Drying device for inkjet printers and inkjet printers equipped with the same

Abstract

To provide a dryer which can maintain ink dry efficiency and inhibit increase of humidity of a room in which an inkjet printer is installed.SOLUTION: A dryer 20 of an inkjet printer includes: a casing 23 in which a suction port 21 and a discharge port 22 are formed; a heater 24 which is disposed within the casing 23; a fan 25 which suctions air from the suction port 21 into the casing 23 and blows air so that air in the casing 23 is discharged from the discharge port 22; and a dehumidification member 30 which has a dehumidification passage 34 which causes air discharged from the discharge port 22 and blown onto a recording medium 5 to flow while dehumidifying the air.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a drying device for an inkjet printer and an inkjet printer including the same.

Background Art

[0002] Conventionally, an inkjet printer that performs printing on a recording medium by an inkjet method is known. This type of inkjet printer includes, for example, a platen on which a recording medium is placed, an ink head that discharges ink onto the recording medium placed on the platen, and an apron that is disposed in front of the platen and supports the recording medium onto which the ink has been discharged. Further, depending on the type of ink used, a drying device is provided in the inkjet printer to promote drying of the ink discharged onto the recording medium.

[0003] For example, Patent Document 1 describes a drying device disposed to face an apron. The drying device heats the air sucked in from a suction port with a heater and discharges it from a discharge port. The drying device blows the heated high-temperature air onto the recording medium on the apron. Thereby, drying of the ink on the recording medium is promoted. By providing a drying device in the inkjet printer, drying of the ink discharged onto the recording medium can be efficiently performed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The drying unit draws in air from its surroundings through an intake port and discharges it through an exhaust port. The discharged air is blown onto the recording medium and released back into the environment around the drying unit, but some of the air is drawn back in through the intake port and discharged through the exhaust port to be blown onto the recording medium again.

[0006] Inkjet printers sometimes use water-based inks. Because water-based inks contain a relatively large amount of water, a lot of that water evaporates when they dry. As a result, the air that has been sprayed onto the recording medium and dried contains a lot of moisture, making it high-humidity air.

[0007] For efficient ink drying, it is preferable that the air blown onto the recording medium has low humidity. This is because if high-humidity air is drawn back into the drying device and blown onto the recording medium, the ink drying efficiency will decrease. Furthermore, if high-humidity air is discharged from the drying device for an extended period, the humidity in the room where the inkjet printer is installed will increase.

[0008] The present invention has been made in view of the above, and its object is to provide a drying device that can maintain the drying efficiency of the ink and suppress the rise in humidity in the room in which the inkjet printer is installed, and an inkjet printer equipped therewith. [Means for solving the problem]

[0009] The inkjet printer drying apparatus according to the present invention comprises a casing having an intake port and an exhaust port opening toward a recording medium on which ink has been ejected; a heating element disposed inside the casing; a fan that blows air so that air is drawn into the casing from the intake port and the air inside the casing is discharged from the exhaust port; and a dehumidifying member having a dehumidifying passage that allows the air discharged from the exhaust port and blown onto the recording medium to pass through while being dehumidified.

[0010] According to the drying device for the inkjet printer described above, air drawn into the casing from the intake port is heated by a heating element and discharged from the exhaust port as high-temperature air. The high-temperature air discharged from the exhaust port is blown onto the recording medium on which the ink has been ejected. This causes the moisture contained in the ink to evaporate, and the ink on the recording medium is dried. On the other hand, the humidity of the air that has dried the ink increases. However, according to the drying device described above, the air whose humidity has increased after being blown onto the recording medium passes through the dehumidification passage of the dehumidifying member, and is dehumidified in the process. Therefore, the release of high-humidity air from the drying device is prevented. Since high-humidity air is prevented from being drawn into the drying device, a decrease in the ink drying efficiency by the drying device can be suppressed. In addition, an increase in the humidity of the room in which the inkjet printer is installed can be suppressed. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a drying device that can maintain the drying efficiency of the ink and suppress the rise in humidity in the room in which the inkjet printer is installed, as well as an inkjet printer equipped therewith. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view of an inkjet printer equipped with a drying device according to one embodiment. [Figure 2] This is a simplified cross-sectional view of the section along line II-II in Figure 1. [Figure 3] This is a perspective view of the drying apparatus. [Figure 4] This is a perspective view of the dehumidifying component. [Figure 5] This is a cross-sectional view of the dehumidifying component. [Figure 6] This is a simplified front view showing the main components of an inkjet printer and drying apparatus. [Modes for carrying out the invention]

[0013] Hereinafter, an inkjet printer (hereinafter simply referred to as "printer") and a drying apparatus according to one embodiment of the present invention will be described with reference to the drawings.

[0014] Figure 1 is a perspective view of the printer 1 according to this embodiment. In the following description, the directions indicated by the symbols F, Rr, L, R, U, and D are forward, backward, left, right, up, and down, respectively. That is, left, right, up, and down mean left, right, up, and down as seen from the perspective of a user standing in front of the printer 1. The direction away from the printer 1 is considered forward, and the direction towards the printer 1 is considered backward. However, the directions defined here are merely defined directions for the sake of explanation and do not in any way limit the installation configuration of the printer 1. The symbol Y represents the direction of movement of the carriage 15, which will be described later, and will be referred to as the main scanning direction below. The symbol X represents the transport direction of the recording medium 5, which will be described later, and will be referred to as the sub-scanning direction below. Here, the sub-scanning direction X is perpendicular to the main scanning direction Y.

[0015] As shown in Figure 1, the printer 1 comprises a main body 10, legs 11 supporting the main body 10, an operation panel 12, and a front cover 13. An ink cartridge 7 containing ink is installed in the main body 10. The drying device 20 is located in front of the main body 10. The printer 1 is configured to eject ink onto a recording medium 5 and to form an image (including characters, etc.) on the recording medium 5 using the ink.

[0016] The type of ink is not particularly limited, but in this embodiment, it is an aqueous ink. As the aqueous ink, for example, latex ink can be preferably used. The latex ink contains a solvent, a colorant, and a binder resin. In the latex ink, the binder resin is dispersed or emulsion in the solvent. As the solvent, for example, one or more water-soluble organic solvents (lower alcohols, lower ketones, etc.) that can be uniformly mixed with water can be appropriately selected and used. The latex ink contains 50% to 90% by mass of the solvent based on the total mass of the latex ink. As the colorant, conventional colorants contained in latex ink can be appropriately selected. Examples of colorants include dyes such as water-soluble dyes and pigments. As the binder resin, conventional binder resins contained in latex ink can be appropriately selected.

[0017] The recording medium 5 is, for example, recording paper. However, the recording medium 5 is not limited to recording paper. In addition to paper such as plain paper and inkjet printing paper, the recording medium 5 includes those made from resin materials such as polyvinyl chloride (PVC) and polyester, as well as those made from metal plates made of aluminum or iron, glass plates, wooden boards, and corrugated cardboard.

[0018] FIG. 2 is a cross-sectional view schematically showing the main configurations of the printer 1 and the drying device 20, and is a cross-sectional view corresponding to the II-II cross section of FIG. 1. As shown in FIG. 2, inside the main body 10, there are provided a guide rail 14 extending in the main scanning direction Y, a carriage 15 slidably engaged with the guide rail 14, and an ink head 16 mounted on the carriage 15. Below the carriage 15, a platen 17 on which the recording medium 5 is placed is arranged. Although not shown in the figure, the carriage 15 is connected to a driving device and moves in the main scanning direction Y under the power of the driving device. Since the ink head 16 is mounted on the carriage 15, it can move in the main scanning direction Y together with the carriage 15. The ink head 16 is connected to an ink cartridge 7 (see FIG. 1) by a tube not shown. The ink head 16 is configured to discharge ink onto the recording medium 5 placed on the platen 17.

[0019] The platen 17 is provided with a drying plate 18 for heating the recording medium 5 immediately after the ink is discharged. The drying plate 18 is provided with a heating element composed of, for example, a heater. However, the drying plate 18 is not necessarily required and can be omitted.

[0020] An apron 19 is arranged in front of the platen 17. The recording medium 5 is conveyed from above the platen 17 onto the apron 19. The apron 19 extends downward (specifically, downward and forward) and supports the recording medium 5 onto which the ink has been discharged. The drying device 20 is arranged so as to face the apron 19. Specifically, the drying device 20 is arranged so as to face the recording medium 5 supported by the apron 19. Note that, in addition to drying by the drying device 20, a drying plate 18 may also be provided on the apron 19 to further promote drying. Next, the configuration of the drying device 20 will be described.

[0021] As shown in FIG. 2, the drying device 20 includes a casing 23 having an inlet 21 and an outlet 22 formed therein, a heater 24 disposed inside the casing 23, and a fan 25. FIG. 3 is a perspective view of the drying device 20. As shown in FIG. 3, the drying device 20 further includes a dehumidifying member 30.

[0022] As shown in FIG. 2, the inlet 21 is an opening for taking air from the outside to the inside of the casing 23. In the present embodiment, the inlet 21 opens upward (specifically, upward and rearward). The fan 25 is disposed above the inlet 21. The fan 25 is configured to send air from the outside to the inside of the casing 23 through the inlet 21. The number of fans 25 is not particularly limited, but in the present embodiment, as shown in FIG. 1, three fans 25 arranged in the main scanning direction Y are provided.

[0023] The heater 24 is an example of a heating element for heating air. The air taken into the inside of the casing 23 through the inlet 21 is heated by the heater 24. The air heated by the heater 24 is discharged to the outside of the casing 23 through the outlet 22. The outlet 22 opens toward the apron 19. Since the recording medium 5 is supported on the apron 19, the outlet 22 opens toward the recording medium 5 supported on the apron 19, that is, the recording medium 5 on which ink has been ejected. Here, the outlet 22 opens downward and rearward. The air heated by the heater 24 is discharged from the outlet 22 and blown onto the recording medium 5. Thereby, the ink on the recording medium 5 is heated, and the drying of the ink is promoted.

[0024] As shown in FIG. 2, a partition plate 23A extending downward (specifically, downward and rearward) is provided at the front end portion of the casing 23. A partition plate 23B extending downward (specifically, downward and rearward) is provided at the rear end portion of the casing 23. By these partition plates 23A and 23B, the air discharged from the outlet 22 and blown onto the recording medium 5 is configured to flow not upward and downward but leftward and rightward.

[0025] The dehumidifying member 30 dehumidifies the air blown onto the recording medium 5. The dehumidifying member 30 is located on the left and right sides of the casing 23. Figure 4 is a perspective view of the dehumidifying member 30. As shown in Figure 4, the dehumidifying member 30 comprises a plate 31, a plurality of cooling fins 32 located below the plate 31, and a plurality of heat dissipation fins 33 located above the plate 31. The plate 31, cooling fins 32, and heat dissipation fins 33 are preferably made of a material with relatively high thermal conductivity, and can be made of metals such as aluminum, iron, or copper. The plate 31, cooling fins 32, and heat dissipation fins 33 only need to be continuous with each other in a way that allows heat to conduct to each other, and may be separate from each other, but in this embodiment they are integrally formed. The plate 31, cooling fins 32, and heat dissipation fins 33 are made of a single article.

[0026] The cooling fins 32 extend downward (more specifically, downward and backward) from the plate 31. The cooling fins 32 also extend to the left and right. Dehumidification passages 34 are formed between adjacent cooling fins 32. The dehumidification passages 34 are passages that extend in the left-right direction. The heat dissipation fins 33 extend upward (more specifically, upward and forward) from the plate 31. The heat dissipation fins 33 also extend upward and downward. As shown in Figure 5 (note that the heater 24 is not shown in Figure 5), high-temperature air HA, which is discharged from the outlet 22 and blown onto the recording medium 5, flows through the dehumidification passages 34. The high-temperature air HA is cooled by the cooling fins 32. As a result, the moisture contained in the high-temperature air HA condenses, and the high-temperature air HA is dehumidified. On the other hand, the cooling fins 32 themselves are heated by the high-temperature air HA. The heat from the cooling fins 32 is transferred to the heat dissipation fins 33 through the plate 31. The heat dissipation fins 33 exchange heat with the surrounding air and release heat. In this way, the heat transferred from the high-temperature air HA to the cooling fins 32 is transferred sequentially through the cooling fins 32, plate 31, and heat dissipation fins 33, and is released from the heat dissipation fins 33.

[0027] As moisture contained in the high-temperature air HA condenses, drain (condensed water) is generated in the dehumidification passage 34. In this embodiment, a drain receiver 40 is positioned below the dehumidification passage 34 of the dehumidification member 30. The drain generated in the dehumidification passage 34 flows down into the drain receiver 40. As shown in Figure 4, a drain tube 41 for discharging the drain is connected to the drain receiver 40. As shown in Figure 5, the drain tube 41 connected to the left drain receiver 40 and the drain tube 41 connected to the right drain receiver 40 are connected to a drain recovery tank 42. The drain from the drain receiver 40 is collected in the drain recovery tank 42 through the drain tube 41. Note that, as shown in Figure 5, the left and right drain tubes 41 may merge before being connected to the drain recovery tank 42, or they may be connected to the drain recovery tank 42 individually. Alternatively, the drain recovery tank 42 connected to the left drain tube 41 and the drain recovery tank 42 connected to the right drain tube 41 may be provided separately.

[0028] The above describes the configuration of printer 1 and drying device 20. Next, the operation of printer 1 and drying device 20 will be explained.

[0029] In printer 1, the recording medium 5 is sequentially transported forward, and the ink head 16 moves in the main scanning direction Y, ejecting ink onto the recording medium 5 on the platen 17. The ink ejected from the ink head 16 onto the recording medium 5 is first heated on the platen 17 by the drying plate 18. This promotes the drying of the ink immediately after it lands on the recording medium 5.

[0030] The recording medium 5, which has been transported from the platen 17 onto the apron 19, is heated by the drying device 20. In the drying device 20, air from the surrounding area is drawn into the casing 23 through the intake port 21. This air is heated by the heater 24 and becomes high-temperature air. The high-temperature air is discharged from the exhaust port 22 and blown onto the recording medium 5 on the apron 19. As the high-temperature air is blown onto the recording medium 5, the ink on the recording medium 5 is heated and dried. At this time, the moisture in the ink evaporates, and the humidity of the high-temperature air HA that has dried the ink increases. The high-temperature air HA with increased humidity passes through the dehumidification passage 34 of the dehumidifying member 30 and is dehumidified by being cooled by the cooling fins 32. Dehumidified air is released around the drying device 20. The air surrounding the drying device 20 is drawn in again through the intake port 21, but dehumidified air is drawn in through the intake port 21.

[0031] As described above, according to the drying device 20 of this embodiment, the air blown onto the recording medium 5 and whose humidity has increased passes through the dehumidification passage 34 of the dehumidifying member 30 and is dehumidified at that time. Therefore, the air released from the drying device 20 is dehumidified air. According to this embodiment, it is possible to prevent the release of high-humidity air from the drying device 20. Therefore, according to this embodiment, it is possible to prevent high-humidity air from being drawn into the drying device 20, and thus it is possible to suppress a decrease in the drying efficiency of the ink. This makes it possible to avoid increasing the size and power consumption of the drying device 20. In addition, it is possible to suppress an increase in the humidity of the room in which the printer 1 is installed.

[0032] The drying device 20 is equipped with a dehumidifying member 30, but the dehumidifying member 30 only needs to be able to dehumidify the air, and its form is not particularly limited. For example, a desiccant such as silica gel may be used as the dehumidifying member 30, or a Peltier element may be used. However, when using a desiccant, the moisture absorption performance gradually decreases, so it needs to be replaced periodically. When using a Peltier element, an external power supply is required. On the other hand, according to this embodiment, the dehumidifying member 30 has a cooling fin 32 that forms at least a part of the dehumidifying passage 34, and a heat dissipation fin 33 that is continuously connected to the cooling fin 32 in a heat conduction manner and is provided outside the dehumidifying passage 34. Therefore, periodic replacement and an external power supply are unnecessary. Thus, maintenance costs can be reduced.

[0033] Furthermore, according to the drying apparatus 20 of this embodiment, a drain receiver 40 is positioned below the dehumidification passage 34 of the dehumidifying member 30. Therefore, the drain generated by dehumidifying the air after ink drying can be processed effectively.

[0034] According to this embodiment, the recording medium 5 is transported from top to bottom on the apron 19. Dehumidification passages 34 are provided on the left and right sides of the apron 19, with the left dehumidification passage 34 extending to the left from the left end of the apron 19 and the right dehumidification passage 34 extending to the right from the right end of the apron 19. Therefore, high-temperature air HA can be discharged to the left and right of the recording medium 5, and dehumidification can be performed at locations away from the recording medium 5 to the left and right. Thus, high-temperature air HA can be dehumidified without hindering the drying of the ink on the recording medium 5.

[0035] Furthermore, according to this embodiment, the cooling fins 32 of the dehumidifying member 30 extend to the left and right. Because the cooling fins 32 extend to the left and right, the high-temperature air HA can be discharged to the left or right while being dehumidified. Also, according to this embodiment, the heat dissipation fins 33 extend vertically. The heat dissipation fins 33 exchange heat with the air outside the dehumidifying passage 34 and heat the air. As the air heated by the heat dissipation fins 33 gets hotter, its specific gravity decreases. The air heated by the heat dissipation fins 33 tends to rise from the heat dissipation fins 33 due to natural convection. According to this embodiment, because the heat dissipation fins 33 extend vertically, it is less likely to hinder the rise of air due to natural convection. Therefore, natural convection around the heat dissipation fins 33 can be smoothed, and the heat dissipation efficiency of the heat dissipation fins 33 can be increased. As a result, the cooling efficiency of the cooling fins 32 can be increased, and the high-temperature air HA can be dehumidified effectively.

[0036] Although one embodiment of the present invention has been described above, this embodiment is merely an example, and various other embodiments are possible. Next, we will briefly describe some examples of other embodiments.

[0037] In the above embodiment, the intake port 21 is formed at the top of the casing 23 and opens upward, but the position and orientation of the intake port 21 are not particularly limited. The heating element of the drying apparatus 20 is not limited to the heater 24, but any means capable of heating air can be used as the heating element. The fan 25 only needs to be able to blow air so that air is drawn into the casing 23 from the intake port 21 and the air inside the casing 23 is discharged from the outlet port 22, and may be located outside the casing 23 as in the above embodiment, or it may be located inside the casing 23.

[0038] The cooling fins 32 may extend straight to the left and right, or they may extend straight in an upward or downward direction from the left and right directions. Furthermore, the cooling fins 32 do not necessarily have to extend to the left and right. The heat dissipation fins 33 do not necessarily have to extend vertically. The cooling fins 32 and heat dissipation fins 33 do not necessarily have to be formed in a flat plate shape; they may be formed in a curved or bent plate shape. The cooling fins 32 and heat dissipation fins 33 are not limited to plate fins; for example, they may be pin fins. The fin shape of the cooling fins 32 and heat dissipation fins 33 is not particularly limited.

[0039] If drain treatment is not required, or if drain treatment can be carried out by other means, the drain receiver 40 may be omitted.

[0040] The inkjet printer 1 does not necessarily have to have an apron 19 positioned in front of the platen 17. The drying device 20 only needs to be positioned so as to dry the ink on the recording medium 5, and does not necessarily have to be positioned opposite the apron 19. The inkjet printer is not limited to a roll-to-roll printer, but may also be a so-called flatbed printer or other types of printers.

[0041] The dehumidification passage 34 may be a straight passage or a curved passage. The direction in which the dehumidification passage 34 extends is not limited to left or right. [Explanation of Symbols]

[0042] 1. Inkjet printer 5. Recording media 16 Ink Heads 17 Platen 19 Apron 20 Drying equipment 21 Inlet 22 Outlet 23 Casing 24 Heater (heating element) 25 Fans 30 Dehumidifying component 32 cooling fins 33 heat dissipation fins 34 Dehumidification passage 40 Drain receiver

Claims

1. A platen on which the recording medium is placed, An ink head that ejects ink onto the recording medium placed on the platen, An apron extending downward to support the recording medium from which ink has been ejected, Equipped with a drying device, The drying apparatus is A casing having an intake port and an outlet port that opens toward the recording medium from which the ink has been ejected, A heating element disposed inside the casing, A fan blows air into the casing from the intake port and discharges the air inside the casing from the exhaust port. The dehumidifying member comprises a dehumidifying passage that allows air discharged from the outlet and blown onto the recording medium to pass through while being dehumidified, The drying apparatus is an inkjet printer in which the discharge port is positioned to face the recording medium on the apron.

2. The inkjet printer according to claim 1, wherein the dehumidifying member comprises cooling fins that form at least a portion of the dehumidifying passage, and heat dissipation fins that are continuously connected to the cooling fins in a heat conduction manner and provided outside the dehumidifying passage.

3. The inkjet printer according to claim 1 or 2, wherein the drying device is provided with a drain receiver located below the dehumidifying passage of the dehumidifying member.

4. The inkjet printer according to any one of claims 1 to 3, wherein the dehumidifying passage of the drying apparatus extends to the left from the left end of the apron, or extends to the right from the right end of the apron.

5. The inkjet printer according to claim 2, wherein the cooling fins extend to the left and right, and the heat dissipation fins extend up and down.

Images