Inkjet recording device

Abstract

To provide an inkjet recording device which can facilitate cleaning of a print head and easily recover a solvent (a cleaning fluid) used for the cleaning.SOLUTION: An inkjet recording device includes: a print head which receives supply of an ink to perform printing; and a body which includes an ink container for storing an ink and a solvent container for storing a solvent and supplies the ink in the ink container to the print head. The inkjet recording device includes a washing tank, a cleaning nozzle, and a recovery container. The print head is set within the washing tank, the solvent is jetted from the cleaning nozzle to wash the print head, and the solvent after washing is recovered by the recovery container.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an inkjet recording apparatus that continuously ejects ink from nozzles to perform printing on a print-receiving medium. [Background technology]

[0002] As a technique related to nozzle cleaning in this technical field, the technique described in JP 2002-103636 A (Patent Document 1) is known. Patent Document 1 describes that "A cleaning jet is installed downstream of the ink nozzle to be cleaned in the print head, offset to the side of the nozzle. When the inkjet stops, a predetermined amount of solvent is sprayed by this cleaning jet, which hits the nozzle at a predetermined angle. In this way, the front surface of the droplet generator is cleaned (washed), and ink residue is discharged toward the opposite side of the housing. Dry compressed air is then blown through the cleaning jet toward the ink nozzle, drying the front of the nozzle, and the ink residue is attached to the side of the housing."

[0003] Another technique related to nozzle cleaning is known, which is described in JP 2015-136934 A (Patent Document 2). Patent Document 2 describes that "a cleaning nozzle, i.e., an ASC nozzle, is provided to clean the nozzle of the head. This ASC nozzle is used to clean the nozzle outlet by spraying a cleaning liquid (solvent) from the ASC nozzle. Specifically, the ASC nozzle (cleaning nozzle) is disposed inside the head so as to face the nozzle outlet. This ASC nozzle (cleaning nozzle) is connected to the solvent line and the solvent tank via an openable and closable air valve. When cleaning the nozzle, the air valve, which is an open / close valve, is opened, and the solvent supplied from the solvent tank is sprayed from the ASC nozzle." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-103636 A [Patent Document 2] JP 2015-136934 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the technology of Patent Document 1, ink residues adhering to the nozzles inside the print head end up adhering to a part other than the nozzles (the side of the print head housing) when the print head is washed (cleaned). This requires an operator to manually wash that part separately with a solvent, which is a cumbersome task. Furthermore, Patent Document 1 does not describe how to dispose of the solvent after cleaning.

[0006] Furthermore, the technology of Patent Document 2 involves spraying a solvent (cleaning liquid) from a cleaning nozzle (ASC nozzle) provided inside the print head to clean the nozzle outlet, but similar to Patent Document 1, manual work is required to remove ink residue that adheres to the print head by cleaning. Patent Document 2 also makes no mention of how to dispose of the solvent (cleaning liquid) after cleaning the print head.

[0007] Therefore, an object of the present invention is to provide an inkjet recording device and a control method for an inkjet recording device that can clean a print head and easily recover the solvent (cleaning liquid) used to clean the print head. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, one example of the present invention is an inkjet recording apparatus having a print head which receives a supply of ink and performs printing, and a main body which includes an ink container for storing ink and a solvent container for storing a solvent, and which supplies the ink in the ink container to the print head, the print head being equipped with a nozzle which converts the ink into ink particles and ejects them, a charging electrode which charges the ink particles ejected from the nozzle in accordance with the content to be printed, a deflection electrode which changes the flight direction of the charged ink particles, and a gutter which collects the ink particles which do not contribute to the printing, the inkjet recording apparatus also comprising: a cleaning tank for setting the print head, a cleaning nozzle which sprays the solvent towards the print head set in the cleaning tank to clean it, and a head cleaning unit which includes a recovery container provided at the bottom of the cleaning tank for recovering the solvent after cleaning, and a drive unit which supplies the solvent to the cleaning nozzle.

[0009] Another example of the present invention is a control method for an inkjet recording device having a print head which receives a supply of ink to print, and a main body which includes an ink container for storing ink and a solvent container for storing solvent, and which supplies the ink in the ink container to the print head, the control method for an inkjet recording device comprising: setting the print head inside a cleaning tank equipped with a cleaning nozzle for spraying the solvent, and then spraying the solvent from the cleaning nozzle to clean the print head, and recovering the solvent after cleaning in a recovery container provided at the bottom of the cleaning tank. Effect of the Invention

[0010] According to the present invention, it is possible to provide an inkjet recording device and a control method for an inkjet recording device that can easily clean a print head and easily recover the solvent (cleaning liquid) used to clean the print head. [Brief description of the drawings]

[0011] [Figure 1]FIG. 1 is a perspective view showing a usage state of an inkjet recording apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing a state in which a print head is set in a cleaning unit in the first embodiment. [Diagram 3] FIG. 2 is a perspective view showing a state in which a head cleaning unit is fixed to a main body in the first embodiment. [Figure 4] FIG. 2 is a diagram showing a path configuration of the inkjet recording apparatus in the first embodiment. [Diagram 5] FIG. 4 is a diagram showing a path configuration of the inkjet recording apparatus in a state where a head cleaning unit is removed in the first embodiment. [Figure 6] FIG. 4 is a diagram showing a path configuration of a head cleaning unit in a state where the head cleaning unit is removed from the main body of the inkjet recording apparatus in the first embodiment. [Figure 7] 4 is a fluid path diagram showing, by thick lines, the flow of liquid when a head cleaning process is being performed in the first embodiment. FIG. [Figure 8] 4 is a flow path diagram showing, by thick lines, the air flow when a head drying process is performed in Example 1. FIG. [Figure 9] 4 is a fluid path diagram showing the flow of ink and solvent by bold lines when the ink and solvent are being replenished in the first embodiment. FIG. [Figure 10] 4 is a fluid path diagram showing the flow of ink by a thick line when an ink circulation process is performed in the first embodiment. FIG. [Figure 11] FIG. 2 is a configuration diagram of a print head in the first embodiment. [Figure 12] FIG. 2 is a configuration diagram of a head cleaning unit in the first embodiment. [Figure 13] 4 is a cross-sectional view of the head cleaning unit in a state in which a print head is set in the head cleaning unit in the first embodiment. FIG. [Figure 14] FIG. 14 is an enlarged view of the print head and its periphery in FIG. 13. [Figure 15] 4 is a cross-sectional view of the head cleaning unit, showing by thick lines the flow of liquid inside the head cleaning unit when a head cleaning process is being performed in the first embodiment. FIG. [Figure 16] In the first embodiment, detection of the liquid level in the collection container in each state is shown. [Figure 17] 4 is a cross-sectional view of the head cleaning unit when a liquid draining operation is being performed on the collection container in the first embodiment. FIG. [Figure 18] FIG. 11 is an external perspective view of an inkjet recording apparatus according to a second embodiment of the present invention. [Figure 19] FIG. 11 is a perspective view showing a state in which a print head is set in a cleaning unit in an inkjet recording apparatus according to a second embodiment. [Figure 20] FIG. 11 is a diagram showing a path configuration of an inkjet recording apparatus in a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Specific embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments described below. In addition, in each of the drawings, the same devices are given the same numbers (reference characters), and descriptions of devices that have already been described may be omitted.

[0013] Example 1 <Usage status> First, the usage state of an inkjet recording apparatus 600 in a first embodiment of the present invention will be described with reference to Figs. 1 to 3. Fig. 1 is a perspective view showing the usage state of the inkjet recording apparatus 600 in this embodiment, and Fig. 2 is a perspective view showing the state in which the print head 2 is attached to the head cleaning unit 4 in the inkjet recording apparatus 600 in this embodiment. Fig. 3 is a perspective view showing the state in which the head cleaning unit 4 is fixed to the main body 1 in the inkjet recording apparatus 600.

[0014] First, as shown in FIG. 1, an inkjet recording device 600 according to this embodiment includes a main body 1, a print head 2 connected to the main body 1 by a conduit (for the print head) 5, and a head cleaning unit 4 connected to the main body 1 by a conduit 6 for the head cleaning unit.

[0015] Inkjet recording device 600 is installed on a production line in a factory where food, beverages, etc. are produced, and main body 1 is installed in a location where the space required for regular maintenance work can be secured. Print head 2 is fixed to print head fixing metal fittings 13 installed near belt conveyor 11, and installed in close proximity to print objects 12A-12B fed in the direction of arrow XX on the production line such as belt conveyor 11. In addition, protective cover 17 is attached to print head 2 for the purpose of protecting the parts inside print head 2.

[0016] In this inkjet recording device 600, a control unit 10 (whose specific configuration is not shown) installed inside the main body 1 controls the amount of charge and timing of charging ink droplets 68B ejected from nozzles 21 attached to the print head 2. That is, the control unit 10 controls the ink droplets 68B charged and deflected while the print target (before printing) 12A passes near the print head 2, so that the ink droplets 68B are attached to the print target (during printing) 12B to perform printing. The control unit 10 also controls solenoid valves, pumps, and the like installed inside the main body 1 to control the flow of ink and the flow of solvent. The control unit 10 can use a computer. Specifically, the control unit 10 can be composed of a microprocessing unit (MPU), a memory that stores programs for the operation of the MPU and data and information required for the operation, and a print drive unit that operates the print head and components inside the main body 1 according to instructions from the MPU. Here, details of the control unit 10 are omitted.

[0017] The head cleaning unit 4 is installed around the print head 2. In this embodiment, the head cleaning unit 4 is fixed by combining a fixing jig fitting portion 93 attached to the head cleaning unit 4 with a fixing jig A (for conveyor) 92 attached to the belt conveyor 11. The head cleaning unit 4 also has a print head insertion portion 72A, which is an opening for inserting the print head 2 into the head cleaning unit 4.

[0018] Furthermore, the head cleaning unit 4 has a start button 63 for starting the cleaning process of the print head 2, a stop button 64 for stopping the cleaning process of the print head 2, and a display unit 65 for notifying the operator of confirmation messages, warnings, abnormalities, and other alarms.

[0019] The main body 1 has a fixing jig (for main body) 91 for fixing the head cleaning unit 4, and the head cleaning unit 4 can be used by removing it from the fixing jig (for conveyor) 92 and attaching it to the fixing jig (for main body) 91. In this embodiment, the head cleaning unit 4 is fixed to the belt conveyor 11, but in the inkjet recording device 600 of this embodiment, the head cleaning unit 4 can be freely attached to a location that is easy for the user to operate.

[0020] 2, the state in which the print head 2 is set in the head cleaning unit 4 in the inkjet recording device 600 will be described. The print head 2 is set by inserting the tip of the print head 2 into the print head insertion section 72A of the head cleaning unit 4. By setting the print head 2 in the head cleaning unit 4 in this way, the inkjet recording device 600 in this embodiment can clean the print head 2 with a solvent (cleaning liquid) supplied from the main body 1 side via a conduit 6.

[0021] The length of the conduit (for the head cleaning unit) 6 connecting the main body 1 and the head cleaning unit 4 is preferably the same as or longer than the conduit (for the print head) 5 connecting the main body 1 and the print head 2 of the inkjet recording device. This is to ensure the freedom of arrangement of the head cleaning unit 4.

[0022] Next, a state in which the head cleaning unit 4 is fixed to the main body 1 in the inkjet recording device 600 will be described with reference to Fig. 3. The head cleaning unit 4 can be fixed to the main body 1 by combining a fixing jig 91 attached to the main body 1 with a fixing jig fitting portion 93. By making it possible to fix the head cleaning unit 4 to the main body 1, it becomes possible to install the head cleaning unit 4 even when there is no space to install the head cleaning unit 4 on the belt conveyor 11 or the like.

[0023] <Route configuration> Next, the path configuration of the inkjet recording apparatus 600 in this embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram showing the overall path configuration of the inkjet recording apparatus 600 in this embodiment.

[0024] First, the ink supply paths (paths 801 to 803) of the inkjet recording apparatus 600 in this embodiment will be described. In Fig. 4, the main body 1 is provided with an ink container 31 that holds circulating ink 68A. The ink container 31 is provided with a liquid level sensor 31A that detects whether the liquid in the ink container 31 has reached a reference liquid level, which is an appropriate amount to be held inside.

[0025] The ink container 31 is connected to a path (for supply) 801 at a portion immersed in the ink 68A, and an electromagnetic valve (for supply) 49 for opening and closing the path is provided midway along the path 801. Furthermore, the path 801 is connected via a junction path 901 to a pump (for supply) 34 that is provided in a path 802 and is used to suck and pump the ink 68A. The output side of the pump (for supply) 34 is connected to a filter (for supply) 39 that removes foreign matter mixed in the ink 68A.

[0026] The filter (for supply) 39 is connected to a pressure regulating valve 46 that adjusts the pressure of the ink 68A pumped from the pump (for supply) 34 to an appropriate pressure for printing, and the pressure regulating valve 46 is connected to a pressure sensor 47 that measures the pressure of the ink 68A supplied to the nozzles 21. A path 802 in which the pressure sensor 47 is arranged passes through a conduit (for print head) 5, and is connected to a switching valve 26 provided in the print head 2 and for controlling whether or not the ink 68A is supplied to the nozzles 21.

[0027] The switching valve 26 is connected via a path 803 to a nozzle 21 having an outlet 21A for ejecting ink 68A. The switching valve 26 is a three-way solenoid valve, and an ink supply path 802 and a nozzle cleaning path 812 are connected to the switching valve 26, so that the supply of ink 68A and the supply of solvent 69A to the nozzle 21 can be switched. In the straight direction of the outlet 21A of the nozzle 21, there are arranged a charging electrode 23 for adding a predetermined amount of charge to the ink particles 68B, a deflection electrode 24 for deflecting the ink particles 68B used for printing, and a gutter 25 for capturing the ink particles 68B that are not used for printing and fly straight without being charged or deflected.

[0028] Next, the ink recovery path 804 of the inkjet recording apparatus 600 in this embodiment will be described. In Fig. 4, the gutter 25 is connected to the path 804, and a charge sensor 48 is disposed in the path 804 for detecting whether ink particles 68B to which an electric charge has been added by the charging electrode 23 are being recovered. The path 804 passes through a conduit (for print head) 5 and is connected to a filter (for recovery) 40 that removes foreign matter mixed in the ink disposed in the main body 1, and the filter (for recovery) 40 is connected to an electromagnetic valve (for recovery) 50 that opens and closes the path.

[0029] The solenoid valve (for recovery) 50 is connected to a pump (for recovery) 35 that sucks up the ink particles 68B captured by the gutter 25, and the pump (for recovery) 35 is connected to the ink container 31. By opening the solenoid valve 50 and driving the pump 35, the ink particles 68B captured by the gutter 25 are collected in the ink container 31. The ink container 31 is also connected to a path 805 in an upper space that does not contact the ink 68A, and the path 805 is configured to communicate with the outside of the main body 1.

[0030] Next, the ink circulation paths (paths 806-807) of the inkjet recording device 600 in this embodiment will be described. In addition to the path 803 for supplying ink, the nozzles 21 provided in the print head 2 are connected to a path 806 that passes through a conduit (for print head) 5. In this path 806, a solenoid valve (for circulation) 51 that is provided in the main body 1 and opens and closes the flow path is disposed.

[0031] The solenoid valve (for circulation) 51 is connected to a path 807 via a junction path 902, and a pump (for circulation) 36 that sucks ink from the nozzles 21 is disposed in the path 807. The pump (for circulation) 36 is configured to be connected to the ink container 31.

[0032] Next, the viscosity measurement path (paths 808 and 807) of the inkjet recording device 600 in this embodiment will be described. In FIG. 4, the ink container 31 is connected to the path 808 at a portion immersed in the ink 68A. The path 808 is connected to a viscosity measuring device 45 via a path 801 in order to grasp the viscosity of the ink 68A in the ink container 31. The viscosity measuring device 45 is connected to an electromagnetic valve (for viscosity measurement) 52 that opens and closes the path. The electromagnetic valve (for viscosity measurement) 52 is connected to a pump (for circulation) 36 arranged in the path 807 via a junction path 902. This allows the ink 68A in the ink container 31 to be circulated through the viscosity measurement path, and the viscosity of the ink 68A can be measured. After the measurement, the viscosity is input to the control unit 10 shown in the figure and used to control the viscosity of the ink 68A in the ink container 31.

[0033] Next, the solvent supply path (paths 809-810) of the inkjet recording device 600 in this embodiment will be described. In FIG. 4, the main body 1 is provided with a solvent container 33 that holds a solvent 69A to be used for supplying a solvent to the ink container 31, cleaning the nozzle, or cleaning the head. The solvent container 33 is connected to a path 809 at a portion immersed in the solvent 69A, and a pump (for solvent) 37 used for sucking and pumping the solvent is disposed in the path 809. The pump (for solvent) 37 is connected to a branch path 903 to change the supply destination of the solvent 69A depending on the purpose. The branch path 903 is connected to an electromagnetic valve (for solvent supply) 53 to open and close the flow path disposed in the path 810 in the solvent supply path, and the electromagnetic valve (for solvent supply) 53 is configured to be connected to the ink container 31.

[0034] Next, the ink supply path 811 of the inkjet recording device 600 in this embodiment will be described. In FIG. 4, the main body 1 is provided with an auxiliary ink container 32 that holds refill ink 68C. The auxiliary ink container 32 is connected to the path 811 at a portion immersed in the ink 68C. The path 811 is connected to an electromagnetic valve (for ink supply) 54 that opens and closes the path, and the electromagnetic valve (for ink supply) 54 is connected via a junction path 901 to a pump (for supply) 34 that is installed in a path 802 and is used to suck and pump the ink 68C. The ink 68C in the auxiliary ink container 32 is refilled into the ink container 31 via the nozzle 21, the gutter 25, the path 804, the electromagnetic valve 50, and the pump 35.

[0035] Next, the nozzle cleaning paths (paths 809 and 812) of the inkjet recording apparatus 600 in this embodiment will be described. In FIG. 4, the pump (for solvent) 37 disposed in the path 809 is connected to the path 812 via a branch path 903. The path 812 is connected to an electromagnetic valve (for nozzle cleaning) 55 for opening and closing the flow path. The electromagnetic valve (for nozzle cleaning) 55 is connected to a filter (for nozzle cleaning) 41 for removing foreign matter mixed in the solvent 69A. The filter (for nozzle cleaning) 41 is provided in the print head 2 via the path 812 passing through the conduit (for print head) 5, and is connected to a switching valve 26 for controlling whether or not the solvent 69A for cleaning is sent to the nozzle 21.

[0036] Next, the head cleaning paths (path 809, paths 821-822) of the inkjet recording apparatus 600 in this embodiment will be described. In Fig. 4, the pump (for solvent) 37 is connected to the path 821 via a branch path 903, and the path 821 is connected to the path 822 via a connection part (for head cleaning) 59A and a joint (for head cleaning) 60A for relaying with the drive unit 3 incorporated inside the main body 1. In the path 822, an electromagnetic valve (for nozzle cleaning) 56 for opening and closing the flow path is disposed, and the electromagnetic valve (for nozzle cleaning) 56 is connected to a filter (for head cleaning) 42 for removing foreign matter mixed in the solvent 69A.

[0037] The filter (for head cleaning) 42 is provided in the head cleaning unit 4 via a path 822 passing through the conduit (for head cleaning unit) 6, and is connected to a filter (for cleaning nozzle) 43 in order to remove foreign matter that may initially get mixed into the path 822. The output side of the filter (for cleaning nozzle) 43 is connected to a cleaning nozzle 74 provided inside a cleaning tank 71 of the head cleaning unit 4. Here, the space inside the cleaning tank 71 is configured to communicate with a collection container 73 installed below.

[0038] Next, the solvent reuse path (paths 823-824 and path 807) of the inkjet recording device 600 in this embodiment will be described. In FIG. 4, the head cleaning unit 4 is provided with a recovery container 73 that holds the recovered solvent 69B after head cleaning that flows in under its own weight after being used for head cleaning. A filter (for recovery container) 77 is attached to the recovery container 73 so that foreign matter mixed in during head cleaning does not flow into the path 823. The recovery container 73 is connected to the path 823 at a portion immersed in the recovered solvent 69B. The path 823 passes through a conduit (for head cleaning unit) 6 and is connected to a filter (solvent reuse) 44 in the drive unit 3 inside the main body 1. This filter 44 is for preventing fine foreign matter contained in the recovered solvent 69B from being mixed into the ink 68A.

[0039] Furthermore, the output side of the filter (solvent reuse) 44 is connected to the solenoid valve (solvent reuse) 57 for opening and closing the flow path by a path 823. The path 823 in which the solenoid valve (solvent reuse) 57 is arranged is connected to a path 824 via a connection part (solvent reuse) 59B and a connection part (solvent reuse) 60B for relaying between the main body 1 and the drive unit 3. The path 824 is connected to the pump (for circulation) 36 arranged in the path 807 via a junction path 902. This makes it possible for the recovered solvent 69B held in the recovery container 73 to be replenished to the ink container 31 in the main body 1 via the drive unit 3. This replenishment makes it possible to adjust the ink concentration (viscosity), and the ink can be reused for viscosity adjustment. That is, when the viscosity detected by the viscosity measuring device 45 becomes equal to or greater than a predetermined value, the control unit 10 supplies the solvent 69B used for cleaning the inside of the recovery container 73 to the ink container 31 via the path 823, the filter 44, the solenoid valve 57, the connection part 60B, the branch 902 of the path 824, the path 807, and the pump 36.

[0040] Next, a head dry air path 825 of the inkjet recording apparatus 600 in this embodiment will be described. In Fig. 4, the drive unit 3 housed in the main body 1 is provided with a pump (for supplying dry air) 38 used to suck and pump air, and the pump (for supplying dry air) 38 forms an air suction port communicating with the inside of the main body 1. The pump (for supplying dry air) 38 is connected to an air nozzle 75 provided in the cleaning tank 71 of the head cleaning unit 4 via a path 825 passing through the inside of the conduit (for head cleaning unit) 6.

[0041] <Head cleaning unit built-in structure> The structure of incorporating the head cleaning unit 4 into the inkjet recording apparatus 600 in this embodiment will be described with reference to Figs. 4 to 6. Fig. 4 is a path configuration diagram showing a state in which the head cleaning unit 4 is incorporated into the inkjet recording apparatus 600 in this embodiment. Fig. 5 is a path configuration diagram showing a state in which the head cleaning unit 4 is not incorporated into the inkjet recording apparatus 600 in this embodiment. And Fig. 6 is a path configuration diagram of the head cleaning unit 4 and the drive unit 3.

[0042] 5, the main body 1 of the inkjet recording apparatus 600 is in a state in which the head cleaning unit 4 and the drive unit 3 have been removed. In a path 821 connected to the cleaning nozzle 74 of the head cleaning unit 4, a sealing plug 61A is attached to a connection part (for head cleaning) 59A in order to close the flow path. In addition, in a path 824 connected to the collection container 73 of the head cleaning unit 4, a sealing plug 61B is attached to a connection part (for reusing solvent) 59B in order to close the flow path. In addition, a storage area 58 for arranging the drive unit 3 is secured in the main body 1.

[0043] 6 shows the head cleaning unit 4 removed from the main body 1 of the inkjet recording apparatus 600. The head cleaning unit 4 is connected to the drive unit 3 by a conduit (for head cleaning unit) 6. The drive unit 3 is configured by incorporating a pump (for supplying dry air) 38, an electromagnetic valve (for head cleaning) 56, an electromagnetic valve (for reusing solvent) 57, a filter (for head cleaning) 42, and a filter (for reusing solvent) 44.

[0044] In this way, in the inkjet recording device 600 of this embodiment, the main body 1 and the head cleaning unit 4 can be separated. This makes it easy to carry the head cleaning unit 4, the drive unit 3, and the conduit 6 connecting these drive units 3, 4 as a single head cleaning device. When cleaning the print head 2, this head cleaning device is attached to the main body 1 and used.

[0045] <Operation and liquid flow> Next, the operation of the inkjet recording apparatus 600 in this embodiment will be described.

[0046] FIG. 7 is a fluid path diagram showing, by bold lines, the flow of solvent and the flow of air when a head cleaning process is being performed in the inkjet recording apparatus 600 according to the first embodiment. 7, the inkjet recording apparatus 600 is in a state in which the print head 2 is set (inserted) in the head cleaning unit 4 for cleaning. In the head cleaning path (path 809, paths 821-822), the solenoid valve (for head cleaning) 56 is energized to open the flow path and operate the pump (for solvent) 37, thereby making it possible to supply the solvent to the head cleaning unit 4, as indicated by the bold line of the arrow A. In other words, the solvent 69A contained in the solvent container 33 of the main body 1 can be supplied to the cleaning nozzle 74 installed in the cleaning tank 71 of the head cleaning unit 4.

[0047] The cleaning nozzle 74 sprays the solvent 69A toward the print head to clean the print head. Specifically, part of the solvent 69A supplied to the cleaning nozzle 74 is discharged toward the nozzle 21 surrounded by the protective cover 17 of the print head 2 as shown by the bold line of the arrow B, and the other part is discharged toward the protective cover 17 on the outside of the print head 2 as shown by the bold line of the arrow C. The solvent 69A discharged from the cleaning nozzle 74 as shown by the bold line of the arrow B washes the components such as the nozzle 21, the charging electrode 23, the deflection electrode 24, and the gutter 25 assembled inside the print head 2, and drips downward by gravity as shown by the bold line of the arrow E. The solvent 69A that has dripped to the bottom of the cleaning tank 71 flows toward the recovery container 73 as shown by the bold line of the arrow F, and is stored inside the recovery container 73 as recovered solvent 69B.

[0048] In the ink circulation paths (paths 806-807), the solenoid valve (for circulation) 51 is energized to open the flow path and operate the pump (for circulation) 36, whereby a portion of the solvent 69A that hits the nozzle 21 is sucked from the nozzle 21A and collected in the ink container 31 of the main body 1, as indicated by the bold line of the arrow G. In this way, in the head cleaning process, the inside of the nozzle 21 and the ink circulation paths 806-807 can also be cleaned with the solvent 69A.

[0049] Furthermore, in the ink recovery path 804, the solenoid valve (for recovery) 50 is energized to open the flow path and operate the pump (for recovery) 35, whereby a portion of the solvent 69A that hits the gutter 25 is sucked out of the gutter 25 and recovered in the ink container 31 of the main body 1, as indicated by the bold line of the arrow H. In this way, in the head cleaning process, the inside of the gutter 25 and the ink recovery path 804 can also be cleaned with the solvent 69A.

[0050] Next, Fig. 8 is a fluid path diagram showing with bold lines the air flow when a head drying process is being performed in the inkjet recording device 600 of this embodiment. In Fig. 8, the inkjet recording device 600 is in a state in which the print head 2 is set in the head cleaning unit 4, and is adapted to carry out a head drying process after the head cleaning process is completed. In the head cleaning path 825, compressed air is supplied to the air nozzle 75 assembled in the cleaning tank 71 of the head cleaning unit 4, as shown by the bold line of the arrow J, by operating the pump (for supplying dry air) 38 installed in the main body 1.

[0051] Some of the air supplied to air nozzle 75 is discharged toward the charged electrode 23 surrounded by protective cover 17 of print head 2, as indicated by the thick line of arrow K, and the other portion is discharged toward the protective cover 17 on the outside of print head 2, as indicated by the thick line of arrow L. The air discharged from air nozzle 75, as indicated by the thick line of arrow K, dries components assembled inside print head 2, such as the nozzle 21, charged electrode 23, deflection electrode 24, and gutter 25.

[0052] In the ink recovery path 804, the solenoid valve (for recovery) 50 is energized to open the flow path, and the pump (for recovery) 35 is operated, so that a part of the air is sucked from the gutter 25 and sucked and pressure-fed to the ink container 31 of the main body 1, as shown by the thick line of the arrow M. In addition, in the ink circulation path (paths 806-807), the solenoid valve (for circulation) 51 is energized to open the flow path, and the pump (for circulation) 36 is operated, so that a part of the air is sucked from the nozzle 21 and sucked and pressure-fed to the ink container 31 of the main body 1, as shown by the thick line of the arrow N. Then, the air that has flowed into the ink container 31 is exhausted to the outside of the main body 1 from the exhaust path 805, as shown by the thick line of the arrow P. In this way, by sucking air from the gutter 25 and the nozzle 21 during the head drying process, the amount of solvent gas discharged around the head cleaning unit 4 can be reduced. If the flow rate of air sucked in from inside the cleaning tank 71 by the gutter 25 and nozzle 21 is greater than the flow rate of air supplied from the air nozzle 75 into the cleaning tank 71, the diffusion of solvent gas around the head cleaning unit 4 can be minimized.

[0053] Next, Fig. 9 is a fluid path diagram showing the flow of ink, solvent, and air with thick lines when the ink 68A circulation control, the ink 68C supply control, and the solvent 69A-69B supply control are performed during operation in the inkjet recording device 600 of this embodiment. In Fig. 9, the inkjet recording device 600 shows that the print head 2 is removed from the head cleaning unit 4 and is in a state where printing is possible. In the ink supply paths 801-803, the solenoid valve (for supply) 49 is energized to open the flow path, and the pump (for supply) 34 is operated, so that the ink 68A stored in the ink container 31 of the main body 1 is supplied to the nozzle 21 of the print head 2 as shown by the thick lines of the arrows Q and R, and is ejected from the nozzle 21 as ink droplets 68B.

[0054] In the ink recovery path 804, the solenoid valve (for recovery) 50 is energized to open the flow path and the pump (for recovery) 35 is operated, whereby the ink particles 68B and the air around the print head 2 are sucked through the gutter 25 and sucked and pumped into the ink container 31 of the main body 1, as indicated by the bold line of the arrow S. In the ink recovery path 804, the ink 68A and the air flow in a gas-liquid mixture, so that the solvent component of the ink 68A dissolves in the air, and the air becomes a solvent gas and flows into the ink container 31. The ink 68B that flows into the ink container 31 is contained at the bottom, and the air that has become a solvent gas is discharged to the outside of the main body 1 as the solvent gas, as indicated by the arrow T.

[0055] In the inkjet recording device 600, the solvent component in the ink 68A is discharged outside the device as a solvent gas, so that the ratio of the solvent component in the ink 68A decreases as the operation time increases, and the concentration of the ink 68A becomes high. Therefore, in the viscosity measurement paths 808 and 807, the solenoid valve (for viscosity measurement) 52 is energized to open the flow path, and the pump (for circulation) 36 is operated to send the ink 68A in the ink container 31 to the viscosity measuring device 45 as shown by the arrows V and W, and to measure the concentration of the ink 68A periodically. The measured viscosity is input to the control unit 10. As a result, the control unit 10 controls the ink container 31 to be replenished with the ink 68C in the auxiliary ink container 32 when the concentration of the ink 68A is low, and controls the ink container 31 to be replenished with the recovered solvent 69B in the recovery container 73, or to be replenished with the solvent 69 in the solvent container 33 when the concentration of the ink 68A is high.

[0056] In the ink supply paths (paths 811 and 802), the solenoid valve (for ink supply) 54 is energized to open the path and the solenoid valve (for supply) 49 is de-energized to close the path, and the pump (for supply) 34 is operated to supply ink 68C from the auxiliary ink container 32 to the nozzle 21 and eject it from the nozzle 21 as ink droplets 68B. Then, the ink 68C is replenished to the ink container 31 via the ink recovery path 804.

[0057] In the solvent reuse paths (823-824 and 807), when the concentration of the ink 68A is high, the solenoid valve (for solvent reuse) 57 is energized to open the flow path, and the pump (for circulation) 36 is operated, so that the recovered solvent 69B stored in the recovery container 73 of the head cleaning unit 4 is replenished to the ink container 31 of the main body 1. In the solvent supply paths 809-810, when it is detected that the concentration of the ink 68A is high and the liquid level in the recovery container 73 is equal to or lower than the minimum liquid level detection portion 76B of the liquid level sensor 76, the solenoid valve (for solvent supply) 53 is energized to open the flow path, and the pump (for solvent) 37 is operated, so that the solvent 69A stored in the solvent container 33 is replenished to the ink container 31.

[0058] Next, Fig. 10 is a fluid path diagram showing the ink flow with a thick line when the inkjet recording apparatus 600 in this embodiment is in a state where the print head 2 is set in the head cleaning unit 4 and an ink circulation process is being performed. Even if the inkjet recording apparatus 600 is not used for a period of about one to two weeks, it is possible to reduce trouble at the start of operation the next time it is used by periodically circulating the ink (about once every two to three days). Therefore, in Fig. 10, a control for automatically circulating the ink 68A periodically will be described.

[0059] In the ink supply path (paths 801 to 803), when the solenoid valve (for supply) 49 is energized to open the flow path and operate the pump (for supply) 34, ink 68A contained in the ink container 31 of the main body 1 is supplied to the nozzle 21 of the print head 2 and ejected from the nozzle 21 as ink droplets 68B, as indicated by the thick arrow AA.

[0060] In the ink recovery path 804, the solenoid valve (for recovery) 50 is energized to open the flow path and the pump (for recovery) 35 is operated, whereby the ink particles 68B and the air around the print head 2 are sucked through the gutter 25 and sucked and pumped into the ink container 31 of the main body 1, as indicated by the bold line of the arrow BB. Then, the ink 68B that flows into the ink container 31 is contained at the bottom, and the air that has become a solvent gas is discharged to the outside of the main body 1 as the solvent gas, as indicated by the arrow T. Then, as indicated by the arrow DD, the concentration of the ink 68A is periodically measured by the viscosity measuring device 45, and the concentration (viscosity) of the ink 68A is controlled to be within a certain range.

[0061] With the ink circulation of this embodiment, even if a problem occurs that causes ink particles 68B ejected from the nozzles 21 to not enter the gutter 25, it is possible for the charge sensor 48 to detect this, and further, it is possible to prevent the ink 68B that has fallen out of the gutter 25 from soiling the surroundings of the inkjet recording apparatus 600. Even if the charge sensor 48 is unable to accurately detect that the ink particles 68B have not entered the gutter 25 due to a malfunction, the maximum liquid volume detection portion 76A of the liquid volume sensor 76 provided in the collection container 73 can detect the overflow of the ink 68B and stop the supply of the ink 68A to the nozzles 21.

[0062] Furthermore, in the inkjet recording apparatus 600, it is also possible to perform regular automatic head cleaning control in addition to regular automatic circulation control of the ink 68A. By doing so, it becomes possible to prevent troubles the next time the apparatus is used.

[0063] <Print head structure> Next, the specific configuration of the print head 2 of the inkjet recording device 600 according to the first embodiment will be described with reference to Fig. 11. Fig. 11 is a partial cross-sectional view showing the configuration of the print head in this embodiment. In Fig. 11, (a) shows the state in which the protective cover door 18 of the print head 2 is closed, and (b) shows the state in which the protective cover door 18 of the print head 2 is open.

[0064] 11(a), the print head 2 includes a head base 16, a conduit (for print head) 5 connecting the main body 1 and the print head 2, and a protective cover 17 that forms a print opening 17A through which ink particles 68B used for printing pass and is attached to the head base 16. The head base 16 is attached with a switching valve 26, a nozzle 21 connected to the switching valve 26 via a tube 803A, a charging electrode 23, a deflection electrode 24, and a gutter 25. The print head 2 is also attached with a temperature sensor A27 that detects the surrounding temperature and uses it for various controls. When the protective cover 17 is attached, the space surrounded by the head base 16 and the protective cover 17 is protected from impacts during maintenance, etc.

[0065] A cleaning opening 17B is formed in the protective cover 17, and the cleaning opening 17B can be opened and closed by a protective cover door 18 attached to the protective cover 17. The attachment position of the protective cover door 18 is determined by a pin 20 fixed to the protective cover 17, and the protective cover door 18 slides within the range of an elongated hole 18B formed in the protective cover door 18 in the direction of the arrow DC or in the direction opposite to the arrow DC (arrow DO).

[0066] The protective cover 17 forms a seat portion 17D, and a door closing spring 19 is attached to the seat portion 17D in a state in which a load is applied to the protective cover door 18 in the direction of the arrow DC. The door closing spring presses the rear surface of the opening / closing support portion 18A formed on the protective cover door 18 in the direction of the arrow DC, so that the protective cover door 18 covers the cleaning opening 17B. At this time, the protective cover door 18 comes to rest at a position where the opening lower end 17C formed on the protective cover 17 and the door lower end 18C formed on the protective cover door 18 come into contact with each other.

[0067] A magnet A29 is attached to the door bottom end 18C, and a proximity sensor A28 that detects when the magnet A29 approaches within a certain distance is attached to the protective cover door 18. When the protective cover door 18 covers the cleaning opening 17B, the proximity sensor A28 is in a non-detection state because the magnet A29 is away. Therefore, it can be determined that the protective cover 17 covers the cleaning opening 17B, and the nozzle 21, the charging electrode 23, and the deflection electrode 24 are in a protected state.

[0068] 11(b), the state in which the protective cover door 18 of the print head 2 is open will be described. The opening / closing support portion 18A of the protective cover door 18 is pressed in the direction of the arrow DO, and the door closing spring 19 is in a compressed state. The protective cover door 18 then comes to rest at a position where the door lower end portion 18C and the opening upper end portion 17E of the protective cover 17 come into contact with each other. The proximity sensor A28 attached to the protective cover 17 can detect that the distance to the magnet A29 attached to the protective cover door 18 is equal to or less than a certain distance.

[0069] 11, a sliding type protective cover door 18 is used so that the protective cover door 18 opens automatically when the print head is inserted into the cleaning tank 71, but the present invention is not limited to this. In other words, any type of door that can be opened during cleaning to facilitate cleaning of the structural components inside the print head (nozzle 21, charging electrode 23, deflection electrode 24, gutter 25, etc.) may be used, and for example, the protective cover may be formed with a door that can be opened and closed vertically or horizontally. Also, the protective cover itself may be made openable and closable.

[0070] <Head cleaning unit structure> Next, the configuration of the head cleaning unit 4 of the inkjet recording apparatus 600 according to the first embodiment will be described with reference to Fig. 12. Fig. 12 is a configuration diagram of the head cleaning unit 4 in the first embodiment (a cross-sectional view of the cleaning nozzle 74).

[0071] In Figure 12, the head cleaning unit 4 comprises a cleaning tank 71 in which the print head 2 is housed during head cleaning, a lid block 72 that is installed on top of the cleaning tank 71 and has a print head insertion portion 72A for setting the print head 2 in the head cleaning unit 4, and a recovery container 73 for storing the recovered solvent 69B used in the head cleaning process.

[0072] A lid member 83 is attached to the lid block 72 to prevent dust and other foreign matter from entering the cleaning tank 71 through the print head insertion portion 72A, which is an opening, when the print head 2 is not set in the print head insertion portion 72A. The lid member 83 is attached to the lid block 72 via a lid hinge 82. This lid member 83 forms a lid member protrusion 83A to reduce frictional resistance when the print head 2 is inserted into the head cleaning unit 4.

[0073] The lid block 72 is fitted with a cleaning nozzle 74 for spraying a head cleaning solvent 69A toward the print head 2, and an air nozzle 75 for blowing air to dry the print head 2 that has been wetted with the solvent 69A after head cleaning.

[0074] The cleaning nozzle 74 is formed with a liquid flow path section 74A formed inside the cleaning nozzle 74 so as to extend from the nozzle 21 in the direction of the gutter 25 when the print head 2 is set in the head cleaning unit 4, a liquid discharge hole A section 74B connected to the liquid flow path section 74A for spraying the solvent 69A so as to target the nozzle 21, a liquid discharge hole B section 74C connected to the liquid flow path section 74A for spraying the solvent 69A so as to target the deflection electrode 24, and a liquid discharge hole C section 74D connected to the liquid flow path section 74A for spraying the solvent 69A so as to target the surface on which the printing opening 17A of the protective cover 17 is formed. The liquid flow path section 74A formed in the cleaning nozzle 74 is adapted to be connected to a liquid flow path section 72B formed in the lid block 72.

[0075] The air nozzle 75 is formed with an air flow path section 75A formed inside the air nozzle 75 so as to extend from the nozzle 21 in the direction of the gutter 25 when the print head 2 is set in the head cleaning unit 4, an air discharge hole A section 75B connected to the air flow path section 75A for spraying air aimed at the space between the charging electrodes 23, and an air discharge hole B section 75C connected to the air flow path section 75A for spraying air aimed at the protective cover 17. Here, the air flow path section 75A formed in the air nozzle 75 is adapted to be connected to an air flow path formed in the lid block 72.

[0076] The head cleaning unit 4 is provided with a cleaning tank 71 below the lid block 72 for housing the print head 2 during head cleaning. The cleaning tank 71 is formed with a side wall portion 71A formed to prevent the solvent 69A ejected from the cleaning nozzle 74 from scattering around, and a liquid outlet portion 71D for causing the solvent 69A ejected from the cleaning nozzle 74 to flow out to the bottom of the cleaning tank 71. The cleaning tank 71 has a conical inner bottom portion 71C formed with an inclination so that the liquid outlet portion 71D is at its lowest position so that the solvent 69A can easily collect at the liquid outlet portion 71D. A temperature sensor B84 is attached inside the cleaning tank 71 to detect the ambient temperature of the head cleaning unit 4 and use it for various controls.

[0077] Furthermore, the head cleaning unit 4 is provided with a recovery container 73 at the bottom of the cleaning tank 71 for storing the solvent 69A used during head cleaning. The recovery container 73 stores the solvent 69A used during head cleaning that drips from the liquid outlet 71D of the cleaning tank 71 as recovered solvent 69B. The recovery container 73 has a liquid storage section 73A that holds the recovered solvent 69B, and the liquid storage section 73A is sealed by combining the upper part of the recovery container 73 with the lower part of the cleaning tank 71. The recovery container 73 also has a liquid level sensor 76 for detecting when the liquid level 69C of the recovered solvent 69B falls below a certain value and when the liquid level 69C rises above a certain value.

[0078] In the recovery container 73, a filter (for recovery container) 77 is attached to the lower part of the liquid storage part 73A in order to remove foreign matter that has been mixed into the recovered solvent 69B during head cleaning or the like. A liquid reservoir part 73B for storing the filtered recovered solvent 69B is formed in the lower part of the filter (for recovery container) 77. A solvent reuse flow path 73C connected to the liquid reservoir part 73B is formed in the recovery container 73, and the solvent reuse flow path 73C is connected to a tube 823A via a reuse joint 80. This tube 823A forms a part of the solvent reuse paths 823-824 and 807, and the recovered solvent 69B is supplied to the ink container 31 via the tube 823A.

[0079] The recovery container 73 is formed with a liquid discharge flow path 73D connected to the liquid reservoir 73B, and the liquid discharge flow path 73D is connected to a tube 86 made of a fluorine-based solvent-resistant material via a discharge joint A81. A discharge joint B87 is attached to the tube 86 by pressing an end of the tube 86 into an outlet portion on the opposite side to the discharge joint A81. A tube fixing portion 71G is formed in the cleaning tank 71, and the discharge joint B87 is fixed to the tube fixing portion 71G by a nut 89. A seal member 88 is attached to the tube fixing portion 71G. The seal member 88 seals the space between the discharge joint B87 and the cleaning tank 71 so that the solvent 69A does not flow out of the cleaning tank 71 and the recovery container 73.

[0080] In addition, a communication hole 71F is formed in the center of the tube fixing part 71G of the cleaning tank 71, and when the discharge joint B87 is fixed to the cleaning tank 71, the internal space of the cleaning tank 71 and the internal space of the tube 86 have the same pressure. Therefore, the internal space of the recovery container 73, which is connected to the cleaning tank 71 through the liquid outlet part 71D, and the internal space of the tube 86 have the same pressure. Therefore, the liquid level 69C of the recovered solvent 69B and the liquid level 69D of the tube 86 are at the same liquid level. As a result, even if the recovery container 73 is opaque, for example, the liquid amount in the recovery container 73 can be confirmed by checking the liquid level in the tube 86.

[0081] A liquid joint 78 connected to the liquid flow path section 72B is attached to the lid block 72, and a tube 822A is connected to the liquid joint 78 by a method such as press-fitting. This tube 822A forms a part of the head cleaning paths 809 and 821-822, and is connected to the solvent container 33 via the tube 822A. Furthermore, an air joint 79 connected to the air flow path section 72C is attached to the lid block 72, and a tube 825A is connected to the air joint 79 by a method such as press-fitting. This tube 825A forms a part of the 825... path (for dry air) 825, and is connected to the pump (for supplying dry air) 38 via the tube 825A.

[0082] The head cleaning unit 4 is covered with a cover 85 so that the tubes 822A, 823A, and 825A are not exposed to the outside of the head cleaning unit 4, and the cover 85 is fixed so as to sandwich the upper part of the lid block 72 and the lower part of the collection container 73. The conduit (for the head cleaning unit) 6 is attached to the lower part of the cover 85 so as not to protrude outside and interfere with other production equipment.

[0083] Next, the configuration when the print head 2 is set in the head cleaning unit 4 of the inkjet recording apparatus 600 according to the first embodiment will be described with reference to Figures 13 and 14. Figure 13 is a partial cross-sectional view of the head cleaning unit 4, showing the print head 2 set in the head cleaning unit 4 of the first embodiment. Figure 14 is an enlarged view of the print head 2 and cleaning nozzle 74 in Figure 13, and the configuration in the vicinity thereof.

[0084] 12 to 14, the print head 2 is set in the head cleaning unit 4. The lid member 83 of the head cleaning unit 4 is opened by inserting the print head 2 into the print head insertion part 72A. The print head 2 is in a state where it is pushed into a position where the nozzle 21, charging electrode 23, deflection electrode 24, and gutter 25 are inside the cleaning tank 71. The head cleaning unit 4 is prevented from shifting left and right or front and rear by fitting the inner wall surface of the hole of the print head insertion part 72A with the outer wall surface of the print head 2 so that the position of the print head 2 does not shift, and further, the head base 16 of the print head 2 comes to rest at a position where it abuts against the print head support part 71B formed in the cleaning tank 71, so that the position of the print head 2 when set in the head cleaning unit 4 is stable.

[0085] A sensor mounting portion 71E is formed in the cleaning tank 71, and a proximity sensor B90 is attached to the sensor mounting portion 71E. A magnet B30 is attached to the head base 16 of the print head 2, and when the distance between the magnet B30 and the proximity sensor B90 approaches a certain distance or less, the proximity sensor B90 can detect it. When the print head 2 is set in the head cleaning unit 4, the magnet B30 and the proximity sensor B90 approach each other to within a certain distance, so the proximity sensor B90 is detecting it, and it can be determined that the print head 2 is set in the head cleaning unit 4.

[0086] In addition, when the print head 2 is set in the head cleaning unit 4, the opening / closing support portion 18A of the protective cover door 18 abuts against the door support portion 72D formed on the lid block 72. In the print head 2, the weight of the print head 2 is greater than the spring force of the door closing spring 19, so the door closing spring 19 is compressed. The print head 2 moves downward until it abuts against the print head support portion 71B, but the position of the protective cover door 18 does not move below the door support portion 72D, so the cleaning opening 17B covered by the protective cover door 18 is opened. The proximity sensor A28 attached to the protective cover 17 detects that the distance to the magnet A29 attached to the protective cover door 18 is equal to or less than a certain distance, so it can be determined that the print head 2 is set in the head cleaning unit 4.

[0087] <How to use the head cleaning unit> Next, the operation of the inkjet recording apparatus 600 according to the first embodiment when the print head 2 is set in the head cleaning unit 4 and a head cleaning process is being performed will be described with reference to Fig. 15. Fig. 15 is a cross-sectional view of the head cleaning unit 4 showing the flow of liquid inside the head cleaning unit 4 when the head cleaning process of the first embodiment is being performed.

[0088] 15, the inkjet recording device 600 performs a head cleaning process by ejecting a solvent 69A from a cleaning nozzle 74 to clean the print head 2. The solvent 69A supplied to the cleaning nozzle 74 is ejected as the solvent 69A in the directions indicated by the arrow EE (the direction in which the solvent 69A is ejected from the liquid ejection hole A portion 74B toward the nozzle 21) and the arrow FF (the direction in which the solvent 69A is ejected from the liquid ejection hole B portion 74C toward the deflection electrode 24), and the solvent 69A enters the inside of the protective cover 17 from the cleaning opening 17B, and is sprayed onto components such as the nozzle 21 and the deflection electrode 24 assembled to the print head 2, thereby cleaning away stains caused by the ink 68A that have adhered during operation or maintenance of the inkjet recording device 600.

[0089] The solvent 69A sprayed onto components such as the nozzle 21 and deflection electrode 24 assembled to the print head 2 drips and flows due to gravity in the direction indicated by the arrow HH, and when the print head 2 is set in the head cleaning unit 4, the solvent 69A can clean the charging electrode 23 and the gutter 25 located below the deflection electrode 24. The solvent 69A supplied to the cleaning nozzle 74 is sprayed in the direction indicated by the arrow GG (the direction in which the solvent 69A is sprayed from the liquid discharge hole C portion 74D toward the surface of the protective cover 17 on which the printing opening 17A is formed), and the solvent 69A can be sprayed onto the protective cover 17 to clean stains caused by the ink 68A adhering to the outside of the print head 2.

[0090] During the head cleaning process, the solvent 69A, which has been used to clean components arranged on the print head 2 such as the nozzle 21, charging electrode 23, deflection electrode 24, gutter 25, and protective cover 17, drips down in the directions indicated by arrows JJ and KK and flows into a recovery container 73 installed at the bottom of the head cleaning unit 4, and is stored in the liquid storage section 73A as recovered solvent 69B.

[0091] Next, the liquid level detection of the collection container 73 in each state of the inkjet recording apparatus 600 according to the first embodiment will be described with reference to FIG. 16. FIG. 16 is a cross-sectional view mainly showing the collection container 73 of the head cleaning unit 4 in this embodiment. In FIG. 16, (a) shows a state in which the liquid level sensor 76 of the collection container 73 detects neither the maximum liquid level detection portion 76A nor the minimum liquid level detection portion 76B. (b) of FIG. 16 shows a state in which the liquid level sensor 76 detects the maximum liquid level detection portion 76A because the liquid level of the collected solvent 69B in the collection container 73 is high. And (c) of FIG. 16 shows a state in which the liquid level sensor 76 detects the minimum liquid level detection portion 76B because the liquid level of the collected solvent 69B in the collection container 73 is low.

[0092] In FIG. 16(a), the liquid level sensor 76 installed inside the recovery container 73 includes a float portion 76C that displaces up and down together with the liquid level 69C of the recovered solvent 69B, a maximum liquid level detection portion 76A that is installed below the liquid outlet portion 71D of the cleaning tank 71 and detects when the float portion 76C approaches, and a minimum liquid level detection portion 76B that is installed below the maximum liquid level detection portion 76A and above the filter (for recovery container) 77 and detects when the float portion 76C approaches. The float portion 76C is in a state where neither the maximum liquid level detection portion 76A nor the minimum liquid level detection portion 76B is detecting it. In this state, the recovered solvent 69B stored in the recovery container 73 can be normally replenished to the ink container 31. In addition, the inkjet recording device 600 can perform a head cleaning process by setting the print head 2 in the head cleaning unit 4 and spraying the solvent 69A from the cleaning nozzle 74.

[0093] 11(b), a state will be described in which the liquid level sensor 76 detects the maximum liquid level detection portion 76A because the amount of recovered solvent 69B in the recovery container 73 is large. In the recovery container 73, the amount of recovered solvent 69B increases due to repeated head cleaning processes, and the liquid level C becomes high. The liquid level sensor 76 can determine that the amount of recovered solvent 69B is large because the float portion 76C, which displaces in conjunction with the liquid level 69C, and the maximum liquid level detection portion 76A are approaching a certain distance or less. When this state is detected, the inkjet recording device 600 controls the cleaning nozzle 74 so as not to spray the solvent 69A in order to prevent the recovered solvent 69B from overflowing from the recovery container 73.

[0094] Next, in FIG. 11(c), a state will be described in which the liquid level sensor 76 detects the minimum liquid level detection portion 76B because the liquid level of the recovered solvent 69B in the recovery container 73 is low. In the recovery container 73, the head cleaning process has not been performed for a certain period of time, so the amount of recovered solvent 69B is low and the liquid level 69C is low. The liquid level sensor 76 can determine that the liquid level of the recovered solvent 69B is low because the float portion 76C, which displaces in conjunction with the liquid level, and the minimum liquid level detection portion 76B are approaching a certain distance or less. When this state is detected, the inkjet recording device 600 controls the ink container 31 to be replenished with solvent 69A from the solvent container 33, and adjusts the solvent concentration of the ink 68A, because the recovered solvent 69B contained in the recovery container 73 cannot be normally replenished to the ink container 31.

[0095] Next, the liquid draining operation of the recovery container 73 of the inkjet recording device 600 according to the first embodiment will be described with reference to FIG. 17. FIG. 17 is a cross-sectional view of the head cleaning unit 4 when the liquid draining operation of the recovery container 73 is being performed. In the inkjet recording device 600, when the amount of recovered solvent 69B in the recovery container 73 increases and the liquid volume sensor 76 detects the maximum liquid volume detection portion 76A, the head cleaning process cannot be performed. In that case, when the head cleaning process is performed, it is necessary to reduce the amount of recovered solvent 69B in the recovery container 73 so that the maximum liquid volume detection portion 76A is not detected. One method for this is to replenish the recovered solvent 69B in the recovery container 73 to the ink container 31, but it may take time for the amount of recovered solvent 69B to decrease. Another method is to drain the recovered solvent 69B from the recovery container 73.

[0096] 17, the discharge joint B87 is detached from the tube fixing part 71G of the cleaning tank 71, and the tube 86 is arranged so that the discharge joint B87 is lower than the recovery container 73. This allows the recovered solvent 69B contained in the recovery container 73 to flow out of the head cleaning unit 4.

[0097] <Effects of Example 1> As described above, according to the first embodiment of the present invention, the print head can be easily cleaned by simply setting (inserting) the head cleaning unit, and furthermore, the solvent 69A used in head cleaning can be collected and stored in the recovery container 73. In addition, the recovered solvent 69B can be reused to adjust the concentration of the ink 68A stored in the ink container 31. Therefore, according to the inkjet recording device 600, it is possible to provide an inkjet recording device 600 that reduces the effort of disposing of the recovered solvent 69B during the head cleaning operation and reduces the amount of recovered solvent 69B disposed, thereby enabling a reduction in the running costs of the customer.

[0098] Example 2 An inkjet recording apparatus 700 according to a second embodiment of the present invention will be described with reference to Figures 18 and 19. Note that a description of parts common to the first embodiment will be omitted, and the following mainly describes parts different from the first embodiment.

[0099] <Appearance> Fig. 18 is an external perspective view showing inkjet recording apparatus 700 in this embodiment, with a portion cut away so as to show the inside of main body 1. Fig. 19 is a perspective view showing the state in which print head 2 is attached to cleaning tank 271 in inkjet recording apparatus 700 in this embodiment.

[0100] First, as shown in FIG. 18(a), the inkjet recording device 700 includes a main body 201 and a print head 2 connected to the main body 1 by a conduit (for print head) 5. The main body 201 includes a maintenance door 9 on the front side, and inside the maintenance door 9, a container base 95 is attached to the lower part, and circulation system parts such as an auxiliary ink container 32, a solvent container 33, a head cleaning unit 204, and a drive unit 203 are attached on the container base 95. A maintenance door handle 94 is attached to the upper center part of the maintenance door 9, so that an operator can easily open and close the maintenance door 9. By opening the maintenance door 9, the inkjet recording device 700 can perform daily maintenance work such as refilling the auxiliary ink container 32 with ink 68A, refilling the solvent container 33 with solvent 39A, and cleaning the print head 2 with solvent 69A using the head cleaning unit 204.

[0101] The inkjet recording apparatus 700 shown in Fig. 18(b) is in a state where the maintenance door 9 is open and the head cleaning unit 204 is pulled out towards the front. The maintenance door 9 can be opened up to an angle of 90°, and a rail 296 is formed on the rear surface of the maintenance door 9. The head cleaning unit 204 can be pulled out towards the front on the rail 296. The head cleaning unit 204 is configured as one unit with the drive unit 203 for the purpose of simplifying the components.

[0102] 19, the state in which the print head 2 is set in the head cleaning unit 204 in the inkjet recording device 700 will be described. The print head 2 is inserted into the print head insertion section 72A of the head cleaning unit 204, starting from the tip of the print head 2. By setting the print head 2 in the head cleaning unit 204 in this way, the inkjet recording device 700 in this embodiment is able to clean the print head 2.

[0103] <Route configuration> 20 is a diagram showing the overall path configuration of an inkjet recording apparatus 700 in this embodiment. Note that a description of parts common to embodiment 1 will be omitted, and the following mainly describes parts that are different from embodiment 1.

[0104] Head cleaning paths 809, 821, and 841 of the inkjet recording apparatus 700 in this embodiment will be described. In Fig. 20, the pump (for solvent) 37 is connected to the path 821 via a branch path 903, and the path 821 is connected to a path 841 via a connection part (for head cleaning) 59A and a joint (for head cleaning) 260A for relaying with the driving part 203 incorporated inside the main body 201. A solenoid valve (for nozzle cleaning) 55 for opening and closing the flow path is disposed in the path 841, and the solenoid valve (for nozzle cleaning) 55 is connected to a filter (for head cleaning) 42 for removing foreign matter mixed in the solvent 69A.

[0105] The filter (for head cleaning) 42 is connected to a filter (for cleaning nozzle) 43 in order to remove foreign matter that may initially get mixed into the path 841. The filter (for cleaning nozzle) 43 is connected to a cleaning nozzle 74 provided inside a cleaning tank 71 of the head cleaning unit 204. Here, the space inside the cleaning tank 71 is configured to communicate with a collection container 73 installed below.

[0106] Next, the solvent reuse paths 842, 824, and 807 of the inkjet recording apparatus 700 in this embodiment will be described. In Fig. 20, the head cleaning unit 204 is provided with a recovery container 73 for holding the recovered solvent 69B that flows in under its own weight after being used for head cleaning, and a filter (for recovery container) 77 is attached to the recovery container 73 so that foreign matter mixed in during head cleaning does not flow into the path 842. The recovery container 73 is connected to the path 842 at a portion immersed in the recovered solvent 69B, and the path 842 is provided with a filter (solvent reuse) 44 in the drive unit 203 inside the main body 201 to prevent fine foreign matter contained in the recovered solvent 69B from mixing with the ink 68A.

[0107] The filter (solvent reuse) 44 is connected to an electromagnetic valve (solvent reuse) 57 for opening and closing the flow path, and a path 842 in which the electromagnetic valve (solvent reuse) 57 is arranged is connected to a path 824 via a connection part (solvent reuse) 59B for relaying with the drive unit 203 and a joint (solvent reuse) 260B. The path 824 is connected to a pump (for circulation) 36 arranged in a path 807 via a junction path 902. This makes it possible for the recovered solvent 69B held in the recovery container 73 to be replenished to the ink container 31, and is configured so that it can be reused for adjusting the ink concentration.

[0108] Next, a head dry air path 843 of the inkjet recording apparatus 700 in this embodiment will be described. In Fig. 20, the driving unit 203 housed in the main body 201 is provided with a pump (for supplying dry air) 38 used to suck and pressurize air, and the pump (for supplying dry air) 38 forms an air suction port communicating with the inside of the main body 201. The pump (for supplying dry air) 38 is connected to an air nozzle 75 provided in the cleaning tank 71 of the head cleaning unit 204.

[0109] <Effects of Example 2> As described above, according to the second embodiment of the present invention, the inkjet recording apparatus 700 has the cleaning tank 271 and the recovery container 273 disposed inside the main body 201, and thus it is possible to provide an inkjet recording apparatus 700 that is equipped with a head cleaning function and a function for reusing the recovered solvent 69B, similar to the first embodiment, and has improved ease of installation.

[0110] Other Examples Although the first and second embodiments have been described above, the present invention is not limited to the first embodiment, but includes various modified examples. Also, the first and second embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all of the configurations described. [Explanation of symbols]

[0111] 1...main body, 2...print head, 3...drive unit, 4...head cleaning unit, 5...conduit, 6...conduit, 8...operation display unit, 9...maintenance door, 10...control unit, 11...belt conveyor, 12A...printing object (before printing), 12B...printing object (after printing), 13...print head fixing bracket, 14...conveyor pillar, 16...head base, 17...protective cover, 17A...printing opening, 17B...cleaning opening, 17C...opening lower end, 17D...seat portion, 17E...opening upper end, 18...protective cover door, 18A...opening / closing support portion, 18B...long hole portion, 18C...door lower end, 18D...door upper end, 19...door closing bar , 20...pin, 21...nozzle, 21A...outlet, 23...charged electrode, 24...deflection electrode, 25...gutter, 25A...gutter outlet, 26...switching valve, 27...temperature sensor A, 28...proximity sensor A, 29...magnet A, 30...magnet B, 31...ink container, 31A...liquid level sensor, 32...auxiliary ink container, 33...solvent container, 34...pump (for supply), 35...pump (for recovery), 36...pump (for circulation), 37...pump (for solvent), 38...pump (for dry air supply), 39...filter (for supply), 40...filter (for recovery), 41...filter (for nozzle cleaning), 42...filter filter (for head cleaning), 43...filter (for cleaning nozzle), 44...filter (for reusing solvent), 45...viscosity measuring device, 46...pressure adjusting valve, 47...pressure sensor, 48...charge sensor (detection means), 49...solenoid valve (for supply), 50...solenoid valve (for recovery), 51...solenoid valve (for circulation), 52...solenoid valve (for measuring viscosity), 53...solenoid valve (for replenishing solvent), 54...solenoid valve (for replenishing ink), 55...solenoid valve (for cleaning nozzle), 56...solenoid valve (for cleaning head), 57...solenoid valve (for reusing solvent), 58...storage area, 59A...connection (for cleaning head), 59B...connection (for reusing solvent), 60A...connection hand (for head cleaning), 60B...joint (for reusing solvent), 61A...sealing plug (for supplying solvent), 61B...sealing plug (for reusing solvent), 63...start button, 64...stop button, 65...display section, 68A...ink, 68B...ink particles, 69A...solvent, 69B...recovered solvent, 69C...liquid level, 69D...liquid level, 71...cleaning tank, 71A...side wall, 71B...print head support section, 71C...conical inner bottom, 71D...liquid outlet, 71E...sensor mounting section, 71F...communicating hole section, 71G...tube fixing section, 72...lid block, 72A...print head insertion section, 72B...liquid flow path section, 72C...air flow path section,72D...door support portion, 73...recovery container, 73A...liquid storage portion, 73B...liquid pool portion, 73C...solvent reuse flow path, 73D...liquid discharge flow path, 74...cleaning nozzle, 74A...liquid flow path portion, 74B...liquid discharge hole A portion, 74C...liquid discharge hole B portion, 74D...liquid discharge hole C portion, 75...air nozzle, 75A...air flow path portion, 75B...air discharge hole A portion, 75C...air discharge hole B portion, 76...liquid level sensor, 76A...maximum liquid level detection portion, 76B...minimum liquid level detection portion, 76C...float part, 77...filter (for collection container), 78...liquid joint, 79...air joint, 80...recycling joint, 81...discharge joint A, 82...lid hinge, 83...lid member, 83A...lid member protrusion, 84...temperature sensor B, 85...cover, 86...tube, 87...discharge joint B, 88...sealing member, 89...nut, 90...proximity sensor B, 91...fixing jig (for main body), 92...fixing jig (for conveyor), 93...fixing jig fitting part, 94...maintenance door handle, 201...main Body, 203... drive unit, 204... head cleaning unit, 260A... joint (for head cleaning), 260B... joint (for reusing solvent), 271... cleaning tank, 273... collection container, 295... container base, 296... rail, 600... inkjet recording device, 700... inkjet recording device, 801 to 803... path (for supply), 804... path (for recovery), 805... path (for exhaust), 806 to 807... path (for circulation), 808... path (for viscosity measurement), 8 09...route (for solvent supply), 810...route (for solvent refill), 811...route (for ink refill), 812...route (for nozzle cleaning), 821~822...route (for head cleaning), 823~824...route (for solvent reuse), 825...route (for dry air), 841...route (for head cleaning), 842...route (for solvent reuse), 843...route (for dry air), 901...junction route (for supply), 902...junction route (for circulation), 903...branch route (for solvent),

Claims

1. An inkjet recording device having a main body and a print head, the main body portion includes an ink container that contains ink for printing on a print target and supplies ink to the print head portion, and a solvent container that contains a solvent and supplies the solvent to the print head portion; the print head unit has a nozzle connected to the ink container and ejecting pressurized ink, a charging electrode for charging ink droplets ejected from the nozzle, a deflection electrode for deflecting the ink droplets charged by the charging electrode, and a gutter for collecting ink not used for printing; The printer further includes a head mounting unit configured to be able to mount the print head unit, The head mounting unit is an inkjet recording device having a head detection section that uses magnetic force to detect whether the print head section is mounted.

2. 2. The inkjet recording apparatus according to claim 1, the head mounting unit is used when cleaning the print head with a solvent, and has a bottom portion formed with a communication hole through which a cleaning liquid passes, and a peripheral wall portion extending upward from the bottom portion; an ink jet recording apparatus having a structure in which, when the print head is attached, a tip portion of the print head is surrounded by the peripheral wall portion.

3. 3. The inkjet recording apparatus according to claim 1, The inkjet recording apparatus is characterized in that the head mounting unit has a structure that allows it to be detachably attached to a side wall of the main body.

4. The inkjet recording apparatus according to any one of claims 1 to 3, The head mounting unit is used to clean the print head unit with a solvent when the print head unit is mounted, and is characterized in that the inkjet recording apparatus further comprises a recovery container for recovering the cleaning liquid used to clean the print head unit.

5. 5. The inkjet recording apparatus according to claim 4, The inkjet recording apparatus further comprises a head cleaning unit for performing periodic automatic head cleaning control.

6. 6. The inkjet recording apparatus according to claim 4, An ink jet recording apparatus, characterized in that, when the print head is attached to the head cleaning unit, ink is ejected to perform ink circulation.

7. An inkjet recording device having a main body and a print head, The main body portion has an ink container that contains ink for printing on a print target, and a solvent container that contains a solvent, the print head unit has a nozzle connected to the ink container and ejecting pressurized ink, a charging electrode for charging ink droplets ejected from the nozzle, a deflection electrode for deflecting the ink droplets charged by the charging electrode, and a gutter for collecting ink not used for printing; The printer further includes a head mounting unit configured to be able to mount the print head unit, The head mounting unit of the inkjet recording apparatus includes a recovery container that recovers cleaning liquid used to clean the print head, and a liquid volume sensor that detects the amount of cleaning liquid accumulated in the recovery container.

8. 8. The inkjet recording apparatus according to claim 7, The ink jet recording apparatus according to claim 1, wherein the head cleaning unit has a head detection means for detecting whether the print head is installed.

9. 9. The inkjet recording apparatus according to claim 8, The ink jet recording apparatus according to claim 1, wherein the head detection means detects whether the print head is attached by utilizing a magnetic force.

10. The inkjet recording apparatus according to any one of claims 7 to 9, The inkjet recording apparatus further comprises a head cleaning unit for performing periodic automatic head cleaning control.

11. The inkjet recording apparatus according to any one of claims 7 to 10, An ink jet recording apparatus, characterized in that, when the print head is attached to the head cleaning unit, ink is ejected to perform ink circulation.

12. 12. The inkjet recording apparatus according to claim 10, An ink jet recording apparatus characterized in that, when the ink or cleaning liquid in the recovery container exceeds a certain value by the overflow detection, control is performed so as to stop ink ejection or head cleaning.

13. The inkjet recording apparatus according to any one of claims 7 to 12, The head mounting unit has a bottom portion having a communication hole for passing a cleaning liquid therethrough, and a peripheral wall portion extending upward from the bottom portion, an ink jet recording apparatus having a structure in which, when the print head is attached, a tip portion of the print head is surrounded by the peripheral wall portion.

14. The inkjet recording apparatus according to any one of claims 7 to 13, An inkjet recording apparatus, characterized in that control is performed so that solvent gas during cleaning of said print head portion is sucked from at least one of said gutter and a nozzle of said print head portion.

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