Patent Application
20250050642
The present disclosure relates to a liquid discharge apparatus, and a method for cleaning a discharge port face of the liquid discharge apparatus.
An ink-jet recording apparatus, a type of a liquid discharge apparatus, records images and texts on a recording medium by discharging a liquid from substrates having a discharge port face provided with a discharge port for discharging a liquid. If ink coagulations, dirt in the apparatus, dusts, or paper dusts from a recording medium adhere to the ink discharge port face, defective printing may possibly occur. Therefore, conventional ink-jet recording apparatuses use a cleaning method for wiping the discharge port face to wipe out adhering substances by using a wiping member during non-print time. During this cleaning, members around the ink discharge port face that may be subject to ink adhesion are generally wiped at the same time. However, members susceptible to scraping may possibly generate dirt due to abrasion. In particular, an ink-jet recording apparatus is provided with a member having a recessed portion for storing the substrate. The surface of a sealing material for sealing the gap between the recessed portion and the substrate is likely to be inclined by the difference in wettability from peripheral members in contact and the hardening and shrinkage of the sealing material itself. Therefore, if the wiping member ununiformly comes into contact with the sealing material, the wiping member scrapes the sealing material by the abrasion, possibly generating dirt.
Japanese Patent Application Laid-Open No. 2014-159118 discloses a method for restricting the abrasion of a sealing material by reducing the friction between a wiping member and a sealing material. With this method, the wiping member is soaked with a silicone oil component, and the bled out oil component is applied from the wiping member to the sealing material.
With this method, however, silicone oil may adhere to the discharge port face while the discharge port face is being wiped. This is because the wiping member for wiping the discharge port face and the oil application member soaked with silicone oil are the same member. As a result, a liquid is not normally discharged, possibly resulting in defective printing.
In view of the above-described issue, the present disclosure is directed to providing a liquid discharge apparatus for preventing defective printing while reducing the abrasion of a sealing material by a wiping member, and a method for cleaning a discharge port face of the liquid discharge apparatus.
According to an aspect of the present disclosure, a liquid discharge apparatus includes a substrate having a discharge port face provided with a discharge port for discharging a liquid, a member having a recessed portion for storing the substrate, a sealing material for sealing a gap between the recessed portion of the member and the substrate, a wiping member configured to wipe the discharge port face, and an application member configured to apply oil to the sealing material.
Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings. The following exemplary embodiments do not limit the present disclosure. Not all of the combinations of the features described in the exemplary embodiments are indispensable to the solutions for the present disclosure. In the following drawings, identical components are assigned the same reference numerals.
According to the present disclosure, unless otherwise specified, a numerical range description or a description “XX to YY” means a numerical range including end points, i.e., upper and lower limits. If a numerical range is described in a stepwise way, the upper and lower limits of each numerical range can be optionally combined.
Firstly, the liquid discharge head 3 according to the present disclosure will be described below.
As described above, the substrate 2 includes the discharge port face 13 for discharging a liquid. Ink coagulations, dirt in the liquid discharge apparatus, dust, or paper dust from a recording medium may adhere to the discharge port face 13. Cleaning the discharge port face 13 is effective to remove these substances.
A cleaning method according to the present exemplary embodiment will be described below.
The liquid discharge apparatus according to the present exemplary embodiment includes the application member 22 for applying oil to the sealing material 8, a first oil supply unit 7 for supplying oil to the application member 22, and an oil storage unit (not illustrated) for storing oil. Firstly, the application member 22 is moved in the A direction in
The first oil supply unit 7 may be disposed on the liquid discharge head 3.
Then, when the application member 22 further moves in the direction of the arrow A, and the application member 22 and the sealing material 8 come into contact with each other, oil is supplied from the application member 22 to the sealing material 8 (first application process or process b). In this process, advantageously, the application member 22 does not apply oil to the discharge port face 13. This enables preventing defective printing caused by oil adhering to the discharge port face 13. Therefore, advantageously, the application member 22 is configured to come into contact only with the sealing material 8 around the substrate 2 as illustrated in
Preferably, in addition to the first oil supply unit 7, the liquid discharge apparatus 1 includes a second oil supply unit 17 for supplying oil to the application members 22 after the first application process, as illustrated in
A process of cleaning the discharge port face 13 by using the wiping member 21 will be described below. As illustrated in
When the wiping member 21 further moves in the A direction, the wiping member 21 separates from the discharge port face 13 (process e). Advantageously, the liquid discharge apparatus 1 includes a cleaner 4 for removing dirt adhering to the wiping member 21. If the liquid discharge apparatus 1 includes the cleaner 4, the wiping member 21 further moves in the A direction to come into contact with the cleaner 4. Then, dirt adhering to the wiping member 21 are removed (process f). Advantageously, when the wiring member 21 comes into contact with the cleaner 4 and then moves in the B direction, the wiping member 21 wipes the discharge port face 13. The cleaner 4 may be anything as long as it can remove dirt adhering to the wiping member 21. For example, the cleaner 4 may be a cloth for wiping the wiping member 21.
As described above, by employing separate members for the application member 22 for applying oil to the sealing material 8 and the wiping member 21 for wiping the discharge port face 13, it becomes possible to prevent defective printing due to the oil adhesion to the discharge port face 13 while reducing the abrasion of the sealing material 8 by the application member 22.
The oil according to the present exemplary embodiment will be described below. The oil according to the present exemplary embodiment reduces the friction coefficient between the wiping member 21 and the sealing material 8. Advantageously, the oil is an oily resin made of straight-chain polymer. More specifically, silicone-based oils, polyglycol-based oils, and ester-based oils are desirable.
Silicone-based oils according to the present exemplary embodiment refer to oily resins having a siloxane bond as the main frame. Specific examples of silicone-based oils include dimethyl silicone oils, and denatured silicone oils in which various organic groups are introduced to a part of methyl groups in molecules, such as alkyl denatured silicone oil, fluorine denatured silicone oil, polyether denatured silicone oil, alcohol denatured silicone oil, amino denatured silicone oil, epoxy denatured silicone oil, epoxy polyether denatured silicone oil, phenol denatured silicone oil, carboxy denatured silicone oil, mercapto denatured silicone oil, amide denatured silicone oil, carbana denatured silicone oil, and higher fatty acid denatured silicone oil. Specific examples of silicone oils include KF-96-10CS, KF-96-300CS (Shin-Etsu Chemical Co., Ltd.) and DOWSIL BY 16-846 Fluid (Dow Toray Co., Ltd.).
Polyglycol-based oils according to the present disclosure refer to polyalkylene glycol. Specific examples of polyglycol-based oils include PEG400, PEG600 and PEG1000 (SANYO CHEMICAL INDUSTRIES, LTD.).
Examples of ester-based oils according to the present disclosure include polyol ester oil, complex ester oil, and polyol carbonate ester oil. Examples of desirable polyol ester oils include esters of hindered alcohols. Examples of esters include trimethylol propane tripelargonate, pentaerythritol 2-ethyl hexanoate, and pentaerythritol tetrapelargonate. Examples of hindered alcohols include neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, and pentaerythritol. Examples of applicable products include the Uni-star M series and H series (NOF CORPORATION).
In particular, the use of silicone oil or polyglycol oil is desirable. Silicone-based and polyglycol-based oils can be advantageously used due to the high affinity with the wiping member 21 (described below) achieving lower friction.
Advantageously, the weight-average molecular weight of oil is 1,000 or more and 100,000 or less. If the weight-average molecular weight is within this range, oil is hardly volatilized and maintains fluidity, making it possible to effectively exhibit low abrasion. One type of oil, or a combination of two or more types of oil may be used.
The wiping member 21 and the application member 22 will be described below. The rubber hardness of the wiping member 21 according to the present exemplary embodiment is preferably 30 degrees and is more preferably 40 degrees or less according to Japanese Industrial Standard (JIS) so that the wiping member 21 can efficiently clean the discharge port face 13. From the viewpoint of reducing the possibility that the sealing material 8 is worn while the wiping member 21 is in contact with the sealing material 8, the rubber hardness of the wiping member 21 is preferably 80 degrees or less and is more preferably 70 degrees or less according to JIS. Also, to reduce the possibility that the sealing material 8 is worn while the application member 22 is supplying oil to the sealing material 8, the rubber hardness of the application member 22 is preferably 80 degrees or less and is more preferably 70 degrees or less according to JIS.
Since the application member 22 according to the present exemplary embodiment is intended to apply oil to the sealing material 8, advantageously, oil is easily delivered from the oil supply unit and is easy to be retained. Therefore, the contact angle of oil with respect to the application member 22 is advantageously 60 degrees or less and is more advantageously 40 degrees or less. On the other hand, advantageously, oil does not adhere to the wiping member 21. Therefore, advantageously, the contact angle of oil with respect to the wiping member 21 is 50 degrees or more. The contact angle of oil according to the present exemplary embodiment refers to the dynamic receding contact angle of oil.
Examples of applicable materials of the wiping member 21 and the application member 22 include ether-based urethanes, butyl rubber-based hydrogenated nitrile rubbers, and polypropylene. More desirable materials include ether-based urethanes and butylene rubber-based hydrogenated nitrile rubbers because these materials are not denatured by the oil adhesion and less likely to leave scratch marks on the sealing material 8. Particularly from the viewpoint of wettability, a material containing butyl rubber-based hydrogenated nitrile rubbers is suitably used. Advantageously, the material contains an ether-based urethane or a butyl rubber-based hydrogenated nitrile rubber. Particularly from the viewpoint of wettability, it is more desirable that the material contains a butyl rubber-based hydrogenated nitrile rubber.
The sealing material 8 according to the present exemplary embodiment will be described below. Advantageously, the sealing material 8 is likely to retain oil applied from the application member 22. More specifically, it is desirable that the contact angle of oil with respect to the sealing material 8 is 55 degrees or less.
Further, advantageously, the sealing material 8 easily receives oil from the application member 22. More specifically, it is desirable that oil is easily delivered to the sealing material 8 than to the application member 22. This allows oil to be efficiently delivered from the application member 22 to the sealing material 8, reducing the possibility that the sealing material 8 is worn by the wiping member 21. More specifically, it is desirable that the contact angle of oil with respect to the sealing material 8 is at least 10 degrees smaller than the contact angle of oil with respect to the application member 22.
Likewise, advantageously, the wiping member 21 is less likely to receive oil from the sealing material 8. More specifically, it is desirable that the sealing material 8 is more likely to retain oil than the wiping member 21. Further, it is desirable that the contact angle of oil with respect to the sealing material 8 is at least 10 degrees smaller than the contact angle of oil with respect to the wiping member 21.
From the viewpoint of the sealing performance, formability, and productivity, it is desirable that the sealing material 8 according to the present exemplary embodiment contains an epoxy resin composition. Particularly from the viewpoint of the adhesiveness of the sealing material 8 to the substrates 2 and the member 12, it is more desirable that the sealing material 8 contains an anion polymerization-based epoxy resin composition.
The sealing material 8 containing a silica filler in its composition enables improving the wettability and the low friction property due to the surface unevenness of the sealing material 8. The type of the silica filler is not particularly limited. From the viewpoint of preventing the increase in viscosity of the sealing material 8, it is desirable that the particle diameter is 0.1 μm or more and 100 μm or less. The particle diameter indicates a volume cumulative particle diameter D50 measured by a laser diffraction scattering particle size distribution measuring apparatus. From the viewpoint of improving the affinity with other materials, the use of a silane-treated silica filler is desirable. Advantageously, the composition of the sealing material 8 contains the silica filler by 40% by weight or more. As described above, to tightly fill the gap with the filler, it is desirable that the epoxy resin is in a liquid state at room temperature. Specific examples of epoxy resins include the hydrogenated epoxy resin series jERYX8000, YX8000D, YX8034, and YX8040 (Mitsubishi Chemical Group Corporation).
To improve compatibility between the filler and the epoxy resin, it is desirable to add a silane agent to the sealing material 8. In particular, the use of a silane agent with a low molecular weight is desirable. More specifically, the molecular weight of the silane agent is desirably 500 or less and is more desirably 300 or less.
Examples related to the wiping member 21, the application member 22, oil, and the sealing material 8, which are characteristic configurations according to the present exemplary embodiment, will be described below. The following materials are used as the components described by product names in the following examples and comparative examples.
The examples will be described below centering only on characteristic configurations and their operations in an example where the first oil supply unit 7 is disposed outside the liquid discharge head 3. We performed the cleaning method illustrated in the flowchart in
As illustrated in
Finally, as illustrated in
To evaluate the cleaning of the discharge port face 13 of the liquid discharge head 3, we repeated the above-described series of operations 1,500 times, and then observed a damage on the sealing material 8 and the ink adhesion to the discharge port face 13 by using an optical microscope. The following evaluation criteria were used:
Then, we evaluated the liquid discharge head 3 after the cleaning. We evaluated the print quality by visually observing streaks, white spots, and defective liquid jet in a 5% chart solid portion. Print patterns were printed with the 100% duty ratio for each ink in a chart with the 5% print area for each color out of the entire paper area. Print conditions include a recording density of 1,200 dots per inch (dpi) and one-pass printing.
According to a first comparative example, we performed only the wiping process for wiping the sealing material 8 by using the wiping member 21 without performing the oil application process for the sealing material 8. Other conditions were similar to those according to the first to the twentieth exemplary embodiments.
Evaluation results of the exemplary embodiments and comparative examples are illustrated in Tables 2 to 4.
According to the first to the twentieth examples, high print quality was obtained because the application member 22 for applying oil to the sealing material 8 and the wiping member 21 for wiping the discharge port face 13 were different members.
On the other hand, according to the first comparative example, the oil application process for the sealing material 8 was not performed, and hence the sealing material 8 was entirely damaged during the wiping of the discharge port face 13 of the wiping member 21. As a result, the print quality largely decreased.
As described above, by employing separate members for the application member 22 for applying oil to the sealing material 8 and the wiping member 21 for wiping the discharge port face 13, it becomes possible to prevent defective printing while reducing the abrasion of the sealing material 8 by the wiping member 21.
The present disclosure is directed to providing a liquid discharge apparatus capable of preventing defective printing while reducing the abrasion of a sealing material by a wiping member, and a method for cleaning a discharge port face of the liquid discharge apparatus.
While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Applications No. 2023-130033, filed Aug. 9, 2023, and No. 2024-083430, filed May 22, 2024, which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-130033 | Aug 2023 | JP | national |
| 2024-083430 | May 2024 | JP | national |
