KR20240010408A - Recording apparatus - Google Patents

Abstract

[Task] Suppressing the disposal of unnecessary liquids
[Solution means] A recording device includes a recording head that performs recording by ejecting ink containing a light-emitting material, and detection means that optically detects the state of functionality related to light emission of the ink.

Description

RECORDING APPARATUS}

The present invention relates to a recording device.

In an inkjet type recording device, it is known to attempt to restore ejection performance by performing recovery operations such as flushing, pressurizing, and suction operations on the recording head. Additionally, Patent Document 1 proposes a recording device that reuses the ink discharged from the recording head during this recovery operation.

Japanese Patent No. 5954276

However, in recording devices, there are cases where functional ink containing a luminescent material is used. Such ink deteriorates when it comes into contact with moisture or oxygen in the air. Therefore, for example, ink near the nozzle in the recording head or ink discharged from the recording head through a recovery operation as performed in the above-mentioned prior art, etc. tend to be relatively prone to deterioration.

Additionally, if recording is performed using ink that has deteriorated, there is a risk that the recorded material may not exhibit the desired performance, so the ink that has deteriorated needs to be discarded. On the other hand, discarding ink that has not deteriorated enough to require disposal may lead to an increase in ink consumption.

The present invention provides a technology that can suppress waste of unnecessary liquid.

According to the present invention,

a recording head that performs recording by ejecting ink containing a luminescent material;

A recording device is provided, comprising detection means for optically detecting the state of functionality related to light emission of the ink.

According to the present invention, waste of unnecessary liquid can be suppressed.

1(a) and 1(b) are schematic diagrams showing the configuration of a recording device according to one embodiment.
Fig. 2 is a control block diagram showing the control configuration of a recording device according to one embodiment.
3(a) and 3(b) are schematic diagrams showing the configuration of a recording head and a recovery unit according to one embodiment.
Fig. 4 is a diagram for explaining the configuration of an ink flow path of a recording device according to one embodiment.
Figure 5 is a schematic diagram showing the configuration of a detection unit according to one embodiment.
Figure 6 is a diagram showing the relative irradiation intensity of inspection light of the detection unit according to one embodiment.
Figure 7 is a flowchart showing an example of CP processing according to one embodiment.
Fig. 8 is a flowchart showing an example of CP processing according to one embodiment.
Fig. 9 is a flowchart showing an example of CP processing according to one embodiment.
Figure 10 is a diagram showing the relationship between the absorption spectrum of an ultraviolet curing initiator and the emission spectrum of inspection light in Examples and Comparative Examples.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In addition, the following embodiments do not limit the invention related to the scope of the patent claims. Although a plurality of features are described in the embodiments, not all of these features are essential to the invention, and the plural features may be arbitrarily combined. Moreover, in the accompanying drawings, the same reference numerals are attached to the same or the same components, and duplicate descriptions are omitted.

[First embodiment]

<Overview of recording devices>

1(a) and 1(b) are schematic diagrams showing the configuration of a recording device 1 according to one embodiment. In addition, Figure 1(a) is a top view of the recording device 1, and Figure 1(b) is a side view of the recording device 1. For convenience, the elements of the recording device 1 necessary for explanation of the present embodiment are shown. It shows the bay. Additionally, the ink supply system and recovery system mechanisms will be described later.

The recording device 1 is an inkjet recording device. The recording device 1 of this embodiment performs recording by ejecting functional ink onto the substrate 11.

Functional ink is said to refer to a liquid containing functional materials. In this embodiment, the functional ink contains a light-emitting material such as a phosphorescent material or a fluorescent material as a functional material. Such functional ink can be used, for example, to form an organic light-emitting layer used in an organic EL (Electro Luminescence) display or a quantum dot color conversion layer. For example, in the formation of an organic light-emitting layer, a color display is formed by forming the organic light-emitting layer using organic light-emitting materials that emit light in each color of red, green, and blue. Additionally, in this embodiment, the functional ink contains an ultraviolet curing initiator. In addition, the substrate 11 is, for example, a glass substrate, but may be another substrate such as a film substrate, or may be a sheet-shaped recording medium such as paper. In other words, the recording object of the recording device 1 is not particularly limited. In addition, hereinafter, functional ink may be simply referred to as ink.

The recording device 1 includes a recording head 2, a scanning mechanism 4, a base 9, and a stage 10.

The recording head 2 discharges ink onto the substrate 11 to perform recording. As will be described in detail later, a plurality of nozzles 3 (see Fig. 3(a)), not shown, are arranged in the recording head 2 in a direction opposite to the substrate 11. A pressure generator (not shown) using deformation of the piezo element or film boiling of the heating element is connected to the nozzle 3, and the ink in the nozzle is thereby discharged. Additionally, in this embodiment, the nozzles 3 are arranged on the recording chip 100 as will be described later.

The scanning mechanism 4 is a mechanism capable of scanning the recording head 2 in the horizontal direction (XY direction). The scanning mechanism 4 includes a main injector 5 that carries the recording head 2, a main scanning guide rail 6 that guides the main injector 5 along the main scanning direction (Y direction), and a main scanning guide rail 6 that guides the main injector 5 along the main scanning direction (Y direction). It includes a sub-scan guide rail 7 that guides the guide rail 6 along the sub-scan direction (X direction). By means of the scanning mechanism 4, the recording head 2 can scan an area parallel to the XY plane. For example, the main injector 5 is movable in the main scanning direction with respect to the main scanning guide rail 6 by a driving source such as a motor (not shown), and the main scanning guide rail 6 is moved by a driving source such as a motor. It is possible to move in the sub-scan direction with respect to the sub-scan guide rail 7 by (not shown).

The base 9 supports each element of the recording device 1. The stage 10 is fixed on the base 9, and the substrate 11 to be recorded is set thereon. Additionally, the recording head 2 and the substrate 11 may be relatively movable, or the recording head 2 may be fixed and the substrate 11 may be moved. Additionally, the broken lines in Figures 1(a) and 1(b) conceptually represent the ink path and do not represent physical connections. Additionally, as will be described in detail later, a detection unit 108 is installed in this ink path.

<Control Configuration>

Figure 2 is a control block diagram showing the control configuration of the recording device 1. In addition, for convenience of explanation, only elements related to the explanation of this embodiment are shown as the control circuit 300 in FIG. 2 .

CP301 controls the entire recording device 1. For example, CPU 301 controls the entire system by reading and executing the program stored in RV 302. In other words, information processing using software stored in the ROM 302 is concretely realized by the CPU 301, which is an example of hardware, so that the control circuit 300 can execute each function. At this time, CPU 301 develops a program in RM 312 and uses it as a work area. In other words, the RM 312 temporarily stores data and input data necessary for processing performed by the CPU 301. Additionally, the recovery control unit 304 controls the recovery unit 114 (see Fig. 3(a)) and the like to perform a recovery operation of the recording head 2. The transport control unit 303 controls the scanning mechanism 4 to transport the recording head 2.

Furthermore, CPU 301 also controls recording operation by recording head 2 through drive circuit 307, binarization circuit 308, and image processing unit 309. The image processing unit 309 performs predetermined image processing on the input image data to be recorded. In other words, the image processing unit 309 records the RGBD image recorded by the recording device 1 based on information such as the input pixel size, pixel spacing, and film thickness required for each pixel of the input substrate 11, for example. Execute conversion to data. The binary conversion circuit 308 performs halftone processing on the multi-level density image data converted by the image processing unit 309, and then converts it into binary data (bitmap data). Then, the drive circuit 307 causes the recording head 2 to execute an ink droplet ejection operation in accordance with the binary data obtained by the binary conversion circuit 308, etc.

Additionally, the CPU 301 controls the circulation of ink in the ink circulation passage, which will be described later, by the circulation control unit 313. In addition, the CPU 301 controls the detection of the state of functionality related to the emission of ink by the detection unit 108 by the detection control unit 314.

<Recording head and recovery unit>

3(a) and 3(b) are schematic diagrams showing the configuration of the recording head 2 and the recovery unit 114. Additionally, Figure 3(a) is a top view and Figure 3(b) is a side view. In this embodiment, the recording head 2 includes a recording unit 113 that discharges ink to perform recording. Additionally, corresponding to the recording unit 113, a recovery unit 114 is installed.

The recording unit 113 includes a plurality of recording chips 100. On the recording chip 100, a plurality of nozzles 3 are arranged. For example, it is assumed that each recording chip 100 has 256 nozzles 3 arranged in 4 rows. In the recording unit 113, four recording chips 100 are arranged in a zigzag arrangement. Additionally, a flow path 110 for supplying ink is connected to the recording unit 113. The flow path 110 is formed by flow forming portions 110a, 120a, and 130a, which are flexible members such as tubes, for example.

In this embodiment, the recording head 2 is configured to include a recording unit 113, and thus a wide range of recording operations can be realized at once. Additionally, the recording chips 100 constituting the recording unit 113 do not need to be physically coupled to each other as the recording head 2, and may be physically spaced apart.

The recovery unit 114 recovers the ink discharged from the recording unit 113. Recovery unit 114 includes a cap 114a and a suction pump 114b.

The cap 114a is a unit for receiving ink discharged from the recording unit 113. The cap 114a is configured to cover the recording unit 113. The shape of each cap 114a is a shape corresponding to the shape of the corresponding recording unit 113.

The suction pump 114b sucks ink from the recording unit 113 through the cap 114a. The suction pump 114b is installed on the ink flow path 117. The flow path 117 is formed between the cap 114a and the waste ink tank 140. The solenoid valve 116 will be described later.

<Ink Euro>

Figure 4 is a diagram for explaining the configuration of the ink flow path of the recording device 1. In this embodiment, the recording device 1 includes passages 110, 117, 118, and 119 as ink passages. Hereinafter, these may be collectively referred to as Euro FP. The flow path FP is formed of a flexible member such as a tube, for example.

The flow path 110 connects the main tank 101 containing ink and the recording head 2. In other words, the flow path 110 is a flow path for supplying ink to the recording head 2. On the flow path 110, an electromagnetic three-way valve 105, a pressure pump 102, a filter 103, a sub tank 111, and a negative pressure adjustment unit 112 are installed.

The electromagnetic three-way valve 105 is connected to flow path 118 in addition to flow path 110. The electromagnetic three-way valve 105 allows the ink flowing from the main tank 101 to flow further downstream of the flow path 110 and flows the ink flowing through the flow path 118 downstream of the electromagnetic three-way valve 105 of the flow path 110. It is configured to be switchable between the state of leaking to the side. In addition, in the state between these, the electromagnetic three-way valve 105 is in a state in which both the ink flowing from the main tank 101 and the ink flowing from the flow path 118 flow out to the downstream side of the electromagnetic three-way valve 105. It can also be

The pressure pump 102 supplies ink in the flow path downstream. The filter 103 removes minute foreign substances contained in the ink. The sub tank 111 temporarily stores ink ejected by the recording unit 113. The negative pressure adjustment unit 112 appropriately maintains the negative pressure provided to the nozzle 3 of the recording unit 113. Additionally, if the negative pressure of the nozzle 3 can be appropriately managed by a water head difference supply method or the like, the negative pressure adjustment unit 112 may be omitted.

The flow path 117 connects the cap 114a described above with the waste ink tank 140 that accommodates waste ink. In other words, the flow path 117 is a flow path for disposing of ink. On the flow path 117, the above-described suction pump 114b and solenoid valve 116 are installed. The solenoid valve 116 has an open state that allows ink flowing from the cap 114a side to flow out to the waste ink tank 140 side, and a closed state that regulates the outflow of ink to the waste ink tank 140 side. It is configured to be switchable between.

Flow path 118 connects the recording head 2 and the electromagnetic three-way valve 105. Additionally, on the flow path 118, electromagnetic three-way valves 106 and 107 are installed. The electromagnetic three-way valve 106 is configured to be switchable between a state in which ink flowing from the upstream side flows out to the downstream side of the flow path 118 (direction A) and a state in which it flows out to the flow path 119 side (direction B). there is. Additionally, a degassing unit not shown in the flow path 118 may be installed to degas the ink flowing into the flow path 110.

Flow path 119 connects the electromagnetic three-way valve 106 and electromagnetic three-way valve 107 through a separate path from flow path 118. In other words, Euro 119 diverges from Euro 118 and joins Euro 118 again. On the flow path 119, a detection unit 108 described later is installed.

In this embodiment, the ink that has passed through the recording head 2 is transferred back to the recording head 2 by a part of the flow path 110 (the part from the electromagnetic three-way valve 105 to the recording head 2), flow path 118, and flow path 119. Circulation flow path FP1 that circulates in (2) is constructed. Accordingly, the members forming the flow paths 110, 118, and 119 constitute a circulation flow path forming portion that forms the circulation flow path PF1.

In addition, in this embodiment, the circulation flow path F1 is a flow path 119 in which the detection unit 108 is installed and a bypass flow path that bypasses the detection unit 108 (a portion between the electromagnetic three-way valve 106 and the electromagnetic three-way valve 107 of the flow path 118). includes. And, by the electromagnetic three-way valve 106 and the electromagnetic three-way valve 107, between a circulation state in which the ink circulating in the circulation flow path FP1 passes only flow path 119 and a circulation state in which the ink circulating in the circulation flow path FP1 passes only the bypass flow path. It is configured to be convertible. Accordingly, ink can be prevented from passing through the detection unit 108 when detection by the detection unit 108 is not performed. In addition, a configuration in which all ink circulating in the circulation flow path FP1 passes through the detection unit 108 can be adopted without providing such a bypass flow path in the circulation flow path FP1.

Additionally, in this embodiment, by operating the solenoid valve 116 and the suction pump 114b in an appropriate combination, the ink discharged into the cap 114a can be discharged downstream. Additionally, the recording unit 113 included in the recording head 2 uses ink of the same type (same color), and when using ink of multiple types (multiple colors), multiple recording heads of the same configuration are prepared. It's good to do it. Hereinafter, the description will be made as if a single type (same color) of ink is used.

<Detection unit>

Figure 5 is a schematic diagram showing the configuration of the detection unit 108. The detection unit 108 optically detects the state of functionality regarding the emission of ink ejected from the recording head 2 (recording unit 113). The detection unit 108 includes a light irradiation unit 120, a measurement cell 121, and a light reception unit 122.

The irradiation unit 120 irradiates inspection light to the ink. In the case of this embodiment, the inspection light irradiated by the irradiation unit 120 is selected to have a wavelength that allows the light-emitting material of the irradiated ink to change color or emit light. The wavelength of the inspection light will be described later.

The measurement cell 121 is a cell in which a certain amount of ink to be inspected is filled. The ink filled in the measurement cell 121 changes color or emits light by receiving inspection light emitted from the irradiation unit 120.

The light receiving unit 122 receives light from the ink in the measurement cell 121 and detects its intensity. In this embodiment, the light receiving unit 122 splits the light from the ink in the measurement cell 121 for each wavelength and detects the intensity of the split light. As the light receiving unit 122, a known one can be used as appropriate. For example, as the light receiving unit 122, a general spectrophotometer may be used, or a combination of a band-pass filter and a general measuring instrument capable of measuring the intensity of light may be used. In addition, in the detection unit 108 illustrated in FIG. 5, the irradiation unit 120 and the light receiving unit 122 are arranged for transmission measurement, but the light receiving unit 122 is arranged in a direction orthogonal to the direction of the optical axis of the irradiation unit 120. You can do it. In other words, the detection unit 108 can detect the state of the functional ink.

In this embodiment, the state of the ink circulating in the circulation passage PF1 can be detected by the detection unit 108. Accordingly, it is possible to obtain information necessary for determining whether to discard ink or not, and based on this information, it is possible to suppress discarding unnecessary ink.

<Wavelength of inspection light>

As described above, in this embodiment, the state of the ink discharged from the recording unit 113 is detected by the detection unit 108. However, in the recording device 1, there are cases where an ultraviolet curing ink containing an ultraviolet curing initiator is used. Compared to thermosetting ink, ultraviolet curable ink can form a thicker layer with a single inkjet application. On the other hand, the ultraviolet curing initiator starts curing when it absorbs ultraviolet rays of a predetermined wavelength. Therefore, depending on the wavelength of the inspection light emitted by the irradiation unit 120 of the detection unit 108, there is a risk that the reaction of the ultraviolet curing initiator may proceed and the ink may thicken when the state of the ink is detected by the detection unit 108. .

Specifically, if the ink thickens due to the inspection light from the detection unit 108, the inspected ink must be discarded, resulting in a disposal cost. Additionally, there may be a case where the ink viscosity of the entire flow path increases due to the diffusion of the thickened ink, and a case may also occur where all the ink in the circulation flow path PF1 must be discarded. In other words, as a result of detecting the functionality of the ink by the detection unit 108 to determine whether or not to discard the ink, there is a risk that a case may occur where the ink thickens due to the inspection light and the ink needs to be discarded. there is.

Therefore, in this embodiment, the wavelength of the inspection light of the detection unit 108 is set to satisfy the relationship that the ultraviolet curing initiator does not substantially absorb light at the wavelength fx-ljmm obtained by subtracting the half width hlm from the peak wavelength fx of the inspection light. do. As shown in Figure 6, the peak wavelength fx is the wavelength at which the relative irradiation intensity of the inspection light is maximum. In addition, the half width hjm is the difference between the wavelength when the relative irradiation intensity is half the maximum intensity and the peak wavelength fj. In addition, in this embodiment, “the ultraviolet curing initiator does not substantially absorb light” is said to indicate that the ink containing the ultraviolet curing initiator does not thicken even when the ink is irradiated with inspection light for one hour. Additionally, as a specific wavelength of inspection light, the peak wavelength f may be set in the range of 450 nm to 490 nm. Accordingly, it is possible to avoid overlap between the photosensitive wavelength of the ultraviolet curing initiator generally used in ink and the inspection light.

According to the present embodiment, the overlap between the wavelength range of the inspection light and the photosensitive wavelength of the ultraviolet curing agent contained in the ink can be avoided, so thickening of the ink can be suppressed when detecting the state of the functionality of the ink by the detection unit 108. You can.

<Example of operation of recording device>

Next, an example of the operation of the recording device 1 will be described, mainly with reference to FIG. 4. Hereinafter, the ink charging operation and recovery operation will be sequentially described.

(ink charging operation)

First, CPU 301 commands recovery control unit 304 to perform ink filling processing. The recovery control unit 304, which has received the command, drives the pressure pump 102 to supply ink from the main tank 101 to the flow path 110. At this time, the electromagnetic three-way valve 105 causes ink flowing from the main tank 101 to flow further downstream of the flow path 110, thereby filling the flow path 110 with ink. At that time, minute foreign substances pass through the filter 103 and are filtered out. Additionally, at this time, the ink supplied from the main tank 101 may be appropriately degassed using a degassing unit, etc., not shown.

Additionally, by installing the sub tank 111 in the flow path 110, it becomes possible to replace the main tank 101 while continuing the recording operation with the recording unit 113 even when the main tank 101 is empty. . In addition, although ink filling using the pressurized method has been explained here, ink filling using a reduced pressure method such as suction from a cap is also possible.

(recovery action)

Next, an example of operation when recovery operation of the nozzle 3 of the recording head 2 is required will be described. An example of a case in which a recovery operation is necessary is when the recording head 2 is not used for a long period of time and thickening occurs near the nozzle due to volatilization of components in the ink. Alternatively, when the recording head 2 is continuously used for a recording operation, ink deposits or foreign substances adhere to the vicinity of the nozzle 3 of the recording head 2. In this case, it becomes necessary to perform a so-called light recovery operation such as flushing or wiping on the nozzle 3 of the recording head 2. On the other hand, as the thickening of the ink near the nozzle 3 or the adhesion of the mist to the nozzle 3 progresses, sufficient recovery is not expected in the light recovery operation as described above, so a so-called heavy recovery operation may be necessary. there is. Examples of the mid-recovery operation include pressure recovery operation. In other words, the vicinity of the nozzle 3 of the recording unit 113 is pressurized by appropriately operating the pressure pump 102 and the electromagnetic three-way valve 105 of the flow path 110, thereby pressurizing the area near the nozzle 3 of the recording unit 113 via the nozzle 3. Ink is discharged onto the cap 114a. Additionally, as another medium recovery operation, a suction recovery operation can be mentioned. In other words, the recording head 2 and the cap 114a are brought into contact to properly operate the suction pump 114b and the solenoid valve 116 to discharge ink from the nozzle 3 by suction.

However, in this embodiment, another method of suppressing thickening near the nozzle 3 is to circulate the ink without letting it remain near the nozzle 3. In other words, in this embodiment, the ink near the nozzle 3 of the recording head 2 is circulated through the circulation flow path FP1. On the other hand, even when the ink is circulated, it comes into contact with atmospheric air when passing through the vicinity of the nozzle 3 of the recording head 2, so the functional ink containing the above-described luminescent material is subject to deterioration. There is. If recording is performed using ink that has deteriorated, there is a risk that the recorded material may not exhibit the desired performance, so the ink that has deteriorated needs to be discarded. On the other hand, discarding ink that has not deteriorated enough to require disposal may lead to an increase in ink consumption. Therefore, in this embodiment, the discarding of unnecessary ink is suppressed by detecting the state of the circulating ink.

<Processing example>

(Disposal of ink)

Using Figures 4 and 7, a method for suppressing unnecessary waste of ink by detecting the state of the ink will be explained. Figure 7 is a flowchart showing an example of processing of CPU 301. This flowchart is realized, for example, by the CPU 301 reading the program stored in the RM 302 to the RM 312 and executing it. For example, this flowchart is executed at a predetermined cycle while the recording device 1 is in operation. Additionally, for example, this flowchart is executed based on the power of the recording device 1 being turned on.

In S1, CPU 301 performs ink status detection processing. CPU 301 commands detection control unit 314 to perform ink status detection processing. The detection control unit 314, which has received the command, detects by the detection unit 108 installed in the flow path 119. Additionally, CPU 301 controls the flow of ink so that ink passes through the detection unit 108 by changing the electromagnetic three-way valves 106 and 107 as needed.

In S2, CPU 301 executes standard judgment processing. Based on the result of the status detection process in S1, CPU 301 determines whether the standard for using ink for recording processing (hereinafter referred to as standard A) is met. For example, CPU 301 determines whether the state of functionality of the ink satisfies criterion A based on the degree of deterioration of the ink. CP301 can confirm the degree of deterioration based on the change in the detection result by the detection unit 108. Additionally, CPU 301 stores the luminous intensity of the ink at the initial stage of ink filling and can confirm the degree of ink deterioration based on the difference or ratio with the luminous intensity at the time of standard judgment processing. Additionally, the degree of ink deterioration can also be said to be the degree of decline in the functionality of the ink.

For example, to check the functionality of the color conversion function of the ink, the light emission intensity (the intensity of light detected by the light receiving unit 122) at the initial stage of ink filling in the wavelength matching the color after color conversion is set to 100%, and then Examine the degree of change from . CPU 301 may determine that the state of the ink does not meet the standard A when the ratio of the light emission intensity during the standard judgment process to the initial stage of ink filling is less than 99%. In the following description, the ratio of the light emission intensity during the standard judgment processing to the initial stage of ink filling may be referred to as an ink function value. In other words, criterion A may be an ink function value of 99% or more. However, this standard for the ink function value is an example and can be changed depending on which of the reduction of ink waste amount and maintenance of the ink function is given priority.

If it is a spectrophotometer, the value can be checked around the wavelength of 546 nm when converted to green, and around the wavelength of 640 nm when converted to red. By combining a band-pass filter and a general measuring instrument capable of measuring the intensity of light, the intensity of light emission in a range including the wavelengths of each color described above can be measured. Additionally, any method other than the above can be used as long as it is a general method that can measure the intensity or quantum efficiency of light after color conversion.

In S3, if the CPU 301 determines that the standard A is met in the standard judgment process of S2, the flowchart ends, and if not, the process proceeds to S4.

In S4, CPU 301 discards and refills ink. CPU 301 instructs circulation control unit 313 to discard and recharge ink from circulation flow path PF1. The circulation control unit 313, which has received the command, appropriately operates the cap 114a, the suction pump 114b, and the solenoid valve 116 to transfer the ink circulating through the nozzle 3 through the circulation passage PF1 to the waste ink tank 140. ) is discharged to. After that, the circulation control unit 313 appropriately operates the electromagnetic three-way valve 105 and the pressure pump 102 to fill the circulation flow path PF1 with ink. In addition, the discarding of ink may be discarding almost the entire amount of ink flowing through the circulation flow path FP1, or may be discarding a predetermined amount (or a predetermined ratio) of ink flowing through the circulation flow path FP1.

According to the processing example described above, whether or not to discard ink is determined depending on the detection result of the detection unit 108, so discarding of unnecessary ink can be suppressed.

Additionally, regarding discarding ink, when the detection unit 108 detects that there is a specific location in the circulation passage where deterioration is particularly progressing, control may be performed to discard a large amount of ink only at the location where deterioration has progressed. . CPU 301 may monitor the detection result of detection unit 108 for a predetermined period to identify a location where ink deterioration has progressed locally. The predetermined period may be, for example, a period in which the ink in the circulation flow passage FF1 travels around the flow passage for one time. By discarding only the areas where ink is deteriorating, the amount of ink wasted can be suppressed. Additionally, in order to effectively dispose of areas where ink is deteriorating, a flow path for discarding ink may be connected near the downstream side of the detection unit 108.

(Processing to restore functionality of ink)

Figure 8 is a flowchart showing an example of processing of CPU 301. In the example of Fig. 7, an example of discarding ink when the ink no longer meets the standards for use in recording processing has been explained. Here, a process for restoring the functionality of the ink at a stage where ink deterioration has progressed to a certain degree before the ink no longer meets the standards for use in recording processing will be described.

S11 and S12 are the same processes as S1 and S2 in FIG. 7. However, in S12, CPU 301 determines whether the state of the ink satisfies standard B in addition to the above-mentioned standard A. Standard B is a standard for confirming that a certain degree of deterioration is progressing, for example, when the state of the ink satisfies the standard for use in recording processing (standard A). As an example, standard A may be set as an ink function value of 99% or more, and standard B may be set as an ink function value of 99.5% or more.

In S13, if the CPU 301 determines that the standard A is met through the standard judgment process in S12, the process proceeds to S14, and if not, the process proceeds to S16. S16 has the same processing as S4.

In S14, if the CPU 301 determines that the standard B is satisfied through the standard judgment process in S12, the flowchart ends, and if not, the process proceeds to S15.

In S15, CPU 301 performs ink functionality restoration processing. This treatment is intended to restore the functionality of the ink before the ink deteriorates to the extent that it needs to be discarded, and to prolong the usable period of the ink circulating in the circulation flow path F1. For example, CPU 301 may properly operate the pressure pump 102 and the electromagnetic three-way valve 105 to supply new ink from the main tank 101 to the circulation flow path PF1. Alternatively, a part of the ink circulating in the circulation flow path PF1 may be discarded due to a decrease in the amount of ink held in the sub tank 111, etc. By reducing the total amount of ink circulating in the circulation flow path PF1, the circulating ink can be consumed as quickly as possible, contributing to extending the usable period of the ink. Additionally, both supply of new ink and disposal of part of the ink may be performed.

Additionally, when the ink is heated with a heater (not shown) only in the vicinity of the recording head 2 to adjust the viscosity of the ink, the ink heating temperature may be lowered as a functionality recovery process. Accordingly, since deterioration of the ink due to heat can be suppressed, the period during which the ink circulating in the circulation flow path PF1 can be used can be extended. Additionally, when lowering the heating temperature, the nozzle 3 needs to eject ink with a high viscosity, so the ejection conditions of the nozzle 3 of the recording head 2 may be appropriately changed.

(Ink amount correction processing)

Figure 9 is a flowchart showing an example of processing of CPU 301. If recording processing is performed while the luminescent function of the luminescent material contained in the ink is deteriorated, the luminescent performance of the result of the recording process (for example, an organic light-emitting layer or a quantum dot color conversion layer) deteriorates. On the other hand, even if the light-emitting function of the light-emitting material deteriorates, the light-emitting performance of the result can be maintained by increasing the amount of ink provided accordingly. Here, a process for correcting the amount of ink provided in the recording process when ink deterioration has progressed to a certain degree will be explained.

S21 and S22 are the same processes as S11 and S12 in FIG. 8. However, in S22, CPU 301 also determines whether the state of the ink satisfies criteria A1 and criteria C. Standard A1, like standard A, is a standard for using ink for recording processing, but may be set to a lower standard value than standard A, for example. Additionally, standard C is a standard for increasing the amount of ink provided in order to maintain the luminous performance of the result of recording processing. For example, standard A1 may be set as an ink function value of 98% or more, and standard B may be set as an ink function value of 99% or more.

In S23, if the CPU 301 determines that the standard A1 is met through the standard judgment process in S22, the process proceeds to S24, and if not, the process proceeds to S26. S26 has the same processing as S4.

In S24, if the CPU 301 determines that the standard C is met through the standard judgment process in S22, the flowchart ends, and if not, the process proceeds to S25.

In S25, CPU 301 performs ink application amount correction. For example, CPU 301 may correct the amount of ink applied so that the greater the degree of decrease in the luminous intensity of ink at the time of state detection, the greater the increase in the amount of ink applied. More specifically, the CPU 301 may correct the amount of ink applied to compensate for the decrease in functionality related to light emission in a recording object such as the substrate 11 to which ink is applied. In other words, if the light-emitting function of the light-emitting material is deteriorating, the deterioration of the function of the result of the recording process (e.g., organic light-emitting layer or quantum dot color conversion layer) can be suppressed by increasing the amount of light-emitting material applied. You can.

According to this processing example, the ink can be used for recording processing even when the ink has deteriorated to a certain degree, so the amount of ink wasted can be reduced.

<Example>

Hereinafter, the present invention will be described in more detail by giving examples, but the present invention is not limited to these examples.

(Example 1)

Recording processing was performed using the recording device 1 according to the above embodiment. The ink was heated at 40°C with a heater (not shown) only in the vicinity of the recording head 2 to adjust the viscosity. The standard for the ink function value (corresponding to standard A in the above embodiment) was set at 99%, and if it was lower than 99%, all ink in the circulation flow path PF1 was discarded. The process for disposing of ink follows the flowchart in FIG. 7 of the above-described embodiment. The amount of waste per time in this case was 100g.

In this example, INP/ZNS core-shell type quantum dot 776750 (production number of Sigma-Aldrich Japan Limited) was used as the quantum dot material. In addition, blue LED NCSB119T (model number of Nichia Chemical Industry Co., Ltd.) was used as an irradiation light (inspection light). In addition, as an ultraviolet curing initiator, Omjrd 907 (brand name of IGM LBB) was used.

In Figure 10, the relative irradiation intensity of blue LED is shown by the broken line, and the molar extinction coefficient of the ultraviolet curing initiator (OmniRd 907) is shown by the solid line. The wavelength obtained by subtracting the half maximum width from the wavelength peak value of the blue LED is indicated by a dashed line. As can be seen from the fact that the molar extinction coefficient of OmniRd 907 is less than 0.2% of the peak at this wavelength, it can be said to be an ultraviolet curing initiator that does not have an absorption characteristic in the wavelength range of the inspection light. By using such an ultraviolet curing initiator, it was possible to determine the quantum dot ink deterioration state using the detection unit 108 while maintaining a state in which no curing reaction occurred. In other words, in this embodiment, by using such an ultraviolet curing initiator, the state of the functionality of the ink can be continuously checked by the detection unit 108 without causing waste of the ink due to inspection by the detection unit 108. I was able to. In other words, in this example, by setting the wavelength range of the inspection light to avoid overlap with the absorption wavelength of the ultraviolet curing agent expected to be used, it was possible to maintain a state in which no curing reaction occurred.

(Example 2)

Hereinafter, differences from Example 1 will be explained. This example is Example 1, except that the ultraviolet curing initiator contained in the ink is Omijd 184 (trade name of IGO Co., Ltd.) instead of Omjrd 907. Same as

Even in the case of this combination, as shown in Figure 10, since the irradiation wavelength of the inspection light and the absorption wavelength of the ultraviolet curing initiator do not overlap, by using this ultraviolet curing initiator, as in Example 1, no curing reaction occurred. It was possible to determine the deterioration state of the quantum dot ink while maintaining its condition.

(Example 3)

Hereinafter, differences from Example 1 will be explained. In this embodiment, after the ink function value fell below 99.3%, control was performed to reduce the amount of ink held in the sub tank 111 to reduce the amount of waste when the entire ink was discarded. In other words, in the flowchart of FIG. 8 of the above embodiment, the reference A is set to an ink function value of 99% and the reference B is set to an ink function value of 99.3%, and as a functionality recovery process, the amount of ink held in the sub tank 111 is reduced. was done. Accordingly, the amount of ink wasted when the ink function value fell below 99% was 90g. In other words, the functionality of the ink deteriorated, and the amount of waste when discarding all of the ink circulating in the entire circulation flow path PF1 was able to be reduced. In other words, by controlling the amount of ink held in the sub tank 111, which is an example of a parameter related to the circulation of ink, it was possible to reduce the amount of waste when discarding all of the ink.

(Example 4)

Hereinafter, differences from Example 1 will be explained. In this embodiment, when the ink function value falls below 99.5%, the electromagnetic three-way valve 105 is controlled to supply 10 g of new ink and discard 10 g of ink to the waste ink tank 140. . In other words, in the flowchart of FIG. 8 of the above embodiment, the reference A is set to an ink function value of 99%, and the reference B is set to an ink function value of 99.5%, and as a functionality recovery process, a portion of the ink in the circulation flow path FP1 is disposed of. did it In this case, the ink function value recovered to 99.8%. In other words, using this method, it was possible to restore the functionality of the entire ink circulating in the circulation flow path PF1. As a result, it was possible to suppress the total waste of ink circulating in the circulation flow path PF1, and reduce the total amount of ink wasted when viewed as a whole. In addition, the amount of ink wasted from the circulation flow path PF1 and the amount of ink supplied to the circulation flow path PF1 are examples of parameters related to the circulation of ink, and by controlling these parameters, the functionality of the ink circulating in the circulation flow path PF1 can be restored. I was able to.

(Example 5)

Hereinafter, differences from Example 1 will be explained. In this example, when the value of the detected ink function was 98% or more but less than 99%, control was performed to increase the amount of ink applied to the substrate according to a preset correction table. In other words, in the flowchart of Fig. 9 of the above embodiment, reference A1 is set to an ink function value of 98%, and reference C is set to an ink function value of 99%. Accordingly, it became possible to lower the standard A1 of the ink function value to 98%. Additionally, an example of a correction table for the amount of ink applied to each nozzle 3 is given below.

In addition, although a form in which the ink application amount is corrected using a correction table is exemplified here, a form in which the ink application amount is corrected according to the following equation, for example, when ink is ejected is also applicable.

Amount of ink applied after correction (pl) = Amount of ink applied before correction (pl) × (1/ink function value (%)) (1)

(Example 6)

Hereinafter, differences from Example 1 will be explained. In this example, the circulation flow path F1 was divided into three sections along the length of the ink flow path, and the ink function at each location was tested. In cases where the functional value of some ink was deteriorating by more than 0.3% compared to other parts, the deteriorated ink was circulated to the head and pressure-discarded as an example of functionality recovery treatment. As a result, it was confirmed that the overall average value of the ink function recovered by 0.1%.

(Comparative Example 1)

Hereinafter, differences from Example 1 will be explained. This comparative example is the same as Example 1 except that the detection unit 108 is not provided. The ink function value was determined by measuring the luminous efficiency after applying ink to a glass substrate, curing it, manufacturing a display device in which various components were bonded together.

As a result of continued use for a certain period of time, the display has fallen below the standards for ink function values. The cost of manufacturing a display that fell below the standard for ink function value was equivalent to 500g of ink.

(Comparative Example 2)

Hereinafter, differences from Example 1 will be explained. In this comparative example, all examples are examples except that the ultraviolet curing initiator contained in the ink is not Ｏｍｍｎｉｒａｄ 907 but Ｏｍｍｎｉｒａｄ 369 (trade name of ＩＧＭ Ｌｅｓｉｎｓ Ｂ：０． company) Same as 1.

In this combination, as shown in Figure 10, the irradiation wavelength of the inspection light and the absorption wavelength of the ultraviolet curing initiator overlap. Accordingly, when irradiated with inspection light, the ink underwent an ultraviolet curing reaction and thickened. The tested ink could not be used continuously, resulting in ink disposal costs.

(Comparative Example 3)

Hereinafter, only the differences from Example 1 will be explained. In this comparative example, the ultraviolet curing initiator contained in the ink is not Ｏｍｍｎｉｒａｄ 907 but Ｏｍｎｎｒｒａ ＴＰＯ H (trade name of ＩＧＭ Ｌｅｓｉｎｓ Ｂ．Ｖ． company) Everything else was the same as Example 1.

In this combination, as shown in Figure 10, the irradiation wavelength of the inspection light and the absorption wavelength of the ultraviolet curing initiator overlap. Accordingly, when irradiated with inspection light, the ink underwent an ultraviolet curing reaction and thickened. The tested ink could not be used continuously, resulting in ink disposal costs.

As described above, by determining the deterioration state of the quantum dot ink while maintaining the state of no ultraviolet curing reaction, ink is not discarded unnecessarily, and ink that is guaranteed that the degree of deterioration of the functional ink is below a certain level is used. It becomes possible to do so.

The present invention provides a program that realizes one or more functions of the above-described embodiments to a system or device through a network or storage medium, and one or more processors in a computer of the system or device reads and executes the program. It is also feasible in processing. In addition, it can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

The invention is not limited to the above embodiments, and various changes and modifications are possible without departing from the spirit and scope of the invention. Therefore, the claims are attached to clarify the scope of the invention.

1: recording device, 2: recording head, 108: detection unit, ５Ｐ1: circulation flow path

Claims (15)

a recording head that performs recording by discharging a liquid containing a light-emitting material;
A recording device comprising detection means for optically detecting a state of functionality related to light emission of the liquid.
According to claim 1,
A recording device characterized in that the detection means includes an irradiation unit that irradiates inspection light to a liquid, and a light reception unit that receives light from the liquid to which the inspection light has been irradiated.
According to claim 2,
the liquid contains an ultraviolet curing initiator,
A recording device wherein the ultraviolet curing initiator does not substantially absorb light at a wavelength obtained by subtracting the half maximum width from the peak wavelength of the inspection light.
According to claim 2,
A recording device, wherein the inspection light has a peak wavelength of 450 nm to 490 nm.
According to claim 1,
The recording device further comprising correction means for correcting the amount of liquid applied by the recording head based on the condition.
According to claim 5,
A recording apparatus, characterized in that the correction means corrects the application amount so as to compensate for a decrease in functionality related to light emission in a recording object to which the liquid is applied.
According to claim 1,
A recording device characterized by further comprising parameter control means for controlling parameters related to the circulation of liquid based on the above state.
According to claim 1,
a circulation flow path forming portion that forms a circulation flow path for circulating the liquid that has passed through the recording head back to the recording head;
A recording device characterized in that the detection means optically detects a state of functionality related to light emission of a liquid circulating in the circulation passage.
According to claim 8,
A recording device characterized by further comprising disposal means for discarding liquid from the circulation passage based on the condition.
According to claim 8,
The recording device according to claim 1 , further comprising processing means for executing processing to restore functionality related to light emission of the liquid circulating in the circulation passage, based on the state.
According to claim 8,
a first liquid reservoir provided outside the circulation flow path;
a second liquid reservoir installed in the circulation flow path;
The recording device further comprising adjustment means for adjusting the amount of liquid stored in the second liquid storage portion based on the state.
According to claim 8,
A recording device characterized by further comprising supply means for supplying liquid to the circulation passage based on the condition.
According to claim 8,
A recording device characterized in that the detection means is installed on the circulation passage.
According to claim 13,
The circulation flow path includes a first flow path in which the detection means is installed, and a second flow path that bypasses the detection means,
The recording device has a first circulation state in which the liquid circulating in the circulation passage passes through the first passage, a second circulation state in which the liquid circulating in the circulation passage passes only the second passage, and A recording device, characterized in that it further comprises a switching means switchable between.
The method according to any one of claims 1 to 14,
A recording device, wherein the recording head discharges the liquid used for the quantum dot color conversion layer to the substrate.

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