Liquid discharge device

Abstract

To provide a liquid discharge device which can keep a range around a nozzle clean, and of which increase in cost of manufacture is suppressed.SOLUTION: A liquid discharge device comprises: a first discharge part for discharging an ink onto a recording medium; a second discharge part for discharging a pretreatment liquid to a place where the ink is to be discharged; and a third discharge part for discharging a diluent. The diluent is preferably prepared by diluting at least one of the pretreatment liquid and the ink.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a liquid ejection device.

Background Art

[0002] An inkjet printer that directly prints on T-shirts, tote bags, hats, etc., so-called garment printers, is known.

[0003] Patent Document 1 discloses an inkjet recording method including a step of applying a predetermined aqueous ink to form an image and a step of applying a predetermined post-treatment liquid containing a resin. According to Patent Document 1, it is stated that even in high-speed printing, a decrease in image quality due to transfer stains of the post-treatment liquid or ink can be prevented, and good rub resistance can be ensured.

[0004] Also, Patent Document 1 discloses a step of applying a pretreatment liquid onto a recording medium before the step of applying an aqueous ink to form an image. By providing the step of applying the pretreatment liquid, it is described that the pretreatment liquid causes an aggregation / thickening action with the aqueous ink, and high-quality images can be obtained even on coated paper of a low-absorption recording medium.

Summary of the Invention

Problems to be Solved by the Invention

[0005] When discharging the pretreatment liquid and ink with a single device, after the step of applying the pretreatment liquid, there is a problem that the pretreatment liquid remains as a mist and adheres to the periphery of the nozzle or inside the system. The ink solidifies due to the reaction between the adhered pretreatment liquid and the ink, resulting in contamination. In particular, when the periphery of the nozzle is contaminated, ejection failure occurs and a good image cannot be obtained. For this reason, it is necessary to clean the pretreatment liquid adhering to the periphery of the nozzle so as not to cause contamination. In addition to this, it is required to keep the periphery of the nozzle clean. However, in order to use a cleaning liquid or the like, it is necessary to add additional processing to the device, which causes a problem of increased manufacturing cost.

[0006] Accordingly, an object of the present invention is to provide a liquid ejection device that can keep the periphery of a nozzle clean and suppress an increase in manufacturing costs. **Means for Solving the Problems**

[0007] In order to solve the above problems, a liquid ejection device of the present invention includes a first ejection unit that ejects ink onto a recording medium, a second ejection unit that ejects a pretreatment liquid to a location where the ink is ejected, and a third ejection unit that ejects a diluent, and is characterized by including these. **Advantages of the Invention**

[0008] According to the present invention, it is possible to provide a liquid ejection device that can keep the periphery of a nozzle clean and suppress an increase in manufacturing costs. **Brief Description of the Drawings**

[0009]

Figure 1

Figure 2

Figure 3

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Figure 5

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Figure 7

[0010] Hereinafter, the liquid ejection device according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments shown below, and can be changed within the scope that those skilled in the art can conceive, such as other embodiments, additions, modifications, deletions, etc. As long as the functions and effects of the present invention are achieved in any aspect, it is included in the scope of the present invention.

[0011] The liquid ejection device of the present invention is characterized by including a first ejection unit that ejects ink onto a recording medium, a second ejection unit that ejects a pretreatment liquid to a location where the ink is ejected, and a third ejection unit that ejects a diluent.

[0012] Conventional garment printers can print white in addition to black, yellow, cyan, and magenta. For example, when printing on a cloth other than white, in order to obtain the target image, white ink is ejected, and then color ink is ejected thereon. In this case, it is necessary to retain the white ink on the surface of the recording medium. Also, when ejecting ink onto the cloth to form an image, the ink may penetrate into the depth of the fabric and the target image may not be obtained. For this reason, conventionally, a coater, a spray device, or the like, which is a means separate from the liquid ejection device, has been used to perform a treatment of previously applying a pretreatment liquid to the recording medium. Thus, when performing the pretreatment liquid with a separate device, it takes time and effort in the work, and it is difficult to improve productivity.

[0013] Therefore, the liquid ejection device of the present embodiment has a configuration including a first ejection unit that ejects ink onto a recording medium and a second ejection unit that ejects a pretreatment liquid to a location where the ink is ejected. Thereby, productivity can be improved. Examples of the ejection unit include a liquid ejection head. The liquid ejection head may be simply referred to as a head.

[0014] In this case, the mist of the pretreatment liquid adheres to the periphery of the head or inside the system, and the ink mist after discharging the ink adheres to and binds with the adhered pretreatment liquid, resulting in contamination. In contrast, it is conceivable to perform maintenance such as cleaning the periphery of the nozzle and inside the system with a cleaning liquid or the like. However, in addition to means for storing the cleaning liquid or the like, it is necessary to additionally provide means for supplying the cleaning liquid or the like, which increases the manufacturing cost of the apparatus.

[0015] Therefore, the liquid ejection apparatus of the present embodiment includes a third ejection unit having the same configuration as the first ejection unit and the second ejection unit, and a diluent is used in this third ejection unit. The diluent dilutes at least one of the pretreatment liquid and the ink. By using the diluent, it is possible to suppress an increase in the manufacturing cost of the apparatus without additional processing. The periphery of the nozzle and the like is cleaned using the diluent, and the diluent is also used for maintenance operations. Thereby, the periphery of the nozzle can be kept clean. Further, the diluent may be ejected onto the image.

[0016] The periphery of the nozzle may be the periphery of the nozzle for discharging the pretreatment liquid or the periphery of the nozzle for discharging the ink. Further, the periphery of the nozzle may be a part of the nozzle surface or the entire nozzle surface.

[0017] The recording medium may also be referred to as a printing medium, a medium, a media, etc. The recording medium can be appropriately selected, and examples thereof include plain paper, glossy paper, special paper, cloth (which may also be referred to as fabric), film, OHP sheet, general-purpose printing paper, and the like.

[0018] The pretreatment liquid contains a component that quickly fixes the ink. The pretreatment liquid contains, for example, a flocculant, an organic solvent, and water, and may also contain a surfactant, an antifoaming agent, a pH adjuster, an antiseptic and antifungal agent, a rust inhibitor, and the like. As the organic solvent, surfactant, antifoaming agent, pH adjuster, antiseptic and antifungal agent, and rust inhibitor, the same materials as those used for the ink can be used, and in addition, materials used for known treatment liquids can be used. The type of the flocculant is not particularly limited, and examples thereof include water-soluble cationic polymers, acids, polyvalent metal salts, and the like.

[0019] The pretreatment liquid used in this embodiment can be formulated as shown in Table 1 below, for example. By formulating it in this way, it becomes possible to stack and discharge ink while the pretreatment liquid remains wet without drying, improving productivity.

[0020]

Table 1

[0021] In Table 1, the glycol is not particularly limited and can be appropriately selected. Also, calcium nitrate tetrahydrate is an example of a flocculant. Regarding the numerical range of the content (%), the above and below are represented.

[0022] The ink can be appropriately selected. It may be one type or a plurality of types. In the case of a plurality of types, for example, black, cyan, magenta, and yellow inks can be used. In addition to these, white ink (white ink), clear ink, etc. can also be used.

[0023] As the ink, an ink mainly composed of water may be used, or an ink mainly composed of an organic solvent may be used. It is preferable that water or an organic solvent is 90% by mass or more, and more preferably 95% by mass or more in the ink as the main component.

[0024] When using an ink mainly composed of an organic solvent, by adopting a device configuration equipped with a diluent, the effect of keeping the periphery of the nozzle clean is improved. In the case of an ink mainly composed of an organic solvent, contamination may occur more easily than in the case of an ink mainly composed of water. By using a diluent capable of diluting the ink, it becomes easier to remove the fixed ink.

[0025] The organic solvent is not limited to the like, and examples thereof include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds, and the like.

[0026] A formulation example of the black ink is shown in Table 2 below. In Table 2, the glycol is not particularly limited and can be appropriately selected.

[0027]

Table 2

[0028] In Table 2, it is an example of black ink, but the above formulation can also be applied to other inks. When making other inks, the "*" in Table 2, that is, carbon black, may be changed to other colorants. Examples of the colorant include pigments.

[0029] The ink may be an ultraviolet curable ink. In this case, it is preferable that the liquid ejection device has irradiation means for irradiating ultraviolet rays. Since the liquid ejection device has irradiation means, there is no need to irradiate ultraviolet rays with another device, so productivity is improved. When the ultraviolet curable ink adheres around the head or the like, it may be difficult to remove. By using a diluent capable of diluting the ink, the adhered ink can be easily removed. Of course, if it can be washed with a diluent before adhesion, there is nothing better than this.

[0030] The ultraviolet curable ink contains, for example, a polymerizable compound (such as a monomer or an oligomer), a polymerization initiator, a colorant, an organic solvent (organic solvent), and the like.

[0031] The diluent only needs to be able to dilute the pretreatment liquid and can be appropriately selected. A liquid having a component used as a solvent of the pretreatment liquid is used as the diluent in this embodiment.

[0032] The diluent can be appropriately selected, and water is preferably used. When the diluent is water, it is easy to prepare and the device configuration becomes simpler. There are no particular restrictions on the water, and pure water may be used. For the diluent to be water, it is preferable that water is the main component in the diluent. For water to be the main component, for example, it is preferably 90% by mass or more, and more preferably 95% by mass or more in the diluent.

[0033] When water is used as the diluent in this embodiment, for example, it can be formulated as shown in Table 3 below. In Table 3, there are no particular restrictions on the preservative, and it can be appropriately selected. In the case of the formulation shown in Table 3, 95% by mass of water is contained, and it can be said that water is the main component.

[0034]

Table 3

[0035] In addition to water, the diluent is preferably a cleaning liquid. The cleaning liquid in this embodiment contains an organic solvent, a surfactant, and water. When the diluent is a cleaning liquid, it becomes easier to remove dirt. As the cleaning liquid used in this embodiment, for example, the cleaning liquid used for cleaning the inside of the ink supply path is effective.

[0036] The cleaning liquid used in this embodiment can be formulated, for example, as shown in Table 4 below. In Table 4, there are no particular restrictions on the glycol, and it can be appropriately selected. Also, there are no particular restrictions on the surfactant, and it can be appropriately selected.

[0037]

Table 4

[0038] Both the pretreatment liquid and the diluent are preferably transparent. By being transparent, it can be made unobtrusive even when discharged onto the recording medium.

[0039] In this embodiment, the diluent dilutes at least one of the pretreatment liquid and the ink. In this case, it becomes easier to keep the nozzle surfaces of the first ejection unit and the second ejection unit clean. When the diluent dilutes both the pretreatment liquid and the ink, the diluent for diluting the ink and the diluent for diluting the pretreatment liquid can be made common, and there is no need to increase the types of diluents. Also, since there is no need to increase the third ejection unit, an increase in manufacturing cost can be further suppressed.

[0040] To make the diluent dilute the pretreatment liquid or the ink, for example, at least one of the same solvents contained in the pretreatment liquid or the ink is included in the diluent. For example, by including at least one of the solvents contained in the pretreatment liquid or the ink in the diluent, the diluent can dilute the pretreatment liquid and / or the ink. To make the diluent dilute both the pretreatment liquid and the ink, for example, the solvents contained in the pretreatment liquid and the ink are included in the diluent. In the examples shown in Tables 1 to 3 above, water is contained in the pretreatment liquid, the ink, and the diluent. Also, in the examples shown in Tables 1, 2, and 4 above, it is preferable that water and glycerin are contained in the pretreatment liquid, the ink, and the diluent (cleaning liquid). In this case, it becomes easier to clean the nozzle surfaces of the first ejection unit and the second ejection unit and they can be kept cleaner.

[0041] When the diluent dilutes the ink, there are also the following advantages in addition to the above. For example, white ink has problems such that pigment components such as titanium oxide settle and tend to remain in the nozzle, and ejection failure is likely to occur. In contrast, in this example, since the diluent can also dilute the ink, it becomes easier to prevent ejection failure by wiping the nozzle with a wiping member holding the diluent.

[0042] The use of the diluent can be appropriately selected. The diluent may be brought into direct contact with the pretreatment liquid or the ink, or may be used by a method other than direct contact. For example, the diluent is applied to a member such as a wiping member and used to clean the pretreatment liquid or ink adhering to the periphery of the nozzle. In this case, a member other than the wiping member may also be used. When the diluent is used to clean the pretreatment liquid or ink, it can be diluted or softened by the diluent even before the pretreatment liquid or ink whose moisture has evaporated and whose viscosity has increased solidifies, and cleaning can be performed well.

[0043] Examples of the location to be cleaned by a wiping member or the like include the periphery of the nozzle for discharging the pretreatment liquid and the periphery of the nozzle for discharging the ink. In addition, for example, in addition to the nozzle surface such as the periphery of the nozzle, portions of the head other than the nozzle surface may be cleaned. Portions other than the head may be cleaned. Also, regarding bringing the diluent into direct contact with the pretreatment liquid or ink, mainly the pretreatment liquid or ink after being discharged is assumed.

[0044] As another use of the diluent, the diluent may be used for a cap member that caps the nozzle. By capping with the diluent held in the cap member, drying of the pretreatment liquid or ink can be reduced, and for example, even when printing is not performed for a long time, it is possible to prevent the pretreatment liquid or ink from clogging the nozzle and causing poor discharge.

[0045] The timing of using the diluent can be appropriately selected. For example, there is a case where the diluent is discharged after wiping when the user requests a refreshing operation. In addition, there is a case where the diluent is discharged when restarting the printing operation after not performing the printing operation for a long time. In the printing pattern printed during nozzle checking, it is not necessary to discharge the diluent.

[0046] As described above, the liquid ejection device of the present embodiment includes a third ejection unit that ejects a diluent. As the third ejection unit, a liquid ejection head can be used. By configuring the liquid ejection head to eject the diluent, the manufacturing cost of the device can be suppressed. The liquid ejection device of the present embodiment does not require dedicated means for supplying the diluent, and can have the same configuration as the first ejection unit and the second ejection unit, thereby suppressing additional costs.

[0047] By adopting the configuration of including a third ejection unit that ejects a diluent, for example, it is possible to eject the diluent onto a cap member, and it is also possible to perform an operation of retaining the diluent around the nozzle without ejecting the diluent as droplets. For example, by driving the third ejection unit with a low driving frequency, the diluent can be retained around the nozzle without being ejected as droplets. Note that the operation of retaining the diluent around the nozzle without ejecting it as droplets may also be referred to as an operation of oozing out the diluent.

[0048] On the other hand, when using a liquid ejection device that uses a diluent, a configuration can also be considered in which additional processing is performed on the supply path to supply the diluent to the nozzles that eject the pretreatment liquid or ink for direct maintenance. However, in this case, additional processing is required for the device, resulting in an increase in manufacturing cost.

[0049] The liquid ejection device of the present embodiment includes a first ejection unit and a second ejection unit, and is capable of ejecting a pretreatment liquid and ink. Therefore, it is possible to omit the need to perform pretreatment on a recording medium in advance with another device, improving productivity. The liquid ejection device of the present embodiment can perform the ejection of the pretreatment liquid and ink with a single device, and by using a third ejection unit that ejects a diluent, the diluent can be used while suppressing an increase in cost. The liquid ejection device of the present embodiment can perform the operations from pretreatment to printing with a single device, and can perform good maintenance while suppressing the manufacturing cost.

[0050] An example of the liquid ejection device according to this embodiment will be described. Here, mainly an example of the DTG (Digital to Garment or Direct To Garment) method will be described, but the liquid ejection device of the present invention is also applicable to the DTF (Digital to Film or Direct To Film) method.

[0051] FIG. 1 shows a perspective view of the liquid ejection device 1 with each cover member closed, and FIG. 2 shows a plan view. FIG. 3 shows a perspective view of the liquid ejection device 1 with the cover member open, and FIG. 4 shows a plan view. The direction X in FIG. 1 is the front-rear direction or the sub-scanning direction or the recording medium conveyance direction of the liquid ejection device, the direction Y is the width direction or the main scanning direction of the liquid ejection device, and the direction Z is the vertical direction. The direction X and the direction Y are directions parallel to the liquid ejection surface of the recording medium arranged on the stage, but there may be some errors. The directions X, Y, and Z are orthogonal to each other.

[0052] As shown in FIGS. 1 and 2, the liquid ejection device 1 has a stage 3 in front of the housing 2. The stage 3 is provided on the guide rail 4. The guide rail 4 extends in the direction X. An operation panel 5 is provided on the front side of the housing 2. An ink cartridge 6 is detachably attached to the side surface of the housing 2. A front cover 7 and a rear cover 8 as cover members are provided above the housing 2.

[0053] The upper surface of the stage 3 is a placement surface for placing the recording medium, and is flat. The upper surface of the stage 3 is a surface parallel to the directions X and Y. The stage 3 moves on the guide rail 4 and is provided so as to be reciprocally movable in both directions of the direction X. Also, the stage 3 is provided so as to be movable up and down in the Z direction. Thereby, the height of the recording medium arranged on the stage 3 can be adjusted.

[0054] The state of FIG. 1 where the front cover 7 moves backward and the rear cover 8 moves forward is the state where each cover is closed. On the other hand, the state of FIG. 3 where the front cover 7 moves forward and the rear cover 8 moves backward is the state where each cover is open.

[0055] By configuring the front cover 7 and the rear cover 8 to be opened and closed by sliding in this way, for example, compared with a configuration that opens and closes vertically, the occupied area of the liquid ejection device including the opening and closing area of the cover member can be reduced. The front cover 7 and the rear cover 8 have openings at both ends in the front-rear direction. In a state where the front cover 7 and the rear cover 8 are closed, the front cover 7 and the rear cover 8 are arranged continuously in the front-rear direction.

[0056] As shown in FIGS. 3 and 4, the device main body portion 50 of the liquid ejection device 1 includes a housing 2, liquid ejection portions 9A, 9B provided on the housing 2, and the like. In particular, in this embodiment, the device main body portion 50 is a portion other than the front cover 7 and the rear cover 8 of the liquid ejection device 1. The front cover 7 and the rear cover 8 are provided slidably in the X direction with respect to the device main body portion 50.

[0057] When the front cover 7 and the rear cover 8 are opened, the liquid ejection portions inside the liquid ejection device 1 are opened to the outside. By opening the liquid ejection portion to the outside, it becomes possible to clean the maintenance unit 30, the liquid ejection head and its periphery, or to replace the carriage. Further, during image formation, the front cover 7 and the rear cover 8 are in a closed state. As a result, the liquid ejection portions 9A, 9B are covered by the front cover 7 or the rear cover 8, and the operating portions such as the carriage of the liquid ejection portions 9A, 9B cannot be accessed from the outside.

[0058] Further, by arranging the liquid ejection portions 9A, 9B in the closed space inside the front cover 7 or the rear cover 8, it is possible to prevent ink mist from scattering to the periphery during the liquid ejection operation, and the fan provided in the liquid ejection portions 9A, 9B circulates the air flow inside the front cover 7 or the rear cover 8, and the generated ink mist can be circulated and recovered inside the front cover 7 or the rear cover 8.

[0059] The liquid ejection device 1 of this embodiment has two liquid ejection portions 9A, 9B in the direction X. The liquid ejection portion 9A ejects color and white inks. The liquid ejection portion 9B ejects a pretreatment liquid.

[0060] Note that the liquid discharged from each of the liquid discharge units 9A and 9B is not limited to the above, and may be in a form of discharging any liquid among color ink, white ink, and pretreatment liquid. In particular, when the recording medium is a fabric, it is preferable to apply a pretreatment liquid before forming an image with ink. Therefore, it is preferable that one of the liquid discharge units discharges the pretreatment liquid. The pretreatment liquid is preferably discharged from the liquid discharge unit 9B on the upstream side of the conveyance of the recording medium.

[0061] Since the liquid discharge units 9A and 9B have the same configuration, the liquid discharge unit 9A will be described below. The liquid discharge unit 9A includes a carriage 10A, a guide rod 11, an electrical component unit 12 composed of a substrate, an electrical equipment cover, etc., and a maintenance unit 30. The liquid discharge units 9A and 9B or the carriages 10A and 10B are also simply referred to as the liquid discharge unit 9 or the carriage 10.

[0062] The guide rod 11 extends in the main scanning direction. The carriage 10 is provided so as to be movable in the main scanning direction along the guide rod 11. The carriage 10 has a plurality of liquid discharge heads. The maintenance unit 30 is provided at a position facing the guide rod 11 outside the liquid discharge area on one side in the left-right direction.

[0063] The maintenance unit 30 includes a wiping member for cleaning the nozzle surface of the liquid discharge head, a suction mechanism for sucking the nozzle surface, etc. The wiping member may be a wiper made of rubber or the like, or a web made of non-woven fabric or the like.

[0064] An example of the process of forming an image on the recording medium will be described. First, place the recording medium on the stage 3 and convey it on the guide rail 4. Then, convey it to the rear side of the liquid ejection device, and apply the pretreatment liquid to the recording medium by the liquid ejection unit 9B. Specifically, while moving the carriage 10B in the main scanning direction along the guide rod 11, apply the pretreatment liquid from the nozzles provided in the liquid ejection head to the recording medium over the main scanning direction. By repeating this at each position in the sub-scanning direction, the pretreatment liquid is applied to the recording medium.

[0065] Thereafter, move the stage 3 forward, and eject each color of the color onto the recording medium by the liquid ejection unit 9A in the same manner. When performing white printing on the recording medium, for example, first eject white ink by the liquid ejection unit 9A, then move the stage 3 to the rear side of the liquid ejection unit 9A again, and eject color ink onto the recording medium by the liquid ejection unit 9A. Thereby, an image can be formed on the recording medium.

[0066] A configuration example of the supply unit will be described. In FIGS. 1 and 3, an ink cartridge 6 is detachably attached to the side surface of the housing 2 as the supply unit. Ten ink cartridges 6 are provided here. Although not particularly limited, for example, as the ink cartridges 6 on the front side of the apparatus, use ink cartridges containing yellow, magenta, white, cyan, and black inks. As the ink cartridges 6 on the back side of the apparatus, use ink cartridges containing the pretreatment liquid and the diluent. Thus, in this embodiment, the pretreatment liquid, ink, and diluent can be made into supply units having the same configuration.

[0067] Regarding the description of the liquid ejection device described above, the following supplements are made. When using a fabric as the recording medium, it may be possible to eliminate the fluff and wrinkles on the printing surface. As a method, for example, a method of pressing the fabric with a heating surface using an iron or a heat press machine can be mentioned. Thus, the recording medium used in this embodiment may be processed before being attached to the liquid ejection device of this embodiment.

[0068] The recording medium is attached to the platen of the liquid ejection device so as not to become wrinkled (concave and convex). The platen may also be referred to as a holding member or the like. After receiving a printing instruction from a device such as a PC or a smartphone, the liquid ejection device may perform an operation check.

[0069] The platen with the recording medium placed thereon moves to the printing start position on the back side of the device. At this time, the built-in position sensor detects the height so that the upper part of the recording medium does not contact the nozzle surface of the head. The distance between the surface of the recording medium and the nozzle surface (also referred to as Gap, etc.) is preferably as narrow as possible, and is set so that the surface of the recording medium and the nozzle surface do not contact each other. The Gap is preferably, for example, 0.5 mm to 7 mm.

[0070] The position sensor detects, for example, whether the laser light is blocked by the recording medium or the platen. When the laser light is blocked, it is regarded as an error, the plan stops, and returns to the initial position on the front side of the device. It is preferable that the device is set to automatically judge and adjust the distance between the surface of the recording medium and the nozzle surface.

[0071] After the platen passes the position sensor without error, it moves to the printing start position. Next, when the device receives a printing start signal, the platen moves to the leading writing position.

[0072] The carriage operates while reading an encoder provided in parallel with the guide rod along the guide rod provided in the main scanning direction, and ejects liquid onto the recording medium set on the platen. The moving direction of the carriage is also referred to as the main scanning direction. The platen moves in the sub-scanning direction on the guide rail in accordance with the operation of the carriage. Printing is performed while the platen moves from the back side to the front side.

[0073] The liquid ejecting device of the present embodiment is provided with two carriages on the back side and the front side. For example, on the carriage on the back side, a head for ejecting a pretreatment liquid and a head for ejecting a diluting liquid are provided side by side. On the carriage on the front side, heads for ejecting yellow, magenta, cyan, and black color inks and a head for ejecting white ink are provided side by side.

[0074] The method of printing on the fabric is different between white ink and color ink. When printing on a white fabric, it is sufficient to eject color ink. When printing on a fabric other than white, for example, a black fabric, if only color ink is ejected, the color tone will change due to the influence of the background. To prevent this, when printing on a fabric other than white, a white solid is printed over the entire printing area, and then the recording medium is moved to the printing start position, and color ink is ejected. That is, printing is performed by overlapping white ink and color ink.

[0075] This example will be described again. The ink includes color ink and white ink, the recording medium is cloth, and the first ejection unit ejects white ink onto the recording medium when the recording medium is other than white, and ejects the color ink onto the location where the white ink has been ejected. By doing so, a desired good image can be formed even on a fabric other than white.

[0076] After ejecting the ink, the recording medium is taken out from the platen. If necessary, post-processing such as heating and fixing is performed using a heat press machine or the like.

[0077] In the liquid ejecting device of the present embodiment, one head is mounted for each of the inks of white, cyan, magenta, yellow, and black. Although not particularly limited, each color head is provided with about 200 nozzles, and the heads are provided in parallel. However, the present invention is not limited to such a configuration, and one color ink may be ejected by a plurality of heads. Similarly, for the pretreatment liquid and the diluting liquid, a plurality of heads may be mounted respectively.

[0078] As described above, the recording medium can be appropriately selected. For example, as the fabric, cotton, chemical fiber, etc. can be used. Also, even if it is the same cotton, it may be a thin fabric or a canvas fabric, and it can be appropriately selected.

[0079] When using, for example, a thin polyester as the recording medium, a pretreatment liquid is used. By previously discharging and applying the pretreatment liquid to the location where the ink is to be discharged, the target image can be obtained. When discharging the ink without discharging the pretreatment liquid, it will deeply penetrate into the fabric weave, making it difficult to obtain the target image.

[0080] The arrangement of the first discharge unit, the second discharge unit, and the third discharge unit is not particularly limited and can be appropriately selected. In the case of the liquid discharge device of this embodiment, since the printing start position is on the back side of the device, for example, it is preferable to arrange the second discharge unit for discharging the pretreatment liquid on the back carriage. Thereby, the efficiency can be improved.

[0081] FIG. 5 is a schematic plan view for explaining an example of the head arrangement of the carriages 10A and 10B in the liquid discharge device such as FIG. 3. FIG. 5 shows the view when looking at the nozzle surface from the recording medium side. However, in the liquid discharge device of the present invention, the number of carriages is not limited to two and can be appropriately changed. Also, the arrangement and number of the heads are not limited to the illustrated example and can be appropriately changed.

[0082] In the example shown in FIG. 5(A), the carriage 10A is equipped with eight heads 22Y, 22M, 22C, 22K, 22D1 to 22D4, and the carriage 10B is equipped with eight heads 22W1, 22W2, 22P1, 22P2, 22D5 to 22D8. When explaining the heads without distinction, they are referred to as heads 22, etc.

[0083] The example shown in Fig. 5(A) uses the Ri2000 garment printer manufactured by Ricoh. On the front carriage 10A, heads 22Y, 22M, 22C, and 22K for discharging yellow, magenta, cyan, and black inks are arranged side by side. Also, adjacent to each of these heads, heads 22D1 to 22D4 for discharging diluent are provided. On the rear carriage 10B, heads 22W1, 22W2 for discharging white ink and heads 22P1, 22P2 for discharging pretreatment liquid are provided. Also, adjacent to each of these heads, heads 22D5 to 22D8 for discharging diluent are provided.

[0084] In the illustrated example, during maintenance, for example, diluent is applied from the nozzles of the diluent to a wiping sheet (an example of a wiping member), and the heads for discharging ink and the heads for discharging pretreatment liquid are wiped with the wiping sheet. Thereby, the nozzle surfaces of the heads for discharging ink and the heads for discharging pretreatment liquid can be cleaned.

[0085] As in the illustrated example, it is preferable to make the nozzle surface of the head for discharging ink adjacent to the nozzle surface of the head for discharging diluent. In this case, when applying diluent to the wiping member for wiping, it becomes easier to wipe the nozzle surface of the head for discharging ink. Similarly, it is preferable to make the nozzle surface of the head for discharging pretreatment liquid adjacent to the nozzle surface of the head for discharging diluent. In this case, when applying diluent to the wiping member for wiping, it becomes easier to wipe the nozzle surface of the head for discharging pretreatment liquid.

[0086] As in the illustrated example, it is preferable to arrange on one carriage 10A the nozzle surfaces of the head for discharging ink and the head for discharging diluent so as to be flat, and set this as one set for installation. By doing so, it is possible to prevent the piping in the vicinity of the nozzles from becoming complicated. Similarly, it is preferable to arrange on one carriage 10B the nozzle surfaces of the head for discharging pretreatment liquid and the head for discharging diluent so as to be flat, and set this as one set for installation. By doing so, it is possible to prevent the piping in the vicinity of the nozzles from becoming complicated.

[0087] In this example, the heads 22Y, 22M, 22C, and 22K are the first ejection units, the heads 22P1 and 22P2 are the second ejection units, and the heads 22D1 to 22D8 are the third ejection units. Note that the types, numbers, etc. of the color inks to be ejected are not limited to the illustrated examples. The types of color inks are not limited to KCMY. The number of color inks may be one. Also, the number of nozzle rows for ejecting white ink is not limited to the illustrated example. Further, the number of heads for ejecting a pretreatment liquid or a diluent and the number of nozzle rows are not limited to the illustrated example.

[0088] FIG. 5(B) is a schematic plan view for explaining an example of the nozzle arrangement of the head 22K and the nozzle arrangement of the head 22D4 in FIG. 5(A). The figure is a view when seen from the nozzle surface side. When the head is mounted on the liquid ejection device, the nozzle surface is provided to face downward, for example, and the liquid is ejected from the upper side to the lower side.

[0089] For the sake of explanation, the nozzles for ejecting black ink are denoted by reference numeral 65, and the nozzles for ejecting the diluent are denoted by reference numeral 61. The shape, size, etc. of the nozzles can be changed as appropriate.

[0090] In the illustrated example, the nozzles are arranged in two rows. When the number of nozzle rows is two, it is possible to cope with high speed. Also, in the illustrated example, the nozzle rows are arranged with a shift, for example, in a staggered arrangement. In this case, a solid image can be formed by ejecting the liquid from the nozzles of two rows simultaneously. As described above, during maintenance, the diluent is discharged from the nozzles of the head for ejecting the diluent, and the diluent is applied to the wiping member to wipe the nozzle surfaces of other heads, so that the nozzle surfaces can be cleaned.

[0091] When discharging the pretreatment liquid and the ink with a single device, after discharging the pretreatment liquid, the pretreatment liquid may remain as a mist. In this case, the discharged ink may react with the mist of the pretreatment liquid and solidify, and may adhere to the nozzle surface or inside the system. As a countermeasure, a head for discharging a diluent is mounted on the liquid discharge device of the present embodiment.

[0092] As a method for removing the mist of the pretreatment liquid or ink adhering to the head surface, generally, there is an operation of wiping with a rubber-like wiper provided in the maintenance means of the device. In the case of such a method, the nozzle surface to which the pretreatment liquid or ink adheres can be wiped, but it is difficult to peel off the solidified ink that has reacted with the pretreatment liquid from the nozzle surface. In addition, it is also possible that lint generated from the fabric adheres to the nozzle surface, causing a malfunction in the wiping operation by the wiper.

[0093] In the present embodiment, by performing wiping using a diluent, the above-mentioned problems can be prevented. An example in this case is described below. In this example, the first discharge unit, the second discharge unit, and the third discharge unit each have a nozzle surface on which nozzles for discharging each liquid are formed. The liquid discharge device of this example includes a wiping member for wiping the nozzle surface of the first discharge unit, the second discharge unit, or the third discharge unit, and a diluent is applied to the wiping member to perform a wiping operation. By doing so, the nozzle surface can be cleaned well. In addition, it becomes easier to remove lint and the like adhering to the nozzle surface. This wiping operation is preferably performed on the liquid pretreatment liquid or ink that adheres to and reacts with the nozzle surface before solidifying.

[0094] The method of applying the diluent to the wiping member is not particularly limited and can be appropriately selected. The third discharge unit in this example performs an operation of oozing out the diluent from the nozzle and can retain the diluent around the nozzle. The wiping member wipes the nozzle surface of the third discharge unit, holds the retained diluent, and wipes the nozzle surface of the first discharge unit and / or the nozzle surface of the second discharge unit.

[0095] In this case, it is possible to prevent a large change in the configuration of the apparatus and suppress an increase in manufacturing cost. Since the wiping member can wipe the nozzle surface of the third discharge portion, the diluent can be applied to the wiping member, so that the wiping member can easily hold the diluent. To allow the diluent to ooze out from the nozzle and retain the diluent around the nozzle, for example, the drive frequency can be lowered to drive the third discharge portion, and the diluent can be applied to the wiping member without a complicated apparatus configuration.

[0096] To adjust the amount of the diluent held by the wiping member, for example, the operations of oozing out the diluent and the number of times of wiping the nozzle surface of the third discharge portion are appropriately adjusted. When the amount of the diluent held by the wiping member is small, the operations of oozing out the diluent and wiping the nozzle surface of the third discharge portion are performed a plurality of times.

[0097] When the wiping member wipes the nozzle surface of the third discharge portion, the range of the nozzle surface to be wiped may be only around the nozzle or the entire surface.

[0098] Examples of the wiping member include a wiper, a web, etc., and a wiper is preferable. When it is a wiper, the diluent can be easily applied by oozing out the diluent and wiping the nozzle surface of the third discharge portion with the wiper. The diluent may be discharged onto the web for cleaning.

[0099] The wiper may also be referred to as a wiper member or the like, or a wiper-shaped wiping member or the like. As the wiper, a blade-shaped wiper blade can be used, and the material can be, for example, a rubber-like material.

[0100] An example of the operation of oozing out the diluent will be described. The third discharge unit in this example has a driving means for performing an operation of discharging a diluent, and the driving means preferably performs an operation of causing the diluent to ooze out from the nozzle at a driving frequency of 7 kHz or less. By driving at a driving frequency of 7 kHz or less, an appropriate amount of the diluent can be retained around the nozzle without the diluent flying out from the nozzle as droplets.

[0101] To prevent the diluent from flying out from the nozzle as droplets, it is necessary to suppress the driving frequency to 10 kHz or less, and to retain an appropriate amount of the diluent around the nozzle, it is preferable to set the driving frequency to 7 kHz or less. Also, to discharge the diluent from the nozzle, it is preferable to set the driving frequency to 1 kHz or more.

[0102] Retaining the diluent around the nozzle may also be referred to as causing the diluent to stay around the nozzle or retaining the diluent on the nozzle surface. The wiping operation by the wiping member is performed, for example, after printing or during maintenance.

[0103] FIG. 6 is a schematic cross-sectional view for explaining this example. In the figure, the nozzle 61 and the nozzle surface 62 of the third discharge unit are shown, and a wiper 63 is shown as the wiping member. The arrow in the figure schematically indicates the moving direction of the wiper 63.

[0104] This example is a case where the diluent 60 is caused to ooze out with the driving frequency set to 1 to 7 kHz. As shown in the figure, the diluent 60 does not fly out as droplets and stays on the nozzle surface in a hemispherical shape. By the wiper 63 wiping the nozzle surface 62, the diluent 60 staying on the nozzle surface can be attached to the wiper 63.

[0105] By wiping the nozzle surface to which the pretreatment liquid has adhered with a wiping member holding a diluent, the nozzle surface can be kept clean. Also, by wiping the nozzle surface with a wiping member holding a diluent, the solidified ink can be removed, and the nozzle surface can be kept clean. Further, by attaching the diluent to the wiper and wiping, it becomes difficult for solids to adhere to the wiper, and it becomes easier to keep the wiper surface clean.

[0106] In the case of the example shown in FIG. 5, for example, the wiping member can be impregnated with the diluent by wiping the nozzle surfaces of the heads 21f and 21g, and by wiping the heads 21h to 21j in the same direction as the wiping, the periphery of the head that discharges the pretreatment liquid and the nozzle surface can be wiped. Also, for example, after the wiping member is impregnated with the diluent by wiping the nozzle surfaces of the heads 21f and 21g, the wiping member is moved to wipe the heads 21a to 21e. Thereby, the periphery of the nozzle that discharges the ink and the nozzle surface can be wiped.

[0107] As described above, in the present embodiment, the diluent is not limited to being used for wiping, and it may be used for other purposes. For example, the diluent may be used for the cap member. An example in this case will be described.

[0108] The liquid ejection device of this example has a cap member that caps the first ejection portion and / or the second ejection portion. The third ejection portion ejects a diluent onto the cap member, and the cap member caps while holding the diluent. By capping while holding the diluent in the cap member, drying of the pretreatment liquid and ink can be reduced. For example, even when printing is not performed for a long time, it is possible to suppress the pretreatment liquid and ink from clogging the nozzles and causing ejection failure. By capping while holding the diluent in the cap member, the nozzle surfaces of the first ejection portion and the second ejection portion can be kept cleaner. Also, by capping while holding the diluent in the cap member, the nozzle surfaces of the ejection portions can be washed.

[0109] FIG. 7 is a schematic cross-sectional view for explaining this example. In this example, the diluent 60 is discharged onto the cap member 64 by the third discharge portion, and the diluent 60 is held inside the cap member 64. The cap member 64 caps the nozzle surfaces of the first discharge portion and the second discharge portion while holding the diluent 60.

[0110] In the figure, the nozzle 65 is shown, which is distinguished from the nozzle 61 of the third discharge portion in FIG. 6. The cap member 64 caps the first discharge portion and / or the second discharge portion, and the reference numeral of the nozzle is changed to indicate this. The cap member 64 may cap one head or may cap a plurality of heads together. The cap member may be referred to as a head protection cap or simply as a cap.

[0111] In FIG. 7, for the sake of explanation, a broken line is drawn between the nozzle 65 and the diluent 60 on the cap member 64 side. It is preferable that the nozzle 65 and the diluent 60 on the cap member 64 side are in contact with each other. When they are in contact, the nozzle surface of the discharge portion can be sufficiently cleaned.

[0112] Next, another embodiment of the present invention will be described. The liquid ejection device of the present invention is also applicable to a DTF printer. An example will be described below.

[0113] In the case of the DTF (Digital to Film or Direct To Film) method, the recording medium is a transfer base material for transferring an image to a material to be transferred. A pretreatment liquid and ink are ejected onto the transfer base material to form a transfer image. Here, the pretreatment liquid will be supplemented. If there is no problem with the compatibility between the transfer base material and the ink, the pretreatment liquid is not necessary. In practice, the transfer base material is coated with a dedicated coating agent and there is no problem with the compatibility with aqueous ink. However, some transfer base materials have the property of repelling ink, and the pretreatment liquid also has a role like a binder (also referred to as an adhesive liquid, adhesive, etc.), and transfers the transfer image on the transfer base material to a material to be transferred such as clothing. By doing so, an image can be formed on the material to be transferred.

[0114] The substrate for transfer is preferably a non-permeable substrate, and examples of the non-permeable substrate include films and the like. The material to be transferred is preferably cloth. Examples of cloth include clothing such as T-shirts, and in addition, bags and the like can also be mentioned.

[0115] When transferring the transfer image formed on the transfer substrate to the material to be transferred, heating or pressurization may be performed. By performing heating and / or pressurization during transfer, it becomes easier to transfer.

[0116] In the case of the DTF method, the third ejection unit may eject a diluent onto the image transferred to the material to be transferred. Further, when the third ejection unit ejects the diluent onto the image transferred to the material to be transferred, the diluent is ejected onto a part of the image transferred to the material to be transferred. In this case, by applying the diluent to the discolored part of the image transferred to the material to be transferred, the discoloration can be eliminated. Or the discoloration can be reduced.

[0117] An example thereof will be described. With the liquid ejection device of the present embodiment, a pretreatment liquid and ink were ejected onto a recording medium that is a transfer substrate to form a transfer image. In this example, black ink was used to form a black-based image. Next, the image formed on the recording medium was transferred to a T-shirt that is the material to be transferred. The black-based image portion at the end of the printing range turned white. The reason for the white discoloration is considered to be, for example, that the main agent due to the drying of the pretreatment liquid, etc. has emerged as white. Originally, there would be no problem if the pretreatment liquid was the same size as the printed image. However, depending on the type of T-shirt (material, twist, etc.), the pretreatment liquid may spread unexpectedly. When the diluent was sprayed (ejected) onto this discolored area, the discoloration disappeared. Although the details are unclear, applying the diluent to the discolored area was effective in eliminating the discoloration of the transferred image. Even when the diluent was sprayed (ejected), the image transferred to the material to be transferred did not bleed. From this, in the case of the DTF method, it is considered effective to eject the diluent onto the image transferred to the material to be transferred.

[0118] As a method of discharging a diluent to a part of an image transferred onto a transfer material, for example, a discolored part, there is, for example, a method of determining a discolored part with a reflection type image densitometer or the like and discharging the diluent from a nozzle 61 corresponding to that part.

[0119] Aspects of the present invention are, for example, as follows. <1> A first discharge unit that discharges ink onto a recording medium, A second discharge unit that discharges a pretreatment liquid to a location where the ink is discharged, And a third discharge unit that discharges a diluent, A liquid discharge device characterized by the above. <2> The diluent dilutes at least one of the pretreatment liquid and the ink. The liquid discharge device according to <1>, characterized by the above. <3> The first discharge unit, the second discharge unit, and the third discharge unit each have a nozzle surface on which nozzles for discharging each liquid are formed, A wiping member for wiping the nozzle surface of the first discharge unit, the second discharge unit, or the third discharge unit is provided, and the diluent is applied to the wiping member to wipe the nozzle surface. The liquid discharge device according to <1> or <2>, characterized by the above. <4> The third discharge unit performs an operation of oozing out the diluent from the nozzle and can retain the diluent around the nozzle. The wiping member wipes the nozzle surface of the third discharge unit, holds the retained diluent, and wipes the nozzle surface of the first discharge unit and / or the nozzle surface of the second discharge unit. The liquid discharge device according to <3>, characterized by the above. <5> The third discharge unit has a driving means for performing an operation of discharging the diluent, The driving means performs an operation of oozing out the diluent from the nozzle at a driving frequency of 7 kHz or less. The liquid ejection device according to <4>, characterized in that... <6> The ink is mainly composed of an organic solvent. The liquid ejection device according to any one of <1> to <5>, characterized in that... <7> It has irradiation means for irradiating ultraviolet rays, The ink is an ultraviolet curable ink. The liquid ejection device according to any one of <1> to <5>, characterized in that... <8> It has a cap member for capping the first ejection part and / or the second ejection part, The third ejection part ejects the diluent onto the cap member, The cap member caps while holding the diluent. The liquid ejection device according to any one of <1> to <7>, characterized in that... <9> The diluent is water. The liquid ejection device according to any one of <1> to <8>, characterized in that... <10> The diluent is a cleaning liquid, and the cleaning liquid contains an organic solvent, a surfactant, and water. The liquid ejection device according to any one of <1> to <8>, characterized in that... <11> The ink contains color ink and white ink, The recording medium is cloth, When the recording medium is other than white, the first ejection part ejects the white ink onto the recording medium, and ejects the color ink onto the portion where the white ink has been ejected. The liquid ejection device according to any one of <1> to <10>, characterized in that... <12> The recording medium is a transfer base material for transferring an image to a material to be transferred. The liquid ejection device according to any one of <1> to <10>, characterized in that... <13> The substrate for transfer is a non-permeable substrate, and the material to be transferred is a cloth. The liquid ejection device according to <12>, characterized in that. <14> The third ejection unit ejects the diluent onto the image transferred onto the material to be transferred. The liquid ejection device according to <12> or <13>, characterized in that. <15> When the third ejection unit ejects the diluent onto the image transferred onto the material to be transferred, the diluent is ejected onto a part of the image transferred onto the material to be transferred. The liquid ejection device according to <14>, characterized in that.

Explanation of Signs

[0120] 1 Liquid ejection device 3 Stage 7 Front cover (cover member) 8 Rear cover (cover member) 9A, 9B Liquid ejection parts 10 Carriage 21 Head 22 Nozzle row 60 Diluent 61, 65 Nozzles 62 Nozzle surface 63 Wiper 64 Cap member

Prior Art Documents

Patent Documents

[0121]

Patent Document 1

Claims

1. A first ejection unit that ejects ink onto a recording medium, a second ejection unit that ejects a pretreatment liquid onto a location where the ink is ejected, and a third ejection unit that ejects a diluent, characterized in that it is a liquid ejection device comprising the above.

2. The diluent dilutes at least one of the pretreatment liquid and the ink, characterized in that it is the liquid ejection device according to Claim 1.

3. The first ejection unit, the second ejection unit, and the third ejection unit each have a nozzle surface formed with nozzles for ejecting each liquid, and it is provided with a wiping member for wiping the nozzle surface of the first ejection unit, the second ejection unit, or the third ejection unit, and the diluent is applied to the wiping member to wipe the nozzle surface, characterized in that it is the liquid ejection device according to Claim 1.

4. The third ejection unit performs an operation of oozing out the diluent from the nozzle and can retain the diluent around the nozzle, and the wiping member wipes the nozzle surface of the third ejection unit, holds the retained diluent, and wipes the nozzle surface of the first ejection unit and / or the nozzle surface of the second ejection unit, characterized in that it is the liquid ejection device according to Claim 3.

5. The third ejection unit has a driving means for performing an operation of ejecting the diluent, and the driving means performs an operation of oozing out the diluent from the nozzle at a driving frequency of 7 kHz or less, characterized in that it is the liquid ejection device according to Claim 4.

6. The ink has an organic solvent as a main component, characterized in that it is the liquid ejection device according to Claim 1.

7. It has an irradiation means for irradiating ultraviolet rays, and the ink is an ultraviolet curable ink, characterized in that it is the liquid ejection device according to Claim 1.

8. It has a cap member for capping the first ejection unit and / or the second ejection unit, the third ejection unit ejects the diluent onto the cap member, and the cap member caps while holding the diluent, characterized in that it is the liquid ejection device according to Claim 1.

9. The diluent is water, characterized in that it is the liquid ejection device according to Claim 1.

10. The diluent is a cleaning liquid, and the cleaning liquid contains an organic solvent, a surfactant, and water, characterized in that it is the liquid ejection device according to Claim 1.

11. The ink includes color ink and white ink, and the recording medium is cloth, When the recording medium is other than white, the first ejection unit ejects the white ink onto the recording medium, and ejects the color ink onto the location where the white ink has been ejected. The liquid ejection device according to claim 1, characterized in that.

12. The recording medium is a transfer base material for transferring an image to a material to be transferred. The liquid ejection device according to claim 1, characterized in that.

13. The transfer base material is a non-permeable base material, and the material to be transferred is cloth. The liquid ejection device according to claim 12, characterized in that.

14. The third ejection unit ejects the diluent onto the image transferred to the material to be transferred. The liquid ejection device according to claim 12, characterized in that.

15. When the third ejection unit ejects the diluent onto the image transferred to the material to be transferred, the third ejection unit ejects the diluent onto a part of the image transferred to the material to be transferred. The liquid ejection device according to claim 14, characterized in that.

Images