INKJET PRINTING APPARATUS AND METHOD FOR MANAGING INKJET PRINTING APPARATUS

Abstract

To provide an inkjet recording device, which can prevent ink from adhering during pausing and when viscosity of ink in a main ink container deviates from a range of adequate viscosity, can adjust the viscosity of ink so that the viscosity is in the range of adequate viscosity.SOLUTION: An inkjet recording device is configured to control a printing head and a main body, so that processing of supplying a solvent stored in a solvent container to the printing head and processing of returning of the solvent to an ink container through a circulation passage and a recovery passage are performed repeatedly for each constant time during pausing of printing by the printing head, and which is further configured to dispose portion of ink stored in the ink container from the printing head through a supply passage into a head attachment unit, with the printing head attached to the head attachment unit and to supply the solvent stored in the solvent container to the ink container so as to reduce viscosity of the ink stored inside the ink container, when the viscosity of ink measured by a viscosity measuring part is higher than a previously set predetermined range.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an inkjet printing apparatus and a method for managing the inkjet printing apparatus. [Background technology]

[0002] Products conveyed by the conveying device on the manufacturing line are used as the printing target, and characters and figures are printed on them. In other words, as an inkjet recording device for marking, the nozzles of the print head are covered with The ink is ejected from the nozzle toward the object to be printed without contacting the object. For example, packaging materials such as cardboard boxes in which products are packed are used. When printing characters on the surface of the packaging material, ink is applied to the outer surface of the packaging material while it is being transported by a conveyor. The marking is done by a jet recording device, and the marking is done on the containers that hold food and beverages. The outer surface of the container is printed on while it is being transported by a device.

[0003] The print head of such an inkjet recording device is provided with a charging electrode that charges ink droplets ejected from the nozzle with an amount of charge according to the printing information, and a deflection electrode that deflects the charged ink droplets, and a gutter is disposed opposite the nozzle to recover ink not used for printing. An ink supply path that supplies ink in an ink container is connected to the nozzle, and a recovery path that recovers the ink recovered by the gutter back into the ink container is connected between the gutter and the ink container. In addition, a suction path is connected between the inlet of the nozzle and the ink container to prevent clogging of the nozzle by sucking outside air into the nozzle. Furthermore, a solvent supply path is connected between the solvent container and the nozzle to clean the nozzle and each of the above-mentioned paths.

[0004] The inkjet recording device further has a device main body in which an ink container, a solvent container, etc. are built, and the print head is connected to the device main body by conduits having piping such as hoses that form the respective paths.

[0005] Patent Document 1 discloses an example of a conventional inkjet recording device, which includes "an ink container for storing ink for printing on a print target, a nozzle connected to the ink container and ejecting ink supplied under pressure, a charging electrode for charging ink particles ejected from the nozzle, a deflection electrode for deflecting ink particles charged by the charging electrode, a gutter for recovering ink not used for printing, a solvent container for storing solvent, and a liquid nozzle connected to the solvent container and ejecting the solvent supplied under pressure, wherein the liquid nozzle has a liquid flow path portion extending from the nozzle toward the gutter, and a liquid ejection hole portion formed at an angle such that the solvent supplied under pressure hits the nozzle via the liquid flow path portion."

[0006] Furthermore, Patent Document 2 discloses "an inkjet recording apparatus comprising an ink container for storing ink for printing on a print target, a nozzle connected to the ink container and ejecting pressurized ink, a charging electrode for charging ink particles ejected from the nozzle, a charging signal generating unit for generating a charging signal for charging the charging electrode, a deflection electrode for deflecting ink particles charged by the charging electrode, a gutter for collecting ink not used for printing, and a control unit for controlling the entire operation, wherein the inkjet recording apparatus further comprises a first charge detection means for detecting an amount of charge due to charging of the ink particles between the charging electrode and the deflection electrode, and a second charge detection means for detecting an amount of charge of the ink flowing in the gutter."

[0007] Furthermore, Patent Document 3 also discloses an inkjet recording apparatus having a nozzle for ejecting ink particles that are generated, a charging electrode for charging the ejected ink particles with a character or image signal, a deflection electrode for deflecting the charged ink particles, a gutter for capturing ink particles that are not used to form characters or images, a main ink tank in which the ink particles captured in the gutter are returned to reuse the ink for forming characters or images, an ink refilling means for refilling the main ink tank with the amount of refill ink used to form characters or images, and a refill liquid refilling means for refilling the main ink tank with the amount of volatilized refill liquid, and a liquid volume detection means for detecting the amount of ink liquid accumulated in the main ink tank, the liquid volume detection means being capable of detecting a plurality of liquid level levels including upper, middle, and lower, and the liquid level to be detected is selected according to the environmental temperature. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2020-49786 A [Patent Document 2] JP 2019-123117 A [Patent Document 3] JP 2007-62071 A Summary of the Invention [Problem to be solved by the invention]

[0009] If the inkjet recording device is left idle for a long period of time without ink or solvent flowing, the ink that has accumulated in the circulation path may harden, and the ink may not flow normally even if the ink circulation is started again when the device is started up.

[0010] Furthermore, when an inkjet recording device is used for a long period of time by repeatedly printing and cleaning the head, the viscosity of the ink in the main ink container may change and fall outside the appropriate viscosity range, becoming either too high or too low.

[0011] Patent documents 1 to 3 do not mention preventing the ink from solidifying when the device is stopped for a long period of time, nor does they mention adjusting the viscosity of the ink in the main ink container to within the appropriate viscosity range if the viscosity falls outside of the appropriate viscosity range.

[0012] The present invention provides an inkjet recording device and a method for managing an inkjet recording device that solves the problems of the conventional technology described above, and that is configured to prevent ink from solidifying during pauses, and that is capable of adjusting the viscosity of the ink in the main ink container to within an appropriate viscosity range if the viscosity falls outside the appropriate viscosity range. [Means for solving the problem]

[0013] In order to solve the above-mentioned problems, the present invention provides an inkjet recording device comprising a print head having nozzles that eject ink and prints on a print target, an ink container that stores ink to be supplied to the print head, a solvent container that stores a solvent, a supply path that supplies ink from the ink container to the print head, a circulation path having a circulating pump that returns a portion of the ink supplied to the print head to the ink container, a recovery path having a recovery pump that sucks up ink ejected from the nozzles of the print head and recovers it in the ink container, a main body having a viscosity measuring unit that measures the viscosity of the ink stored in the ink container, a head mounting unit that mounts the print head, and a control unit that controls the print head and the main body, wherein the control unit is configured to control the print head and the main body so that the viscosity of the ink falls within the predetermined range when the viscosity of the ink measured by the viscosity measuring unit is outside a predetermined range. Furthermore, in order to solve the above-mentioned problems, the present invention provides an inkjet recording device comprising: a print head equipped with nozzles for ejecting ink and for printing on a print object; an ink container for storing ink to be supplied to the print head; a solvent container for storing a solvent; a main body equipped with a supply path for supplying ink from the ink container to the print head, a circulation path for returning a portion of the ink supplied to the print head to the ink container, and a recovery path for sucking up ink ejected from the nozzles of the print head and recovering it in the ink container; and a control unit for controlling the print head and the main body, wherein the control unit is configured to control the print head and the main body while printing on a print object by the print head is paused so as to supply the solvent stored in the solvent container to the print head and return it to the ink container via the circulation path and the recovery path, repeatedly at regular intervals while printing by the print head is paused. Effect of the Invention

[0014] According to the present invention, by supplying the solvent to the print head and ejecting the solvent from the nozzles, it is possible to pass the liquid through the circulation path, thereby improving the effect of preventing adhesion.

[0015] Furthermore, according to the present invention, in the ink jet recording apparatus, it is possible to automatically adjust the viscosity of the ink in the main ink container, including cases where the viscosity is high and cases where the viscosity is low. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a perspective view showing a usage state of the inkjet recording apparatus in the embodiment. [Diagram 2] FIG. 2 is a diagram showing a configuration of paths for flowing ink or a solvent in the inkjet recording device according to the embodiment. [Diagram 3] FIG. 2 is a block diagram showing the configuration of a control unit of the inkjet recording apparatus according to the embodiment. [Figure 4] FIG. 4 is a flow chart of a process for preventing ink adhesion in the inkjet recording device according to the embodiment. [Diagram 5] FIG. 4 is a path diagram showing paths through which ink flows when measuring the viscosity of ink in a process for preventing ink adhesion in an inkjet recording device in an embodiment. [Figure 6] FIG. 11 is a diagram showing paths taken when a solvent is supplied to a print head and then recovered in a process for preventing ink adhesion in an inkjet recording device according to an embodiment. [Figure 7] FIG. 11 is a diagram showing a path when measuring the viscosity of ink while circulating ink inside the main body in a process for preventing ink adhesion in the inkjet recording device in the embodiment. [Figure 8] FIG. 11 is a flow chart showing a process for adjusting the viscosity of ink in an inkjet recording device in an embodiment so that the viscosity of ink falls within a certain range. [Figure 9] FIG. 4 is a path diagram showing a path configuration in a state where the viscosity of ink is measured in the ink jet recording apparatus in the embodiment. [Figure 10] FIG. 11 is a path diagram showing a path configuration in a state where ink is circulated through a print head in a process for adjusting the viscosity of ink so that it falls within a certain range when the viscosity of the ink in the inkjet recording device in the embodiment is high. [Figure 11] FIG. 11 is a path diagram showing a path configuration in a state where ink is being discharged from a print head in a process for adjusting the viscosity of ink so that it falls within a certain range when the viscosity of the ink in the inkjet recording device in the embodiment is high. [Figure 12] FIG. 11 is a path diagram showing a path configuration in which a solvent is supplied to a main ink container while circulating ink in a process for adjusting the viscosity of ink so that it falls within a certain range when the viscosity of the ink in an inkjet recording device in an embodiment is high. [Figure 13] FIG. 11 is a path diagram showing the path configuration in a state where the viscosity of ink in a main ink container is measured while circulating ink in a process for adjusting the viscosity of ink so that it falls within a certain range when the viscosity of ink in an inkjet recording device in an embodiment is high. [Figure 14] FIG. 4 is a path diagram showing a path configuration in a state in which an ink circulation path including a print head is being cleaned in the ink jet recording device in the embodiment. [Figure 15] FIG. 4 is a path diagram showing a path configuration in a state where a print head is being thoroughly cleaned in the ink jet recording device in the embodiment. [Figure 16] FIG. 1 is a path diagram showing the path configuration in a process of adjusting the viscosity of ink so that it falls within a certain range when the viscosity of ink in an inkjet recording device in an embodiment is low, in which the viscosity of ink in the main ink container is measured while ink is being replenished from the auxiliary ink container to the main ink container via the print head. [Figure 17] FIG. 11 is a front view of an operation display unit showing an ink viscosity display area that displays an initial value of ink viscosity and a value after adjustment in the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The present invention makes it possible to supply solvent to the print head and eject the solvent from the nozzles at regular time intervals while the inkjet recording device is at rest, thereby causing the liquid to flow through the circulation path.

[0018] Furthermore, the present invention is directed to an ink jet recording apparatus that is capable of automatically adjusting the viscosity of ink depending on whether the viscosity is high or low when the viscosity of the ink falls outside a predetermined range.

[0019] Furthermore, in the present invention, when the viscosity of the ink in an inkjet recording device becomes higher than a predetermined range, the viscosity of the ink can be adjusted to an appropriate range simply by discarding a portion of the ink contained in the main ink container according to the viscosity of the ink. This eliminates the need to discard all of the ink in the main ink container and replace it with new ink, reduces the amount of ink discarded, and increases the effective amount of ink used.

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In all the drawings for explaining the embodiment, the same reference numerals are used to denote the same functions, and the repeated description is omitted as a rule.

[0021] However, the present invention should not be construed as being limited to the description of the embodiments shown below. It will be easily understood by those skilled in the art that the specific configurations can be modified without departing from the concept or spirit of the present invention. EXAMPLES

[0022] <Usage status> First, the usage state of the inkjet recording apparatus in the first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a perspective view showing the usage state of the inkjet recording apparatus in the first embodiment of the present invention.

[0023] 1, inkjet recording devices 600A and 600B have the same configuration, and each comprises a main body 1, a print head 2 connected to the main body 1 by a cable (for the print head) 5, and a head mounting unit 3 connected to the main body 1 by a cable (for the head mounting unit) 6. Here, the head mounting unit 3 basically has the function of accommodating the print head, but may also have the added function of spraying a cleaning liquid to clean the print head.

[0024] The head mounting unit 3 described below has a configuration that adds a function for cleaning the print head. Inkjet recording device 600A shows a state in which the print head 2 is installed on a production line. Inkjet recording device 600B shows a state in which the print head 2 has been removed from the production line and mounted (set) on the head mounting unit 3. Note that a collection container 4 attached to the bottom of the head mounting unit 3 is provided to store liquid (cleaning liquid) after the print head is cleaned by the head mounting unit 3.

[0025] Inkjet recording device 600A 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 X on the production line such as belt conveyor 11. In addition, protective cover 17 is attached to print head 2 in order to protect the parts inside print head 2. Note that print object 12B is shown in a state where printing by print head 2 has been completed and it is being transported on belt conveyor 11.

[0026] In FIG. 1, main body 1 contains (holds) ink for printing, and controls the drive unit (pump and solenoid valve) inside the main body to supply ink to print head 2 via cable (for print head) 5. The internal path configuration of main body 1 and details of the control unit will be described later. Operation display unit 8 is installed on the top surface of main body 1, and uses a touch input display panel here. By touching operation of operation display unit 8, the operator can instruct the control unit to start or stop the device, set the content to be printed on print target 12A, and display information on ink viscosity before and after adjustment. In FIG. 1, 16 in print head 2 denotes a head base.

[0027] The head mounting unit 3 is installed around the print head 2. The head mounting unit 3 in the inkjet recording device 600A is fixed by combining a fixing jig 92 attached to the belt conveyor 11 with a fitting part 93 attached to the head mounting unit 3. The head mounting unit 3 has a head mounting part 81A for mounting the print head 2. The head mounting unit 3 also has a start button 18 for starting the cleaning process of the print head 2, a stop button 19 for stopping the cleaning process of the print head 2, and a display unit 15 for displaying confirmation messages, warnings, abnormalities, and other alarms to the operator. The display unit 15 may be configured to allow the operator to recognize the operating state and the presence or absence of abnormalities, for example, by the presence or absence of a light or by differences in color.

[0028] In the inkjet recording device 600A of this embodiment, the head mounting unit 3 is fixed near the belt conveyor 11, but the head mounting unit 3 can be freely moved to a location that is easy for the user to operate. The length of the cable (for the head mounting unit) 6 connecting the main body 1 and the head mounting unit 3 is preferably the same as or longer than the cable 5 connecting the main body 1 and the print head 2 of the inkjet recording device 600. This is to ensure the freedom of positioning the head mounting unit.

[0029] The main body 1 also has a fixing part 91 for fixing the head mounting unit 3, and the head mounting unit 3 can be removed from the fixing jig (for conveyor) 92 and replaced with the fixing part 91 for use. The inkjet recording device 600B shows such a state.

[0030] In the inkjet recording device 600B, the head mounting unit 3 is shown fixed to the main body 1 by combining a mating part 93 with a fixing part 91 attached to the main body 1. By making it possible to fix the head mounting unit 3 to the main body 1, it becomes possible to install the head mounting unit 3 even when there is no space to install the head mounting unit 3 near the belt conveyor 11, for example.

[0031] Next, the state in which the print head 2 is set in the head mounting unit 3 in the inkjet recording device 600B will be described. The print head 2 is set by mounting the tip of the print head 2 to the head mounting part 81A of the head mounting unit 3. By setting the print head 2 in the head mounting unit 3 in this manner, the inkjet recording device 600B in this embodiment can clean the print head 2 with solvent 69A supplied from the main body 1 side via the cable (for the head mounting unit) 6.

[0032] In the inkjet recording device 600A, the print head 2 can be similarly cleaned when it is set in the head mounting unit 3 which is fixed by combining a fitting portion 93 with a fixing jig 92 attached to the belt conveyor 11.

[0033] <Route configuration> Next, the path configuration of the inkjet recording apparatus 600 (the inkjet recording apparatus 600A and the inkjet recording apparatus 600B shown in FIG. 1 are collectively referred to as the inkjet recording apparatus 600) in the first embodiment will be described with reference to FIG. 2. FIG. 2 is a diagram showing the overall path configuration of the inkjet recording apparatus 600 in this embodiment.

[0034] First, the ink supply paths (paths 801 to 803) of the inkjet recording device 600 in the first embodiment will be described. In Fig. 2, the main body 1 is provided with a main ink container 31 that holds ink 68A for printing. The main ink container 31 is provided with a liquid level sensor 31A (sensor 1) that detects a state in which the liquid (ink 68A) in the main ink container 31 exceeds a reference liquid level that is an appropriate amount to be held inside, a liquid level sensor 31B (sensor 2) that detects whether the liquid level reaches the reference liquid level that is an appropriate amount, and a liquid level sensor 31C (sensor 3) that detects the end point of the amount of ink discarded when discarding ink from the main ink container 31.

[0035] The main 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.

[0036] 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 38 that measures the pressure of the ink 68A supplied to the nozzles 21. A path 802 in which the pressure regulating valve 46 is arranged is connected via a branch path 921 to a path 803 that passes through the inside of the cable (for print head) 5, and the path 803 is connected to a switching solenoid valve 26 provided in the print head 2 for controlling whether or not to supply the ink 68A to the nozzles 21.

[0037] A heater 20 is installed in front of the solenoid valve (for switching) 26 to heat the ink 68A to an optimum temperature to be supplied to the nozzles 21. The heater 20 includes an internal temperature sensor for heating control (not shown).

[0038] The solenoid valve (for switching) 26 is connected to the nozzle 21 that ejects the ink 68A via a filter 27. The solenoid valve (for switching) 26 is a three-way solenoid valve, and an ink supply path 803 and a nozzle cleaning path 825 are connected to the solenoid valve (for switching) 26, so that the supply of the ink 68A and the solvent 69A to the nozzle 21 can be switched. In the straight direction of the ink droplets 68B ejected from 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.

[0039] Next, the ink recovery paths 811 and 812 of the inkjet recording apparatus 600 will be described. In Fig. 2, the gutter 25 is connected to the path 811, and a charge sensor 48 is disposed in the path 811 for detecting whether ink particles 68B to which an electric charge has been added by the charging electrode 23 are being recovered. The path 811 passes through a cable (for print head) 5 and is connected to a filter (for recovery) 40 that removes foreign matter mixed in the ink and is 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.

[0040] The solenoid valve (for recovery) 50 is disposed in a path 812 connected via a junction path 902, and is connected to a pump (for recovery) 35 that sucks up the ink particles 68B captured by the gutter 25. The pump (for recovery) 35 is connected to the main ink container 31. By opening the solenoid valve 50 and driving the pump (for recovery) 35, the ink particles 68B captured by the gutter 25 are recovered into the main ink container 31 through paths 811 and 812.

[0041] Next, the exhaust path (path 814) of the inkjet recording apparatus 600 in this embodiment will be described. The main ink container 31 is connected to the path 814 in an upper space that does not contact the ink 68A, and the path 814 is connected to the exhaust duct connection part 62 that communicates with the outside of the main body 1.

[0042] Next, the ink circulation paths (paths 821 and 822) of the inkjet recording device 600 in this embodiment will be described. The nozzles 21 provided in the print head 2 are connected to a path 821 that passes through the cable (for print head) 5, in addition to the path to which the ink 68A is supplied via the filter 27. In this path 821, a solenoid valve (for circulation) 59 that is provided in the main body 1 and opens and closes the path (flow path) is disposed. The solenoid valve (for circulation) 59 is connected to a path 822 via a junction path 903, and a pump (for circulation) 36 that sucks ink from the nozzles 21 is disposed in the path 822. The pump (for circulation) 36 is connected to the main ink container 31 via the path 822.

[0043] Next, a description will be given of the viscosity measurement paths (824 and 822) of the inkjet recording apparatus 600 in this embodiment. In Fig. 2, the main ink container 31 is connected to a path (for viscosity measurement) 824 at a portion immersed in the ink 68A.

[0044] The path (for viscosity measurement) 824 is connected to a filter (for viscosity measurement) 42 for removing foreign matter mixed in the ink 68A supplied from the main ink container 31, and is further connected to a viscosity measuring device (viscometer) 45 for grasping the viscosity of the ink 68A in the main ink container 31.

[0045] The viscosity measuring device (viscometer) 45 is connected to an electromagnetic valve (for viscosity measurement) 57 that opens and closes the path. The electromagnetic valve (for viscosity measurement) 57 is connected to the pump (for circulation) 36 arranged in the path 822 via a junction path 903.

[0046] This allows the ink 68A in the main ink container 31 to be circulated through the viscosity measurement path, and the viscosity of the ink 68A can be measured by the viscosity measuring device (viscometer) 45. Information relating to the viscosity measured in this manner is input to the control unit 7 and used to control the viscosity of the ink 68A in the main ink container 31.

[0047] Next, the solvent supply paths (paths 831 and 833) of the inkjet recording apparatus 600 in this embodiment will be described. In Fig. 2, the main body 1 is provided with a solvent container 33 that holds a solvent 69A to be used for supplying solvent to the main ink container 31, or for cleaning the nozzles or heads. A solvent cartridge 69B that contains a solvent for supply is attached to the solvent container 33.

[0048] The solvent container 33 is connected to a path 831 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 831. The pump (for solvent) 37 is connected to a branch path 922 to change the supply destination of the solvent 69A depending on the purpose.

[0049] In the solvent supply path, the branch path 922 is connected to an electromagnetic valve (for solvent supply) 53 to open and close the path arranged in path 833, and the electromagnetic valve (for solvent supply) 53 is configured to be connected to the main ink container 31 via path 833. Using these paths 831 to 833, viscosity control of the ink 68A in the main ink container 31 is performed under the control of the control unit 7.

[0050] Furthermore, when the solvent 69A evaporates inside the solvent container 33 and the pressure inside the solvent container 33 increases, an exhaust path 816 is connected between the solvent container 33 and the exhaust duct connection portion 62 in order to discharge the evaporated solvent to the outside.

[0051] Next, the ink supply path 806 of the inkjet recording apparatus 600 in this embodiment will be described. In Fig. 2, the main body 1 is provided with an auxiliary ink container 32 that holds refill ink 68C. An ink cartridge 68D that contains refill ink is attached to the auxiliary ink container 32.

[0052] The auxiliary ink container 32 is connected to a path 806 at a portion immersed in the ink 68C. The path 806 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 pump the ink 68C. Then, with the solenoid valve (for ink supply) 54 open and the solenoid valve (for supply) 49 closed, the ink 68C in the auxiliary ink container 32 is ejected from the nozzle 21 through the paths 802-803 and replenished into the main ink container 31 via the gutter 25, the path 811, the solenoid valve 50, and the pump 35.

[0053] Furthermore, in the event that the solvent in the ink 68C evaporates inside the auxiliary ink container 32 and the pressure inside the auxiliary ink container 32 increases, an exhaust path 815 is connected between the auxiliary ink container 32 and the exhaust duct connection portion 62 to discharge the evaporated solvent to the outside.

[0054] Next, the nozzle cleaning paths (paths 831 and 825) of the inkjet recording apparatus 600 in this embodiment will be described. In FIG. 2, the pump (for solvent) 37 disposed in the path 831 is connected to the path 825 via a branch path 922. The path 825 is connected to an electromagnetic valve (for nozzle cleaning) 55 for opening and closing the 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 a path 821 passing through the cable (for print head) 5, and is connected to an electromagnetic valve (for switching) 26 for controlling whether or not the solvent 69A for cleaning is sent to the nozzle 21.

[0055] Next, the main body circulation paths (paths 808 and 812) of the inkjet recording apparatus 600 in this embodiment will be described. Path 802 is connected to path 808 via a branch path 921. Path 808 is connected to solenoid valve (for main body circulation) 58 that opens and closes the path, and solenoid valve (for main body circulation) 58 is connected to pump (for recovery) 35 installed in path 812 via a junction path 902.

[0056] Next, the head cleaning paths (paths 831 and 837) of the inkjet recording apparatus 600 in this embodiment will be described. In Fig. 2, the pump (for solvent) 37 is connected to the path 837 via a branch path 922, and the path 837 is provided with an electromagnetic valve (for head cleaning) 56 for opening and closing the path, and the electromagnetic valve (for head cleaning) 56 is connected to a filter (for head cleaning) 43 for removing foreign matter mixed in the solvent 69A.

[0057] The recovery container 4 attached to the head mounting unit 3 is provided to store the solvent after being washed with the cleaning liquid (solvent) sprayed from the cleaning nozzle 72 installed in the cleaning tank 71 of the head mounting unit 3. A float 74 with a built-in magnet is provided inside the recovery container 4 to detect the liquid level of the solvent after washing. Magnetic sensors 76A and 76B and a magnet 75 are attached to the outside of the recovery container 4 to detect the amount of solvent accumulated inside the recovery container 4. When the float 74 with the built-in magnet 75 reaches a predetermined liquid level, the magnetic sensor 76A detects the magnetism of the magnet 75 built into the float 74 and outputs to the control unit 7 that the cleaning liquid in the recovery container 4 has reached the predetermined liquid level.

[0058] Next, the air supply path (path 841) of the inkjet recording device 600 in this embodiment will be described. In Fig. 2, the main body 1 is provided with a pump (for drying) 60 used to suck and pump air, and the pump (for drying) 60 forms an air suction port communicating with the inside of the main body 1. The pump (for drying) 60 is connected to the head mounting unit 3 via a path 841 that passes through the cable (for head mounting unit) 6.

[0059] Next, the air suction path (path 843) of the inkjet recording apparatus 600 in this embodiment will be described. The cleaning tank 71 provided in the head mounting unit 3 is connected to a pump (for suction) 61 used to suck and pressurize air provided in the main body 1 via a path 843 that passes through a cable (for head mounting unit) 6. The pump (for suction) 61 is connected to an exhaust duct connection part 62 that communicates with the outside of the main body 1.

[0060] <Control Unit Configuration> Next, the configuration of the control unit 7 of the inkjet recording apparatus 600 in this embodiment will be described. Fig. 3 is a diagram showing a schematic configuration of the control unit 7 and the printing mechanism (main body 1 and print head 2) of the inkjet recording apparatus 600 in this embodiment. In Fig. 3, 301 is a microprocessing unit (hereinafter referred to as MPU) which is the control unit that controls the entire inkjet recording apparatus 600.

[0061] A bus line 302 has a function of transmitting data, control signals, etc. between each device constituting the control unit. For example, the bus line 302 is used to input data and detection signals required for the calculation of the MPU 301 from each device and to transmit data signals, address signals, and control signals to each device.

[0062] Reference numeral 306 denotes a read-only memory (ROM) that stores control programs and data necessary for MPU 301 to operate. Reference numeral 307 denotes a rewritable memory (RAM) that temporarily stores data required while MPU 301 is executing a program. Reference numeral 8 denotes an operation display unit that inputs print contents and setting values, etc., and displays the input data and print contents, etc. This operation display unit 8 uses a touch input display panel in which transparent touch switches are superimposed on the surface of a liquid crystal display screen.

[0063] The head mounting unit 3 can be controlled from the operation display unit 8 of the control unit 7, but the operation unit (start button 18 and stop button 19) is used when operating operations related to the head mounting unit 3 near the head mounting unit 3, rather than on the operation display unit 8. The display unit 15 is used when checking the operating status and abnormality messages related to the head mounting unit 3 near the head mounting unit 3, rather than on the operation display unit 8.

[0064] The print head 2 of the inkjet recording device 600 is equipped with a nozzle 21 that atomizes and ejects ink 68A supplied under pressure from the main ink container 31. The nozzle 21 ejects ink in a columnar shape, the tip of which separates and is ejected as ink droplets 68B. The print head 2 also has a charging electrode 23 that surrounds the ink droplets 68B, and charges the ink droplets 68B according to the print content.

[0065] Furthermore, the print head 2 deflects the flying ink particles 68B, which are charged by the charging electrode 23, according to the amount of charge, and makes them fly toward a print target (not shown). Then, printing is performed by the flying ink particles landing on the print target. The deflection electrode 24 of the print head 2 is composed of a ground electrode 24B and a positive electrode 24A. The print head 2 also includes a gutter 25 that captures ink particles 68B (unused ink) that were not used in printing, and a charge sensor 48 that generates a phase detection signal according to the amount of charge of ink particles 68B1 that are slightly charged among the ink particles 68B captured by the gutter 25. The main body 1 also includes a pump (for recovery) 35 that recovers the ink (ink particles) captured by the gutter 25 into the main ink container 31, and ink recovery paths 811-812 that connect the gutter 25 and the main ink container 31.

[0066] The control unit 7 also has an excitation voltage generating circuit 331 that excites an electrostrictive element (not shown) built into the nozzle 21 in order to impart regularity to the timing at which the ink column ejected from the nozzle 21 separates into ink droplets 68B.

[0067] The control unit 7 also has a printing charge signal generating circuit 342 and a phase search charge signal generating circuit 341, a D / A converter 343 that converts the digital signal-type charge signal output from these circuits into an analog voltage signal, and an amplifier circuit 344 that amplifies the analog voltage signal output from the D / A converter 343 to generate a charge voltage to be applied to the charging electrode 23. Instead of providing the printing charge signal generating circuit 342 and the phase search charge signal generating circuit 341, the control unit may use only the printing charge signal generating circuit 342 to control the charge amount. The inkjet recording apparatus 600 also has a deflection voltage generating circuit 332 that generates a deflection voltage to be applied to the deflection electrode 24.

[0068] The inkjet recording apparatus 600 also includes an amplifier circuit 353 that amplifies the phase detection signal in the form of an analog signal output from the charge sensor 48, a phase determination circuit 351 that inputs the amplified phase detection signal and determines whether charging is good or bad, and an A / D converter 352 that inputs the amplified phase detection signal and performs A / D conversion.

[0069] Next, in FIG. 3, the MPU 301 of the control unit 7 is connected via a bus line 302 to a liquid level detection circuit 313 for managing the liquid level in the main ink container 31, a pressure detection circuit 312 for detecting whether the pressure of the ink supplied to the nozzle 21 is an appropriate value, a viscosity measurement circuit 311 for measuring with a viscosity meter 45 whether the viscosity of the ink 68A supplied to the nozzle 21 is an appropriate value for printing, a pump control circuit 314 for controlling each of the pumps 34-37 arranged in the main body 1 that sucks in and pumps out the ink 68A and the solvent 69A, and a solenoid valve drive circuit 315 for controlling the opening and closing operation of each of the solenoid valves 49-50 and 53-59 in each path, and controls each part.

[0070] In addition, the MPU 301 is connected via bus line 302 to a pump control circuit 321 for controlling pumps 60 and 61, a collection container sensor detection circuit 322 for detecting, using a magnetic sensor 76A and a magnet 75, that the collection container 4 is attached to the head mounting unit 3 and that the liquid 70 in the collection container 4 is not greater than a predetermined amount, a print head detection circuit 323 for detecting that the print head 2 is attached to the head mounting unit 3, and a head mounting unit detection circuit 324 for detecting that the print head 2 is attached to the head mounting unit 3, and is configured to control each part.

[0071] The control unit 7 can use a computer. Specifically, the control unit 7 can be composed of an MPU 301, memories (306 and 307) that store programs for the operation of the MPU 301 and data and information required for the operation, and a drive unit that operates the print head 2, the head mounting unit 3, and the components within the main body 1 according to instructions from the MPU 301. A detailed description of the control unit 7 will be omitted here.

[0072] <Prevention of adhesion during pause> The operation of preventing ink from solidifying, which is performed while the print head 2 is attached to the head mounting unit 3 and printing by the print head 2 is paused, will be described with reference to FIGS.

[0073] 4 shows a process flow of the ink adhesion prevention operation. First, while printing by the print head 2 is paused, the MPU 301 of the control unit 7 checks the amount of solvent 69A used to clean the print head 2 inside the solvent container 33 from signals from the level sensors 33A and 33B based on the stored control program, and checks whether the solvent cartridge 69B that contains the solvent for supplying the solvent 69A to the solvent container 33 is replaceable (S401).

[0074] If the level sensor 33B does not detect the solvent 69A inside the solvent container 33, the MPU 301 determines that the amount of the solvent 69A inside the solvent container 33 is small and that the solvent cartridge 69B can be replaced (Yes in S401), and proceeds to S402. On the other hand, if the level sensor 33A detects the solvent 69A inside the solvent container 33, the MPU 301 determines that the amount of the solvent 69A inside the solvent container 33 is sufficient and that the solvent cartridge 69B cannot be replaced (No in S401), and proceeds to the adhesion prevention step (S404).

[0075] If it is determined in S401 that the solvent cartridge 69B can be replaced (Yes in S401), the process proceeds to S402, where, in response to an instruction from the MPU 301, guidance recommending replacement of the solvent cartridge 69B is displayed on the display unit 15 and the operation display unit 8. If, after replacing the solvent cartridge 69B in accordance with the guidance, an interrupt button (not shown) displayed on the display unit 15 and the operation display unit 8 is touched in S403, the operation of preventing adhesion is interrupted. On the other hand, if an execute button (not shown) displayed on the display unit 15 and the operation display unit 8 is touched in S403, the process proceeds to a sticking prevention step (S404).

[0076] In the adhesion prevention step S404, first, the MPU 301 controls the solenoid valve drive circuit 315 to repeatedly open and close the solenoid valve (for ink supply) 54, the solenoid valve (for switching) 26 and the solenoid valve (for head cleaning) 56 (S4041), thereby preventing ink adhering to the solenoid valves 54, 26 and 56 from adhering and impeding the opening and closing operations of the solenoid valves 54, 26 and 56.

[0077] Next, in the solvent evaporation sequence (S4042), the MPU 301 controls the pump control circuit 314 to operate the pump (for recovery) 35, as shown in Fig. 5, to open the solenoid valve (for recovery) 50 and suck air from the gutter 25 via paths (for recovery) 811 and 812, thereby supplying air to the inside of the main ink container 31. The air supplied to the inside of the main ink container 31 is connected to the exhaust duct connection part 62 through path (for exhaust) 814 and exhausted by an exhaust means (not shown). In this way, the air sucked from the gutter 25 is connected to the exhaust duct connection part 62 through the inside of the main ink container 31, whereby the solvent inside the main ink container 31 is evaporated (volatilized).

[0078] The air sucked in from this gutter 25 is connected to the exhaust duct connection part 62 through the inside of the main ink container 31 to volatilize the solvent inside the main ink container 31, and this continues until the liquid level of the ink 68A inside the main ink container 31 drops so that the liquid level sensor 31B no longer detects the ink 68A and the liquid level of the ink 68A reaches the initial level (the level at which the detection of the ink 68A by the liquid level sensor 31B switches from OFF to ON, or vice versa) (S4043).

[0079] This makes it possible to prevent the volume of ink 68A inside the main ink container 31 from increasing too much and exceeding the allowable level due to the ink being recovered from the gutter 25 into the main ink container 31 via paths (for recovery) 811 and 812 while printing with the print head 2, or due to the supply of solvent 69A from the solvent container 33.

[0080] If the pump (for recovery) 35 is operated to suck in air from the gutter 25, and this sucked in air is temporarily stored inside the main ink container 31 and then exhausted from the exhaust duct connection part 62 through the path (for exhaust) 814 for 5 to 10 minutes, the back pressure of the pump (for recovery) 35 will increase and the suction volume of the pump (for recovery) 35 will decrease.

[0081] At this time, while pumps 34 and 35 are operating, solenoid valve 50 is closed and solenoid valves 49 and 58 are opened, thereby circulating ink 68A inside main ink container 31 through paths 801 to 808 and 812 for about one minute, thereby returning the amount of air sucked in from gutter 25 by pump (for recovery) 35 to normal.

[0082] When the level of the ink 68A inside the main ink container 31 returns to the initial level (Yes in S4043), the viscosity of the ink 68A inside the main ink container 31 from which the solvent has evaporated is measured (S4044). To measure the viscosity of the ink 68A, the solenoid valve (for recovery) 50 is closed, and the pump (for circulation) 36 is operated with the solenoid valve (for viscosity measurement) 57 open. In this state, the ink 68A inside the main ink container 31 passes through the filter (for viscosity measurement) 42 and then through the path (for viscosity measurement) 824 to the viscosity meter 45, thereby measuring the viscosity. The ink whose viscosity has been measured by the viscosity meter 45 passes through the solenoid valve (for viscosity measurement) 57 and is returned to the inside of the main ink container 31 again through the path (for head circulation) 822.

[0083] After the viscosity measurement by the viscosity meter 45 is completed, solenoid valve (for viscosity measurement) 57 is closed to stop the supply of ink to the viscosity meter 45. Next, while pump (for circulation) 36 is operating, pump (for solvent) 37 and pump (for recovery) 35 are also operated, and solenoid valve (for nozzle cleaning) 55, solenoid valve (for recovery) 50, and solenoid valve (for circulation) 59 are opened to spray the solvent from the print head 2 (S4045). As shown in FIG. 6, by opening solenoid valves 55, 50, and 59, the following become accessible: a solvent path, shown by a bold line, consisting of path (for solvent supply) 831 connecting the solvent container 33 and solenoid valve (for switching) 26 of the print head 2 and path (for nozzle cleaning) 825; a circulation path, shown by a bold line, consisting of path (for head circulation) 821 connecting the nozzle 21 of the print head 2 and main ink container 31 and path (for head circulation) 822; and a recovery path, shown by a bold line, consisting of path (for recovery) 811 connecting the gutter 25 of the print head 2 and main ink container 31 and path (for recovery) 812.

[0084] In this state, the solvent 69A contained inside the solvent container 33 is sucked up by the pump (for solvent) 37, passes through the solenoid valve (for nozzle cleaning) 55, passes through the path (for solvent supply) 831 and path (for nozzle cleaning) 825 that constitute the solvent path, and is supplied to the nozzle 21 through the solenoid valve (for switching) 26 and the filter 27.

[0085] The solvent supplied to the nozzle 21 passes through a path (for head circulation) 821 constituting a circulation path that is partly connected to the nozzle 21, passes through the solenoid valve (for circulation) 59, and then passes through a path (for head circulation) 822 to be stored in the main ink container 31. On the other hand, the solvent fired forward from the nozzle 21 enters the gutter 25, passes through a path (for recovery) 811 constituting a recovery path, passes through the solenoid valve (for recovery) 50, and is stored in the main ink container 31 through a path (for recovery) 812.

[0086] In this manner, by configuring the solvent 69A contained inside the solvent container 33 to be supplied to the print head 2 via the solvent path and recovered in the main ink container 31 via the circulation path and recovery path, the solvent can be passed through the inside of the solenoid valve (for recovery) 50 and the solenoid valve (for circulation) 59 while the inkjet recording device 600A or 600B is at rest, and the ink remaining inside the solenoid valves 50 and 59 can be dissolved and recovered with the solvent. This makes it possible to prevent malfunction of the solenoid valves 50 or 59 caused by the ink remaining inside the solenoid valves 50 and 59 solidifying while the inkjet recording device 600A or 600B is at rest.

[0087] Furthermore, even if the solvent beam bends and misses the gutter 25 when ejecting the solvent from the nozzle 21 and scatters into the surrounding area, unlike the case of ink, the scattered solvent evaporates without soiling the surrounding area. Therefore, for example, it is possible to simply cover the area around the print head 2 with a beaker or the like to prevent the ink from solidifying, but if the print head 2 is attached to the head mounting unit 3 as in this embodiment, this can be done without preparing something like the beaker described above.

[0088] Furthermore, unlike the case of ink, there is no need to worry about the solvent scattering around and soiling the surrounding area, so the solvent ejection step can be carried out unmanned.

[0089] Next, in order to uniformly dissolve the recovered solvent in the ink 68A inside the main ink container 31, the ink 68A inside the main ink container 31 is circulated (S4046). The ink circulation paths are, as shown by the bold lines in Fig. 7, a path from path (for supply) 801 through path (for main body circulation) 808 to path (for recovery) 812, and a path from path (for viscosity measurement) 824 to path (for head circulation) 822.

[0090] By energizing the solenoid valve (for supply) 49 and the solenoid valve (for circulation in the main body) 58 to open the path, and operating the pump (for supply) 34 and the pump (for recovery) 35, the ink 68A contained in the main ink container 31 flows along a path that leads from path (for supply) 801 through path (for circulation in the main body) 808 to path (for recovery) 812. As a result, the ink 68A coming out of the main ink container 31 passes through the solenoid valve (for supply) 49, the pump (for supply) 34, the filter (for supply) 39, the pressure adjusting valve 46, the solenoid valve (for circulation in the main body) 58, and the pump (for recovery) 35, and circulates back to the main ink container 31.

[0091] In the main body 1, by energizing the solenoid valve (for viscosity measurement) 57 to open the path and operating the pump (for circulation) 36, the ink 68A contained in the main ink container 31 passes through the viscosity meter 45, the solenoid valve (for viscosity measurement) 57, and the pump (for circulation) 36 from the path (for head circulation) 824 along the path (for head circulation) 822, and returns to the main ink container 31, thereby circulating the ink 68A. In this way, if the viscosity of the ink 68A is measured using the viscosity meter 45 at the timing of the ink circulation in the main body 1, it becomes easier to grasp the state of the ink 68A the next time it is used.

[0092] After the ink is circulated for a predetermined period of time, the adhesion prevention operation is put into a pause state (S4047), and the adhesion prevention step (S404) is completed.

[0093] Next, while the device remains in a pause state (S405) and the operation display unit 8 is displaying a wait screen, a check is made to see if the pause has been interrupted (S406). If the pause has been interrupted (Yes in S406), the process flow for preventing sticking that is performed by the device while it is paused, as shown in FIG. 4, is terminated.

[0094] On the other hand, if the hibernation is not interrupted and the hibernation state continues (No in S406), a check is made in S4047 to see if a certain amount of time has passed since entering the hibernation state (S407), and if the certain amount of time has not passed (No in S407), the process returns to S405.

[0095] On the other hand, if a certain period of time (for example, 24 hours or 48 hours) has passed since entering the hibernation state in S4047 (Yes in S407), the process returns to S404 and the series of operations from S4041 to S4047 is repeated.

[0096] As explained above, the series of operations for preventing ink solidification explained using Fig. 4 is automatically executed at regular time intervals while the printing operation using the print head 2 remains in a pause state. This makes it possible to prevent ink from solidifying in the solenoid valves inside the main body 1 and inside the print head 2 even if the printing operation remains in a pause state for a long time, and makes it possible to smoothly start the printing operation even if the print head 2 is operated after a relatively long pause.

[0097] <Adjusting the viscosity of the ink in the main ink container> Next, adjustment of the viscosity of the ink in the main ink container, which is performed with the print head 2 attached to the head mounting unit 3, will be described with reference to FIGS.

[0098] When printing is performed for a long time with the print head 2, the ink collected from the gutter 25 accumulates in the main ink container 31, and the viscosity of the ink 68A inside the main ink container 31 changes. In addition, the viscosity of the ink 68A contained in the main ink container 31 may change and deviate from the appropriate range by ejecting the solvent from the print head 2 and collecting it in the main ink container 31 in S4045 of the flow diagram described in FIG. 4, or by replenishing the main ink container 31 with the ink 68C in the auxiliary ink container 32. Furthermore, when the print head is not used for a long time, the solvent volatilizes during that time, and the viscosity of the ink 68A inside the main ink container 31 changes. Therefore, it is necessary to measure the viscosity of the ink 68A contained in the main ink container 31, and if the viscosity of the ink 68A deviates from the appropriate range, it is necessary to adjust the viscosity of the ink 68A so that it falls within the appropriate range.

[0099] 8 shows a process flow for adjusting the viscosity of the ink 68A contained in the main ink container 31. First, a guidance (not shown) regarding viscosity adjustment is displayed on the operation display unit 8 (S801).

[0100] Next, it is determined whether the amount of liquid contained inside the collection container 4 attached to the head mounting unit 3 is greater than a predetermined amount using the outputs of the magnetic sensor 76A and the magnet 75 (S802). If the amount of liquid inside the collection container 4 is greater than the predetermined amount, the liquid inside the collection container 4 is discarded and then the determination is made again.

[0101] 9, the pump (for supply) 34 and the pump (for recovery) 35 are operated to open the solenoid valve (for supply) 49 and the solenoid valve (for main body circulation) 58 to open the path (for supply) 801, the path (for main body circulation) 808, and the path (for recovery) 812, thereby circulating the ink 68A in the main ink container 31. In addition, the pump (for circulation) 36 is operated and the solenoid valve (for viscosity measurement) 57 is opened to open the path (for viscosity measurement) 824 and the path (for head circulation) 822, thereby passing the ink 68A contained in the main ink container 31 through the viscosity measuring device 45 and measuring the viscosity of the ink 68A (S803).

[0102] The viscosity of the ink 68A is measured in the same manner as that described in step S4044 of the process flow diagram of FIG.

[0103] The result of the viscosity measurement in S803 is judged (S8031), and if it is judged that the viscosity of the ink 68A is within the appropriate range (Yes in S8031), the ink viscosity adjustment step ends.

[0104] On the other hand, if it is determined in S8031 that the viscosity of the ink 68A is higher than the appropriate range ("high" in S8031), the process proceeds to step S810. On the other hand, if it is determined that the viscosity of the ink 68A is lower than the appropriate range ("low" in S8031), the process proceeds to step S830.

[0105] <<Adjustment for high ink viscosity>> If it is determined in S8031 of FIG. 8 that the viscosity of the ink 68A contained in the main ink container 31 is higher than the appropriate range, steps from S810 onwards are executed to adjust the ink viscosity so that the high ink viscosity falls within the appropriate value range.

[0106] First, in step S810, in order to start ejecting ink from the print head 2, the state in Fig. 9 is switched to the state in Fig. 10. That is, the solenoid valve (for viscosity measurement) 57 is closed to stop the operation of the pump (for circulation) 36, and the passage of ink 68A through the viscosity meter 45 is stopped. Also, the solenoid valve 58 is closed to stop the circulation of ink 68A in the main ink container 31. Next, with pump (for supply) 34 and pump (for recovery) 35 operating, solenoid valve (for switching) 26 is opened to open paths (for supply) 801, 802, and 803 to supply ink 68A from the main ink container 31 to the print head 2, and ink ejection from the nozzle 21 begins (S810), and solenoid valve (for recovery) 50 is opened to open an ink recovery path consisting of path (for recovery) 811 and path (for recovery) 812, so that ink 68A supplied to the print head 2 and ejected from the nozzle 21 is collected in gutter 25 and recovered in the main ink container 31.

[0107] 11, the solenoid valve 50 is closed (S811) to block the ink recovery path formed by path 811 (for recovery) and path 812 (for recovery). As a result, the ink 68A supplied to the print head 2 and ejected from the nozzles 21 overflows from the gutter 25 and is recovered in the recovery container 4 attached to the head mounting unit 3. As a result, the liquid level of the ink 68A contained inside the main ink container 31 continues to decrease.

[0108] As the liquid level of the ink 68A contained inside the main ink container 31 continues to drop, the detection signal of the ink 68A by the liquid level sensor 31B (sensor 2) attached to the main ink container 31 turns OFF (not detected) (Yes in S812). This state is maintained until a predetermined time has elapsed since the detection signal of the liquid level sensor 31B (sensor 2) turned OFF (not detected). As a result, the liquid level of the ink 68A contained inside the main ink container 31 becomes lower than the liquid level detected by the liquid level sensor 31B (sensor 2).

[0109] Here, the predetermined time from when the detection signal of ink 68A by liquid level sensor 31B (sensor 2) turns OFF (non-detection) (Yes in S812) is determined using a conditional formula preset in MPU 301 according to the ink viscosity measured in S803 and the ink temperature measured by a temperature sensor (not shown). If the detected ink viscosity is significantly out of the appropriate range, the predetermined time is set long, and if the deviation of the detected ink viscosity from the appropriate range is relatively small, the predetermined time is set short.

[0110] In this way, by adjusting the amount of ink 68A discarded from the main ink container 31 according to the viscosity of the ink, it is not necessary to discard all of the ink 68A in the main ink container 31 and replace it with new ink even if the viscosity of the ink is higher than the appropriate range, and the amount of ink discarded can be reduced and the ink can be used effectively.

[0111] On the other hand, if the detection signal for ink 68A from the liquid level sensor 31B (sensor 2) attached to the main ink container 31 does not turn OFF (not detected) even after a certain amount of time has passed with ink overflowing from the gutter 25 (if the No state in S812 continues and the preset time has elapsed: Yes in S8121), an abnormality message is output to the operation display unit 8 (S8122), and the solenoid valve 49 is closed to stop the supply of ink to the print head 2.

[0112] After a predetermined time has elapsed since the detection signal for ink 68A by the liquid level sensor 31B (sensor 2) turns OFF (not detected) (Yes in S812), as shown in FIG. 12, the solenoid valve 50 is opened to open the ink recovery path consisting of path (for recovery) 811 and path (for recovery) 812 (S813), and the ink sprayed from the nozzle 21 of the print head 2 and collected in the gutter 25 is recovered into the main ink container 31.

[0113] 12, the pump (for solvent) 37 is operated with the solenoid valve (for solvent supply) 53 open to open the path (for solvent supply) 831 and path (for solvent supply) 833 leading from the solvent container 33 to the main ink container 31. As a result, the solvent 69A stored in the solvent container 33 is supplied to the inside of the main ink container 31 through the paths 831 and 833 (S814). This supply of the solvent 69A to the inside of the main ink container 31 continues until the liquid level sensor 31B (sensor 2) detects that the liquid level of the ink 68A contained in the main ink container 31 has reached the initial level (until Yes is returned in S815).

[0114] When the liquid level sensor 31B (sensor 2) detects that the liquid level of the ink 68A contained in the main ink container 31 has reached the initial level (Yes in S815), the solenoid valve (for solvent supply) 53 is closed to stop the supply of solvent 69A from the solvent container 33 to the main ink container 31, and the pump (for circulation) 36 is operated as shown in FIG. 13, and the solenoid valve (for viscosity measurement) 57 is opened to open the path (for viscosity measurement) 824 and the path (for head circulation) 822, thereby passing the ink 68A contained inside the main ink container 31 through the viscosity meter 45 to measure the viscosity of the ink 68A (S816).

[0115] The method of measuring the viscosity of this ink 68A differs from step S803 and step S4044 in the process flow diagram of Figure 4 in that the ink 68A is supplied from the main ink container 31 to the print head 2, collected in the gutter 25, and collected in the main ink container 31 through paths (for collection) 811 and 812, thereby circulating the ink 68A.

[0116] On the other hand, if the liquid level sensor 31B (sensor 2) does not detect that the liquid level of the ink 68A contained in the main ink container 31 has reached the initial level even after a certain amount of time has passed since the supply of the solvent 69A to the inside of the main ink container 31 began (if the state of No in S815 times out at a preset time: Yes in S8151), an abnormality message is output to the operation display unit 8 (S8122), and the solenoid valve (for solvent supply) 53 is closed to stop the supply of the solvent 69A to the inside of the main ink container 31.

[0117] Next, the viscosity value measured in S816 is judged (S817), and if the measured viscosity value is higher than the set value for judging "ink viscosity is high" that is previously stored in ROM 306 (No in S817), the process returns to S811 and the process for reducing the ink viscosity is repeated.

[0118] On the other hand, if the measured viscosity value is equal to or lower than the set value for judging that "ink viscosity is high" which is stored in advance in ROM 306 (Yes in S817), it is judged that the ink viscosity is within the appropriate range, and in response to an instruction from CPU 301, solenoid valve (for supply) 49 in FIG. 13 is closed and pump (for supply) 34 is stopped, thereby stopping the supply of ink 68A to print head 2 and stopping ink ejection from nozzle 21 of print head 2 (S818), and solenoid valve (for viscosity measurement) 57 is closed to stop the supply of ink to viscosity measuring device 45.

[0119] 14, the solenoid valve (for nozzle cleaning) 55 is opened and the pump (for solvent) 37 is operated, so that the solvent 69A is supplied from the solvent container 33 to the nozzle 21 of the print head 2 through a solvent path that leads from the path (for solvent supply) 831 through the path (for nozzle cleaning) 825 to the print head 2. At this time, the solenoid valve (for recovery) 50 and the solenoid valve (for circulation) 59 are opened to allow the path (for head circulation) 821 and the path (for recovery) 811 to communicate from the print head 2 to the main ink container 31, so that the solvent 69A supplied to the print head 2 is recovered in the main ink container 31 through the path (for head circulation) 821 and the path (for recovery) 811. As a result, the ink 68A remaining in the path (for head circulation) 821, the path (for recovery) 811, the nozzle 21, and the gutter 25 is washed away, and the circulation path is cleaned (S819).

[0120] After the circulation path is cleaned for a predetermined time in S819, the solenoid valve (for recovery) 50, solenoid valve (for nozzle cleaning) 55, and solenoid valve (for circulation) 59 are closed to stop the pump (for recovery) 35 and the pump (for circulation) 36, and while the pump (for solvent) 37 is kept operating, the solenoid valve (for head cleaning) 56 is opened as shown in FIG. 15 to spray the solvent from the cleaning nozzle 72 onto the head mounting unit 3 to which the print head 2 is attached, spraying the solvent from the outside of the print head 2. This performs thorough head cleaning (S820) of the print head 2, which takes longer than normal cleaning and uses a larger amount of solvent 69A. This makes it possible to remove dirt from the print head 2 that was caused by ink overflowing from the gutter 25 in S811.

[0121] After spraying of the solvent has stopped, the pump (for drying) 60 is operated to blow air onto the print head 2 from a supply nozzle 73 having an air outlet, and the pump (for suction) 61 is operated to exhaust the air from inside the head mounting unit 3, thereby drying the print head 2 wetted with the solvent 69A and completing the thorough head cleaning process.

[0122] After the thorough head cleaning is performed, the system enters a pause state (S821), the ink viscosity normalization process is completed, and the initial ink viscosity value (value measured in S803) and the viscosity adjusted value (value measured in S816) are displayed in the ink viscosity display area 80 of the operation and display unit 8 as shown in FIG. 17. However, the information displayed in the ink viscosity display area 80 may be information related to the ink viscosity (e.g., "Viscosity is high. Adjustment required," "Viscosity is within appropriate range," etc.) instead of the ink viscosity value itself. In addition, although not shown in FIG. 17, information regarding the date and time when the viscosity adjustment was performed, and further information regarding the date and time when the viscosity adjustment was performed last time may also be displayed in the ink viscosity display area 80 of the operation and display unit 8. The thorough head cleaning process of S820 may be omitted.

[0123] <<Adjustment when ink viscosity is low>> In S8031 of FIG. 8, if it is determined that the viscosity of the ink 68A contained in the main ink container 31 is lower than the appropriate range, the steps from S830 onwards are executed to adjust the ink viscosity so that the low ink viscosity falls within the appropriate value range.

[0124] First, in step S830, in order to start ejecting ink from the print head 2, the state in Fig. 9 is switched to the state in Fig. 10. That is, the solenoid valve (for viscosity measurement) 57 is closed to stop the operation of the pump (for circulation) 36, and the passage of ink 68A through the viscosity meter 45 is stopped. Also, the solenoid valve 58 is closed to stop the circulation of ink 68A in the main ink container 31.

[0125] Next, with pump (for supply) 34 and pump (for recovery) 35 operating, solenoid valve (for switching) 26 is opened to open paths (for supply) 801, 802, and 803 to supply ink 68A from the main ink container 31 to the print head 2, commencing ink ejection from the nozzle 21, and solenoid valve (for recovery) 50 is opened to open an ink recovery path consisting of path (for recovery) 811 and path (for recovery) 812, so that ink 68A supplied to the print head 2 and ejected from the nozzle 21 is collected in gutter 25 and recovered in the main ink container 31.

[0126] By continuing the state shown in Figure 10, that is, by supplying ink 68A from the main ink container 31 to the print head 2, ejecting it from the nozzles 21, collecting it in the gutter 25, and recovering it in the main ink container 31 through the ink recovery path, the solvent contained in the ink 68A is volatilized and the ink is concentrated (S831).

[0127] The amount of ink 68A collected in the gutter 25 and recovered in the main ink container 31 through the ink recovery path relative to the amount of ink 68A supplied from the main ink container 31 to the print head 2 decreases by the amount of solvent volatilized, and the liquid level of the ink 68A contained inside the main ink container 31 continues to decrease.

[0128] As the liquid level of the ink 68A inside the main ink container 31 continues to drop, the detection signal of the ink 68A by the liquid level sensor 31B (sensor 2) attached to the main ink container 31 turns OFF (not detected) (Yes in S832). This state is maintained until a predetermined time has elapsed since the detection signal of the liquid level sensor 31B (sensor 2) turned OFF (not detected). As a result, the liquid level of the ink 68A contained inside the main ink container 31 becomes lower than the liquid level detected by the liquid level sensor 31B (sensor 2).

[0129] Here, the predetermined time from when the detection signal of ink 68A by liquid level sensor 31B (sensor 2) turns OFF (non-detection) (Yes in S832) is determined using a conditional formula preset in MPU 301 according to the ink viscosity measured in S803 and the ink temperature measured by a temperature sensor (not shown). If the detected ink viscosity is significantly out of the appropriate range, the predetermined time is set long, and if the deviation of the detected ink viscosity from the appropriate range is relatively small, the predetermined time is set short.

[0130] In this way, by adjusting the amount of solvent vaporized from ink 68A according to the viscosity of the ink, it is no longer necessary to discard all of the ink 68A in the main ink container 31 and replace it with new ink even if the viscosity of the ink is lower than the appropriate range, and the amount of ink discarded can be reduced and the ink can be used effectively.

[0131] On the other hand, if the detection signal for ink 68A by the liquid level sensor 31B (sensor 2) attached to the main ink container 31 does not turn OFF (not detected) even after a certain period of time has elapsed since ink 68A was supplied from the main ink container 31 to the print head 2, ejected from the nozzle 21, collected in the gutter 25, and recovered in the main ink container 31 through the ink recovery path (if the No state continues in S832 and the preset time has elapsed: Yes in S8321), an abnormality message is output to the operation display unit 8 (S8322), and the solenoid valve 49 is closed to stop the supply of ink to the print head 2.

[0132] After a predetermined time has elapsed since the detection signal of the ink 68A by the liquid level sensor 31B (sensor 2) has turned OFF (not detected) (Yes in S832), the solenoid valve (for supply) 49 is closed and the solenoid valve (for ink supply) 54 is opened as shown in FIG. 16. This stops the supply of the ink 68A from the main ink container 31 to the print head 2, and the ink 68C contained in the auxiliary ink container 32 is supplied to the print head 2 through a path consisting of the path (for supply) 806 and the paths (for supply) 802 and 803, and is ejected from the nozzle 21. The ink 68C ejected from the nozzle 21 is collected by the gutter 25 and collected in the main ink container 31 through the ink recovery path. This causes the ink 68C contained in the auxiliary ink container 32 to be replenished to the main ink container 31 (S833).

[0133] This supply of ink 68C from the auxiliary ink container 32 to the main ink container 31 continues until the liquid level sensor 31B (sensor 2) detects that the liquid level of the ink 68A contained in the main ink container 31 has reached the initial level (until S834 returns Yes).

[0134] When the liquid level sensor 31B (sensor 2) detects that the liquid level of the ink 68A contained in the main ink container 31 has reached the initial level (Yes in S834), the pump (for circulation) 36 is operated as shown in FIG. 16, and the solenoid valve (for viscosity measurement) 57 is opened to open the path (for viscosity measurement) 824 and the path (for head circulation) 822, thereby passing the ink 68A contained inside the main ink container 31 through the viscosity meter 45 and measuring the viscosity of the ink 68A (S835).

[0135] The method of measuring the viscosity of this ink 68A differs from step S803 and step S4044 in the process flow diagram of Figure 4 in that ink 68C is supplied from the auxiliary ink container 32 to the print head 2, collected in the gutter 25, and collected in the main ink container 31 through paths (for recovery) 811 and 812, while ink 68C is being supplied from the auxiliary ink container 32 to the main ink container 31.

[0136] On the other hand, if the liquid level sensor 31B (sensor 2) does not detect that the liquid level of the ink 68A contained in the main ink container 31 has reached the initial level even after a certain amount of time has elapsed since the supply of ink 68C into the main ink container 31 began (if the No state in S834 expires at a preset time: Yes in S8341), an abnormality message is output to the operation display unit 8 (S8322), and the solenoid valve (for ink supply) 54 is closed to stop the supply of ink 68C from the auxiliary ink container 32 to the main ink container 31.

[0137] Next, the viscosity value measured in S835 is judged (S836), and if the measured viscosity value is lower than the set value for judging "ink viscosity is low" that is previously stored in ROM 306 (No in S836), the process returns to S831 and the process for increasing the ink viscosity is repeated.

[0138] On the other hand, if the measured viscosity value is equal to or higher than the set value for determining that the ink viscosity is low, which is stored in advance in ROM 306 (Yes in S836), it is determined that the ink viscosity is within the appropriate range, and in response to an instruction from CPU 301, solenoid valve (for ink refill) 54 in FIG. 16 is closed and pump (for supply) 34 is stopped, thereby stopping the supply of ink 68C to print head 2 and stopping ink ejection from nozzle 21 of print head 2 (S837), and solenoid valve (for viscosity measurement) 57 is closed to stop the supply of ink to viscosity measuring device 45.

[0139] 14, the solenoid valve (for nozzle cleaning) 55 is opened and the pump (for solvent) 37 is operated, so that the solvent 69A is supplied from the solvent container 33 to the nozzle 21 of the print head 2 through a solvent path that leads from the path (for solvent supply) 831 through the path (for nozzle cleaning) 825 to the print head 2. At this time, the solenoid valve (for recovery) 50 and the solenoid valve (for circulation) 59 are opened to allow the path (for head circulation) 821 and the path (for recovery) 811 to communicate from the print head 2 to the main ink container 31, so that the solvent 69A supplied to the print head 2 is recovered in the main ink container 31 through the path (for head circulation) 821 and the path (for recovery) 811. As a result, the ink 68A remaining in the path (for head circulation) 821, the path (for recovery) 811, the nozzle 21, and the gutter 25 is washed away, and the circulation path is cleaned (S838).

[0140] After cleaning of the circulation path, the system enters a pause state (S839), the ink viscosity normalization process ends, and, as shown in Fig. 17, the initial ink viscosity value (the value measured in S803) and the value after viscosity adjustment (the value measured in S835) are displayed in the ink viscosity display area 80 of the operation and display unit 8. However, the information displayed in the ink viscosity display area 80 may be information related to the ink viscosity (for example, "Viscosity is low. Adjustment required" or "Viscosity is within appropriate range"), rather than the ink viscosity value itself. Although not shown in Fig. 17, information regarding the date and time when the viscosity adjustment was performed, and further information regarding the date and time when the viscosity adjustment was performed last time, may also be displayed in the ink viscosity display area 80 of the operation and display unit 8.

[0141] <Effects of this embodiment> According to this embodiment, when the inkjet recording device remains idle for a long period of time, solvent is sprayed from the print head and recovered from the gutter at regular intervals from the start of the idle period, and the ink is circulated inside the device body. Therefore, even when the inkjet recording device remains idle for a long period of time, it is possible to prevent ink from adhering to solenoid valves, etc.

[0142] Furthermore, according to this embodiment, the viscosity of the ink is measured, and if the viscosity is outside a predetermined range, the viscosity is automatically adjusted depending on whether the viscosity is high or low. Therefore, during printing, the ink can be supplied to the head with the viscosity always maintained within an appropriate range.

[0143] In particular, if the viscosity of the ink becomes higher than the specified range, the viscosity of the ink can be adjusted to an appropriate range simply by discarding a portion of the ink contained in the main ink container, eliminating the need to discard all of the ink in the main ink container and replace it with new ink, thereby reducing the amount of ink discarded and increasing the effective amount of ink used. [Explanation of symbols]

[0144] 1...Main body, 2...Print head, 3...Head mounting unit, 4...Collection container, 5...Cable (for print head), 6...Cable (for head mounting unit), 7...Control unit, 8...Operation display unit, 11...Belt conveyor, 12A...Printing object, 12B...Printing object, 13...Print head fixing bracket, 15...Display unit, 16...Head base, 17...Protective cover, 18...Start button, 19...Stop button, 20...Heater, 21...Nozzle, 23...Charging electrode, 24...Deflection electrode, 24A...Positive electrode, 24B...Ground electrode, 25...Gutter, 26...Solenoid valve (for switching), 27...Filter, 31...Main ink container, 31A,B,C...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...pressure sensor, 39...filter (for supply), 40...filter (for recovery), 41...filter (for nozzle cleaning), 43...filter (for head cleaning), 45...viscosity meter, 46...pressure regulating valve, 48...charge sensor, 49...solenoid valve (for supply), 50...solenoid valve (for recovery), 53...solenoid valve (for solvent supply), 54...solenoid valve (for ink supply), 55...solenoid valve (for nozzle) 56...Solenoid valve (for head cleaning), 57...Solenoid valve (for viscosity measurement), 58...Solenoid valve (for circulation in main body), 59...Solenoid valve (for circulation), 60...Pump (for drying), 61...Pump (for suction), 62...Exhaust duct connection, 68A...Ink, 68B...Ink particles, 68B1...Ink particles, 68C...Ink, 69A...Solvent, 70...Liquid, 74...Float, 75...Magnet, 76A,B...magnetic sensor, 81A...head mounting part, 91...fixing part, 92...fixing jig (for conveyor), 93...joint part, 301...MPU, 302...bus line, 306...ROM, 307...RAM, 311...viscosity measurement circuit, 312...pressure detection circuit, 313...liquid level detection circuit, 314...pump control circuit, 315...solenoid valve drive circuit, 321...pump control circuit, 322...collection container sensor detection circuit, 323...print head detection circuit, 324...head mounting unit detection circuit, 331...excitation voltage generation circuit, 332...deflection voltage generation circuit, 341...phase search charge signal generation circuit, 342...print charge signal generation circuit, 343...D / A converter , 344 ... amplifier circuit, 351 ... phase determination circuit, 352 ... A / D converter, 353 ... amplifier circuit, 600 ... inkjet recording device, 801 to 803 ... path (for supply), 806 ... path (for supply), 808 ... path (for circulation in the main body), 811, 812 ... path (for recovery), 814 ... path (for exhaust), 821, 822 ... path (for head circulation), 824 ... path (for viscosity measurement), 825 ... path (for nozzle cleaning), 831 ... path (for solvent supply), 833 ... path (for solvent supply), 837 ... path (for head cleaning), 841 ... path (for air supply), 843 ... path (for air suction), 901 to 903 ... junction path, 921 ... branch path.

Claims

1. a print head that includes a nozzle for ejecting ink and prints on a print target; a main body including: an ink container which contains the ink to be supplied to the print head; an auxiliary ink container which supplies the ink to the ink container; a solvent container which contains a solvent; a supply path which has a supply pump which supplies the ink from the ink container to the print head; a circulation path which has a circulation pump which returns a portion of the ink supplied to the print head to the ink container; a recovery path which has a recovery pump which sucks the ink ejected from the nozzles of the print head and recovers it in the ink container; and a viscosity measuring unit which measures the viscosity of the ink contained in the ink container; a head mounting unit for mounting the print head; A control unit that controls the print head and the main body; In an inkjet recording apparatus comprising: the control unit controls the print head and the main body when the viscosity of the ink measured by the viscosity measuring unit is outside a preset range so that the viscosity of the ink falls within the preset range, Furthermore, when the viscosity of the ink measured by the viscosity measuring unit is higher than the predetermined range set in advance, the control unit controls the print head and the main body to, with the print head mounted on the head mounting unit, discard a portion of the ink contained in the ink container from the print head to the inside of the head mounting unit via the supply path, and supply the solvent contained in the solvent container to the ink container, thereby reducing the viscosity of the ink contained in the ink container.

2. In the inkjet recording apparatus according to claim 1, An inkjet recording device characterized in that, when the viscosity of the ink measured by the viscosity measuring unit is higher than the predetermined range and the ink contained in the ink container is discarded from the print head, the control unit changes the amount by which the liquid level of the ink contained in the ink container becomes lower than the reference level of the ink preset in the ink container by discarding the ink from the print head, in accordance with the viscosity of the ink measured by the viscosity measuring unit.

3. In the inkjet recording apparatus according to claim 2, an ink jet recording apparatus, comprising: a first ink supply unit that supplies ink to the inkjet recording head; a second ink supply unit that supplies ink to the inkjet recording head;

4. In the inkjet recording apparatus according to claim 1, An inkjet recording device characterized in that, when the viscosity of the ink measured by the viscosity measuring unit is lower than the predetermined range set in advance, the control unit controls the print head and the main body to increase the viscosity of the ink contained inside the ink container by supplying ink from the auxiliary ink container to the ink container via the print head.

5. In the inkjet recording apparatus according to claim 1, The main body further comprises an operation display unit, and after the control unit controls the main body so that the viscosity of the ink falls within the specified range, information regarding the viscosity of the ink is displayed on the operation display unit.

6. In the inkjet recording apparatus according to claim 5, An inkjet recording device characterized in that the information regarding the viscosity of the ink displayed on the operation display unit includes information regarding the viscosity of the ink when the viscosity of the ink is outside the predetermined range before the control unit controls the main body to adjust the viscosity of the ink, and information regarding the viscosity of the ink after the control unit controls the main body and the viscosity of the ink falls within the predetermined range.

7. In the inkjet recording apparatus according to claim 1, an inkjet recording device comprising: a control unit that controls the print head and the main body while ejecting the ink from the print head so that the viscosity of the ink measured by the viscosity measuring unit falls outside the predetermined range, the control unit controlling the print head and the main body so that the viscosity of the ink falls within the predetermined range, and a control unit that stops ejecting the ink from the print head after the viscosity of the ink falls within the predetermined range, and a control unit that supplies the solvent from the solvent container to clean the circulation path.

8. In the inkjet recording apparatus according to claim 1, an inkjet recording device characterized in that the control unit controls the print head and the main body while the printing on the print object by the print head is paused, to supply the solvent contained in the solvent container to the print head and return it to the ink container through the circulation path and the recovery path, repeatedly performing this at regular intervals while the printing by the print head is paused.

9. In the inkjet recording apparatus according to claim 8, an inkjet recording device comprising: a recovery path including a recovery solenoid valve in addition to the recovery pump; and wherein the control unit, at regular time intervals while the print head is resting from printing on the print subject, energizes the recovery solenoid valve to operate the recovery pump with the recovery solenoid valve open, thereby causing air to flow into the ink container through the recovery path from the print head side, thereby volatilizing the solvent contained in the ink stored in the ink container.

10. A method for managing the viscosity of the ink contained in the ink container in an inkjet recording device comprising: a print head having a nozzle for ejecting ink and for printing on a print target, an ink container for storing the ink to be supplied to the print head, an auxiliary ink container for supplying the ink to the ink container, a solvent container for storing a solvent, a supply path for supplying the ink from the ink container to the print head, a circulation path for returning a portion of the ink supplied to the print head to the ink container, a recovery path for sucking up the ink ejected from the nozzle of the print head and recovering it in the ink container, a main body having a viscosity measuring unit for measuring the viscosity of the ink contained in the ink container, a head mounting unit for mounting the print head, and a control unit for controlling the print head and the main body, When the viscosity of the ink measured by the viscosity measuring unit falls outside a preset range, the control unit controls the print head and the main body to adjust the viscosity of the ink contained in the ink container, A method for managing an inkjet recording device, characterized in that when the viscosity of the ink measured by the viscosity measuring unit is higher than the predetermined range set in advance, the control unit controls the print head and the main body to, with the print head attached to the head mounting unit, discard a portion of the ink contained in the ink container from the print head to the inside of the head mounting unit via the supply path, and supply the solvent contained in the solvent container to the ink container, thereby reducing the viscosity of the ink contained in the ink container.

11. The method for managing an inkjet recording apparatus according to claim 10, A method for managing an inkjet recording device, characterized in that when the viscosity of the ink measured by the viscosity measuring unit is higher than the predetermined range and the ink contained in the ink container is discarded from the print head, the amount by which the liquid level of the ink contained in the ink container falls below the reference level of the ink preset in the ink container by discarding the ink from the print head is changed in accordance with the viscosity of the ink measured by the viscosity measuring unit.

12. The method for managing an inkjet recording apparatus according to claim 10, further comprising the steps of: A method for managing an inkjet recording device, characterized in that when the viscosity of the ink measured by the viscosity measuring unit is lower than the predetermined range set in advance, the control unit controls the print head and the main body to increase the viscosity of the ink contained inside the ink container by supplying ink from the auxiliary ink container to the ink container via the print head.

13. The method for managing an inkjet recording apparatus according to claim 10, further comprising the steps of: a control unit for controlling the print head and the main body at regular time intervals during which the printing by the print head is paused, and supplying the solvent contained in the solvent container to the print head and returning it to the ink container through the circulation path and the recovery path, the control unit repeatedly performing the process at regular time intervals during which the printing by the print head is paused, thereby preventing the ink from solidifying.

14. The method for managing an inkjet recording apparatus according to claim 13, further comprising the steps of: a recovery solenoid valve provided in the recovery path at regular intervals while the print head is resting from printing on the print subject, and a pump provided in the recovery path is operated with the recovery solenoid valve open, thereby causing air to flow into the ink container through the recovery path from the print head side, thereby volatilizing the solvent contained in the ink stored in the ink container, by controlling with the control unit.

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