Refill cartridges and ink cartridges

Abstract

To suppress ink peeling due to adhesion of alcohol after drying and prevent apparatus malfunctions caused by changes in a component ratio of a mixed solvent even when viscosity adjustment of the ink with the mixed solvent is repeatedly performed in the apparatus.SOLUTION: An ink jet recording apparatus receives ink containing a solvent in which ketone and alcohol having higher volatility than the ketone are mixed, an ink colorant, and a binder, and also receives a replenishment liquid containing the ketone and the alcohol having the higher volatility than the ketone. The ink contains 15 mass% or more of solids including the ink colorant and the binder. The ketone is one or more selected from the group consisting of diethyl ketone, methyl isopropyl ketone, and methyl propyl ketone. The mass percent concentration of the ketone in the replenishment liquid is lower than the mass percent concentration of the ketone in the solvent of the ink.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an inkjet recording apparatus that prints on a print target, for example, an ink for the inkjet recording apparatus, a replenisher liquid for the inkjet recording apparatus, and a combination of the ink and the replenisher liquid. [Background technology]

[0002] For example, Patent Document 1 discloses a so-called continuous inkjet recording device for printing on a print medium, which circulates ink inside the device even when not printing on the print medium. This continuous inkjet recording device is configured to charge ink droplets ejected from an ejection head, deflect the flight direction (travel direction) of the charged ink using electrodes, and eject the deflected ink droplets to the outside to perform printing. Ink droplets not used in printing are collected via a collection path and reused.

[0003] Patent Document 1 also discloses an ink composition for use in the inkjet recording device, which contains a binder, a dye or pigment, and a solvent. The solvent contains an organic compound such as an acyclic acetal, such as ethylal, methylal, acetal, or dimethyl acetal, and a low-molecular-weight alcohol (such as a ketone). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2010-518214 Summary of the Invention [Problem to be solved by the invention]

[0005] In a continuous-type inkjet recording device, air is sucked into a recovery path along with ink particles not used in printing, and the sucked air is then discharged to the outside through an exhaust port. As disclosed in Patent Document 1, the ink composition contains a solvent that is volatile at room temperature. The air sucked into the recovery path also contains a large amount of this solvent component, and the air containing this solvent component is discharged from the device. As a result, over time, the solvent component in the tank storing the ink decreases, causing the ink viscosity to increase, which can lead to printing defects. Therefore, the viscosity of the ink in the tank is constantly measured, and the tank is replenished with a replenisher liquid with a lower viscosity than the ink in the tank to maintain the ink viscosity within a predetermined range, thereby adjusting the viscosity of the ink in the tank.

[0006] On the other hand, there is a demand for inks used in continuous inkjet recording devices to have high functionality in terms of adhesion, quick drying, conductivity, stability, etc. For example, when printing on a print target and then disinfecting the print target with disinfectant alcohol, even if the alcohol adheres to the printed surface, there is a demand to minimize dissolution of the ink and peeling of the print. Furthermore, various ink solvents are selected in consideration of ease of handling, availability, cost-effectiveness, etc. For example, among solvents not subject to regulations such as the Organic Solvent Poisoning Prevention Regulations (solvents not subject to the Organic Solvent Regulations), inks selected from solvents such as methyl isopropyl ketone, methyl propyl ketone, diethyl ketone, etc. mixed with ethanol (inks with mixed solvents of two or more components) can be used. Furthermore, other options include selecting ink solvents based on the characteristics of the ink's solid content or selecting ink solvents with high allowable concentrations that indicate exposure limits.

[0007] Examples of solvents that are not subject to the Organic Solvent Law include methyl isopropyl ketone, methyl propyl ketone, diethyl ketone, ethanol, etc. Examples of solvents with high tolerance concentrations include diethyl ketone, ethanol, etc. Here, since solvents such as methyl isopropyl ketone, methyl propyl ketone, and diethyl ketone are relatively expensive, it is possible to use ink diluted with relatively inexpensive ethanol or the like (ink with a mixed solvent of two or more components).

[0008] However, in the case of mixed solvents, if the volatilities of the two components differ, the mixing ratio after repeated viscosity adjustments may deviate from the initial mixing ratio.If an ink containing solvents with a mixing ratio that deviates from the initial mixing ratio is used in a device that is assumed to operate normally at the initial mixing ratio, there is a concern that unintended malfunctions may occur.

[0009] The present invention has been made in view of the above points, and its object is to avoid malfunctions of the device caused by changes in the component ratio of the mixed solvent, even if the viscosity of the mixed solvent ink is repeatedly adjusted within the device, in a continuous type inkjet recording device that uses high-performance ink that, for example, prevents the ink from peeling off due to adhesion of alcohol after drying. [Means for solving the problem]

[0010] To achieve the above object, a first aspect of the present disclosure can be premised on an inkjet recording device that prints on a print target using ink. The inkjet recording device includes an ink receiving unit that receives ink containing a solvent in which a ketone and an alcohol having a higher volatility than the ketone are mixed, an ink colorant, and a binder. The inkjet recording device also includes an ink flow path that sends the ink received by the ink receiving unit, and a replenisher receiving unit separate from the ink receiving unit. The replenisher receiving unit receives replenisher liquid containing a ketone and an alcohol having a higher volatility than the ketone. The inkjet recording device further includes a replenisher liquid flow path that sends the replenisher liquid received by the replenisher liquid receiving unit, a mixing container that mixes the ink sent through the ink flow path with the replenisher liquid sent through the replenisher liquid flow path to adjust the viscosity of the ink to be ejected, an adjustment ink flow path that sends ink whose viscosity has been adjusted in the mixing container, and an ejection head that ejects the ink sent through the adjustment ink flow path. The ink contains 15 mass percent or more of solids, including the ink colorant and the binder. The ketone may be one or more selected from the group consisting of diethyl ketone, methyl isopropyl ketone, and methyl propyl ketone. The mass percent concentration of the ketone in the replenisher received in the replenisher receiving section is set lower than the mass percent concentration of the ketone in the solvent of the ink received in the ink receiving section.

[0011] According to this configuration, printing is performed on a print target using ink containing 15% or more by mass of solids. This increases the ink coating thickness after drying, which tends to improve adhesion. In this case, since increasing the coating thickness reinforces adhesion, solids that do not meet the desired adhesion when the coating is thin can be used as the ink's solids. Furthermore, using solids that form a coating that is difficult to dissolve in alcohol increases alcohol resistance, suppressing ink dissolution and print peeling when, for example, disinfectant alcohol is applied. In this way, high-performance inks can be designed by using inks containing 15% or more by mass of solids.

[0012] In addition, ink costs are reduced by using ink containing a two-component mixed solvent, consisting of a ketone and a relatively inexpensive alcohol. If the viscosity of the ink in the mixing container increases over time due to solvent evaporation, a replenisher is sent to the mixing container and mixed with the ink to adjust the ink viscosity. However, because alcohol typically volatilizes more easily than ketone, the alcohol ratio is lower than the initial ratio. In contrast, in this configuration, the mass percentage concentration of ketone in the mixed replenisher is set lower than the mass percentage concentration of ketone in the ink solvent, so the alcohol ratio after adjustment in the mixing container approaches the initial ratio. This makes it less likely that the ketone-to-alcohol ratio in the mixing container will change over time. This reduces the likelihood of unintended device malfunctions. Device malfunctions, such as swelling of rubber used as a sealant or nozzle clogging due to ink precipitation, can be avoided by maintaining the ketone-to-alcohol ratio at or near the initial ratio.

[0013] An inkjet recording device according to a second aspect of the present disclosure further includes a viscometer that measures the viscosity of the ink in the mixing container, and a control unit that executes a viscosity adjustment process that controls the flow rate of the ink supplied into the mixing container via the ink receiving unit and the flow rate of the replenisher liquid supplied into the mixing container via the replenisher liquid receiving unit based on the viscosity of the ink measured by the viscometer, so that the viscosity of the ink in the mixing container is within a predetermined range.

[0014] According to this configuration, the amount of ink and replenisher liquid supplied to the mixing container can be adjusted appropriately based on the viscosity of the ink in the mixing container, thereby maintaining the viscosity of the ink within a predetermined range.

[0015] In a third aspect of the present disclosure, the control unit is configured to be able to execute a start-up process that ejects ink from the ejection head to bring it into a printable state, and executes the viscosity adjustment process after the start-up process.

[0016] According to this configuration, the viscosity of the ink in the mixing container can be adjusted to fall within a predetermined range after the start-up process, thereby maintaining good solubility of the ink colorant and binder, achieving high print quality, and preventing malfunctions in the device.

[0017] In a fourth aspect of the present disclosure, the inkjet recording apparatus further includes a recovery flow path for recovering a portion of the ink ejected from the ejection head and returning the ink to the mixing container.

[0018] That is, air is sucked into the recovery passage along with the ink, and the sucked air contains solvent components that have evaporated from the ink. At this time, the amount of alcohol, which is more volatile than ketone, evaporates relatively more, causing the ratio of ketone to alcohol to change from the initial ratio. In a configuration where such a ratio change is likely to occur, the replenisher liquid, which has a low mass percent concentration of ketone, is mixed in the mixing container, making the effects of this configuration even more pronounced.

[0019] In a fifth aspect of the present disclosure, the ink receiving unit is configured to receive an ink cartridge having a first storage medium attached thereto that stores information about the ink, and to receive the ink contained in the ink cartridge. The replenisher receiving unit is configured to receive a replenisher cartridge having a second storage medium attached thereto that stores information about the replenisher, and to receive the replenisher liquid contained in the replenisher liquid cartridge. The inkjet recording device further includes a first access unit that accesses the first storage medium, a second access unit that accesses the second storage medium, and a management unit. The management unit is configured to regulate at least one of the reception of ink via the ink receiving unit and the reception of replenisher liquid via the replenisher liquid receiving unit, based on the information about the ink obtained from the first storage medium via the first access unit and the information about the replenisher liquid obtained from the second storage medium via the second access unit.

[0020] With this configuration, it is possible to configure the printer to accept ink only from ink cartridges containing ink of a predetermined composition and not accept ink from ink cartridges containing ink of other compositions. It is also possible to configure the printer to accept replenisher liquid only from replenisher liquid cartridges containing replenisher liquid of a predetermined composition and not accept replenisher liquid from replenisher liquid cartridges containing replenisher liquid of other compositions. This makes it possible to prevent device malfunctions while achieving high print quality.

[0021] In a sixth aspect of the present disclosure, the information about the ink includes information about a ketone concentration of the ink, and the information about the replenisher includes information about a ketone concentration of the replenisher, and the management unit is configured to regulate at least one of the receipt of the ink via the ink receiving unit and the receipt of the replenisher via the replenisher receiving unit based on the information about the ketone concentration of the ink or the information about the ketone concentration of the replenisher.

[0022] This configuration allows the printer to accept only ink with a predetermined ketone concentration and not accept ink with other concentrations. Also, the printer can accept only replenisher liquid with a predetermined ketone concentration and not accept replenisher liquid with other concentrations.

[0023] In a seventh aspect of the present disclosure, the ink contains 70 to 85 mass percent or less of the solvent. The ketone concentration of the replenisher received in the replenisher receiving section can be 5 to 15 mass percentage points lower than the ketone concentration of the ink received in the ink receiving section.

[0024] In an eighth aspect of the present disclosure, the alcohol can be ethanol, i.e., industrial alcohol. The ketone concentration of the replenisher received in the replenisher receiving section can be 8 to 12 percentage points lower by mass than the ketone concentration of the ink received in the ink receiving section.

[0025] In a ninth aspect of the present disclosure, the alcohol is ethanol, and the ketone concentration of the replenisher received in the replenisher receiving section is lower in mass percentage than the ketone concentration in the ink solvent received in the ink receiving section so that the ketone concentration of the solvent component in the mixing container is maintained within ±1 point of the initial concentration even when the ink viscosity is adjusted multiple times during operation at a predetermined ambient temperature, for example, 0 to 40°C.

[0026] In other words, in conventional ink replenishing systems, repeated adjustments of ink viscosity result in changes in the ketone concentration of the solvent component in the mixing container. However, with this configuration, even if the ink viscosity is repeatedly adjusted, the ketone concentration of the solvent component in the mixing container is maintained within ±1 point of the initial concentration, thereby preventing malfunctions in the device. The predetermined ambient temperature is the temperature at which inkjet recording devices are commonly used, and can be, for example, a temperature range of 0°C to 40°C. In other words, the ketone concentration of the replenisher can be preset so that the ketone concentration does not deviate significantly from the initial concentration, no matter how many times the ink viscosity is adjusted within the temperature range of 0°C to 40°C.

[0027] In the tenth aspect of the present disclosure, the ketone concentration in the solvent of the ink received in the ink receiving section can be 70 to 80 mass percent, or can also be 72 to 78 mass percent.

[0028] In an eleventh aspect of the present disclosure, the solid content of the ink is ejected from the ejection head, adheres to the object to be printed, and dries, after which the ink has an alcohol solubility of 5% or less, so that the ink is less likely to peel off when, for example, disinfectant alcohol adheres to the ink.

[0029] A twelfth aspect of the present disclosure is a combination of the ink and the replenisher liquid used in the inkjet recording apparatus.

[0030] A thirteenth aspect of the present disclosure is the ink used in the inkjet recording device, and the ink is ink for an inkjet recording device.

[0031] A fourteenth aspect of the present disclosure is the replenisher liquid used in the inkjet recording device, and the replenisher liquid is a replenisher liquid for an inkjet recording device. [Effects of the Invention]

[0032] As described above, it is possible to obtain an ink that has high alcohol resistance after drying. Furthermore, even if the viscosity of the ink of a mixed solvent containing a ketone and an alcohol is repeatedly adjusted within an inkjet recording device, the ratio of the ketone to the alcohol can be made close to the initial ratio, so that problems in the inkjet recording device caused by changes in the ratio of the ketone to the alcohol can be avoided. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a diagram illustrating an example of the overall configuration of an inkjet printing system. [Figure 2] FIG. 2 is a block diagram illustrating a schematic configuration of the inkjet recording apparatus. [Figure 3] FIG. 3 is a diagram illustrating a schematic configuration of a discharge head. [Figure 4] FIG. 4 is a diagram illustrating an example of the paths of ink and solvent in an inkjet recording apparatus. [Figure 5] Figure 5A is a perspective view of an ink cartridge, Figure 5B is a perspective view of a refill cartridge, Figure 5C is a perspective view of the controller before the ink cartridge and refill cartridge are accommodated, Figure 5D is a perspective view of the controller holding the ink cartridge and refill cartridge and before they are fully accommodated, and Figure 5E is a perspective view of the controller with the ink cartridge and refill cartridge fully accommodated. [Figure 6] FIG. 2 is a diagram illustrating the composition of ink and replenisher liquid. [Figure 7A] FIG. 7A is a diagram showing an example of a storage format of information stored in an ink information storage unit. [Figure 7B] FIG. 7B is a diagram showing an example of a storage format of information stored in the replacement liquid information storage unit. [Figure 8] FIG. 8 is a schematic diagram of a viscometer. [Figure 9] FIG. 9 is a flowchart illustrating the basic operation of the inkjet recording apparatus. [Figure 10]FIG. 10 is a flowchart illustrating the start-up process of the inkjet recording apparatus. [Figure 11] FIG. 11 is a diagram for explaining step A in the start-up process. [Figure 12] FIG. 12 is a diagram for explaining step B in the start-up process. [Figure 13] FIG. 13 is a diagram for explaining step C in the start-up process. [Figure 14] FIG. 14 is a flowchart illustrating the shutdown process of the inkjet recording apparatus. [Figure 15] FIG. 15 is a diagram for explaining step D in the cooling treatment. [Figure 16] FIG. 16 is a diagram for explaining step E in the cooling treatment. [Figure 17] FIG. 17 is a diagram for explaining step F in the cooling treatment. [Figure 18] FIG. 18 is a flowchart illustrating the viscosity adjustment process. [Figure 19] FIG. 19 is a table showing the convergence values ​​of the ketone concentration when the ketone concentrations of the ink and the replenisher are the same. [Figure 20] FIG. 20 is a table showing the convergence values ​​of the ketone concentration when the ketone concentrations of the ink and the replenisher are different. [Figure 21] FIG. 21 is a flowchart illustrating the process executed when ink in an ink cartridge is supplied. [Figure 22] FIG. 22 is a flowchart illustrating a process executed when replenishing liquid in a replenishing liquid cartridge is supplied. [Figure 23] FIG. 23 is a table showing the relationship between the solvent ratio, the solid content, and the weight change rate of the sealing material. [Figure 24] FIG. 24 is a table showing the relationship between the solvent ratio of the ink and the replenisher liquid and the weight change rate of the solid content and the sealing material. [Figure 25] FIG. 25 is a flowchart illustrating a start-up process according to a modified example. [Figure 26]FIG. 26 is a flowchart illustrating a start-up process according to another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

[0035] In other words, although this specification describes an industrial inkjet printer as an example of an inkjet recording device, the technology disclosed herein can be applied to general equipment that uses inkjet to propel ink particles onto a workpiece, regardless of whether it is called an inkjet recording device or an industrial inkjet printer.

[0036] 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.

[0037] <Overall structure> FIG. 1 is a diagram illustrating the overall configuration of an inkjet recording system S. FIG. 2 is a diagram illustrating the schematic configuration of an inkjet recording apparatus I, and FIG. 3 is a diagram illustrating the schematic configuration of an ejection head 1 in the inkjet recording apparatus I. FIG. 4 is a diagram illustrating the paths of ink and replenisher liquid (solvent) in the inkjet recording apparatus I, where the ink can be supplied by an ink cartridge 104a and the replenisher liquid can be supplied by a replenisher liquid cartridge 105a, separately as needed. The replenisher liquid contained in the replenisher liquid cartridge 105a is the replenisher liquid for the inkjet recording apparatus. The ink contained in the ink cartridge 104a is the ink for the inkjet recording apparatus. The ink contained in the ink cartridge 104a and the replenisher liquid contained in the replenisher liquid cartridge 105a form a combination of ink and replenisher liquid. Details of the supply of ink and replenisher liquid will be described later.

[0038] The automatic printing system S illustrated in Fig. 1 is installed on a conveyor line L in a factory or the like, and is configured to print in order on each work (printing target object) W flowing along the conveyor line L. Note that the application of this disclosure is not limited to the automatic printing system S. It can also be applied to printing systems that use methods other than automatic. The conveyor line L can be configured, for example, with a belt conveyor, but is not limited to a belt conveyor.

[0039] The automatic printing system S includes an inkjet recording device I that performs printing by causing particulate ink (ink grains) to land on a workpiece W, an operation terminal 800 and an external device 900 that are connected to the inkjet recording device I, and a cleaning placement unit 200 that is connected to the inkjet recording device I and cleans the ejection head 1. The cleaning placement unit 200 is configured so that the ejection head 1 can be placed thereon when the ejection head 1 is cleaned using a cleaning liquid. Note that the cleaning placement unit 200, the operation terminal 800, and the external device 900 are not essential.

[0040] 1 to 3 includes a discharge head 1 that discharges ink droplets from a nozzle 12 and causes the ink droplets to land on a workpiece W, and a controller 100 that supplies control signals, ink, and replenisher liquid to the discharge head 1. The controller 100 supplies a control signal to the discharge head 1, thereby controlling the start and stop of ink droplet discharge and the trajectory of the discharged ink droplets.

[0041] The inkjet recording apparatus I according to this embodiment is configured as a so-called 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 the continuous system, quick-drying ink can be used without causing clogging due to ink.

[0042] To achieve ink circulation, the ejection head 1 is equipped with nozzles 12 that eject ink or replenisher liquid, as well as a gutter 16 that collects a portion of the ink or replenisher liquid ejected from the nozzles 12 (see FIG. 3). The ink or replenisher liquid collected by the gutter 16 is sent back to the controller 100 and reused. In some cases, such ink flow paths are provided with a sealant in the area that comes into contact with the ink. EPDM (ethylene propylene diene rubber) and the like are mainly used as materials for the sealant.

[0043] The operation terminal 800 has, for example, a central processing unit (CPU) and a storage device, and is connected to the controller 100. The operation terminal 800 sets the processing conditions for printing and functions as a terminal for displaying information related to printing to the user.

[0044] The processing conditions 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 processing conditions. The processing conditions include the content of the character string to be printed, etc.

[0045] 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.

[0046] The external device 900 is connected to the controller 100 as needed. 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.

[0047] Specifically, the workpiece detection sensor 901 detects the presence or absence of the workpiece W on the conveying line L, and outputs a signal (detection signal) indicating the detection result to the controller 100. The detection signal output from the workpiece detection sensor 901 functions as a trigger (print trigger) for starting printing.

[0048] The conveying speed sensor 902 is composed of, for example, a rotary encoder, and can detect the conveying speed of the workpiece W. The conveying speed sensor 902 outputs a signal (detection signal) indicating the detection result to the controller 100. The controller 100 controls the timing of ejecting ink particles from the ejection head 1 based on the detection signal input from the conveying speed sensor 902.

[0049] 2, the PLC 903 is electrically connected to the controller 100. The PLC 903 is used to control the inkjet recording system S in accordance with a predetermined sequence.

[0050] <Controller 100> The controller 100 is configured to control the ejection head 1 and to supply ink and replenisher liquid to the ejection head 1. Specifically, the controller 100 according to this embodiment includes, as control-related components, a storage unit 102 that stores processing conditions, a control unit 101 that controls the controller 100 and each unit of the ejection 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 an external source to the control unit 101.

[0051] The controller 100 includes components related to the supply of ink, etc., such as an ink supply unit 104 that supplies ink to the nozzles 12 of the ejection head 1, and a replenishment liquid supply unit 105 that supplies replenishment liquid to the nozzles 12 and the ink supply unit 104.

[0052] The control unit 101 may be configured as a separate unit from the ink supply unit 104 and replenishment liquid supply unit 105. The memory unit 102 may also be configured as a separate unit from the ink supply unit 104 and replenishment liquid supply unit 105. The operation display unit 103 may also be configured as a separate unit from the ink supply unit 104 and replenishment liquid supply unit 105. In these cases, the components can be combined to form the controller 100.

[0053] (Storage unit 102) The memory unit 102 is configured to store processing conditions set via the operation display unit 103 described below or the operation terminal 800, and to output the stored processing conditions to the control unit 101 based on a control signal from outside.

[0054] Specifically, the storage unit 102 is configured using a volatile memory, a non-volatile memory, a hard disk drive (HDD), a solid state drive (SSD), etc., and can temporarily or continuously store information indicating processing conditions. Note that, when the operation terminal 800 is incorporated into the controller 100, the operation terminal 800 may also serve as the storage unit 102.

[0055] (Control unit 101) The control unit 101 controls the ink supply unit 104 and replenishment liquid supply unit 105 in the controller 100, and the nozzles 12, charging electrodes 13, and deflection electrodes 15 in the ejection head 1, based on the processing conditions stored in the memory unit 102. The control unit 101 controls each unit, so that printing on the workpiece W is performed at a predetermined timing.

[0056] Specifically, the control unit 101 has, for example, a CPU, a memory, an input / output bus, etc., and generates a control signal based on a signal indicating information input via the operation display unit 103 or the operation terminal 800 and a signal indicating processing conditions read from the storage unit 102. The control unit 101 outputs the generated control signal to the controller 100 and each part of the inkjet recording apparatus I.

[0057] For example, when printing on the workpiece W, the control unit 101 reads the content to be printed on the workpiece W stored in the memory unit 102 and generates a control signal based on the content to be printed. Then, the control unit 101 outputs the control signal to the charging electrode 13, thereby setting the flight direction of the ink particles so as to achieve a landing position corresponding to the content to be printed.

[0058] (Operation display section 103) 1, the operation display unit 103 can be provided, for example, on a housing constituting the controller 100. This operation display unit 103 includes a display unit 103a that displays various information related to the inkjet recording apparatus I, and an operation unit 103b that includes, for example, a touch-type operation panel, buttons, switches, etc. The display unit 103a is configured, for example, as a liquid crystal display panel or an organic EL display panel, and is controlled by the control unit 101, and is configured to be able to display a user interface, etc., as will be described later.

[0059] When a user operates the operation unit 103b of the operation display unit 103, the operation information is input to the control unit 101, and the control unit 101 can detect what operation has been performed. For example, by operating the operation unit 103b, it is possible to switch the power of the inkjet recording apparatus I on / off, and to input various settings and information. Note that when the operation terminal 800 is incorporated into the controller 100, the operation terminal 800 may also serve as the operation display unit 103. The display unit 103a of the operation display unit 103 is a notification unit that notifies the user of various types of information, and the operation unit 103b is an input unit that allows various types of information to be input.

[0060] This operation and display unit 103 can also set processing conditions for printing, similar to the above-mentioned operation terminal 800. The processing conditions set by the operation and display unit 103 are output to the controller 100 and stored in its memory unit 102. In the following description, it is assumed that the user operates the operation and display unit 103, but the operation terminal 800 can also be used instead of the operation and display unit 103.

[0061] (ink supply unit 104) 4, the ink supply unit 104 has, as its main components, an ink cartridge 104a containing ink, a main tank 104b to which ink is supplied from the ink cartridge 104a, an ink distribution channel 104c, and an ink receiving unit 104d. The ink cartridge 104a, main tank 104b, and ejection head 1 are fluidly connected via the ink distribution channel 104c.

[0062] Of these, as shown in Figure 5A, ink cartridge 104a is configured to be detachable from controller 100, and by replacing it, ink can be replenished into main tank 104b. When attaching ink cartridge 104a to controller 100, first, as shown in Figure 5C, ink receiving portion 104d is positioned so that it faces outward from controller 100, then ink cartridge 104a is held in ink receiving portion 104d as shown in Figure 5D, and finally, ink receiving portion 104d is rotated so that ink cartridge 104a is housed within controller 100 as shown in Figure 5E.

[0063] As shown in FIG. 6, the ink contained in the ink cartridge 104a contains an ink colorant, a binder, and a solvent. The solvent is a mixed solvent of two or more components, a mixture of a ketone and an alcohol having a higher volatility than the ketone. The ketone is a ketone for dissolving ink, and is one or more selected from a group including diethyl ketone, methyl isopropyl ketone, and methyl propyl ketone. In this embodiment, the alcohol is industrial alcohol (denatured ethanol), to which 1-propanol or isopropyl alcohol is added as a denaturant. Other denaturants include, for example, methanol and methyl ethyl ketone, and any of these denaturants may be added. Furthermore, alcohols other than ethanol may be used as long as they have a higher volatility than the ketone, or ethanol may be mixed with an alcohol having a higher volatility than the ketone. A high-performance ink with high alcohol resistance and strong adhesion may contain a mixed solvent, for example, a mixture of diethyl ketone, which has a relatively high tolerance concentration among C5 ketones, and denatured ethanol, which is relatively readily available.

[0064] The ink in the ink cartridge 104a contains 70 to 85 mass percent of solvent. The lower limit of the solvent content can be 70 mass percent or more, or 75 mass percent or more. The upper limit of the solvent content can be 85 mass percent or less, or 80 mass percent or less. If the lower limit of the solvent content is less than 70 mass percent, the ink contains a large amount of solids, including ink colorants and binders, and the solids cannot be completely dissolved in the solvent. If the solubility of the solids deteriorates, the solids will precipitate more due to temperature changes, which can cause problems such as poor print stability and increased clogging of the filter F described below. Furthermore, when the solvent evaporates, the ink's viscosity increases, potentially quickly reaching a viscosity range that makes it difficult to suction with the pump described below. Therefore, the lower limit of the solvent content in the ink in the ink cartridge 104a is set to 70 mass percent or more.

[0065] Furthermore, if the upper limit of the solvent content in the ink in ink cartridge 104a were set higher than 85 mass percent, the solids content would decrease, making it difficult to design a high-performance ink with the desired adhesive properties. Furthermore, if the upper limit of the solvent content in the ink in ink cartridge 104a were set higher than 85 mass percent, the solids content would decrease, and even if the ketone concentration in the ink solvent were constant, the ketone concentration in the ink would increase, which would increase the amount of swelling of the sealing material (EPDM) used in inkjet recording apparatus I, and could potentially have a negative impact on the life of the sealing material. For this reason, the upper limit of the solvent content in the ink in ink cartridge 104a is set to 85 mass percent or less.

[0066] Since the higher the vapor pressure, the higher the volatility, and the lower the vapor pressure, the lower the volatility, an alcohol with higher volatility than a ketone can also be said to have a higher vapor pressure than a ketone. More specifically, the higher the vapor pressure in the temperature range assumed in the inkjet recording apparatus I, the higher the volatility, and the lower the vapor pressure in this temperature range, the lower the volatility. The assumed temperature range here is, for example, approximately 0°C to 50°C. Furthermore, in many cases, the lower the boiling point, the higher the volatility, and the higher the boiling point, the lower the volatility, so an alcohol with higher volatility than a ketone can also be said to have a lower boiling point than a ketone.

[0067] Among the solvents of the ink in ink cartridge 104a, if ketone is the main solvent (solvent A) and alcohol is the secondary solvent (solvent B), the combination of solvents may be such that the vapor pressure of solvent A / vapor pressure of solvent B at 10°C is different from the vapor pressure of solvent A / vapor pressure of solvent B at 50°C.

[0068] The ink in the ink cartridge 104a contains 15% by mass or more of solids, including ink colorants and binders. The lower limit of the solids content in the ink can be 20% by mass or more. The upper limit of the solids content in the ink can be 30% by mass or less, or 25% by mass or less. By containing 15% by mass or more of solids in the ink, even if, for example, disinfectant alcohol adheres to the printing surface (the surface where the ink has solidified) after the ink has adhered to the workpiece W and dried, dissolution of the ink and peeling of the print are suppressed.

[0069] The alcohol resistance of such a printed surface can be determined by the alcohol solubility of the ink after drying. The solid content of the ink is set so that the alcohol solubility after it is ejected from the ejection head 1, adheres to the workpiece W, and dries is 5% or less. The alcohol solubility of the ink after drying may be, for example, 4% or less. Alcohol solubility is the amount of alcohol that diffuses into the solution when a 100g object is immersed in 99.9% pure anhydrous ethanol. For example, an alcohol solubility of 5% means that when a 100g object is immersed in 99.9% pure anhydrous ethanol, the weight of the solid content becomes 95g.

[0070] The ink colorant may be a dye-based colorant or a pigment-based colorant. Dye-based ink colorants are present in the ink in a dissolved state in the solvent. On the other hand, pigment-based ink colorants are present in the ink in a dispersed state without being dissolved in the solvent.

[0071] The color of the ink colorant may be, for example, black, but is not limited to black and may be a yellow or white pigment-based colorant. The binder is a so-called adhesive that fixes the ink colorant to the printing surface of the workpiece W. The binder exists in the ink in a state dissolved in a solvent, and after adhering to the printing surface of the workpiece W, the ink is fixed to the printing surface as the solvent evaporates. In this embodiment, a binder whose alcohol solubility after drying falls within the above range can be used.

[0072] As also shown in Figure 5C, ink receiving section 104d is provided in controller 100 and is configured to be able to receive ink cartridge 104a. Ink receiving section 104d is configured, for example, to be able to receive ink cartridge 104a from outside, and also to be able to remove the received ink cartridge 104a. Receiver 104a from outside can be called "receiving ink cartridge 104a."

[0073] The ink receiving unit 104d is configured to not only receive the ink cartridge 104a, but also receive the ink contained in the ink cartridge 104a. Specifically, the ink receiving unit 104d has a suction tube or the like that communicates with the inside of the ink cartridge 104a, and is configured to be able to suck the ink contained in the ink cartridge 104a through the suction tube or the like. Sucking the ink contained in the ink cartridge 104a can be called "receiving ink." Receiving the ink cartridge 104a and receiving the ink are separate processes, and although details will be described later, there are cases where the ink receiving unit 104d receives the ink cartridge 104a but does not receive the ink. Note that the ink receiving unit 104d is configured to be unable to receive ink unless it receives the ink cartridge 104a.

[0074] As shown in FIG. 4, the ink supply unit 104 further includes an ink installation detection switch 104f for detecting whether the ink cartridge 104a is installed. The ink installation detection switch 104f can be provided in the ink receiving unit 104d and is configured, for example, by a microswitch or proximity switch. The ink installation detection switch 104f is disposed so that it turns ON only when the ink cartridge 104a is installed in the correct position in the ink receiving unit 104d, and is OFF in all other cases. The ink installation detection switch 104f is connected to the control unit 101, and the detection result of the ink installation detection switch 104f is output to the control unit 101.

[0075] As shown in FIG. 5A, ink cartridge 104a is equipped with ink information storage unit (first storage medium) 104e. Ink information storage unit 104e is composed of a nonvolatile memory or the like that stores information about the ink. The information about the ink includes information about the type, manufacturing date, and ketone concentration. Information is stored in ink information storage unit 104e in a format such as that shown in FIG. 7A, for example. That is, there are multiple addresses, and each address is associated with an information type and data as an item. Information types are categorized into items such as "ink / replenisher," "manufacturing date," and "ketone concentration." "Ink / replenisher" indicates whether the liquid contained in ink cartridge 104a is ink or replenisher. As will be described later, this information distinguishes ink cartridge 104a from replenisher cartridge 105a. In the case of ink information storage unit 104e, since ink cartridge 104a is equipped with ink cartridge 104a, the data is "ink."

[0076] Additionally, the "date of manufacture" is an item that specifies the date on which the ink contained in the ink cartridge 104a was manufactured or the date on which the ink cartridge 104a was manufactured. Because the date on which the ink was manufactured and the date on which the ink cartridge 104a was filled with ink are approximately the same, the "date of manufacture" can also be said to be the date on which the ink cartridge 104a was filled with ink. The reason the date of manufacture is stored in the ink information storage unit 104e is that after manufacture (or after filling into the ink cartridge 104a), the solvent contained in the ink inevitably evaporates, albeit in trace amounts, to the outside of the ink cartridge 104a. Therefore, it is estimated that the earlier the date of manufacture, the more the solvent component of the ink in the ink cartridge 104a has decreased. As will be described in more detail below, the date of manufacture is used when suctioning ink as information for estimating the concentration of the solvent component of the ink in the ink cartridge 104a.

[0077] Additionally, the "ketone concentration" stored in the ink information storage unit 104e indicates the ketone concentration in the solvent of the ink contained in the ink cartridge 104a. The ketone concentration is the ketone concentration obtained by analyzing the ink immediately before filling the ink cartridge 104a using a nuclear magnetic resonance (NMR) spectrometer or the like, and this numerical value can be stored as data in the ink information storage unit 104e. Ink is manufactured to have a constant ketone concentration, but the mixed amount of alcohol and ketone can vary slightly, so the ketone concentration is not necessarily the same for all ink cartridges 104a. Therefore, by measuring the ketone concentration in the solvent of the ink in the ink cartridge 104a and storing it in the ink information storage unit 104e, this information can be used to estimate the concentration of the solvent component of the ink in the ink cartridge 104a when suctioning the ink, as described below. As shown in Figure 6, the ketone concentration in the ink solvent is the mass percentage concentration of the ketone Kin contained in the solvent SV when focusing on the solvent SV in the ink In, and is not the concentration for the entire ink In.

[0078] The ink supply unit 104 further includes an ink information access unit (first access unit) 104g that accesses the ink information storage unit 104e. The ink information access unit 104g can be configured with a reader or the like that can read the information stored in the ink information storage unit 104e. The ink information access unit 104g is connected to the control unit 101, and the information about the ink read by the ink information access unit 104g is output to the control unit 101.

[0079] In this way, the inkjet recording apparatus I according to this embodiment is configured as a so-called "cartridge-type" inkjet printer, but is not limited to this configuration. For example, it may be configured to have a tank that can be opened and closed manually, and to replenish the tank with ink.

[0080] The main tank 104b is a container that stores ink to be supplied to the nozzles 12, and more specifically, is a mixing container that mixes ink with replenisher liquid to adjust the viscosity of the ink to a desired value when it is ejected. In other words, ink whose viscosity has been adjusted by replenisher liquid is stored in the main tank 104b.

[0081] The ink circulation path 104c is a path that includes an ink ejection path that supplies the ink in the main tank 104b after viscosity adjustment to the ejection head 1, and a recovery path that returns the ink sucked by the gutter 16 to the main tank 104b, and constitutes an adjusted ink flow path. The ink circulation path 104c allows ink to circulate between the ejection head 1 and the controller 100.

[0082] As will be described later, the ink flow path 104c is provided with a plurality of solenoid valves, including a first valve V1, and a plurality of pumps, including an ink pump P1. Of these, each solenoid valve opens and closes in response to a control signal output from the control unit 101, thereby controlling the flow of ink. Meanwhile, each pump receives a control signal output from the control unit 101 to pump ink, and can control the flow of ink in the same way as the solenoid valves.

[0083] (Replenisher supply section 105) The replenisher supply unit 105 has, as its main components, a replenisher cartridge 105a containing replenisher liquid, a conditioning tank 105b, a replenisher liquid flow path 105c, and a replenisher liquid receiving unit 105d. The replenisher cartridge 105a, the conditioning tank 105b, and the ejection head 1 are fluidly connected via the replenisher liquid flow path 105c. The replenisher liquid flow path 105c, through which the replenisher liquid flows, is made up of multiple paths, some of which also serve as paths for returning ink from the gutter 16.

[0084] 5B, the refill liquid cartridge 105a is configured to be detachable from the controller 100. By replacing this refill liquid cartridge 105a, it is possible to replenish the controller 100 with refill liquid. The method for attaching the refill liquid cartridge 105a to the controller 100 is the same as the method for attaching the ink cartridge 104a to the controller 100.

[0085] The replenisher liquid of this embodiment is a solvent. Specifically, as shown in FIG. 6, it is a mixed solvent of two or more components, a mixture of a ketone and an alcohol with higher volatility than the ketone. The ketone is a replenisher ketone, and, like the ketone used to dissolve the ink contained in the ink cartridge 104a, it is composed of one or more selected from a group including diethyl ketone, methyl isopropyl ketone, and methyl propyl ketone. The alcohol contained in the replenisher liquid is the same as the alcohol contained in the ink contained in the ink cartridge 104a. The alcohol contained in the replenisher liquid may be an alcohol other than ethanol as long as it has a higher volatility than the ketone, or a mixture of ethanol and an alcohol with a higher volatility than the ketone may be used. A replenisher liquid suitable for high-performance inks with high alcohol resistance and strong adhesion may contain a mixed solvent, for example, a mixture of diethyl ketone, which has a relatively high tolerance concentration among C5 ketones, and denatured ethanol, which is relatively easy to obtain.

[0086] The mass percentage concentration of the ketone in the replenisher liquid is set lower than the mass percentage concentration of the ketone in the solvent of the ink contained in the ink cartridge 104a. Specifically, the mass percentage concentration of the ketone in the replenisher liquid is set lower by 5 to 15 points than the mass percentage concentration of the ketone in the solvent of the ink contained in the ink cartridge 104a. The mass percentage concentration of the ketone in the replenisher liquid may also be set lower by 8 to 12 points than the mass percentage concentration of the ketone in the solvent of the ink contained in the ink cartridge 104a. The reasons for setting the ketone concentration in the replenisher liquid lower than the ketone concentration in the ink and the resulting effects will be described later.

[0087] Replenisher cartridge 105a containing replenisher liquid may be provided in combination with ink cartridge 104a containing ink with a corresponding ketone concentration, or may be provided alone for use with ink with a corresponding ketone concentration. For example, replenisher liquid may be provided in such a way that the ink to be used with the replenisher liquid is specified by the ink type or ketone concentration.

[0088] The ink cartridge 104a containing the ink may be provided in combination with a replenisher cartridge 105a containing a replenisher having a corresponding ketone concentration, or may be provided alone to be used with a replenisher having a corresponding ketone concentration. For example, the ink may be provided in such a way that the replenisher to be used with the ink is specified by the replenisher type or ketone concentration.

[0089] As shown in Figures 5A and 5B, the ink cartridge 104a and the replenisher cartridge 105a may have substantially the same shape. Alternatively, the ink cartridge 104a may be provided with an ink information storage unit (first storage medium) 104e attached thereto, and the replenisher cartridge 105a may be provided with a replenisher information storage unit (second storage medium) 105e attached thereto. In this case, the ink information storage unit (first storage medium) 104e and the replenisher information storage unit (second storage medium) 105e each store information about their respective contents in a format readable by a common inkjet recording apparatus I. The information about the contents may include, for example, the type of the contents, such as ink or replenisher, the remaining amount of the contents, the manufacturing date, and the ketone concentration.

[0090] 5C, the ink receiving portion 104d and the replenishment liquid receiving portion 105d in the inkjet recording apparatus I may have substantially the same shape, and in this case, the ink cartridge 104a and the replenishment liquid cartridge 105a may have substantially the same shape at least in the portion that comes into contact with the ink receiving portion 104d or the replenishment liquid receiving portion 105d in the inkjet recording apparatus I. For example, the ink cartridge 104a and the replenishment liquid cartridge 105a may have different shapes to the extent that they are prevented from being inserted incorrectly, and the remaining portions that come into contact with the ink receiving portion 104d or the replenishment liquid receiving portion 105d may have the same shape.

[0091] The replenishment liquid receiving section 105d is provided in the controller 100 separately from the ink receiving section 104d, and is configured to be able to receive the replenishment liquid cartridge 105a. The replenishment liquid receiving section 105d is configured, for example, in the same manner as the ink receiving section 104d. Storing the replenishment liquid cartridge 105a from outside can be called "receiving the replenishment liquid cartridge 105a."

[0092] The replenisher liquid receiving section 105d is configured to not only receive the replenisher liquid cartridge 105a, but also receive the replenisher liquid contained in the replenisher liquid cartridge 105a. Specifically, the replenisher liquid receiving section 105d has a suction tube or the like that communicates with the inside of the replenisher liquid cartridge 105a, and is configured to be able to suck the ink contained in the replenisher liquid cartridge 105a through the suction tube or the like. Sucking the replenisher liquid contained in the replenisher liquid cartridge 105a can be called "receiving replenisher liquid." Receiving the replenisher liquid cartridge 105a and receiving replenisher liquid are separate operations, and although details will be described later, there may be cases where the replenisher liquid receiving section 105d receives the replenisher liquid cartridge 105a but does not receive the replenisher liquid. Note that the replenisher liquid receiving section 105d is configured to be unable to receive replenisher liquid unless it receives the replenisher liquid cartridge 105a.

[0093] The replenisher supply unit 105 further includes a replenisher installation detection switch 105f for detecting whether the replenisher cartridge 105a is installed. The replenisher installation detection switch 105f can be provided in the replenisher receiving unit 105d, and like the ink installation detection switch 104f, is arranged so that the replenisher installation detection switch 105f is turned ON only when the replenisher cartridge 105a is installed in the correct position in the replenisher receiving unit 105d, and is turned OFF in all other cases. The replenisher installation detection switch 105f is connected to the control unit 101, and the detection result of the replenisher installation detection switch 105f is output to the control unit 101.

[0094] A replenisher information storage unit (second storage medium) 105e is attached to the replenisher cartridge 105a. The replenisher information storage unit 105e is composed of a non-volatile memory or the like that stores information about the replenisher. The information about the replenisher, like the information about the ink, includes information about the type, manufacturing date, and ketone concentration, and the replenisher information storage unit 105e stores the information in a format such as that shown in FIG. 7B. In the case of the replenisher information storage unit 105e, the data for the "ink / replenisher" item is "replenisher" because the replenisher information storage unit 105e is attached to the replenisher cartridge 105a.

[0095] Furthermore, the "date of manufacture" is an item that specifies the date on which the replenisher liquid contained in the replenisher liquid cartridge 105a was manufactured or the date on which the replenisher liquid cartridge 105a was manufactured. Since the date on which the replenisher liquid was manufactured and the date on which the replenisher liquid cartridge 105a was filled are almost the same, the "date of manufacture" can also be said to be the date on which the replenisher liquid cartridge 105a was filled. The reason for storing the date of manufacture in the replenisher liquid information storage unit 105e is the same as in the case of ink, and the date of manufacture is used when suctioning the replenisher liquid as information for estimating the concentration of the solvent component of the replenisher liquid in the replenisher liquid cartridge 105a.

[0096] The "ketone concentration" stored in the replenisher information storage unit 105e indicates the ketone concentration of the replenisher liquid contained in the replenisher liquid cartridge 105a. As with ink, the ketone concentration is measured before refilling, and the numerical value can be stored as data in the replenisher liquid information storage unit 105e. While replenisher liquid is manufactured to have a consistent ketone concentration, the amount of alcohol and ketone mixed may vary slightly, and the ketone concentration is not necessarily the same in all replenisher liquid cartridges 105a. Therefore, measuring and storing the ketone concentration of the replenisher liquid in the replenisher liquid cartridge 105a can be used as information to estimate the ketone concentration of the replenisher liquid in the replenisher liquid cartridge 105a when drawing the replenisher liquid, as described below. As shown in FIG. 6, the ketone concentration in the replenisher liquid refers to the mass percent concentration of the ketone Kre contained in the solvent in the replenisher liquid Re. However, since the replenisher liquid Re is composed almost entirely of solvent, the ketone concentration may also refer to the mass percent concentration of the ketone Kre in the entire replenisher liquid Re.

[0097] The replenishment liquid supply unit 105 further includes a replenishment liquid information access unit (second access unit) 105g that accesses the replenishment liquid information storage unit 105e. The replenishment liquid information access unit 105g can be configured with a reader or the like that can read the information stored in the replenishment liquid information storage unit 105e. The replenishment liquid information access unit 105g is connected to the control unit 101, and the information about the replenishment liquid read by the replenishment liquid information access unit 105g is output to the control unit 101.

[0098] A replenisher tank may be provided instead of the replenisher cartridge 105a. The replenisher supply unit 105 has a function of detecting whether the replenisher liquid in the replenisher cartridge 105a has run out or whether there is little replenisher liquid remaining. The replenisher liquid contained in the replenisher cartridge 105a is used to adjust the ink concentration and is also used as a cleaning agent to clean the paths through which the ink flows.

[0099] The conditioning tank 105b is configured to store the replenishment liquid used for cleaning. The replenishment liquid used for cleaning contains ink. As described above, the replenishment liquid ejected from the nozzles 12 is collected by the gutter 16 in the same manner as the ink.

[0100] The replenisher liquid flow path 105c is a path for supplying the replenisher liquid to the ejection head 1, the main tank 104b, etc., and for returning the replenisher liquid sucked by the gutter 16 to the main tank 104b.

[0101] As will be described later, the replenishment liquid flow path 105c is provided with a plurality of solenoid valves including a sixteenth valve V16 and a plurality of pumps including a replenishment liquid pump P2. Of these, each solenoid valve opens and closes in response to a control signal output from the control unit 101, thereby controlling the flow of the replenishment liquid. Meanwhile, each pump receives a control signal output from the control unit 101 to pump the replenishment liquid, thereby controlling the flow of the replenishment liquid in the same manner as the solenoid valves.

[0102] The classification of the replenishment liquid flow path 105c and the ink flow path 104c described above is merely a convenient classification made for the sake of simplicity of explanation. The replenishment liquid flow path 105c and the ink flow path 104c are essentially inseparable because they are connected to each other or one serves as the other.

[0103] (Power supply section 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.

[0104] (Other components) The controller 100 is provided with a connection cable 107, which is a bundle of covered electrical wiring for sending and receiving control signals, tubes for sending and receiving ink (specifically, tubes defining the ink flow path 104c), and tubes for sending and receiving replenisher liquid (specifically, tubes defining the replenisher liquid flow path 105c). This connection cable 107 is flexible, and is connected to the upper end of the ejection head 1 (see FIG. 1). The controller 100 and the ejection head 1 are electrically and fluidically connected via this connection cable 107.

[0105] <Discharge head 1> The ejection head 1 ejects ink as particulate ink droplets, the viscosity of which has been adjusted based on the control signal, ink, and replenisher liquid supplied from the controller 100. The ejection head 1 deflects the flight direction of the ejected ink droplets and causes the deflected ink droplets to land on the surface of the workpiece W, thereby printing on the workpiece W.

[0106] Specifically, as shown in Figure 3, the ejection head 1 of this embodiment includes a vibrator 11 that generates ink particles by vibrating the ink, a nozzle 12 that ejects the ink vibrated by the vibrator 11, a charging electrode 13 that charges the ink particles ejected from the nozzle 12, a charge detection sensor 14 that monitors the charged state of the ink, a deflection electrode 15 that deflects the flight direction of the ink charged by the charging electrode 13, and a gutter 16 that collects the ink that has been undeflected by the deflection electrode 15 or replenisher liquid ejected from the nozzle 12.

[0107] The ejection head 1 includes a housing 10 that houses a vibrator 11, a nozzle 12, a charging electrode 13, a charge detection sensor 14, a deflection electrode 15, and a gutter 16, and defines a flight space S1 for ink droplets. An opening A is formed on the bottom surface of the housing 10 of the ejection head 1, for ejecting ink deflected by the deflection electrode 15 to the outside. The ink is ejected from this opening A downward into the housing 10.

[0108] 1, during printing, the discharge head 1 is supported by, for example, a support member 2. When the discharge head 1 is supported by the support member 2, the discharge head 1 is positioned so that its discharge holes A face the printing surface of the workpiece W from above.

[0109] Below, each part of the ejection head 1 will be explained in order. In the following description, the "upper-lower direction" refers to the direction along the vertical direction. For example, the upper side of the paper in FIG. 3 corresponds to the "upper direction," and the lower side of the paper in the same figure corresponds to the "lower direction." In other figures, the corresponding direction is also called the "upper-lower direction."

[0110] (Vibrator 11) As shown in FIG. 3, the vibrator 11 is provided in the nozzle 12. The vibrator 11 according to this embodiment has a built-in device (for example, a piezoelectric element) for applying up and down vibrations to the ink. This vibrator 11 is configured so that ink is supplied via a connection cable 107, and is able to vibrate the ink thus supplied. The ink vibrated by the vibrator 11 is supplied to the nozzle 12. Although not shown in the figure, the vibrator 11 according to this embodiment is grounded.

[0111] (Nozzle 12) As shown in FIG. 3, the main body of the nozzle 12 is connected to the lower end of the vibrator 11. A discharge port (not shown) is formed on the lower end surface of the nozzle 12 so as to open downward, and discharges ink that has been vibrated by the vibrator 11. A suction path 27 (shown in FIG. 4, etc.) constituting the ink supply unit 104 is connected to the flow path within the nozzle 12, and negative pressure can be applied to the flow path within the nozzle 12. The flow path within the nozzle 12 is used to suck ink from within the nozzle 12. The suction path 27 also functions as a return path for releasing pressure inside the ejection head 1, for example, during a shutdown. Replenisher liquid can also be sucked from the nozzle 12 through the suction path 27.

[0112] Ink ejected from the nozzle 12 without being vibrated by the vibrator 11 flows as a shaft-shaped so-called "ink shaft." On the other hand, vibrated ink is atomized immediately after being ejected from the nozzle 12, becoming so-called "ink droplets." The ink ejected from the nozzle 12 is shaft-shaped immediately after being ejected from the nozzle 12, but becomes particle-shaped as it moves away from the nozzle 12. The position where it becomes particle-shaped is called the breakpoint. The ink ejected from the nozzle 12 (ink droplets) passes through the charging electrode 13, which will be described later.

[0113] The replenisher liquid supplied to clean the discharge head 1 passes through the vibrator 11 and the nozzle 12 in this order, and is then discharged from the tip of the nozzle 12. The discharged replenisher liquid flows axially and passes through the charged electrode 13.

[0114] (Charged electrode 13) 3, the charging electrode 13 is made up of a pair of conductive metal plates and is disposed below the nozzle 12. The pair of metal plates that make up the charging electrode 13 are fixed to the housing 10 in such a manner that their respective longitudinal directions are aligned in the up-down direction and that they face each other horizontally. Ink ejected from the nozzle 12 passes between the pair of metal plates.

[0115] A potential (positive potential) is applied to the charging electrode 13 according to this embodiment at least when a printing operation is performed. This generates a potential difference between the vibrator 11 and the charging electrode 13, making it possible to charge ink droplets passing through the charging electrode 13. In order to charge each ink droplet, the charging electrode 13 according to this embodiment is disposed near a breakpoint where the ink ejected from the nozzle 12 breaks into particles.

[0116] 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 charge amount (magnitude of negative charge) of each ink droplet becomes larger compared to when a lower voltage is applied. When an ink droplet has a large charge amount, it is deflected more by the deflection electrode 15 compared to when the charge amount is small. The controller 100 can control the deflection amount of the ink droplet by adjusting the magnitude of the pulse potential. The ink droplet charged by the charging electrode 13 reaches the deflection electrode 15 after passing by the side of the charge detection sensor 14. Furthermore, the replenisher liquid ejected from the nozzle 12 reaches the deflection electrode 15 without being charged.

[0117] (Charge detection sensor 14) As shown in Fig. 3, the charge detection sensor 14 is disposed below the charging electrode 13. More specifically, the charge detection sensor 14 is disposed below the metal plate that constitutes the charging electrode 13 (the metal plate on the right side of the paper in the example shown in Fig. 3) so as not to intersect with the trajectory of the flying ink particles. By disposing the charge detection sensor 14 in this manner, it is possible to avoid collisions between the ink particles and the charge detection sensor 14.

[0118] The charge detection sensor 14 according to this embodiment is connected to a circuit board provided inside the housing 10. The charge detection sensor 14 can detect the charge state of ink particles passing by its side. The detection result by the charge detection sensor 14 is output to the control unit 101 as a detection signal. Based on this detection signal, the control unit 101 can determine whether each ink particle is appropriately charged.

[0119] (Deflection electrode 15) 3, the deflection electrode 15 is composed of a pair of conductive metal plates (so-called "counter electrodes") and is arranged 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.

[0120] A voltage that can be controlled by the controller 100 is applied to the deflection electrode 15. This generates a potential difference between the pair of metal plates that make up the deflection electrode 15. This potential difference can deflect the flight direction of the ink droplets according to the amount of charge on the ink droplets. The flight direction of the ink droplets can be deflected along the alignment direction of the pair of metal plates that make up the deflection electrode 15.

[0121] That is, the flight direction of the ink particles can be controlled via the voltages applied to the charging electrode 13 and the deflecting electrode 15, respectively. The ink particles whose flight direction is controlled in this way include those deflected by the deflecting electrode 15 and those not deflected by the deflecting electrode 15 (non-deflected). Of these, the ink particles deflected by the deflecting electrode 15 are involved in printing on the workpiece W. The ink particles deflected by the deflecting electrode 15 are ejected from an opening A provided on the bottom surface of the casing 10 and land on the workpiece W.

[0122] On the other hand, ink particles that are not deflected by the deflection electrode 15 do not participate in printing on the workpiece W. These ink particles, or axial ink that has not been atomized in the first place, reach the gutter 16, as shown by the dashed line in Figure 3. Similarly, replenishment liquid that has been used to clean the nozzles 12, etc. of the ejection head 1 and has passed through the deflection electrode 15 also reaches the gutter 16.

[0123] (Gutter 16) 3, the gutter 16 is configured as a curved pipe with its open end facing upward, and is disposed below the deflection electrode 15. The gutter 16 according to this embodiment can collect ink that is not involved in printing on the workpiece W and the replenisher liquid that has passed through the nozzle 12 (specifically, the replenisher liquid that has been ejected from the nozzle 12).

[0124] In this embodiment, the open end (upstream end) of the gutter 16 and the open end of the nozzle 12 are arranged to face each other, and the open end of the nozzle 12 is located directly above the open end of the gutter 16. This arrangement makes it possible for the fluid that flows vertically from the open end of the nozzle 12 to be received from the open end of the gutter 16. The ink or replenisher liquid collected by the gutter 16 is returned to the main tank 104b of the controller 100 via a recovery flow path.

[0125] The collection of ink or replenisher liquid by the gutter 16 will be described below with reference to Fig. 4. Note that the component marked with the symbol F in Fig. 4 is an example of a filter. In the following description, a description of the arrangement, configuration, etc. of the filter F will be omitted.

[0126] <Ink and refill fluid paths> The ink distribution path 104c has, as paths related to the supply of ink to the nozzles 12, a first ink path 21 connecting the ink cartridge 104a and the first branch portion 51, a sixth ink path 26 connecting the first branch portion 51 (more specifically, a portion midway in the second ink path 22) and the second branch portion 52, an eighth ink path 28 connecting the second branch portion 52 and the main tank 104b, and a fourth ink path 24 connecting the main tank 104b and the nozzles 12. Here, the sixth ink path 26 according to this embodiment is connected to the second branch portion 52 via a fifth ink path 25, which will be described later.

[0127] The ink received by the ink receiving portion 104d is sent to the main tank 104b via the first ink path 21, the first branch portion 51, the second ink path 22, the sixth ink path 26, the second branch portion 52, and the eighth ink path 28. In other words, the ink flow path that sends the ink received by the ink receiving portion 104d is made up of the first ink path 21, the first branch portion 51, the second ink path 22, the sixth ink path 26, the second branch portion 52, and the eighth ink path 28.

[0128] The ink supply unit 104 also includes a viscometer 53. The viscosity of ink varies depending on the concentration of the solvent in the ink. In other words, the viscosity of ink varies depending on the ratio of solids to solvent, and the higher the ratio of solids, the higher the ink viscosity. By utilizing this, the concentration of the solvent in the ink can be estimated by measuring the viscosity of the ink. As shown schematically in FIG. 8, the viscometer 53 includes an upper container 53a and a lower container 53b. A predetermined amount of ink is introduced into the upper container 53a. A drip hole 53c is provided at the bottom of the upper container 53a for dripping the ink inside. The lower container 53b is positioned to receive the ink dripped from the drip hole 53c. The ink in the lower container 53b is returned to the main tank 104b. The viscosity of the ink can be calculated based on the time it takes for the ink in the upper container 53a to change from level H to level L, and the concentration of the solvent in the ink can also be estimated.

[0129] The ink flow path 104c has, as a path related to viscosity measurement by the viscometer 53, a second ink path 22 that connects the first branch portion 51 and the main tank 104b and has the viscometer 53 interposed therein, and a third ink path 23 that is provided independently of the second ink path 22 and connects the main tank 104b and the first branch portion 51.

[0130] Furthermore, the ink flow path 104c has a fifth ink path 25 that connects the gutter 16 and the main tank 104b as a path related to the collection of ink by the gutter 16. When ink particles are collected in the gutter 16, the fifth ink path 25 forms a collection flow path that guides the collected ink particles to the ink supply unit 104. When replenisher liquid is sucked into the gutter 16, the replenisher liquid is collected by the fifth ink path 25.

[0131] Here, a circulation pump P4, an eleventh valve V11, and a viscometer 53 are provided in this order in the second ink path 22. The circulation pump P4 is a pump that applies negative pressure to the suction path 27. Since the suction path 27 is connected to the flow path in the nozzle 12, when the circulation pump P4 is operated, the ink in the nozzle 12 can be sucked through the suction path 27.

[0132] The fourth ink path 24 is provided with, in this order, an ink pump P1, a pressure reducing valve, a pressure gauge, and a fourteenth valve V14. The fifth ink path 25 is provided with, in this order, a tenth valve V10, a gutter pump P3, and a second branch section 52. The gutter pump P3 is a suction pump that creates a negative pressure in the fifth ink path 25, thereby sucking ink particles when ink particles are collected in the gutter 16, and sucking replenishment liquid when replenishment liquid is collected in the gutter 16.

[0133] On the other hand, the replenishment liquid flow path 105c has a first replenishment liquid path 31 connecting the replenishment liquid cartridge 105a and the nozzle 12 as a path related to the supply of replenishment liquid to the nozzle 12.

[0134] Furthermore, the replenishment liquid flow path 105c, which is a path related to adjusting the viscosity of the ink with the replenishment liquid contained in the replenishment liquid cartridge 105a, has a second replenishment liquid path 32 that connects a midpoint in the first replenishment liquid path 31 and the first branch portion 51. The second replenishment liquid path 32 is a part that constitutes a replenishment liquid flow path that sends the replenishment liquid received in the replenishment liquid receiving portion 105d.

[0135] The replenisher liquid flow path 105c also has a third replenisher liquid flow path 33 that connects the first branch portion 51 and the conditioning tank 105b. The fifth ink flow path 25, exemplified as the ink flow path 104c, is related to the collection of replenisher liquid by the gutter 16. As mentioned above, the classification of "ink flow path 104c" and "replenisher liquid flow path 105c" is merely a convenient classification.

[0136] The first replenishment liquid path 31 is provided with, in this order, an optical empty detection mechanism 44, a replenishment liquid pump P2, a sixteenth valve V16, and a twelfth valve V12. A cleaning nozzle 19 serving as a replenishment liquid sprayer is connected to the first replenishment liquid path 31. The cleaning nozzle 19 is a nozzle for spraying replenishment liquid onto the vibrator 11, the exterior of the nozzle 12 (around the outlet 12a), the charging electrode 13, the deflection electrode 15, etc., of the discharge head 1, thereby cleaning them, and is capable of spraying replenishment liquid as a cleaning liquid. A fifteenth valve V15 is provided midway from the cleaning nozzle 19 to the first replenishment liquid path 31.

[0137] Here, the first branch section 51 has a fifth valve V5 that opens and closes between the third ink path 23 and the second ink path 22, an eighth valve V8 that opens and closes between the first ink path 21 and the second ink path 22, a ninth valve V9 that opens and closes between the third replenishment liquid path 33 and the second ink path 22, and a thirteenth valve V13 that opens and closes between the second replenishment liquid path 32 and the second ink path.

[0138] The second branch section 52 also has a first valve V1 that opens and closes between the sixth ink path 26 and the eighth ink path 28, a third valve V3 that opens and closes between the sixth ink path 26 and the conditioning tank 105b, and a fourth valve V4 that opens and closes between the sixth ink path 26 and the waste liquid tank (shown as "waste liquid" in Figure 4).

[0139] The control unit 101 can configure a desired flow path within the controller 100 by outputting control signals to valves provided in each path, such as the eleventh valve V11, and outputting control signals to each valve forming the first branch section 51 and the second branch section 52.

[0140] For example, by opening the eighth valve V8 and the first valve V1, it becomes possible to refill the main tank 104b with ink from the ink cartridge 104a. Refilling the main tank 104b with ink can be performed, for example, by providing a level sensor in the main tank 104b that detects the ink level and based on the output signal from this detection sensor. The level sensor is configured to be able to detect the ink level in multiple stages, for example, five stages. When the ink level detected by the level sensor falls below a first predetermined level, a refill process is executed to refill the main tank 104b with ink, and when the ink level reaches a second predetermined level that is higher than the first predetermined level, the ink refill process is stopped.

[0141] The main tank 104b may be refilled with ink during the startup process, or after the startup process is complete and the printer is ready to print. If ink is to be refilled during the startup process, the ink level is detected in the first step of the process, and the refill process is performed as needed.

[0142] Furthermore, although this is not the original circulation operation, by opening the fifth valve V5 and the eleventh valve V11, ink can be circulated between the second ink path 22, the main tank 104b, and the third ink path 23, making it possible to measure the viscosity of the ink using the viscometer 53.

[0143] The same applies to paths related to the replenishment liquid. For example, by opening the thirteenth valve V13 and the first valve V1, the replenishment liquid contained in the replenishment liquid cartridge 105a is supplied to the main tank 104b, making it possible to adjust the viscosity of the ink stored in the main tank 104b. Furthermore, by opening the ninth valve V9 and the first valve V1, the replenishment liquid mixed with ink stored in the conditioning tank 105b passes through the third replenishment liquid path 33, the first branch portion 51, the sixth ink path 26, the second branch portion 52, and the eighth ink path 28, and is supplied to the main tank 104a.

[0144] The controller 100 also has paths related to air circulation. For example, a first exhaust pipe 41 leading to an exhaust port (not shown) is connected to the main tank 104b. Similarly, a second exhaust pipe 42 leading to the exhaust port is connected to the conditioning tank 105b.

[0145] As another example of a path related to air circulation, the controller 100 has a suction path 27 that connects the nozzle 12 and the first branch portion 51. A sixth valve V6 is provided in the suction path 27, and by opening this sixth valve V6 and the aforementioned fifth valve V5, the nozzle 12 can be connected to the atmosphere via the suction path 27, the first branch portion 51, the sixth ink path 26, the second branch portion 52, the eighth ink path 28, the main tank 104b, and the first exhaust pipe 41. This makes it possible to adjust the ejection pressure of ink droplets ejected from the nozzle 12.

[0146] When printing is performed, ink is supplied from the main tank 104b via the fourth ink path 24 by opening the fourteenth valve V14. The fourteenth valve V14 is provided between the pressure relief valve V2 and the reservoir 12b of the nozzle 12, and is a supply valve that controls the supply of ink to the nozzle 12.

[0147] The fourth ink path 24 of the ink supply unit 104 is provided with a branch path 24a that leads to the main tank 104b. The branch path 24a is provided with a pressure relief valve V2 that is controlled by the control unit 101. When the pressure relief valve V2 is closed by the control unit 101, it maintains the ink pressure in the fourth ink path 24, and when it is opened by the control unit 101, it reduces the ink pressure in the fourth ink path 24. The ink pressure in the fourth ink path 24 can be adjusted by changing the time that the pressure relief valve V2 is open.

[0148] Furthermore, by opening the fourteenth valve V14, the ink supplied via the fourth ink path 24 is converted into ink particles by the vibration force of the vibrator 11 and ejected from the nozzles 12. Of the ink (ink particles) ejected from the nozzles 12, ink that is not involved in printing and replenisher liquid used to clean the nozzles 12, etc., are collected in the gutter 16 and returned to the controller 100 via the fifth ink path 25. In this case, the ink that should be returned to the main tank 104b flows from the first branch portion 51 to the main tank 104b via the sixth ink path 26, the first valve V1 in the second branch portion 52, and the eighth ink path 28. Meanwhile, replenisher liquid sent to the conditioning tank 105b is sent from the fifth ink path 25 via the third valve V3 in the second branch portion 52.

[0149] The collection of ink or replenishment liquid by the gutter 16 is carried out, for example, in connection with the start-up process and shut-down process of the inkjet recording apparatus I. Here, "start-up process" refers to the process that is executed before printing begins when the power to the inkjet recording apparatus I is turned on. On the other hand, "shut-down process" refers to the process that is executed before the operation of the inkjet recording apparatus I is stopped when the power to the inkjet recording apparatus I is turned off.

[0150] More specifically, the inkjet recording apparatus I according to this embodiment does not immediately start printing even when the power switch is turned on. Before starting printing, the inkjet recording apparatus I executes a predetermined start-up process. In this start-up process, the ejection head 1 is cleaned with replenisher liquid, and then ink ejection begins. The ink ejected immediately after the start-up process begins forms the ink axis described above and is collected by the gutter 16.

[0151] Similarly, the inkjet recording apparatus I according to this embodiment does not immediately stop operation when the power switch is turned off. Before stopping operation, the inkjet recording apparatus I performs a predetermined shutdown process, which includes nozzle cleaning. In this shutdown process, replenisher liquid is ejected from the nozzles 12, so that any ink remaining in the nozzles can be washed away and recovered. The ink discharged from the nozzles 12 as a result of the ejection of replenisher liquid is recovered by the gutter 16, similar to the ink shaft in the startup process.

[0152] It should be noted that the "power switch" in this embodiment includes not only a physical push button but also switches configured with a touch-type operation panel displayed on the operation display unit 103, etc. The OFF operation of the power switch refers not only to the operation of physically pressing a push button, etc., but also to a shutdown operation instructed via the operation terminal 800, the operation display unit 103, etc. The same applies to the ON operation of the power switch.

[0153] The start-up process and the shut-down process of the inkjet recording apparatus I will be described in detail below.

[0154] <Basic operation of inkjet recording device I> 9 is a flowchart illustrating the basic operation of the inkjet recording apparatus I. This flowchart illustrates the basic operation of the inkjet recording apparatus I, including the start-up process.

[0155] First, in step SA1 of FIG. 9, the power switch of the inkjet recording apparatus I is turned from OFF to ON, and the inkjet recording apparatus I is powered on.

[0156] In step SA2 following step SA1, the control unit 101 executes a start-up process. As will be described later, a cleaning operation can be performed in the start-up process.

[0157] Fig. 10 is a flowchart illustrating the start-up process of the inkjet recording apparatus I. This flowchart illustrates the details of step SA2 in Fig. 9. That is, four steps SB1, SB2, SB3, and SB4 in Fig. 10 constitute step SA2 in Fig. 9.

[0158] 11 is a diagram for explaining step A in the start-up treatment, FIG. 12 is a diagram for explaining step B in the start-up treatment, and FIG. 13 is a diagram for explaining step C in the start-up treatment.

[0159] In step SB1 of the flowchart shown in Fig. 10, the control unit 101 executes process A to increase the pressure in the ink and replenishment liquid paths in the inkjet recording apparatus I. In this process A, in order to prepare the replenishment liquid, the control unit 101 stands by with the sixteenth valve V16 open and the twelfth valve V12 closed. In this state, the replenishment liquid pump P2 operates, and the replenishment liquid contained in the replenishment liquid cartridge 105a is supplied to the vicinity of the twelfth valve V12 via the first replenishment liquid path 31 (see the thick line in Fig. 11).

[0160] Furthermore, to prepare the ink, the control unit 101 keeps the fourteenth valve V14 closed and on standby. In this state, the ink pump P1 that sends ink to the fourth ink path 24 operates, causing the ink pressure in the fourth ink path 24 to rise (see the thick line in FIG. 11).

[0161] Furthermore, to prepare the gutter 16, the control unit 101 keeps the tenth valve V10 and the first valve V1 open and on standby. In this state, the gutter pump P3 operates, allowing the ink or replenisher liquid collected by the gutter 16 to be sent back to the main tank 104b via the fifth ink path 25 and the second branch portion 52 (see the bold line in FIG. 11).

[0162] In step A, a detection signal from the pressure gauge is input to the control unit 101. Based on the detection signal, the control unit 101 waits until the pressure in the fourth ink path 24 reaches or exceeds a specified value.

[0163] In step SB2, which follows step SB1, the control unit 101 executes step B, causing replenishment liquid to be ejected from the nozzle 12. In step B, the control unit 101 opens the twelfth valve V12, causing replenishment liquid to be sucked out and ejected from the nozzle 12. The ejected replenishment liquid is collected by the gutter 16. Since step B is executed for a short period of less than one second, a smaller amount of replenishment liquid is ejected compared to the other steps. Therefore, the replenishment liquid ejected in step B is sent back to the main tank 104b from the fifth ink path 25 via the first valve V1 (see the thick line in FIG. 12).

[0164] When a large amount of replenishment liquid is ejected in the step B, the third valve V3 is opened instead of the first valve V1, and the replenishment liquid is sent back from the fifth ink path 25 to the conditioning tank 105b.

[0165] In step SB3, which follows step SB2, the control unit 101 executes step C, causing ink to be ejected from the nozzle 12. In this step C, in order to eject ink, the control unit 101 closes the twelfth valve V12 and opens the fourteenth valve V14. This causes a shaft-shaped ink (ink shaft) to be ejected from the nozzle 12. The ejected ink is collected by the gutter 16 and returned to the main tank 104b from the fifth ink path 25 via the first valve V1 (see the bold line in FIG. 13).

[0166] In step SB4, which follows step SB3, the control unit 101 starts vibrating the ink ejected from the nozzle 12 and applying voltage to the charging electrode 13 and the deflection electrode 15. This makes it possible to atomize, charge, and deflect the ink.

[0167] When the process shown in step SB4 is completed, the control process shown in Fig. 10 returns to the control process shown in Fig. 9. Then, the control unit 101 executes step SA3, which follows step SA2. In step SA3, the control unit 101 prints on the workpiece W by causing ink particles (ink grains) to land on the workpiece W.

[0168] Furthermore, since the inkjet recording apparatus I according to this embodiment is a continuous-type inkjet printer, when it is in a printable state after start-up processing (the operating state of the inkjet recording apparatus I), ink continues to be ejected from the nozzles 12 even when printing is not being performed. The ink ejected at this time is not deflected by the deflection electrodes 15 (in other words, it is "non-deflected"). The non-deflected ink does not participate in printing, but is collected by the gutter 16, circulated within the apparatus, and reused.

[0169] When printing is completed and the inkjet recording apparatus I is shut down normally, the power switch of the inkjet recording apparatus I is switched from ON to OFF in step SA3. In this case, the process proceeds to step SA4, where the control unit 101 executes shutdown processing. A cleaning operation can also be executed during this shutdown processing.

[0170] Fig. 14 is a flowchart illustrating the shutdown process of the inkjet recording apparatus I. This flowchart illustrates the details of step SA4 in Fig. 9. That is, five steps SC1 to SC5 in Fig. 14 constitute step SA4 in Fig. 9.

[0171] Also, FIG. 15 is a diagram for explaining step D in the falling-down treatment, FIG. 16 is a diagram for explaining step E in the falling-down treatment, and FIG. 17 is a diagram for explaining step F in the falling-down treatment.

[0172] 14, the control unit 101 stops vibrating the ink ejected from the nozzle 12 and stopping the application of voltage to the charging electrode 13 and the deflection electrode 15 (ink atomization, charging, deflection: ON→OFF). This stops the ink atomization, charging, and deflection, and causes a shaft-shaped ink shaft to be ejected from the nozzle 12.

[0173] In step SC2, which follows step SC1, the control unit 101 stops the ink ejection from the ink shaft (stopping ink ejection). Specifically, in step SC2, in order to stop ink ejection, the control unit 101 closes the fourteenth valve V14. This prevents ink from being ejected from the nozzles 12.

[0174] In step SC3 following step SC2, the control unit 101 alternately executes step D illustrated in FIG. 15 and step E illustrated in FIG. 16 to intermittently eject the replenisher liquid. By intermittently ejecting the replenisher liquid, the inkjet recording apparatus I, and in particular the nozzles 12, can be cleaned. Hereinafter, this operation will be referred to as the "intermittent ejection operation."

[0175] 15, the control unit 101 opens the sixteenth valve V16, the twelfth valve V12, the tenth valve V10, and the first valve V1. In this state, the control unit 101 operates the replenishment liquid pump P2 and the gutter pump P3, causing the replenishment liquid contained in the replenishment liquid cartridge 105a to be ejected from the nozzles 12 via the first replenishment liquid path 31 and collected by the gutter 16. The replenishment liquid collected by the gutter 16 is returned to the main tank 104b via the fifth ink path 25 and the second branch portion 52 (see the bold line in FIG. 15).

[0176] Immediately after starting the process shown in Figure 14, it is believed that a large amount of ink remains in the fifth ink path 25, so the replenishment liquid in step D shown in Figure 15 is sent back to the main tank 104b rather than the conditioning tank 105b.

[0177] 16, the control unit 101 closes the twelfth valve V12 and opens the sixth valve V6. Then, due to the negative pressure exerted by the circulation pump P4, the refill liquid remaining in the nozzles 12 is sucked into the main tank 104b via the suction path 27, the first branch part 51, the sixth ink path 26, the first valve V1, and the eighth ink path 28 (see the thick line in FIG. 16).

[0178] 16, the twelfth valve V12 may be left open instead of being closed. In this case, while the replenishment liquid is supplied from the replenishment liquid cartridge 105a to the nozzle 12, the supplied replenishment liquid is sucked directly from the suction path 27. This improves the flow rate of the replenishment liquid flowing through the sixth valve V6, enabling more thorough cleaning.

[0179] 15 and step E shown in Fig. 16 are repeated multiple times (for example, several sets). Here, the time for performing step D in step SC3 (for example, less than 1 second) is shorter than the time for performing step E (for example, about several seconds).

[0180] Furthermore, after closing the twelfth valve V12 in step E, the twelfth valve V12 is opened in step D, so that the replenisher liquid is intermittently sprayed. The twelfth valve V12 may be closed for several seconds when transitioning from step D to step E. This increases the pressure of the replenisher liquid near the twelfth valve V12, and when the twelfth valve V12 is opened, the replenisher liquid can be ejected with force.

[0181] 15, and causes replenishment liquid to be ejected from the nozzles 12. The time required to perform step D in step SC4 is, for example, about 30 seconds, which is longer than the time required to perform step D in step SC3. By performing step SC4, it is possible to mainly clean the fifth ink path 25 leading to the gutter 16.

[0182] In step SC5, which follows step SC4, the control unit 101 executes step F shown in FIG. 17 to recover replenishment liquid from the ejection head 1. Specifically, in step F, the control unit 101 opens the tenth valve V10 and the third valve V3. In this state, the gutter pump P3 operates, and the replenishment liquid remaining in the nozzles 12 is sucked into the conditioning tank 105b via the fifth ink path 25 and the second branch portion 52 (see the thick line in FIG. 17). By executing step SC5, the replenishment liquid used for cleaning can be recovered.

[0183] Because the replenisher liquid was discharged in step SC4 before step SC5 was executed, it is believed that a relatively large amount of replenisher liquid remains in the fifth ink path 25. For this reason, the replenisher liquid in process F is sent back to the conditioning tank 105b, not to the main tank 104b.

[0184] When the processing shown in step SC5 is completed, a return is made, and the control process returns from the control process shown in Fig. 14 to the control process shown in Fig. 9. Then, in step SA5 following step SA4, the power supply to the inkjet recording apparatus I is cut off, and the inkjet recording apparatus I stops its operation.

[0185] (Viscosity adjustment treatment) As the solvent in the ink in the main tank 104b evaporates over time, the proportion of solids increases, and the viscosity of the ink in the main tank 104b increases. In this embodiment, the system is configured to be able to execute a viscosity adjustment process to adjust the viscosity of the ink in the main tank 104b. The viscosity adjustment process is executed continuously from the completion of the start-up process in step SA2 of the flowchart shown in FIG. 9 until the completion of the shut-down process in step SA4.

[0186] An example of the viscosity adjustment process will be described with reference to the flowchart shown in Fig. 18. This flow may be started after the above-described process of refilling ink into the main tank 104b has been performed as needed, or may be started when a predetermined time has elapsed since the start of operation.

[0187] In step SD1 after the start, the viscosity of the ink in the main tank 104b is measured using the viscometer 53 shown in FIG. 8. In step SD2, the control unit 101 opens the fifth valve V5 and the eleventh valve V11 shown in FIG. 4 to circulate ink between the second ink path 22, the main tank 104b, and the third ink path 23. This circulation operation supplies ink in the main tank 104b to the H level in the upper container 53a, as shown in FIG. 8. The ink level in the upper container 53a can be detected by a sensor (not shown), and the control unit 101 controls the valves V5 and V11 to stop the supply of ink to the upper container 53a when the ink level in the upper container 53a reaches the H level (step SD3).

[0188] Next, in step SD4, the time from immediately after the ink supply is stopped until the ink level in the upper container 53a falls below the L level is measured. The relationship between the time until the ink level falls below the L level and the ink viscosity can be obtained in advance by testing or the like, so by using the viscometer 53, the ink viscosity can be calculated based on the time measurement results (step SD5). The ink viscosity calculated by the viscometer 53 is output to the control unit 101. Note that the viscometer 53 is just an example, and the ink viscosity may also be measured using other sensors or the like.

[0189] In step SD6, the difference between the measured viscosity calculated in step SD5 and the target viscosity is calculated, and it is determined whether the difference is equal to or greater than a predetermined value. The target viscosity is a viscosity at which high-quality printing can be performed normally, and can be obtained in advance by testing or the like and stored in advance in memory unit 102 or the like. The predetermined value in step SD6 can be set to, for example, 0.1 cP or 0.2 cP, but is not limited to this.

[0190] If step SD6 returns NO and the difference between the measured viscosity and the target viscosity is less than the predetermined value, the ink in main tank 104b has a viscosity that allows high-quality printing to be performed normally. In this case, the process returns to step SD1, and steps SD2 to SD6 are executed. On the other hand, if step SD6 returns YES and the difference between the measured viscosity and the target viscosity is equal to or greater than the predetermined value, the viscosity of the ink in main tank 104b is too high, and the process proceeds to step SD7.

[0191] In step SD7, the control unit 101 opens the thirteenth valve V13 and the first valve V1. This causes the replenisher liquid stored in the replenisher liquid cartridge 105a to be supplied to the main tank 104b. The amount of replenisher liquid supplied to the main tank 104b in one step SD7 may be set so that the viscosity does not fall below the target viscosity. The amount of replenisher liquid supplied in step SD7 may be set based on the actual viscosity calculated in step SD5; the higher the actual viscosity, the greater the amount of replenisher liquid supplied.

[0192] Then, the process proceeds to step SD8. In step SD8, a predetermined time is waited until the viscosity of the ink in the main tank 104b stabilizes. In other words, immediately after supplying replenisher liquid, the viscosity may vary depending on the location within the main tank 104b. Therefore, by waiting a certain amount of time until the viscosity of the ink in the main tank 104b becomes uniform, the subsequent processes of steps SD1 to SD6 can be performed accurately. In this way, the viscosity of the ink in the main tank 104b can be adjusted to fall within a predetermined range after the start-up process, so the solubility of the ink colorant and binder can be maintained at a good level, achieving high print quality and preventing defects from occurring.

[0193] Therefore, the control unit 101 of this embodiment is a part that executes viscosity adjustment processing that controls the flow rates of ink supplied to the main tank 104b via the ink receiver 104d and replenisher liquid supplied to the main tank 104b via the replenisher liquid receiver 105d so that the viscosity of the ink in the main tank 104b falls within a predetermined range, based on the viscosity of the ink in the main tank 104b measured by the viscometer 53. Note that if the start-up processing starts during the viscosity adjustment processing, the control unit 101 interrupts this flow and executes the start-up processing.

[0194] In this embodiment, as described above, the ink solvent is a mixed solvent containing ketone and alcohol, and alcohol is more volatile than ketone. Therefore, if a replenisher liquid is used containing ketone and alcohol in the same ratio as the ink solvent, the ketone concentration in the ink in the main tank 104b after repeated viscosity adjustment processes will be higher than the initial concentration.

[0195] For example, as shown in FIG. 19, if the ketone concentration in the ink solvent is 50 percent by mass and the ketone concentration in the replenisher is 50 percent by mass, and the viscosity adjustment process is continued for a long period of time, the ketone concentration in the ink solvent in the main tank 104b will rise to 65 percent by mass if the ambient temperature of the main tank 104b is 40°C, 55-57 percent by mass if the ambient temperature is 35°C, 59-62 percent by mass if the ambient temperature is 25°C, and 54 percent if the ambient temperature is 0°C. After that, the ketone concentration reaches equilibrium. This equilibrium state refers to a state in which the ketone concentration in the ink solvent in the main tank 104b does not change any further even if the viscosity adjustment process is continued.

[0196] Inkjet recording apparatus I is designed to operate normally at the initial concentration, but if ink containing ketone at a concentration higher than the initial concentration is used as shown in Figure 19, there is a concern that unintended malfunctions may occur. Malfunctions of inkjet recording apparatus I include, for example, swelling of the rubber used as a sealant in inkjet recording apparatus I, and nozzle clogging due to ink precipitation.

[0197] While the ketone concentration of the ink in the main tank 104b gradually increases as the viscosity adjustment process is repeated, in this embodiment, instead of using a ketone and alcohol replenisher in the same ratio as the ink solvent in the ink cartridge 104a, the mass percentage concentration of ketone in the replenisher is set lower than the mass percentage concentration of ketone in the ink solvent in the ink cartridge 104a.

[0198] For example, as shown in Figure 20, when the mass percent concentration of ketone in the ink solvent of ink cartridge 104a is set to 74 mass percent and the mass percent concentrations of ketone in the replenisher are set to 70 mass percent, 66 mass percent, and 62 mass percent, the inventors have found that the mass percent concentration of ketone in the ink solvent converges to a range of +10 to +12 points of the mass percent concentration of ketone in the replenisher over a wide ambient temperature range from 0 to 40°C. The "concentration difference" in Figure 20 is the saturated ketone concentration of the ink minus the ketone concentration in the replenisher.

[0199] 20, it is possible to determine the ketone concentration of the replenisher liquid that can stabilize the ketone concentration in the ink solvent of the ink cartridge 104a within a certain range. This also makes it easy to design high-performance ink solutions, such as the solubility of the ink after drying, and to determine the degree of swelling of the rubber sealant used in the inkjet recording apparatus I.

[0200] In short, by making the mass percentage concentration of the ketone in the replenisher liquid 8 to 12 points lower than the mass percentage concentration of the ketone in the ink solvent in the ink cartridge 104a, the ketone concentration in the ink solvent in the ink cartridge 104a can be maintained at or near the initial concentration s. In other words, when the inkjet recording apparatus I is operating within a predetermined ambient temperature range (0 to 40°C), the ketone concentration in the replenisher liquid is lower in mass percentage concentration than the ketone concentration in the ink solvent in the ink cartridge 104a so that the ketone concentration in the solvent in the main tank 104b is maintained within ±1 point of the initial concentration, even if the viscosity of the ink in the main tank 104b is adjusted multiple times.

[0201] Furthermore, in this embodiment, the ketone concentration in the replenisher is set to be 5 to 15 mass percentage points lower than the ketone concentration in the ink solvent contained in the ink cartridge 104a. This allows the ketone concentration in the ink solvent contained in the ink cartridge 104a to be maintained at or near the initial concentration. This reduces the risk of the solids not dissolving completely and precipitating, even for high-performance inks with a high solids content. For example, in the case of a mixed solvent of ketone and a relatively readily available alcohol such as ethanol, even if the replenisher contains a high proportion of the relatively readily available alcohol, the risk of the solids not dissolving completely and precipitating in the main tank 104b of the inkjet recording apparatus I is reduced. Examples of high-performance inks that can be used include inks that use a mixed solvent of diethyl ketone, a solvent that is not subject to the Organic Solvent Law and has a relatively high allowable concentration, and readily available denatured ethanol, and alcohol-resistant, highly adhesive inks with low alcohol solubility and thick coating thicknesses.

[0202] From another perspective, the ketone concentration of the replenisher liquid is set 5 to 15 mass percentage points lower than the ketone concentration in the ink solvent contained in the ink cartridge 104a. This allows the ketone concentration in the ink solvent in the ink cartridge 104a to be maintained at or near the initial concentration, thereby avoiding a shortened rubber sealant lifespan and enabling stable use of high-performance inks, such as highly alcohol-resistant inks. In other words, if the ketone concentration is less than 5 mass percentage points, the initial ketone concentration in the ink solvent increases, necessitating ink and rubber sealant designs that accommodate a wide range of ketone concentrations. However, these design requirements often cannot be met, resulting in reduced sealant lifespan and ink stability. On the other hand, if the ketone concentration is greater than 15 mass percentage points, the ketone concentration may decrease significantly, potentially resulting in the solids of highly functional inks, such as highly alcohol-resistant inks, not being fully dissolved and resulting in precipitation. When a stable ink is required, prioritizing solubility may be necessary, compelling ink performance, such as alcohol resistance, to be compromised.

[0203] (Management Department) As shown in FIG. 2, the control unit 101 is provided with a management unit 101a that regulates at least one of the receipt of ink via the ink receiving unit 104d and the receipt of replenishment liquid via the replenishment liquid receiving unit 105d.

[0204] That is, as described above, in order to maintain the ketone concentration of the solvent in main tank 104b at or near the initial concentration, the ketone concentration of the ink solvent in ink cartridge 104a and the ketone concentration of the replenisher liquid in replenisher liquid cartridge 105a are important, and if these ketone concentrations differ from what was expected, the ketone concentration of the solvent in main tank 104b will deviate from the initial concentration. To prevent this, management unit 101a is provided.

[0205] When supplying ink from the ink cartridge 104a, the management unit 101a executes the process shown in the flowchart of Figure 21. At the start, step SE1, it is determined whether the ink installation detection switch 104f is ON. If the determination is NO and the ink installation detection switch 104f is OFF, it means that the ink cartridge 104a has not been accepted by the ink receiving unit 104d, and the process waits until it is ON. If the determination is YES and the ink installation detection switch 104f is ON, it means that the ink cartridge 104a has been accepted by the ink receiving unit 104d, and the process proceeds to step SE2. At step SE2, the ink information access unit 104g accesses the ink information storage unit 104e to read information about the ink.

[0206] Next, the process proceeds to step SE3, where the ketone concentration in the ink solvent in ink cartridge 104a is estimated based on the ink-related information read in step SE2. For example, the ketone concentration in the ink solvent supplied may change due to variations in the solvent mixture or evaporation after production, and this is corrected in step SE3. Specifically, as shown in FIG. 7A, the ink-related information includes the manufacturing date, and the manufacturing date is compared with the current date. The older the manufacturing date, the lower the concentration of alcohol, which is more volatile than ketone, and the higher the ketone concentration. Therefore, the older the manufacturing date, the higher the ketone concentration. Therefore, the correction is performed in step SE3 so that the ketone concentration increases with the manufacturing date. The amount of correction can be obtained in advance through experiments, etc.

[0207] The information about the ink also includes the ketone concentration of the ink solvent when it was filled into ink cartridge 104a. Based on this ketone concentration and the manufacturing date, the ketone concentration of the ink solvent currently in ink cartridge 104a can be corrected and estimated in step SE3.

[0208] In step SE4, it is determined whether the ketone concentration in the ink solvent in ink cartridge 104a estimated in step SE3 is within a predetermined range or outside of the predetermined range. The predetermined range can be, for example, 74 to 78 mass percent. If the ketone concentration is outside this range, the process proceeds to step SE6, where error processing is performed and ink supply, i.e., ink reception, is restricted. On the other hand, if it is determined in step SE3 that the ketone concentration in the ink solvent in ink cartridge 104a estimated is within the predetermined range, the process proceeds to step SE5, where ink reception is not restricted. In this case, ink can be sucked from ink cartridge 104a and supplied to main tank 104b as needed.

[0209] Furthermore, when supplying the replenishment liquid in the replenishment liquid cartridge 105a, the management unit 101a executes the processing shown in the flowchart of FIG. 22. In the start step SF1, it is determined whether the replenishment liquid installation detection switch 105f is ON. If the determination is NO and the replenishment liquid installation detection switch 105f is OFF, it means that the replenishment liquid cartridge 105a has not been received by the replenishment liquid receiving unit 105d, and the process waits until it is ON. If the determination is YES and the replenishment liquid installation detection switch 105f is ON, it means that the replenishment liquid cartridge 105a has been received by the replenishment liquid receiving unit 105d, and the process proceeds to step SF2. In step SF2, the replenishment liquid information access unit 105g accesses the replenishment liquid information storage unit 105e to read information about the replenishment liquid.

[0210] Then, proceeding to step SF3, the ketone concentration of the replenisher liquid in the replenisher liquid cartridge 105a is estimated based on the information about the replenisher liquid read in step SF2. For example, the ketone concentration of the supplied replenisher liquid may change due to variations in the solvent mixture or evaporation after production, and this change is corrected. As shown in FIG. 7B, the information about the replenisher liquid includes the manufacturing date, so the correction is made so that the ketone concentration increases with the manufacturing date. The amount of correction can be obtained in advance by experimentation, etc.

[0211] The information about the replenisher liquid also includes the ketone concentration of the replenisher liquid when it was filled into the replenisher liquid cartridge 105a. Based on this ketone concentration and the manufacturing date, the ketone concentration of the replenisher liquid currently in the replenisher liquid cartridge 105a can be corrected and estimated.

[0212] In step SF4, it is determined whether the ketone concentration of the replenisher liquid in the replenisher liquid cartridge 105a estimated in step SF3 is within a predetermined range or outside the predetermined range. The predetermined range can be, for example, 10 to 12 mass percent concentration. If the ketone concentration is outside this range, the process proceeds to step SF6, where error processing is performed and the supply of replenisher liquid, i.e., the receipt of replenisher liquid, is restricted. On the other hand, if it is determined that the ketone concentration of the replenisher liquid in the replenisher liquid cartridge 105a estimated in step SF3 is within the predetermined range, the process proceeds to step SF5, where the replenisher liquid in the replenisher liquid cartridge 105a is aspirated and supplied to the main tank 104b as necessary.

[0213] (Suppresses swelling of rubber seal materials) As the ketone concentration in the ink solvent increases, the amount of swelling of the rubber sealant used in the inkjet recording apparatus I increases, which may shorten its lifespan, so as mentioned above, the ketone concentration in the ink solvent is maintained at or near the initial concentration. Meanwhile, the present inventors have considered the relationship between the proportion of solids (non-solvent components) in the ink and the amount of swelling of the rubber sealant and have found that increasing the proportion of solids reduces the amount of swelling of the rubber sealant.

[0214] As shown in Figure 23, when the ink solvent ketone / alcohol ratio is set to 70:30 and the solids content is changed to 0%, 10%, and 20%, the weight change rate of the sealant (equivalent to the amount of swelling of the sealant) decreases. Here, diethyl ketone was selected as the ketone and EPDM was selected as the sealant. Based on the results shown in Figure 23, as shown in Figure 24, even if the ketone concentration in the ink solvent becomes high, increasing the solids content can reduce the ketone concentration in the ink as a whole, thereby suppressing the amount of swelling of the sealant and making it approximately equal to the amount of swelling in the replenisher. This prevents a shortening of the sealant's lifespan.

[0215] (Modification of start-up process) During startup or printing, a small amount of ink may adhere to the nozzles 12 and deflection electrodes 15, resulting in printing disturbances. Furthermore, if the device is left turned off for an extended period of time, the ink may become highly viscous due to evaporation and accumulate in the flow paths, potentially causing poor ink suction. To prevent this, the nozzles 12 and deflection electrodes 15 are cleaned with replenisher liquid, as described above. However, if the replenisher liquid used for cleaning is allowed to flow into the main tank 104b, the ketone concentration in the ink solvent in the main tank 104b may fluctuate by approximately 5 to 10%, even though the fluctuation rate of the ketone concentration at the equilibrium point during the viscosity adjustment process is within ±1%.

[0216] In response to this, in this embodiment, for example, after the cleaning process is performed, the cleaning liquid is collected in the conditioning tank 105b, and control is performed to prevent excessive replenishment liquid from flowing into the main tank 104b. Similar control can be performed when the ink axis is adjusted.

[0217] The control details will be explained below based on the flowchart in FIG. 25. In step SG1 after starting, it is determined whether or not residual liquid recovery is necessary. If, for example, a cleaning process was performed before entering the processing of this flowchart, it is determined that residual liquid recovery is necessary. Also, if, for example, an ink axis adjustment was performed before entering the processing of this flowchart, it is determined that residual liquid recovery is necessary. If the determination is YES and residual liquid recovery is necessary, the process proceeds to step SG2, where the residual liquid is recovered from the fifth path 25 via the third valve V3 in the second branch section 52 into the conditioning tank 105b. Thereafter, the process proceeds to step SG3, where the normal start-up process described above is executed. If the determination is NO in step SG1, the process also proceeds to step SG3, where the normal start-up process described above is executed.

[0218] (Treatment to prevent print quality degradation and nozzle clogging due to ink deposits) When an alcohol-resistant ink contains ethanol, as in the ink of this embodiment, the solubility margin is reduced, and therefore minute amounts of precipitates may form due to subtle disturbances such as a drop in ambient temperature or long-term storage. Even if the amount of precipitate is minute, if it reaches the nozzle 12, it can significantly change the timing of ink particle depletion locally, resulting in a significant reduction in print quality. Furthermore, if the degree of precipitation is large, the nozzle 12 may become clogged.

[0219] Although trace amounts of precipitates can be filtered out by filter F shown in Figure 4, etc., the liquid on the secondary side of filter F is discharged in the early stages after the start-up process is completed. If the system is left unused for a long period of time, the liquid on the secondary side of filter F may have been filtered for a long time, which can cause the above-mentioned phenomenon.

[0220] To prevent print quality degradation and nozzle clogging due to ink deposits, the control unit 101 executes a start-up process according to another modified example shown in the flowchart of FIG. 26. After starting, in step SH1, ink is circulated and filtered through filter F without being ejected from the nozzles 12. The ink flow rate during circulation is set higher than that for printing, allowing deposits to be filtered out quickly. Then, in step SH2, the nozzles 12, deflection electrodes 15, etc. are cleaned with replenisher liquid. Then, the process proceeds to step SH3, where the normal start-up process described above is executed.

[0221] Step SH1 may be started, for example, when the ambient temperature becomes equal to or lower than a predetermined temperature, or when the time elapsed since the power was turned off is equal to or longer than a predetermined time.

[0222] (Effects of the embodiment) As described above, according to this embodiment, printing is performed on the workpiece W using ink containing 15% or more by mass of solids. This increases the coating thickness of the ink after drying, making it easier to improve adhesion. In this case, since the coating thickness is increased to reinforce adhesion, it is possible to use solids in the ink that do not meet the desired adhesion when the coating is thin. If a solid that forms a coating that is difficult to dissolve in alcohol is used as the solid, the ink's alcohol resistance after drying is increased, and peeling of the ink when, for example, disinfectant alcohol is adhered to the ink is suppressed. Furthermore, by including 15% or more by mass of solids in the ink, it is easy to design high-performance inks with reinforced adhesion.

[0223] In addition, ink costs can be reduced by using ink containing a two-component mixed solvent, which is a mixture of ketone and relatively inexpensive alcohol. If the viscosity of the ink in the main tank 104b increases over time due to solvent evaporation, replenisher liquid is sent to the main tank 104b and mixed with the ink to adjust the ink viscosity. Because the mass percentage concentration of ketone in the mixed replenisher liquid is lower than the mass percentage concentration of ketone in the ink solvent, the ratio of ketone in the solvent after viscosity adjustment approaches the initial ratio. This makes it less likely that the ratio of ketone in the solvent will change over time. This reduces the likelihood of unintended device malfunctions.

[0224] The above-described embodiments are merely examples in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention. [Industrial Applicability]

[0225] As described above, the present invention can be used when printing on various printing objects, for example. [Explanation of symbols]

[0226] 1 Discharge head 21 First ink path 22 Second ink path 25 5th ink path (recovery path) 32 Second replacement fluid path 53 Viscometer 101 Control section 101a Management Department 104b Main tank (mixing vessel) 104c Ink distribution channel 104d Ink receiving section 104e Ink information storage unit (first storage medium) 104g Ink information access section (first access section) 105d Replenishment fluid receiving section 105e Replacement fluid information storage unit (second storage medium) 105g Refill information access section (second access section) I Inkjet recording device

Claims

1. A refill cartridge for use in a continuous inkjet recording device that prints on a printing object using printing ink prepared by mixing a refill liquid with ink containing 15 mass percent or more solids including an ink colorant and a binder, and a solvent in which one or more ink-dissolving ketones selected from the group including diethyl ketone, methyl isopropyl ketone, and methyl propyl ketone are mixed with an alcohol having a higher volatility than the ink-dissolving ketones, The container contains one or more replenisher ketones selected from the group consisting of diethyl ketone, methyl isopropyl ketone, and methyl propyl ketone, and an alcohol having a higher volatility than the replenisher ketone, A refill liquid cartridge, characterized in that the mass percent concentration of the refill ketone is lower than the mass percent concentration of the ink-dissolving ketone in the solvent of the ink.

2. 2. The replenisher cartridge according to claim 1, A replenishment liquid cartridge comprising a replenishment liquid information storage section for storing information about contents of the replenishment liquid cartridge in a format readable by the inkjet recording device.

3. 3. The replenisher cartridge according to claim 2, The replenishment liquid cartridge is characterized in that the replenishment liquid information storage unit stores the ketone concentration or remaining amount of the contained contents as information about the contained contents.

4. 4. The refill cartridge according to claim 3, A refill liquid cartridge, wherein the ketone concentration of the content is numerical data obtained by measuring the ketone concentration before filling the content into the refill liquid cartridge.

5. 5. The refill liquid cartridge according to claim 2, The replenishment liquid cartridge is characterized in that the replenishment liquid information storage section is made of a nonvolatile memory that stores information about the contents.

6. 6. The refill cartridge according to claim 1, the inkjet recording device comprises a discharge head that discharges printing ink toward a printing object, and a controller that sends a control signal to the discharge head and supplies replenishment liquid to the discharge head; The refill liquid cartridge is configured to be detachable from the controller.

7. 7. The replenisher cartridge according to claim 6, the controller of the inkjet recording device includes a replenishment liquid receiving section for receiving replenishment liquid; The replenishment liquid cartridge is configured to be receivable in the replenishment liquid receiving portion.

8. An ink cartridge used in a continuous inkjet recording device that prints on a printing object using printing ink prepared by mixing ink and a replenisher liquid, a solids content of 15 weight percent or more, including ink colorants and binders; a solvent containing one or more ink-dissolving ketones selected from the group consisting of diethyl ketone, methyl isopropyl ketone, and methyl propyl ketone, and an alcohol having a higher volatility than the ink-dissolving ketone; An ink cartridge characterized in that, for a replenisher liquid containing one or any two or more replenisher ketones selected from the group consisting of diethyl ketone, methyl isopropyl ketone, and methyl propyl ketone, and an alcohol having higher volatility than the replenisher ketone, the mass percentage concentration of the ink-dissolving ketone in the solvent is higher than the mass percentage concentration of the replenisher ketone in the replenisher liquid.

9. 9. The ink cartridge according to claim 8, An ink cartridge, characterized in that the solid content contained in the ink cartridge has an alcohol solubility of 5% or less after being ejected from the inkjet recording device, adhering to a printing target, and drying.

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