JP2019209680A - Wiping member, wiping method and wiping equipment - Google Patents

Abstract

To solve such a problem that it is difficult to simultaneously efficiently carry out removal of a liquid fastening material in a nozzle formation face and absorption of excess liquid in that face in a wiping member wiping the nozzle formation face of a liquid discharge head discharging a liquid.SOLUTION: There is provided a wiping member for wiping the nozzle formation face of a liquid discharge head in which the wiping member satisfies P1<P2<P3, and P2/P1 is 1.1 or more but 1.4 or less when defining a thickness of the wiping member in a vertical direction of the surface contacting the nozzle formation face of the wiping member as t, the average porosity of a first area being the area in which the distance from a surface of the member in the vertical direction is 0 to t/3 as P1, the average porosity of a second area being the area in which the above distance is t/3 to 2t/3 as P2, and that porosity of a third area being the area in which that distance is 2t/3 to t as P3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wiping member, a wiping method, and a wiping device.

  A liquid discharge head in a liquid discharge apparatus typified by an ink jet printer may cause problems such as discharge failure due to foreign matters on the nozzle formation surface. For example, when the liquid is not discharged for a long time or when a highly dry liquid is discharged, the liquid thickens in the liquid flow path near the discharge port and normal discharge is not performed. There is.

  In order to cope with such ejection failure, the liquid ejection apparatus caps the ejection port surface of the recording head to prevent liquid thickening when ejection is not performed, and sucks liquid from the ejection port in this capped state. The liquid is discharged by a liquid suction process that discharges the thickened liquid, and an empty discharge process that discharges the liquid that has been thickened by discharging the liquid to a liquid receiver that has a liquid absorber in the same way as during normal discharge. There is a known method of returning to good conditions. A cleaning method is also known in which a sheet-like wiping member typified by a nonwoven fabric or a woven fabric is brought into contact with the nozzle forming surface of the liquid discharge head and moved relatively.

  Patent Document 1 discloses a wiping aiming to secure an absorption capacity of a wiping member that absorbs liquid adhering to the nozzle surface while suppressing bubble intrusion into the nozzle when the nozzle surface is wiped by a wiping member. A member is disclosed. Specifically, one surface is in contact with a nozzle surface on which nozzles for discharging droplets are formed, and there are a plurality of gaps that form capillaries from one surface side to the other surface side. A wiping member having a larger gap located on the other surface side than a gap located on the side, wherein the wiping member is formed by weaving a yarn bundle formed by bundling yarns, and the yarn bundle on the other side is one side There is disclosed a wiping member that is bundled more densely than the yarn bundle on the surface side, and that the gap between the yarn bundles is larger on the other surface side than on the one surface side.

  However, there is a problem that it is difficult to efficiently and simultaneously remove the liquid adhering matter on the nozzle forming surface and absorb the excess liquid on the nozzle forming surface.

  The invention according to claim 1 is a wiping member for wiping the nozzle forming surface of the liquid discharge head, wherein the thickness of the wiping member in the direction perpendicular to the surface of the wiping member that contacts the nozzle forming surface is t, An average porosity of a first region that is a region from 0 to t / 3 in the vertical direction is P1, and a second region that is a region from t / 3 to 2t / 3 Where P2 is the average porosity of the third region, and the average porosity of the third region, where the distance is 2t / 3 to t, is P3, P1 <P2 <P3 is satisfied, and P2 / P1 is 1 It is a wiping member which is 1 or more and 1.4 or less.

  The wiping member of the present invention has an excellent effect of efficiently and simultaneously removing the liquid adhering matter on the nozzle forming surface and absorbing excess liquid on the nozzle forming surface.

FIG. 1 is a diagram schematically illustrating an example of a cross section of a sheet-like wiping member. FIG. 2 is a diagram schematically illustrating an example of an image forming apparatus incorporating the wiping device. FIG. 3 is a diagram schematically illustrating an example of the nozzle formation surface of the liquid ejection head. FIG. 4 is a diagram schematically illustrating an example of the wiping device.

  Hereinafter, embodiments of the present invention will be described.

<< wiping member >>
The wiping member of this embodiment is a wiping member that wipes the nozzle formation surface by contacting the nozzle formation surface of the liquid ejection head that ejects liquid from the nozzles. In the present embodiment, “wiping” indicates that the wiping member and the liquid ejection head are relatively moved while the wiping member and the nozzle forming surface are in contact with each other. By wiping the nozzle forming surface using the wiping member of this embodiment, for example, liquid adhering matters such as cap marks generated by capping the nozzle forming surface for a long time can be removed from the nozzle forming surface. Further, for example, it is possible to remove from the nozzle forming surface by absorbing surplus liquid such as liquid overflowing from the nozzle caused by idle ejection.

  First, the wiping member will be described with reference to FIG. FIG. 1 is a diagram schematically showing an example of a cross section of a sheet-like wiping member. The wiping member shown in FIG. 1 is a single-layer nonwoven fabric, and has a surface that contacts the nozzle formation surface to wipe the nozzle formation surface of the liquid ejection head and a back surface that does not contact the nozzle formation surface. Moreover, in the wiping member of this embodiment, as shown in FIG. 1, the thickness of the wiping member in the direction perpendicular to the surface in contact with the nozzle forming surface is t. Further, a region where the distance from the surface in the vertical direction of the surface in contact with the nozzle forming surface is 0 to t / 3 is defined as a first region, and the distance from the surface in the vertical direction of the surface is from t / 3. A region up to 2t / 3 is defined as a second region, and a region having a distance from the surface in the vertical direction of the surface from 2t / 3 to t is defined as a third region. Note that t / 3, which is the boundary value between the first region and the second region, is not included in the first region but is included in the second region. Further, 2t / 3 which is a boundary value between the second region and the third region is not included in the second region but is included in the third region. At this time, when the average porosity of the first region is P1, the average porosity of the second region is P2, and the average porosity of the third region is P3, P1 <P2 <P3 is satisfied. Moreover, P2 / P1 satisfies 1.1 or more and 1.4 or less, and preferably satisfies 1.2 or more and 1.3 or less. By reducing the average porosity P1 in the first region having the surface in contact with the nozzle forming surface, the scraping force of the liquid fixed substance can be improved. Further, the average porosity P3 is set to 1.1 or more and 1.4 or less to provide a difference in the average porosity between the first region and the second region, and then the average porosity P3 is set to the average porosity P2. By making it larger, excess liquid on the nozzle forming surface can be quickly absorbed into the wiping member. Thereby, the removal of the liquid adhering substance on the nozzle formation surface and the absorption of the excess liquid on the nozzle formation surface can be efficiently and simultaneously performed.

In the present embodiment, the average void ratios P1, P2, and P3 of each region are calculated by the following method as an example.
First, the wiping member is cut out in a 1 cm square shape, and its cross section is observed with a laser microscope to obtain the thickness t of the wiping member in the vertical direction of the surface. Next, in the first region specified from the thickness t, five cross-sectional images are taken, and the void ratio is calculated by calculating “the area occupied by the void portion / the area of the wiping member” in each image. An average of the five void ratios is defined as an average void ratio P1. Then, similarly to P1, the average porosity P2 is obtained from the cross-sectional image of the second region, and the average porosity P3 is obtained from the cross-sectional image of the third region. The “area of the wiping member” is the sum of the area occupied by the material of the wiping member and the area occupied by the gap portion of the wiping member. Further, the thickness t may be measured with a micrometer, a laser displacement meter, or the like other than the laser microscope.

  The average porosity P1 is preferably 0.50 or more and 0.84 or less, more preferably 0.60 or more and 0.80 or less, further preferably 0.60 or more and 0.75 or less, It is particularly preferably 0.65 or more and 0.75 or less. The wiping member has a mean void ratio P1 of 0.50 or more, so that it is easy to take in the liquid fixed substance inside the wiping member, and when it is 0.84 or less, the contact area where the fibers of the wiping member are in contact with the liquid fixed substance is increased. It is possible to increase the size, and it is possible to improve the scraping force of the liquid adhering material by the wiping member.

  The average porosity P2 is preferably from 0.55 to 0.94, more preferably from 0.66 to 0.94, still more preferably from 0.80 to 0.94, It is particularly preferably 0.85 or more and 0.94 or less. The wiping member has an average porosity P2 of 0.55 or more and 0.94 or less, so that a reduction in the scraping force of the liquid adhering matter is suppressed, and the excess liquid absorbed in the first region can be quickly absorbed into the third region. Can lead to.

  The average porosity P3 is preferably 0.65 or more and 0.99 or less, more preferably 0.80 or more and 0.99 or less, further preferably 0.85 or more and 0.99 or less, It is particularly preferably 0.90 or more and 0.99 or less. The amount of excess liquid that can be absorbed by the wiping member increases when the average porosity P3 is 0.65 or more and 0.99 or less.

  The thickness t of the wiping member is preferably 0.1 mm or greater and 3.0 mm or less, and more preferably 0.2 mm or greater and 1.7 mm or less. When the thickness t of the wiping member is 0.1 mm or more, the saturated water absorption amount of the liquid per unit area of the wiping member becomes good, and the liquid to be wiped can be sufficiently absorbed. Moreover, when the thickness t of the wiping member is 3.0 mm or less, the apparatus can be downsized.

  As the wiping member in the present embodiment, for example, a single-layer wiping member whose porosity changes continuously, a plurality of layers whose porosity changes stepwise by combining a plurality of members with a bonding material such as an adhesive. Although it can be appropriately selected from the wiping member according to the purpose and used, the single layer wiping member is preferable. By using the single-layer wiping member, the speed of absorbing excess liquid on the nozzle forming surface is improved. Moreover, if it is the said single layer wiping member, it will become unnecessary to join using the joining materials, such as an adhesive agent, between several members which comprise a wiping member. Therefore, the liquid absorption efficiency is not lowered by the bonding material such as the adhesive, and the liquid can be quickly absorbed to the vicinity of the back surface of the wiping member. Further, since the bonding material such as the adhesive does not melt when the wiping member is used, it is possible to suppress the influence on the member with which the wiping member such as the nozzle forming surface comes into contact.

  The wiping member in this embodiment can be appropriately selected according to the purpose from nonwoven fabric, woven fabric, knitting, etc., but at least the surface of the wiping member is preferably a nonwoven fabric, and the entire wiping member is a nonwoven fabric. It is more preferable that In the woven fabric and knitting, the fiber direction is a specific direction, whereas in the nonwoven fabric, the fiber direction is random. For this reason, when wiping the liquid adhering material on the nozzle forming surface, the contact area between the wiping member and the liquid adhering material increases, and the wiping member and the liquid adhering material are easily entangled, and the liquid adhering material removal efficiency is increased. Will improve.

  Examples of the material of the wiping member include cotton, hemp, silk, pulp, nylon, vinylon, polyester, polypropylene, polyethylene, rayon, cupra, acrylic, and polylactic acid. Not only the wiping member made of one type of material but also a wiping member in which a plurality of types of materials are mixed may be used.

  The surface that is the wiping surface of the wiping member preferably has a surface roughness Rz obtained by measuring the surface roughness with a laser microscope or the like of 170 μm or more. When the surface roughness Rz of the wiping surface is 170 μm or more, it becomes difficult to break the meniscus in the nozzle, and it is possible to wipe the nozzle forming surface while suppressing the occurrence of ejection failure.

  As an example of the manufacturing method of the wiping member, a case where the wiping member is a nonwoven fabric will be described. Examples of the method for forming the nonwoven fabric include wet, dry, spunbond, meltblown, and flash spinning methods. Moreover, as a bonding method of a nonwoven fabric, methods, such as a spunlace, a needle punch, a thermal bond, a chemical bond, are mentioned, for example. The spunlace method is a manufacturing method in which a jet water stream is sprayed on the deposited fibers, and the fibers are entangled with each other by the pressure to bond them in a sheet form. The needle punch method is a manufacturing method in which fibers are mechanically entangled and processed into a nonwoven fabric by piercing a deposited fiber called a barb with a needle with a protrusion several tens of times. The fiber layer is laminated in the order of coarse layer, middle layer and dense layer so that the fiber density increases in order, and the voids are continuous by tangling the constituent fibers together by the spunlace method, needle punch method, etc. Single layer non-woven fabrics can be produced.

  The wiping member may be combined with another member for purposes other than liquid wiping. For example, a film or the like may be lined for the purpose of preventing the absorbed liquid from showing through and improving the strength of the wiping member.

<< Wiping device >>
The wiping device of this embodiment has the wiping member described above, and wipes the nozzle forming surface by bringing the wiping member into contact with the nozzle forming surface. Further, the wiping device includes a cleaning liquid applying unit that applies a cleaning liquid to the wiping member as necessary.

  Next, the wiping device will be described using FIG. 2 and FIG. 3 as an example of an image forming apparatus which is an example of a device incorporating the wiping device. An image forming apparatus is an apparatus that ejects ink as an example of a liquid. FIG. 2 is a diagram schematically illustrating an example of an image forming apparatus incorporating the wiping device. FIG. 3 is a diagram schematically illustrating an example of the nozzle formation surface of the liquid ejection head. FIG. 4 is a diagram schematically illustrating an example of the wiping device.

  The image forming apparatus shown in FIG. 2 is a serial type liquid ejecting apparatus. In the image forming apparatus, a carriage 3 is movably held by a main guide member 1 and a secondary guide member that are horizontally mounted on left and right side plates. The carriage 3 is reciprocated in the main scanning direction (carriage moving direction) by the main scanning motor 5 via the timing belt 8 spanned between the driving pulley 6 and the driven pulley 7. On the carriage 3, recording heads 4a and 4b (an example of a liquid discharge head, referred to as “recording head 4” when not distinguished) are mounted. For example, the recording head 4 ejects ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). The recording head 4 is mounted with a nozzle row composed of a plurality of nozzles arranged in the sub-scanning direction orthogonal to the main scanning direction and with the droplet discharge direction facing downward.

  As shown in FIG. 3, the recording head 4 has two nozzle rows Na and Nb in which a plurality of nozzles 4 n are arranged on the nozzle forming surface 41. As the liquid discharge head constituting the recording head 4, for example, a piezoelectric actuator such as a piezoelectric element, or a thermal actuator that uses a phase change caused by liquid film boiling using an electrothermal transducer such as a heating resistor can be used. .

  The image forming apparatus shown in FIG. 2 includes a conveyance belt 12 that is a conveyance unit for conveying the sheet 10 at a position opposite to the recording head 4 by electrostatically attracting the sheet. The transport belt 12 is an endless belt and is stretched between the transport roller 13 and the tension roller 14. The conveyor belt 12 is rotated in the sub-scanning direction by the sub-scanning motor 16 being driven to rotate by the sub-scanning motor 16 via the timing belt 17 and the timing pulley 18. The conveyor belt 12 is charged (charged) by a charging roller while moving around.

  Further, a maintenance / recovery mechanism 20 that performs maintenance / recovery of the recording head 4 on the side of the conveyance belt 12 is arranged on one side of the carriage 3 in the main scanning direction, and the recording head 4 is arranged on the side of the conveyance belt 12 on the other side. The empty discharge receptacles 21 for performing empty discharge are respectively disposed. The maintenance / recovery mechanism 20 includes, for example, a cap member 20a for capping the nozzle formation surface (surface on which the nozzles are formed) of the recording head 4, a mechanism 20b for wiping the nozzle formation surface, and an idle discharge for discharging droplets that do not contribute to image formation. It consists of a receiver.

  In the image forming apparatus, an encoder scale 23 having a predetermined pattern is stretched between both side plates along the main scanning direction of the carriage 3. Further, the carriage 3 is provided with an encoder sensor 24 composed of a transmissive photosensor that reads the pattern of the encoder scale 23. These encoder scale 23 and encoder sensor 24 constitute a linear encoder (main scanning encoder) that detects the movement of the carriage 3.

  A code wheel 25 is attached to the shaft of the transport roller 13, and an encoder sensor 26 including a transmission type photo sensor that detects a pattern formed on the code wheel 25 is also provided. These code wheel 25 and encoder sensor 26 constitute a rotary encoder (sub-scanning encoder) that detects the movement amount and movement position of the conveyor belt 12.

  In the image forming apparatus configured as described above, the sheet 10 is sucked by being fed onto the charged conveying belt 12, and the sheet 10 is conveyed in the sub-scanning direction by the circular movement of the conveying belt 12. Therefore, by driving the recording head 4 according to the image signal while moving the carriage 3 in the main scanning direction, ink droplets are ejected onto the stopped paper 10 to record one line. Then, after the sheet 10 is conveyed by a predetermined amount, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing edge of the paper 10 has reached the recording area, the recording operation is finished, and the paper 10 is discharged onto a paper discharge tray.

When cleaning the recording head 4, the carriage 3 is moved to the maintenance / recovery mechanism 20 during printing (recording) standby, and the maintenance / recovery mechanism 20 performs cleaning. The recording head 4 may not be moved, and the maintenance / recovery mechanism 20 may be moved to clean the head. The recording head 4 shown in FIG. 2 has two nozzle rows Na and Nb in which a plurality of nozzles 4n are arranged as shown in FIG. One nozzle row Na of the recording head 4a discharges black (K) droplets, and the other nozzle row Nb discharges cyan (C) droplets. One nozzle row Na of the recording head 4b discharges magenta (M) droplets, and the other nozzle row Nb discharges yellow (Y) droplets.

  The mechanism 20b for wiping the nozzle forming surface is an example of a wiping device, and as shown in FIG. 4, a sheet-like wiping member 320 which is an example of a wiping member, a delivery roller 410 for feeding out the sheet-like wiping member 320, and a delivery A cleaning liquid application roller 430 that is an example of a cleaning liquid application unit that applies a cleaning liquid to the sheet-like wiping member 320; a pressing roller 400 that presses the sheet-like wiping member 320 to which the cleaning liquid is applied; And a take-up roller 420 that collects the used sheet-like wiping member 320. The mechanism 20b for wiping the nozzle forming surface may include a rubber blade or the like for wiping the nozzle forming surface in addition to the sheet-like wiping member 320. The pressing roller 400 can adjust the pressing force by adjusting the distance between the cleaning unit and the nozzle forming surface using a spring. The pressing member is not limited to a roller, and may be a fixed resin or rubber member. When a rubber blade or the like is provided, a mechanism for bringing the rubber blade or the like into contact with the sheet-like wiping member 320 may be provided so that the sheet-like wiping member 320 has a cleaning function such as a rubber blade.

<Cleaning liquid>
The cleaning liquid preferably contains an organic solvent, water, a surfactant, and the like, and has a surface tension of 35 mN / m or less. By wiping the cleaning liquid after applying the cleaning liquid to the sheet-like wiping member 320, the viscosity of the liquid adhering matter formed on the nozzle forming surface is reduced and the removal becomes easy. For example, a cleaning liquid is applied to the sheet-like wiping member 320 for an ink-fixed matter that is an example of a liquid-fixed matter on the nozzle forming surface caused by waiting the image forming apparatus for a long time. In 320, it is preferable to wipe the nozzle forming surface a plurality of times or for a predetermined time or more.

-Organic solvent-
It does not restrict | limit especially as an organic solvent used for a washing | cleaning liquid, A water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds.
Specific examples of the polyhydric alcohol include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3- Hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol, and the like.
Examples of the polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether and the like.
Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Examples of nitrogen-containing heterocyclic compounds include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone. Can be mentioned.
Examples of amides include formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide and the like.
Examples of amines include monoethanolamine, diethanolamine, and triethylamine.
Examples of sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol and the like.
Examples of other organic solvents include propylene carbonate and ethylene carbonate.

As the organic solvent, a polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and the like.
Specific examples of glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of ethers include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

  There is no restriction | limiting in particular in content in the washing | cleaning liquid of an organic solvent, According to the objective, it can select suitably, 10 mass% or more and 60 mass% or less are preferable, and 20 mass% or more and 60 mass% or less are more preferable.

-Water-
The content of water in the cleaning liquid is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass or more and 90% by mass or less, and 20% by mass from the viewpoint of drying property and ejection reliability of the cleaning liquid. % To 60% by mass is more preferable.

-Surfactant-
As the surfactant, any of silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants and anionic surfactants can be used.
There is no restriction | limiting in particular in silicone type surfactant, According to the objective, it can select suitably. Among them, those that do not decompose even at high pH are preferable. Examples of the silicone surfactant include side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, and side chain both terminal modified polydimethylsiloxane. Those having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group are particularly preferred because they exhibit good properties as an aqueous surfactant. Moreover, a polyether modified silicone surfactant can also be used as a silicone surfactant, for example, the compound etc. which introduce | transduced the polyalkylene oxide structure into the Si part side chain of dimethylsiloxane are mentioned.
Examples of the fluorosurfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because of their low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonate. Examples of the perfluoroalkyl carboxylic acid compound include perfluoroalkyl carboxylic acid and perfluoroalkyl carboxylate. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include a polyoxyalkylene ether polymer sulfate salt having a perfluoroalkyl ether group in the side chain, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain. Examples thereof include salts of oxyalkylene ether polymers. As counter ions of salts in these fluorosurfactants, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH) ₃ etc. are mentioned.
Examples of amphoteric surfactants include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Nonionic surfactants include, for example, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate salt, and the like.
These may be used alone or in combination of two or more.

The silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, side chain Examples thereof include polydimethylsiloxane modified at both ends, and a polyether-modified silicone surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group is particularly preferable because it exhibits good properties as an aqueous surfactant. .
As such a surfactant, an appropriately synthesized product or a commercially available product may be used. Commercially available products can be obtained from, for example, Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd.
There is no restriction | limiting in particular as said polyether modified silicone surfactant, According to the objective, it can select suitably, For example, the polyalkylene oxide structure represented by a general formula (S-1) type | formula is dimethylpolyethylene. Examples thereof include those introduced into the side chain of Si part of siloxane.
(However, in the formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R ′ represents an alkyl group.)
A commercial item can be used as said polyether modified silicone type surfactant, For example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Japan Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (Bic Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.), etc. are mentioned.

As the fluorine-based surfactant, a fluorine-substituted compound having 2 to 16 carbon atoms is preferable, and a fluorine-substituted compound having 4 to 16 carbon atoms is more preferable.
Examples of the fluorosurfactant include perfluoroalkyl phosphate compounds, perfluoroalkylethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain. Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because of its low foaming property, and in particular, fluorine-based compounds represented by the general formulas (F-1) and (F-2) A surfactant is preferred.
In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.
In the compound represented by the general formula (F-2), Y is H, or CmF _{2m + 1} , m is an integer of 1 to 6, or CH ₂ CH (OH) CH ₂ —CmF _{2m + 1,} where m is 4 to 6. An integer, or CpH _{2p + 1} , p is an integer of 1-19. n is an integer of 1-6. a is an integer of 4-14.
A commercial item may be used as said fluorosurfactant. As this commercial item, for example, Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Limited); Megafac F-470, F -1405, F-474 (all manufactured by Dainippon Ink & Chemicals, Inc.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by Chemours); FT-110, FT-250 FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (Omnova) And Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.). Among these, FS-3100, FS-34 and FS-300 manufactured by Chemours, FT-110 and FT- manufactured by Neos Co., Ltd. 250, FT-251, FT-400S, FT-150, FT-400SW, Omnova's Polyfox PF-151N and Daikin Industries, Ltd.'s Unidyne DSN-403N are particularly preferred.

  There is no restriction | limiting in particular as content of surfactant in a washing | cleaning liquid, Although it can select suitably according to the objective, 0.001 mass% or more and 5 mass% or less are preferable, 0.05 mass% or more and 5 mass% % Or less is more preferable.

There is no restriction | limiting in particular as a physical property of a washing | cleaning liquid, According to the objective, it can select suitably, For example, it is preferable that a viscosity, surface tension, pH, etc. are the following ranges.
The viscosity of the cleaning liquid at 25 ° C. is preferably 5 mPa · s to 30 mPa · s, and more preferably 5 mPa · s to 25 mPa · s. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. Measurement conditions are 25 ° C., standard cone rotor (1 ° 34 ′ × R24), sample liquid amount 1.2 mL, rotation speed 50 rpm, and measurement is possible for 3 minutes.
The surface tension of the cleaning liquid is preferably 35 mN / m or less, more preferably 32 mN / m or less at 25 ° C.
The pH of the cleaning liquid is preferably 7 to 12 and more preferably 8 to 11 from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

<< Wiping method >>
The wiping method of this embodiment includes the wiping process of wiping the nozzle forming surface by using the wiping member and bringing the wiping member into contact with the nozzle forming surface. Moreover, the wiping method has a washing | cleaning liquid provision process which provides a washing | cleaning liquid with respect to a wiping member before a wiping process as needed. This wiping method will be described with reference to FIG.

<Washing liquid application process>
The cleaning liquid application process is a process of applying the cleaning liquid to the sheet-like wiping member 320 using the cleaning liquid application roller 430. The application amount of the cleaning liquid is preferably 30 μl / cm ² or less. When the application amount of the cleaning liquid is within this range, when P2 / P1 is 1.1 or more and 1.4 or less, the cleaning liquid applied to the sheet-like wiping member 320 by bringing the sheet-like wiping member 320 into contact with the nozzle forming surface. Oozes out uniformly on the nozzle forming surface. This facilitates removal of the liquid adhering matter formed on the nozzle forming surface.

<Wiping process>
In the wiping step, after the cleaning liquid is applied to the sheet-like wiping member 320, the sheet-like wiping member 320 and the recording head 4 move relative to each other while pressing the wiping member against the nozzle-forming surface, so that the foreign matter adhered to the nozzle-forming surface. This is a step of wiping 500. Examples of the foreign matter 500 adhering to the nozzle forming surface include mist ink generated when ink is ejected from the nozzle, ink adhering when ink is sucked from the nozzle during cleaning, ink adhering to the mist ink and cap member. Examples thereof include fixed ink dried on the nozzle forming surface and paper dust generated from the substrate.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Adjustment of cleaning liquid>
The following components were mixed and stirred to prepare a cleaning solution. In addition, it was 28 mN / m when the surface tension of this cleaning liquid was measured with a surface tension meter (CBVP-Z type, manufactured by Kyowa Interface Science Co., Ltd.).
・ 3-Methoxy-3-methyl-1-butanol (Kuraray Co., Ltd.) 20% by mass
-Polyether-modified silicone surfactant (trade name: WET270, manufactured by Evonik Degussa Japan) 1% by mass
・ Ion exchange water remaining

(Examples 1-13, Comparative Examples 1-4)
[Average porosity measurement]
A sheet-like wiping member having the structure and material shown in Table 1 below was prepared. Next, each wiping member was cut out in a 1 cm square shape, and a cross section thereof was observed with a laser microscope (trade name: LEXT OLS4100, manufactured by Olympus) to obtain a thickness t of the wiping member in the vertical direction of the surface. Next, in the first region specified from the thickness t, five cross-sectional images are taken, and fibers (wiping member material) and gaps are captured using image analysis software (Image-Pro Plus, manufactured by Nippon Roper). Binarization was carried out to (void). Thereafter, the void ratio was calculated by calculating “the area occupied by the void portion / the area of the wiping member” in each image, and an average void ratio P1 that was an average of the five void ratios was calculated. In the same manner as P1, the average porosity P2 was calculated from the cross-sectional image of the second region, and the average porosity P3 was calculated from the cross-sectional image of the third region. The “area of the wiping member” is the sum of the area occupied by the material of the wiping member and the area occupied by the gap portion of the wiping member. Table 1 below shows the values of average porosity P1, P2, P3, and P2 / P1 in the wiping members of Examples 1 to 13 and Comparative Examples 1 to 3. The “nonwoven fabric (multilayer)” in Example 12 of Table 1 below indicates a nonwoven fabric obtained by bonding a plurality of nonwoven fabrics with an adhesive.

  Next, regarding the wiping members of Examples 1 to 13 and Comparative Examples 1 to 4, the wiping property of the liquid fixed substance and the wiping property of the excess liquid were evaluated according to the following method and evaluation criteria. The evaluation results are shown in Table 1 below.

<Wipeability of liquid adhering matter>
0.1 ml of RICOH Pro AR Ink White (manufactured by Ricoh Co., Ltd.) was dropped on the nozzle forming surface of an ink jet head (MH5440, manufactured by Ricoh Co., Ltd.), and then left for 15 hours to allow the ink to adhere to the nozzle forming surface. Was made. Next, after applying the cleaning liquid to the wiping member so as to be 10 μl / cm ² , the nozzle forming surface of the ink jet head to which the ink was fixed was wiped with the wiping member. The conditions for wiping were a pressing force of 3 N and a wiping speed of 50 mm / s. By visually observing the nozzle forming surface after wiping, the number of wiping times required until the fixed ink was removed was counted, and the rank was evaluated based on the following evaluation criteria. The case where evaluation was C or more was judged to be practical.
〔Evaluation criteria〕
A: The fixed ink on the nozzle forming surface was removed with the number of wiping times of 5 or less B: The fixed ink on the nozzle forming surface was removed with the number of wiping times of 6 to 7 times C: 8 to 10 times The fixed ink on the nozzle forming surface was removed by the following number of wiping operations. D: The fixed ink on the nozzle forming surface remained after wiping 10 times.

<Removability of excess liquid>
1 ml of RICOH Pro AR Ink White (manufactured by Ricoh Co., Ltd.) was dropped on the nozzle forming surface of an ink jet head (MH5440, manufactured by Ricoh Co., Ltd.) to produce an ink jet head in which excess ink adhered to the nozzle forming surface. Next, after applying the cleaning liquid to the wiping member so as to be 10 μl / cm ² , the nozzle forming surface of the inkjet head to which the excess ink adhered was wiped with the wiping member. The wiping condition was a pressing force of 3N. Further, when the wiping speed is set to 30 mm / s, 50 mm / s, or 70 mm / s, the wiping of the excess liquid is observed by visually observing the nozzle forming surface after wiping. Sex was evaluated. Specifically, the rank was evaluated based on the following evaluation criteria. The case where evaluation was C or more was judged to be practical.
〔Evaluation criteria〕
A: Excess ink on the nozzle formation surface was removed at all wiping speeds B: Excess ink on the nozzle formation surface was removed when the wiping speed was 30 mm / s and 50 mm / s. Excess ink remained when 70 mm / s C: Excess ink on the nozzle forming surface was removed when the wiping speed was 30 mm / s, but 70 mm / s and 70 mm / s In this case, surplus ink remained D: surplus ink on the nozzle forming surface remained at all wiping speeds

In the wiping member having no change in the average porosity in the vertical direction of the surface as in Comparative Example 1, the fixed ink remains even after wiping 10 times in the wiping property evaluation of the liquid fixed matter, and in the wiping property evaluation of the excess liquid. Excess ink remained at all wiping speeds.
As in Comparative Example 2, the wiping member having an average void ratio P1 larger than the average void ratios P2 and P3, the fixed ink remains even after wiping 10 times in the wiping property evaluation of the liquid fixed matter, and the wiping property evaluation of the excess liquid In FIG. 4, surplus ink remained at all wiping speeds.
In the wiping member having P2 / P1 larger than 1.4 as in Comparative Example 3, in the evaluation of the wiping property of the surplus liquid, the surplus ink once absorbed by the wiping member again adhered to the nozzle forming surface, and the surplus ink remained.
As in Comparative Example 4, in the wiping member having an average void ratio P2 larger than the average void ratios P1 and P3, excess ink remained at all wiping speeds in the evaluation of the wiping property of the excess liquid.

3 Carriage 4, 4a, 4b Recording head 4n Nozzle 20 Maintenance recovery mechanism 20b Mechanism for wiping the nozzle forming surface 41 Nozzle forming surface 320 Sheet-like wiping member 400 Pressing roller 410 Feeding roller 420 Take-up roller 430 Cleaning liquid application roller 500 Foreign matter

Japanese Patent No. 6162344

Claims (11)

A wiping member for wiping the nozzle forming surface of the liquid ejection head,
The thickness of the wiping member in the vertical direction of the surface contacting the nozzle forming surface of the wiping member is t, and the distance from the surface in the vertical direction is a region from 0 to t / 3. An average porosity is P1, an average porosity of the second region, which is a region where the distance is from t / 3 to 2t / 3, is P2, and a third region where the distance is a region from 2t / 3 to t. When the average porosity of the region is P3, P1 <P2 <P3 is satisfied,
P2 / P1 is a wiping member that is 1.1 or more and 1.4 or less.   The wiping member according to claim 1, wherein the P1 is 0.60 or more and 0.80 or less.   The wiping member according to claim 1, wherein the surface of the wiping member is a nonwoven fabric.   The wiping member according to any one of claims 1 to 3, wherein the P2 / P1 is 1.2 or more and 1.3 or less.   The wiping member according to any one of claims 1 to 4, wherein the wiping member is a single layer. Using a wiping member that wipes the nozzle forming surface of the liquid ejection head, including a wiping step of wiping the nozzle forming surface;
The thickness of the wiping member in the vertical direction of the surface contacting the nozzle forming surface of the wiping member is t, and the distance from the surface in the vertical direction is a region from 0 to t / 3. An average porosity is P1, an average porosity of the second region, which is a region where the distance is from t / 3 to 2t / 3, is P2, and a third region where the distance is a region from 2t / 3 to t. When the average porosity of the region is P3, P1 <P2 <P3 is satisfied,
P2 / P1 is a wiping method of 1.1 or more and 1.4 or less.   The wiping method of Claim 6 including the washing | cleaning liquid provision process which provides a washing | cleaning liquid with respect to the said wiping member before the said wiping process.   The wiping method according to claim 7, wherein the cleaning liquid has a surface tension of 35 mN / m or less. Having a wiping member for wiping the nozzle forming surface of the liquid ejection head;
The thickness of the wiping member in the vertical direction of the surface contacting the nozzle forming surface of the wiping member is t, and the distance from the surface in the vertical direction is a region from 0 to t / 3. An average porosity is P1, an average porosity of the second region, which is a region where the distance is from t / 3 to 2t / 3, is P2, and a third region where the distance is a region from 2t / 3 to t. When the average porosity of the region is P3, P1 <P2 <P3 is satisfied,
P2 / P1 is a wiping device that is 1.1 or more and 1.4 or less.   The wiping apparatus according to claim 9, further comprising a cleaning liquid applying unit that applies a cleaning liquid to the wiping member.   The wiping device according to claim 10, wherein the cleaning liquid has a surface tension of 35 mN / m or less.