Inkjet recording system

Abstract

[Problem] To enhance the usability of a recovery container for recovering a solvent after cleaning of a print head and prevent any decrease in the reliability of detecting the solvent level after cleaning. [Solution] An inkjet recording system comprises: an inkjet recording device I that is provided with a print head 1; a cleaning placement unit 200 that is connected to a controller 100 and on which the print head 1 is placed when the print head 1 is cleaned using a solvent; a recovery container 300 that is detachably attached to the cleaning placement unit 200 and recovers the solvent after cleaning; a liquid amount sensor 240 that is provided to the cleaning placement unit 200 and detects when the solvent level has risen to a detection space within the cleaning placement unit 200; and a cleaning operation part 101a that performs an operation for cleaning the print head 1 in a state in which the recovery container 300 is attached to the cleaning placement unit 200, and stops the cleaning operation on the basis of a detection signal outputted by the liquid amount sensor 240.

Description

Inkjet recording system

[0001] The present disclosure relates to an inkjet recording system configured to enable cleaning of the print head using a solvent.

[0002] For example, the inkjet recording device disclosed in Patent Document 1 is called a continuous inkjet printer (CIJP), and includes a print head to which components such as nozzles, deflection electrodes, charging electrodes, and gutters are fixed. When the print head becomes dirty due to ink adhesion, the user places the print head in a cleaning station. At the cleaning station, a cleaning liquid (solvent, etc.) is sprayed onto each component of the print head, either manually or automatically by the user, thereby cleaning each component of the print head. Waste liquid after cleaning is stored in a collection container below the cleaning station. A level detection means is provided within the collection container to detect the liquid level of the waste liquid.

[0003] Japanese Patent Application Laid-Open No. 2021-091169

[0004] By providing a level detection means in the collection container, the spraying of cleaning liquid can be stopped before the waste liquid overflows the collection container, preventing the waste liquid from contaminating the surrounding environment. One possible configuration for providing a level detection means in the collection container is to incorporate the level detection means into the collection container itself. However, this would complicate the collection container configuration, potentially leading to malfunctions and reducing user convenience.

[0005] Therefore, it is conceivable to have a rod-shaped detection electrode protrude from the cleaning station and insert the tip of the detection electrode into the collection container, as disclosed in Patent Document 1. This would eliminate the need to incorporate a level detection means into the collection container itself, thereby simplifying the structure of the collection container.

[0006] However, in a structure in which the detection electrode is inserted into the collection container, for example, when the collection container is removed from the cleaning station to discard the waste liquid, the detection electrode is exposed and is therefore prone to contact with objects. Contact with the detection electrode by an object may result in damage to the detection electrode. If the detection electrode is damaged, it may become impossible to detect the waste liquid level or the accuracy of the liquid level detection may decrease.

[0007] The present disclosure has been made in consideration of such points, and its purpose is to improve the usability of a recovery container for recovering solvent after cleaning a print head, and to prevent a decrease in the reliability of detecting the solvent level after cleaning.

[0008] In order to achieve the above object, an inkjet recording system according to one aspect of the present disclosure comprises: a continuous-type inkjet recording device having a controller; and a print head that is electrically and fluidly connected to the controller via a connection cable and installed externally to the controller; a cleaning mount unit that is communicatively connected to the controller via a wired or wireless signal line and installed externally to the controller, and on which the print head is placed when cleaning the print head with a solvent; a recovery container that is detachably attached to the cleaning mount unit and recovers the solvent after cleaning; and a liquid level detection unit that is provided in the cleaning mount unit and detects the liquid level of the solvent that has risen to a detection space in the cleaning mount unit that communicates with the internal space of the recovery container, and outputs a detection signal to the controller.

[0009] That is, when the print head is placed on the cleaning and placement unit, the cleaning operation unit performs cleaning using a solvent. The cleaned solvent is stored in a collection container attached to the cleaning and placement unit. As the amount of solvent in the collection container increases, the solvent level rises to the detection space within the cleaning and placement unit. The liquid level detection unit detects the liquid level that has risen to the detection space within the cleaning and placement unit and outputs a detection signal. Subsequently, for example, an error message can be displayed to the user based on the detection signal, urging them to replace the collection container. Alternatively, stopping the cleaning operation based on the detection signal can more reliably prevent the post-cleaning solvent from leaking to the outside. For example, when disposing of the solvent in the collection container, the collection container may be removed from the cleaning and placement unit. However, since the liquid level detection unit detects the solvent level that has risen to the detection space within the cleaning and placement unit, the liquid level detection unit can be disposed within the cleaning and placement unit and is not exposed to the outside of the cleaning and placement unit after the collection container is removed. This prevents, for example, an object from coming into contact with the liquid level detection unit, thereby maintaining high detection accuracy by the liquid level detection unit.

[0010] As described above, the level of the solvent that has risen to the detection space in the cleaning placement unit is detected by the level detector and a detection signal is output to the controller, so the level can be detected without incorporating a level detector in the recovery container itself, and the level detector can be hidden when the recovery container is removed from the cleaning placement unit. This simplifies the recovery container, improving usability for the user and preventing a decrease in the reliability of solvent level detection after cleaning.

[0011] FIG. 1 is a diagram illustrating the overall configuration of an inkjet recording system. FIG. 2 is a block diagram illustrating the schematic configuration of an inkjet recording device. FIG. 3 is a diagram illustrating the schematic configuration of a print head. FIG. 4 is a diagram illustrating the paths of ink and solvent in an inkjet recording device. FIG. 5 is a perspective view of a print head viewed from below. FIG. 6 is a flowchart illustrating the basic operation of an inkjet recording device. FIG. 7 is a flowchart illustrating the shutdown process of an inkjet recording device. FIG. 8 is a perspective view showing a state in which a print head is placed on a cleaning mount unit. FIG. 9 is a perspective view of the cleaning mount unit showing the state before the collection container is held by the holder. FIG. 10 is a vertical cross-sectional view of the state shown in FIG. 8. FIG. 11 is a view equivalent to FIG. 10 showing a case in which an O-ring is placed on the tip surface of the opening. FIG. 12 is a vertical cross-sectional view with the collection container removed. FIG. 13 is a view equivalent to FIG. 10 showing the state in which the solvent after cleaning has reached the detection space. FIG. 14 is a simplified block diagram of a controller, print head, and cleaning mount unit. FIG. 15 is a flowchart showing the process leading up to maintenance execution. FIG. 16 is a view corresponding to FIG. 13, showing a state in which the collection container is being removed.

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

[0013] In other words, although this specification describes an industrial inkjet printer as an example of an inkjet recording device, the technology disclosed herein can be applied to general equipment that uses inkjet to propel ink particles onto a workpiece, regardless of whether it is called an inkjet recording device or an industrial inkjet printer.

[0014] Furthermore, in this specification, printing by an inkjet recording device will be described, but "printing" here includes all processing using inkjet technology, such as printing characters and marking figures.

[0015] <Overall Configuration> Fig. 1 is a diagram illustrating the overall configuration of an inkjet recording system S. Fig. 2 is a diagram illustrating the schematic configuration of an inkjet recording apparatus I, and Fig. 3 is a diagram illustrating the schematic configuration of a print head 1 in the inkjet recording apparatus I. Fig. 4 is a diagram illustrating the paths of ink and solvent in the inkjet recording apparatus I. The inkjet recording system S illustrated in Fig. 1 is an automatic printing system that is installed on a conveyor line L in a factory, for example, and is configured to print in order on each workpiece W flowing along the conveyor line L. The conveyor line L can be configured, for example, by a belt conveyor or the like.

[0016] It should be noted that the application of the present disclosure is not limited to automatic printing systems installed on the conveying line L. The present invention can also be applied to printing systems installed on lines other than the conveying line L.

[0017] Specifically, the inkjet recording system S includes an inkjet recording device I that prints by causing particulate ink (ink grains) to land on a workpiece W, an operation terminal 800 and external equipment 900 that are connected to the inkjet recording device I, and a cleaning and mounting unit 200 that is connected to the inkjet recording device I and cleans the print head 1. Note that the operation terminal 800 and the external equipment 900 are not essential.

[0018] 1 to 3 includes a print head 1 that ejects ink droplets from a nozzle 12 and causes the ink droplets to land on a workpiece W, and a controller 100 that supplies control signals, ink, and solvent to the print head 1. The controller 100 controls the trajectory of the ink droplets by supplying a control signal to the print head 1. This adjusts the landing position of the ink droplets on the workpiece W, thereby achieving the desired printing.

[0019] In particular, the inkjet recording apparatus I according to this embodiment is configured as a so-called continuous ink jet printer (CIJP). That is, in order to prevent clogging (particularly clogging of the nozzles 12) caused by ink volatilization, ink is constantly circulating inside the inkjet recording apparatus I as long as the inkjet recording apparatus I is in operation, even when not printing. By adopting the continuous system, quick-drying ink can be used without causing clogging due to ink.

[0020] Furthermore, the inkjet recording apparatus I according to this embodiment is capable of cleaning each part of the print head 1, such as the nozzles 12, by sending a solvent to the print head 1. The solvent used for cleaning (solvent after cleaning) can be recovered as needed and reused to adjust the concentration (viscosity) of the ink.

[0021] To achieve ink circulation, the print head 1 is equipped with nozzles 12 that eject ink or solvent, as well as a gutter 16 that collects the ink or solvent ejected from the nozzles 12 (see FIG. 3). The ink or solvent sent from the controller 100 to the print head 1 is ejected from the nozzles 12 and collected by the gutter 16. The collected ink or solvent is sent back to the controller 100 and reused. By repeating this process, the ink can be circulated.

[0022] The operation terminal 800 has, for example, a central processing unit (CPU) and a storage device, and is connected to the controller 100. The operation terminal 800 sets the processing conditions for printing and functions as a terminal for displaying information related to printing to the user.

[0023] The machining conditions set by the operation terminal 800 are output to the controller 100 and stored in its storage unit 102. In addition to or instead of the storage unit 102 of the controller 100, the operation terminal 800 may store the machining conditions.

[0024] The processing conditions according to this embodiment include not only the content of the character string to be printed, but also conditions and parameters related to the start-up process (hereinafter also referred to as "cleaning settings"), which will be described later.

[0025] The operation terminal 800 can be integrated into the controller 100, for example. In this case, the term "operation terminal" is not used, but rather a term such as "control unit" is used.

[0026] The external device 900 is connected to the controller 100 as necessary. In the example shown in Figures 1 and 2, the external device 900 includes a workpiece detection sensor 901, a conveying speed sensor 902, and a programmable logic controller (PLC) 903.

[0027] Specifically, the workpiece detection sensor 901 detects the presence or absence of the workpiece W on the conveying line L, and outputs a signal (detection signal) indicating the detection result to the controller 100. The detection signal output from the workpiece detection sensor 901 functions as a trigger (print trigger) for starting printing.

[0028] The conveying speed sensor 902 is composed of, for example, a rotary encoder, and is capable of detecting the conveying speed of the workpiece W. The conveying speed sensor 902 outputs a signal (detection signal) indicating the detection result to the controller 100. The controller 100 controls the timing of ejecting ink droplets from the print head 1 based on the detection signal input from the conveying speed sensor 902.

[0029] 2, the PLC 903 is electrically connected to the controller 100. The PLC 903 is used to control the inkjet printing system S in accordance with a predetermined sequence.

[0030] In addition to the devices and equipment described above, the inkjet recording apparatus I can also be connected to devices for operation and control, computers for performing various other processes, storage devices, peripheral devices, and the like. In this case, the connection may be, for example, a serial connection such as IEEE 1394, RS-232, RS-422, or USB, or a parallel connection. Alternatively, electrical, magnetic, or optical connections via networks such as 10BASE-T, 100BASE-TX, or 1000BASE-T may also be employed. In addition to wired connections, wireless connections using wireless LANs such as IEEE 802, or radio waves, infrared rays, optical communications, and the like such as Bluetooth (registered trademark) may also be employed. Furthermore, storage media used in storage devices for data exchange and saving various settings may include, for example, various memory cards, magnetic disks, magneto-optical disks, semiconductor memories, hard disks, and the like.

[0031] <Controller 100> The controller 100 is configured to electrically control the print head 1 and to be able to supply ink for printing and a solvent for diluting the ink to the print head 1.

[0032] Specifically, the controller 100 according to this embodiment includes, as components related to electrical control, a memory unit 102 that stores the above-mentioned processing conditions, a control unit 101 that controls each part of the controller 100 and the print head 1, an operation display unit 103 that accepts operations by the user and displays information to the user, and a power supply unit 121 that directs power supplied from outside to the control unit 101.

[0033] The controller 100 also includes components related to the supply of ink, etc., such as an ink supply unit 104 that supplies ink to the nozzles 12 of the print head 1, and a solvent supply unit 105 that supplies solvent to the nozzles 12 and the ink supply unit 104.

[0034] The control unit 101 may be configured as a separate unit from the ink supply unit 104 and the solvent supply unit 105. The memory unit 102 may also be configured as a separate unit from the ink supply unit 104 and the solvent supply unit 105. The operation display unit 103 may also be configured as a separate unit from the ink supply unit 104 and the solvent supply unit 105. In these cases, the components can be combined to form the controller 100.

[0035] (Memory unit 102) The memory unit 102 is configured to store processing conditions set via the operation display unit 103 described below or the operation terminal 800, and to output the stored processing conditions to the control unit 101 based on a control signal from outside.

[0036] Specifically, the storage unit 102 is configured using a volatile memory, a non-volatile memory, a hard disk drive (HDD), a solid state drive (SSD), etc., and can temporarily or continuously store information indicating processing conditions. Note that, when the operation terminal 800 is incorporated into the controller 100, the operation terminal 800 may also serve as the storage unit 102.

[0037] (Control unit 101) Based on the processing conditions stored in the memory unit 102, the control unit 101 controls at least the ink supply unit 104 and the solvent supply unit 105 in the controller 100, and the nozzles 12, the charging electrodes 13, and the deflection electrodes 15 in the print head 1. The control unit 101 controls each unit, so that printing on the workpiece W is performed at a predetermined timing.

[0038] Specifically, the control unit 101 has, for example, a CPU, a memory, an input / output bus, etc., and generates a control signal based on a signal indicating information input via the operation display unit 103 or the operation terminal 800 and a signal indicating processing conditions read from the storage unit 102. The control unit 101 outputs the generated control signal to the controller 100 and each unit of the inkjet recording apparatus I, thereby controlling printing on the workpiece W.

[0039] For example, when printing on the workpiece W, the control unit 101 reads the content to be printed on the workpiece W stored in the storage unit 102 and generates a control signal based on the content to be printed. Then, the control unit 101 outputs the control signal to the charging electrode 13, thereby setting the flight direction of the ink particles so as to achieve a landing position corresponding to the content to be printed.

[0040] 1, the operation display unit 103 can be provided in, for example, a housing constituting the controller 100, but it may also be configured separately from the housing and installed in a location different from the housing. The operation display unit 103 includes a display unit 103a that displays various information related to the inkjet recording apparatus I, and an operation unit 103b that includes, for example, a touch-type operation panel, buttons, switches, etc. The display unit 103a is configured, for example, by a liquid crystal display panel or an organic EL display panel, and is controlled by the control unit 101, and is configured to be able to display a user interface, etc., as will be described later.

[0041] When a user operates the operation unit 103b of the operation display unit 103, the operation information is input to the control unit 101, and the control unit 101 can detect what operation has been performed. For example, by operating the operation unit 103b, it is possible to switch the power of the inkjet recording apparatus I on / off, and to input various settings and information. Note that if the operation terminal 800 is incorporated into the controller 100, the operation terminal 800 may also serve as the operation display unit 103. The display unit 103a of the operation display unit 103 is a notification unit that notifies the user of various types of information, and the operation unit 103b is an input unit that allows various types of information to be input.

[0042] This operation and display unit 103 can also set processing conditions for printing, similar to the above-mentioned operation terminal 800. The processing conditions set by the operation and display unit 103 are output to the controller 100 and stored in its memory unit 102. In the following description, it is assumed that the user operates the operation and display unit 103, but the operation terminal 800 can also be used instead of the operation and display unit 103.

[0043] (Ink supply unit 104) The ink supply unit 104 has, as its main components, an ink cartridge 104a that contains refill ink, a main tank 104b to which ink is supplied from the ink cartridge 104a, and an ink distribution channel 104c. The ink cartridge 104a, main tank 104b, and print head 1 are fluidly connected via the ink distribution channel 104c.

[0044] Of these, the ink cartridge 104a is configured to be detachable from the controller 100, and by replacing it, the main tank 104b can be replenished with ink.

[0045] In this way, the inkjet recording apparatus I according to this embodiment is configured as a so-called "cartridge-type" inkjet printer, but is not limited to this configuration. For example, it may be configured to have a tank that can be opened and closed manually, and to replenish the tank with ink.

[0046] The main tank 104b is a container that stores ink to be supplied to the nozzles 12, and is specifically configured to store ink whose concentration (viscosity) has been adjusted with a solvent. To achieve this configuration, a solvent supply path is connected to the path from the ink cartridge 104a to the main tank 104b.

[0047] Furthermore, the ink circulation path 104c is a path for supplying ink to the print head 1 and includes, for example, a path for sending ink to the nozzles 12 and a path for sending ink back from the gutter 16. The path for sending ink to the nozzles 12 connects the ink cartridge 104a, the main tank 104b, and the nozzles 12. The path for sending ink back from the gutter 16 connects the gutter 16 and the main tank 104b. Ink can be circulated between the print head 1 and the controller 100 using these paths.

[0048] As will be described later, the ink flow path 104c is provided with a plurality of electromagnetic valves including a first valve V1 and a plurality of pumps including an ink pump P1. Of these, each electromagnetic valve opens and closes in response to a control signal output from the control unit 101, thereby controlling the flow of ink. Meanwhile, each pump receives a control signal output from the control unit 101 to pump ink, and can control the flow of ink in the same way as the electromagnetic valves.

[0049] (Solvent supply unit 105) The solvent supply unit 105 mainly comprises a solvent cartridge 105a containing replenishment solvent, a conditioning tank 105b storing the solvent used for cleaning, and a solvent flow path 105c. The solvent cartridge 105a, conditioning tank 105b, and print head 1 are fluidly connected via the solvent flow path 105c. The solvent flow path 105c, through which the solvent flows, is made up of multiple paths, some of which are also used as paths for returning ink from the gutter 16.

[0050] The solvent cartridge 105a is configured to be detachable from the controller 100. By replacing the solvent cartridge 105a, the controller 100 can be replenished with solvent. A solvent tank may be provided instead of the solvent cartridge 105a. The solvent supply unit 105 has a function of detecting whether the solvent in the solvent cartridge 105a has run out or whether there is little solvent remaining. The solvent contained in the solvent cartridge 105a is used to adjust the concentration of ink and is also used as a cleaning agent to clean paths through which ink flows.

[0051] The conditioning tank 105b is configured to store the solvent used for cleaning. As described above, the solvent ejected from the nozzles 12 is recovered by the gutter 16, just like the ink. Therefore, the path for returning the ink from the gutter 16 also serves as the path for returning the solvent.

[0052] The solvent flow path 105c also includes paths for supplying the solvent to the print head 1, the main tank 104b, etc., and has, for example, a path for feeding the solvent to the nozzles 12 and a path for returning the solvent from the gutter 16. The path for feeding the solvent to the nozzles 12 connects the solvent cartridge 105a to the nozzles 12. As described above, the path for returning the solvent from the gutter 16 also serves as a path for returning the ink.

[0053] As will be described later, the solvent flow path 105c is provided with a plurality of solenoid valves including a sixteenth valve V16 and a plurality of pumps including a solvent pump P2. Of these, each solenoid valve opens and closes in response to a control signal output from the control unit 101, thereby controlling the flow of the solvent. Meanwhile, each pump receives a control signal output from the control unit 101 to pump the solvent, and can control the flow of the solvent in the same way as the solenoid valves.

[0054] The classification of the solvent flow path 105c and the ink flow path 104c described above is merely a convenient classification made for the sake of simplicity of explanation. The solvent flow path 105c and the ink flow path 104c are essentially inseparable because they are connected to each other or one serves as the other.

[0055] (Power Supply Unit 121) The power supply unit 121 is interposed between the commercial power supply 700 and the control unit 101, and can relay power supplied from the commercial power supply 700 and supply it to the control unit 101.

[0056] (Other Components) The controller 100 is provided with a connection cable 107, which is a bundle of covered electrical wiring for sending and receiving control signals, tubes for sending and receiving ink (specifically, tubes that define the ink flow path 104c), and tubes for sending and receiving solvent (specifically, tubes that define the solvent flow path 105c). This connection cable 107 is flexible, and is connected to the upper end of the print head 1 (see Figure 1). The controller 100 and print head 1 are electrically and fluidically connected via this connection cable 107.

[0057] <Print head 1> The print head 1 is installed outside the controller 100 and is electrically and fluidly connected to the controller 100 via a connection cable. The print head 1 ejects ink as particulate ink droplets, the concentration of which has been adjusted based on the control signal, ink, and solvent supplied from the controller 100. The print head 1 deflects the flight direction of the ejected ink droplets and causes the deflected ink droplets to land on the surface of the workpiece W, thereby printing on the workpiece W.

[0058] Specifically, as shown in Figure 3, the print head 1 according to this embodiment comprises a vibrator 11 that vibrates the ink, a nozzle 12 that ejects the ink that has been vibrated by the vibrator 11, a charging electrode 13 that charges the particulate ink ejected from the nozzle 12, a charge detection sensor 14 that monitors the charged state of the ink, a deflection electrode 15 that deflects the flight direction of the ink charged by the charging electrode 13, and a gutter 16 that collects the ink that has been undeflected by the deflection electrode 15 or the solvent ejected from the nozzle 12.

[0059] The print head 1 includes a housing 10 that houses a vibrator 11, a nozzle 12, a charging electrode 13, a charge detection sensor 14, a deflection electrode 15, and a gutter 16, and defines an ink droplet flight space S1. The print head 1 is capable of ejecting ink droplets deflected by the deflection electrode 15 to the outside of the housing 10 through the flight space S1.

[0060] 5, a discharge port A is formed on the bottom surface of a housing 10 that forms the outer shape of the print head 1. The discharge port A discharges ink deflected by the deflection electrode 15 to the outside. The ink is discharged from the discharge port A downwards through the housing 10.

[0061] 1, during printing, the print head 1 is supported, for example, by a support member 2. When the print head 1 is supported by the support member 2, the print head 1 is positioned so that its ejection port A faces from above the printing surface of the workpiece W. This location is an example of where the print head 1 may be installed when printing using the inkjet recording device I.

[0062] Below, each part of the print head 1 will be explained in order. In the following description, the "up-down direction" refers to a direction along the vertical direction. For example, the top of the paper in Figure 3 corresponds to the "upward direction," and the bottom of the paper in the same figure corresponds to the "downward direction." In other figures, the corresponding direction will also be called the "up-down direction."

[0063] (Vibrator 11) As illustrated in FIG. 3, the vibrator 11 is disposed near the upper end of the flight space S1 of the housing 10. The vibrator 11 according to this embodiment has a built-in device (e.g., a piezoelectric element) for applying vertical vibrations to (exciting) the ink. This vibrator 11 is configured so that ink is supplied via a connection cable 107, and is able to vibrate the ink thus supplied. The ink vibrated by the vibrator 11 is supplied to the nozzle 12. Although not shown in the drawing, the vibrator 11 according to this embodiment is grounded.

[0064] (Nozzle 12) As shown in Figure 3, the nozzle 12 is connected to the lower end of the vibrator 11 and is positioned with its open end (ink ejection port) facing downward. Ink vibrated by the vibrator 11 can be ejected from the open end of the nozzle 12. A suction path 27 is connected to the nozzle 12 and functions as a return path for releasing pressure inside the print head 1, for example, during shutdown (see Figure 4). Solvent can also be sucked from the nozzle 12 through the suction path 27.

[0065] Here, ink ejected from the nozzle 12 without being vibrated by the vibrator 11 flows as a shaft-shaped so-called "ink shaft." On the other hand, vibrated ink is atomized immediately after being ejected from the nozzle 12, becoming so-called "ink droplets." The ink ejected from the nozzle 12 is shaft-shaped immediately after being ejected from the nozzle 12, but becomes particle-shaped as it moves away from the nozzle 12. The position at which it becomes particle-shaped is called the breakpoint. The ink ejected from the nozzle 12 (ink droplets) passes through a charging electrode 13, which will be described later.

[0066] The solvent supplied to clean the print head 1 passes through the vibrator 11 and the nozzle 12 in that order, and is then ejected from the tip of the nozzle 12. The ejected solvent flows axially and passes through the charging electrode 13.

[0067] 3, the charging electrode 13 is made up of a pair of conductive metal plates, and is disposed below the nozzle 12. The pair of metal plates constituting the charging electrode 13 are fixed to the housing 10 with their respective longitudinal directions aligned in the up-down direction and facing each other horizontally. The distance between the pair of metal plates is set to be larger than the particle size of the ink ejected from the nozzle 12, so that the ink ejected from the nozzle 12 passes between the pair of metal plates.

[0068] A potential (positive potential) is applied to the charging electrode 13 according to this embodiment at least when a printing operation is performed. This generates a potential difference between the vibrator 11 and the charging electrode 13, making it possible to charge ink droplets passing through the charging electrode 13. In order to charge each ink droplet, the charging electrode 13 according to this embodiment is disposed near a breakpoint where the ink ejected from the nozzle 12 breaks into particles.

[0069] A pulse potential that can be controlled by the controller 100 is applied to the charging electrode 13. When a relatively high voltage is applied to the charging electrode 13, the amount of charge (magnitude of negative charge) of each ink particle becomes larger compared to when a lower voltage is applied. When each ink particle has a large charge, it is deflected more by the deflection electrode 15 compared to when the charge is small. The controller 100 can control the amount of deflection of the ink particle by adjusting the magnitude of the pulse potential. The ink particle charged by the charging electrode 13 passes by the side of the charge detection sensor 14 and reaches the deflection electrode 15.

[0070] Furthermore, the solvent discharged from the nozzle 12 passes by the side of the charge detection sensor 14 and reaches the deflection electrode 15 without being charged.

[0071] (Charge detection sensor 14) As shown in Fig. 3, the charge detection sensor 14 is disposed below the charging electrode 13. More specifically, the charge detection sensor 14 is disposed below the metal plate that constitutes the charging electrode 13 (the metal plate on the right side of the paper in the example shown in Fig. 3) so as not to intersect with the trajectory of the flying ink particles. By disposing the charge detection sensor 14 in this manner, it is possible to avoid collisions between the ink particles and the charge detection sensor 14.

[0072] Furthermore, the charge detection sensor 14 according to this embodiment is connected to a circuit board provided inside the housing 10. The charge detection sensor 14 can detect the charge state of ink particles passing by its side. The detection result by the charge detection sensor 14 is output to the control unit 101 as a detection signal. Based on this detection signal, the control unit 101 can determine whether each ink particle is appropriately charged.

[0073] 3, the deflection electrode 15 is composed of a pair of conductive metal plates (so-called "opposing electrodes"), and is disposed below the charging electrode 13 and the charge detection sensor 14. The pair of metal plates are fixed to the housing 10 in such a manner that their respective longitudinal directions are aligned substantially vertically and that they face each other horizontally. Ink particles that pass between the pair of metal plates that make up the charging electrode 13 will then pass between the pair of metal plates that make up the deflection electrode 15.

[0074] A voltage that can be controlled by the controller 100 is applied to the deflection electrode 15. This generates a potential difference between the pair of metal plates that make up the deflection electrode 15. This potential difference can deflect the flight direction of the ink particles according to the amount of charge on the ink particles. The flight direction of the ink particles can be deflected along the alignment direction of the pair of metal plates that make up the deflection electrode 15.

[0075] That is, the flight direction of the ink particles can be controlled via the voltages applied to the charging electrode 13 and the deflection electrode 15, respectively. The ink particles whose flight direction is controlled in this way include those deflected by the deflection electrode 15 and those not deflected by the deflection electrode 15 (non-deflected). Of these, the ink particles deflected by the deflection electrode 15 are involved in printing on the workpiece W. The ink particles deflected by the deflection electrode 15 are ejected from an ejection port A provided on the bottom surface of the housing 10 and land on the workpiece W.

[0076] On the other hand, ink particles that are not deflected by the deflection electrode 15 do not participate in printing on the workpiece W. These ink particles, or axial ink that has not been atomized in the first place, reach the gutter 16, as shown by the dashed line in Figure 3. Similarly, the solvent used to clean the nozzles 12, etc. of the print head 1 and that has passed through the deflection electrode 15 also reaches the gutter 16.

[0077] 3, the gutter 16 is configured as a curved pipe with its open end facing upward, and is disposed below the deflection electrode 15. The gutter 16 according to this embodiment can collect ink that is not involved in printing on the workpiece W and the solvent that has passed through the nozzle 12 (specifically, the solvent that has been ejected from the nozzle 12).

[0078] More specifically, in this embodiment, the open end (upstream end) of the gutter 16 and the open end of the nozzle 12 are arranged to face each other, and the open end of the nozzle 12 is located directly above the open end of the gutter 16. By arranging them in this manner, it becomes possible for the fluid that flows vertically from the open end of the nozzle 12 to be received from the open end of the gutter 16.

[0079] The ink or solvent collected by the gutter 16 is returned to the controller 100 via the ink flow path 104c, the solvent flow path 105c, etc., and is stored in the main tank 104b or the conditioning tank 105b.

[0080] In order to provide a detailed explanation of the recovery of ink or solvent by the gutter 16, the configuration of the ink flow path 104c and the solvent flow path 105c will be described below with reference to FIG. 4. Note that the component marked with the symbol F in FIG. 4 is an example of a filter. In the following description, a description of the arrangement, configuration, etc. of the filter F will be omitted.

[0081] <Regarding the ink and solvent paths> As described above, the controller 100 according to this embodiment is equipped with an ink flow path 104c for supplying ink to the print head 1, and a solvent flow path 105c for supplying solvent to the print head 1, the main tank 104b, etc.

[0082] 4, the ink flow path 104c includes, as paths related to the supply of ink to the nozzles 12, a first ink path 21 connecting the ink cartridge 104a and the first branch portion 51, a sixth ink path 26 connecting the first branch portion 51 (more specifically, a portion of the second ink path 22) and the second branch portion 52, an eighth ink path 28 connecting the second branch portion 52 and the main tank 104b, and a fourth ink path 24 connecting the main tank 104b and the nozzles 12. Here, the sixth ink path 26 according to this embodiment is connected to the second branch portion 52 via a fifth ink path 25, which will be described later.

[0083] In addition, the ink flow path 104c has, as a path related to viscosity measurement by the viscometer 53, a second ink path 22 that connects the first branch portion 51 and the main tank 104b and has the viscometer 53 interposed therein, and a third ink path 23 that is provided independently of the second ink path 22 and connects the main tank 104b and the first branch portion 51.

[0084] The ink flow path 104c also has a fifth ink path 25 that connects the gutter 16 and the main tank 104b as a path related to the recovery of ink by the gutter 16.

[0085] Here, the second ink path 22 is provided with a circulation pump P4, an eleventh valve V11, and a viscometer 53, in that order. The fourth ink path 24 is provided with an ink pump P1, a pressure reducing valve, a pressure gauge, and a fourteenth valve V14, in that order. The fifth ink path 25 is provided with a tenth valve V10, a gutter pump P3, and a second branch 52, in that order.

[0086] On the other hand, the solvent flow path 105 c has a first solvent path 31 that connects the solvent cartridge 105 a and the nozzle 12 as a path related to the supply of the solvent to the nozzle 12 .

[0087] In addition, the solvent flow path 105c may have a second solvent path 32 connecting a midpoint in the first solvent path 31 and the first branch portion 51 as a path related to adjusting the concentration (viscosity) of the ink using the solvent contained in the solvent cartridge 105a (a part of the path connecting the solvent cartridge 105a and the main tank 104b).

[0088] In addition, the solvent flow path 105c may have a third solvent path 33 connecting the first branch portion 51 and the conditioning tank 105b as a path related to concentration adjustment using the solvent stored in the conditioning tank 105b (a part of the path connecting the main tank 104b and the conditioning tank 105b).

[0089] The fifth ink path 25, which is exemplified as the ink flow path 104c, is related to the recovery of the solvent by the gutter 16. As mentioned above, the classification of the "ink flow path 104c" and the "solvent flow path 105c" is merely a classification for convenience.

[0090] Here, the first solvent path 31 is provided, in this order, with an optical empty detection mechanism 44, a solvent pump P2, a sixteenth valve V16, and a twelfth valve V12. A cleaning nozzle 19 serving as a solvent spray unit is connected to the first solvent path 31. The cleaning nozzle 19 is a nozzle for spraying solvent onto the vibrator 11, the tip of the nozzle 12, the charging electrode 13, the deflection electrode 15, etc. of the print head 1 to clean them, and is capable of spraying solvent as a cleaning liquid. A fifteenth valve V15 is provided midway from the cleaning nozzle 19 to the first solvent path 31.

[0091] Here, the first branch section 51 has a fifth valve V5 that opens and closes between the third ink path 23 and the second ink path 22, an eighth valve V8 that opens and closes between the first ink path 21 and the second ink path 22, a ninth valve V9 that opens and closes between the third solvent path 33 and the second ink path 22, and a thirteenth valve V13 that opens and closes between the second solvent path 32 and the second ink path.

[0092] The second branch section 52 also has a first valve V1 that opens and closes between the sixth ink path 26 and the eighth ink path 28, a third valve V3 that opens and closes between the sixth ink path 26 and the conditioning tank 105b, and a fourth valve V4 that opens and closes between the sixth ink path 26 and the waste liquid tank (shown as "waste liquid" in Figure 4).

[0093] The control unit 101 can configure a desired flow path within the controller 100 by outputting control signals to valves provided in each path, such as the 11th valve V11, and outputting control signals to each valve that forms the first branch section 51 and the second branch section 52.

[0094] For example, by opening the eighth valve V8 and the first valve V1, it becomes possible to refill the main tank 104b with ink from the ink cartridge 104a. Also, although this is not the original circulation operation, by opening the fifth valve V5 and the eleventh valve V11, it becomes possible to circulate ink between the second ink path 22, the main tank, and the third ink path 23, and measure the viscosity of the ink with the viscometer 53.

[0095] The same applies to paths related to the solvent. For example, by opening the thirteenth valve V13 and the first valve V1, the solvent contained in the solvent cartridge 105a is supplied to the main tank 104b, making it possible to adjust the concentration of the ink stored in the tank. Furthermore, by opening the ninth valve V9 and the first valve V1, the solvent mixed with ink stored in the conditioning tank 105b passes through the third solvent path 33, the first branch 51, the sixth ink path 26, the second branch 52, and the eighth ink path 28 and is supplied to the main tank 104b.

[0096] The controller 100 also has paths related to air circulation. For example, a first exhaust pipe 41 leading to an exhaust port (not shown) is connected to the main tank 104b. Similarly, a second exhaust pipe 42 leading to the exhaust port is connected to the conditioning tank 105b.

[0097] As another example of a path related to air circulation, the controller 100 has a suction path 27 that connects the nozzle 12 and the first branch portion 51. A sixth valve V6 is provided in the suction path 27, and by opening this sixth valve V6 and the aforementioned fifth valve V5, the nozzle 12 can be connected to the atmosphere via the suction path 27, the first branch portion 51, the sixth ink path 26, the second branch portion 52, the eighth ink path 28, the main tank 104b, and the first exhaust pipe 41. This makes it possible to adjust the ejection pressure of ink droplets ejected from the nozzle 12.

[0098] When printing is performed, the fourteenth valve V14 is opened to supply ink from the main tank 104b via the fourth ink path 24. The ink thus supplied is ejected from the nozzle 12 in the form of ink particles.

[0099] Of the ink (ink particles) ejected from the nozzles 12, the ink involved in printing is ejected from the print head 1 as described with reference to Fig. 3. On the other hand, the ink not involved in printing and the solvent used to clean the nozzles 12, etc. are collected in the gutter 16 and sent back to the controller 100 via the fifth ink path 25.

[0100] In this case, the ink to be returned to the main tank 104b is supplied to the main tank 104b from the first branch portion 51 via the sixth ink path 26, the first valve V1 in the second branch portion 52, and the eighth ink path 28. On the other hand, the solvent to be returned to the conditioning tank 105b is supplied to the conditioning tank 105b from the fifth ink path 25 via the third valve V3 in the second branch portion 52.

[0101] The recovery of ink or solvent by the gutter 16 is performed, for example, in association with the start-up process and the shut-down process of the inkjet recording apparatus I. Here, the "start-up process" refers to the process that is executed before printing begins when the inkjet recording apparatus I is powered on. On the other hand, the "shut-down process" refers to the process that is executed before the operation of the inkjet recording apparatus I is stopped when the inkjet recording apparatus I is powered off.

[0102] More specifically, the inkjet recording apparatus I according to this embodiment does not immediately start printing even when the power switch is turned on. Before starting printing, the inkjet recording apparatus I executes a predetermined start-up process. In this start-up process, the print head 1 is cleaned using a solvent, and then ink ejection begins. The ink ejected immediately after the start-up process begins forms the ink axis described above and is collected by the gutter 16.

[0103] Similarly, the inkjet recording apparatus I according to this embodiment does not immediately stop operation when the power switch is turned off. Before stopping operation, the inkjet recording apparatus I performs a predetermined shutdown process, such as nozzle cleaning. In this shutdown process, solvent is ejected from the nozzles 12 to clean and recover any ink remaining in the nozzles. The ink expelled from the nozzles 12 as the solvent is ejected is recovered by the gutter 16, similar to the ink shaft in the startup process.

[0104] In this embodiment, the "power switch" includes not only a physical push button but also switches configured with a touch panel displayed on the operation display unit 103, etc. The OFF operation of the power switch refers not only to the operation of physically pressing a push button, etc., but also to a shutdown operation instructed via the operation terminal 800, the operation display unit 103, etc. The same applies to the ON operation of the power switch.

[0105] The start-up process and the shut-down process of the inkjet recording apparatus I will be described in detail below.

[0106] <Basic Operation of Inkjet Recording Apparatus I> Fig. 6 is a flowchart illustrating the basic operation of the inkjet recording apparatus I. This flowchart illustrates the basic operation of the inkjet recording apparatus I, including the start-up process.

[0107] 6, the power switch of the inkjet recording apparatus I is turned from OFF to ON, and power is supplied to the inkjet recording apparatus I. In step SA2, which follows step SA1, the control unit 101 executes a start-up process. After the start-up process, in step SA3, the control unit 101 prints on the workpiece W by causing ink particles (ink grains) to land on the workpiece W.

[0108] When the printing operation on the workpiece W is started, ink vibrated by the vibrator 11 is ejected from the nozzle 12, as shown in Figure 3. This ink is supplied appropriately from the ink supply unit 104 of the controller 100. The ink ejected from the nozzle 12 starts to be atomized immediately after being ejected, and is charged by the charging electrode 13 at the atomized stage. The ink particles charged by the charging electrode 13 have their charged state detected by the charge detection sensor 14, and then pass through the deflection electrode 15.

[0109] The ink particles, whose flight direction has been deflected by the deflection electrode 15, pass through a flight space S1 within the housing 10 and are ejected to the outside of the print head 1. As shown in Figure 1, the ink particles ejected from the print head 1 land on the surface of the workpiece W to form characters and figures. The landing position of the ink particles is controlled via the charge amount of each ink particle and the voltage applied to the deflection electrode 15.

[0110] As described above, the inkjet recording apparatus I according to this embodiment is configured as a continuous-type inkjet printer, so that when the apparatus is in a printable state after start-up processing (the operating state of the inkjet recording apparatus I), ink continues to be ejected from the nozzles 12 even when printing is not being performed. The ink ejected at this time is not deflected by the deflection electrodes 15 (in other words, it is "non-deflected"). The non-deflected ink does not participate in printing, but is collected by the gutter 16, circulated within the apparatus, and reused.

[0111] Now, consider the case where printing is completed without any problems and inkjet recording apparatus I is normally shut down. Specifically, assume that in step SA3, the power switch of inkjet recording apparatus I is about to be switched from ON to OFF.

[0112] In this case, in step SA4, the control unit 101 executes a shutdown process. This shutdown process is an example of the "cleaning operation" in this embodiment. The cleaning operation is executed by the cleaning operation unit 101a of the control unit 101.

[0113] FIG. 7 is a flowchart illustrating the shutdown process of the inkjet recording apparatus I. This flowchart illustrates the details of step SA4 in FIG. 6. That is, five steps SC1 to SC5 in FIG. 7 constitute step SA4 in FIG. 6. In step SC1, the control unit 101 stops vibrating the ink ejected from the nozzle 12 and stopping the application of voltage to the charging electrode 13 and the deflection electrode 15 (ink atomization, charging, deflection: ON→OFF). This stops the ink atomization, charging, and deflection, and causes a shaft-shaped ink shaft to be ejected from the nozzle 12.

[0114] In step SC2, which follows step SC1, the control unit 101 stops the ink ejection from the ink shaft (stopping ink ejection). Specifically, in step SC2, to stop ink ejection, the control unit 101 closes the fourteenth valve V14. This prevents ink from being ejected from the nozzles 12.

[0115] In step SC3, which follows step SC2, the control unit 101 executes intermittent solvent ejection (intermittent solvent ejection). By ejecting the solvent intermittently, the inkjet recording device I, particularly the nozzles 12 of the print head 1, can be cleaned. Hereinafter, this operation will be referred to as the "intermittent ejection operation." In this operation, the control unit 101 opens the sixteenth valve V16, the twelfth valve (also referred to as the solvent injection valve) V12, the tenth valve V10, and the first valve V1. In this state, the solvent pump P2 and the gutter pump P3 are operated, whereby the solvent contained in the solvent cartridge 105a is ejected from the nozzles 12 via the first solvent path 31 and collected by the gutter 16. The solvent collected by the gutter 16 is returned to the main tank 104b via the fifth ink path 25 and the second branch 52.

[0116] Immediately after the start of this intermittent ejection operation, it is believed that a large amount of ink remains in the fifth ink path 25, so the solvent is sent back to the main tank 104b rather than to the conditioning tank 105b.

[0117] The control unit 101 also closes the twelfth valve V12 and opens the sixth valve V6, causing the solvent remaining in the nozzle 12 to be sucked into the main tank 104b via the suction path 27, the first branch part 51, the sixth ink path 26, the first valve V1, and the eighth ink path 28 due to the negative pressure exerted by the circulation pump P4.

[0118] The twelfth valve V12 may be left open instead of being closed. In this case, while the solvent is being supplied from the solvent cartridge 105a to the nozzle 12, the supplied solvent is directly sucked through the suction path 27. This improves the flow rate of the solvent flowing through the sixth valve V6, enabling more thorough cleaning.

[0119] In step SC4, which follows step SC3, the control unit 101 ejects the solvent from the nozzle 12. The time for ejecting the solvent in step SC4 is, for example, about 30 seconds. By executing step SC4, it is possible to mainly clean the fifth ink path 25 leading to the gutter 16. Hereinafter, this operation will be referred to as the "gutter cleaning operation."

[0120] In step SC5, which follows step SC4, the control unit 101 recovers the solvent from the print head 1. Specifically, in this step, the control unit 101 opens the tenth valve V10 and the third valve V3. In this state, the gutter pump P3 operates, and the solvent remaining in the nozzles 12 is sucked into the conditioning tank 105b via the fifth ink path 25 and the second branch portion 52. By executing step SC5, the solvent used for cleaning can be recovered.

[0121] When the process shown in step SC5 is completed, a return is made, and the control process returns from the control process shown in Fig. 7 to the control process shown in Fig. 6. Then, in step SA5 following step SA4, the power supply to the inkjet recording apparatus I is cut off, and the inkjet recording apparatus I stops its operation.

[0122] <Cleaning placement unit 200> As shown in Figure 1, the cleaning placement unit 200 is a unit that is installed externally to the controller 100. Specifically, the cleaning placement unit 200 is located in a location that is different from the location where the print head 1 is installed when printing is performed by the inkjet recording apparatus I. As shown in Figure 8, the cleaning placement unit 200 is configured so that the print head 1 is placed on it when cleaning the print head 1 using a solvent (cleaning liquid). Liquids other than solvents can also be used during cleaning.

[0123] The controller 100 and the cleaning and mounting unit 200 are connected to enable communication, and this connection may be a connection using a wired signal line or a connection using a wireless signal line. Similarly, the print head 1 and the controller 100 are connected to enable communication, and this connection may be a connection using a wired signal line or a connection using a wireless signal line. One example of these connection types is a signal line that can send and receive signals.

[0124] When the installation location of the print head 1 when printing with the inkjet recording apparatus I is specified as shown in Figure 1, the cleaning and mounting unit 200 is installed in a location separate from that installation location. The cleaning and mounting unit 200 can be installed separate from the controller 100, but it may also be installed in the same location as the controller 100. The cleaning and mounting unit 200 is a unit that cleans the print head 1 while it is mounted thereon, and may also be called, for example, a cleaning station, cleaning dock, cleaning and mounting device, cleaning and mounting unit, etc. The cleaning and mounting unit 200 and the controller 100 may also be integrated.

[0125] 8 and 9, the cleaning mount unit 200 includes a main body 210 and a recovery container 300 for recovering the solvent after cleaning. The main body 210 includes a back plate 211 extending in the vertical direction.

[0126] As shown in FIG. 10 , the back plate 211 is provided with a bottom wall (bottom) 212 extending toward the front and a peripheral wall 213 extending upward from the bottom wall 212. The bottom wall 212 and peripheral wall 213 form a concave shape that opens upward. As shown by the phantom lines in FIG. 10 , the lower side of the print head 1 placed in the correct position is inserted into the peripheral wall 213. In this state, the upper side of the print head 1 protrudes upward from the upper end of the peripheral wall 213. The bottom wall 212 is located below and away from the ejection port A (shown in FIG. 5 ) of the print head 1. The solvent used when cleaning the print head 1 leaks mainly from the ejection port A of the print head 1, but the bottom wall 212 and peripheral wall 213 are designed to catch the solvent leaking from the ejection port A. The bottom wall portion 212 and the peripheral wall portion 213 are shown as separate for the purpose of explanation, but they may also be integrated so that their boundaries are indistinguishable; in short, they need only be formed into a cylindrical shape with a bottom that can accommodate the underside of the print head 1.

[0127] 8 and 10 , a collection container 300 for collecting solvent after cleaning the print head 1 can be removably attached to the bottom wall 212 of the cleaning mount unit 200. The collection container 300 can be made of, for example, a resin container, and can be translucent or have a scale so that the amount of cleaning liquid inside can be determined from the outside. The collection container 300 does not have to be translucent.

[0128] As shown in FIG. 9 , the collection container 300 has a mouth 301 attached to the cleaning placement unit 200 and a reservoir 302 for collecting the collected solvent. Specifically, the cylindrical mouth 301 is provided at the top of the collection container 300. A screw thread 301a is formed on the outer circumferential surface of the mouth 301. A flange 301b is formed below the screw thread 301a on the outer circumferential surface of the mouth 301. An O-ring 301c is disposed above the flange 301b on the outer circumferential surface of the mouth 301. The O-ring 301c is an example of a sealing member interposed between the mouth 301 and the cleaning placement unit 200. The material of the O-ring 301c is not particularly limited, but examples thereof include elastic materials such as rubber and thermoplastic elastomer. The O-ring 301c has an annular shape that fits along the outer circumferential surface of the mouth 301. The cross-sectional shape of the O-ring 301c when cut in the radial direction is circular, but is not limited to this and may be, for example, elliptical or polygonal.

[0129] The reservoir 302 is connected to the lower end of the mouth 301 and molded integrally with the mouth 301. The diameter of the reservoir 302 is set larger than the diameter of the mouth 301, thereby increasing the volume of the reservoir 302, which is the portion that mainly stores the solvent, while reducing the diameter of the mouth 301, which is the portion that connects the collection container 300 to the cleaning mounting unit 200. The vertical dimension of the mouth 301 is set shorter than the vertical dimension of the reservoir 302.

[0130] The shape of the collection container 300 is not limited to the above-described shape, and may be any shape. For example, the diameter of the opening 301 and the diameter of the storage portion 302 may be the same.

[0131] The attachment direction of the collection container 300 is an upward direction, and the collection container 300 can be attached to the cleaning mounting unit 200 by positioning the collection container 300 at a position below and away from the bottom wall portion 212 of the cleaning mounting unit 200 and then moving it upward. On the other hand, the removal direction of the collection container 300 is the opposite direction to the attachment direction, i.e., downward.

[0132] As shown in FIG. 10 , the cleaning mount unit 200 has a tubular portion 212a that forms a flow path R1 extending from the bottom wall portion 212 in the direction (downward) in which the collection container 300 is removed. The outer diameter of the tubular portion 212a is set so that the tubular portion 212a can be inserted into the opening 301 of the collection container 300, and is specifically set smaller than the inner diameter of the opening 301. The inner diameter of the tubular portion 212a is also set large enough to allow the solvent with increased ink concentration (resulting in increased viscosity) to smoothly flow downward after cleaning. Furthermore, as shown in FIG. 10 , the lower end of the tubular portion 212a is inserted into the collection container 300 when the collection container 300 is attached to the cleaning mount unit 200, and reaches below the lower end of the opening 301, i.e., the inside of the storage portion 302.

[0133] A receiving member 214 made of, for example, a conductive metal plate is provided on the upper surface of the bottom wall portion 212. The receiving member 214 is a member that receives ink leaking from the print head 1 and is connected to an equipotential line. Ink leaking from the print head 1 may be charged by the charging electrode 13 or deflection electrode 15. When charged ink comes into contact with the receiving member 214, the charge on the ink can be released, thereby preventing charge accumulation.

[0134] The receiving member 214 is positioned to face the ejection port A of the print head 1. The receiving member 214 is inclined so that it is positioned lower towards the front, allowing the cleaning liquid received by the receiving member 214 to be guided towards the front side of the bottom wall portion 212 and flow towards the upper end opening of the tubular portion 212a.

[0135] A protruding plate portion 214a that protrudes upward is formed at the front end portion and the middle portion in the front-rear direction of the receiving member 214. An opening portion 214b is also formed in the receiving member 214. The protruding plate portion 214a and the opening portion 214b are not essential.

[0136] A mounting tube portion 215 is formed on the lower surface of the bottom wall portion 212 so as to protrude downward. The mounting tube portion 215 has a larger diameter than the tube portion 212a and surrounds the tube portion 212a. The lower end of the mounting tube portion 215 is located higher than the lower end of the tube portion 212a. A screw groove 215a is formed on the inner peripheral surface of the mounting tube portion 215. The screw thread 301a of the collection container 300 is screwed into the screw groove 215a. By screwing the screw thread 301a of the collection container 300 into the screw groove 215a, the collection container 300 can be attached to the bottom wall portion 212 without leaking liquid. When the collection container 300 is attached, the opening 301 is inserted into the mounting tube portion 215, and the lower end of the tube portion 212a is positioned within the collection container 300. The thread groove 215a may be formed continuously over 360° or more in the circumferential direction on the inner peripheral surface of the mounting tube portion 215, or may be formed over a range less than 360°, and for example, the thread 301a of the collection container 300 may be engaged with the thread groove 215a by rotating the collection container 300 half a turn around a vertical line. Similarly, the thread 301a of the collection container 300 may be formed continuously over 360° or more in the circumferential direction, or may be formed over a range less than 360°.

[0137] When the collection container 300 is attached to the cleaning mounting unit 200, it is sealed from the cleaning mounting unit 200. Specifically, an O-ring 301c arranged on the outer peripheral surface of the mouth portion 301 is in close contact with the inner peripheral surface of the mounting cylindrical portion 215, sealing the gap between the outer peripheral surface of the mouth portion 301 and the inner peripheral surface of the mounting cylindrical portion 215. This prevents air from entering or leaving between the outer peripheral surface of the mouth portion 301 and the inner peripheral surface of the mounting cylindrical portion 215, ensuring airtightness. When the O-ring 301c is arranged on the outer peripheral surface of the mouth portion 301, the O-ring 301c is pressed radially by the outer peripheral surface of the mouth portion 301 and the inner peripheral surface of the mounting cylindrical portion 215, causing it to elastically deform and come into close contact with the outer peripheral surface of the mouth portion 301 and the inner peripheral surface of the mounting cylindrical portion 215 over the entire circumference.

[0138] The O-ring 301c may be fixed to the mouth portion 301 or to the mounting cylindrical portion 215. The O-ring 301c may be detachable from the mouth portion 301 and the mounting cylindrical portion 215, in which case the O-ring 301c can be replaced. The O-ring 301c may be interposed between the mouth portion 301 and the cylindrical portion 212a, in which case sealing can be ensured by bringing the O-ring 301c into close contact with the inner circumferential surface of the mouth portion 301 and the outer circumferential surface of the cylindrical portion 212a.

[0139] 11, the O-ring 301c may be disposed on the tip surface of the mouth portion 301 instead of on the outer circumferential surface of the mouth portion 301. In this case, when the collection container 300 is attached to the cleaning mount unit 200, the O-ring 301c is pressed in the vertical direction by the tip surface of the mouth portion 301 and the lower surface of the bottom wall portion 212, causing it to elastically deform and come into close contact with the tip surface of the mouth portion 301 and the lower surface of the bottom wall portion 212 over the entire circumference. In this case as well, the gap between the mouth portion 301 and the cleaning mount unit 200 can be sealed.

[0140] A plurality of O-rings 301c may be provided. When a plurality of O-rings 301c are provided, they may be disposed on both the outer circumferential surface of the mouth portion 301 and the tip surface of the mouth portion 301, or may be disposed at intervals from each other in the vertical direction on the outer circumferential surface of the mouth portion 301. A cylindrical sealing member may be used instead of or in addition to the O-ring 301c. Also, the O-ring 301c may be omitted, and airtightness may be ensured by the engagement of the screw groove 215a with the screw thread 301a.

[0141] As shown in FIG. 9 , the cleaning placement unit 200 includes a container holder 220. The container holder 220 is attached to a portion of the back plate 211 of the main body 210 below the bottom wall 212 so as to be slidable in the vertical direction. The container holder 220 has a pair of left and right engagement protrusions 221, 221 that protrude forward. A gap is formed between the engagement protrusions 221, 221, allowing the mouth 301 of the collection container 300 to be inserted laterally. The left-right separation distance between the engagement protrusions 221, 221 is set shorter than the outer diameter of the flange 301b of the mouth 301. By inserting the mouth 301 of the collection container 300 between the engagement protrusions 221, 221 laterally (in the direction indicated by arrow X in FIG. 9 ), the flange 301b of the mouth 301 can be hooked from above onto the engagement protrusions 221, 221 and held therein.

[0142] The container holder 220 can be switched between a non-attached position shown in Figures 9 and 12 and a fully-attached position shown in Figure 8. The container holder 220 can be stopped from moving downward from the non-attached position by a well-known locking mechanism, stopper, or the like, allowing the user to easily switch it from the non-attached position to the fully-attached position. The cleaning placement unit 200 may also include a biasing member such as a spring that biases the container holder 220 downward.

[0143] The non-attached position is the lowest position of the container holder 220, where the collection container 300 is removed from the cleaning and placement unit 200. In the non-attached position, the mouth 301 of the collection container 300 can be inserted between the engaging protrusions 221, 221, and the mouth 301 inserted between the engaging protrusions 221, 221 can be removed. The container holder 220 can be switched from the non-attached position to the fully-attached position by moving it upward, i.e., vertically. In this fully-attached position, the container holder 220 is at the highest position, and the mouth 301 of the collection container 300 cannot be inserted between the engaging protrusions 221, 221. Because the mouth 301 of the collection container 300 held by the container holder 220 in the fully-attached position is inserted into the mounting tube 215, the collection container 300 cannot be moved laterally.

[0144] After container holder 220 is placed in the attachment position while holding collection container 300, collection container 300 is rotated in a direction in which thread 301a of opening 301 screws into thread groove 215a of mounting tube 215, thereby threading thread 301a into thread groove 215a and attaching collection container 300 to bottom wall 212. In the process of threading thread 301a into thread groove 215a, collection container 300 gradually moves upward, and as collection container 300 moves upward, container holder 220 is pushed upward by collection container 300, and the attachment position is completed.

[0145] Alternatively, a screw thread may be formed on the inner peripheral surface of the mouth portion 301 and a screw groove may be formed on the outer peripheral surface of the mounting cylinder portion 215, so that the mounting cylinder portion 215 can be disposed inside the mouth portion 301. In this case, an O-ring 301c may be interposed between the inner peripheral surface of the mouth portion 301 and the outer peripheral surface of the mounting cylinder portion 215.

[0146] When removing the collection container 300, the collection container 300 is rotated in the opposite direction to that of attachment to separate the mouth portion 301 from the mounting tube portion 215. After that, the container holder 220 is switched to the non-attached position, and the collection container 300 is moved laterally to remove the mouth portion 301 from between the engaging protrusions 221, 221.

[0147] The attachment structure of the collection container 300 is not limited to the above-described structure, and may be, for example, a structure in which the mouth portion 301 of the collection container 300 is press-fitted into the mounting tubular portion 215, or a structure in which the mounting tubular portion 215 is press-fitted into the mouth portion 301. In the case of a structure in which the mounting tubular portion 215 is press-fitted into the mouth portion 301, an O-ring 301c may be interposed between the inner peripheral surface of the mouth portion 301 and the outer peripheral surface of the mounting tubular portion 215. Furthermore, the container holder 220 may be configured to be attached to the collection container 300 and guided by the main body portion 210. Furthermore, the container holder 220 may be omitted.

[0148] 13, after the cleaning solvent is received by the bottom wall portion 212, it flows downward through the flow path R1 (shown in FIG. 10) inside the cylindrical portion 212a, flows into the storage portion 302, and is stored in the storage portion 302. As the amount of solvent stored in the storage portion 302 increases, the flow path R1 inside the cylindrical portion 212a is filled with the solvent. When the flow path R1 inside the cylindrical portion 212a is filled with the solvent, the detection space R2 provided inside the cleaning placement unit 200 is also filled with the solvent.

[0149] That is, a detection space R2 is provided above the bottom wall 212 of the cleaning mount unit 200, which communicates with the internal space of the collection container 300 via a flow path R1 inside the tubular portion 212a. When the collection container 300 is attached to the cleaning mount unit 200, the tip (lower end) of the tubular portion 212a is inserted through the mouth 301 of the collection container 300 and reaches the storage portion 302. When the tip of the tubular portion 212a reaches the storage portion 302 of the collection container 300, the gap between the mouth 301 of the collection container 300 and the cleaning mount unit 200 is sealed. Therefore, even if the liquid level of the solvent stored in the storage portion 302 reaches above the tip of the tubular portion 212a, a residual space R3 is secured inside the collection container 300 above the tip of the tubular portion 212a. The residual space R3 is also provided between the inner circumferential surface of the mouth 301 and the outer circumferential surface of the tubular portion 212a. The remaining space R3 is sealed by the solvent liquid level L1 and the O-ring 301c. In other words, the O-ring 301c is a sealing member that prevents the air remaining in the storage portion 302 from leaking out from anywhere other than the inside of the cylindrical portion 212a.

[0150] The volume of the residual space R3 varies depending on the position of the tip of the tubular portion 212a. Specifically, when the tubular portion 212a is lengthened and the tip of the tubular portion 212a is moved downward, the volume of the residual space R3 increases, whereas when the tubular portion 212a is shortened and the tip of the tubular portion 212a is moved upward, the volume of the residual space R3 decreases. In this embodiment, the tubular portion 212a is inserted a predetermined length into the collection container 300 so that the solvent fills from the interior of the tubular portion 212a to the detection space R2 while maintaining the residual space R3 above the tip of the tubular portion 212a inside the collection container 300.

[0151] The inkjet recording system S includes a liquid amount sensor (liquid level detection unit) 240 that detects the amount of solvent after cleaning. The liquid amount sensor 240 is provided in the cleaning mount unit 200, detects the liquid level of the solvent that has risen to the detection space R2 in the cleaning mount unit 200, and outputs a detection signal to the controller 100.

[0152] The liquid level sensor 240 is attached to the support portion 216 that supports the receiving member 214 and includes two electrodes. The two electrodes that constitute the liquid level sensor 240 protrude downward from the underside of the support portion 216 and reach the detection space R2. These electrodes are located above the upper end of the tubular portion 212a and detect the solvent level above the tubular portion 212a. In this manner, the liquid level sensor 240 is disposed so as not to be exposed to the outside of the cleaning mount unit 200. In other words, since the cleaning mount unit 200 includes the liquid level sensor 240 that is disposed so as not to be exposed to the outside of the cleaning mount unit 200, it is possible to prevent any object from coming into contact with the liquid level sensor 240 when the collection container 300 is removed. Furthermore, since the liquid level sensor 240 is located on the cleaning mount unit 200 side, the user can freely select the size and shape of the collection container 300. For example, even if the size of the collection container 300 increases, this does not affect the liquid volume detection by the liquid volume sensor 240, and even if the shape of the collection container 300 changes, this does not affect the liquid volume detection by the liquid volume sensor 240. The liquid volume sensor 240 may be attached to the peripheral wall 213 of the cleaning placement unit 200.

[0153] The measurement principle of the liquid level sensor 240 utilizes the fact that the solvent containing ink is a conductor, and by measuring the impedance between two electrodes, the liquid level of the solvent that has risen to the detection space R2 can be detected based on the change in impedance. For example, the positions of the lower ends of both electrodes can be set so that they come into contact with the solvent when the solvent level reaches the detection space R2. In this case, a sudden change in the impedance between the two electrodes indicates that the solvent is full, and the liquid level sensor 240 can be used as a sensor to detect the full level. The liquid level sensor 240 is connected to the control unit 101 of the controller 100 and is configured to output a signal to the control unit 101.

[0154] If the pure solvent is non-conductive, a small amount of ink can be ejected from the nozzle 12 before the cleaning operation, ensuring that the solvent in the collection container 300 contains ink. This allows the above-mentioned detection method to be used.

[0155] The configuration of the liquid level sensor 240 is not limited to the above-described configuration, and any sensor may be used as long as it can directly or indirectly acquire the height of the solvent liquid level that has risen to the detection space R2. An example of a sensor that acquires the height of the solvent liquid level is a displacement sensor. The liquid level sensor 240 may also be, for example, a float sensor, a capacitance level sensor, an ultrasonic level sensor, a vibration level sensor, a differential pressure level sensor, an optical level sensor (fiber type, laser type), a guided pulse level sensor, or a radio wave level sensor. The liquid level sensor 240 may also be formed by combining multiple level sensors. Alternatively, the liquid level sensor 240 may be a sensor that estimates the height of the solvent liquid level without directly measuring the height of the solvent liquid level.

[0156] 14 , the cleaning mount unit 200 is provided with a print head lock sensor 234 and a container lock sensor 235. That is, in this embodiment, a print head lock mechanism (not shown) is provided to lock the print head 1 so that it does not move when the print head 1 is placed in the correct position relative to the cleaning mount unit 200, and the print head lock sensor 234 is capable of detecting whether this print head lock mechanism is in an activated state (locked state). In this embodiment, a container lock mechanism (not shown) is also provided to lock the collection container 300 when the collection container 300 is attached to the cleaning mount unit 200, and the container lock sensor 235 is capable of detecting whether this container lock mechanism is in an activated state (locked state). The print head lock sensor 234 and the container lock sensor 235 are connected to the control unit 101, and detection signals from the print head lock sensor 234 and the container lock sensor 235 are output to the control unit 101.

[0157] FIG. 15 is a flowchart showing the process leading up to maintenance execution. This flow is repeatedly executed at a predetermined cycle while the inkjet recording system S is powered on. In step SD1, when the control unit 101 detects that the print head 1 is locked by the print head lock sensor 234, the process proceeds to step SD2. In step SD2, the control unit 101 determines whether the collection container 300 is locked by the container lock sensor 235. If it is determined that the collection container 300 is not locked, the process proceeds to step SD3. In step SD3, the control unit 101 issues a message requesting the user to lock the collection container 300. This message can be displayed on the display unit 103a, for example. Thereafter, the process proceeds to step SD4, where the control unit 101 determines whether the collection container 300 is locked by the container lock sensor 235. If it is determined that the collection container 300 is not locked, the control unit 101 issues a message requesting the user to lock the collection container 300.

[0158] If it is determined in steps SD2 and SD4 that the collection container 300 is locked, the process proceeds to step SD5. In step SD5, the control unit 101 determines whether a detection signal is being output from the liquid level sensor 240. If the determination in step SD5 is YES and a detection signal is being output from the liquid level sensor 240, the process proceeds to step SD6, where the control unit 101 issues a message requesting the user to waste the solvent in the collection container 300. The message can be displayed on the display unit 103a, for example. Thereafter, the process proceeds to step SD6, where the control unit 101 again determines whether a detection signal is being output from the liquid level sensor 240. If the determination in step SD5 is YES, the control unit 101 issues a message requesting the user to waste the solvent in the collection container 300. If the determination in steps SD5 and SD7 is NO, the process proceeds to step SD8, where various maintenance operations are performed. Specifically, the cleaning operation unit 101a operates the solvent pump P2 of the controller 100 and opens the solvent spray valve. This causes the cleaning operation to be performed by spraying solvent toward the print head 1 from the cleaner nozzle 360 ​​shown by phantom lines in Figure 11, for example. In other words, the cleaning operation unit 101a performs the cleaning operation of the print head 1 with the collection container 300 attached to the cleaning mount unit 200.

[0159] During the cleaning operation, the flowchart shown in Figure 15 is repeatedly executed, and when it detects that the print head 1 has been unlocked in step SD1, that the collection container 300 has been unlocked in step SD2, or that a detection signal has been output from the liquid volume sensor 240 in step SD5, the cleaning operation unit 101a stops the cleaning operation.

[0160] For example, if a detection signal is output from the liquid level sensor 240 in step SD7 after steps SD5 and SD6, this means that the liquid level of the solvent after cleaning has risen to the detection space R2 in the cleaning mount unit 200, as shown in Figure 13, making it difficult to further store the solvent. In this case, the cleaning operation unit 101a does not perform the cleaning operation. As long as the detection signal is output from the liquid level sensor 240, the cleaning operation is not performed.

[0161] Furthermore, after the process proceeds to step SD8 and the cleaning operation unit 101a starts the cleaning operation, it is possible that the liquid level of the post-cleaning solvent may rise to the detection space R2 in the cleaning placement unit 200. In this case, the cleaning operation unit 101a receives a detection signal output by the liquid level sensor 240 and stops the cleaning operation based on the detection signal output by the liquid level sensor 240. This makes it possible to prevent the post-cleaning solvent from overflowing. The cleaning operation is stopped while the detection signal is being output from the liquid level sensor 240.

[0162] The cleaning operation unit 101a can also be operated by manual operation. This is called a manual cleaning mode. For example, the controller 100 is provided with a start button (not shown) for starting the cleaning operation, and when the cleaning operation unit 101a detects that this start button has been operated, it starts the above-mentioned cleaning operation. The start button may be a physical button that the user can press, or may be a button configured by an image displayed on the display unit 103a, for example. The operation state of the button displayed on the display unit 103a is detected by the operation unit 103b, and the detection result is acquired by the cleaning operation unit 101a.

[0163] 15 is also executed when the cleaning operation unit 101a is operated manually. When the cleaning operation unit 101a is operated manually, if the liquid level of the post-cleaning solvent rises to the detection space R2 in the cleaning mount unit 200 after the cleaning operation unit 101a starts the cleaning operation, the cleaning operation unit 101a receives a detection signal output by the liquid level sensor 240 and stops the cleaning operation based on the detection signal output by the liquid level sensor 240.

[0164] When the post-cleaning solvent stored in the collection container 300 is to be disposed of, the collection container 300 is rotated in the opposite direction to the rotation direction when the collection container 300 was attached. Rotating the collection container 300 in the opposite direction to the rotation direction when the collection container 300 was attached lowers the collection container 300 in accordance with the pitch of the thread groove 215a. Eventually, the threads 301a of the collection container 300 disengage from the thread groove 215a of the mounting cylindrical portion 215, and the O-ring 301c separates from the inner circumferential surface of the mounting cylindrical portion 215, as shown in FIG. 16 . When the O-ring 301c separates from the inner circumferential surface of the mounting cylindrical portion 215, an air-vent path is formed that opens the residual space R3 to the atmosphere. By opening the residual space R3 to the atmosphere, air within the residual space R3 can flow out as indicated by arrow Y. This allows the solvent present in the detection space R2 in the cleaning placement unit 200 and the solvent present in the flow path R1 inside the cylindrical portion 212a to naturally flow downward by gravity and be stored in the storage portion 302 of the collection container 300. In this embodiment, the atmospheric release path is formed by rotating the collection container 300, but this is not limited to this. The collection container 300 may be pulled downward to displace it or tilted, thereby separating the O-ring 301c from the inner surface of the mounting tube portion 215, thereby forming the atmospheric release path.

[0165] The moment the O-ring 301c separates even slightly from the inner circumferential surface of the mounting cylindrical portion 215, the residual space R3 is opened to the atmosphere. At the same time that the residual space R3 is opened to the atmosphere, the solvent present in the detection space R2 and the solvent present in the flow path R1 inside the cylindrical portion 212a flows downward. When the solvent present in the detection space R2 and the solvent present in the flow path R1 inside the cylindrical portion 212a flows downward to the storage portion 302, the liquid level in the storage portion 302 rises from the liquid level indicated by the symbol L1 to the liquid level indicated by the symbol L2. The liquid level L2 only needs to be located below the upper end of the opening portion 301, and in this embodiment, it is located within the storage portion 302.

[0166] The height of the liquid level L2 after the liquid level sensor 240 outputs a detection signal and the remaining space R3 is opened to the atmosphere varies depending on the internal volume of the tubular portion 212a and the volume of the solvent at the time of detection in the detection space R2. The greater the internal volume of the tubular portion 212a, the higher the height of the liquid level L2. Furthermore, the greater the volume of the solvent at the time of detection in the detection space R2, the higher the height of the liquid level L2. Furthermore, the height of the liquid level L2 varies depending on the inner diameter of the storage portion 302. The larger the inner diameter of the storage portion 302, the lower the height of the liquid level L2.

[0167] In this embodiment, the total amount of solvent present inside the tubular portion 212a and the detection space R2 when the cleaning operation by the cleaning unit 101a is stopped is set to be less than the volume of the remaining space R3. This allows the height of the liquid level L2 to be positioned below the upper end of the opening 301, so that the solvent after cleaning will not overflow from the collection container 300 when the collection container 300 is removed. Also, as described above, the cleaning unit 101a stops the cleaning operation before the total amount of solvent present inside the tubular portion 212a and the detection space R2 becomes equal to or greater than the volume of the remaining space R3, so that the solvent after cleaning will not overflow from the collection container 300 when the collection container 300 is removed.

[0168] The remaining space R3 may be entirely filled with air, or may be filled with air and some other object, or may be filled with some other object only. For example, when the collection container 300 is attached, some other object may be inserted into the remaining space R3 through the opening 301, and some or all of the remaining space R3 may be occupied by the object. An example of such an object is a thick cylindrical portion. In this case, when the collection container 300 is removed, the solvent present in the cylindrical portion flows down the cylindrical portion and reaches the storage portion 302.

[0169] The above-described embodiments are merely examples in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention.

[0170] As described above, the present invention can be used, for example, when printing on various types of workpieces.

[0171] 1 Print head 100 Controller 101a Cleaning operation section 200 Cleaning placement unit 212a Cylinder section 240 Liquid volume sensor (liquid level detection section) 300 Recovery container 301 Mouth section 301c O-ring (sealing member) 302 Storage section I Inkjet recording apparatus S Inkjet recording system R1 Flow path R2 Detection space R3 Residual space

Claims

1. An inkjet recording system comprising: a continuous type inkjet recording device having a controller and a print head electrically and fluidly connected to the controller via a connection cable and installed externally to the controller; a cleaning mount unit communicatively connected to the controller via a wired or wireless signal line and installed externally to the controller, on which the print head is placed when cleaning the print head with a solvent; a recovery container removably attached to the cleaning mount unit for recovering the solvent after cleaning; and a liquid level detection unit provided in the cleaning mount unit for detecting the liquid level of the solvent that has risen to a detection space in the cleaning mount unit that communicates with the internal space of the recovery container and outputting a detection signal to the controller.

2. An inkjet recording system according to claim 1, further comprising a cleaning operation section provided in the controller, which performs a cleaning operation on the print head with the collection container attached to the cleaning placement unit, and which stops the cleaning operation based on the detection signal output by the liquid level detection section.

3. An inkjet recording system according to claim 2, wherein the cleaning placement unit has a tubular portion that forms a flow path extending from the bottom that receives the solvent after cleaning in the direction in which the recovery container is removed, the detection space communicates with the internal space of the recovery container via the inside of the tubular portion, and the liquid level detection portion detects the liquid level of the solvent above the tubular portion.

4. An inkjet recording system according to claim 1, wherein the collection container is sealed between the cleaning mount unit and the collection container when attached to the cleaning mount unit.

5. An inkjet recording system according to claim 3, wherein the recovery container has a mouth portion attached to the cleaning and mounting unit and a storage portion for storing the recovered solvent, and when the recovery container is attached to the cleaning and mounting unit, the tip of the tubular portion is inserted through the mouth portion and reaches the storage portion.

6. An inkjet recording system according to claim 5, further comprising a sealing member for preventing air remaining in said storage portion from leaking out from any place other than the inside of said cylindrical portion to the outside.

7. An inkjet recording system according to claim 6, wherein the sealing member is interposed between the opening and the cleaning and placing unit.

8. An inkjet recording system according to claim 7, wherein the sealing member is an O-ring disposed on at least one of the outer circumferential surface and the tip surface of the mouth portion.

9. An inkjet recording system according to claim 3, wherein the tubular portion is configured to be inserted a predetermined length into the collection container so that the solvent fills from the inside of the tubular portion up to the detection space, while leaving a residual space inside the collection container above the tip of the tubular portion.

10. An inkjet recording system as described in claim 9, wherein the total amount of solvent present inside the cylindrical portion and in the detection space when the cleaning operation by the cleaning operation unit is stopped is set to be less than the volume of the remaining space.

11. An inkjet recording system according to claim 9, wherein the cleaning operation unit stops the cleaning operation before the total amount of solvent present inside the cylindrical portion and in the detection space becomes equal to or greater than the volume of the remaining space.

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