Inkjet recording device and inkjet recording system

Abstract

In this inkjet recording device of a continuous type, solvent consumption in head cleaning is reduced, and convenience of the inkjet recording device is improved. An inkjet recording device (I) of a continuous type is provided with: a printing head (1) that accommodates therein a nozzle (12), a charging electrode (13), a deflection electrode (15), and a gutter (16); an ink supply unit (104) that supplies ink to the printing head (1); a solvent supply unit (105) that supplies a solvent to the printing head (1); and a control unit (101) that controls the supply of the ink from the ink supply unit (104) to the printing head (1) and controls the supply of the solvent from the solvent supply unit (105) to the printing head (1). The printing head (1) has an assist unit (18) that assists cleaning when cleaning the components accommodated in the printing head (1) by using the solvent supplied from the solvent supply unit (105).

Description

Inkjet recording apparatus and inkjet recording system

[0001] The present disclosure relates to a continuous inkjet recording apparatus and an inkjet recording system including the inkjet recording apparatus.

[0002] An example of a continuous inkjet recording device is disclosed in Patent Document 1. Specifically, Patent Document 1 discloses an inkjet recording system that includes a print head that houses various components, and a cleaning mount on which the print head is placed when cleaning the print head with a solvent.

[0003] Japanese Patent Application Laid-Open No. 2021-091181

[0004] In a typical continuous inkjet recording device, ink droplets continue to fly through the internal space of the print head. As a result, dirt easily accumulates inside the print head. The inside of the print head must be cleaned periodically.

[0005] Until now, print head cleaning (head cleaning) has been performed by users themselves spraying solvent into the print head, or by placing the print head on a cleaning loading section as described in Patent Document 1 and then automatically ejecting solvent from a cleaning nozzle located inside the print head.

[0006] However, if a large amount of dirt accumulates inside the print head after long-term use, whether the user cleans the head themselves or cleans the head using a cleaning nozzle, a large amount of solvent will be consumed.Furthermore, if a large amount of dirt accumulates, it is not easy to remove all of the dirt even if the head is cleaned.

[0007] Therefore, it is considered to wash the head frequently before a large amount of dirt accumulates, that is, before the dirt becomes difficult to remove. However, washing the head frequently increases the number of times the solvent is used, which ultimately results in consuming a large amount of solvent.

[0008] Consuming a large amount of solvent increases the frequency of solvent replenishment, which is inconvenient for improving the convenience of the inkjet recording apparatus.

[0009] The present disclosure has been made in view of the above points, and an object thereof is to reduce the amount of solvent consumed in head cleaning and to improve the convenience of inkjet recording apparatuses.

[0010] A first aspect of the present disclosure relates to a continuous inkjet recording device comprising: a print head that houses a nozzle that ejects particulate ink, a charging electrode that charges the particulate ink ejected from the nozzle, a deflection electrode that deflects the flight direction of the ink charged by the charging electrode, and a gutter that collects ink that has been undeflected by the deflection electrode, and that ejects the ink deflected by the deflection electrode to the outside; an ink supply unit that supplies ink to the print head; a solvent supply unit that supplies solvent to the print head; and a control unit that controls the supply of ink from the ink supply unit to the print head and the supply of solvent from the solvent supply unit to the print head, and that performs printing by causing the ink ejected from the print head to land on a print object.

[0011] According to a first aspect of the present disclosure, the print head has an assist unit that assists in cleaning the components housed inside the print head with the solvent supplied from the solvent supply unit.

[0012] According to the first aspect, the amount of solvent consumed in head cleaning can be reduced by having the assist unit assist in head cleaning, thereby improving the convenience of the inkjet recording apparatus.

[0013] Furthermore, according to a second aspect of the present disclosure, the assist unit may include an air injection unit that injects air into the interior of the print head, and may assist the cleaning by directing the air injected from the air injection unit against the solvent supplied from the solvent supply unit.

[0014] According to the second aspect, the solvent supplied from the solvent supply unit can be sprayed onto the components inside the print head by air. By spraying the solvent onto the components, dirt adhering to the components can be easily removed. This makes it possible to achieve a sufficient cleaning effect while reducing the amount of solvent consumed.

[0015] Furthermore, according to a third aspect of the present disclosure, the assist unit may be configured to direct air sprayed from the air spray unit onto the solvent supplied from the solvent supply unit to turn the solvent into mist, thereby expanding the area of ​​the part that is cleaned by the solvent.

[0016] According to the third aspect, the solvent supplied from the solvent supply unit can be converted into mist by air and then sprayed onto the components inside the print head. Converting the solvent into mist contributes to expanding the cleaning area of ​​the components. This makes it possible to achieve sufficient cleaning effectiveness while reducing solvent consumption.

[0017] Furthermore, according to a fourth aspect of the present disclosure, the print head may have an ink ejection port for ejecting ink deflected by the deflection electrode to the outside, and the control unit may have a cleaning management unit that manages the amount of solvent used during cleaning so that an amount of solvent corresponding to the air ejected from the air ejection unit is supplied.

[0018] According to the fourth aspect, the cleaning management unit manages the amount of solvent used, which, combined with the assistance of the assist unit in cleaning, can further reduce the amount of solvent consumed.

[0019] Furthermore, according to a fifth aspect of the present disclosure, the assisting unit may be located inside the print head and have a contact portion that mechanically contacts the component, and assist the cleaning by bringing the contact portion into contact with the component that has been wetted with the solvent supplied from the solvent supply unit.

[0020] According to the fifth aspect, the solvent supplied from the solvent supply unit can be rubbed onto the components inside the print head by the contact unit. Rubbing the solvent onto the components makes it easier to remove dirt adhering to the components. This makes it possible to achieve a sufficient cleaning effect while reducing the amount of solvent consumed.

[0021] Furthermore, according to a sixth aspect of the present disclosure, the assist unit may expand the area of ​​the part that is cleaned by the solvent by bringing the contact portion into contact with the solvent supplied from the solvent supply unit and wiping off the solvent.

[0022] According to the sixth aspect, the solvent supplied from the solvent supply unit can be wiped off from the components inside the print head by the contact unit. Wiping off the solvent contributes to expanding the cleaning area of ​​the components. This makes it possible to achieve sufficient cleaning effectiveness while reducing solvent consumption.

[0023] Furthermore, according to a seventh aspect of the present disclosure, the control unit may have a cleaning management unit that manages the amount of solvent used during cleaning so that the surface of the component is wetted with the solvent supplied from the solvent supply unit.

[0024] According to the seventh aspect, the cleaning management unit manages the amount of solvent used, which, combined with the assistance of the assist unit in cleaning, can further reduce the amount of solvent consumed.

[0025] Furthermore, according to an eighth aspect of the present disclosure, the air injection unit may be arranged to inject air toward the deflection electrode, and to interpose an axial solvent ejected from the nozzle between the air injection unit and the deflection electrode.

[0026] According to the eighth aspect, the solvent supplied from the nozzle can be sprayed onto components inside the print head by air. In the case of a typical continuous inkjet recording device, the amount of solvent discharged from the nozzle can be precisely controlled. Precise control of the amount of solvent discharged contributes to reducing solvent consumption.

[0027] Furthermore, in general, stains caused by ink gradually accumulate on the deflection electrodes as the inkjet recording device is repeatedly used. In contrast, according to the eighth aspect, a solvent can be sprayed onto the deflection electrodes, making it easier to remove stains adhering to the deflection electrodes. This is advantageous in that it reduces the amount of solvent consumed while still providing a sufficient cleaning effect.

[0028] Furthermore, according to a ninth aspect of the present disclosure, the deflection electrode may be composed of first and second electrode plates facing each other, and the air injection unit may be arranged on the first electrode plate so as to inject air toward the second electrode plate.

[0029] According to the ninth aspect, by disposing the air injection unit on the first electrode plate, the air injection unit and the axial solvent can be brought as close as possible to each other, which is advantageous in that the solvent can be sprayed more reliably and a sufficient cleaning effect can be achieved while reducing the amount of solvent consumed.

[0030] According to a tenth aspect of the present disclosure, the first electrode plate may be grounded.

[0031] Generally, a high voltage is applied to the ungrounded second electrode plate, which means that charged ink is attracted to the second electrode plate more than to the grounded first electrode plate, and the second electrode plate is more susceptible to accumulation of dirt than the first electrode plate.

[0032] In contrast, according to the tenth aspect, the air injection unit sprays the solvent toward the second electrode plate when the assist unit provides assistance, thereby making it possible to more reliably clean the second electrode plate, which is expected to be prone to accumulation of dirt.

[0033] Furthermore, according to an eleventh aspect of the present disclosure, the print head may have an ink ejection port for ejecting ink deflected by the deflection electrode to the outside, and the second electrode plate may have an inclined surface inclined in a direction away from the axial solvent, and a bent surface extending from the tip of the inclined surface on the ink ejection port side and bending more steeply than the inclined surface in a direction away from the axial solvent.

[0034] According to the eleventh aspect, by providing a bent surface on the second electrode plate, the flow direction of the air jetted toward the second electrode plate can be guided in a direction away from the axial solvent. This allows the flow direction of the solvent carried by the air flow to also be guided in a direction away from the axial solvent. This suppresses leakage of the solvent from the ink ejection orifices, thereby improving the convenience of the inkjet recording device.

[0035] Furthermore, according to a twelfth aspect of the present disclosure, the inkjet recording device may include a controller that houses the ink supply unit, the solvent supply unit, and the control unit therein, the controller further having an air generation unit that generates air to be sprayed from the air spray unit, and the assist unit may have a control valve for controlling the spray of air generated by the air generation unit.

[0036] According to the twelfth aspect, by arranging the control valve in the print head and the air generating unit in the controller, the print head can be made more compact by removing the air generating unit from the print head, thereby improving the convenience of the inkjet recording device.

[0037] According to a thirteenth aspect of the present disclosure, the air generating unit may include an air dryer in the controller that generates dry air by drying air.

[0038] One way to promote the spraying of solvent with air or to expand the cleaning area by turning the air into mist is to generate higher pressure air. However, if the air is pressurized by the air generator inside the controller, there is a concern that condensation may occur inside the controller.

[0039] In contrast, according to the thirteenth aspect, the air generating unit generates dry air using an air dryer. By configuring the air generating unit to generate dry air, it is possible to suppress the occurrence of condensation even if the air generating unit is disposed inside the controller.

[0040] According to a fourteenth aspect of the present disclosure, the inkjet recording apparatus may further include a pressure sensor that is disposed midway from the air dryer to the assist unit and that detects blockage of air.

[0041] According to the fourteenth aspect, it is possible to detect blockage of dry air after passing through the air dryer, thereby improving the convenience of the inkjet recording apparatus.

[0042] Furthermore, according to a fifteenth aspect of the present disclosure, the print head may have an ink ejection port for ejecting ink deflected by the deflection electrode to the outside, and a shutter for opening and closing the ink ejection port.

[0043] According to the fifteenth aspect, by providing a shutter that opens and closes the ink ejection port, it is possible to suppress leakage of solvent from the ink ejection port, thereby improving the convenience of the ink jet recording apparatus.

[0044] According to a sixteenth aspect of the present disclosure, the control unit may operate the shutter to close the ink ejection opening before assistance is provided by the assist unit.

[0045] According to the sixteenth aspect, by closing the ink ejection port before the assist starts, leakage of the solvent from the ink ejection port can be more reliably suppressed, thereby improving the convenience of the inkjet recording apparatus.

[0046] According to a seventeenth aspect of the present disclosure, the inkjet recording apparatus may further include a drying unit that dries the inside of the print head when the ink ejection ports are closed by the shutter.

[0047] According to the seventeenth aspect, by drying the inside of the print head with the ink ejection ports closed, leakage of solvent from the ink ejection ports can be more reliably suppressed, thereby improving the convenience of the inkjet recording device.

[0048] Furthermore, according to an eighteenth aspect of the present disclosure, the control unit may perform a drying process to dry the inside of the print head by causing the assist unit to perform assistance when solvent is not being supplied from the solvent supply unit.

[0049] According to the eighteenth aspect, the components inside the print head can be dried by blowing air onto the components or by bringing the contact portion into contact with the components when the solvent is not being supplied, thereby improving the convenience of the inkjet recording device.

[0050] Furthermore, according to a nineteenth aspect of the present disclosure, the control unit may be configured to alternately perform a cleaning process in which the parts are cleaned with the solvent supplied from the solvent supply unit and the drying process by causing the assist unit to perform assistance while turning the solvent supply from the solvent supply unit on and off.

[0051] According to the nineteenth aspect, by alternately repeating the cleaning process and the drying process, the head can be cleaned while drying the solvent each time, which makes it possible to more reliably prevent leakage of the solvent and improve the convenience of the inkjet recording apparatus.

[0052] A twentieth aspect of the present disclosure relates to an inkjet recording system. The inkjet recording system includes: a print head that houses nozzles that eject particulate ink, a charging electrode that charges the particulate ink ejected from the nozzles, a deflection electrode that deflects the flight direction of the ink charged by the charging electrode, and a gutter that collects ink that has been undeflected by the deflection electrode, and that ejects the ink deflected by the deflection electrode to the outside, an ink supply unit that supplies ink to the print head, a solvent supply unit that supplies solvent to the print head, and a control unit that controls the supply of ink from the ink supply unit to the print head and the supply of solvent from the solvent supply unit to the print head, and includes: a continuous inkjet recording device that performs printing by causing the ink ejected from the print head to land on a print target; and a cleaning device that is attached to the print head and has an assist unit that assists in cleaning of components housed inside the print head with the solvent supplied from the solvent supply unit.

[0053] According to the twentieth aspect, the amount of solvent consumed in head cleaning can be reduced, and the convenience of the inkjet recording apparatus can be improved.

[0054] According to another aspect of the present disclosure, the inkjet recording device may further include a suction unit that sucks in and exhausts air from an internal space of the print head.

[0055] According to this aspect, by providing a suction unit in the inkjet recording device, it is possible to dry the internal space of the print head and discharge the evaporated solvent, thereby improving the convenience of the inkjet recording device.

[0056] According to another aspect of the present disclosure, the inkjet recording device may further include a posture sensor that detects the posture of the print head, and the control unit may change the cleaning sequence based on a detection signal from the posture sensor.

[0057] According to this aspect, by changing the cleaning sequence depending on the position of the print head, the convenience of the inkjet recording device can be improved.

[0058] According to another aspect of the present disclosure, the parts cleaned with the solvent supplied from the solvent supply section may include at least one of the gutter, the nozzle, and the deflection electrode.

[0059] As described above, according to the present disclosure, it is possible to reduce the amount of solvent consumed in head cleaning and improve the convenience of the inkjet recording apparatus.

[0060] FIG. 1 is a diagram illustrating the overall configuration of an inkjet recording system. FIG. 2 is a block diagram illustrating the general configuration of an inkjet recording apparatus. FIG. 3 is a diagram illustrating the general configuration of a print head. FIG. 4A is a diagram illustrating the general configuration of a print head. FIG. 4B is a diagram illustrating the general configuration of a print head. FIG. 5 is a diagram illustrating ink and solvent paths in an inkjet recording apparatus. FIG. 6 is a diagram illustrating the overall configuration of an assist module. FIG. 7 is a perspective view illustrating the internal structure of a print head. FIG. 8 is a flowchart illustrating a process for determining whether head cleaning is necessary. FIG. 9 is a flowchart illustrating a specific process for head cleaning. FIG. 10A is a diagram corresponding to FIG. 4A and illustrating a first modified inkjet recording system. FIG. 10B is a diagram corresponding to FIG. 4B and illustrating a first modified inkjet recording system. FIG. 11 is a diagram illustrating the internal structure of a print head according to the first modified example. FIG. 12 is a diagram corresponding to FIG. 4A and illustrating a second modified inkjet recording system. Fig. 13A is a diagram illustrating the operation of the assist unit according to the second modified example. Fig. 13B is a diagram illustrating the operation of the assist unit according to the second modified example. Fig. 14 is a diagram corresponding to Fig. 1 showing a third modified example of the inkjet recording system. Fig. 15 is a diagram corresponding to Fig. 4A showing a third modified example of the inkjet recording system. Fig. 16 is a flow path diagram in which elements related to cleaning of the print head 1 are extracted from Fig. 5.

[0061] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that the following description is for illustrative purposes only.

[0062] 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 configured to eject ink particles and land them on a print target such as a workpiece, regardless of whether it is called an inkjet recording device or an industrial inkjet printer.

[0063] 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.

[0064] <Overall Configuration> Fig. 1 is a diagram illustrating an example of the overall configuration of an inkjet recording system S. Fig. 2 is a diagram illustrating an example of the schematic configuration of an inkjet recording apparatus I, and Figs. 3, 4A, and 4B are diagrams illustrating an example of the schematic configuration of a print head 1 in the inkjet recording apparatus I. Finally, Fig. 5 is a diagram illustrating an example of the paths of ink and solvent in the inkjet recording apparatus I.

[0065] The inkjet recording system S illustrated in FIG. 1 is installed on a conveying line L in a factory or the like, for example, and is configured to print on each print target W flowing along the conveying line L in order. The application of the present disclosure is not limited to the inkjet recording system S. It can also be applied to printing systems that use methods other than automatic methods. The conveying line L can be configured, for example, with a belt conveyor. The term "print target" may also be referred to as "print object" in the following description.

[0066] Specifically, the inkjet recording system S includes an inkjet recording apparatus I that performs printing by causing particulate ink (ink particles) to land on a print target W, and an operation terminal 800 and external device 900 that are connected to the inkjet recording apparatus I. Note that the operation terminal 800 and the external device 900 are not essential.

[0067] The inkjet recording device I shown in Figures 1 to 3 comprises a print head 1 that ejects ink droplets from nozzles 12 and causes the ink droplets to land on a print substrate 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 control signals to the print head 1. This adjusts the landing positions of the ink droplets on the print substrate W, thereby achieving the desired printing. The print head 1 is fixed in a predetermined position by a support member 2 or the like.

[0068] The inkjet recording apparatus I is a continuous ink jet printer (CIJ). 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 a continuous system, quick-drying ink can be used without causing clogging due to ink.

[0069] The inkjet recording apparatus I according to this embodiment is also capable of adjusting the ink concentration (viscosity) by mixing the ink with a solvent. The inkjet recording apparatus I can also clean various parts of the print head 1, such as the nozzles 12, by sending a solvent to the print head 1. The solvent used for cleaning can be recovered as needed and reused to adjust the ink concentration (viscosity).

[0070] 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.

[0071] On the other hand, the operation terminal 800 has, for example, a central processing unit (CPU) and a storage device, and is connected to the controller 100. This operation terminal 800 determines print settings and functions as a terminal for presenting information related to printing to the user.

[0072] The print settings set by the operation terminal 800 are output to the controller 100 and stored in its memory unit 102. In addition to or instead of the memory unit 102 of the controller 100, the operation terminal 800 may store the print settings.

[0073] The print settings according to this embodiment may include conditions and parameters related to head cleaning, which will be described later, in addition to the content of the character string to be printed.

[0074] 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 a control unit is used.

[0075] 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.

[0076] Specifically, the workpiece detection sensor 901 detects the presence or absence of a print object 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.

[0077] The transport speed sensor 902 is composed of, for example, a rotary encoder, and is capable of detecting the transport speed of the print substrate W. The transport 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 transport speed sensor 902.

[0078] 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.

[0079] In addition to the above-mentioned devices and equipment, devices for operation and control, computers for performing various other processes, storage devices, peripheral devices, etc. can also be connected to the inkjet recording apparatus I. In such cases, the connection method may be either wired or wireless.

[0080] <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.

[0081] Specifically, the controller 100 according to this embodiment includes, as components related to electrical control, a memory unit 102 that stores the print settings described above, 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.

[0082] The controller 100 also includes components related to the supply of ink and the like, such as an ink supply unit 104, a solvent supply unit 105, and an ink tank 106. These components are directly or indirectly fluidly connected to the print head 1. In at least this embodiment, the controller 100 houses the ink supply unit 104, the solvent supply unit 105, and the control unit 101 inside.

[0083] The ink supply unit 104 has an ink reservoir 42 that detachably receives an ink cartridge 41 that contains ink. The ink supply unit 104 supplies ink to the print head 1.

[0084] On the other hand, the solvent supply unit 105 has a solvent reservoir 52 that detachably receives a solvent cartridge 51 that contains a solvent. The solvent supply unit 105 supplies ink to the print head 1.

[0085] The ink tank 106 stores, as printing ink, the ink from the ink cartridge 41 received in the ink reservoir 42 and the solvent from the solvent cartridge 51 received in the solvent reservoir 52. The term "printing ink" used here refers to a mixture of solvent and ink (for example, ink whose concentration has been adjusted by the solvent).

[0086] The print head 1 then prints using printing ink from the ink tank 106. The print head 1 also cleans the nozzles 12 and other components within the print head 1 with solvent supplied from a solvent supply unit 105 that bypasses the ink tank 106.

[0087] Additionally, the controller 100 according to this embodiment has an air generating unit 108 as an element related to the cleaning process of the print head 1. The air generating unit 108 is housed inside the controller 100. Details of the air generating unit 108 will be described later. Furthermore, the cleaning process of the print head 1 referred to here refers to a process of using a solvent to clean the inside of the print head 1, and in particular the parts housed inside the print head 1. Hereinafter, this cleaning process will also be referred to as "head cleaning".

[0088] Head cleaning is assisted by an assist module 70 of the inkjet recording system S. The assist module 70 according to this embodiment is made up of an air generating unit 108 of the controller 100 and an assist unit 18 of the print head 1. Details of the air generating unit 108 and the assist unit 18 will be described later.

[0089] 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.

[0090] Furthermore, regarding the ink supply unit 104 and the ink tank 106 as independent components is merely a classification for the sake of convenience. From the viewpoint of being related to the supply of ink, the ink tank 106 may be considered as one element of the ink supply unit 104.

[0091] (Memory unit 102) The memory unit 102 is configured to store print settings set via the operation display unit 103 or the operation terminal 800 described below, and to output the stored print settings to the control unit 101 based on a control signal from outside.

[0092] Specifically, the storage unit 102 is configured using a volatile memory, a non-volatile memory, a solid state drive (SSD), a hard disk drive (HDD), etc., and can temporarily or continuously store information indicating print settings. Note that, if the operation terminal 800 is incorporated into the controller 100, the operation terminal 800 may also serve as the storage unit 102.

[0093] (Controller 101 ) The controller 101 is a processing unit that controls the supply of ink from the ink supply unit 104 to the print head 1 , and also controls the supply of solvent from the solvent supply unit 105 to the print head 1 .

[0094] In detail, the control unit 101 controls at least the ink supply unit 104 and solvent supply unit 105 in the controller 100, and the nozzles 12, charging electrodes 13, and deflection electrodes 15 in the print head 1, based on the print settings stored in the memory unit 102. The control unit 101 controls each unit, so that printing on the print target W is performed at a predetermined timing.

[0095] More 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 print settings read from the storage unit 102. The control unit 101 controls printing on the print target W by outputting the generated control signal to the controller 100 and each part of the inkjet recording apparatus I.

[0096] For example, when printing on the print target W, the control unit 101 reads the print content for the print target W stored in the storage unit 102 and generates a control signal based on the print content. Then, the control unit 101 outputs the control signal to the charging electrode 13, thereby setting the flight direction of the ink droplets so as to achieve a landing position corresponding to the print content.

[0097] -Other functional elements in the control unit 101- In addition, the control unit 101 according to this embodiment includes a cleaning control unit 101a, as an example of a functional element that executes processes related to head cleaning, shown in Fig. 2. Details of the cleaning control unit 101a will be described later.

[0098] 1, the operation display unit 103 includes a display unit 103a that displays information to the user and an operation unit 103b that accepts operations by the user. The operation display unit 103 can be provided, for example, on a housing that constitutes the controller 100, but it may also be configured separately from the housing and set in a location different from the housing. Furthermore, if an operation terminal 800 is incorporated into the controller 100, the operation terminal 800 may also serve as the operation display unit 103.

[0099] The display unit 103a displays various information related to the inkjet recording apparatus I. The display unit 103a is configured with, for example, a liquid crystal display panel or an organic EL display panel, and changes the display mode upon receiving a control signal from the control unit 101. The display unit 103a can display a user interface for operating each unit of the inkjet recording system S, a user interface for determining print settings, and a user interface related to head cleaning.

[0100] The operation unit 103b is configured by, for example, a touch panel, buttons, switches, etc. When a user operates the operation unit 103b, information corresponding to the operation input (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, perform various settings, input information, etc.

[0101] This operation display unit 103 can also set print settings, similar to the above-mentioned operation terminal 800. The print settings set by the operation display unit 103 are output to the controller 100 and stored in its storage unit 102. In the following description, it is assumed that the user operates the operation display unit 103, but the operation terminal 800 can also be used instead of the operation display unit 103.

[0102] (Ink supply unit 104) The ink supply unit 104 supplies ink from the ink cartridge 41 as printing ink to the nozzles 12 of the print head 1. At this time, the ink from the ink supply unit 104 is supplied to the print head 1 via an ink tank 106.

[0103] Specifically, the ink supply unit 104 according to this embodiment has, as its main components, the ink cartridge 41 and ink reservoir 42 described above, a hollow ink needle 43 as a hollow needle, and an ink supply tube 44. The ink hollow needle 43 fluidly connects the ink cartridge 41 and the ink supply tube 44. The ink supply tube 44 fluidly connects the ink cartridge 41 and the print head 1 via the ink hollow needle 43. An ink tank 106 is disposed midway along the ink supply tube 44, which runs from the ink hollow needle 43 to the print head 1.

[0104] Of these, the ink cartridge 41 contains ink. The ink reservoir 42 detachably receives the ink cartridge 41. By replacing the ink cartridge 41 with the ink reservoir 42, the ink tank 106 can be replenished with ink. In other words, the inkjet recording apparatus I according to this embodiment is configured as a so-called "cartridge-type" inkjet printer.

[0105] As shown only in FIG. 5, the ink reservoir 42 is provided with a first attachment sensor SW1 that detects whether the ink cartridge 41 or the solvent cartridge 51 is attached to the ink reservoir 42.

[0106] The ink hollow needle 43 accesses the ink in the ink cartridge 41 when the ink reservoir 42 receives the ink cartridge 41 (when the ink cartridge 41 is attached to the ink reservoir 42).

[0107] The ink supply pipe 44 constitutes a path for supplying printing ink to the print head 1. The path formed by the ink supply pipe 44 allows ink to circulate between the print head 1 and the controller 100.

[0108] As will be described later, the ink supply pipe 44 is provided with a plurality of on-off valves, including the first valve V1, and a plurality of pumps, including the first pump P1. Each of these on-off valves is configured as an electromagnetic valve. Each on-off valve receives a control signal from the control unit 101 to open or close, thereby controlling the flow of ink. Meanwhile, each pump receives a control signal from the control unit 101 to pump ink, thereby controlling the flow of ink in the same manner as the on-off valves. Note that at least some of the on-off valves (e.g., the first valve V1, the eighth valve V8, the eleventh valve V11, and the eighteenth valve V18 in FIG. 5 ) may be manual cocks instead of electromagnetic valves.

[0109] (Solvent supply unit 105) The solvent supply unit 105 supplies the solvent from the solvent cartridge 51 to the ink tank 106 in the same way as the ink, or supplies the solvent alone to the nozzles 12. The former solvent adjusts the concentration of the ink, and together with the ink, it forms printing ink and is supplied to the print head 1.

[0110] When forming printing ink together with ink (i.e., when printing is performed on the print head 1), the solvent from the solvent supply unit 105 is led to the nozzle 12 via the ink tank 106. On the other hand, when the solvent is supplied alone (for example, when performing head cleaning, which will be described later), the solvent from the solvent supply unit 105 is led to the nozzle 12 without passing through the ink tank 106.

[0111] Specifically, the solvent supply unit 105 according to this embodiment has, as its main components, the above-mentioned solvent cartridge 51, solvent reservoir 52, hollow solvent needle 53, and solvent supply pipe 54. The hollow solvent needle 53 fluidly connects the solvent cartridge 51 and the solvent supply pipe 54. The solvent supply pipe 54 fluidly connects, via the hollow solvent needle 53, the solvent cartridge 51 and the print head 1, and the solvent cartridge 51 and the ink tank 106.

[0112] Of these, the solvent cartridge 51 contains a solvent. The solvent reservoir 52 detachably receives the solvent cartridge 51. By replacing the solvent cartridge 51 with the solvent reservoir 52, it is possible to replenish the solvent for concentration adjustment and the solvent for cleaning. In other words, the inkjet recording apparatus I according to this embodiment is configured as a "cartridge-type" inkjet printer for solvent as well.

[0113] As shown only in FIG. 5, the solvent reservoir 52 is provided with a second installation sensor SW2 that detects whether the solvent cartridge 51 or the ink cartridge 41 is installed in the solvent reservoir 52.

[0114] The hollow solvent needle 53 accesses the solvent in the solvent cartridge 51 when the solvent reservoir 52 receives the solvent cartridge 51 (when the solvent cartridge 51 is attached to the solvent reservoir 52).

[0115] The solvent supply pipe 54 constitutes a path for supplying solvent to the ink tank 106, and for supplying solvent to the print head 1 without the ink tank 106. These paths make it possible to produce printing ink from ink and solvent, and to clean the print head 1 with solvent.

[0116] The classification of the ink supply pipe 44 and the solvent supply pipe 54 is merely a convenient classification made for the sake of simplicity of explanation. The ink supply pipe 44 and the solvent supply pipe 54 are essentially inseparable because they are connected to each other or one serves the other.

[0117] As will be described later, the solvent supply pipe 54 is provided with a plurality of on-off valves, including the twelfth valve V12, and a plurality of pumps, including the second pump P2. Each of these on-off valves is configured as a solenoid valve. Each on-off valve receives a control signal from the control unit 101 to open or close, thereby controlling the flow of the solvent. Meanwhile, each pump receives a control signal from the control unit 101 to pump the solvent, thereby controlling the flow of the solvent in the same manner as the solenoid valves. As mentioned above, manual cocks may be used instead of the solenoid valves.

[0118] (Ink Tank 106) The ink tank 106 is configured to store the ink from the ink cartridge 41 and the solvent from the solvent cartridge 51. More specifically, the ink tank 106 is configured as a container that stores ink whose concentration (viscosity) has been adjusted with a solvent, i.e., a mixture of ink and solvent.

[0119] The printing ink supplied from the ink tank 106 to the nozzles 12 lands on the surface of the print target W during printing, and is collected by the gutter 16 and returned to the ink tank 106 during non-printing. This allows the printing ink to be circulated.

[0120] In addition, the solvent supplied to the nozzle 12 for cleaning can also be collected by the gutter 16 and then sent to the ink tank 106 via, for example, a conditioning tank (not shown) dedicated to the solvent, where it can be reused to adjust the ink concentration.

[0121] The ink tank 106 is also provided with a storage sensor 106a for detecting the liquid level (so-called liquid surface level) within the tank. The storage sensor 106a is electrically connected to the control unit 101, and inputs its detection signal to the controller 100. The storage sensor 106a may be configured as an electrode-type level sensor, a float-type level sensor, or a capacitance-type level sensor.

[0122] (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 .

[0123] (Other Components) The controller 100 is provided with a connection cable 107, which is a bundle of covered power wiring for sending and receiving control signals, tubes for sending and receiving ink (specifically, the tubes that make up the ink supply pipe 44), and tubes for sending and receiving solvent (specifically, the tubes that make up the solvent supply pipe 54). 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.

[0124] <Print Head 1> The print head 1 ejects ink (printing ink) whose concentration has been adjusted based on a control signal, ink, and solvent supplied from the controller 100, in the form of particulate ink (hereinafter also referred to as "ink particles"). The print head 1 deflects the flight direction of the ejected ink particles and causes the deflected ink particles to land on the surface of the print target W, thereby executing printing on the print target W. The details of the printing at this time follow the print settings described above. The print head 1 can print sequentially on each of the print target W in accordance with the print settings.

[0125] Specifically, as shown in Figure 3, the print head 1 according to this embodiment includes a pressurizer 11, a nozzle 12, a charging electrode 13, a deflection electrode 15, a gutter 16, a cleaning nozzle 17, a shutter 21, a suction device 22, a filter 23, and a posture sensor 24. The pressurizer 11 applies pressure to the printing ink to turn it into particulate ink. The nozzle 12 ejects the particulate ink. The charging electrode 13 charges the particulate ink ejected from the nozzle 12. The deflection electrode 15 deflects the flying deflection of the printing ink charged by the charging electrode 13. The gutter 16 collects the printing ink that has been undeflected by the deflection electrode 15, or the solvent ejected from the nozzle 12. The shutter 21, suction device 22, filter 23, and posture sensor 24 are not essential.

[0126] In addition, as elements related to the acquisition of various parameter values, the print head 1 is equipped with a charge detection sensor 14 that monitors the charged state of the printing ink, and a gutter sensor 16b that detects whether ink has entered the gutter 16.

[0127] The print head 1 houses a pressure device 11, a nozzle 12, a charging electrode 13, a charge detection sensor 14, a deflection electrode 15, a gutter 16, and a cleaning nozzle 17, and ejects printing ink deflected by the deflection electrode 15 to the outside. The inkjet recording apparatus I according to this embodiment performs printing by causing the ink deflected by the deflection electrode 15 to land on a printing target.

[0128] More specifically, the print head 1 includes a housing 10 that houses a pressurizer 11, a nozzle 12, a charging electrode 13, a charge detection sensor 14, a deflection electrode 15, a gutter 16, a gutter sensor 16b, and a cleaning nozzle 17, 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.

[0129] 3, the housing 10 extends in the vertical direction on the paper. In the following description, the longitudinal direction of the housing 10 will be simply referred to as the "vertical direction," while the two directions perpendicular to this vertical direction will be referred to as the "front-rear direction" and the "left-right direction," respectively. In other figures, the corresponding directions will also be referred to as the "vertical direction," "front-rear direction," and "left-right direction," respectively.

[0130] Here, "top" refers to the top side of the page in Fig. 3, and "bottom" refers to the bottom side of the page. Similarly, "front" refers to the front side of the page in Fig. 3 (specifically, the front left side), "back" refers to the back side of the page (specifically, the back right side), "left" refers to the left side of the page (specifically, the upper left side), and "right" refers to the right side of the page (specifically, the lower right side). In other figures, the corresponding terms are referred to as "top," "bottom," "front," "back," "left," and "right," respectively.

[0131] The print head 1 does not necessarily have its up-down direction aligned with the vertical direction (the direction of gravity). The print head 1 can also be oriented with its up-down direction aligned with the horizontal direction.

[0132] The print head 1 also has ink ejection ports 10a for ejecting ink deflected by the deflection electrodes 15 to the outside. As shown in Figure 3, these ink ejection ports 10a open to the bottom surface of a housing 10 that forms the outer shape of the print head 1. Hereinafter, the ink ejection ports 10a will also be simply referred to as ejection ports 10a. Ink droplets are ejected from these ejection ports 10a downward into the housing 10.

[0133] 1, during printing, the print head 1 is supported, for example, by a support member 2. When supported by the support member 2, the print head 1 is positioned so that its ejection ports 10a face from above the printing surface of the print substrate W. This location is an example of where the print head 1 may be installed when printing using the inkjet recording apparatus I.

[0134] Below, we will explain each part of the print head 1 in order. In the following description, the "up-down direction" refers to the direction along the vertical. For example, the top of the paper in Figure 3 corresponds to the "upward direction," and the bottom of the ground in the same figure corresponds to the "downward direction."

[0135] 3, the pressurizer 11 is disposed near the upper end of the flight space S1 of the housing 10. This pressurizer 11 is configured to receive printing ink from the ink tank 106 via a connection cable 107.

[0136] The pressurizer 11 pressurizes the ink liquid supplied from the ink tank 106. The ink pressurized by the pressurizer 11 is supplied to the nozzles 12. Although not shown in the drawings, the pressurizer 11 according to this embodiment is grounded.

[0137] (Nozzle 12) The nozzle 12 is connected to the lower end of the pressurizer 11 and is positioned with its open end (printing ink) facing downward. The nozzle 12 has a piezoelectric element (e.g., a piezo element) that applies up and down vibrations to the ink, and applies up and down vibrations to the ink pressurized by the pressurizer 11 before ejecting it from the ejection port (open end). This vibration causes the ink liquid ejected from the nozzle 12 to become particles a predetermined time after the ejection timing.

[0138] Here, printing ink ejected from the nozzle 12 without being subjected to vibration (excited) flows as an axial, so-called "ink axis." On the other hand, printing ink ejected from the nozzle 12 after being subjected to vibration (excited) is axially shaped immediately after being ejected from the nozzle 12, but becomes particulate as it moves away from the nozzle 12. The particulate printing ink falls as so-called "ink droplets." The printing ink passes through the charged electrode 13, regardless of whether it is an ink axis or ink droplets. Note that by ejecting a solvent alone from the nozzle 12, the solvent can be made to flow axially. Hereinafter, such an axial solvent will also be referred to as a "solvent axis." The central axis of the ink axis and the solvent axis is as shown by the two-dot chain line Ax in FIG. 4A.

[0139] In addition, if the nozzle 12 is equipped with a piezoelectric element, the ink atomization can be controlled by the voltage (piezoelectric voltage) applied to the piezoelectric element. In this embodiment, the controller 100 is configured to apply a controllable piezoelectric voltage to the piezoelectric element of the nozzle 12.

[0140] The solvent supplied to clean the inside of the print head 1 passes through the pressurizer 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.

[0141] 5 is connected to the nozzle 12 as a return path for releasing pressure inside the print head 1 when, for example, the inkjet recording apparatus I is shut down. Solvent can also be sucked from the nozzle 12 through this suction path 47.

[0142] (Charged electrode 13) As illustrated in Fig. 3, the charged electrode 13 is made up of a pair of electrically conductive metal plates, and is arranged below the nozzle 12. Here, the pair of metal plates that make up the charged electrode 13 are fixed to the housing 10 in an orientation in which their respective longitudinal directions are aligned in the up-down direction and in which they face 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 printing ink ejected from the nozzle 12 passes between the pair of metal plates. Note that the number of metal plates that make up the charged electrode 13 does not need to be a pair.

[0143] A potential (positive potential) is applied to the charging electrode 13 at least when a printing operation is performed. This generates a potential difference between the pressure generator 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 printing ink ejected from the nozzle 12 breaks down into particles.

[0144] More specifically, 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.

[0145] 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.

[0146] 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 (the metal plate on the right side of the drawing in the example) that constitutes the charging electrode 13 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.

[0147] 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 it (particularly the amount of charge on each ink particle). 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.

[0148] 3, the deflection electrode 15 is composed of a pair of electrically 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.

[0149] A voltage (hereinafter also referred to as "deflection voltage") that can be controlled by the controller 100 is applied to the deflection electrode 15. As a result, a potential difference corresponding to the deflection voltage is generated between the pair of metal plates that make up the deflection electrode 15. This potential difference can deflect the flight direction of ink particles according to the charge amount of 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.

[0150] That is, the flight direction of the ink particles can be controlled via the deflection 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 ink particles). Of these, the ink particles deflected by the deflection electrode 15 are involved in printing on the print target W. The ink particles deflected by the deflection electrode 15 are ejected from the ejection port 10a provided on the bottom surface of the housing 10 and land on the print target W.

[0151] On the other hand, ink particles that are not deflected by the deflection electrode 15 do not participate in printing on the print substrate W. These ink particles, or axial printing 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.

[0152] -Details of Deflection Electrode 15- Specifically, the deflection electrode 15 according to this embodiment is composed of first and second electrode plates 151 and 152 facing each other. The first electrode plate 151 is grounded. The first electrode plate 151 can also be called a ground electrode. A high voltage is applied to the second electrode plate 152.

[0153] The first electrode plate 151 faces the second electrode plate 152 with a gap therebetween. The first electrode plate 151 has a first opposing surface 151 a. The first opposing surface 151 a extends in the up-down direction and faces the second electrode plate 152.

[0154] On the other hand, the second electrode plate 152 has a second opposing surface 152a, an inclined surface 152b, and a curved surface 152c. The second opposing surface 152a and the inclined surface 152b are continuous in the vertical direction from the nozzle 12 side toward the ejection port 10a side. The inclined surface 152b and the curved surface 152c are continuous in the vertical direction from the nozzle 12 side toward the ejection port 10a side.

[0155] The second opposing surface 152a extends straight in the vertical direction and parallel to the first opposing surface 151a.

[0156] The inclined surface 152b extends from the tip of the second opposing surface 152a on the ejection port 10a side. The inclined surface 152b extends in the vertical direction and is inclined in the direction away from the central axis Ax connecting the nozzle 12 and the gutter 16 (see FIG. 4A).

[0157] The bent surface 152c extends from the tip of the inclined surface 152b on the ejection port 10a side. The bent surface 152c bends more steeply than the inclined surface 152b in a direction away from the ink axis or the solvent axis, that is, in a direction away from the central axis Ax that connects the nozzle 12 and the gutter 16 along the vertical direction (see FIG. 4A).

[0158] More specifically, the extension line El extending from the tip of the bent surface 152c (particularly the tip on the outlet 10a side) does not intersect with the outlet 10a, but extends so as to intersect with the side wall portion 10s of the housing 10 around the outlet 10a, as shown in FIG. 4A.

[0159] 3, the gutter 16 is configured as a curved pipe with its opening 16a facing upward, and is disposed below the deflection electrode 15. The gutter 16 according to this embodiment can collect printing ink that is not involved in printing on the print target W and the solvent that has passed through the nozzle 12 (specifically, the solvent ejected from the nozzle 12).

[0160] More specifically, in this embodiment, the opening 16a 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 opening 16a of the gutter 16. By arranging them in this manner, it becomes possible for the fluid that flows or is ejected vertically from the open end of the nozzle 12 to be received by the opening 16a of the gutter 16.

[0161] The gutter 16 is provided with a charge-type or thermistor-type gutter sensor 16b (see FIG. 3). The gutter sensor 16b detects whether printing ink is in the gutter 16, and determines that ink axis adjustment is complete if printing ink is in the gutter 16, and determines that ink axis adjustment is not complete if printing ink is not in the gutter 16. The gutter sensor 16b is connected to the control unit 101 of the controller 100, and is configured to output a signal to the control unit 101.

[0162] The printing ink or solvent collected by the gutter 16 is returned to the controller 100 via the ink supply pipe 44, the solvent supply pipe 54, etc., and is stored in the ink tank 106.

[0163] The printing ink or solvent collected by the gutter 16 is returned to the controller 100 via the ink supply pipe 44, the solvent supply pipe 54, etc., and is stored in the ink tank 106.

[0164] (Cleaning nozzle 17) As shown in Figure 3, the cleaning nozzle 17 is provided inside the print head 1. The cleaning nozzle 19 functions as a so-called solvent spraying unit. The cleaning nozzle 19 is a nozzle for spraying a solvent onto the nozzles 12, charging electrodes 13, deflection electrodes 15, etc. of the print head 1 to clean them, and is capable of spraying solvent as a cleaning liquid. The solvent sprayed from the cleaning nozzle 17 is supplied from a solvent supply unit 105, for example, a solvent cartridge 51.

[0165] In this embodiment, as illustrated by the reference symbol L1 in Fig. 4B , the solvent sprayed from the cleaning nozzle 17 is sprayed at least onto the nozzle 12. This makes it possible to clean the nozzle 12. By cleaning the nozzle 12, the solvent can be smoothly ejected from the nozzle 12 during head cleaning.

[0166] (Shutter 21) The shutter 21 opens and closes the ejection port 10a. The shutter 21 is electrically connected to the control unit 101 and opens and closes in response to a control signal from the control unit 101. Closing the ejection port 10a with the shutter 21 can prevent solvent from leaking from the ejection port 10a, for example, during head cleaning. Note that instead of closing the ejection port 10a with the shutter 21, the ejection port 10a may be closed with a cap or the like.

[0167] (Aspirator 22) The aspirator 22 sucks air from the internal space of the print head 1, particularly from the inside of the flight space, and exhausts it to the external space of the print head 1. The aspirator 22 is electrically connected to the control unit 101 and operates in response to a control signal from the control unit 101. When the aspirator 22 operates, it can suck in and exhaust air from the internal space of the print head 1. The aspirator 22 is an example of the "suction unit" and "drying unit" in this embodiment. Note that continuous inkjet recording devices (CIJ) are installed in various factories, for example, and therefore compliance with various laws and regulations, such as ensuring safety, is important. The provision of the aspirator 22 also has the advantage of making it easier to comply with laws and regulations by making it less likely for misted solvent to leak from the ink ejection ports.

[0168] (Filter 23) The filter 23 filters the air sucked in by the suction device 22. By filtering the air with the filter 23, it is possible to remove solvents contained in the air (especially evaporated solvents) and odors from inside the print head 1.

[0169] (Attitude sensor 24) The attitude sensor 24 detects the attitude of the print head 1. The attitude sensor 24 is, for example, an acceleration sensor or a gravity sensor. As shown in Figure 3, the attitude sensor 24 is attached to the print head 1. The attitude sensor 24 is electrically connected to the control unit 101, and inputs a detection signal to the control unit 101.

[0170] (Assist Unit 18) As shown in Figure 3, the print head 1 further includes an assist unit 18. The assist unit 18 assists in cleaning the components housed inside the print head 1 using solvent supplied from the solvent supply unit 105. The "cleaning" referred to here is nothing other than the "head cleaning" described above. The components cleaned by head cleaning include at least one of the gutter 16, nozzle 12, and deflection electrode 15. The assist unit 18, together with the air generation unit 108 described above, constitutes the assist module 70 in this embodiment.

[0171] Furthermore, the term "assist" in this disclosure includes at least "air assist" using air and "mechanical assist" using a mechanical element. The assist unit 18 according to this embodiment performs the former "air assist." When performing air assist, the assist unit 18 blows air from the air injection unit 181 onto the solvent supplied inside the print head 1.

[0172] The configuration relating to "air assist" is exemplified in this embodiment and in the first modified example described later. The configuration relating to "mechanical assist" is exemplified in the second and third modified examples described later.

[0173] In either configuration, the configuration and structure of the assist unit 18 are closely related to the supply of solvent from the solvent supply unit 105 to the print head 1. Therefore, before describing the assist unit 18 and, in turn, the assist module 70 in detail, the configuration related to the ink and solvent distribution paths in the inkjet recording apparatus I, specifically, the configuration related to the ink supply pipe 44 and the solvent supply pipe 54, will be described with reference to FIG.

[0174] <Ink and Solvent Distribution Paths> As described above, the ink supply pipe 44 supplies ink from the ink cartridge 41 to the ink tank 106, and also supplies printing ink from the ink tank 106 to the print head 1. Meanwhile, the solvent supply pipe 54 supplies solvent from the solvent cartridge 51 to both the print head 1 and the ink tank 106.

[0175] -First Route R1- The ink supply pipe 44 constitutes a route (first route R1) for sending ink (ink before concentration adjustment) from the ink cartridge 41 to the ink tank 106, for example.

[0176] 5, the first path R1 according to the present embodiment is configured by a first ink tube 44a, a second ink tube 44b, and a third ink tube 44c, which serve as ink flow tubes. In the present embodiment, the first ink tube 44a, the second ink tube 44b, and the third ink tube 44c are all disposed inside the controller 100.

[0177] The first ink tube 44a has one end connected to the ink hollow needle 43 and the other end branching into a second ink tube 44b and a third ink tube 44c (see branching portion B1 in FIG. 5 ). The first ink tube 44a, which serves as an ink distribution tube, connects the ink hollow needle 43 and the ink tank 106 via the second ink tube 44b and the third ink tube 44c, allowing ink to flow from the ink hollow needle 43 to the ink tank 106. In this embodiment, ink is introduced into the ink tank 106 via the third ink tube 44c, but it may also be introduced via the second ink tube 44b, for example. In this case, the ink is introduced into the ink tank 106 without passing through the viscometer 46.

[0178] The classification of the ink tubes as the first ink tube 44a, the second ink tube 44b, and the third ink tube 44c is merely for convenience. For example, the first ink tube 44a and the second ink tube 44b may be considered as a single ink distribution tube. In that case, the ink distribution tube formed by the first ink tube 44a and the second ink tube 44b would directly connect the ink hollow needle 43 and the ink tank 106.

[0179] A first pump P1 is disposed midway along the first ink tube 44a. This first pump P1 is a suction pump that draws ink from the ink hollow needle 43 to the first ink tube 44a, causing the ink to flow.

[0180] A junction 45 is disposed in the first ink tube 44a between the ink hollow needle 43 and the first pump P1. This junction 45 is configured to merge the solvent or ink in the first ink tube 44a. In particular, the junction 45 illustrated in FIG. 5 is connected to the third solvent tube 54c of the solvent supply tube 54 and is configured to merge the solvent of the ink and solvent with the ink flowing in the first ink tube 44a. The ink that merges in the first ink tube 44a may be printing ink.

[0181] An eighth valve V8 is disposed in the first ink pipe 44a between the junction 45 and the first pump P1. The eighth valve V8 is an on-off valve that opens and closes the flow path of the first ink pipe 44a.

[0182] The second ink tube 44b connects the other end (branch portion B1) of the first ink tube 44a to the ink tank 106. A first valve V1 is disposed midway along the second ink tube 44b. This first valve V1 is an on-off valve that opens and closes the flow path of the second ink tube 44b.

[0183] The third ink tube 44c connects the other end (branch portion B1) of the first ink tube 44a to the ink tank 106. An eleventh valve V11 is disposed midway along the third ink tube 44c. This eleventh valve V11 is an on-off valve that opens and closes the flow path of the third ink tube 44c.

[0184] Furthermore, a viscometer 46 is disposed in the third ink tube 44c between the eleventh valve V11 and the ink tank 106. This viscometer 46 detects the flow rate of the ink or printing ink flowing through the third ink tube 44c and measures the viscosity based on that flow rate. The viscometer 46 inputs a detection signal corresponding to the measurement result to the control unit 101. Note that, although the present embodiment uses a viscometer 46 that operates on the principle of detecting the ink flow rate, the present invention is not limited to this. For example, a viscometer 46 that repeatedly fills and discharges ink and measures the viscosity based on the time it takes for the ink to be discharged may also be used.

[0185] Ink from the ink cartridge 41 is supplied to the ink tank 106 by passing through the ink hollow needle 43, the ink reservoir 42, the first ink tube 44a, the second ink tube 44b and the third ink tube 44c in that order based on the operating status of the first pump P1 and the open / close status of the first valve V1, the fifth valve V5 and the eighth valve V8.

[0186] - Second Route R2 - Meanwhile, the solvent supply pipe 54, together with some elements of the ink supply pipe 44, constitutes a route (second route R2) for sending the solvent from the solvent cartridge 51 to the ink tank 106.

[0187] 5, the second path R2 according to this embodiment is made up of the first solvent pipe 54a of the solvent supply pipe 54, a portion of the first ink pipe 44a (the portion from the connection point B2 to the branch point B1 in FIG. 5), and the entire second ink pipe 44b and the entire third ink pipe 44c. In this embodiment, the first solvent pipe 54a is disposed inside the controller 100.

[0188] As mentioned above, the names ink supply pipe 44 and solvent supply pipe 54 are given for convenience only, focusing on one side of each flow pipe. The first ink pipe 44a, the second ink pipe 44b, and the third ink pipe 44c may serve both ink and solvent. Each flow pipe may contribute to the formation of one or more paths.

[0189] The first solvent pipe 54a has one end connected to the ink hollow needle 43 and the other end (connection portion B2) connected to the first ink pipe 44a. A thirteenth valve V13 is disposed midway along the first solvent pipe 54a in the solvent supply pipe 54. The thirteenth valve V13 is an on-off valve that opens and closes the flow path of the first solvent pipe 54a.

[0190] The solvent from the solvent cartridge 51 passes through the hollow solvent needle 53, the solvent reservoir 52, and the first solvent pipe 54a in this order, depending on the operating status of the first pump P1 and the open / close status of the thirteenth valve V13, and is then supplied to a midpoint of the first ink pipe 44a (see connection B2 in FIG. 5). The solvent supplied to this point passes through the first ink pipe 44a, the second ink pipe 44b, and the third ink pipe 44c in this order, depending on the open / close status of the first valve V1 and the eleventh valve V11, and is then supplied to the ink tank 106.

[0191] The ink supplied through the first route R1 has its concentration adjusted by the solvent supplied through the second route R2, and thus the ink for printing is stored in the ink tank 106.

[0192] —Third Route R3— Returning to the explanation of the ink supply pipe 44, this ink supply pipe 44 also constitutes a route (third route R3) for circulating and stirring the contents (printing ink) of the ink tank 106 within the controller 100.

[0193] 5, the third path R3 according to this embodiment is made up of the fourth ink tube 44d and the fifth ink tube 44e of the ink supply tube 44, a portion of the first ink tube 44a (the portion from the connection portion B2 to the branch portion B1 in FIG. 5), and the entire second ink tube 44b and the entire third ink tube 44c. In this embodiment, the fourth ink tube 44d and the fifth ink tube 44e are both disposed inside the controller 100.

[0194] The fourth ink tube 44d has one end connected to the ink tank 106 and the other end (connection portion B2) connected to the first ink tube 44a. A ninth valve V9 is disposed midway along the fourth ink tube 44d. This ninth valve V9 is an on-off valve that opens and closes the flow path of the fourth ink tube 44d.

[0195] The fifth ink tube 44e has one end connected to the ink tank 106 and the other end (connection part B2) connected to the first ink tube 44a. A fifth valve V5 is disposed midway along the fifth ink tube 44e. This fifth valve V5 is an on-off valve that opens and closes the flow path of the fifth ink tube 44e.

[0196] In addition, the connection position between the fourth ink tube 44d and the ink tank 106 (the position where printing ink is sucked by the fourth ink tube 44d) is positioned higher in the height direction of the ink tank 106 than the connection position between the fifth ink tube 44e and the ink tank 106 (the position where printing ink is sucked by the fifth ink tube 44e).

[0197] The printing ink in the ink tank 106 is sucked out by the fourth ink tube 44d or the fifth ink tube 44e based on the operating status of the first pump P1 and the open / close status of the first valve V1, the fifth valve V5, the ninth valve V9, and the eleventh valve V11, and then passes through a part of the first ink tube 44a (the portion from the connection part B2 to the branch part B1 in FIG. 5), the second ink tube 44b, and the third ink tube 44c in that order before being sent back to the ink tank 106. In this way, the printing ink circulates within the controller 100.

[0198] Furthermore, by configuring the controller 100 so that the printing ink is not simply circulated within the controller 100 but is instead drawn out from two locations at different heights, the printing ink can be stirred within the ink tank 106. This makes it possible to make the concentration of the printing ink uniform (maintaining the pigment dispersion state). This configuration is particularly effective when pigment ink is used.

[0199] -Fourth Route R4- The ink supply pipe 44 further constitutes a route (fourth route R4) for sending printing ink from the ink tank 106 to the nozzles 12 and returning printing ink from the gutter 16 to the ink tank 106.

[0200] 5, the fourth path R4 according to this embodiment is made up of the sixth ink tube 44f and the seventh ink tube 44g of the ink supply tube 44. Both the sixth ink tube 44f and the seventh ink tube 44g connect the controller 100 and the print head 1.

[0201] The sixth ink tube 44f has one end connected to the ink tank 106 and the other end connected to the nozzle 12. A third pump P3 is disposed midway along the sixth ink tube 44f. The third pump P3 is a suction pump that draws ink from the ink tank 106 to create a flow toward the sixth ink tube 44f.

[0202] A fourteenth valve V14 is disposed in the sixth ink pipe 44f between the third pump P3 and the nozzle 12. The fourteenth valve V14 is an on-off valve that opens and closes the flow path of the sixth ink pipe 44f.

[0203] The seventh ink tube 44g has one end connected to the gutter 16 and the other end connected to the ink tank 106. A fourth pump P4 is disposed midway along the seventh ink tube 44g. The fourth pump P4 is a suction pump that draws ink from the gutter 16 to create a flow toward the seventh ink tube 44g.

[0204] A tenth valve V10 is disposed in the seventh ink pipe 44g between the gutter 16 and the fourth pump P4. The tenth valve V10 is an on-off valve that opens and closes the flow path of the seventh ink pipe 44g.

[0205] The printing ink in the ink tank 106 is sucked out by the sixth ink pipe 44f depending on the operating status of the third pump P3 and the open / close status of the fourteenth valve V14, and is ejected from the nozzle 12. The printing ink ejected from the nozzle 12 lands on the surface of the print substrate W during printing, and is collected by the gutter 16 when not printing. The latter printing ink is sucked out by the seventh ink pipe 44g depending on the operating status of the fourth pump P4 and the open / close status of the tenth valve V10, and is sent back to the ink tank 106. In this way, the printing ink circulates between the controller 100 and the print head 1.

[0206] -Fifth Route R5- Meanwhile, the solvent supply pipe 54, together with some elements of the ink supply pipe 44, constitutes a route (fifth route R5) for feeding the cleaning solvent from the solvent cartridge 51 to the nozzles 12.

[0207] 5, the fifth path R5 according to this embodiment is made up of a portion of the first solvent pipe 54a (the upstream end including the connection portion with the hollow solvent needle 53), the second solvent pipe 54b, and a portion of the sixth ink pipe 44f (the downstream end including the connection portion with the nozzle 12) in the solvent supply pipe 54. The second solvent pipe 54b connects the controller 100 and the print head 1.

[0208] The second solvent pipe 54b has one end connected to the first solvent pipe 54a between the hollow solvent needle 53 and the thirteenth valve V13, and the other end connected to the sixth ink pipe 44f between the fourteenth valve V14 and the nozzle 12. A second pump P2 is disposed midway along the second solvent pipe 54b in the solvent supply pipe 54. The second pump P2 is a suction pump that draws in the solvent to generate a flow from the hollow solvent needle 53 toward the solvent supply pipe 54 (particularly the second solvent pipe 54b).

[0209] A twelfth valve V12 is disposed in the second solvent pipe 54b between the second pump P2 and the nozzle 12. The twelfth valve V12 is an on-off valve that opens and closes the flow path of the second solvent pipe 54b in the solvent supply pipe 54.

[0210] Depending on the operating status of the second pump P2 and the open / close status of the twelfth valve V12, the solvent from the solvent cartridge 51 passes through the hollow solvent needle 53, the solvent reservoir 52, the first solvent pipe 54a, and the second solvent pipe 54b in that order, and is supplied to a portion midway through the sixth ink pipe 44f (the portion between the fourteenth valve V14 and the nozzle 12). The solvent supplied to this portion is ejected from the nozzle 12. This solvent cleans the print head 1.

[0211] The second solvent pipe 54b is connected to the cleaning nozzle 17. As described above, the cleaning nozzle 17 is capable of spraying a solvent as a cleaning liquid. A fifteenth valve V15 is provided between the cleaning nozzle 17 and the second solvent pipe 54b to control the supply of solvent to the cleaning nozzle 17.

[0212] - Sixth Route R6 - The solvent supply pipe 54 further constitutes a route (sixth route R6) for feeding the solvent from the solvent cartridge 51 to the ink supply pipe 44 and the ink hollow needle 43 via the junction 45.

[0213] As shown in FIG. 5 , the sixth path R6 in this embodiment is composed of a portion of the first solvent line 54a, a portion of the second solvent line 54b, and a third solvent line 54c in the solvent supply line 54. Note that the "portion of the first solvent line 54a" refers to the section from the solvent hollow needle 53 to the connection point B3 between the first solvent line 54a and the second solvent line 54b. The "portion of the second solvent line 54b" refers to the section from the connection point B3 between the first solvent line 54a and the second solvent line 54b to a position between the second pump P2 and the twelfth valve V12 (see connection point B4 in FIG. 5 ). The sixth path R6 branches off from the fifth path R5 downstream of the second pump P2. In this embodiment, the third solvent line 54c is disposed within the controller 100.

[0214] The third solvent pipe 54c has one end connected to the second solvent pipe 54b between the second pump P2 and the twelfth valve V12, and the other end connected to the junction 45.

[0215] The third solvent pipe 54c, together with the portion of the first solvent pipe 54a and the portion of the second solvent pipe 54b, constitutes a "solvent flow pipe" in this embodiment. When the solvent reservoir 52 receives the solvent cartridge 51, the third solvent pipe 54c flows the solvent in the solvent cartridge 51 to the junction 45 via the first solvent pipe 54a and the second solvent pipe 54b.

[0216] The second pump P2 is disposed in the second solvent pipe 54b that constitutes the solvent flow pipe. This second pump P2 can also be considered as a solvent pump that operates to generate a flow from the second solvent pipe 54b through the junction 45 and the first ink pipe 44a toward the ink hollow needle 43.

[0217] An eighteenth valve V18 is disposed in the second solvent pipe 54b between the junction 45 and the second pump P2. The eighteenth valve V18 is a second on-off valve that opens and closes the flow path of the second solvent pipe 54b.

[0218] -Paths Related to Ink Suction- The controller 100 also has paths related to ink suction. For example, the controller 100 has a suction path 47 connected to the nozzles 12. A sixth valve V6 is provided in the suction path 47. For example, when not printing, by operating the first pump P1 with the sixth valve V6 open, ink can be sucked through the suction path 47 and the sucked ink can be sent back to the controller 100.

[0219] <Details of the assist module 70> Figure 6 is a diagram illustrating the overall configuration of the assist module 70. Figure 7 is a perspective view illustrating the internal configuration of the print head 1. As already explained, the assist module 70 according to this embodiment is made up of an air generating unit 108 housed in the controller 100 and an assist unit 18 of the print head 1. This assist module 70 has a configuration suitable for the "air assist" described above.

[0220] -Air generating unit 108- The air generating unit 108 generates air to be sprayed from the air spraying unit 181 of the assisting unit 18. The air generating unit 108 is necessary when the assisting unit 18 performs "air assist." When the assisting unit 18 performs "mechanical assist," the air generating unit 108 is not essential.

[0221] The air generated by the air generating unit 108 and injected from the air injection unit 181 may be, for example, high-pressure air. The high-pressure air referred to here specifically refers to air at a pressure of 100 kPa or more and 300 kPa or more, and more specifically, air at a pressure of 150 kPa or more and 250 kPa or less. As an example, the air injection unit 181 according to this embodiment is configured to inject high-pressure air at a pressure of just under 200 kPa.

[0222] The air generating unit 108 may generate so-called dry air. As an example, the air generating unit 108 according to the present embodiment generates dry air, and the air spraying unit 181 pressurizes the dry air and sprays it.

[0223] Specifically, as shown in FIG. 5, the air generating unit 108 according to this embodiment has a first air pipeline 108a, an air filter 108b, an air pump 108c, a cooler 108d, a water separator 108e, a first pressure gauge 108f, an air dryer 108g, and a second pressure gauge 108h.

[0224] The first air pipeline 108a is a path through which air flows. In the first air pipeline 108a, an air filter 108b, an air pump 108c, a cooler 108d, a water separator 108e, a first pressure gauge 108f, an air dryer 108g, and a second pressure gauge 108h are arranged in this order from the upstream side.

[0225] The upstream end of the first air pipeline 108a is connected to an air tank disposed inside or outside the controller 100. The downstream end of the first air pipeline 108a is connected to the assist unit 18 via an umbilical cable 71. The umbilical cable 71 is bundled together with other pipelines into a connection cable 107.

[0226] The air filter 108b is a filter that removes foreign matter from the air. The air that passes through the air filter 108b then reaches the air pump 108c.

[0227] The air pump 108c is, for example, a diaphragm-type air pump built into the controller 100. The air pump 108c sucks in air that has passed through the air filter 108b and delivers it to the print head 1 via the cooler 108d, water separator 108e, etc. The air pump 108c is electrically connected to the control unit 101 and operates upon receiving a control signal from the control unit 101.

[0228] The cooler 108d cools the air whose temperature has risen due to the suction of the air pump 108c. The water separator 108e separates water from the air due to condensation caused by the suction of the air pump 108c. The cooler 108d is electrically connected to the control unit 101 and operates in response to control signals from the control unit 101.

[0229] The air dryer 108g is, for example, a hollow fiber membrane type air dryer that is built into the controller 100. The air dryer 108g generates dry air by drying the air that has passed through the water separator 108e. By building the air dryer 108g into the controller 100, the print head 1 can be made more compact.

[0230] The first pressure gauge 108f is disposed in the first air pipeline 108a at a position between the water separator 108e and the air dryer 108g. The first pressure gauge 108f detects the air pressure at that position. The first pressure gauge 108f is electrically connected to the control unit 101 and inputs a detection signal to the control unit 101. The control unit 101 determines whether the first air pipeline 108a is blocked or narrowed upstream of the air dryer 108g based on the detection signal from the first pressure gauge 108f.

[0231] The second pressure gauge 108h is disposed in a position downstream of the air dryer 108g in the first air pipeline 108a. The second pressure gauge 108h detects the air pressure at that position. The second pressure gauge 108h is electrically connected to the control unit 101 and inputs a detection signal to the control unit 101. Based on the detection signal from the second pressure gauge 108h, the control unit 101 determines whether there is a blockage or narrowing in the first air pipeline 108a downstream of the air dryer 108g, the umbilical cable 71, the air path (second air pipeline 18a) of the assist unit 18, the air injection unit 18c, etc.

[0232] The second pressure gauge 108h is disposed midway from the air dryer 108g to the assist unit 18, and exemplifies the "pressure sensor" in this embodiment in that it can detect air blockage.

[0233] In addition, the first pressure gauge 108f and the second pressure gauge 108h can also be used to determine the pressure of the air when the air injected from the assist unit 18 is pressurized.

[0234] - Assist unit 18 - The assist unit 18 injects dry air generated by the air generating unit 108. The assist unit 18 according to this embodiment is configured to be suitable for implementing "air assist." The same applies to the first modified example described below. When "mechanical assist" is implemented, the configuration and structure of the assist unit 18 will be changed, as in the second and third modified examples described below.

[0235] Specifically, the assist unit 18 according to this embodiment includes a second air pipeline 18a, an electromagnetic valve 18b, and an air injection unit 18c, as shown in Fig. 5. The electromagnetic valve 18b according to this embodiment corresponds to the "22nd valve V22" in Fig. 5.

[0236] The second air duct 18a is a path through which air flows. In the second air duct 18a, an electromagnetic valve 18b and an air ejection unit 18c are arranged in this order from the upstream side.

[0237] The upstream end of the second air pipeline 18a is connected to the downstream end of the umbilical cable 71. Dry air generated by the air generator 108 flows into the second air pipeline 18a via the umbilical cable 71.

[0238] The solenoid valve 18b is a control valve for controlling the injection of air generated by the air generating unit 108. The solenoid valve 18b is electrically connected to the control unit 101 and operates in response to a control signal received from the control unit 101. When the solenoid valve 18b operates, the second air pipe 18a, particularly the second air pipe 18a upstream of the air injection unit 18c, is opened or closed.

[0239] The air injection unit 18c injects air into the interior of the print head 1. For example, as shown in Figure 6, the air injection unit 18c is an air nozzle that injects dry air generated by the air generation unit 108. The air injection unit 18c as an air nozzle has an orifice 18d that can be opened and closed. This orifice 18d is electrically connected to the control unit 101, and opens and closes in response to a control signal from the control unit 101.

[0240] 4A and 7, the air ejection unit 18c according to this embodiment is located between the gutter 16 and the first electrode plate 151 in the up-down direction. In addition, the air ejection unit 18c is located at approximately the same position as the tip of the gutter 16 (the ink or solvent receiving port) and the first electrode plate 151 in the left-right direction.

[0241] 4A , the air ejection axis Aa of the air ejection unit 18c extends toward the deflection electrode 15, and more specifically, toward the second electrode plate 152. The "air ejection axis Aa" here refers to the central axis of the air ejected from the air ejection unit 18c. That is, the air ejection unit 18c according to this embodiment ejects air toward the deflection electrode 15, and particularly toward the second electrode plate 152.

[0242] More specifically, the air injection axis Aa of the air injection unit 18c intersects with the central axis Ax of the solvent axis, as illustrated in Fig. 4A. That is, the air injection unit 18c according to this embodiment is disposed so that the solvent axis ejected from the nozzle 12 is interposed between the air injection unit 18c and the deflection electrode 15, particularly the second electrode plate 152.

[0243] The control unit 101 operates the air pump 108c while the solenoid valve 18b or the orifice 18d is closed. This allows the dry air to be pressurized. When the solenoid valve 18b or the orifice 18d is opened while the dry air is pressurized, the dry air is sprayed from the air spray unit 18c.

[0244] As illustrated by the symbol M1 in Fig. 4B , the assist unit 18 applies air (dry air) injected from the air injection unit 18c to the solvent supplied from the solvent supply unit 105. By applying the dry air to the solvent, cleaning with the solvent is assisted.

[0245] 4A and 4B , as described above, the solvent shaft discharged from the nozzle 12 is interposed between the air ejection unit 18c and the second electrode plate 152. Therefore, as indicated by the symbol M1 in Fig. 4B , the assist unit 18 according to this embodiment can apply dry air to the shaft-shaped solvent (solvent shaft) discharged from the nozzle 12 or to droplets of solvent discharged from the nozzle 12.

[0246] More specifically, the assist unit 18 sprays air (dry air) from the air spray unit 18c onto the solvent supplied from the solvent supply unit 105, thereby turning the solvent into mist, as indicated by symbol M1 in FIG. 4B . The solvent is turned into mist by, for example, pressurizing the air. After hitting the solvent axis, the pressurized air collides with the second electrode plate 152. By causing the air to collide with the second electrode plate 152, dirt adhering to the second electrode plate 152 is more easily removed. Furthermore, by turning the solvent into mist, the area of ​​the parts cleaned by the solvent is expanded compared to when the solvent is not turned into mist.

[0247] The control unit 101 has a cleaning control unit 101a as a functional element for controlling head cleaning by the solvent supply unit 105 and the assist unit 18. The cleaning control unit 101a is an example of a "cleaning management unit" in this embodiment.

[0248] The cleaning control unit 101a, which functions as a cleaning management unit, manages the amount of solvent used during head cleaning so that the amount of solvent supplied corresponds to the amount of air sprayed from the air spray unit 18c, thereby preventing leakage of the solvent from the ejection ports 10a. This process is common to both the "air assist" and "mechanical assist" methods described below. The method for managing the amount of solvent used will be described in detail later.

[0249] The cleaning control unit 101a can also change the head cleaning sequence based on the detection signal from the attitude sensor 24. The sequence can be changed to change, for example, the amount of solvent supplied from the solvent supply unit 105. This prevents solvent from leaking from the print head 1, particularly from its housing 10.

[0250] Furthermore, the cleaning control unit 101a operates the shutter 21 to close the discharge openings 10a when assisting the assist unit 18. This prevents solvent from leaking from the print head 1, particularly from the housing 10 thereof.

[0251] Furthermore, when the discharge port 10a is closed by the shutter 21 during assist, the cleaning control unit 101a activates the suction device 22 to suck air from inside the print head 1 and exhaust it. This dries the inside of the print head 1 and volatilizes the solvent adhering to the inside of the print head 1. This prevents leakage of solvent from the print head 1, particularly from its housing 10. Note that although the shutter 21 is used to close the discharge port 10a here, it is not necessary to close the discharge port 10a with the shutter 21 if, for example, the suction device 22 is operating. In this case, even if a shutterless configuration is adopted, leakage of solvent from the housing 10 can be prevented.

[0252] The specific processing performed by the control unit 101 will be described in detail below.

[0253] <Specific Example of Processing> (Determining Whether Head Cleaning is Necessary) Fig. 8 is a flowchart illustrating a process for determining whether head cleaning is necessary. The process shown in Fig. 8 is performed by the control unit 101, for example, when the inkjet recording apparatus I recovers from an error state (when the error is recovered) and when an instruction to perform head cleaning is input via the operation display unit 103. In the process of Fig. 8, the orifice 18d may be opened or closed instead of or in addition to opening and closing the solenoid valve 18b.

[0254] First, in step SB1, the cleaning control unit 101a determines whether or not the inkjet recording apparatus I is in a printable state. A printable state refers to a state in which ink is circulating inside the inkjet recording apparatus I. The determination in step SB1 can be made based on, for example, a detection signal from the gutter sensor 16b.

[0255] If the determination in step SB1 is YES, the cleaning control unit 101a advances the control process to step SB2. On the other hand, if the determination in step SB1 is NO, the cleaning control unit 101a advances the control process to step SB3.

[0256] In step SB2, the cleaning control unit 101a stops the circulation of ink by stopping the supply of ink from the controller 100 to the print head 1. This also stops the ejection of ink from the nozzles 12. This process is executed, for example, by closing the fourteenth valve V14 in FIG.

[0257] In step SB3, the cleaning control unit 101a supplies solvent from the controller 100 to the print head 1, thereby starting the ejection of solvent from the nozzles 12. By performing step SB3, the solvent ejected from the nozzles 12 is collected by the gutter 16 at this stage. The processing of step SB3 is executed, for example, by opening the twelfth valve V12 in Figures 5 and 6.

[0258] Immediately thereafter, in step SB4, the cleaning control unit 101a stops the discharge of the solvent from the nozzle 12. The process of step SB4 is executed, for example, by closing the twelfth valve V12 in FIGS.

[0259] By performing steps SB3 and SB4 consecutively, the solvent is filled up to the solvent supply pipe 54 upstream of the twelfth valve V12, while the solvent is discharged from the solvent supply pipe 54 downstream of the twelfth valve V12. This allows the amount of solvent used during head cleaning to be managed. That is, it becomes possible to use as constant an amount of solvent as possible during head cleaning. This makes it possible to prevent solvent leakage from the discharge ports 10a during head cleaning.

[0260] The time interval from the completion of step SB3 to the start of step SB4 may be set within the range of 50 msec to 150 msec, for example.

[0261] In the following step SB5, the cleaning control unit 101a activates the air pump 108c (air pump: ON). In the following step SB6, the cleaning control unit 101a closes the solenoid valve 18b (solenoid valve: open → closed) and reads the pressure of the air generated by the air generator 108. The pressure detected by the first pressure gauge 108f, for example, can be used as the air pressure read here.

[0262] In the next step SB7, the cleaning control unit 101a determines whether the air pressure is normal or not based on the contents read in step SB6. This determination can be made based on whether the detected air pressure exceeds a predetermined reference value.

[0263] If the determination in step SB7 is YES, the cleaning control unit 101a advances the control process to step SB8. On the other hand, if the determination in step SB7 is NO, the cleaning control unit 101a advances the control process to step SB13. A possible cause of a NO determination in step SB7 is a clogged air filter 108b. Therefore, in step SB13, the cleaning control unit 101a makes an "error determination" that head cleaning cannot be performed normally, and displays instructions for cleaning the air filter 108b on the operation display unit 103 to eliminate the cause of the error.

[0264] In step SB8, the cleaning control unit 101a opens the electromagnetic valve 18b (electromagnetic valve: closed → open) and determines whether air is being ejected from the air ejection unit 18c. The determination of whether air is being ejected can be made based on a change in the detected pressure, for example, based on the detection signal of the first pressure gauge 108f.

[0265] In the next step SB9, the cleaning control unit 101a closes the electromagnetic valve 18b (electromagnetic valve: open → closed). In the next step SB10, the cleaning control unit 101a stops the air pump 108c (air pump: OFF). Note that the air pump 108c may be stopped, for example, when the pressure detected by the second pressure gauge 108h reaches a predetermined specified pressure.

[0266] In the next step SB11, the pressure of the air generated by the air generating unit 108 is read. The air pressure read here may be, for example, the pressure detected by the second pressure gauge 108h.

[0267] In the next step SB12, the cleaning control unit 101a determines whether the air pressure is normal or not based on the contents read in step SB11. This determination can be made based on the rate at which the detected air pressure decreases, i.e., the rate at which air escapes from the air injection unit 18c serving as an air nozzle.

[0268] If the determination in step SB12 is YES, the cleaning control unit 101a ends the control process illustrated in Fig. 8 and starts the control process illustrated in Fig. 9. On the other hand, if the determination in step SB12 is NO, the cleaning control unit 101a advances the control process to step SB13. Possible causes of a NO determination in step SB12 include, for example, a narrowing or blockage of the air path downstream of the air dryer 108g. Therefore, in step SB13, the cleaning control unit 101a makes an "error determination" that head cleaning cannot be performed normally, and displays instructions for cleaning the air path on the operation display unit 103 to eliminate the cause of the error.

[0269] (Specific Process of Head Cleaning) Fig. 9 is a flowchart illustrating a specific process of head cleaning. The process shown in Fig. 9 is performed continuously, for example, when the determination in step SB12 in Fig. 8 is YES.

[0270] 9, the orifice 18d may be opened or closed instead of or in addition to opening or closing the solenoid valve 18b. Also, instead of automatically opening and closing the shutter 21 as in steps SC1 and SC13 described below, the discharge port 10a may be manually opened and closed using the shutter 21 or a cap similar to the shutter 21.

[0271] First, in step SC1, the cleaning control section 101a operates the shutter 21 to close the discharge port 10a before the assist section 18 performs the assisting operation.

[0272] In the subsequent step SC2, the cleaning control unit 101a operates the solvent pump (second pump P2), thereby allowing the solvent to reach the solvent supply pipe 54 immediately upstream of the twelfth valve V12.

[0273] In the next step SC3, the cleaning control section 101a waits for a predetermined time to wait for the pressure of the solvent to increase.

[0274] In the next step SC4, the cleaning control unit 101a closes the electromagnetic valve 18b. If the electromagnetic valve 18b is already closed when proceeding to step SC4, the cleaning control unit 101a maintains the electromagnetic valve 18b in the closed state.

[0275] In the next step SC5, the cleaning control unit 101a activates the air pump 108c, which causes dry air to reach the second air pipe 18a immediately upstream of the solenoid valve 18b.

[0276] In the next step SC6, the cleaning control section 101a waits for a predetermined time until the pressure of the dry air increases.

[0277] In the next step SC7, the cleaning control unit 101a opens the solenoid valve 18b. As a result, the dry air that has reached the second air pipe 18a immediately upstream of the solenoid valve 18b is sprayed from the air spray unit 18c. At this time, the dry air is sprayed toward the second electrode plate 152 along the spray axis Aa in FIG. 4A .

[0278] In the next step SC8, the cleaning control unit 101a opens the twelfth valve V12 for a predetermined time, thereby supplying the solvent from the nozzle 12 for the predetermined time period.

[0279] The solvent supplied from the nozzle 12 into the print head 1 flows along the central axis Ax. As described above, this central axis Ax intersects with the ejection axis Aa. Therefore, the dry air ejected from the air ejection unit 18c along the ejection axis Aa collides with the solvent flowing along the central axis Ax. By pressurizing the dry air, the solvent that collides with the dry air is more reliably converted into mist.

[0280] The mist of solvent hits the second electrode plate 152. The second electrode plate 152 is cleaned by the solvent. Even if the solvent that hits the second electrode plate 152 turns into droplets, the droplets are guided away from the discharge port 10a by the bent surface 152c. This prevents the solvent from leaking from the discharge port 10a.

[0281] The valve opening time of the twelfth valve V12 in step SC8 is changed, for example, based on the detection signal of the attitude sensor 24. Changing the valve opening time based on the detection signal of the attitude sensor 24 is an example of "changing the cleaning sequence" in this embodiment.

[0282] For example, if the print head 1 has its discharge port 10a facing vertically downward, the dry air and the solvent can collide more reliably. In this case, the solvent is more reliably converted into mist, and the open time of the 12th valve V12 is relatively long to convert a larger amount of solvent into mist. On the other hand, if the print head 1 has its discharge port 10a facing horizontally or vertically upward, it is inconvenient to cause the dry air and the solvent to collide. In this case, it is also inconvenient to convert the solvent into mist, so the open time of the 12th valve V12 is relatively short to convert a smaller amount of solvent into mist.

[0283] Before proceeding from step SC8 to step SC9, the solvent supply is stopped by closing the twelfth valve V12. Stopping the solvent supply means stopping the cleaning process (head cleaning). Therefore, just before proceeding to step SC9, only the injection of dry air from the air injection unit 18c, or more generally, the assistance by the assist unit 18, is performed. By injecting dry air without the presence of a solvent, the second electrode plate 152 can be dried.

[0284] In this way, the cleaning control unit 101a of this embodiment is configured to perform a drying process to dry the inside of the print head 1 by having the assist unit 18 perform assistance when solvent is not being supplied from the solvent supply unit 105.

[0285] In step SC9, the cleaning control section 101a closes the electromagnetic valve 18b, thereby temporarily completing the air assist by the assist section 18.

[0286] In the next step SC10, the cleaning control unit 101a determines whether the number of times the cleaning process, which cleans the components (e.g., the second electrode plate 152) housed inside the print head 1 with solvent supplied from the solvent supply unit 105, and the air-assisted drying process have been performed has reached a predetermined number of repetitions. If the determination is NO, the cleaning control unit 101a returns the control process to step SC6. If the determination is YES, the cleaning control unit 101a advances the control process to step SC11. The number of repetitions may be stored in advance in the control unit 101.

[0287] That is, the cleaning control unit 101a according to this embodiment is configured to alternately perform the cleaning process and the drying process by turning on and off the solvent supply from the solvent supply unit 105 while performing assistance by the assist unit 18 until the number of times the cleaning process and the drying process are performed reaches the number of repetitions.

[0288] In the following step SC11, the cleaning control unit 101a stops the air pump 108c (air pump: OFF). In the following step SC12, the cleaning control unit 101a activates the suction device 22. The activation of the suction device 22 ventilates the interior of the print head 1, drying the interior. This drying evaporates the solvent. Activating the suction device 22 while the ejection ports 10a are closed by the shutter 21 contributes to drying the interior of the print head 1.

[0289] That is, the cleaning control unit 101 a according to this embodiment is configured to dry the inside of the print head 1 by the suction device 22 when the ejection port 10 a is closed by the shutter 21 .

[0290] In the following step SC12, the cleaning control section 101a opens the shutter 21. This completes the control process illustrated in FIG.

[0291] <Reduction of solvent consumption in this embodiment> In a typical continuous inkjet recording device, ink droplets continue to fly through the internal space of the print head. As a result, dirt easily accumulates inside the print head. The interior of the print head needs to be cleaned periodically.

[0292] Until now, print head cleaning (head cleaning) has been performed by the user either by spraying solvent into the print head themselves, or by placing the print head on a cleaning platform and automatically discharging solvent from a cleaning nozzle located inside the print head, as is well known.

[0293] However, if a large amount of dirt accumulates inside the print head after long-term use, whether the user cleans the head themselves or cleans the head using a cleaning nozzle, a large amount of solvent will be consumed.Furthermore, if a large amount of dirt accumulates, it is not easy to remove all of the dirt even if the head is cleaned.

[0294] Therefore, it is considered to wash the head frequently before a large amount of dirt accumulates, that is, before the dirt becomes difficult to remove. However, washing the head frequently increases the number of times the solvent is used, which ultimately results in consuming a large amount of solvent.

[0295] Consuming a large amount of solvent increases the frequency of solvent replenishment, which is inconvenient for improving the convenience of the inkjet recording apparatus.

[0296] The problem to be solved by the above-described embodiment is to reduce the amount of solvent consumed during head cleaning and improve the convenience of the inkjet recording apparatus. To address this problem, this embodiment uses the assist unit 18 to assist in head cleaning, as illustrated in Figures 4B and 9. The assistance provided by the assist unit 18 can reduce the amount of solvent consumed during head cleaning. This makes it possible to improve the convenience of the inkjet recording apparatus I.

[0297] 4B, the solvent supplied from the solvent supply unit 105 can be sprayed onto the components inside the print head 1 by air. Spraying the solvent onto the components makes it easier to remove dirt adhering to the components. This makes it possible to achieve a sufficient cleaning effect while reducing the amount of solvent consumed.

[0298] 4B, the solvent supplied from the solvent supply unit 105 can be atomized by air and then sprayed onto the components inside the print head. The atomization of the solvent contributes to expanding the cleaning area of ​​the components. This allows for a sufficient cleaning effect while reducing the amount of solvent consumed.

[0299] 8, the cleaning control unit 101a as a cleaning management unit manages the amount of solvent used. This, combined with the assistance of the assist unit 18 in cleaning, can further reduce the amount of solvent consumed.

[0300] 4B, the solvent supplied from the nozzle 12 can be sprayed onto components inside the print head 1 by air. In a typical continuous inkjet recording device, the amount of solvent discharged from the nozzle 12 can be precisely controlled. Precise control of the amount of solvent discharged contributes to reducing the amount of solvent consumed.

[0301] Furthermore, in general, stains caused by ink gradually accumulate on the deflection electrode 15 as the inkjet recording apparatus I is used repeatedly. In contrast, according to this embodiment, as described with reference to FIG. 4B , a solvent can be sprayed onto the deflection electrode 15, making it easier to remove stains adhering to the deflection electrode 15. This is advantageous in that a sufficient cleaning effect can be achieved while reducing the amount of solvent consumed.

[0302] Generally, a high voltage is applied to the ungrounded second electrode plate 152. In this case, charged ink is attracted to the second electrode plate 152 more than to the grounded first electrode plate 151. The second electrode plate 152 is more susceptible to accumulation of dirt than the first electrode plate 151.

[0303] In contrast, the air spraying unit 18c according to the embodiment sprays the solvent toward the second electrode plate 152 when assisting with the assist unit 18. This makes it possible to more reliably clean the second electrode plate 152, which is expected to be prone to accumulation of dirt.

[0304] 4A, by providing the second electrode plate 152 with a bent surface 152c, the flow direction of the air jetted toward the second electrode plate 152 can be guided in a direction away from the axial solvent. This allows the flow direction of the solvent carried by the air flow to be guided in a direction away from the axial solvent. This suppresses leakage of the solvent from the ink ejection orifices 10a, thereby improving the convenience of the inkjet recording apparatus I.

[0305] 6, by arranging the control valve (solenoid valve 18b) in the print head 1 and arranging the air generating unit 108 in the controller 100, the print head 1 can be made more compact by removing the air generating unit 108 from the print head 1. This makes it possible to improve the convenience of the inkjet recording apparatus I.

[0306] In addition, in order to promote the spraying of the solvent by air or to expand the cleaning area by turning the air into mist, it is possible to generate air at a higher pressure. However, if the air is pressurized by the air generating unit 108 in the controller 100, there is a concern that condensation may occur inside the controller 100.

[0307] In contrast, according to the embodiment, the air generating unit 108 generates dry air using the air dryer 108g, as illustrated in Fig. 6. By configuring the air generating unit 108 to generate dry air, it is possible to suppress the occurrence of condensation even if the air generating unit 108 is disposed inside the controller 100.

[0308] 6, the second pressure gauge 108h can detect blockage of the dry air after passing through the air dryer 108g, thereby improving the convenience of the inkjet recording apparatus I.

[0309] 4A, by providing the inkjet recording apparatus I with a suction device 22, it is possible to dry the internal space of the print head 1 and discharge the evaporated solvent, thereby improving the convenience of the inkjet recording apparatus I.

[0310] Furthermore, as explained with respect to step SC8 in FIG. 9, by changing the cleaning sequence depending on the posture of the print head 1, the convenience of the inkjet recording apparatus I can be improved.

[0311] Furthermore, as illustrated in FIG. 4A, by providing a shutter 21 that opens and closes the discharge port 10a, leakage of the solvent from the discharge port 10a can be suppressed, and the convenience of the inkjet recording apparatus I can be improved.

[0312] Furthermore, as illustrated in step SC1 of Figure 9, by closing the discharge port 10a before the start of assist, leakage of solvent from the discharge port 10a can be more reliably suppressed, thereby improving the convenience of the inkjet recording device I.

[0313] Furthermore, as illustrated in step SC12 of Figure 9, by drying the inside of the print head 1 with the ejection port 10a closed, leakage of solvent from the ejection port 10a can be more reliably suppressed, thereby improving the convenience of the inkjet recording device I.

[0314] 9, by blowing air onto the components (e.g., the second electrode plate 152) when the solvent is not being supplied, it is possible to dry the components inside the print head 1. This improves the convenience of the inkjet recording apparatus I.

[0315] 9, by alternately repeating the cleaning process and the drying process, the head can be cleaned while drying the solvent each time, which further reliably prevents the solvent from leaking and improves the convenience of the inkjet recording apparatus I.

[0316] <First Modification of Inkjet Recording System S> Figure 10A is a diagram corresponding to Figure 4A, showing a first modification of the inkjet recording system S, and Figure 10B is a diagram corresponding to Figure 4B, showing a first modification of the inkjet recording system S. Figure 11 is a diagram illustrating the internal structure of the print head 1 according to the first modification. In Figures 10A, 10B, and 11, elements having the same configuration and structure as those in the previous embodiment are denoted by the same reference numerals as those in the previous embodiment.

[0317] The print head 1 according to the first modification includes a cleaning nozzle 17 arranged in the same manner as in the previous embodiment. As shown by reference symbol L2 in Figure 10B, the solvent ejected from the cleaning nozzle 17 is sprayed onto at least the nozzle 12. This allows the nozzle 12 to be cleaned. Cleaning the nozzle 12 allows the solvent to be ejected smoothly from the nozzle 12 during head cleaning.

[0318] In addition, the print head 1 of the first modified example, like the above embodiment, has an assist unit 318 that assists in cleaning the parts housed inside the print head 1 with solvent supplied from the solvent supply unit 105.

[0319] This assist unit 318 injects dry air generated by the air generating unit 108 similar to that of the above embodiment into the interior of the print head 1. In other words, the assist unit 318 according to the first modified example performs "air assist" similar to that of the above embodiment.

[0320] Specifically, the assist unit 318 according to the first modified example has a second air pipeline 18a and an electromagnetic valve 18b configured in the same manner as in the above embodiment, and an air injection unit 318c having a configuration unique to the first modified example.

[0321] The air injection unit 318c injects air into the interior of the print head 1. For example, as shown in Figure 6, the air injection unit 318c is an air nozzle that injects dry air generated by the air generation unit 108, and is configured in the same manner as in the previous embodiment in that it opens and closes in response to a control signal from the control unit 101.

[0322] 10A, 10B, and 11, the air ejection unit 318c according to the first modified example is disposed on the first electrode plate 151 so as to eject air toward the second electrode plate 152. The air ejection unit 318c is embedded in the first electrode plate 151 and opens to the first opposing surface 151a.

[0323] 10B , the air ejection axis Aa′ of the air ejection unit 318c extends toward the deflection electrode 15, more specifically, toward the second opposing surface 152a of the second electrode plate 152. That is, the air ejection unit 318c according to the first modified example ejects air toward the deflection electrode 15, particularly toward the second opposing surface 152a of the second electrode plate 152.

[0324] 10A , the air injection axis Aa′ of the air injection unit 318c extends obliquely upward and intersects with the central axis Ax of the solvent axis. That is, similar to the above embodiment, the air injection unit 318c according to the first modified example is disposed so that the solvent axis ejected from the nozzle 12 is interposed between the air injection unit 318c and the deflection electrode 15, particularly the second electrode plate 152.

[0325] The control unit 101 operates the air pump 108c while the solenoid valve 18b or the orifice 18d is closed. This allows the dry air to be pressurized. When the solenoid valve 18b or the orifice 18d is opened while the dry air is pressurized, the dry air is sprayed from the air spray unit 318c.

[0326] 10B , the assist unit 318 applies air (dry air) injected from the air injection unit 318c to the solvent supplied from the solvent supply unit 105. By applying the dry air to the solvent, cleaning with the solvent is assisted.

[0327] 10A and 10B , as described above, the solvent shaft ejected from the nozzle 12 is interposed between the air ejection unit 318c and the second electrode plate 152. Therefore, as indicated by the symbol M2 in Fig. 10B , the assist unit 318 according to the first modified example can apply dry air to the shaft-shaped solvent (solvent shaft) ejected from the nozzle 12 or to droplets of solvent ejected from the nozzle 12.

[0328] More specifically, the assist unit 318 sprays air (dry air) from the air spray unit 318c onto the solvent supplied from the solvent supply unit 105, thereby turning the solvent into mist, as indicated by the symbol M2 in FIG. 10B. The solvent is turned into mist by, for example, increasing the pressure of the air. By turning the solvent into mist, the area of ​​the parts that is washed by the solvent is expanded compared to when the solvent is not turned into mist.

[0329] The control unit 101 has a cleaning control unit 101a as a functional element for controlling head cleaning by the solvent supply unit 105 and the assist unit 318. The configuration of the cleaning control unit 101a is the same as that of the above embodiment.

[0330] <Significance of the First Modification> In a typical continuous inkjet recording device, ink droplets continue to fly through the internal space of the print head. As a result, dirt easily accumulates inside the print head. The interior of the print head needs to be cleaned periodically.

[0331] Until now, print head cleaning (head cleaning) has been performed by the user either by spraying solvent into the print head themselves, or by placing the print head on a cleaning platform and automatically discharging solvent from a cleaning nozzle located inside the print head, as is well known.

[0332] However, all of the head cleaning methods described above require the print head to be removed from the production line (corresponding to the conveying line L in this specification). For example, if the user is to manually clean the print head, they must remove the print head and then move it to a location where a solvent tray is located.

[0333] On the other hand, in the case of automatic cleaning in which the solvent is ejected in automatic droplets, after removing the print head, it is necessary to move the print head to a location where a mounting table (also called a cleaning table, cleaning mounting section, or cleaning station) that receives the solvent is located.

[0334] This process of removing the print head from the production line, moving it to a cleaning location, and then reinstalling it in its original position after cleaning is not only time-consuming, but also poses the risk of the print head falling during the process. Furthermore, frequent shutdowns of the production line could lead to a decrease in printing takt time. There were also concerns about securing personnel for such installation work and training those personnel.

[0335] The problem to be solved by the first modified example is to improve the usability of the inkjet recording apparatus by making it possible to clean the print head without removing it from the production line.

[0336] To address these issues, the first modified example reduces the amount of solvent consumed in head cleaning by using the assist unit 18 to assist in head cleaning. This reduces solvent leakage from the print head 1. By reducing solvent leakage, it becomes possible to clean the head with solvent without using a solvent tray, dedicated mounting table, or the like. This makes it possible to clean the print head 1 without removing it from the production line.

[0337] 10B, the solvent supplied from the solvent supply unit 105 is atomized by air and then sprayed onto the components inside the print head 1. The atomization of the solvent contributes to expanding the cleaning area of ​​the components. This makes it possible to ensure sufficient cleaning performance even with a small amount of solvent. In other words, regardless of the orientation of the print head 1, specific components (e.g., the second electrode plate 152) can be reliably cleaned while suppressing solvent leakage from the print head 1. This improves the usability of the inkjet recording apparatus I.

[0338] In particular, by configuring the print head 1 so that cleaning ability is ensured and solvent leakage is suppressed regardless of the position of the print head 1, it is possible to increase the degree of freedom in installing the print head 1. This makes it possible to improve the usability of the inkjet recording apparatus I.

[0339] Other features for suppressing solvent leakage from the nozzle 10a and reducing the amount of solvent used, such as adjusting the flow direction of the mist using the bent surface 152c and managing the amount of solvent used by the cleaning control unit 101a as a cleaning management unit, all contribute to making it possible to clean the print head 1 without removing it from the production line, and ultimately to improving the usability of the inkjet recording device I.

[0340] 10A and 11, by arranging the air injection unit 18c on the first electrode plate 151, the air injection unit 18c can be brought as close as possible to the axial solvent. This makes it possible to more reliably spray the solvent, which is advantageous for achieving a sufficient cleaning effect while reducing the amount of solvent consumed. Furthermore, arranging the air injection unit 18c on the first electrode plate 151 also contributes to making the print head 1 more compact.

[0341] 8, the cleaning control unit 101a is configured to manage the amount of solvent used, but instead of this configuration, the shutter 21 and the suction device 22 as in the above embodiment may be used. By using at least one of the management of the amount of solvent used, the shutter 21, and the suction device 22, leakage of the solvent from the discharge port 10a can be suppressed.

[0342] <Second Modification of Inkjet Recording System S> In the above embodiment and the first modification, "air assist" using air and solvent ejected from the nozzle 12 are used, but the use of these is not essential. Cleaning may be mechanically assisted without using air, and when such assistance is provided, solvent ejected from the cleaning nozzle 17 may be used instead of the solvent ejected from the nozzle 112.

[0343] Fig. 12 is a diagram corresponding to Fig. 4A and showing a second modified example of the inkjet recording system S. Figs. 13A and 13B are diagrams illustrating the operation of the assist unit 418 according to the second modified example. In Figs. 12, 13A, and 13B, elements having the same configurations and structures as those in the previous embodiment are denoted by the same reference numerals as those in the previous embodiment.

[0344] The print head 1 according to the second modification includes a cleaning nozzle 17 that sprays solvent, similar to the previous embodiment. As shown by reference symbol L3 in Fig. 13A, the solvent sprayed from the cleaning nozzle 17 is sprayed onto at least the deflection electrode 15. This allows the deflection electrode 15 to be cleaned with the solvent supplied from the cleaning nozzle 12 during assisted head cleaning.

[0345] The print head 1 of the second modified example, like the above embodiment and the first modified example, has an assist section 418 that assists in cleaning the parts housed inside the print head 1 with solvent supplied from the solvent supply section 105.

[0346] Unlike the above embodiment and the first modified example, this assist unit 418 has a contact unit 418c that is located inside the print head 1 and that mechanically contacts components housed inside the print head 1. In other words, unlike the above embodiment and the first modified example, the assist unit 418 according to the second modified example performs "mechanical assist."

[0347] Specifically, the assisting portion 418 according to the second modified example has a rail member 418a, a moving member 418b, and a contact portion 418c.

[0348] The rail member 418a extends in the vertical direction as shown by the chain line in FIG. 13A.

[0349] The moving member 418b moves up and down along the central axis of the rail member 418a when driven in response to a control signal received from the controller 100. A direct-acting stepping motor, for example, may be used as the power source for the moving member 418b.

[0350] The moving member 418b rotates 180° relative to the rail member 418a upon receiving a control signal from the controller 100. The rotation axis Ar of the moving member 418b is as shown by the chain line in FIG.

[0351] The gutter 16 and a contact portion 418c are attached to the moving member 418b so as to move integrally with the moving member 418b. The contact portion 418c is attached to the moving member 418b on the opposite side (particularly the opposite side in the left-right direction) from the gutter 16. Note that in the second modified example, it is not essential that the moving member 418b and the gutter 16 move integrally.

[0352] By rotating the moving member 418b relative to the rail member 418a, it is possible to switch between a state in which the tip of the gutter 16 faces the nozzle 12 as shown in Fig. 12 and a state in which the contact portion 418c faces the nozzle 12 as shown in Fig. 13B. Hereinafter, the former state will be referred to as the first state, and the latter state will be referred to as the second state.

[0353] In the second state, the contact portion 418c contacts at least one of the nozzle 12, the charging electrode 13, and the deflection electrode 15.

[0354] Furthermore, at least in the second and third modified examples, the solvent ejected from the cleaning nozzle 17 is configured to be sprayed onto at least one of the nozzle 12, the charging electrode 13, and the deflection electrode 15. The component onto which the solvent ejected from the cleaning nozzle 17 is sprayed and the component with which the contact portion 418c comes into contact are configured to at least partially overlap each other. In this example, the solvent is sprayed onto the first electrode plate 151, and the contact portion 418c comes into contact with the first electrode plate 151.

[0355] 13A , when the inkjet recording apparatus I is in a non-printable state (a state in which ink is not circulated), the control unit 101 sets the moving member 418b to the first state and then moves the moving member 418b upward until it comes into close contact with the nozzle 12. By bringing the gutter 16 and the nozzle 12 into close contact with each other, drying of the nozzle 12 is suppressed.

[0356] Thereafter, the control unit 101 causes the cleaning nozzle 17 to eject the solvent, thereby spraying the solvent onto at least one of the nozzle 12, the charging electrode 13, and the deflection electrode 15 (for example, the first electrode plate 151). The components onto which the solvent is sprayed become wet with the solvent.

[0357] Thereafter, the control unit 101 sets the moving member 418b in the second state and moves it downward, thereby bringing at least one of the nozzle 12, the charging electrode 13, and the deflecting electrode 15 (for example, the first electrode plate 151) into contact with the contact portion 418c, as shown in Fig. 13B.

[0358] In this way, the assisting part 518 brings the contacting part 418c into contact with the component wetted with the solvent supplied from the solvent supplying part 105, specifically the cleaning nozzle 17. This contact assists cleaning with the solvent.

[0359] 13A and 13B , the assist unit 418 moves the contact portion 418c downward while keeping the contact portion 418c in contact with the first electrode plate 151. By moving the contact portion 418c, the solvent supplied from the solvent supply unit 105 is wiped off the contact portion 418c. Wiping off the solvent makes it easier to remove dirt adhering to the first electrode plate 151. Furthermore, by moving the contact portion 418c, the area of ​​the component cleaned by the solvent is expanded compared to when the contact portion 418c is not moved.

[0360] The control unit 101 has the cleaning control unit 101a described above as a functional element for controlling head cleaning by the solvent supply unit 105 and the assist unit 18. The function performed by the cleaning control unit 101a is the same as in the above embodiment.

[0361] That is, the cleaning control unit 101a, which functions as a cleaning management unit, manages the amount of solvent used during cleaning so that the surfaces of the components are wetted with the solvent supplied from the solvent supply unit 105. Unlike the "air assist" method, this management is achieved by controlling the opening and closing times of the 15th valve V15.

[0362] The cleaning control unit 101a can also change the head cleaning sequence based on the detection signal from the attitude sensor 24. The sequence can be changed to change, for example, the amount of solvent supplied from the solvent supply unit 105. This prevents solvent from leaking from the print head 1, particularly from its housing 10.

[0363] <Significance of the Second Modification> As described above, according to the second modification, the assist unit 418 assists in head cleaning, as illustrated in Fig. 13B. The amount of solvent consumed in head cleaning can be reduced by the amount of assistance provided by the assist unit 418. This can improve the convenience of the inkjet recording apparatus I.

[0364] 13B, the contact portion 418c can be used to rub the solvent supplied from the solvent supply unit 105 onto components (e.g., the first electrode 151) within the print head 1. Rubbing the solvent onto the components makes it easier to remove dirt adhering to the components. This makes it possible to achieve a sufficient cleaning effect while reducing the amount of solvent consumed.

[0365] 13A and 13B, the contact portion 418c can wipe the solvent supplied from the solvent supply unit 105 from the components inside the print head 1. Wiping off the solvent contributes to expanding the cleaning area of ​​the components. This makes it possible to achieve a sufficient cleaning effect while reducing the amount of solvent consumed.

[0366] Furthermore, the cleaning control unit 101a, which serves as a cleaning management unit, controls the amount of solvent used by controlling the opening and closing time of the fifteenth valve V15. This, combined with the assistance of the assist unit 418 in cleaning, can further reduce the amount of solvent consumed.

[0367] <Third Modification of Inkjet Recording System S> The above-described embodiment, the first modification, and the second modification have all been configured to include an assist unit 18, 318, 418 as an element of the print head 1, but the present disclosure is not limited to such a configuration.

[0368] The assist unit according to the present disclosure may be configured as a separate member from the print head 1, or even from the inkjet recording apparatus I. Such a configuration will be described with reference to Figures 14 and 15. Figure 14 is a diagram corresponding to Figure 1, showing a third modified example of the inkjet recording system S. Figure 15 is a diagram corresponding to Figure 4A, showing a third modified example of the inkjet recording system S. In Figures 14 and 15, elements having the same configuration and structure as those in the previous embodiment are denoted by the same reference numerals as those in the previous embodiment.

[0369] As shown in Fig. 14, the inkjet recording system S according to the third modified example comprises an inkjet recording apparatus I and a cleaning apparatus 1000. The inkjet recording apparatus I is a continuous type inkjet recording apparatus comprising a print head 1 and a controller 100, and performs printing by causing ink ejected from the print head 1 to land on a print target W. The controller 100, similar to the configuration described using Fig. 2, comprises an ink supply unit 104 and an assist unit 518. On the other hand, as shown in Fig. 15, the cleaning apparatus 1000 is attached to the print head 1 and has an assist unit 518 that assists in cleaning of the components housed inside the print head 1 with solvent supplied from a solvent supply unit 105 (not shown).

[0370] The print head 1 of the third modified example, like the above embodiment and the first modified example, has an assist section 518 that assists in cleaning the parts housed inside the print head 1 with solvent supplied from the solvent supply section 105.

[0371] The assisting section 518 according to the third modification has a rail member 518a, a moving member 518b, and a contacting section 518c. The assisting section 518 performs "mechanical assist" in the same manner as the second modification.

[0372] The assisting unit 518 according to the third modification brings the contacting portion 518c into contact with the component wetted with the solvent supplied from the solvent supplying unit 105, specifically, the cleaning nozzle 17. The assisting unit 518 assists in cleaning with the solvent by bringing the contacting portion 518c into contact with the wetted component.

[0373] 14 is merely an example. The print head 1 may be removed from the transport line L, transported to a cleaning device 1000 located at a specific location, and then installed there.

[0374] 15 is merely an example. As in the above-described embodiment and the first modified example, the cleaning device 1000 may perform "air assist."

[0375] While Figure 5 illustrates the paths of ink and solvent, Figure 16 shows a flow path diagram that extracts elements related to cleaning the print head 1 from Figure 5. In the flow path diagram shown in Figure 16, the controller 100 has an ink tank 106, which is a supply source of viscosity-adjusted ink liquid. This ink tank 106 contains quick-drying ink liquid. The ink tank 106 can also be called the "main tank." The ink liquid in the ink tank 106 is supplied to the print head 1 by a third pump (ink pump) P3.

[0376] The controller 100 also has a solvent cartridge 51, which is a solvent supply source. This solvent cartridge 51 contains, for example, methyl ethyl ketone (MEK). The solvent in the solvent cartridge 51 is supplied to the print head 1 by a second pump (solvent pump) P2. An open / close solvent solenoid valve V16 (not shown in FIG. 5) is located downstream of this second pump P2. When there is no need to supply solvent to the print head 1, the solvent solenoid valve V16 is closed.

[0377] The controller 100 has a first pump (suction pump or circulation pump) P1 that recovers ink liquid that has dripped into the gutter and returns it to the ink tank 106. When the print head 1 is cleaned during shutdown processing, the first pump P1 is operated to recover cleaning liquid (solvent) from the print head 1 into the ink tank 106. Instead of recovering this cleaning liquid into the ink tank 106, the cleaning liquid may be recovered into a conventionally known conditioning tank (not shown) that is installed in the controller 100 separately from the ink tank 106.

[0378] The print head 1 has an ink line 360 ​​that receives ink from the ink tank 106, and a solvent line 362 that receives cleaning liquid (solvent) from the solvent cartridge 51. A fourteenth valve V14 is installed in the ink line 360. A twelfth valve V12 is installed in the solvent line 362. The ink line 360 ​​and the solvent line 362 join at their downstream ends to form a supply path 350. Reference symbol P in the figure indicates the joining point. This supply path 350 reaches the discharge port 12a of the nozzle 12. The nozzle discharge port 12a also communicates with a suction path 352, which is connected to the first pump P1 described above.

[0379] By opening the fourteenth valve V14, the ink liquid in the ink tank 106 is supplied to the supply path 350. On the other hand, by opening the twelfth valve V12, the solvent (cleaning liquid) in the solvent cartridge 51 is supplied to the supply path 350.

[0380] The supply path 350 and the suction path 352 are configured with tubes except for the nozzle 12. These tubes may be configured with PTFE tubes as in the past, but it is preferable to configure them with PFA tubes having the same diameter as in the past. PFA tubes have less surface roughness and superior water repellency compared to PTFE tubes. These characteristics make it easier for the cleaning solution to form a film inside the PFA tube.

[0381] A sixth valve V6 is provided in the suction path 352 (suction path 47), and by opening this sixth valve V6, the ink liquid and solvent in the print head 1 are collected into the ink tank 106 by the first pump P1.

[0382] The print head 1 has a cleaning nozzle 17 for cleaning the nozzles 12 of the print head 1. As described above, the cleaning nozzle 17 is used to clean the nozzle outlets 12a and the like by spraying a cleaning liquid (solvent) from the cleaning nozzle 17. Specifically, the cleaning nozzle 17 may be positioned inside the print head 1 so as to face the nozzle outlets 12a, or may be positioned so as to face the charging electrode 13 or the deflection electrode 15. The cleaning nozzle 17 is in communication with the solvent cartridge 51 via an openable and closable fifteenth valve V15. When cleaning the nozzles 12, the twelfth valve V12 and the fifteenth valve V15 are both opened, and the solvent supplied from the solvent cartridge 51 is sprayed from the cleaning nozzle 17.

[0383] Alternatively, air may be sucked through the cleaning nozzle 17 to dry the nozzle 12. Specifically, the solvent solenoid valve V16 and the fourteenth valve V14 may be closed, the twelfth valve V12 and the sixth valve V6 may be opened, and the first pump P1 may be operated to send air as shown by the arrows in FIG. 16. This can speed up the drying of the nozzle 12. In this way, the cleaning nozzle 17 may have both the function of discharging solvent and the function of sucking air.

[0384] S Inkjet recording system I Inkjet recording device 1 Print head 10 Housing 10a Discharge port 12 Nozzle 13 Charging electrode 15 Deflection electrode 151 First electrode plate 151a First opposing surface 152 Second electrode plate 152a Second opposing surface 152b Inclined surface 152c Bent surface 16 Gutter 17 Cleaning nozzle 18 Assisting section 18c Air spraying section 21 Shutter 22 Aspirator (suction section, drying section) 24 Posture sensor 318 Assisting section 318c Air spraying section 418 Assisting section 418c Contacting section 518 Assisting section 518c Contacting section 100 Controller 101 Control section 101a Cleaning control section (cleaning management section) 104 Ink supplying section 105 Solvent supplying section 108 Air generating section 18b Solenoid valve (control valve) 108g Air dryer 108h Second pressure gauge (pressure sensor) 1000 Cleaning device W Printing object As Solvent axis

Claims

1. A continuous type inkjet recording device comprising: a print head which houses within it a nozzle which ejects particulate ink, a charging electrode which charges the particulate ink ejected from the nozzle, a deflection electrode which deflects the flight direction of the ink charged by the charging electrode, and a gutter which collects the ink undeflected by the deflection electrode, and which ejects the ink deflected by the deflection electrode to the outside; an ink supply unit which supplies ink to the print head; a solvent supply unit which supplies solvent to the print head; and a control unit which controls the supply of ink from the ink supply unit to the print head and also controls the supply of solvent from the solvent supply unit to the print head, wherein the inkjet recording device performs printing by causing the ink ejected from the print head to land on a print object, wherein the print head has an assist unit which assists in cleaning of parts housed inside the print head with the solvent supplied from the solvent supply unit.

2. An inkjet recording device according to claim 1, wherein the assist section includes an air injection section which injects air into the interior of the print head, and assists the cleaning by directing the air injected from the air injection section against the solvent supplied from the solvent supply section.

3. An inkjet recording device as described in claim 2, characterized in that the assist unit expands the area of ​​the part that is cleaned by the solvent by directing air sprayed from the air spray unit against the solvent supplied from the solvent supply unit to turn the solvent into mist.

4. An inkjet recording device as described in claim 2, wherein the print head has an ink ejection port for ejecting ink deflected by the deflection electrode to the outside, and the control unit has a cleaning management unit that manages the amount of solvent used during cleaning so that an amount of solvent corresponding to the air ejected from the air ejection unit is supplied.

5. An inkjet recording device as described in claim 1, wherein the assist unit has a contact portion located inside the print head and mechanically contacts the component, and assists the cleaning by bringing the contact portion into contact with the component wetted by the solvent supplied from the solvent supply unit.

6. An inkjet recording apparatus as described in claim 5, characterized in that the assist unit expands the area of ​​the part that is cleaned by the solvent by contacting the contact unit with the solvent supplied from the solvent supply unit and wiping off the solvent.

7. An inkjet recording apparatus according to claim 5, wherein the control unit has a cleaning management unit that manages the amount of solvent used during cleaning so that the surface of the part is wetted with the solvent supplied from the solvent supply unit.

8. An inkjet recording device as claimed in any one of claims 2 to 4, characterized in that the air injection section is arranged to inject air towards the deflection electrode and to interpose an axial-shaped solvent ejected from the nozzle between the air injection section and the deflection electrode.

9. An inkjet recording device as described in claim 8, characterized in that the deflection electrode is composed of first and second electrode plates facing each other, and the air injection section is disposed on the first electrode plate so as to inject air toward the second electrode plate.

10. An ink jet recording apparatus according to claim 9, wherein the first electrode plate is grounded.

11. An inkjet recording device as described in claim 10, wherein the print head has an ink ejection port for ejecting ink deflected by the deflection electrode to the outside, and the second electrode plate has an inclined surface inclined in a direction away from the axial solvent, and a bent surface extending from the tip of the inclined surface on the ink ejection port side and bending more steeply than the inclined surface in a direction away from the axial solvent.

12. An inkjet recording device as claimed in any one of claims 2 to 4, further comprising a controller that houses the ink supply unit, the solvent supply unit and the control unit therein, the controller further having an air generating unit that generates air to be sprayed from the air spray unit, and the assist unit having a control valve for controlling the spray of air generated by the air generating unit.

13. An inkjet recording apparatus according to claim 12, wherein said air generating section has an air dryer in said controller for generating dry air by drying air.

14. The inkjet recording apparatus according to claim 13, further comprising a pressure sensor arranged midway from said air dryer to said assist section for detecting air blockage.

15. An inkjet recording device as claimed in claim 1, characterized in that said print head has an ink ejection port for ejecting ink deflected by said deflection electrode to the outside, and a shutter for opening and closing said ink ejection port.

16. An inkjet recording apparatus according to claim 15, wherein said control section operates said shutter to close said ink ejection port before assistance is provided by said assist section.

17. An ink jet recording apparatus according to claim 15 or 16, further comprising a drying section for drying the inside of said print head when said ink ejection port is closed by said shutter.

18. An inkjet recording device as claimed in any one of claims 2 to 7, characterized in that the control unit performs a drying process to dry the inside of the print head by causing the assist unit to perform assistance when solvent is not being supplied from the solvent supply unit.

19. An inkjet recording apparatus according to claim 18, characterized in that the control unit alternately performs a cleaning process in which the parts are cleaned with the solvent supplied from the solvent supply unit and the drying process by performing assistance by the assist unit while turning on and off the solvent supply from the solvent supply unit.

20. An inkjet recording system comprising: a print head containing a nozzle for ejecting particulate ink, a charging electrode for charging the particulate ink ejected from the nozzle, a deflection electrode for deflecting the flight direction of the ink charged by the charging electrode, and a gutter for collecting ink undeflected by the deflection electrode, and ejecting the ink deflected by the deflection electrode to the outside; an ink supply unit for supplying ink to the print head, a solvent supply unit for supplying solvent to the print head, and a control unit for controlling the supply of ink from the ink supply unit to the print head and the supply of solvent from the solvent supply unit to the print head, and comprising: a continuous type inkjet recording device which performs printing by causing the ink ejected from the print head to land on a print target; and a cleaning device which is attached to the print head and has an assist unit for assisting in cleaning of parts contained inside the print head with the solvent supplied from the solvent supply unit.

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