Inkjet recording apparatus

Abstract

To provide an ink jet recorder in which a print head can be cleaned easily and a solvent (cleaning liquid) used for cleaning can be recovered easily.SOLUTION: The ink jet recording apparatus having a printing head receiving the supply of ink to perform printing and a main body including an ink container for housing ink and a solvent container for housing a solvent to supply the ink in the ink container to the printing head is equipped with a washing tank, a washing nozzle and a recovery container. The print head is set in the cleaning tank, the solvent is ejected from the cleaning nozzle to clean the print head, and the solvent after cleaning 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 print on a print-receiving medium. [Background technology]

[0002] A technique related to nozzle cleaning in this technical field is known, as described in Japanese Patent Laid-Open No. 2002-103636 (Patent Document 1). Patent Document 1 states, "A fixed cleaning jet is installed in the print head downstream of the ink nozzle to be cleaned, 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 expelled 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 causing the ink residue to adhere to the side of the housing."

[0003] Another known technique related to nozzle cleaning is described in Japanese Patent Laid-Open No. 2015-136934 (Patent Document 2). Patent Document 2 states, "A cleaning nozzle, i.e., an ASC nozzle, is provided for cleaning the nozzles 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 arranged inside the head so as to face the nozzle outlet. This ASC nozzle (cleaning nozzle) is connected to the solvent line and solvent tank via an openable / closable air valve. When cleaning the nozzle, the openable / closable air 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] Japanese Patent Application Laid-Open No. 2002-103636 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-136934 Summary of the Invention [Problem to be solved by the invention]

[0005] In the technology of Patent Document 1, ink residue adhering to the nozzles inside the print head adheres to a part other than the nozzles (the side of the print head housing) when the print head is cleaned. This requires a separate manual cleaning of that part with a solvent, which is a cumbersome process. 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 does not describe 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 the 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 that receives a supply of ink and performs printing, and a main body that includes an ink container for storing ink and a solvent container for storing a solvent, and supplies the ink in the ink container to the print head, the print head being equipped with a nozzle that converts the ink into ink droplets and ejects them, a charging electrode that charges the ink droplets ejected from the nozzle in accordance with the content to be printed, a deflection electrode that changes the direction of flight of the charged ink droplets, and a gutter that collects the ink droplets that do not contribute to the printing, and the inkjet recording apparatus is also equipped with a cleaning tank for setting the print head, a cleaning nozzle that sprays the solvent towards the print head set in the cleaning tank to clean it, and a head cleaning unit that includes a recovery container located at the bottom of the cleaning tank and for recovering the solvent after cleaning, and a drive unit that 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 that receives a supply of ink to perform printing, and a main body that includes an ink container for storing ink and a solvent container for storing solvent, and supplies the ink in the ink container to the print head, wherein the print head is set inside a cleaning tank that is equipped with a cleaning nozzle that sprays the solvent, and then the solvent is sprayed from the cleaning nozzle to clean the print head, and the solvent after cleaning is recovered in a recovery container provided at the bottom of the cleaning tank. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an inkjet recording device and a method for controlling 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 explanation of the drawings]

[0011] [Figure 1]1 is a perspective view showing a usage state of an inkjet recording apparatus according to a first embodiment of the present invention. [Figure 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. [Figure 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 according to the first embodiment. [Figure 5] FIG. 3 is a diagram showing the path configuration of the inkjet recording apparatus in a state where a head cleaning unit is removed in the first embodiment. [Figure 6] FIG. 3 is a diagram showing the path configuration of the head cleaning unit in a state where it is removed from the inkjet recording apparatus main body in the first embodiment. [Figure 7] 10 is a fluid path diagram showing the flow of liquid by a thick line when a head cleaning process is performed in the first embodiment. FIG. [Figure 8] 10 is a fluid path diagram showing the air flow indicated by a thick line when a head drying process is performed in Example 1. FIG. [Figure 9] 1 is a fluid path diagram showing the flow of ink and solvent by bold lines when the ink and solvent are being replenished in Example 1. 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] 3 is a cross-sectional view of the head cleaning unit in the first embodiment with the print head set in the head cleaning unit. FIG. [Figure 14] FIG. 14 is an enlarged view of the print head and its surroundings in FIG. 13. [Figure 15] 4 is a cross-sectional view of the head cleaning unit, in which the thick lines indicate 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] 10 is a cross-sectional view of the head cleaning unit when the liquid is being drained from the collection container in the first embodiment. FIG. [Figure 18] FIG. 10 is a perspective view showing the appearance of an inkjet recording apparatus according to a second embodiment of the present invention. [Figure 19] FIG. 10 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. 10 is a diagram showing a path configuration of an inkjet recording apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[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 the following drawings, the same devices are given the same numbers (reference symbols), 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 Figures 1 to 3. Figure 1 is a perspective view showing the usage state of the inkjet recording apparatus 600 in this embodiment, and Figure 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. Figure 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, the inkjet recording device 600 according to this embodiment comprises 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 foods, beverages, etc. are produced, and main body 1 is installed in a location where there is enough space for periodic maintenance work, etc. Print head 2 is fixed to print head fixing bracket 13 installed near belt conveyor 11, and is 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 to protect the internal components of print head 2.

[0016] In this inkjet recording device 600, a control unit 10 (specific configuration not shown) installed inside the main body 1 controls the amount and timing of charging of ink droplets 68B ejected from nozzles 21 attached to the print head 2. That is, the control unit 10 controls the ink droplets 68B to adhere to the print target (before printing) 12B, which are charged and deflected while the print target (before printing) 12A passes near the print head 2, thereby performing printing. The control unit 10 also controls solenoid valves, pumps, and other devices installed inside the main body 1 to control the flow of ink and solvent. The control unit 10 can also use a computer. Specifically, the control unit 10 can be composed of a microprocessing unit (MPU), a memory for storing programs for operating the MPU and data and information required for operation, and a print driver that operates the print head and other components within the main body 1 in response to instructions from the MPU. Details of the control unit 10 are omitted here.

[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 A (for conveyor) 92 attached to the belt conveyor 11 with a fixing jig fitting portion 93 attached to the head cleaning unit 4. 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 displaying confirmation messages and alarms such as warnings and abnormalities to the operator.

[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 apparatus 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] Next, with reference to Figure 2, we will explain the state in which the print head 2 is set in the head cleaning unit 4 of the inkjet recording device 600. 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 via the conduit 6.

[0021] It is preferable that the length of the conduit (for the head cleaning unit) 6 connecting the main body 1 and the head cleaning unit 4 is 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 a degree of freedom in the placement of the head cleaning unit 4.

[0022] Next, a state in which the head cleaning unit 4 is fixed to the main body 1 of the inkjet recording apparatus 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 it 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 the 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 a solenoid valve (for supply) 49 that opens and closes the path is installed midway along the path 801. Furthermore, the path 801 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 pressure-feed 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] Filter (for supply) 39 is connected to pressure regulating valve 46, which adjusts the pressure of ink 68A pumped from pump (for supply) 34 to an appropriate pressure for printing, and pressure regulating valve 46 is connected to pressure sensor 47, which measures the pressure of ink 68A supplied to nozzles 21. Path 802, in which pressure sensor 47 is located, passes through conduit (for print head) 5 and is connected to switching valve 26, which is provided inside print head 2 and controls whether ink 68A is supplied to nozzles 21.

[0027] The switching valve 26 is connected via a path 803 to a nozzle 21 having an ejection port 21A that ejects 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, allowing the supply of ink 68A and solvent 69A to be switched to the nozzle 21. In the straight direction of the ejection port 21A of the nozzle 21, there are arranged a charging electrode 23 for adding a predetermined amount of charge to the ink droplets 68B, a deflection electrode 24 for deflecting the ink droplets 68B to be used for printing, and a gutter 25 for capturing the ink droplets 68B that are not used for printing and therefore fly straight without being charged or deflected.

[0028] Next, an ink recovery path 804 of the inkjet recording apparatus 600 of 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 to detect 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 the print head) 5 and is connected to a filter (for recovery) 40 disposed in the main body 1 that removes foreign matter mixed in with the ink, and the filter (for recovery) 40 is connected to a solenoid 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 into the ink container 31. The ink container 31 is also connected to a path 805 in an upper space that does not come into contact with 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 apparatus 600 in this embodiment will be described. In addition to the path 803 for ink supply, the nozzles 21 provided in the print head 2 are connected to a path 806 that passes through a conduit (for the print head) 5. A solenoid valve (for circulation) 51 provided in the main body 1 for opening and closing the flow path is arranged in this path 806.

[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 connected to an ink container 31.

[0032] Next, the viscosity measurement paths (paths 808 and 807) of the inkjet recording apparatus 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. Path 808 is connected to a viscosity measuring device 45 via a path 801 to measure the viscosity of the ink 68A in the ink container 31. The viscosity measuring device 45 is connected to a solenoid valve (for viscosity measurement) 52 that opens and closes the path. The solenoid valve (for viscosity measurement) 52 is connected to a pump (for circulation) 36 disposed 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, thereby measuring the viscosity of the ink 68A. The viscosity measured in this manner 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 paths (paths 809-810) of the inkjet recording apparatus 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 used for supplying solvent to the ink container 31, for nozzle cleaning, or for head cleaning. 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 connected to the ink container 31.

[0034] Next, the ink supply path 811 of the inkjet recording apparatus 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 a solenoid valve (for ink supply) 54 that opens and closes the path, and the solenoid 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 pressure-feed the ink 68C. The ink 68C in the auxiliary ink container 32 passes through the nozzle 21, the gutter 25, the path 804, the solenoid valve 50, and the pump 35, before being refilled into the ink container 31.

[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 arranged in path 809 is connected to path 812 via a branch path 903. Path 812 is connected to a solenoid valve (for nozzle cleaning) 55 for opening and closing the flow path. The solenoid valve (for nozzle cleaning) 55 is then 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 path 812 that passes through the conduit (for print head) 5, and is connected to a switching valve 26 for controlling whether or not the cleaning solvent 69A is sent to the nozzles 21.

[0036] Next, the head cleaning paths (path 809, paths 821 and 822) of the inkjet recording apparatus 600 in this embodiment will be described. In Fig. 4, the pump (for solvent) 37 is connected to path 821 via a branch path 903, and path 821 is connected to path 822 via a connector (for head cleaning) 59A and a joint (for head cleaning) 60A for relaying with the drive unit 3 incorporated inside the main body 1. A solenoid valve (for nozzle cleaning) 56 for opening and closing the flow path is disposed in path 822, and the solenoid 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 that passes 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 paths (paths 823-824 and path 807) of the inkjet recording apparatus 600 in this embodiment will be described. In FIG. 4, the head cleaning unit 4 is provided with a recovery container 73 that holds post-head-cleaning recovered solvent 69B, which flows in under its own weight after being used for head cleaning. A filter (for the recovery container) 77 is attached to the recovery container 73 to prevent foreign matter mixed in during head cleaning from flowing 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 the 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 intended to prevent fine foreign matter contained in the recovered solvent 69B from mixing into the ink 68A.

[0039] Furthermore, the output side of the filter (solvent reuse) 44 is connected to a solenoid valve (solvent reuse) 57 for opening and closing the flow path via 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 a pump (for circulation) 36 arranged in the path 807 via a junction path 902. This allows 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 reaches or exceeds a predetermined value, the control unit 10 supplies the solvent 69B used to clean 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 pressurize air, and the pump (for supplying dry air) 38 forms an air suction port that communicates with the inside of the main body 1. The pump (for supplying dry air) 38 is connected to an air nozzle 75 provided inside the cleaning tank 71 of the head cleaning unit 4 via a path 825 that passes through the conduit (for the 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 diagram showing the path configuration of the inkjet recording apparatus 600 in this embodiment when the head cleaning unit 4 is incorporated. Fig. 5 is a diagram showing the path configuration of the inkjet recording apparatus 600 in this embodiment when the head cleaning unit 4 is not incorporated. Fig. 6 is a diagram showing the path configuration 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. A sealing plug 61A is attached to a connection part (for head cleaning) 59A of a path 821 connected to the cleaning nozzle 74 of the head cleaning unit 4 in order to close the flow path. Furthermore, a sealing plug 61B is attached to a connection part (for solvent reuse) 59B of a path 824 connected to the collection container 73 of the head cleaning unit 4 in order to close the flow path. Furthermore, 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 the head cleaning unit) 6. The drive unit 3 incorporates a pump (for supplying dry air) 38, a solenoid valve (for head cleaning) 56, a solenoid 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 apparatus 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, 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 the flow of solvent and the flow of air by bold lines 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 enabling the solvent to be supplied to the head cleaning unit 4, as indicated by the bold arrow A. In other words, the solvent 69A stored 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 this solvent 69A toward the print head to clean it. Specifically, part of the solvent 69A supplied to the cleaning nozzle 74 is discharged toward the nozzles 21, which are enclosed by the protective cover 17 of the print head 2, as indicated by the bold line of arrow B, and the other part is discharged toward the protective cover 17 on the outside of the print head 2, as indicated by the bold line of arrow C. The solvent 69A discharged from the cleaning nozzle 74, as indicated by the bold line of arrow B, cleans components assembled inside the print head 2, such as the nozzles 21, charging electrode 23, deflection electrode 24, and gutter 25, and then drips downward by gravity, as indicated by the bold line of arrow E. The solvent 69A that drips to the bottom of the cleaning tank 71 flows toward the recovery container 73, as indicated by the bold line of arrow F, and is collected inside the recovery container 73 as recovered solvent 69B.

[0048] In the ink circulation paths (paths 806-807), the electromagnetic valve (for circulation) 51 is energized to open the flow path and operate the pump (for circulation) 36, whereby part of the solvent 69A that hits the nozzles 21A is sucked from the nozzles 21A as shown by the thick arrow G and collected in the ink container 31 of the main body 1. In this way, in the head cleaning process, the inside of the nozzles 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 part of the solvent 69A that hits the gutter 25 is sucked out of the gutter 25 as shown by the thick arrow H and recovered in the ink container 31 of the main body 1. 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, Figure 8 is a fluid path diagram showing the air flow with thick lines when a head drying process is being performed in the inkjet recording apparatus 600 of this embodiment. In Figure 8, the inkjet recording apparatus 600 has the print head 2 set in the head cleaning unit 4, and is designed 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 installed in the cleaning tank 71 of the head cleaning unit 4 by operating the pump (for supplying dry air) 38 installed in the main body 1, as shown by the thick line arrow J.

[0051] Some of the air supplied to the air nozzle 75 is discharged toward the charging electrode 23 enclosed by the protective cover 17 of the print head 2, as indicated by the thick line with arrow K, and the other portion is discharged toward the protective cover 17 on the outside of the print head 2, as indicated by the thick line with arrow L. The air discharged from the air nozzle 75, as indicated by the thick line with arrow K, dries the components assembled inside the print head 2, such as the nozzle 21, charging 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 operate the pump (for recovery) 35, whereby a portion of the air is sucked through the gutter 25 and then pumped and sent under pressure to the ink container 31 of the main body 1, as indicated by the bold line of the arrow M. In the ink circulation path (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 air is sucked through the nozzle 21 and then pumped and sent under pressure to the ink container 31 of the main body 1, as indicated by the bold line of the arrow N. The air that has flowed into the ink container 31 is then exhausted to the outside of the main body 1 through the exhaust path 805, as indicated by the bold line of the arrow P. In this way, by sucking air through the gutter 25 and the nozzle 21 during the head drying process, the amount of solvent gas emitted around the head cleaning unit 4 can be reduced. If the flow rate of air sucked from inside the cleaning tank 71 by the gutter 25 and the 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, Figure 9 is a fluid path diagram showing the flow of ink, solvent, and air using bold lines when the ink 68A circulation control, ink 68C replenishment control, and solvent 69A-69B replenishment control are being performed during operation of the inkjet recording apparatus 600 of this embodiment. In Figure 9, the inkjet recording apparatus 600 shows that the print head 2 is removed from the head cleaning unit 4 and is ready to print. In the ink supply paths 801-803, the solenoid valve (supply) 49 is energized to open the flow path and operate the pump (supply) 34. As shown by the bold lines of arrows Q and R, ink 68A stored in the ink container 31 of the main body 1 is supplied to the nozzles 21 of the print head 2 and ejected from the nozzles 21 as ink droplets 68B.

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

[0055] In the inkjet recording apparatus 600, the solvent component of the ink 68A is discharged outside the apparatus as solvent gas. Therefore, as the operating time increases, the ratio of the solvent component in the ink 68A decreases, resulting in a high ink concentration. 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. This sends the ink 68A from the ink container 31 to the viscosity measuring device 45, as indicated by arrows V and W, and periodically measures the ink concentration. This 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 ink 68C from the auxiliary ink container 32 if the ink concentration is low. If the ink concentration is high, the control unit 10 controls the ink container 31 to be replenished with recovered solvent 69B from the recovery container 73 or the ink container 31 to be replenished with solvent 69 from the solvent container 33.

[0056] In the ink supply paths (paths 811 and 802), the solenoid valve (ink supply) 54 is energized to open the flow path, and the solenoid valve (supply) 49 is de-energized to close the flow path, and the pump (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, whereby 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 replenishing paths 809-810, when the concentration of the ink 68A is high and it is detected that the liquid level in the recovery container 73 is below the minimum liquid level detection section 76B of the liquid level sensor 76, the solenoid valve (for solvent replenishing) 53 is energized to open the flow path and the pump (for solvent) 37 is operated, whereby the solvent 69A stored in the solvent container 33 is replenished to the ink container 31.

[0058] Next, Figure 10 is a fluid path diagram showing the flow of ink with bold lines when the inkjet recording apparatus 600 of this embodiment has the print head 2 set in the head cleaning unit 4 and is undergoing an ink circulation process. Even if the inkjet recording apparatus 600 is not used for a period of about one to two weeks, it is possible to reduce problems at the start of operation the next time the apparatus is used by periodically circulating the ink (about once every two to three days). Therefore, in Figure 10, we will explain the control required to automatically circulate ink 68A periodically.

[0059] In the ink supply path (paths 801 to 803), the solenoid valve (for supply) 49 is energized to open the flow path and operate the pump (for supply) 34, whereby 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 particles 68B, as indicated by the thick arrow AA.

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

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

[0062] Furthermore, in the inkjet recording apparatus 600, it is also possible to perform periodic automatic head cleaning control in addition to periodic automatic control of the circulation of the ink 68A, which makes it possible to further prevent problems the next time the apparatus is used.

[0063] <Print head structure> Next, the specific configuration of the print head 2 of the inkjet recording apparatus 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 comprises a head base 16, a conduit (for the print head) 5 connecting the main body 1 and the print head 2, and a protective cover 17 attached to the head base 16, which forms a printing opening 17A through which ink particles 68B used for printing pass. The head base 16 is also fitted 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 fitted with a temperature sensor A27 which detects the ambient temperature and uses it for various controls. With the protective cover 17 attached, the space enclosed 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 arrow DC or in the direction opposite to arrow DC (arrow DO).

[0066] Protective cover 17 forms a seat portion 17D, and a door closing spring 19 is attached to seat portion 17D in a state in which a load is applied to protective cover door 18 in the direction of arrow DC. When the door closing spring presses the back surface of opening / closing support portion 18A formed on protective cover door 18 in the direction of arrow DC, protective cover door 18 covers cleaning opening 17B. At this time, protective cover door 18 comes to rest at a position where opening lower end 17C formed on protective cover 17 and door lower end 18C formed on protective cover door 18 abut.

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

[0068] Next, referring to Figure 11(b), the state in which the protective cover door 18 of the print head 2 is open will be described. The open / close 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 compressed. The protective cover door 18 then comes to rest at a position where the door bottom end 18C and the opening upper end 17E of the protective cover 17 come into contact. The proximity sensor A28 attached to the protective cover 17 can detect when the distance to the magnet A29 attached to the protective cover door 18 is below a certain distance.

[0069] 11, protective cover door 18 is of a sliding type that automatically opens when the print head is inserted into cleaning tank 71, but the present invention is not limited to this. That is, 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. For example, the protective cover may be formed with a door that can be opened and closed vertically or horizontally. Alternatively, 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 installed on top of the cleaning tank 71 and having a print head insertion section 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. The lid member 83 is formed with 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 become wet 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 toward 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 and for spraying the solvent 69A toward the nozzle 21, a liquid discharge hole B section 74C connected to the liquid flow path section 74A and for spraying the solvent 69A toward the deflection electrode 24, and a liquid discharge hole C section 74D connected to the liquid flow path section 74A and for spraying the solvent 69A toward the surface of the protective cover 17 on which the printing opening 17A is formed. The liquid flow path section 74A formed in the cleaning nozzle 74 is 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 containing the print head 2 during head cleaning. The cleaning tank 71 has a side wall 71A formed to prevent the solvent 69A sprayed from the cleaning nozzle 74 from splashing around, and a liquid outlet 71D for allowing 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 71C formed at an angle so that the liquid outlet 71D is at its lowest position, making it easier for the solvent 69A to collect at the liquid outlet 71D. A temperature sensor B84 is installed inside the cleaning tank 71 to detect the ambient temperature of the head cleaning unit 4 and use the information 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 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 a 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] The recovery container 73 has a filter (for recovery container) 77 attached to the bottom of the liquid storage section 73A to remove foreign matter that may have become mixed into the recovered solvent 69B during head cleaning or other procedures. A liquid reservoir 73B for storing the filtered recovered solvent 69B is formed below the filter (for recovery container) 77. The recovery container 73 has a solvent reuse flow path 73C connected to the liquid reservoir 73B, and the solvent reuse flow path 73C is connected to a tube 823A via a reuse joint 80. This tube 823A forms part of the solvent reuse paths 823-824 and 807, and the recovered solvent 69B is replenished to the ink container 31 via the tube 823A.

[0079] The recovery container 73 is also formed with a liquid discharge flow path 73D connected to the liquid reservoir 73B, and the liquid discharge flow path 73D is connected via a discharge joint A81 to a tube 86 made of a fluorine-based solvent-resistant material. A discharge joint B87 is attached to the tube 86 by press-fitting the end of the tube 86 into the outlet portion opposite 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 with a nut 89. A seal member 88 is attached to the tube fixing portion 71G. The seal member 88 seals the gap between the discharge joint B87 and the cleaning tank 71 to prevent the solvent 69A from leaking out of the cleaning tank 71 and the recovery container 73.

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

[0081] Furthermore, 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 press-fitting or other methods. This tube 822A forms 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 press-fitting or other methods. This tube 825A forms 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 of the inkjet recording apparatus 600 according to the first embodiment, with the print head 2 set in the head cleaning unit 4, 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 according to the first embodiment. Figure 14 is an enlarged view of the print head 2 and cleaning nozzle 74, and the configuration in the vicinity thereof, shown in Figure 13.

[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 portion 72A. The print head 2 is pushed into a position where the nozzles 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 in the print head insertion portion 72A with the outer wall surface of the print head 2 to prevent misalignment with the print head 2. Furthermore, the head base 16 of the print head 2 comes to rest in a position where it abuts against the print head support portion 71B formed in the cleaning tank 71, so 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 the proximity sensor B90 can detect when the distance between the magnet B30 and the proximity sensor B90 becomes less than a certain distance. When the print head 2 is set in the head cleaning unit 4, the magnet B30 and the proximity sensor B90 become less than the certain distance, so the proximity sensor B90 is detecting them, and it can be determined that the print head 2 is set in the head cleaning unit 4.

[0086] Furthermore, 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. Because the weight of the print head 2 is greater than the spring force of the door closing spring 19, 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 protective cover door 18 does not move below the door support portion 72D, leaving the cleaning opening 17B that was covered by the protective cover door 18 open. 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 less than a certain distance, and therefore 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 head cleaning process is performed with the print head 2 set in the head cleaning unit 4 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 apparatus 600 performs a head cleaning process by spraying solvent 69A from cleaning nozzle 74 to clean the print head 2. The solvent 69A supplied to the cleaning nozzle 74 is sprayed in the directions indicated by arrow EE (the direction in which the solvent 69A is sprayed from liquid discharge hole A portion 74B toward the nozzle 21) and arrow FF (the direction in which the solvent 69A is sprayed from liquid discharge hole B portion 74C toward the deflection electrode 24). The solvent 69A enters the inside of protective cover 17 through cleaning opening 17B and is sprayed onto components such as nozzle 21 and deflection electrode 24 assembled to the print head 2, thereby cleaning away stains caused by ink 68A that have adhered during operation or maintenance of the inkjet recording apparatus 600.

[0089] The solvent 69A sprayed onto the nozzles 21, deflection electrodes 24, and other components assembled to the print head 2 drips and flows due to gravity in the direction indicated by 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 can be sprayed in the direction indicated by 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), spraying the solvent 69A onto the protective cover 17 and cleaning away stains from the ink 68A adhering to the outside of the print head 2.

[0090] During the head cleaning process, the solvent 69A that has cleaned components such as the nozzle 21, charging electrode 23, deflection electrode 24, gutter 25, and protective cover 17 arranged on the print head 2 drips in the directions indicated by arrows JJ and KK, flows into a recovery container 73 installed at the bottom of the head cleaning unit 4, and is collected 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 is not detecting either the maximum liquid level detection unit 76A or the minimum liquid level detection unit 76B. (b) of FIG. 16 shows a state in which the liquid level sensor 76 is detecting the maximum liquid level detection unit 76A because the liquid level of the recovered solvent 69B in the collection container 73 has increased. (c) of FIG. 16 shows a state in which the liquid level sensor 76 is detecting the minimum liquid level detection unit 76B because the liquid level of the recovered solvent 69B in the collection container 73 has decreased.

[0092] In FIG. 16(a), the liquid level sensor 76 installed inside the recovery container 73 includes a float 76C that moves up and down with the liquid level 69C of the recovered solvent 69B; a maximum liquid level detector 76A that is installed below the liquid outlet 71D of the cleaning tank 71 and detects when the float 76C approaches; and a minimum liquid level detector 76B that is installed below the maximum liquid level detector 76A but above the filter (for the recovery container) 77 and detects when the float 76C approaches. The float 76C is not detected by either the maximum liquid level detector 76A or the minimum liquid level detector 76B. In this state, the recovered solvent 69B contained in the recovery container 73 can be properly replenished to the ink container 31. The inkjet recording apparatus 600 can also perform a head cleaning process by placing the print head 2 in the head cleaning unit 4 and spraying 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 detector 76A because the amount of recovered solvent 69B in the recovery container 73 has increased. Repeated head cleaning operations increase the amount of recovered solvent 69B in the recovery container 73, causing the liquid level C to rise. The liquid level sensor 76 determines that the amount of recovered solvent 69B has increased because the float 76C, which displaces in conjunction with the liquid level 69C, and the maximum liquid level detector 76A are approaching a certain distance or less. Upon detecting this state, the inkjet recording apparatus 600 controls the cleaning nozzle 74 so that the solvent 69A is not sprayed to prevent the recovered solvent 69B from overflowing from the recovery container 73.

[0094] Next, referring to FIG. 11C, a state will be described in which the liquid level sensor 76 detects the minimum liquid level detector 76B because the amount of recovered solvent 69B in the recovery container 73 is low. Because the head cleaning process has not been performed for a certain period of time, the amount of recovered solvent 69B in the recovery container 73 is low, causing the liquid level 69C to be low. The liquid level sensor 76 determines that the amount of recovered solvent 69B is low because the float 76C, which moves in conjunction with the liquid level, and the minimum liquid level detector 76B are approaching a certain distance or less. When this state is detected, the inkjet recording apparatus 600 controls the ink container 31 to be replenished with solvent 69A from the solvent container 33, adjusting the solvent concentration of the ink 68A, because the recovered solvent 69B contained in the recovery container 73 cannot be properly replenished to the ink container 31.

[0095] Next, the operation of draining the recovery container 73 of the inkjet recording apparatus 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 during the operation of draining the recovery container 73. In the inkjet recording apparatus 600, if the amount of recovered solvent 69B in the recovery container 73 increases and the liquid level sensor 76 detects the maximum liquid level detector 76A, the head cleaning process cannot be performed. In this case, when performing the head cleaning process, it is necessary to reduce the amount of recovered solvent 69B in the recovery container 73 so that the maximum liquid level detector 76A does not detect the amount of recovered solvent 69B. One method for doing this is to replenish the recovered solvent 69B in the recovery container 73 to the ink container 31, but it may take some 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 positioned 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 simply by 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 apparatus 600, it is possible to reduce the effort required to dispose of the recovered solvent 69B after the head cleaning operation and to reduce the amount of recovered solvent 69B that is disposed of, and therefore it is possible to provide an inkjet recording apparatus 600 that enables customers to reduce their running costs.

[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 that are different from the first embodiment.

[0099] <Exterior configuration> Figure 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. Figure 19 is a perspective view showing the inkjet recording apparatus 700 in this embodiment with print head 2 attached to cleaning tank 271.

[0100] 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 the print head) 5. The main body 201 has a maintenance door 9 on its front. Inside the maintenance door 9, a container base 95 is attached to the bottom, and circulation system components such as an auxiliary ink container 32, a solvent container 33, a head cleaning unit 204, and a drive unit 203 are attached to the container base 95. A maintenance door handle 94 is attached to the top center of the maintenance door 9, making it easy for an operator to open and close the maintenance door 9. By opening the maintenance door 9, the inkjet recording device 700 can perform daily maintenance tasks, such as refilling the auxiliary ink container 32 with ink 68A, refilling the solvent container 33 with solvent 39A, and using the head cleaning unit 204 to clean the print head 2 with solvent 69A.

[0101] The inkjet recording apparatus 700 shown in Figure 18(b) is in a state where the maintenance door 9 is open and the head cleaning unit 204 has been pulled out towards the front. The maintenance door 9 can be opened up to an angle of 90 degrees, and a rail 296 is formed on the back 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 in order to simplify the components.

[0102] Next, with reference to Figure 19, we will explain the state in which the print head 2 is set in the head cleaning unit 204 of the inkjet recording device 700. The print head 2 is inserted, tip first, into the print head insertion section 72A of the head cleaning unit 204. By setting the print head 2 in the head cleaning unit 204 in this way, the inkjet recording device 700 of this embodiment is able to clean the print head 2.

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

[0104] The 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 the path 841 via a connection part (for head cleaning) 59A and a joint (for head cleaning) 260A for relaying with the drive unit 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 then 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 that holds recovered solvent 69B that flows in under its own weight after being used for head cleaning, and a filter (for the recovery container) 77 is attached to the recovery container 73 to prevent foreign matter that has been mixed in during head cleaning from flowing 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 being mixed in the ink 68A.

[0107] A solenoid valve (solvent reuse) 57 for opening and closing the flow path is connected to the filter (solvent reuse) 44, and a path 842 in which the solenoid valve (solvent reuse) 57 is arranged is connected to a path 824 via a connector (solvent reuse) 59B and a joint (solvent reuse) 260B for relaying with the drive unit 203. 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 recovered solvent 69B held in the recovery container 73 to be replenished to the ink container 31, and for it to 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, a drive unit 203 housed in a 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 that communicates with the inside of the main body 201. The pump (for supplying dry air) 38 is connected to an air nozzle 75 provided inside a cleaning tank 71 of a 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 that has improved installation properties.

[0110] Other Examples Although the first and second embodiments have been described above, the present invention is not limited to the first embodiment and includes various modifications. Furthermore, 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...Lower end of opening, 17D...Seat portion, 17E...Upper end of opening, 18...Protective cover door, 18A...Opening / closing support portion, 18B...Olong hole portion, 18C...Door lower end, 18D...Door upper end, 19...Door closing bar 20...pin, 21...nozzle, 21A...discharge port, 23...charging electrode, 24...deflection electrode, 25...gutter, 25A...gutter discharge port, 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 solvent recycling), 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 viscosity measurement), 53...Solenoid valve (for solvent replenishment), 54...Solenoid valve (for ink replenishment), 55...Solenoid valve (for nozzle cleaning), 56...Solenoid valve (for head cleaning), 57...Solenoid valve (for solvent recycling), 58...Storage area, 59A...Connection (for head cleaning), 59B...Connection (for solvent recycling), 60A...Connection hand (for head cleaning), 60B...joint (for solvent reuse), 61A...sealing plug (for solvent supply), 61B...sealing plug (for solvent reuse), 63...start button, 64...stop button, 65...display, 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, 71C...conical inner bottom, 71D...liquid outlet, 71E...sensor mounting portion, 71F...communication hole, 71G...tube fixing portion, 72...lid block, 72A...print head insertion portion, 72B...liquid flow path portion, 72C...air flow path portion,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 solvent reuse), 271... cleaning tank, 273... recovery 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 replenishment), 811...Route (for ink replenishment), 812...Route (for nozzle cleaning), 821 to 822...Route (for head cleaning), 823 to 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...Confluence route (for supply), 902...Confluence 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 includes an ink container that contains ink for printing on a print target and supplies the ink to the print head, and a solvent container that contains solvent and supplies the solvent to the print head; the print head unit has a nozzle connected to the ink container and ejecting pressurized ink, a charging electrode that charges ink droplets ejected from the nozzle, a deflection electrode that deflects the ink droplets charged by the charging electrode, and a gutter that collects ink not used for printing; Further, a head mounting unit configured to be able to mount the print head unit is provided, 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, the tip of the print head is surrounded by the peripheral wall.

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 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 is characterized in that the head cleaning unit performs periodic automatic head cleaning control.

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

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 that charges ink droplets ejected from the nozzle, a deflection electrode that deflects the ink droplets charged by the charging electrode, and a gutter that collects ink not used for printing; Further, a head mounting unit configured to be able to mount the print head unit is provided, The head mounting unit is an inkjet recording apparatus including 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 inkjet recording apparatus is characterized in that 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 inkjet recording apparatus is characterized in that the head detection means detects the installation of the print head by utilizing magnetic force.

10. The inkjet recording apparatus according to any one of claims 7 to 9, The inkjet recording apparatus is characterized in that the head cleaning unit performs periodic automatic head cleaning control.

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

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 as a result of the overflow detection, control is performed 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 formed with 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, the tip of the print head is surrounded by the peripheral wall.

14. The inkjet recording apparatus according to any one of claims 7 to 13, An inkjet recording apparatus characterized in that control is performed to suck solvent gas during cleaning of the print head unit from at least one of the gutter and the nozzles of the print head unit.

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