Inkjet recording device

Abstract

To remove air bubbles from the reservoir of the inkjet head or to ensure complete replacement of the liquid in the reservoir. [Solution] The inkjet recording device 10 comprises an ink supply device 4, an inkjet head 31, and a head drive device 30. The inkjet head 31 is positioned above the sheet transport path and has a storage section 31B for temporarily storing ink supplied by the ink supply device 4, and a plurality of nozzles 32 for discharging the ink supplied from the storage section 31B onto a sheet being transported along a first direction. The head drive device 30 causes the inkjet head 31 to oscillate around a pivot axis 31E along a second direction intersecting the first direction, between a first position in which the plurality of nozzles 32 face the sheet transport path and a second position in which the plurality of nozzles 32 face upward.

Description

Technical Field

[0001] The present invention relates to an inkjet recording apparatus including an inkjet head that temporarily stores ink and discharges the ink from a plurality of nozzles.

Background Art

[0002] An inkjet recording apparatus forms an image on a sheet by discharging ink from a plurality of nozzles onto the sheet. The inkjet recording apparatus includes a storage unit that temporarily stores the ink, and a plurality of nozzles that discharge the ink supplied from the storage unit.

[0003] In the inkjet head, bubbles may occur in the storage unit. The bubbles in the storage unit have an adverse effect on the discharge of the ink.

[0004] For example, in order to prevent the occurrence of bubbles in the storage unit, it is known that the inkjet head forms a meniscus at an opening having a smaller opening area than the plurality of nozzles (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in the inkjet head, it is desirable that when bubbles occur in the storage unit, the bubbles can be discharged from the storage unit.

[0007] Furthermore, when the inkjet recording device is shipped, the storage unit may be filled with preservative solution. In this case, before the printing process is performed, the contents of the storage unit are replaced from the preservative solution to the ink.

[0008] On the other hand, before the inkjet recording device is transported, a process may be performed to replace the contents of the storage unit from ink to the storage liquid.

[0009] When the ink or the preservative solution is filled in the storage section, it is desirable that the process of replacing one of the ink or the preservative solution with the other be carried out reliably so that no original liquid remains in the storage section.

[0010] The object of the present invention is to provide an inkjet recording apparatus that can discharge air bubbles from the storage section of an inkjet head or reliably replace the liquid in the storage section. [Means for solving the problem]

[0011] An inkjet recording apparatus according to one aspect of the present invention comprises an ink supply device, an inkjet head, and a head drive device. The ink supply device supplies ink. The inkjet head is positioned above a sheet transport path and has a storage section for temporarily storing the ink supplied by the ink supply device and a plurality of nozzles for discharging the ink supplied from the storage section onto a sheet being transported along the sheet transport path in a first direction. The head drive device oscillates the inkjet head around a pivot axis along a second direction intersecting the first direction between a first position in which the plurality of nozzles face the sheet transport path and a second position in which the plurality of nozzles face upward. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide an inkjet recording apparatus that can discharge air bubbles from the storage section of an inkjet head or reliably replace the liquid in the storage section. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a diagram showing the configuration of an inkjet recording apparatus according to an embodiment. [Figure 2] Figure 2 is a cross-sectional view of the inkjet head in an inkjet recording apparatus according to an embodiment. [Figure 3] Figure 3 is a block diagram showing the configuration of the control device in the inkjet recording apparatus according to the embodiment. [Figure 4] Figure 4 is a diagram showing the configuration of the head drive device in an inkjet recording apparatus according to this embodiment. [Figure 5] Figure 5 shows an inkjet head held in a first position at the retracted position and a nozzle cover device in the nozzle open state in an inkjet recording apparatus according to an embodiment. [Figure 6] Figure 6 shows an inkjet head held in a second position in the retracted position and a nozzle cover device in the nozzle open state in an inkjet recording apparatus according to an embodiment. [Figure 7] Figure 7 shows the nozzle cover device in the first nozzle closed state in the inkjet recording apparatus according to the embodiment. [Figure 8] Figure 8 shows an inkjet recording apparatus when the nozzle cover device is in the first nozzle closed state. [Figure 9] Figure 9 shows the nozzle cover device in the second nozzle closed state in an inkjet recording apparatus according to an embodiment. [Figure 10] Figure 10 shows an inkjet recording device when the nozzle cover device is in the second nozzle closed state. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described below with reference to the drawings. Note that the following embodiments are merely examples of the present invention and do not limit the technical scope of the present invention.

[0015] The inkjet recording apparatus 10 according to the embodiment executes an inkjet printing process for forming an image on the sheet 9 by discharging the ink R1 onto the sheet 9. The printing apparatus 3 has a plurality of inkjet heads 31 that each discharge the ink R1 onto the sheet 9.

[0016] For example, the inkjet recording apparatus 10 is a printer, a facsimile machine, a copying machine, or a multifunction machine, etc. The sheet 9 is a sheet-like image forming medium such as paper or a resin film.

[0017] [Configuration of Inkjet Recording Apparatus 10] The inkjet recording apparatus 10 includes a sheet storage unit 12, a sheet conveyance device 2, a printing apparatus 3, and an ink supply device 4.

[0018] Furthermore, the inkjet recording apparatus 10 also includes an operation device 801, a display device 802, a control device 8, etc.

[0019] The sheet conveyance device 2, the printing apparatus 3, the ink supply device 4, and the control device 8 are housed within the main body 11 of the inkjet recording apparatus 10.

[0020] The sheet conveyance device 2 conveys the sheets 9 stored in the sheet storage unit 12 one by one along the sheet conveyance path 20. Furthermore, the sheet conveyance device 2 sends out the sheet 9 on which an image has been formed by the printing apparatus 3 from the sheet conveyance path 20. For example, the sheet conveyance device 2 sends out the sheet 9 from the sheet conveyance path 20 to a discharge tray or another device in the subsequent stage.

[0021] The sheet conveyance device 2 includes a sheet sending unit 21, a plurality of sets of conveyance roller pairs 22, a first belt conveyance unit 23, a second belt conveyance unit 24, a sending roller pair 25, etc. The sheet sending unit 21 sends out the sheets 9 from the sheet storage unit 12 one by one to the sheet conveyance path 20.

[0022] Multiple pairs of transport rollers 22 take over the transport of the sheet 9 from the sheet delivery unit 21 and transport the sheet 9 toward the first belt transport unit 23.

[0023] The first belt conveying unit 23 is located below the printing device 3. The first belt conveying unit 23 conveys the sheet 9 in a predetermined conveying direction D0.

[0024] In the following description, the direction along the transport direction D0 will be referred to as the first direction D1, and the direction intersecting the first direction D1 will be referred to as the second direction D2. In this embodiment, the second direction D2 is the direction perpendicular to the first direction D1.

[0025] In the printing device 3, the second direction D2 is the main scanning direction, and the first direction D1 is the sub-scanning direction.

[0026] In the first belt conveying unit 23, multiple tension rollers 231 support and rotate the endless first conveying belt 230. As a result, the upper surface of the first conveying belt 230 moves in the conveying direction D0. The first belt conveying unit 23 conveys the sheet 9 by placing it on the upper surface of the first conveying belt 230.

[0027] Furthermore, the first belt conveying unit 23 sends the sheet 9 from the top surface of the first conveying belt 230 to the second belt conveying unit 24.

[0028] The second belt conveying unit 24 is positioned downstream of the first belt conveying unit 23 in the conveying direction D0.

[0029] In the second belt conveying unit 24, multiple tension rollers 241 support and rotate the endless second conveying belt 240. As a result, the upper surface of the second conveying belt 240 moves in the conveying direction D0. The second belt conveying unit 24 conveys the sheet 9 by placing it on the upper surface of the second conveying belt 240.

[0030] Furthermore, the second belt conveying unit 24 feeds the sheet 9 to the feed roller pair 25. The inkjet recording device 10 may also be equipped with a drying device (not shown). The drying device dries the ink R1 on the sheet 9 that is being conveyed by the second belt conveying unit 24.

[0031] The delivery roller pair 25 is positioned downstream of the second belt conveying unit 24 in the conveying direction D0. The delivery roller pair 25 sends the sheet 9 on which the image has been formed out of the main body 11.

[0032] The ink supply device 4 supplies inks R1 of different colors to multiple inkjet heads 31. The ink supply device 4 includes multiple ink tanks 41 and an ink transport device 42.

[0033] Each of the multiple ink tanks 41 contains ink R1 of a different color. The ink supply device 42 supplies the ink R1 from each of the multiple ink tanks 41 to the multiple inkjet heads 31.

[0034] In this embodiment, the printing device 3 is equipped with four inkjet heads 31 corresponding to four inks R1: black, cyan, magenta, and yellow. The ink supply device 4 is equipped with four ink tanks 41 corresponding to the four inks R1.

[0035] [Inkjet head 31] The four inkjet heads 31 are arranged side by side in the first direction D1. Each inkjet head 31 is positioned so that its longitudinal direction aligns with the second direction D2.

[0036] The four inkjet heads 31 are positioned above the upper surface of the first conveyor belt 230. Each inkjet head 31 has an ink ejection section 31A and an ink storage section 31B (see Figure 2).

[0037] The storage section 31B temporarily stores the ink R1 supplied by the ink supply device 4. The storage section 31B has an inlet 31C for receiving the ink R1 supplied by the ink supply device 4.

[0038] Furthermore, each inkjet head 31 has a pressure regulating valve 31D that adjusts the pressure in the storage section 31B (see Figure 2). The pressure regulating valve 31D is a negative pressure regulating valve that introduces outside air into the storage section 31B when the pressure in the storage section 31B falls below a lower limit pressure. The lower limit pressure is a negative pressure. When the pressure regulating valve 31D is activated, bubbles are likely to form in the storage section 31B.

[0039] The ink ejection section 31A includes a plurality of nozzles 32, each capable of ejecting the ink (see Figure 2). The plurality of nozzles 32 are arranged along the second direction D2.

[0040] The inlet 31C and the pressure regulating valve 31D are located on the side of each inkjet head 31 opposite to the side on which the multiple nozzles 32 are formed (see Figure 2).

[0041] Multiple nozzles 32 discharge ink R1 supplied from the storage unit 31B onto a sheet 9 that is being transported along the first direction D1 on the upper surface of the first conveyor belt 230. In this embodiment, the upper surface of the first conveyor belt 230 is part of the sheet transport path 20.

[0042] Furthermore, the ink ejection section 31A includes multiple piezoelectric elements 33, multiple pressure chambers 35, and multiple diaphragms 34 (see Figure 2). Each of the multiple piezoelectric elements 33, multiple pressure chambers 35, and multiple diaphragms 34 is provided corresponding to a plurality of nozzles 32.

[0043] The storage section 31B is connected to a plurality of pressure chambers 35. The ink R1 is temporarily stored in the storage section 31B and then supplied from the storage section 31B to the plurality of pressure chambers 35.

[0044] Each of the multiple pressure chambers 35 is connected to a multiple nozzle 32. In other words, the storage section 31B is connected to the multiple nozzles 32 via the multiple pressure chambers 35.

[0045] Multiple pressure chambers 35 each form a passage for ink supplied to multiple nozzles 32. The ink R1 is temporarily stored in the storage section 31B, and then supplied from the storage section 31B to the multiple nozzles 32 through the multiple pressure chambers 35.

[0046] Each of the multiple diaphragms 34 forms part of the partition wall of each of the multiple pressure chambers 35. Each piezoelectric element 33 pressurizes the ink in the pressure chamber 35 via each of the diaphragms 34 when a drive signal is supplied to it.

[0047] The aforementioned drive signal is supplied from the control device 8 to each of the piezoelectric elements 33. Each of the piezoelectric elements 33, upon receiving the drive signal from the control device 8, pressurizes the ink supplied to the plurality of nozzles 32.

[0048] The piezoelectric element 33, to which the drive signal is supplied, vibrates with the energy of ink ejected from the corresponding nozzle 32. The ink, pressurized by the piezoelectric element 33 to which the drive signal is supplied, flows from the pressure chamber 35 to the corresponding nozzle 32 and is then ejected from the nozzle 32. Multiple nozzles 32 eject ink onto the sheet 9, thereby forming an image on the sheet 9.

[0049] The operating device 801 is a device that accepts human input. For example, the operating device 801 includes operation buttons and a touch panel. The display device 802 is capable of displaying information. For example, the display device 802 includes a display panel such as a liquid crystal panel.

[0050] [Control device 8] The control device 8 performs various data processing and controls the equipment provided by the inkjet recording device 10.

[0051] As shown in Figure 2, the control device 8 includes a CPU (Central Processing Unit) 81, RAM (Random Access Memory) 82, a secondary storage device 83, a signal interface 84, and a communication device 85, among others.

[0052] CPU81 is an example of a processor that performs various data processing and control tasks by executing computer programs.

[0053] RAM82 is a volatile memory device that can be read by a computer. RAM82 temporarily stores the computer program executed by CPU81 and the data that CPU81 outputs and references during the process of performing various operations.

[0054] The secondary storage device 83 is a non-volatile storage device that can be read by a computer. The secondary storage device 83 is capable of storing and updating the computer program and various types of data. For example, some or all of flash memory, SSD (Solid State Drive), and hard disk drive may be used as the secondary storage device 83.

[0055] The signal interface 84 converts signals output by various sensors into digital data and transmits the converted digital data to the CPU 81. Furthermore, the signal interface 84 converts control commands output by the CPU 81 into control signals and transmits the control signals to the controlled device.

[0056] The communication device 85 is capable of communicating with a host device (not shown) and other devices. The host device is an information processing device such as a personal computer or smartphone operated by a user.

[0057] For example, the CPU 81 receives a print job from the host device via the communication device 85. The printing device 3 forms the image specified by the print job on the sheet 9.

[0058] Furthermore, the control device 8 includes a drive circuit 86. The drive circuit 86 receives the control signal from the CPU 81 through the signal interface 84. The drive circuit 86 generates a drive signal corresponding to each of the plurality of piezoelectric elements 33 according to the content of the control signal, and supplies the generated drive signal to the plurality of piezoelectric elements 33. Each of the nozzles 32 ejects an amount of ink R1 corresponding to the drive signal.

[0059] The CPU 81 includes a plurality of processing modules that are realized by executing the computer program. The plurality of processing modules include a main control unit 8a and a print control unit 8b, etc.

[0060] The main control unit 8a performs control to initiate various processes in response to operations on the operating device 801, as well as control of the display device 802.

[0061] The print control unit 8b causes the sheet transport device 2 to perform the sheet transport process. Furthermore, the print control unit 8b causes the print device 3 to perform the print process in synchronization with the transport of the sheet 9 by the sheet transport device 2.

[0062] The print control unit 8b controls a plurality of piezoelectric elements 33 via the drive circuit 86, thereby causing the printing device 3 to perform the printing process.

[0063] When the temperature of ink R1 decreases, the viscosity of ink R1 increases. If the viscosity of the ink supplied to each nozzle 32 is high, the ink ejection performance from each nozzle 32 deteriorates when each piezoelectric element 33 operates.

[0064] In this embodiment, each inkjet head 31 is equipped with a heater 36 for heating the ink ejection section 31A and a temperature sensor 37 (see Figure 2). That is, the heater 36 and the temperature sensor 37 are located on each inkjet head 31.

[0065] Furthermore, the control device 8 includes a heater power supply circuit 87 that supplies power to the heater 36 (see Figure 3).

[0066] Furthermore, the multiple processing modules in the CPU 81 include a heater control unit 8c (see Figure 4). The heater control unit 8c controls the heater 36 through a heater power supply circuit 87.

[0067] The heater control unit 8c operates the heater 36, thereby shortening the first print time. The first print time is the time from when the inkjet recording device 10 receives a print request until it starts the print process.

[0068] The temperature sensor 37 detects the temperature of the ink ejection section 31A. That is, the temperature sensor 37 detects the temperature of the inkjet head 31. For example, the temperature sensor 37 is a thermistor.

[0069] The heater control unit 8c controls the heater 36 by feedback control based on the temperature detected by the temperature sensor 37 and the target temperature.

[0070] Incidentally, air bubbles may form in the storage section 31B of each inkjet head 31. These air bubbles in the storage section 31B adversely affect the ejection of ink R1.

[0071] In each inkjet head 31, it is desirable that the bubbles can be discharged from the storage section 31B when they occur within the storage section 31B. In the following description, the process of discharging the bubbles from the storage section 31B of each inkjet head 31 will be referred to as the bubble discharge process.

[0072] In addition, when the inkjet recording device 10 is shipped, the storage liquid may be filled into the storage section 31B. In this case, before the print process is executed, a process is performed to replace the storage liquid in the storage section 31B with ink R1.

[0073] On the other hand, before the inkjet recording device 10 is transported, a process may be performed to replace the ink R1 in the storage unit 31B with the storage liquid. In the following description, the process of replacing one of the ink R1 and the storage liquid in the storage unit 31B with the other will be referred to as the storage liquid replacement process.

[0074] When ink R1 or the storage solution is filled in the storage section 31B, it is desirable that the storage solution replacement process be carried out reliably so that no original liquid remains in the storage section 31B.

[0075] The inkjet recording device 10 is equipped with a configuration for performing the bubble removal process or the reliable storage liquid replacement process. The configuration will be described below.

[0076] [Head drive device 30] The inkjet recording device 10 includes a head drive device 30 that oscillates each of the multiple inkjet heads 31 (see Figures 1 and 4).

[0077] Each inkjet head 31 is supported so as to be able to pivot around each pivot axis 31E along the second direction D2 (see Figures 2 and 4). For example, each inkjet head 31 has a pivot axis 31E (see Figure 2).

[0078] The head drive unit 30 oscillates each inkjet head 31 between a first position and a second position around each of the oscillating axes 31E.

[0079] The first posture is the posture of each inkjet head 31 when the multiple nozzles 32 face the upper surface of the first conveyor belt 230 (see Figures 4 and 5). Each inkjet head 31 ejects ink R1 onto the sheet 9 when it is in the first posture.

[0080] The second orientation is the orientation of each of the inkjet heads 31 when the multiple nozzles 32 are facing upward (see Figure 6).

[0081] In this embodiment, the second orientation is one in which the multiple nozzles 32 are facing vertically upward (see Figure 6). Alternatively, the orientation of each of the inkjet heads 31 when the multiple nozzles 32 are facing diagonally upward may also be the second orientation.

[0082] In this embodiment, the head drive device 30 comprises a head support 300, a head moving mechanism 301, and a head oscillating mechanism 302 (see Figure 4). The head support 300 supports a plurality of inkjet heads 31. The head support 300 supports each inkjet head 31 so that it can oscillate around an oscillating axis 31E.

[0083] The head movement mechanism 301 moves multiple inkjet heads 31 between a print position and a maintenance position.

[0084] The print position is the position of the multiple inkjet heads 31 when their lower ends are aligned with the upper surface of the first transport belt 230 (see the multiple inkjet heads 31 shown by the dashed lines in Figures 4 and 5).

[0085] On the other hand, the maintenance position is located further from the upper surface of the first transport belt 230 than the print position (see the multiple inkjet heads 31 shown by solid lines in Figures 4 and 5). In this embodiment, the head moving mechanism 301 moves the multiple inkjet heads 31 up and down by moving the head support 300 up and down.

[0086] For example, the head movement mechanism 301 includes a first motor 301a and a first gear mechanism 301b (see Figure 4). The first gear mechanism 301b converts the rotational motion of the first motor 301a into vertical linear motion and transmits the linear motion to the head support 300.

[0087] In the example shown in Figure 4, the first gear mechanism 301b is a rack and pinion mechanism. Depending on the rotation direction of the first motor 301a, the multiple inkjet heads 31 move from one of the print position and the maintenance position to the other.

[0088] The head oscillating mechanism 302 oscillates each of the inkjet heads 31 between the first and second positions. For example, the head oscillating mechanism 302 oscillates each of the inkjet heads 31 when multiple inkjet heads 31 are in the maintenance position. The head oscillating mechanism 302 may also oscillate each of the inkjet heads 31 when multiple inkjet heads 31 are moving from one of the print position and the maintenance position to the other.

[0089] For example, the head oscillating mechanism 302 includes a second motor 302a and a second gear mechanism 302b, each supported by the head support 300 (see Figure 4). The second gear mechanism 302b transmits the rotational motion of the second motor 302a to the oscillating shafts 31E of the multiple inkjet heads 31.

[0090] Depending on the rotation direction of the second motor 302a, each inkjet head 31 oscillates from one of the first and second positions to the other.

[0091] Figure 5 shows a plurality of inkjet heads 31 held in the first position at the maintenance position. Figure 6 shows a plurality of inkjet heads 31 held in the second position at the maintenance position.

[0092] [Nozzle cover device 6] The inkjet recording device 10 further includes a nozzle cover device 6 (see Figures 1, 7, and 9). The nozzle cover device 6 has caps 61 that cover multiple nozzles 32 in each of the inkjet heads 31 (see Figures 7 and 9).

[0093] The nozzle cover device 6 can switch between a nozzle-closed state, in which the multiple nozzles 32 of each inkjet head 31 are covered with caps 61, and a nozzle-open state, in which the multiple nozzles 32 of each inkjet head 31 are open.

[0094] Figures 5 and 6 show the nozzle cover device 6 in the nozzle open state, and Figures 7 and 9 show the nozzle cover device 6 in the nozzle closed state.

[0095] Figure 7 shows the nozzle cover device 6 in the first nozzle closed state. The first nozzle closed state is a state in which the multiple nozzles 32 of each inkjet head 31 are covered by the cap 61 while the multiple inkjet heads 31 are in the first position.

[0096] Figure 8 shows the nozzle cover device 6 in the second nozzle closed state. The second nozzle closed state is a state in which the multiple nozzles 32 of each inkjet head 31 are covered by the cap 61 while the multiple inkjet heads 31 are in the second position.

[0097] The nozzle cover device 6 can be selectively switched between the nozzle open state, the first nozzle closed state, and the second nozzle closed state.

[0098] In this embodiment, the cap 61 includes a first cap 61a and a second cap 61b (see Figures 1, 7-10). The first cap 61a covers the multiple nozzles 32 of each of the multiple inkjet heads 31 when the multiple inkjet heads 31 are in the first position (see Figures 7, 8). The second cap 61b covers the multiple nozzles 32 of each of the multiple inkjet heads 31 when the multiple inkjet heads 31 are in the second position (see Figures 9, 10).

[0099] The nozzle cover device 6 includes a cap support 60, a main cap moving mechanism 62, and a sub-cap moving mechanism 63. The cap support 60 supports the cap 61. The first cap 61a and the second cap 61b are fixed to the cap support 60.

[0100] The main cap movement mechanism 62 moves the cap support 60 between a retracted position and a coverable position. Figures 5 and 6 show the state in which the cap support 60 is in the retracted position, and Figures 7 and 9 show the state in which the cap support 60 is in the coverable position.

[0101] When the cap support 60 is in the coverable position, one of the first cap 61a and the second cap 61b faces one of the multiple nozzles 32 of each of the inkjet heads 31 (see Figures 7 and 9). The retracted position is a position further away from the multiple inkjet heads 31 than the coverable position (see Figures 5 and 6).

[0102] In this embodiment, the main cap moving mechanism 62 moves the cap support 60 along the first direction D1. The main cap moving mechanism 62 moves the cap support 60 while multiple inkjet heads 31 are in the maintenance position.

[0103] For example, the main cap moving mechanism 62 comprises a base member 620, a third motor 62a, and a third gear mechanism 62b (see Figures 7 and 9). The base member 620 supports the cap support 60 and is supported so as to be movable along a first direction D1.

[0104] The third gear mechanism 62b converts the rotational motion of the third motor 62a into linear motion along the first direction D1 and transmits the linear motion to the base member 620.

[0105] In the example shown in Figures 7 and 9, the third gear mechanism 62b is a rack and pinion mechanism. Depending on the rotation direction of the third motor 62a, the cap support 60 moves from one of the retracted position and the coverable position to the other.

[0106] The base member 620 supports the cap support 60 so that it can move vertically. The sub-cap moving mechanism 63 moves the cap support 60 upward or downward when multiple inkjet heads 31 are in the maintenance position and the cap support 60 is in the coverable position.

[0107] When each of the inkjet heads 31 is in the first position, the sub-cap moving mechanism 63 moves the cap support 60 upward, causing the nozzle cover device 6 to enter the nozzle closed state (see Figures 7 and 8).

[0108] On the other hand, when each of the inkjet heads 31 is in the second position, the sub-cap moving mechanism 63 moves the cap support 60 downward, causing the nozzle cover device 6 to enter the nozzle closed state (see Figures 9 and 10).

[0109] The nozzle cover device 6 further includes a liquid suction device 64 (see Figures 1, 8, and 10). The liquid suction device 64 sucks up and collects the liquid flowing from the multiple nozzles 32 into the cap 61 when the nozzle cover device 6 is in the nozzle closed state.

[0110] For example, the liquid suction device 64 comprises a suction pump, a recovery tank, and a recovery tube. The recovery tube is connected to the cap 61 and the recovery tank. The suction pump reduces the pressure inside the recovery tank by sucking out the air inside the tank. As a result, the liquid flowing into the cap 61 flows into the recovery tank through the recovery tube.

[0111] The CPU 81 of the control device 8 includes a maintenance control unit 8d as one of the plurality of processing modules (see Figure 3). The maintenance control unit 8d controls the head drive device 30 and the nozzle cover device 6.

[0112] The maintenance control unit 8d executes either the first maintenance control or the second maintenance control when predetermined head maintenance conditions are met.

[0113] In this embodiment, the head maintenance conditions include either or both of the instruction input conditions and the temperature conditions.

[0114] The aforementioned instruction input condition is the condition that a specific instruction has been input to the operating device 801 or the communication device 85. The operating device 801 and the communication device 85 are examples of input devices, respectively.

[0115] For example, the specific instructions include an ink filling instruction, a storage solution filling instruction, and an air bubble discharge instruction. The ink filling instruction is an instruction to perform the process of replacing the storage solution in the storage section 31B with ink R1. The storage solution filling instruction is an instruction to perform the process of replacing the ink R1 in the storage section 31B with the storage solution. The air bubble discharge instruction is an instruction to perform the process of discharging air bubbles in the storage section 31B to the outside of the storage section 31B.

[0116] When the aforementioned ink filling instruction is input, the ink tank 41 is pre-installed in the ink supply device 4. On the other hand, when the aforementioned preservative filling instruction is input, a preservative tank containing the preservative is pre-installed in the ink supply device 4 in place of the ink tank 41.

[0117] The aforementioned temperature condition is that the temperature detected by the temperature sensor 37, which detects the temperature of each inkjet head 31, exceeds the allowable range. When bubbles are generated in the storage section 31B of each inkjet head 31, the temperature detected by the temperature sensor 37 tends to be higher than normal.

[0118] The aforementioned temperature conditions are examples of conditions that indicate the formation of relatively large bubbles in the storage section 31B. For example, the allowable range of the temperature detected by the temperature sensor 37 is set according to the power supplied to the heater 36.

[0119] In the following description, the ink R1 or storage solution supplied from the tank attached to the ink supply device 4 to each of the inkjet heads 31 when the head maintenance conditions are met will be referred to as the supply solution.

[0120] The following describes the case where the specific gravity of ink R1 is greater than the specific gravity of the storage solution. If the specific gravity of ink R1 is greater than the specific gravity of the storage solution, when the storage solution replacement process is performed while each inkjet head 31 is in the first position, there is a risk that the storage solution will remain in the storage section 31B.

[0121] When the instruction input condition, which is that the instruction to fill the storage solution has been input, is met, the maintenance control unit 8d executes the first nozzle maintenance control.

[0122] The first nozzle maintenance control includes a first posture transition control, a nozzle closing control, a liquid supply control, and a liquid suction control.

[0123] The first attitude transition control is a control that causes the head drive device 30 to perform an operation to hold each of the inkjet heads 31 in the first attitude at the maintenance position.

[0124] The nozzle closing control is a control that switches the nozzle cover device 6 to the nozzle closed state. When the first attitude transition control and the nozzle closing control are executed, the nozzle cover device 6 enters the first nozzle closed state (see Figures 7 and 8).

[0125] The liquid supply control and liquid suction control in the first nozzle maintenance control are performed when the nozzle cover device 6 is in the first nozzle closed state.

[0126] The liquid supply control is a control that supplies the liquid to the storage section 31B of each inkjet head 31 by operating the ink supply device 4. The suction control is a control that operates the liquid suction device 64. The maintenance control unit 8d executes the liquid supply control and the suction control in parallel.

[0127] When the first nozzle maintenance control corresponding to the instruction to fill the storage solution is executed, it is easier to maintain a state in the storage section 31B where the storage solution, which has a relatively low specific gravity, forms an upper layer and the ink R1 forms a lower layer. As a result, the storage solution is filled into the storage section 31B without any ink R1 remaining in it.

[0128] On the other hand, if the instruction input condition, which is that the ink filling instruction or the bubble discharge instruction has been input, is met, the maintenance control unit 8d executes the second nozzle maintenance control. Similarly, if the temperature condition is met, the maintenance control unit 8d also executes the second nozzle maintenance control.

[0129] The second nozzle maintenance control includes a second posture transition control, a nozzle closing control, a liquid supply control, and a liquid suction control.

[0130] The second attitude transition control is a control that causes the head drive unit 30 to perform an operation to swing each of the inkjet heads 31 from the maintenance position to the second attitude.

[0131] As the second attitude transition control and the nozzle closing control are executed, the nozzle cover device 6 enters the second nozzle closed state (see Figures 9 and 10).

[0132] The liquid supply control and liquid suction control in the second nozzle maintenance control are performed when each of the inkjet heads 31 and the nozzle cover device 6 are in the second nozzle closed state.

[0133] The maintenance control unit 8d performs the liquid supply control and the suction control in parallel.

[0134] When the second nozzle maintenance control corresponding to the ink filling instruction is executed, it is easier to maintain a state in the storage section 31B where the relatively low specific gravity storage liquid forms an upper layer and the ink R1 forms a lower layer. As a result, the ink R1 is filled into the storage section 31B without any of the storage liquid remaining in the storage section 31B.

[0135] Furthermore, when the first nozzle maintenance control corresponding to the bubble discharge instruction is executed, the bubbles float to the surface within the storage section 31B and are pushed upward by the supply liquid. As a result, the bubbles within the storage section 31B are reliably discharged to the outside of the storage section 31B through the multiple nozzles 32.

[0136] Furthermore, if the specific gravity of the storage solution is greater than the specific gravity of the ink R1, the maintenance control unit 8d performs the following control. That is, if the instruction input condition that the instruction to fill the storage solution has been input is met, the maintenance control unit 8d performs the second nozzle maintenance control. On the other hand, if the instruction input condition that the instruction to fill the ink has been input is met, the maintenance control unit 8d performs the first nozzle maintenance control.

[0137] [Notes on the invention] The following is an overview of the invention extracted from the above-described embodiments. Note that each configuration and processing function described below can be selected and combined as desired.

[0138] <Note 1> An ink supply device that supplies ink, An inkjet head is positioned above the sheet transport path and has a storage section for temporarily storing the ink supplied by the ink supply device, and a plurality of nozzles for discharging the ink supplied from the storage section onto a sheet being transported along the sheet transport path in a first direction. An inkjet recording apparatus comprising: a head drive device that oscillates the inkjet head around a pivot axis along a second direction intersecting the first direction between a first position in which the plurality of nozzles face the sheet transport path and a second position in which the plurality of nozzles face upward.

[0139] <Note 2> A nozzle cover device having a cap that covers the plurality of nozzles in the inkjet head, and capable of switching between a nozzle closed state in which the plurality of nozzles are covered by the cap and a nozzle open state in which the plurality of nozzles are open, The system comprises an ink supply device, an inkjet head, a head drive device, and a control device for controlling the nozzle cover device, The nozzle cover device is capable of covering the plurality of nozzles with the caps when the inkjet head is in the second position. The inkjet recording apparatus according to Appendix 1, wherein the control device performs the following actions when predetermined head maintenance conditions are met: control to switch the nozzle cover device to the nozzle closed state; control to cause the head drive device to swing the inkjet head to the second position; and control to operate the ink supply device when the nozzle cover device is in the nozzle closed state and the inkjet head is in the second position.

[0140] <Note 3> The head maintenance conditions are as follows: The instruction input condition is that a specific instruction has been input to the input device, The inkjet recording apparatus according to Appendix 2, which includes a temperature condition in which the temperature detected by a temperature sensor for detecting the temperature of the inkjet head exceeds an acceptable range.

[0141] <Note 4> The inkjet recording apparatus according to any one of the appendices 1 to 3, wherein the inkjet head has a pressure regulating valve for regulating the pressure in the storage section. [Explanation of Symbols]

[0142] 3: Printing device 4: Ink supply device 6: Nozzle cover device 8: Control device 10: Inkjet recording device 30: Head drive device 31: Inkjet head 31A: Ink ejection unit 31B: Storage section 31C: Inlet 31D: Pressure regulating valve 31E: Oscillating axis 32: Nozzle 33: Piezoelectric element 41: Ink Tank 42: Ink supply device 60: Cap support 61: Cap 62: Main cap movement mechanism 63: Sub-cap relocation mechanism 64:Liquid suction device 230: First conveyor belt 300: Head support 301: Head movement mechanism 302: Head oscillating mechanism D1: 1st direction D2 :Second direction

Claims

1. An ink supply device that supplies ink, An inkjet head is positioned above the sheet transport path and has a storage section for temporarily storing the ink supplied by the ink supply device, and a plurality of nozzles for discharging the ink supplied from the storage section onto a sheet being transported along the sheet transport path in a first direction. An inkjet recording apparatus comprising: a head drive device that oscillates the inkjet head around a pivot axis along a second direction intersecting the first direction between a first position in which the plurality of nozzles face the sheet transport path and a second position in which the plurality of nozzles face upward.

2. A nozzle cover device having a cap that covers the plurality of nozzles in the inkjet head, and capable of switching between a nozzle closed state in which the plurality of nozzles are covered by the cap and a nozzle open state in which the plurality of nozzles are open, The system comprises an ink supply device, an inkjet head, a head drive device, and a control device for controlling the nozzle cover device, The nozzle cover device is capable of covering the plurality of nozzles with the caps when the inkjet head is in the second position. The inkjet recording apparatus according to claim 1, wherein the control device performs the following actions when predetermined head maintenance conditions are met: control to switch the nozzle cover device to the nozzle closed state; control to cause the head drive device to swing the inkjet head to the second position; and control to operate the ink supply device when the nozzle cover device is in the nozzle closed state and the inkjet head is in the second position.

3. The head maintenance conditions are as follows: The instruction input condition is that a specific instruction has been input to the input device, The inkjet recording apparatus according to claim 2, further comprising the temperature condition that the temperature detected by the temperature sensor for detecting the temperature of the inkjet head exceeds an acceptable range.

4. The inkjet recording apparatus according to any one of claims 1 to 3, wherein the inkjet head has a pressure regulating valve for regulating the pressure in the storage section.

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