lightest float F.

[0058] In the modified example described above, the control unit 51 determines the height of the ink tank (at least one example of the ink tank and the inkjet head 21) such that the head difference corresponding to the liquid level height detected by the liquid level sensors S1 to S4 is in an unacceptable state.

[0059] As a result, the control unit 51 can move each ink tank using the first to fourth drive sources M1 to M4 based on the determined height, or notify the user of the determined height by the required lifting / lowering amount using the audio output unit 60. Upon receiving the notification, the user can operate the lifting / lowering amount at the input unit 54 to raise or lower each ink tank using the first to fourth drive sources M1 to M4, or to raise or lower the head unit 120 manually or automatically. Therefore, the head difference between the ink tank and the inkjet head 21 can be set to an appropriate value.

[0060] Furthermore, in this modified example, the inkjet printing apparatus 2 further includes a float F, which is an example of a liquid level adjustment unit that pressurizes the liquid W in the liquid tubes 130a to 130c.

[0061] This allows for adjustment of the liquid level in liquid tubes 130a to 130c on the side opposite to where the float F is located, between the main unit 110 side and the head unit 120 side. Therefore, the liquid level in liquid tubes 130a to 130c can be changed to a height that is easy to see. Consequently, the user can more easily recognize the difference in water head.

[0062] In the above description, the inkjet printing apparatus 1 shown in Figure 1 includes both a status display unit 40 and liquid level sensors S1 to S4 and a control unit 51. However, for example, in an embodiment where notification to the user is omitted, the liquid level sensors S1 to S4 and the control unit 51 can be omitted. Also, in an embodiment where the user's visual confirmation of the liquid level height in the liquid tube 30 is omitted, the liquid tube 30 may be positioned in a location where the liquid level height cannot be visually confirmed, or the status display unit 40 can be omitted.

[0063] Furthermore, in the above description, the status display unit 40 and liquid level sensors S1 to S4 are located in the head-side vertical portion 32 of the liquid pipe 30 on the head unit 20 side, as shown in Figure 1. However, the status display unit 40 and liquid level sensors S1 to S4 may also be located in the main body-side vertical portion 31 of the liquid pipe 30 on the main body unit 10 side. In this case, it is preferable that the liquid pipe 30 be positioned so that at least the liquid level on the main body unit 10 side is visible to the user.

[0064] Furthermore, in the above description, as shown in Figure 1, the status display unit 40 has a circle zone 41, upper and lower triangle zones 42, and upper and lower cross zones 43. However, the triangle zone 42 may be omitted, and only the circle zone 41 and the upper and lower cross zones 43 may be present. Also, if colored areas are provided to represent each of the zones 41 to 43, it is preferable to use arbitrary colors such as blue for the circle zone 41, yellow for the triangle zone 42, and red for the cross zone 43. In addition, it is not necessary to divide each of the zones 41 to 43 into regions. For example, instead of dividing each of the zones 41 to 43 into regions, a scale representing the reference height of the liquid level and the deviation from this reference height may be provided.

[0065] Furthermore, in the above description, a water tube holding mechanism 70 shown in Figure 5 is provided to maintain the vertical position of the liquid tube 30 (head-side vertical portion 32). However, this water tube holding mechanism 70 can be omitted in configurations where the head unit 20 does not rotate. Also, the above-described configuration of the water tube holding mechanism 70 is merely an example; it is sufficient that the part fixed to the head unit 20 (first plate 71 and support shaft 73) is rotatably connected to the part that holds the liquid tube 30 (second plate 72, weight 74, and holding parts 75, 76). In addition, the weight 74 can be omitted if the center of gravity of the second plate 72 is below the support shaft 73.

[0066] Furthermore, while the above description has described an example of applying the first to fourth drive sources M1 to M4 shown in Figure 9 and the float F shown in Figure 10 to a modified example of this embodiment, for example, a drive source for moving the main unit 10 shown in Figure 1 may be provided, or a float F (liquid level adjustment unit) for pressurizing the liquid W may be provided in the liquid pipe 30 (main body side vertical portion 31) shown in Figure 1. In addition, pressurizing means other than the float F may be provided as the liquid level adjustment unit.

[0067] It should be noted that the present invention is not limited to the embodiments described above, and the components can be modified and implemented in practice without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining the multiple components disclosed in the embodiments described above. For example, all the components shown in the embodiments may be combined as appropriate. It goes without saying that various modifications and applications are possible without departing from the spirit of the invention. The invention described in the specification and drawings of this application is listed below.

[0068] <Note 1> A main unit having an ink tank for storing ink, A head unit having an inkjet head that ejects the ink supplied from the ink tank, A liquid tube is connected to the main unit and the head unit, into which a liquid representing the head difference between the ink tank and the inkjet head is injected. An inkjet printing apparatus characterized by comprising the following features.

[0069] <Note 2> The liquid pipe is further provided with a status indicator that is visible along with the liquid level of the liquid, and indicates the state of the head difference corresponding to the liquid level. An inkjet printing apparatus as described in Appendix 1, characterized by the features described herein.

[0070] <Note 3> A liquid level sensor for detecting the liquid level height in the liquid pipe, The notification unit that provides information to users, A control unit controls the notification unit to notify the user of the state of the head difference corresponding to the liquid level height detected by the liquid level sensor. An inkjet printing apparatus according to Appendix 1 or 2, further comprising the above.

[0071] <Note 4> The system further includes a blocking unit that blocks the ink path between the ink tank and the inkjet head, The control unit causes the shut-off unit to block the ink path when the head difference state corresponding to the liquid level height detected by the liquid level sensor is unacceptable, and opens the ink path to the shut-off unit when the head difference state corresponding to the liquid level height detected by the liquid level sensor is acceptable. An inkjet printing apparatus as described in Appendix 3, characterized by the features described herein.

[0072] <Note 5> If the head difference state corresponding to the liquid level height detected by the liquid level sensor is unacceptable, the control unit determines the height of at least one of the ink tank and the inkjet head such that the head difference state corresponding to the liquid level height becomes acceptable. An inkjet printing apparatus as described in Appendix 3 or 4, characterized by the above.

[0073] <Note 6> The system further comprises a liquid level adjustment unit that pressurizes the liquid in the liquid tube. An inkjet printing apparatus characterized by any one of the appendices 1 to 5. [Explanation of Symbols]

[0074] 1,2 Inkjet printing equipment 10 Main Unit 11. Pressurized tank (ink tank) 12. Negative pressure tank (ink tank) 13, 14, 15 Ink circulation path 13a, 14a Water stop valve (shut-off part) 20 Head Units 21 Inkjet Heads 30 liquid tubes 31 Vertical part of the main body 32. Vertical section on the head side 33 Connecting part 40 Status display section 41 ○ Zone 42 △ Zone 43 x Zone 51 Control Unit 52 Storage section 53 Display section 54 Input section 55 Interface section 60. Audio output unit (notification unit) 70 Water pipe holding mechanism 71 Plate 1 72 Second Plate 73 Support shaft 74 Weight 75,76 Holding part 110 Main Unit 111a First pressurized tank (ink tank) 111b Second pressurized tank (ink tank) 111c Third pressurized tank (ink tank) 112a First negative pressure tank (ink tank) 112b Second negative pressure tank (ink tank) 112c Third negative pressure tank (ink tank) 120 Head Unit 121a First inkjet head 121b Second inkjet head 121c Third inkjet head 130a,130b,130c liquid pipe F Float IK Ink M1 First drive source M2 2nd drive source M3 Third Drive Source M4 4th drive source S1 First liquid level sensor S2 Second liquid level sensor S3 Third liquid level sensor S4 4th liquid level sensor S11 Pressurized Ink Sensor S12 Negative Pressure Ink Sensor P Ink Pump W liquid

Claims

1. A main unit having an ink tank for storing ink, A head unit having an inkjet head that ejects the ink supplied from the ink tank, A liquid tube is connected to the main unit and the head unit, into which a liquid representing the head difference between the ink tank and the inkjet head is injected. An inkjet printing apparatus characterized by comprising the following features.

2. The liquid pipe is further provided with a status indicator that is visible along with the liquid level of the liquid, and indicates the state of the head difference corresponding to the liquid level. The inkjet printing apparatus according to claim 1, characterized in that it is the same as described in claim 1.

3. A liquid level sensor for detecting the liquid level height in the liquid pipe, The notification unit that provides information to users, A control unit controls the notification unit to notify the user of the state of the head difference corresponding to the liquid level height detected by the liquid level sensor. The inkjet printing apparatus according to claim 1, further comprising the following:

4. The system further includes a blocking unit that blocks the ink path between the ink tank and the inkjet head, The control unit causes the shut-off unit to block the ink path when the head difference state corresponding to the liquid level height detected by the liquid level sensor is unacceptable, and opens the ink path to the shut-off unit when the head difference state corresponding to the liquid level height detected by the liquid level sensor is acceptable. The inkjet printing apparatus according to claim 3, characterized in that it is as described above.

5. If the head difference state corresponding to the liquid level height detected by the liquid level sensor is unacceptable, the control unit determines the height of at least one of the ink tank and the inkjet head so that the head difference state corresponding to the liquid level height becomes acceptable. The inkjet printing apparatus according to claim 3, characterized in that it is as described above.

6. The system further comprises a liquid level adjustment unit that pressurizes the liquid in the liquid tube. The inkjet printing apparatus according to claim 1, characterized in that it is the same as described in claim 1.

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