Ink ejection device

Abstract

The present invention provides an ink ejection device that can easily wipe away both solidified ink and high-viscosity ink adhering to the nozzle surface using a wiper. [Solution] The printer 10 includes a print head 34 having a nozzle surface 33A through which ink nozzles 33 are opened, a wipe unit 121 for wiping the nozzle surface 33A, and a belt movement mechanism 171 for moving the print head 34 in the left-right direction relative to the wipe unit 121. The wipe unit 121 includes a first discharge section 123 for discharging cleaning fluid onto the nozzle surface 33A, and a first wiper 125 and a second wiper 128 that contact the nozzle surface 33A. The first discharge section 123, the first wiper 125, and the second wiper 128 are arranged in this order in the left-right direction.

Description

Technical Field

[0001] The present disclosure relates to an ink ejection device including a wiper that wipes ink adhering to a nozzle surface.

Background Art

[0002] For example, in the wiping device according to Patent Document 1, a cleaning liquid is supplied from a supply plate before the wiper blade reaches the head nozzle. Thereby, the cleaning liquid spreads between the wiper blade and the nozzle forming surface, and the wiper blade becomes wet. Next, the nozzle forming surface is wiped by moving the wiper blade while contacting the nozzle forming surface. Thereby, the ink adhering to the nozzle forming surface is wiped off.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the wiping device of Patent Document 1, the ink adhering to the nozzle forming surface may become fixed ink fixed to the nozzle surface or high-viscosity ink due to drying. In this case, in the wiping device of Patent Document 1, it may be difficult to wipe off the fixed ink and the high-viscosity ink from the nozzle forming surface.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide an ink ejection device capable of easily wiping both fixed ink and high-viscosity ink adhering to the nozzle surface from the nozzle surface with a wiper.

Means for Solving the Problems

[0006] (1) This disclosure relates to an ink ejection device. The ink ejection device comprises a head having a nozzle surface from which an ink ejection nozzle opens, a wipe unit for wiping the nozzle surface, and a moving mechanism for moving the head and the wipe unit relative to each other in a first direction. The wipe unit has a discharge section for discharging cleaning fluid onto the nozzle surface, and a first wiper and a second wiper that contact the nozzle surface. The discharge section, the first wiper, and the second wiper are arranged in this order in the first direction.

[0007] As the wipe unit and the head move relative to each other in a first direction, the cleaning solution is supplied to the nozzle surface. At this time, even if the ink adhering to the nozzle surface has dried and hardened, the hardened ink will deform as it comes into contact with the cleaning solution and is pressed in the first direction by the first wiper, making it softer and allowing the cleaning solution to penetrate more easily. In this state, the second wiper presses the hardened ink in the first direction. As a result, the second wiper can easily wipe away the hardened ink from the nozzle surface. Similarly, even if the ink adhering to the nozzle surface has dried and hardened, the viscosity of the hardened ink decreases when the cleaning solution comes into contact with it, making it easier to remove from the nozzle surface. As a result, the first and second wipers can easily wipe away the hardened ink from the nozzle surface. [Effects of the Invention]

[0008] According to this disclosure, both solidified ink and high-viscosity ink adhering to the nozzle surface can be easily wiped away from the nozzle surface by a wiper. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view of printer 10. [Figure 2] Figure 2 is a schematic diagram showing the internal configuration of the printer 10. [Figure 3]Figure 3 shows the belt movement mechanism 171 that moves the carriage 40 in the left-right direction. [Figure 4] Figure 4 shows the cap 71 moving upward and making close contact with the nozzle surface 33A. [Figure 5] Figure 5 is a cross-sectional view of the wipe unit 121 cut by a plane perpendicular to the front-to-back direction. [Figure 6] Figure 6 is a schematic diagram of the wipe unit 121 as seen from above. [Figure 7] Figure 7 shows the wiping lateral load F1 of the second wiper, the adhesion force F2 of the solidified ink, and the maximum static friction force F3 generated between the solidified ink and the nozzle surface 33A. [Figure 8] Figure 8 shows the method for measuring the lateral load F1 during wiping. [Figure 9] Figure 9 is a schematic diagram showing the wipe unit 121 connected to the cleaning fluid tank 17 and the waste ink tank 81. [Figure 10] Figure 10 is a functional block diagram of printer 10. [Figure 11] Figure 11 is a flowchart of the maintenance process. [Figure 12] Figure 12 shows the state in which the first wiper 125 and the second wiper 128 are wiping the nozzle surface 33A. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described below with reference to the drawings as appropriate. It should be noted that the embodiments described below are merely examples of this disclosure, and the embodiments of this disclosure can be modified as appropriate without altering the gist of this disclosure. In the following description, the vertical direction is defined based on the state in which the printer 10 is installed for use (the state in Figure 1). The front-to-back direction is defined with the side from which the paper feed tray 23 is pulled out of the printer 10 as the front. The left-to-right direction is defined when viewing the printer 10 from the front.

[0011] [External configuration of printer 10] As shown in FIGS. 1 and 10, a printer 10 (an example of an ink ejection device) includes a housing 13, an operation unit 21 held by the housing 13, a cover 22, a paper feed tray 23, a paper discharge tray 24, a controller 130, and a memory 140. The printer 10 records an image on a sheet 6 (see FIG. 2).

[0012] The sheet 6 may be a recording medium cut to a predetermined size, may be drawn from a roll wound in a cylindrical shape, or may be of a fan-fold type.

[0013] The operation unit 21 includes a display and a plurality of operation switches. The operation unit 21 receives a user's operation. The operation unit 21 may be a touch panel.

[0014] As shown in FIG. 1, the paper feed tray 23 is located below the housing 13. The paper discharge tray 24 is below the housing 13 and is located above the paper feed tray 23. The cover 22 is located on the right side of the front surface of the housing 13. The cover 22 is rotatably attached to the lower end of the housing 13. When the cover 22 is opened, access to a cartridge 70 that stores ink is possible.

[0015] In this embodiment, the cartridge 70 is not limited to storing one color of ink such as black, and may be, for example, four cartridges 70 that store four inks of black, yellow, cyan, and magenta respectively.

[0016] [Printing engine 50] As shown in Figure 2, the housing 13 houses the printing engine 50. The printing engine 50 mainly comprises a feed roller 25, a transport roller 26, an ejection roller 27, a platen 28, and a print head 34 (an example of a head). The feed roller 25 is rotatably supported by an arm 29. The arm 29 is rotatably supported by a frame provided inside the housing 13. The feed roller 25 contacts the sheet 6 placed on the paper tray 23. When the feed motor 102 (see Figure 10) is driven and the feed roller 25 rotates, the sheet 6 is fed from the paper tray 23 to the transport path 37. The transport path 37 is a space partitioned by guide members (not shown). In this embodiment, the transport path 37 extends upward curving from the rear end of the paper tray 23, and then extends forward.

[0017] The transport roller 26 and the driven roller 35 are located downstream of the paper feed tray 23 in the sheet 6 transport direction 4. The driven roller 35 is biased toward the transport roller 26 by a spring. The driven roller 35 holds the sheet 6 between itself and the transport roller 26. When the transport motor 101 (see Figure 10) is driven and the transport roller 26 rotates, the sheet 6 held between itself and the driven roller 35 is transported in the transport direction 4.

[0018] The discharge roller 27 and the driven roller 36 are located downstream of the conveying roller 26 in the conveying direction 4. The driven roller 36 is biased toward the discharge roller 27 by a spring. The driven roller 36 holds the sheet 6 between itself and the discharge roller 27. When the drive of the conveying motor 101 (see Figure 10) is transmitted and the discharge roller 27 rotates, the sheet 6 held between itself and the driven roller 36 is conveyed in the conveying direction 4.

[0019] The platen 28 is positioned between the conveying roller 26 and the discharge roller 27 in the front-rear direction. The platen 28 supports the sheet 6 on its upper surface.

[0020] The print head 34 is located between the transport roller 26 and the discharge roller 27 in the front-to-back direction. In the up-to-down direction, the print head 34 is located above the platen 28. The print head 34 has an internal flow path through which ink flows. The flow path is connected to the cartridge 70 by a tube 31. Ink is supplied from the cartridge 70 to the print head 34 through the tube 31. The lower surface of the print head 34 is the nozzle surface 33A. The nozzle surface 33A extends in the front-to-back and left-to-right directions. Multiple nozzles 33 open on the nozzle surface 33A. When the piezoelectric element 45 (see Figure 10) corresponding to each nozzle 33 is driven, ink droplets are ejected from each nozzle 33.

[0021] As shown in Figure 3, the print head 34 is mounted on a carriage 40. The carriage 40 is movably supported by guide rails 43 and 44 that extend in the left-right direction. Guide rail 44 is positioned in front of guide rail 43 at a distance. The carriage 40 is connected to a belt movement mechanism 171 provided on guide rail 44. The belt movement mechanism 171 includes a carriage drive motor 181, a drive pulley 182, a driven pulley 183, and a belt 184.

[0022] The carriage drive motor 181 is fixed to the right end of the lower surface of the front guide rail 44. The drive shaft of the carriage drive motor 181 extends upward. The drive pulley 182 is rotatably supported at the right end of the upper surface of the front guide rail 44. The rotation shaft 182A of the drive pulley 182 extends vertically. The rotation shaft 182A of the drive pulley 182 is connected to the drive shaft of the carriage drive motor 181. The driven pulley 183 is rotatably supported at the left end of the upper surface of the front guide rail 44. The rotation shaft 183A of the driven pulley 183 extends vertically. The belt 184 is stretched over the drive pulley 182 and the driven pulley 183. A portion of the belt 184 is fixed to the carriage 40. As a result, the carriage 40 can reciprocate in the left-right direction by transmitting the driving force of the carriage drive motor 181 to the belt 184. The carriage 40 can move in the left-right direction to a position to the right of the wipe unit 121 (hereinafter referred to as the standby position). In Figure 3, the standby position is indicated by dashed lines. The print head 34 moves together with the carriage 40. The belt movement mechanism is an example of a movement mechanism.

[0023] The ink ejected from the multiple nozzles 33 is an aqueous ink containing at least a water-soluble organic solvent and water. The aqueous ink is not particularly limited as long as it contains at least a water-soluble organic solvent and water. Specifically, the aqueous ink contains resin fine particles, a colorant, a water-soluble organic solvent, water, and additives. The viscosity of the aqueous ink is preferably in the range of 1 mPa·s to 15 mPa·s.

[0024] As resin fine particles, for example, those containing at least one of methacrylic acid and acrylic acid as monomers can be used, and commercially available products may be used, for example. The resin fine particles may further contain styrene, vinyl chloride, etc. as monomers, for example. The resin fine particles may be contained in an emulsion, for example. The emulsion is composed of resin fine particles and a dispersion medium (for example, water, etc.). The resin fine particles are not dissolved in the dispersion medium but are dispersed within a specific particle size range. Examples of resin fine particles include acrylic acid resins, maleic acid ester resins, vinyl acetate resins, carbonate-type resins, polycarbonate-type resins, styrene-type resins, ethylene-type resins, polyethylene-type resins, propylene-type resins, polypropylene-type resins, urethane-type resins, polyurethane-type resins, polyester-type resins and copolymer resins thereof, but acrylic resins are preferred.

[0025] As resin fine particles, for example, a resin having a glass transition temperature (Tg) in the range of 0°C to 200°C is used. More preferably, the glass transition temperature (Tg) is 20°C to 180°C, and even more preferably, 30°C to 150°C.

[0026] For example, commercially available emulsions may be used. Examples of commercially available emulsions include "Superflex® 870" (Tg: 71℃) and "Superflex® 150" (Tg: 40℃) from Daiichi Kogyo Seiyaku Co., Ltd., "Movinyl® 6760" (Tg: -28℃) and "Movinyl® DM774" (Tg: 33℃) from Japan Coating Resin Co., Ltd., "Polyzol® AP-3270N" (Tg: 27℃) from Showa Denko K.K., and "Hyloth-X® KE-1062" (Tg: 112℃) and "Hyloth-X® QE-1042" (Tg: 69℃) from Seikoh PMC Co., Ltd.

[0027] The average particle size of the resin microparticles is, for example, within the range of 30 nm to 200 nm. The average particle size can be measured as the arithmetic mean using, for example, the LB-550 dynamic light scattering particle size distribution analyzer manufactured by Horiba, Ltd.

[0028] The content of resin fine particles (R) in the total amount of ink is preferably in the range of 0.1 wt% to 30 wt%, more preferably in the range of 0.5 wt% to 20 wt%, and particularly preferably in the range of 1.0 wt% to 15.0 wt%. In this embodiment, the acrylic resin is contained in the aqueous ink in the range of 4.6 wt% to 6.0 wt%. One type of resin fine particle may be used alone, or two or more types may be used in combination.

[0029] The colorant is a pigment that can be dispersed in water, for example, by a pigment dispersion resin (resin dispersant). Examples of colorants include carbon black, inorganic pigments, and organic pigments. Examples of carbon black include furnace black, lamp black, acetylene black, and channel black. Examples of inorganic pigments include titanium dioxide, iron oxide-based inorganic pigments, and carbon black-based inorganic pigments. Examples of organic pigments include azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments; polycyclic pigments such as phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments; dye lake pigments such as basic dye-type lake pigments and acid dye-type lake pigments; nitro pigments; nitroso pigments; aniline black daylight fluorescent pigments; and the like. In this embodiment, carbon ink is used as an aqueous ink containing carbon black.

[0030] The solid content of the colorant in the total ink is not particularly limited and can be appropriately determined, for example, based on the desired optical density or saturation. The solid content of the colorant is preferably in the range of 0.1 wt% to 20.0 wt%, and more preferably in the range of 1.0 wt% to 15.0 wt%. In this embodiment, carbon black is included in the aqueous ink in the range of 4.0 wt% to 6.0 wt%. The solid content of the colorant is the weight of the pigment only and does not include the weight of resin fine particles. One type of colorant may be used alone, or two or more types may be used in combination.

[0031] There are no particular limitations on the water-soluble organic solvent; any solvent can be used. Examples of water-soluble organic solvents include propylene glycol, ethylene glycol, 1,2-butanediol, propylene glycol monobutyl ether, dipropylene glycol monopropyl ether, triethylene glycol monobutyl ether, 1,2-hexanediol, 1,6-hexanediol, etc., with glycol ethers having a propylene oxide group being preferred. Examples of other organic solvents include alkyl alcohols having 1 to 4 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl alcohol; alkylene glycols containing 2 to 6 carbon atoms in the alkylene group, such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol; glycerin, ethylene glycol monomethyl (or ethyl, propyl, butyl) ether, diethylene glycol monomethyl (or ethyl, propyl, butyl) ether Lower alkyl ethers of alkylene glycols such as (I) ether, triethylene glycol monomethyl (or ethyl, propyl, butyl, hexyl) ether, tetraethylene glycol monomethyl (or ethyl, propyl, butyl, hexyl) ether, propylene glycol monomethyl (or ethyl, propyl, butyl) ether, dipropylene glycol monomethyl (or ethyl, propyl, butyl) ether, tripropylene glycol monomethyl (or ethyl, propyl, butyl) ether, and tetrapropylene glycol monomethyl (or ethyl) ether; also include N-methyl-2-pyrrolidone, 2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone.

[0032] The content of water-soluble organic solvent in the total amount of ink is preferably 50 wt% or less, and more preferably 40 wt% or less, of the total amount of ink, with the organic solvent existing as a liquid on its own at 25°C. Furthermore, the mass ratio of water-soluble organic solvent to solid content in the ink (water-soluble organic solvent / solid content) is preferably 1.0 or more in order to avoid contact between the particles constituting the solid content. More preferably, the mass ratio of water-soluble organic solvent to solid content in the ink (water-soluble organic solvent / solid content) is 2.0 or more. The solid content includes at least pigment. In this embodiment, the solid content includes pigment and resin microparticles. The water-soluble organic solvent is preferably a solvent whose evaporation rate at 20°C is less than or equal to the evaporation rate of water. For example, since the saturated vapor pressure of water at 20°C is approximately 2300 Pa, from the viewpoint of suppressing the evaporation rate of the ink to 1 / 10 of the evaporation rate of water, the saturated vapor pressure of the water-soluble organic solvent is preferably 230 Pa or less. Furthermore, from the viewpoint of suppressing the evaporation rate of ink to 1 / 100th of the evaporation rate of water, it is more preferable that the saturated vapor pressure of the water-soluble organic solvent be 20 Pa or less. However, the saturated vapor pressure of the water-soluble organic solvent may be 230 Pa or more. In this case, the ink dries more easily.

[0033] The water is preferably deionized water or pure water. The water content in the total ink is preferably in the range of 15 wt% to 95 wt%, and more preferably in the range of 25 wt% to 85 wt%. The water content may be, for example, the remainder of the other components.

[0034] Examples of additives include surfactants, pH adjusters, viscosity modifiers, surface tension modifiers, preservatives, fungicides, leveling agents, defoamers, light stabilizers, antioxidants, nozzle drying inhibitors, polymer components such as emulsions, and dyes. Surfactants may further include cationic surfactants, anionic surfactants, or nonionic surfactants. These surfactants may be commercially available products, for example. Examples of commercially available products include "Orphine® E1010," "Orphine® E1006," "Orphine® E1004," "Sylface SAG503A," and "Sylface SAG002" manufactured by Nisshin Chemical Industry Co., Ltd. The surfactant content in the total ink is, for example, 5 wt% or less, 3 wt% or less, or 0.1 wt% to 2 wt%. Examples of viscosity modifiers include polyvinyl alcohol, cellulose, and water-soluble resins.

[0035] Ink can be prepared, for example, by uniformly mixing resin fine particles, a colorant, a water-soluble organic solvent, water, and other additives as needed, using a conventionally known method, and then removing insoluble materials with a filter or the like.

[0036] [Cap 71] As shown in Figure 3, the cap 71 is positioned to the right of the platen 28. The cap 71 is located between the guide rails 43 and 44 in the front-to-back direction. The cap 71 is cup-shaped and opens upwards. As shown in Figure 4, the cap 71 is movable vertically by a cap drive motor 104 (see Figure 10). The cap 71 is made of an elastic material such as rubber. As shown by the dashed line in Figure 4, the cap 71 is in close contact with the nozzle surface 33A of the print head 34 at the capping position, covering the openings of all the nozzles 33.

[0037] A waste ink tube 71A is connected to the cap 71. An outlet 80 is formed at the bottom of the cap 71. One end of the waste ink tube 71A is connected to the outlet 80. The internal space of the waste ink tube 71A is open to fluid flow. The other end of the waste ink tube 71A is connected to the waste ink tank 81. A pump 77 is located inside the waste ink tube 71A.

[0038] When the cap 71 is in close contact with the nozzle surface 33A of the print head 34, the pump 77 is driven, the internal space of the cap 71 is depressurized, and ink is discharged from the nozzle 33 of the print head 34. The ink discharged from the print head 34 flows out of the internal space of the cap 71 through the waste ink tube 71A to the waste ink tank 81.

[0039] [Wipe Unit 121] The wipe unit 121 is a device for wiping off ink adhering to the nozzle surface 33A of the print head 34. The wipe unit 121 is a device suitable for wiping off solidified ink D (see Figures 7 and 12) (hereinafter referred to as solidified ink D) which has dried and hardened on the nozzle surface 33A, and high-viscosity ink (hereinafter referred to as high-viscosity ink) which has become highly viscous due to drying, by ejecting ink from multiple nozzles 33. As time passes, the ink adhering to the nozzle surface 33A dries further, becomes more viscous, and is more likely to harden on the nozzle surface 33A. The state in which ink hardens on the nozzle surface 33A means that the ink has substantially solidified and has almost lost its fluidity as a liquid. In other words, the state in which ink hardens on the nozzle surface 33A means, for example, that the viscosity of the ink has become 30,000 mPa·s or more.

[0040] The wipe unit 121, as shown in Figures 3 and 5, includes a storage tank 122, a first discharge section 123, a first support section 124, a first wiper 125, a second discharge section 126, a second support section 127, a second wiper 128, and a biasing member 129.

[0041] The storage tank 122 is located to the right of the cap 71 (see Figure 3). The storage tank 122 is located between the guide rails 43 and 44 in the front-rear direction. The storage tank 122 is supported by a frame provided inside the housing 13 so as to be movable in the vertical direction. The storage tank 122 has a box shape that opens upward. Inside the storage tank 122, the first discharge section 123, the first wiper 125, the second discharge section 126, and the second wiper 128 are arranged in this order from right to left in the left-right direction. The left-right direction is an example of the first direction.

[0042] The first discharge section 123 is fixed to the right of the center in the left-right direction on the bottom surface 122A of the storage tank 122. The first discharge section 123 has a flat plate shape that extends in the front-rear and up-down directions from the bottom surface 122A of the storage tank 122. The first discharge section 123 has a first cleaning fluid passage 123A that extends in the up-down direction. The first cleaning fluid passage 123A is rectangular in shape, and when viewed from the up-down direction, it is longer in the front-rear direction than in the left-right direction (see Figure 3). Cleaning fluid can flow through the first cleaning fluid passage 123A. The first cleaning fluid passage 123A has a first discharge port 123B that opens at the upper end of the first discharge section 123. The first discharge port 123B is located below the upper end of the storage tank 122 in the up-down direction. The first discharge port 123B is rectangular in shape, and when viewed from the up-down direction, it is longer in the front-rear direction than in the left-right direction (see Figure 3). The first cleaning fluid channel 123A has a first inlet 123C that opens at the lower end of the first discharge section 123. The first inlet 123C is rectangular in shape, and is longer in the front-to-back direction than in the left-to-right direction when viewed from above (see Figure 3). The first discharge section 123 is an example of a discharge section.

[0043] The first support portion 124 is fixed to the bottom surface 122A of the storage tank 122. The first support portion 124 is adjacent to the left of the first discharge portion 123. In other words, the first discharge portion 123 is adjacent to the right of the first support portion 124. The first support portion 124 has a first wiper housing space 124A that opens upward. The first wiper housing space 124A is a roughly rectangular parallelepiped shape that is longer in the front-to-back direction than in the left-to-right direction. The upper part of the first wiper housing space 124A widens to the left as it goes upward, as the upper left end of the first support portion 124 bends so that it extends to the left as it goes upward. The first support portion 124 is an example of a support portion.

[0044] The first wiper 125 is supported by the first support portion 124. The first wiper 125 is adjacent to the left of the first discharge portion 123 via the first support portion 124. In other words, the first discharge portion 123 is adjacent to the right of the first wiper 125 via the first support portion 124. The first wiper 125 has a flat plate shape that extends in the front-rear and up-down directions. Specifically, the first wiper 125 has a base portion 125A and a tip portion 125B.

[0045] The base end portion 125A is fixed to the first support portion 124 by being press-fitted into the first wiper housing space 124A. This positions the base end portion 125A in the left-right direction. The thickness L1 of the base end portion 125A in the left-right direction is, for example, 1.5 mm. The length L2 of the base end portion 125A in the vertical direction is, for example, within the range of 4 mm to 8 mm.

[0046] The tip portion 125B is the part that extends upward from the upper end of the base portion 125A. The tip portion 125B protrudes above the upper end of the storage tank 122 in the vertical direction. The vertical length L3 of the tip portion 125B is, for example, within the range of 3 mm to 7 mm. The vertical direction is an example of the extension direction. The horizontal thickness L4 of the tip portion 125B is smaller than the horizontal thickness L1 of the base portion 125A. The thickness L4 of the tip portion 125B is, for example, 0.8 mm. The tip of the tip portion 125B has a tapered shape, with the thickness decreasing towards the top.

[0047] The entire first wiper 125 is formed of an elastomer. The first wiper 125 only needs to contain an elastomer; for example, only the tip portion 125B may be formed of an elastomer. Examples of elastomers include rubber. The hardness of the first wiper 125 is 45 degrees or higher. Preferably, the hardness of the first wiper 125 is in the range of 45 degrees to 90 degrees. The load of the first wiper 125 per unit length in the front-rear direction is in the range of 0.25 gf / mm to 0.5 gf / mm.

[0048] The second discharge section 126 is located to the left of the first support section 124, with a gap between them. The second discharge section 126 is fixed to the bottom surface 122A of the storage tank 122. The second discharge section 126 has a flat plate shape that extends from the bottom surface 122A of the storage tank 122 in the front-rear and up-down directions. The second discharge section 126 has a second cleaning fluid passage 126A that extends in the up-down direction. The second cleaning fluid passage 126A is rectangular in shape, and when viewed from the up-down direction, it is longer in the front-rear direction than in the left-right direction (see Figure 3). Cleaning fluid can flow through the second cleaning fluid passage 126A. The second cleaning fluid passage 126A has a second discharge port 126B that opens at the upper end of the second discharge section 126. The second discharge port 126B is rectangular in shape, and when viewed from the front-rear direction, it is longer in the front-rear direction than in the left-right direction (see Figure 3). The second discharge port 126B is located below the upper end of the storage tank 122 in the vertical direction. The second washing fluid flow path 126A has a second inlet 126C that opens at the lower end of the second discharge section 126. The second inlet 126C is rectangular in shape, and is longer in the front-to-back direction than in the left-to-right direction when viewed from the vertical direction. The second discharge section 126 may be omitted.

[0049] The second support section 127 is located adjacent to the left of the second discharge section 126. As shown in Figures 5 and 6, the second support section 127 has a support body 141 and a pair of bosses 142. The support body 141 is box-shaped and has a second wiper housing space 161 that opens upward. Specifically, the support body 141 has a front support wall 141A, a rear support wall 141B, a right support wall 141C, a left support wall 141D, and a lower support wall 141E.

[0050] The front support wall 141A has a front inner surface 191 that defines the front end of the second wiper housing space 161. The rear support wall 141B has a rear inner surface 192 that defines the rear end of the second wiper housing space 161. The right support wall 141C has a right inner surface 193 that defines the right end of the second wiper housing space 161. The right inner surface 193 is slightly inclined with respect to the vertical direction so as it extends slightly to the left as it goes upward. The left support wall 141D extends upward more than the front support wall 141A, the rear support wall 141B, and the right support wall 141C. The left support wall 141D has a left inner surface 194 that defines the left end of the second wiper housing space 161. The left inner surface 194 is parallel to the right inner surface 193. The left inner surface 194 is slightly inclined with respect to the vertical direction so as it extends slightly to the left as it goes upward. The upper end of the left inner surface 194 is located above the upper end of the storage tank 122. The lower support wall 141E has a lower inner surface 195 that defines the lower end of the second wiper housing space 161. The lower inner surface 195 is slightly inclined with respect to the left-right direction, slightly upward as it moves to the right. The lower inner surface 195 is perpendicular to the right inner surface 193 and the left inner surface 194.

[0051] The pair of bosses 142 includes a front boss 142A extending forward from the outer surface of the front support wall 141A, and a rear boss 142B extending backward from the outer surface of the rear support wall 141B. The front boss 142A is located at the upper end of the outer surface of the front support wall 141A. The front boss 142A has a rectangular prism shape. However, the front boss 142A may also be cylindrical. The front boss 142A is inserted into a front through-hole 201 that penetrates the front wall of the storage tank 122 in the front-rear direction, so as to be movable in the vertical direction. The front through-hole 201 extends vertically from the upper end of the storage tank 122 to approximately the center of the storage tank 122 in the vertical direction. The upper end of the front through-hole 201 opens upward. The length of the front through-hole 201 in the left-right direction is slightly longer than the length of the front boss 142A in the left-right direction.

[0052] The rear boss 142B is located at the upper end of the outer surface of the rear support wall 141B. The rear boss 142B has a rectangular prism shape. However, the rear boss 142B may also be cylindrical. The rear boss 142B is inserted into a rear through-hole 202 that penetrates the rear wall of the storage tank 122 in the front-rear direction, so as to be movable in the vertical direction. The rear through-hole 202 extends vertically from the upper end of the storage tank 122 to approximately the center of the storage tank 122 in the vertical direction. The upper end of the rear through-hole 202 opens upward. The length of the rear through-hole 202 in the left-right direction is slightly longer than the length of the rear boss 142B in the left-right direction. As a result, the second support portion 127 is positioned in the left-right direction by the inner surface of the front through-hole 201 and the inner surface of the rear through-hole 202.

[0053] Alternatively, instead of the front through-hole 201 and the rear through-hole 202, a pair of bosses 142 may be inserted vertically into grooves extending vertically along the inner surfaces of the front and rear walls of the storage tank 122.

[0054] The second wiper 128 is supported by the second support portion 127. The second wiper 128 has a rectangular parallelepiped shape that is longer in the front-to-back direction than in the left-to-right direction. The shape and size of the upper and lower surfaces of the second wiper 128 are approximately equal to the shape and size of the lower inner surface 195 of the lower support wall 141E. The shape and size of the left and right surfaces of the second wiper 128 are approximately equal to the shape and size of the left inner surface 194 of the left support wall 141D.

[0055] The second wiper 128 is fixed to the second support portion 127 by being press-fitted into the second wiper housing space 161. The entire left surface of the second wiper 128 is in contact with the left inner surface 194 of the left support wall 141D. As a result, the second wiper 128 is fixed to the second support portion 127 such that its right corner 211 (see Figure 7) is located at the upper end. In other words, the second wiper 128 is fixed to the second support portion 127 in a position where its upper surface is slightly inclined relative to the nozzle surface 33A, starting from a position where its upper surface is parallel to the nozzle surface 33A, and then slightly downward as it moves to the left. To put it another way, the upper surface of the second wiper 128 is fixed to the second support portion 127 in a position where it faces diagonally upward to the left. The upper surface of the second wiper 128 is flush with the upper surface of the second support portion 127. When the upper surface of the second wiper 128 is positioned parallel to the nozzle surface 33A, that is, when the upper surface of the second wiper 128 is positioned perpendicular to the nozzle surface 33A, the vertical length L5 between the upper and lower surfaces of the second wiper 128 is, for example, 10 mm.

[0056] The entire second wiper 128 is formed of an elastomer. The second wiper 128 only needs to contain an elastomer; for example, only the upper part of the second wiper 128 may be formed of an elastomer. Examples of elastomers include rubber. The hardness of the second wiper 128 is higher than that of the first wiper 125. In other words, the hardness of the first wiper 125 is lower than that of the second wiper 128. The hardness of the second wiper 128 is, for example, 60 degrees or higher. Preferably, the hardness of the second wiper 128 is, for example, in the range of 90 degrees to 100 degrees. The load on the second wiper 128 per unit length in the front-rear direction is, for example, in the range of 0.25 gf / mm to 4.0 gf / mm.

[0057] The biasing member 129 supports the second support portion 127. The biasing member 129 is a coil spring that can be compressed in the vertical direction. The upper end of the biasing member 129 is attached to the lower surface of the second support portion 127. The lower end of the biasing member 129 is attached to the bottom surface 122A of the storage tank 122. The biasing member 129 supports the second support portion 127 such that the upper end of the second wiper 128 is located above the upper end of the storage tank 122 in the vertical direction. The biasing member 129 supports the second support portion 127 such that the upper end of the second wiper 128 is located below the upper end of the first wiper 125 in the vertical direction.

[0058] The storage tank 122 of the wipe unit 121 is movable vertically between a retracted position and a contact position by the wipe drive motor 105 (see Figure 10). The retracted position is the position where the storage tank 122 has been lowered so that the upper ends of the first wiper 125 and the second wiper 128 are located below the nozzle surface 33A in the vertical direction. In other words, the retracted position is the position where the storage tank 122 has been lowered so that the first wiper 125 and the second wiper 128 do not come into contact with the nozzle surface 33A when the carriage 40 on which the print head 34 is mounted moves horizontally. In Figure 5, the retracted position is shown by a solid line. The storage tank 122 is in the retracted position when an image is recorded on the sheet 6.

[0059] The contact position is the position where the storage tank 122 has risen so that the upper ends of the first wiper 125 and the second wiper 128 are positioned above the nozzle surface 33A in the vertical direction. In other words, the contact position is the position where the storage tank 122 has risen so that the first wiper 125 and the second wiper 128 come into contact with the nozzle surface 33A when the carriage 40, on which the print head 34 is mounted, moves in the left-right direction. The storage tank 122 is located in the contact position during the wiping process described later. In Figure 5, the contact position is indicated by dashed lines.

[0060] The first wiper 125 is designed such that when it contacts the nozzle surface 33A at the contact position, the force P (see Figure 12) acting from the nozzle surface 33A satisfies the following equation 1. That is, the first wiper 125 is designed so that the force P calculated by the following equation is within the range of 0.05 N or more and 0.5 N or less.

number

[0061] y is the displacement of the first wiper 125 (mm) (see Figure 12). L is the length L3 (mm) of the tip portion 125B (see Figure 5). A is the cross-sectional area (mm) of the tip portion 125B. 2 E is the Young's modulus (MPa) of the tip 125B. G is the shear modulus (MPa) of the tip 125B. I is the second moment of area (mm) of the tip 125B. 4 )

[0062] The wiping lateral load F1 of the second wiper 128 is set to be greater than the sum of the adhesion force F2 and the maximum static friction force F3. The wiping lateral load F1 is the force exerted when the second wiper 128 at the contact position wipes away the fixed ink D, as shown in Figure 7. In this embodiment, the wiping lateral load F1 is the force exerted when the second wiper 128 is biased upward by the biasing member 129 and presses the fixed ink D to the right as the carriage 40 moves to the left from the standby position to the capping position. The wiping lateral load F1 is the force per unit length in the front-rear direction of the second wiper 128.

[0063] The adhesive force F2 is the force with which the fixed ink D adheres to the nozzle surface 33A per unit area. In other words, the adhesive force F2 is the force required to detach the fixed ink D per unit area from the nozzle surface 33A. The adhesive force F2 is, for example, 0.101 N / mm 2 That is the case.

[0064] The maximum static friction force F3 is the maximum static friction force per unit area between the solid ink D and the nozzle surface 33A, assuming that when the second wiper 128 presses the solid ink D to the right, the solid ink D cannot be moved to the right and remains on the nozzle surface 33A, while the right corner 211 of the second wiper 128 rides up onto the surface of the solid ink D opposite to the nozzle surface 33A. The maximum static friction force F3 is, for example, 0.425 N / mm². 2 The right corner 211 of the second wiper 128 is an example of one end of the second wiper in the first direction.

[0065] In this embodiment, the wiping lateral load F1 is preferably set to 0.073 N / mm or more. More preferably, the wiping lateral load F1 is set within the range of 0.073 N / mm or more and 0.770 N / mm or less.

[0066] The wiping lateral load F1 was measured by creating a model, for example, as shown in Figure 8. Specifically, first, a carbon film 222 was formed on a PTFE plate 221 made of fluororesin, and the PTFE plate 221 with the carbon film 222 formed on it was fixed to a trolley 223. The thickness of the carbon film 222 was 0.1 mm. Next, a wiper 226 identical to the second wiper 128 was fixed to a support base 225 fixed to a tension gauge 224, and the wiper 226 was pressed against the upper surface of the PTFE plate 221. The pressing load of the second wiper 128 against the PTFE plate 221 was controlled by the tension gauge 224 so that when the second wiper 128 actually contacts the nozzle surface 33A, the force was the same as the biasing force of the biasing member 129 acting on the nozzle surface 33A via the second wiper 128. Next, the digital force gauge 228, which is fixed to the robot cylinder 227, and the trolley 223 were connected by a wire 229.

[0067] Subsequently, the robot cylinder 227 moved the digital force gauge 228 away from the trolley 223, thereby pulling the trolley 223 with the wire 229. The movement speed of the digital force gauge 228 was set to the same speed at which the print head 34 actually moves to the left from the standby position to the capping position with the nozzle surface 33A in contact with the second wiper 128. For example, the movement speed of the digital force gauge 228 is 1 mm / s.

[0068] Finally, the peeling load when the wiper 226 contacts the carbon film 222 and peels it off, and the sliding load when the wiper 226 slides against the PTFE plate 221 were measured using a digital force gauge 228. The value obtained by subtracting the sliding load from the peeling load is the wiping lateral load F1.

[0069] As shown in Figures 5 and 9, the first discharge section 123 and the second discharge section 126 of the wipe unit 121 are connected to the cleaning fluid tank 17 via a supply pipe 19. The cleaning fluid tank 17 is a tank that stores cleaning fluid. For example, water is used as the cleaning fluid. One end of the supply pipe 19 is connected to the cleaning fluid tank 17. The other end of the supply pipe 19 is branched into two. The other end of the supply pipe 19 is connected to the first inlet 123C and the second inlet 126C through two circular lower insertion holes 150 that penetrate the lower wall of the storage tank 122. A supply pump 15 is located in the supply pipe 19.

[0070] When the supply pump 15 is driven, the cleaning fluid stored in the cleaning fluid tank 17 is supplied through the supply pipe 19 from the first inlet 123C to the first cleaning fluid passage 123A and from the second inlet 126C to the second cleaning fluid passage 126A. The cleaning fluid supplied to the first cleaning fluid passage 123A and the second cleaning fluid passage 126A is discharged upward from the first outlet 123B and the second outlet 126B. The driving force of the supply pump 15 is set so that the cleaning fluid discharged upward from the first outlet 123B and the second outlet 126B rises to at least the height of the nozzle surface 33A in the vertical direction. For example, the discharge rate of cleaning fluid from the first outlet 123B and the second outlet 126B is 0.076 ml / s.

[0071] The cleaning fluid discharged upward from the first outlet 123B and the second outlet 126B rises to at least the height of the nozzle surface 33A in the vertical direction, and then falls due to gravity and is received in the storage tank 122.

[0072] The storage tank 122 of the wipe unit 121 is connected to the waste ink tank 81 via a waste liquid pipe 20. One end of the waste liquid pipe 20 is connected to the waste ink tank 81. The other end of the waste liquid pipe 20 is connected to the inside of the storage tank through a circular left insertion hole 151 that penetrates the left wall of the storage tank 122. A waste liquid pump 16 is located on the waste liquid pipe 20. When the waste liquid pump 16 is driven, the cleaning liquid in the storage tank 122 is discharged through the waste liquid pipe 20 to the waste ink tank 81.

[0073] [Controller 130 and memory 140] The controller 130 controls various operations of the printer 10. As shown in Figure 10, the controller 130 includes a CPU 131 and an ASIC 135. The memory 140 includes a ROM 132, a RAM 133, and an EEPROM 134. The CPU 131, ASIC 135, ROM 132, RAM 133, and EEPROM 134 are connected by an internal bus 137.

[0074] ROM132 stores programs that the CPU131 uses to control various operations. RAM133 is used as a temporary storage area for data and signals used by the CPU131 when executing the above programs, or as a working area for data processing. EEPROM134 stores settings and flags that should be retained even after the power is turned off.

[0075] The ASIC135 is connected to a transport motor 101, a feeding motor 102, a carriage drive motor 181, a cap drive motor 104, and a wipe drive motor 105. The ASIC135 incorporates drive circuits to control each motor. The CPU 131 outputs drive signals to the corresponding drive circuits for each motor to rotate them. The drive circuits output a drive current to the corresponding motor according to the drive signal received from the CPU 131. This causes the corresponding motor to rotate. In other words, the controller 130 controls the feeding motor 102 to feed the sheets 6 into the transport path 37. The controller 130 also controls the transport motor 101 to drive the transport rollers 26 and discharge rollers 27 to transport the sheets 6. The controller 130 also controls the carriage drive motor 181 to move the carriage 40 in the left-right direction. The controller 130 also controls the cap drive motor 104 to move the caps 71 in the up-down direction. Furthermore, the controller 130 controls the wipe drive motor 105 to move the storage tank 122 in the vertical direction.

[0076] A piezoelectric element 45 is connected to the ASIC135. The piezoelectric element 45 operates by being powered by the controller 130 via an IC (not shown). The controller 130 controls the power supply to the piezoelectric element 45, selectively ejecting ink droplets from multiple nozzles 33.

[0077] When recording an image on sheet 6, the controller 130 alternately performs the transport process and the printing process. The transport process is the process of transporting sheet 6 by a predetermined amount of line breaks by driving the transport rollers 26 and discharge rollers 27. The controller 130 executes the transport process by controlling the transport motor 101. The printing process is the process of moving the carriage 40 in the left-right direction while controlling the power supply to the piezoelectric element 45 to eject ink droplets from the nozzles 33 to the print head 34.

[0078] The controller 130 stops the sheet 6 after the transport process is completed. The controller 130 performs the printing process while the sheet 6 is stopped. In other words, during the printing process, the controller 130 performs one pass in which ink droplets are ejected from the nozzle 33 while moving the carriage 40 to the right or left. This performs one pass of image recording on the sheet 6. By repeatedly performing the transport process and the printing process alternately, the controller 130 can record images on the entire image-recordable area of ​​the sheet 6. In other words, the controller 130 records images on one sheet 6 in multiple passes. The controller 130 raises the cap 71 with the cap drive motor 104, bringing it into close contact with the nozzle surface 33A of the print head 34 at the capping position. The controller 130 lowers the cap 71 with the cap drive motor 104, separating the cap 71 from the nozzle surface 33A.

[0079] A supply pump 15 is connected to ASIC135. ASIC135 controls the operation of supply pump 15. A pump 77 is connected to ASIC135. ASIC135 controls the operation of pump 77. A waste liquid pump 16 is connected to ASIC135. ASIC135 controls the operation of waste liquid pump 16.

[0080] The controller 130 performs maintenance operations, including purging, wiping, and flushing. Maintenance operations are performed, for example, when the elapsed time t since the last wiping operation reaches an initial elapsed time t0 stored in the EEPROM 134. Maintenance operations may also be performed at other times, such as when the printer 10 is powered on or when the cartridge 70 is replaced. Maintenance operations may also be performed immediately after the completion of a print operation. In the maintenance operations, purging, wiping, and flushing are performed in order.

[0081] The purging process involves covering the nozzle 33 with the cap 71 and then using the pump 77 to draw ink from the nozzle 33. During the purging process, the inside of the cap 71 becomes negatively pressurized by the operation of the pump 77, and foreign matter is drawn out of the nozzle 33 along with the ink. The wiping process involves wiping the nozzle surface 33A of the print head 34 with the first wiper 125 and the second wiper 128. Details of the wiping process will be described later. The flushing process involves ejecting ink towards the cap 71.

[0082] [Maintenance processing] Next, with reference to Figure 11, the maintenance process by the controller 130 will be explained. In the initial state, the cap 71 is in close contact with the nozzle surface 33 of the print head 34. The wipe unit 121 is in the retracted position.

[0083] The controller 130 determines whether the elapsed time t since the last wiping process has reached the initial elapsed time t0 stored in the EEPROM 134 (step S1). If the controller 130 determines that the elapsed time t has not reached the initial elapsed time t0 (step S1; No), it waits until the elapsed time t reaches the initial elapsed time t0. If the controller 130 determines that the elapsed time t has reached the initial elapsed time t0 (step S1; Yes), it drives the pump 77 for a predetermined time to perform the purging process (step S1). The controller 130 drives the cap driving motor 104 to lower the cap 71 (step S3). This causes the cap 71 to move away from the nozzle surface 33. Next, the wiping process is performed.

[0084] The controller 130 drives the carriage drive motor 181 to move the carriage 40 to the right from the capping position to the standby position (step S4). The controller 130 drives the wipe drive motor 105 to raise the storage tank 122 of the wipe unit 121 from the retracted position to the contact position (step S5). The controller 130 drives the supply pump 15 to continue supplying the cleaning fluid stored in the cleaning fluid tank 17 to the first cleaning fluid passage 123A of the first discharge section 123 and the second cleaning fluid passage 126A of the second discharge section 126 via the supply pipe 19 (step S6). As a result, the cleaning fluid continues to be discharged upward from the first discharge port 123B of the first cleaning fluid passage 123A and the second discharge port 126B of the second cleaning fluid passage 126A. The cleaning fluid discharged from the first outlet 123B and the second outlet 126B rises vertically to at least the height of the nozzle surface 33A, and then falls due to gravity and is received in the storage tank 122.

[0085] The controller 130 drives the carriage drive motor 181 to move the carriage 40 from the standby position to the capping position to the left (step S7). As a result, while the carriage 40 moves to the left above the storage tank 122, the cleaning fluid continuously discharged from the first discharge port 123B comes into contact with the nozzle surface 33A of the print head 34, and subsequently the first wiper 125 comes into contact with the nozzle surface 33A. As a result, as shown in Figure 12, the space between the nozzle surface 33A and the first wiper 125 is filled with cleaning fluid. In this state, the cleaning fluid comes into contact with the fixed ink D and high-viscosity ink adhering to the nozzle surface 33A, and the first wiper 125 presses the fixed ink D and high-viscosity ink to the right. As a result, the fixed ink D deforms and becomes softer, making it easier for the cleaning fluid to penetrate inside, and easier to peel off from the nozzle surface 33A. High-viscosity inks lose viscosity upon contact with cleaning solution, making them more prone to peeling off the nozzle surface 33A.

[0086] Subsequently, the cleaning fluid continuously discharged from the second discharge port 126B comes into contact with the nozzle surface 33A, and then the right corner 211 of the second wiper 128 is biased upward by the biasing member and comes into contact with the nozzle surface 33A. As a result, as shown in Figure 12, the space between the nozzle surface 33A and the second wiper 128 is filled with cleaning fluid. In this state, the cleaning fluid comes into contact again with the solidified ink D and high-viscosity ink adhering to the nozzle surface 33A, and the second wiper 128 presses the solidified ink D and high-viscosity ink to the right.

[0087] In this case, the second wiper 128 cannot move the solidified ink D to the right, and the solidified ink D remains on the nozzle surface 33A, while the right corner 211 of the second wiper 128 rides up onto the surface of the solidified ink D from the nozzle surface 33A. In this case, the static friction force generated between the solidified ink D and the nozzle surface 33A becomes large, which may make it difficult for the second wiper 128 to wipe the solidified ink D from the nozzle surface 33A. However, since the hardness of the second wiper 128 is higher than that of the first wiper 125, and the entire left surface of the second wiper 128 is supported by the left inner surface 194 of the left support wall 141D of the second support part 127, the second wiper 128 is less likely to deform and ride up onto the surface of the solidified ink D. For this reason, the second wiper 128 can easily wipe away the solidified ink D and high-viscosity ink from the nozzle surface 33A.

[0088] If the right corner 211 of the second wiper 128 were to ride up onto the surface of the solidified ink D, the static friction force between the solidified ink D and the nozzle surface 33A would increase, making it difficult for the second wiper 128 to adequately wipe away the solidified ink D. In this embodiment, the wiping lateral load F1 of the second wiper 128 is greater than the sum of the adhesion force F2 of the solidified ink D to the nozzle surface 33A per unit area and the maximum static friction force F3 generated between the solidified ink D and the nozzle surface 33A per unit area. Therefore, even if the corner of the second wiper 128 were to ride up onto the surface of the solidified ink D, the solidified ink D adhering to the nozzle surface 33A could be easily wiped away.

[0089] The controller 130 stops the supply of cleaning fluid from the cleaning fluid tank 17 by stopping the supply pump 15 (step S8). This completes the wiping process. The controller 130 drives the cap drive motor 104 to raise the cap 71 and bring it into close contact with the nozzle surface 33A (step S9). The controller 130 controls the power supply to the piezoelectric element 45 to perform a flushing process that ejects ink droplets from the nozzle 33 to the print head 34 (step S10). This completes the maintenance process.

[0090] [Effects of this embodiment] In the above embodiment, during the wiping process, the print head 34 moves to the left relative to the wipe unit 121 while the cleaning solution is supplied to the nozzle surface 33A. At this time, even if the ink adhering to the nozzle surface 33A has dried and become fixed ink D, the fixed ink D is deformed by contact with the cleaning solution and being pressed to the left by the first wiper 125, making it easier for the cleaning solution to penetrate inside and making it softer. In this state, the second wiper 128 presses the fixed ink D to the left. Therefore, even if the ink adhering to the nozzle surface has dried and become fixed ink D, the second wiper 128 can easily wipe the fixed ink D from the nozzle surface 33A. Similarly, even if the ink adhering to the nozzle surface 33A has dried and become high-viscosity ink, the viscosity of the high-viscosity ink decreases when the cleaning solution comes into contact with it, making it easier to peel off the nozzle surface 33A. Therefore, the first wiper 125 and the second wiper 128 can easily wipe away high-viscosity ink from the nozzle surface 33A.

[0091] In the above embodiment, the first discharge section 123 is adjacent to the right of the first wiper 125 via the first support section 124. During the wiping process, cleaning fluid is continuously discharged from the first discharge port 123B onto the nozzle surface 33A, resulting in a state where the space between the nozzle surface 33A and the first wiper 125 is filled with cleaning fluid. As a result, the cleaning fluid easily comes into contact with the fixed ink D and high-viscosity ink adhering to the nozzle surface 33A, making it easier for the fixed ink D and high-viscosity ink to peel off from the nozzle surface 33A.

[0092] In the above embodiment, the hardness of the first wiper 125 is lower than that of the second wiper 128, so that the nozzle surface 33A is not damaged by the first wiper 125.

[0093] In the above embodiment, the hardness of the second wiper 128 is 60 degrees or higher, so the second wiper 128 is less likely to deform when pressing the fixed ink D and high-viscosity ink to the right. For this reason, the second wiper 128 can easily wipe away the fixed ink D and high-viscosity ink from the nozzle surface 33A.

[0094] In the above embodiment, the load of the second wiper 128 is within the range of 0.25 gf / mm to 4.0 gf / mm. By having a load of 4.0 gf / mm or less for the second wiper 128, damage to the nozzle surface 33A by the second wiper 128 is suppressed. By having a load of 0.25 gf / mm or more for the second wiper 128, the second wiper 128 can easily wipe away the fixed ink D and high-viscosity ink from the nozzle surface 33A.

[0095] In the above embodiment, the entirety of the first wiper 125 and the second wiper 128 is formed of elastomer. Therefore, the first wiper 125 and the second wiper 128 adhere easily to the nozzle surface 33A, making it easy to wipe away the solidified ink D and high-viscosity ink from the nozzle surface 33A.

[0096] In the above embodiment, the ink discharged from the multiple nozzles 33 is an aqueous ink containing at least a water-soluble organic solvent and water. The cleaning solution discharged onto the nozzle surface 33A from the first discharge port 123B and the second discharge port 126B is water. Therefore, because the ink and the cleaning solution have high compatibility, when the cleaning solution comes into contact with the fixed ink D and high viscosity ink adhering to the nozzle surface 33A, the fixed ink D and high viscosity ink dissolve easily in the cleaning solution. For this reason, the fixed ink D and high viscosity ink are easily peeled off from the nozzle surface 33A.

[0097] In the above embodiment, even if the viscosity of the aqueous ink adhering to the nozzle surface 33A changes within a range of at least 1 mPa·s to 100 mPa·s due to drying, the first wiper 125 and the second wiper 128 can easily wipe the aqueous ink adhering to the nozzle surface 33A from the nozzle surface 33A.

[0098] In the above embodiment, even if the aqueous ink adhering to the nozzle surface 33A becomes a high-viscosity ink with a viscosity of at least 1000 mPa·s or more due to drying, the first wiper and the second wiper can easily wipe the high-viscosity ink from the nozzle surface 33A.

[0099] In the above embodiment, the aqueous ink discharged from the multiple nozzles 33 contains an acrylic resin in the range of 4.0 wt% to 6.0 wt% and carbon black in the range of 4.0% to 6.0% by weight. Therefore, the aqueous ink adhering to the nozzle surface 33A tends to dry and become fixed ink D in which the acrylic resin and carbon black are fixed to the nozzle surface 33A, but this fixed ink D can be easily wiped off from the nozzle surface 33A by the second wiper 128.

[0100] In the above embodiment, the wiping lateral load F1 of the second wiper 128 is determined by considering not only the adhesion force F2 of the fixed ink D to the nozzle surface 33A per unit area, but also the maximum static friction force F3 generated between the fixed ink D and the nozzle surface 33A per unit area, assuming that when the second wiper 128 presses the fixed ink D to the right, the fixed ink D cannot be moved to the right and remains on the nozzle surface 33A, and the right corner 211 of the second wiper 128 rides up onto the surface of the fixed ink D opposite to the nozzle surface 33A. Therefore, even if the right corner 211 of the second wiper 128 rides up onto the surface of the fixed ink D, the fixed ink D adhering to the nozzle surface 33A can be easily wiped away.

[0101] In the above embodiment, the aqueous ink discharged from the multiple nozzles 33 is carbon ink containing carbon black. The hardness of the second wiper 128 is 90 degrees or higher. The wiping lateral load F1 of the second wiper 128 is set to 0.073 N / mm or higher. Therefore, even if the carbon ink adhering to the nozzle surface 33A dries and becomes fixed ink D on the nozzle surface 33A, the second wiper 128 can easily wipe away the fixed ink D from the nozzle surface 33A.

[0102] In the above embodiment, the vertical length L3 of the tip portion 125B of the first wiper 125 is within the range of 3 mm to 7 mm, so that sufficient pressing force is ensured for the first wiper 125 to press the nozzle surface 33A to the right. Therefore, even if the aqueous ink adhering to the nozzle surface 33A becomes a high-viscosity ink with a viscosity fluctuating within the range of at least 1000 mPa·s to 10000 mPa·s due to drying, the first wiper 125 can easily wipe the high-viscosity ink from the nozzle surface 33A.

[0103] In the above embodiment, the hardness of the first wiper 125 is within the range of 45 degrees to 90 degrees, so the first wiper 125 is less likely to deform when pressing the high-viscosity ink to the right. Therefore, even if the aqueous ink adhering to the nozzle surface 33A becomes a high-viscosity ink whose viscosity fluctuates within the range of at least 1000 mPa·s to 10000 mPa·s due to drying, the first wiper 125 can easily wipe the high-viscosity ink from the nozzle surface 33A.

[0104] In the above embodiment, the first wiper 125 is designed such that when it contacts the nozzle surface 33A at the contact position, the force P (see Figure 12) acting from the nozzle surface 33A satisfies the following formula 1. Therefore, even if the aqueous ink adhering to the nozzle surface 33A becomes a high-viscosity ink with a viscosity fluctuating within the range of at least 1000 mPa·s to 10000 mPa·s due to drying, the first wiper 125 can easily wipe away the high-viscosity ink from the nozzle surface 33A.

number

[0105] [Differentiation] In the above embodiment, during the wiping process, the nozzle surface 33A was wiped by the first wiper 125 and the second wiper 128 while the carriage 40, on which the print head 34 is mounted, moved to the left relative to the wipe unit 121. However, during the wiping process, the nozzle surface 33A may be wiped by the first wiper 125 and the second wiper 128 while the print head 34 and the wipe unit 121 move relative to each other in the left-right direction. For example, during the wiping process, the nozzle surface 33A may be wiped by the first wiper 125 and the second wiper 128 while the print head 34 moves to the right relative to the wipe unit 121. In this case, the first discharge unit 123, the first wiper 125, the second discharge unit 126, and the second wiper 128 are arranged in this order from left to right in the left-right direction within the storage tank 122. Furthermore, during the wiping process, the carriage 40 equipped with the print head 34 may move to the left, and the wipe unit 121 may move to the right, while the nozzle surface 33A is wiped by the first wiper 125 and the second wiper 128.

[0106] Furthermore, during the wiping process, the wipe unit 121 may move left-right relative to the print head 34 while the nozzle surface 33A is wiped by the first wiper 125 and the second wiper 128. In this case, a moving mechanism is provided to move the storage tank 122 of the wipe unit 121 in the left-right direction. The moving mechanism is not particularly limited as long as it can move the storage tank 122 in the left-right direction. For example, a gear transmission mechanism can be used as the moving mechanism.

[0107] In the above embodiment, the first discharge section 123 was adjacent to the right of the first wiper 125 via the first support section 124, but it may also be positioned at a distance to the right of the first wiper 125.

[0108] In the above embodiment, the first discharge unit 123 and the second discharge unit 126 continuously discharged cleaning fluid onto the nozzle surface 33A during the wiping process, but it is not necessary to continuously discharge cleaning fluid onto the nozzle surface 33A. For example, the first discharge unit 123 and the second discharge unit 126 may intermittently discharge cleaning fluid onto the nozzle surface 33A during the wiping process.

[0109] In the above embodiment, the hardness of the first wiper 125 was lower than that of the second wiper 128, but it may also be higher than that of the second wiper 128.

[0110] In the above embodiment, the hardness of the second wiper 128 was 60 degrees or higher, but it may be less than 60 degrees.

[0111] In the above embodiment, the load of the second wiper 128 was in the range of 0.25 gf / mm to 4.0 gf / mm, but it may be less than 0.25 gf / mm and greater than 4.0 gf / mm.

[0112] In the above embodiment, the first wiper 125 and the second wiper 128 contained an elastomer, but they do not necessarily contain an elastomer.

[0113] In the above embodiment, the ink ejected from the multiple nozzles 33 was an aqueous ink containing at least a water-soluble organic solvent and water, but it is not limited to aqueous ink as long as an image can be recorded on the sheet 6. For example, as the ink ejected from the multiple nozzles 33, a UV ink containing an ultraviolet curing agent that hardens when exposed to ultraviolet light may be used. The ultraviolet curing agent that hardens when exposed to ultraviolet light includes, for example, a photopolymerization initiator and a polymerizable compound.

[0114] A photopolymerization initiator is a water-soluble compound that causes a polymerization reaction of polymerizable compounds by irradiation with ultraviolet light. The photopolymerization initiator has a solubility of 1 wt% or more in water. Solubility can be determined from the number of grams of photopolymerization initiator dissolved in 100 g of water at 25°C. The photopolymerization initiator has an absorption wavelength peak in the range of 350 nm to 400 nm. The absorption wavelength peak can be measured, for example, using a UV3600 ultraviolet-visible-near-infrared spectrophotometer manufactured by Shimadzu Corporation. For example, a measurement cell with a cell length of 10 mm can be used to measure the absorption wavelength peak.

[0115] For example, acylphosphine oxide-based photopolymerization initiators are used. An example of an acylphosphine oxide-based photopolymerization initiator is lithium phenyl-2,4,6-trimethylbenzoylphosphinate (absorption wavelength peak: 380 nm). Examples of other photopolymerization initiators include 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, hydroxyalkylphenone-based initiators, acetophenone-based initiators, benzophenone-based initiators, benzoin-based initiators, benzoin ether-based initiators, aminoalkylphenone-based initiators, xanthone-based initiators, and oxime-based initiators. For example, examples of hydroxyalkylphenone-based initiators include 1-hydroxycyclohexylphenyl ketone and 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one. Examples of acetophenone-based initiators include acetophenone, 2,2-diethoxyacetophenone, and p-dimethylaminoacetophen. Examples of benzophenone-based initiators include benzophenone, 2-chlorobenzophenone, p,p'-dichlorobenzophenone, p,p'-bisdiethylaminobenzophenone, and Michler's ketone. Examples of benzoin-based initiators and benzoin ether-based initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-propyl ether, benzoin isobutyl ether, and benzoin n-butyl ether. The solid content of the photopolymerization initiator in the total amount of ink is preferably in the range of 0.1 wt% to 10.0 wt%, more preferably in the range of 0.5 wt% to 5.0 wt%, and particularly preferably in the range of 0.8 wt% to 2.5 wt%.

[0116] Polymerizable compounds are water-soluble compounds that undergo polymerization reactions in response to photopolymerization initiators irradiated with ultraviolet light. Polymerizable compounds have a solubility in water of 1 wt% or more. Polymerizable compounds have multiple polymerization-reactive functional groups. Polymerization-reactive functional groups are functional groups that can be polymerized. Examples of polymerization-reactive functional groups include acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, and vinyl ether groups. Examples of polymerizable compounds include N,N'-1,2-ethanediylbis{N-[2-(acryloylamino)ethyl]acrylamide}, N,N'-(((2-acrylamide-2((3-(buta-1,3-diene-2-iramino)propoxy-1,3-diyl)bis(oxy))bis(propane-3,1-diyl))diacrylamide, N,N-bis(2-acrylamideethyl)acrylamide, and N,N'-{oxybis(2,1-ethanediyloxy-3,1-propanediyl)}bisacrylamide. The solid content of the polymerizable compound in the total amount of ink is preferably in the range of 1.0 wt% to 40.0 wt%, more preferably in the range of 2.5 wt% to 40.0 wt%, and particularly preferably in the range of 5.0 wt% to 40 wt%.

[0117] When UV ink is used as the ink ejected from multiple nozzles 33, the cleaning solution ejected from the first outlet 123B and the second outlet 126B onto the nozzle surface 33A may contain any of the following: di(propylene glycol) methyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether, diethylene glycol diethyl ether, or triethylene glycol monomethyl ether. In this way, even if the ink ejected from multiple nozzles 33 is UV ink, the compatibility between the UV ink and the cleaning solution is high, so when the cleaning solution comes into contact with the fixed ink D and high viscosity ink adhering to the nozzle surface 33A, the fixed ink D and high viscosity ink dissolve easily in the cleaning solution. For this reason, the fixed ink D and high viscosity ink are easily peeled off from the nozzle surface 33A.

[0118] In the above embodiment, the second wiper 128 was fixed to the second support portion 127 such that the right corner portion 211 was located at the upper end, but it may also be fixed to the second support portion 127 in a position where the upper surface is parallel to the nozzle surface 33A.

[0119] In the above embodiment, the vertical length L3 of the tip portion 125B of the first wiper 125 was within the range of 3 mm to 7 mm, but is not limited to this.

[0120] In the above embodiment, when the upper surface of the second wiper 128 is facing in a direction perpendicular to the nozzle surface 33A, the vertical length L5 between the upper and lower surfaces of the second wiper 128 was 10 mm, but it may be, for example, 0.5 mm or less. The vertical direction is an example of a direction perpendicular to the nozzle surface 33A. In this way, even if the hardness of the second wiper 128 is low, it will be less likely to deform to the left when pressing the nozzle surface 33A to the right. Therefore, even if the hardness of the second wiper 128 is low, the solidified ink D can be easily wiped away. By lowering the hardness of the second wiper 128, damage to the nozzle surface 33A by the second wiper 128 is suppressed. In this case, the front support wall 141A, rear support wall 141B, right support wall 141C, and left support wall 141D of the second support portion 127 may be omitted. In other words, only the lower surface of the second wiper 128 may be fixed to the lower inner surface 195 of the lower support wall 141E of the second support portion 127 by adhesive or the like. Because the length L5 of the second wiper 128 is short, even if the left side of the second wiper 128 is not fixed to the second support portion 127, the second wiper 128 is less likely to deform to the left when pressing the nozzle surface 33A to the right. For this reason, the second wiper 128 can easily wipe away the solidified ink D from the nozzle surface 33A. [Explanation of Symbols]

[0121] 10. Printer (ink ejection device) 33... Nozzle 33A...Nozzle surface 34. Print head (head) 121... Wipe Unit 123...1st discharge part (discharge part) 124...First support part (support part) 125...1st wiper 125A...Proximal end 125B...Tip 128...2nd wiper 171... Belt moving mechanism (moving mechanism) F1... Wipe away lateral load F2... Adhesion F3...Maximum static friction force

Claims

1. A head having a nozzle surface through which the nozzles that eject ink open, A wiping unit for wiping the nozzle surface, It includes a moving mechanism that moves the head and the wipe unit relative to each other in a first direction, The above wipe unit is, The nozzle surface includes a discharge section that releases cleaning fluid, It has a first wiper and a second wiper that contact the nozzle surface, The above-mentioned discharge unit, the above-mentioned first wiper, and the above-mentioned second wiper are arranged in this order in the first direction in an ink ejection device.

2. The ink ejection device according to claim 1, wherein the discharge section is adjacent to the first wiper, and the head and the wipe unit move relative to each other in the first direction while continuously discharging cleaning fluid onto the nozzle surface, thereby filling the space between the nozzle surface and the first wiper with cleaning fluid.

3. The ink ejection device according to claim 1, wherein the hardness of the first wiper is lower than the hardness of the second wiper.

4. The ink ejection device according to claim 3, wherein the hardness of the second wiper is 60 degrees or more.

5. The ink ejection device according to claim 4, wherein the load of the second wiper is within the range of 0.25 gf / mm or more and 4.0 gf / mm or less.

6. The ink dispensing device according to claim 1, wherein the first wiper and the second wiper are elastomers.

7. The ink dispensing device according to claim 1, wherein the ink dispensed from the nozzle has a viscosity that fluctuates within a range of at least 1 mPa·s to 100 mPa·s due to drying while adhering to the nozzle surface.

8. The ink dispensing device according to claim 1, wherein the ink dispensed from the nozzle has a viscosity of at least 1000 mPa·s or more upon drying while adhering to the nozzle surface.

9. The ink ejection device according to claim 7 or 8, wherein the ink ejected from the nozzle further contains an acrylic resin in an amount of 4.0% by weight or more and 6.0% by weight or less, and carbon black in an amount of 4.0% by weight or more and 6.0% by weight or less.

10. The lateral wiping load applied by the second wiper in the first direction to the solidified ink that has dried and hardened on the nozzle surface is, The adhesion force of the above-mentioned fixed ink to the nozzle surface per unit area, The ink ejection device according to claim 1, wherein, assuming that when the second wiper presses the fixed ink in the first direction, the fixed ink remains on the nozzle surface and one end of the second wiper in the first direction moves onto the surface of the fixed ink opposite to the nozzle surface, the force is greater than the sum of the maximum static friction force generated between the fixed ink and the nozzle surface per unit area.

11. The ink ejected from the above nozzle is carbon ink containing carbon black. The hardness of the second wiper described above is within the range of 90 degrees to 100 degrees. The ink ejection device according to claim 10, wherein the above-mentioned lateral wiping load is in the range of 0.073 N / mm or more and 0.770 N / mm or less.

12. The ink ejection device according to claim 1, wherein the length of the second wiper in the direction perpendicular to the nozzle surface is 0.5 mm or less.

13. The wipe unit described above further includes a support portion that supports the first wiper, The first wiper mentioned above is, A base end fixed to the support portion and positioned in the first direction, It has a tip portion that extends from the base portion in an extension direction perpendicular to the nozzle surface, The length of the tip portion in the extension direction is within the range of 3 mm to 7 mm. The ink dispensing device according to claim 1, wherein the ink dispensed from the nozzle has a viscosity that fluctuates within a range of at least 1,000 mPa·s to 10,000 mPa·s due to drying while adhering to the nozzle surface.

14. The ink ejected from the above nozzle has a viscosity that fluctuates within a range of at least 1000 mPa·s to 10000 mPa·s upon drying while adhering to the nozzle surface. The ink ejection device according to claim 1, wherein the hardness of the first wiper is in the range of 45 degrees or more and 90 degrees or less.

15. The ink ejected from the above nozzle has a viscosity that fluctuates within a range of at least 1000 mPa·s to 10000 mPa·s upon drying while adhering to the nozzle surface. The wipe unit described above further includes a support portion that supports the first wiper, The first wiper mentioned above is, A base end fixed to the support portion and positioned in the first direction, It has a tip portion that extends from the base portion in an extension direction perpendicular to the nozzle surface, The hardness of the first wiper described above is within the range of 45 degrees to 90 degrees. The ink ejection device according to claim 1, wherein the force P acting on the first wiper from the nozzle surface when the first wiper contacts the nozzle surface satisfies the following formula 1. [Math 1] y is the displacement of the tip (mm), L is the length of the tip (mm), and A is the cross-sectional area of ​​the tip (mm). ２ ), E is the Young's modulus of elasticity (MPa) of the tip, G is the shear modulus of elasticity of the tip, and I is the second moment of area (mm) of the tip. ４ )

16. The ink ejected from the above nozzle has a viscosity that fluctuates within a range of at least 1000 mPa·s to 10000 mPa·s upon drying while adhering to the nozzle surface. The hardness of the first wiper described above is within the range of 45 degrees to 90 degrees. The hardness of the second wiper described above is higher than that of the first wiper described above. The above wiping lateral load is within the range of 0.073 N / mm to 0.770 N / mm. The ink ejection device according to claim 10, wherein the amount of cleaning water discharged from the above-mentioned discharge section is 0.076 ml / s or more.

17. The ink ejected from the above nozzle is an aqueous ink containing at least a water-soluble organic solvent and water. The ink ejection device according to claim 15, wherein the cleaning liquid discharged from the discharge section to the nozzle surface is water.

18. The ink dispensed from the above nozzle is a UV ink containing an ultraviolet curing agent that hardens upon irradiation with ultraviolet light. The ink ejection device according to claim 15, wherein the cleaning liquid discharged from the discharge section to the nozzle surface comprises any of the following: di(propylene glycol) methyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether, diethylene glycol diethyl ether, and triethylene glycol monomethyl ether.

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