JP7435013B2 - Degassing device, degassing method, and inkjet recording device - Google Patents

Description

The present invention relates to a degassing device, a degassing method, and an inkjet recording device.

2. Description of the Related Art Conventionally, inkjet recording apparatuses that form images and the like by ejecting ink onto a recording medium from nozzles provided in an inkjet head have been widely used. In an inkjet recording device, if the ink supplied from the ink flow path to the ink ejection head contains gas, the pressure applied when ejecting the ink will not be properly transmitted to the ink, resulting in ink ejection failure. This may occur. Therefore, there is a technique for suppressing the occurrence of ink ejection failure by providing a degassing section that removes gas from the ink supplied to the ink ejection head (for example, Patent Document 1).

Most degassing units remove gas in the ink by bringing one side of a gas-permeable degassing membrane into contact with the ink in the ink flow path and bringing the other side of the degassing membrane into contact with a vacuum path. It is designed to be drawn into a vacuum path and released. However, the gas desorbed from the ink is mixed with liquid components (for example, monomers) of the ink that seeped out from the degassing membrane. Therefore, in the middle of the vacuum path, a trap is provided to store the liquid component of the ink mixed with the gas so that it does not enter the vacuum pump that keeps the vacuum path in a vacuum state. There is.

JP2010-58413A

In the conventional technique disclosed in Patent Document 1, as described below, the liquid component of the ink mixed with the gas sometimes sticks inside the path connecting the degassing section and the trap.

For example, in an inkjet recording apparatus, a path (hereinafter referred to as a "connection path") connecting a degassing section and a trap in a vacuum path is a portion that is relatively easily cooled. Therefore, when the liquid component of the ink mixed with the gas passes through the inside of the connection path together with the gas, the temperature of the liquid component decreases, and the liquid component sometimes solidifies and sticks inside the connection path. The connection path is formed to have a relatively small diameter. Therefore, the connection path may become clogged by the liquid component of the fixed ink.

The present invention has been made in view of the problems of the prior art described above, and an object of the present invention is to prevent the liquid component of the ink mixed with the gas from sticking inside the path connecting the degassing section and the trap. It is an object of the present invention to provide a degassing device, a degassing method, and an inkjet recording device.

The above-mentioned problems of the present invention are solved by the following means.

(1) A degassing device used in an inkjet recording device, which includes a degassing section that desorbs gas from ink flowing through an ink flow path, a vacuum path through which the gas desorbed in the degassing section flows, and the vacuum A trap provided on the path for storing a liquid component of the ink mixed in the gas, and a heating means for heating a connection path connecting the degassing section and the trap in the vacuum path. , wherein the heating means is a heat transfer member that transfers heat from the deaeration section to the connection path, and the heat transfer member has a thermal conductivity of 100 W/m·K or more. Device.
(2) A degassing device used in an inkjet recording device, which includes a degassing section that degasses gas from ink flowing through an ink flow path, a vacuum path through which the gas desorbed in the degassing section flows, and the vacuum A trap provided on the path for storing a liquid component of the ink mixed in the gas, and a heating means for heating a connection path connecting the degassing section and the trap in the vacuum path. , the liquid component of the ink is sucked from the degassing section by a vacuum pump connected to the vacuum path with the atmospheric path connecting the inside of the degassing section and the outside at atmospheric pressure open to the atmosphere. A deaerator characterized in that the gas is collected in the trap.

( 3 ) The degassing device according to (1) or (2) above, wherein the heating means heats the connection path to a temperature equal to or higher than the melting point of the liquid component of the ink.

( 4 ) The deaerator according to (2) above, wherein the heating means is a heater.

( 5 ) The deaerator according to (1) above, wherein the housing of the deaerator has a thermal conductivity of 100 W/m·K or more.

( 6 ) The ink according to any one of (1) to ( 5 ) above, wherein the ink has a viscosity of 7 centipoise or more when ejected from an ink ejection head that ejects the ink. Deaerator.

( 7 ) The degassing section has a tubular hollow fiber membrane, and while degassing the ink with the hollow fiber membrane, fills the outside of the hollow fiber membrane with the deaerated ink. The deaerator according to any one of (1) to ( 6 ) above.

( 8 ) The deaerator according to any one of (1) to ( 7 ) above, wherein the connection path is connected to an upper part of the trap.

( 9 ) The deaerator according to any one of (1) to ( 8 ) above, wherein the trap is disposed near the deaerator.

( 10 ) A deaeration method used in an inkjet recording device, in which a connection path connecting a deaeration unit that desorbs gas from ink and a trap that stores a liquid component of ink contained in the gas is A deaeration method characterized by heating the deaeration section by transmitting heat from the deaeration section to the connection path using a heat transfer member having a thermal conductivity of mK or more .
(11) A degassing method used in an inkjet recording device, which heats a connection path connecting a degassing section that desorbs gas from ink and a trap that stores liquid components of ink mixed in the gas, and The liquid component of the ink is produced by a vacuum pump connected to a vacuum path through which the gas desorbed in the degassing section flows, with the atmospheric path connecting the inside of the degassing section and the outside at atmospheric pressure being open to the atmosphere. A deaeration method characterized in that the deaeration method is collected in the trap by suction from the deaeration section.

( 12 ) An inkjet recording apparatus, comprising: a deaerator according to any one of (1) to ( 9 ) above; and an ink ejection head to which ink degassed by the deaerator is supplied; An inkjet recording apparatus comprising: a nozzle provided in the inkjet head to eject the ink to form an image on a recording medium.

According to the present invention, it is possible to suppress the liquid component of the ink mixed into the gas from sticking inside the path connecting the degassing section and the trap.

1 is a schematic configuration diagram of an inkjet recording apparatus including a degassing device according to an embodiment. FIG. 2 is a schematic configuration diagram of the vicinity of an ink head unit of an inkjet recording apparatus. It is a schematic block diagram of a deaerator. It is a schematic block diagram of the vicinity of the degassing part of the degassing device. FIG. 2 is an internal block diagram of an inkjet recording device. 3 is a flowchart showing the operation of the inkjet recording apparatus. It is a figure which shows the modification of the heating means of a deaerator.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that each figure is merely shown schematically to the extent that the present invention can be fully understood. Therefore, the present invention is not limited to the illustrated example. Further, in each figure, common or similar components are denoted by the same reference numerals, and redundant explanation thereof will be omitted.

<Configuration of inkjet recording device>
Hereinafter, with reference to FIG. 1, the configuration of an inkjet recording apparatus 1 including a deaerator 2 according to this embodiment will be described. FIG. 1 is a schematic configuration diagram of an inkjet recording apparatus 1 including a deaerator 2 according to the present embodiment.

As shown in FIG. 1, an inkjet recording apparatus 1 including a deaerator 2 according to the present embodiment includes a paper feed section 10, an image recording section 20, a paper discharge section 30, and a control section 60. The inkjet recording apparatus 1 conveys the recording medium P stored in the paper feed section 10 to the image recording section 20 under the control of the control section 60, records an image on the recording medium P in the image recording section 20, and records the image on the recording medium P. The recorded recording medium P is conveyed to the paper discharge section 30.

As the recording medium P, in addition to paper such as plain paper or coated paper, various media capable of solidifying ink ejected onto the surface, such as cloth or sheet-like resin, can be used.

The paper feeding section 10 is a mechanism that supplies the recording medium P to the image recording section 20. The paper feed section 10 includes a paper feed tray 11 that stores the recording medium P, and a medium supply section 12 that transports and supplies the recording medium P from the paper feed tray 11 to the image recording section 20. The medium supply unit 12 includes a ring-shaped belt stretched between two rollers, and conveys the recording medium P by rotating the rollers with the recording medium P placed on the belt.

The image recording unit 20 is a mechanism that records an image on the recording medium P. The image recording section 20 includes a transport drum 21 (transport section), a delivery unit 22, a paper heating section 23, an ink head unit 24, a fixing section 25, and a delivery section 26.

The transport drum 21 is a member that transports the recording medium P. The conveyance drum 21 has a cylindrical shape, and extends in a direction perpendicular to the plane of the paper in FIG. By rotating around the rotation axis, the recording medium P is conveyed in the conveyance direction along the conveyance surface 21a. The transport drum 21 is connected to a transport drum motor (not shown) for rotating the transport drum 21, and rotates by an angle proportional to the amount of rotation of the transport drum motor.

The delivery unit 22 is a unit that delivers the recording medium P transported by the medium supply section 12 of the paper feed section 10 to the transport drum 21. The delivery unit 22 is provided between the medium supply section 12 of the paper supply section 10 and the transport drum 21. The delivery unit 22 includes a swing arm section 221 that delivers the recording medium P from the medium supply section 12 to the delivery drum 222, and a delivery drum 222 that delivers the recording medium P to the transport drum 21.

The paper heating section 23 is a mechanism that heats the recording medium P. The paper heating section 23 is provided between the placement position of the delivery drum 222 and the placement position of the ink head unit 24. The paper heating unit 23 heats the recording medium P so that the temperature of the recording medium P conveyed by the conveyance drum 21 falls within a predetermined range.

The ink head unit 24 is a unit that records (forms) an image by ejecting ink onto the recording medium P. The ink head unit 24 ejects ink onto the recording medium P at an appropriate timing according to the rotation of the conveyance drum 21 holding the recording medium P based on a print instruction from the external device 9 (see FIG. 5). This will record the image. In this embodiment, the four ink head units 24 respectively corresponding to the four colors of ink of yellow, magenta, cyan, and black are arranged in the predetermined order of yellow, magenta, cyan, and black from the upstream side in the conveyance direction of the recording medium P. They are arranged so that they are spaced apart.

The fixing section 25 has a light emitting section that is arranged to face the conveying drum 21 in the width direction, and emits energy rays such as ultraviolet rays from the light emitting section to the recording medium P placed on the conveying drum 21. The ink ejected onto the recording medium P by irradiation is cured and fixed.

The delivery unit 26 includes a belt loop 262 having a ring-shaped belt whose inner side is supported by two rollers, and a cylindrical delivery drum 261 that delivers the recording medium P from the transport drum 21 to the belt loop 262. The recording medium P transferred from the conveyance drum 21 onto the belt loop 262 by the transfer drum 261 is conveyed by the belt loop 262 and sent to the paper discharge section 30 .

The paper discharge section 30 has a plate-shaped paper discharge tray 31 on which the recording medium P sent out from the image recording section 20 by the delivery section 26 is placed.

<Configuration near the ink head unit>
Hereinafter, the configuration around the ink head unit 24 will be described with reference to FIG. 2. FIG. 2 is a schematic diagram of the vicinity of the ink head unit 24. FIG. 2 shows a schematic internal configuration of the ink head unit 24 when viewed from the front.

As shown in FIG. 2, the ink head unit 24 includes a housing 24a and a plurality of (six in the illustrated example) ink ejection heads 240 (recording heads) housed inside the housing 24a. The ink ejection head 240 is a mechanism that ejects ink to form an image on a recording medium.

At the bottom of the ink ejection head 240, a plurality of nozzles (not shown) for ejecting ink are arranged along the width direction. The nozzles of the ink ejection head 240 are arranged so as to protrude downward from the lower surface of the housing 24a so that the opening faces face the transport surface 21a of the transport drum 21.

Each ink discharge head 240 has an inlet 240a through which ink supplied into the ink discharge head 240 flows, an outlet 240b through which ink discharged from the ink discharge head 240 flows out, and an ink discharge head 240 in which ink is supplied into the ink discharge head 240. and an ink heating section 240c that heats the ink. The ink head unit 24 is provided with an ink flow path 242 through which ink is supplied to the inlet 240a and ink is discharged from the outlet 240b. However, in FIG. 2, the ink flow path 242 connected to the outlet 240b is omitted. A solid arrow indicates the flow direction of ink flowing within the ink flow path 242 (the same applies hereinafter).

A degassing module 41 (degassing section) is provided inside the casing 24a of the ink head unit 24 to remove (degassing) the gas in the ink flowing through the ink flow path 242. The degassing module 41, together with a trap 42 and a vacuum path 44, which will be described later, constitutes a degassing device 2 that desorbs gas in the ink. The inkjet recording apparatus 1 can properly transmit the pressure applied when the ink is ejected from the ink ejection head 240 to the ink by desorbing the gas in the ink using the degassing module 41.

The degassing module 41 is connected to a vacuum pump 51 via a vacuum path 44 . The vacuum pump 51 is a vacuum suction unit that sucks gas (air) inside the degassing module 41 and the vacuum path 44 . The vacuum pump 51 is provided outside the ink head unit 24. The gas is guided through the vacuum path 44 to the vacuum pump 51, and is exhausted to the outside through the vacuum pump 51. The dotted arrow indicates the flow direction of gas flowing within the vacuum path 44 (the same applies hereinafter). Although the vacuum path 44 is not particularly limited, for example, a silicon tube or the like can be used.

A trap 42 is provided in the middle of the vacuum path 44 to collect and store the liquid component of the ink so that the liquid component of the ink mixed with the gas does not enter the vacuum pump 51. The trap 42 is provided inside the housing 24a of the ink head unit 24 near the degassing module 41 (for example, within 30 cm). The trap 42 is fixed in a state where it is fitted into a through hole provided on the lower surface of the housing 24a.

The ink ejected from the ink ejection head 240 is, for example, an ink whose monomer polymerizes and hardens when irradiated with ultraviolet rays, and when it is not irradiated with ultraviolet rays, it changes between a gel state and a sol state depending on the temperature. Ink having the property of changing its phase between two colors (phase change ink) is used. Here, it is assumed that a gel state is included in a solid, and a sol state is included in a liquid. This ink uniformly liquefies (solizes) when heated above a predetermined phase change temperature (for example, about 40°C to 60°C), while it can be heated to about normal room temperature (about 0°C to 30°C). It gels in a temperature range below the phase change temperature.

In this embodiment, the ink heating section 240c provided in the ink ejection head 240 heats the ink to a temperature at which it becomes a sol, and the ink in the sol state is ejected from the nozzle. The ink ejected from the nozzle and landing on the recording medium P is cooled to room temperature and quickly becomes a gel state.

The degassing module 41 (degassing unit) is provided in the middle of the ink flow path 242, and is equipped with a degassing membrane 41e (hollow fiber membrane) (see FIG. 4) that desorbs gas in the ink. There is.

<Configuration of deaerator>
Hereinafter, a schematic configuration of the deaerator 2 will be described with reference to FIGS. 3 and 4. FIG. 3 is a schematic configuration diagram of the deaerator 2. As shown in FIG. FIG. 4 is a schematic diagram of the vicinity of the degassing module 41 (degassing section) of the degassing device 2. As shown in FIG.

As shown in FIG. 3, the degassing device 2 includes the degassing module 41 described above, the trap 42 described above, and the vacuum path 44 described above. One deaerator 2 is provided for each ink head unit 24. Note that in FIG. 3, only one of the plurality of ink ejection heads 240 (see FIG. 2) provided in the ink head unit 24 is shown as a representative.

The ink head unit 24 includes a first sub-tank 241, the degassing module 41 described above, a circulation pump 243, a second sub-tank 245, and the ink ejection head 240 described above.

The first sub tank 241 is a small storage section that temporarily stores ink to be supplied to the ink ejection head 240.
The circulation pump 243 is a pump for sending the ink degassed by the deaeration module 41 to the second sub-tank 245.

The second sub-tank 245 is a small storage section that temporarily stores ink that has been degassed by the deaeration module 41. The ink stored in the second sub-tank 245 is supplied to each ink ejection head 240. The second sub-tank 245 is sealed except for the connection point with the ink flow path 242. The capacity of the second sub-tank 245 is not particularly limited, but a capacity similar to that of the first sub-tank 241 is used.

An ink supply section 27 is provided outside the ink head unit 24. The ink supply section 27 includes a main tank 271 and a supply pump 272.

The main tank 271 is a storage section that stores ink of a color corresponding to the ink head unit 24. The capacity of the main tank 271 is not particularly limited, but one with a large capacity of, for example, several liters to several tens of liters is used.
The supply pump 272 is a pump for feeding ink stored in the main tank 271 to the first sub-tank 241 in the ink head unit 24 .

Further, the above-mentioned vacuum pump 51 is provided outside the ink head unit 24.

Ink flows inside the ink channel 242. In this embodiment, the ink flow path 242 has a configuration including a first flow path 242a, a second flow path 242b, a third flow path 242c, a fourth flow path 242d, and a fifth flow path 242e. It has become.

The first flow path 242a is a flow path that connects the main tank 271 and the first sub tank 241. The above-mentioned supply pump 272 is provided in the middle of the first flow path 242a.
The second flow path 242b is a flow path that connects the first sub-tank 241 and the degassing module 41.

The third flow path 242c is a flow path that connects the degassing module 41 and the second sub-tank 245. The above-mentioned circulation pump 243 and check valve 244 are provided in the middle of the third flow path 242c. The check valve 244 prevents the ink sent from the deaeration module 41 to the second sub-tank 245 from flowing back. The ink degassed by the deaeration module 41 is sent to the second sub-tank 245 via the check valve 244 by the circulation pump 243.

The fourth flow path 242d is a flow path that connects the second sub-tank 245 and the ink ejection head 240. The fourth flow path 242d is connected to the inlet 240a of each ink ejection head 240. Each ink ejection head 240 receives ink supply from the second sub-tank 245 via the fourth flow path 242d.

The fifth flow path 242e is a flow path that connects the ink ejection head 240 and the first sub-tank 241. The fifth flow path 242e is connected to the outlet 240b of each ink ejection head 240. Each ink ejection head 240 returns a portion of the ink that is not ejected onto the recording medium P to the first sub-tank 241 via the fifth flow path 242e. A valve 246 is provided in the middle of the fifth flow path 242e. The valve 246 adjusts the amount of ink that is returned from the ink ejection head 240 to the first sub tank 241.

The second flow path 242b to the fifth flow path 242e of the ink flow path 242 circulate ink from the first sub-tank 241, through the degassing module 41, the second sub-tank 245, the ink ejection head 240, and back to the first sub-tank 241. forming a route.

Furthermore, the gas desorbed from the ink by the degassing module 41 flows inside the vacuum path 44 . In this embodiment, the vacuum path 44 includes a connection path 44a and a communication path 44b. The connection path 44a is a flow path that connects the degassing module 41 and the trap 42. The communication path 44b is a flow path that connects the trap 42 and the vacuum pump 51.

The ink in the ink ejection head 240 is heated by the ink heating section 240c and becomes a sol. Further, the ink in the first sub-tank 241, the degassing module 41, and the second sub-tank 245 is also heated by an ink heating unit (not shown) provided in each of them, and becomes a sol.

The degassing module 41 is connected to an atmospheric path 45 that communicates with atmospheric space. An atmosphere communication valve 451 is provided in the middle of the atmosphere path 45. The atmosphere communication valve 451 is a valve mechanism that selectively opens or closes the atmosphere path 45.

Degassing module 41 is connected to trap 42 and vacuum pump 51 via vacuum path 44 . The degassing device 2 opens the atmospheric communication valve 451 to open the atmospheric path 45 to the atmosphere in order to facilitate the flow of the gas separated from the ink during degassing, and the vacuum pump 51 opens the atmospheric path 45 to the atmosphere. A suction operation is performed to suck the air inside 44. As a result, gas is desorbed from the ink in the degassing module 41 , and the desorbed gas flows through the vacuum path 44 . The vacuum pump 51 does not necessarily have to bring the inside of the vacuum path 44 to an ultra-high vacuum state, but reduces the pressure to the extent necessary for degassing.

Note that the degassing module 41 is provided in each of the four ink head units 24 of yellow, magenta, cyan, and black. On the other hand, only one vacuum pump 51 is provided in common to the four ink head units 24 of yellow, magenta, cyan, and black.

As shown in FIG. 4, the degassing module 41 has a structure in which a central tube 41b is covered with a degassing membrane 41e (hollow fiber membrane) inside an outer shell 41a (housing). The degassing membrane 41e is a tubular gas-permeable membrane body composed of a large number of hollow fibers. The degassing membrane 41e has a structure of a large number of hollow fine threads with one end closed, and its membrane surface has gas permeability. The center tube 41b is formed of a circular tube. The upper and lower parts of the degassing membrane 41e are held by a silicon cap 41f and a silicon cap 41g. One end of the central tube 41b is connected to a second flow path 242b of the ink flow path 242. Further, the other end of the central tube 41b is sealed with a plug 41c. A plurality of small holes 41d (perforations) are provided in the outer wall of the central tube 41b.

The ink that has flowed into the center tube 41b from the second flow path 242b of the ink flow path 242 flows out around the center tube 41b through the narrow hole 41d and passes through the degassing membrane 41e. At this time, the ink is degassed by the degassing membrane 41e. During degassing, the outer shell 41a (housing) of the degassing module 41 is heated to a temperature higher than the melting point of the liquid component of the ink (e.g., 60°C or higher) using a heater (not shown) to facilitate the flow of the ink. ) is heated.

The ink that has passed through the degassing membrane 41e is stored in a space SP1 provided around the degassing membrane 41e. The space SP1 is a space provided around the degassing membrane 41e inside the outer shell 41a (housing) and sandwiched between the silicon cap 41f and the silicon cap 41g at the top and bottom. Such a degassing module 41 is configured to degas the ink using the degassing membrane 41e while filling the outside of the degassing membrane 41e with the degassed ink.

One end of the third flow path 242c of the ink flow path 242 is inserted into the space SP1. The ink stored in the space SP1 is sent to the second sub-tank 245 (see FIG. 3) by the circulation pump 243 (see FIG. 3) via the third flow path 242c of the ink flow path 242.

Inside the outer shell 41a (housing), a space SP2 is provided above the silicone cap 41f, and a space SP3 is provided below the silicone cap 41g. Air introduced from the atmosphere to the degassing module 41 via the atmospheric path 45 is stored in the space SP2. Gas released from the ink by the degassing membrane 41e is stored in the space SP3.

An atmospheric path 45 is connected to the space SP2. On the other hand, a connection path 44a of the vacuum path 44 is connected to the space SP3.

As described above, in order to facilitate the flow of the gas separated from the ink during degassing, the deaerator 2 opens the atmosphere communication valve 451 to open the atmosphere path 45 to the atmosphere, and operates the vacuum pump. At 51, a suction operation is performed to suction the air within the vacuum path 44. At this time, the pressure inside the fine thread structure of the degassing membrane 41e is reduced. In this state, when the ink comes into contact with the membrane surface of the degassing membrane 41e, the gas in the ink selectively permeates the membrane surface, and the gas is degassed from the ink. The desorbed gas flows through the vacuum path 44 through the space SP3.

At this time, normally, a small amount of the liquid component (mainly monomer) of the ink passes through the degassing membrane 41e together with the gas component and seeps into the space SP3 which is depressurized by the vacuum pump 51. As a result, the liquid component of the ink mixed with gas may leak from the space SP3 to the connection path 44a of the vacuum path 44. If the liquid component of the ink enters the vacuum pump 51, there is a possibility that the vacuum pump 51 will malfunction.

Therefore, as described above, a trap 42 is provided in the middle of the vacuum path 44 to collect and store the liquid component of the ink so that the liquid component of the ink mixed with the gas does not enter the vacuum pump 51. It is being The trap 42 has, for example, a small tank-like shape. Inside the trap 42, the liquid component of the ink leaked from the degassing membrane 41e of the degassing module 41 is stored. Since the amount of the liquid component of the ink leaking from the degassing membrane 41e is about several cc per day, the trap 42 is used, for example, about several tens of cc. The trap 42 is configured to be attachable to and detachable from the vacuum path 44. Once the liquid component of the ink is stored, the trap 42 is removed from the vacuum path 44 at an arbitrary timing, cleaned, and then reattached to the vacuum path 44 .

By the way, the connection path 44a and the communication path 44b of the vacuum path 44 are configured to cool relatively easily. Therefore, when the liquid component of the ink mixed with the gas passes through the inside of the connection path 44a, the temperature of the liquid component increases as the liquid component advances from the degassing module 41, which is heated by a heater (not shown), toward the vacuum pump 51. It will drop. As a result, the liquid component solidifies inside the connection path 44a, and the liquid component tends to stick inside the connection path 44a.

In particular, in the inkjet recording apparatus 1, high viscosity ink may be used to suppress ink scattering when ejected from the ink ejection head 240 onto the recording medium P. Here, "high viscosity ink" is, for example, ink whose viscosity at the time of head ejection (viscosity at the time of ejection from the ink ejection head 240) is 7 cP (centipoise) or more (preferably 8 cP or more).

Regarding this point, for example, when the recording medium P is a medium that easily repels ink, such as glossy paper, when the inkjet recording apparatus 1 ejects ink from the ink ejection head 240 onto the recording medium P, the ink lands on the recording medium P. Sometimes the ink splatters and sticks together. Since the high-viscosity ink reliably adheres to the recording medium P when it lands on the recording medium P, scattering can be suppressed.

The liquid component of the ink, which has a high viscosity, tends to solidify as the temperature decreases. Furthermore, ink with high viscosity often contains a gel component in order to achieve high viscosity, but the gel component is particularly easy to solidify. Therefore, when the liquid component of the ink with high viscosity passes through the inside of the connection path 44a, the liquid component becomes more likely to stick inside the connection path 44a. The connection path 44a is formed to have a relatively small diameter. Therefore, there is a possibility that the connection path 44a may become clogged with the liquid component of the fixed ink.

Therefore, the deaerator 2 according to this embodiment includes a heater 46 near the connection path 44a. The heater 46 is a heating means that heats the connection path 44a. As the heater 46, for example, a configuration in which a heating wire such as a nichrome wire is energized to generate heat can be used. The heater 46 heats the connection path 44a (particularly the portion where the liquid component of the ink is likely to solidify) to a temperature equal to or higher than the melting point of the liquid component of the ink (for example, a temperature of 60° C. or higher). The heater 46 constantly heats the connection path 44a while the inkjet recording apparatus 1 is powered on. Note that the upper limit of the heating temperature of the heater 46 is preferably set to a temperature lower than the boiling point of the liquid component of the ink so that the liquid component of the ink does not vaporize and exceed the trap 42.

Such a deaerator 2 can prevent the liquid component of the ink from solidifying inside the connection path 44a by heating the connection path 44a with the heater 46 as a heating means. Therefore, the deaerator 2 can suppress the liquid component of the ink from sticking inside the connection path 44a. Thereby, the deaerator 2 can prevent the connection path 44a from being clogged with the liquid component of the ink.

<Internal configuration of inkjet recording device>
The internal configuration of the inkjet recording apparatus 1 will be described below with reference to FIG. 5. FIG. 5 is an internal block diagram of the inkjet recording apparatus 1. As shown in FIG.

As shown in FIG. 5, the inkjet recording apparatus 1 includes a deaerator 2 having the above-described supply pump 272, circulation pump 243, vacuum pump 51, ink heating section 240c, and atmosphere communication valve 451; It includes a paper heating section 23 and a fixing section 25. The inkjet recording apparatus 1 also includes a control section 60 having a CPU 61 (Central Processing Unit) (recording control means), a RAM 62 (Random Access Memory), a ROM 63 (Read Only Memory), and a storage section 64, and an ink ejection head control section 71. , a head unit movement drive section 72 , a transport drive section 73 , an input/output interface 74 , and a bus 75 .

The CPU 61 reads various control programs and setting data stored in the ROM 63, stores them in the RAM 62, and executes the programs to perform various calculation processes. The CPU 61 thereby centrally controls the entire operation of the inkjet recording apparatus 1.

The RAM 62 provides a working memory space for the CPU 61 and stores temporary data.
RAM 62 may include nonvolatile memory.

The ROM 63 stores various control programs executed by the CPU 61, setting data, and the like. Note that in place of the ROM 63, a rewritable nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used.

The storage unit 64 stores a print job (image recording command) input from the external device 9 via the input/output interface 74, image data related to the print job, and the like. As the storage unit 64, for example, an HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may also be used in combination.

The ink ejection head control section 71 outputs various control signals and image data to the head drive section provided in the ink ejection head 240 at appropriate timings according to control signals from the control section 60.

The head unit movement drive section 72 moves the ink head unit between a position where the opening of the nozzle faces the transport surface 21a of the transport drum 21 and a position where it does not face the transport surface 21a, according to a control signal from the control section 60. Move 24.

The conveyance drive section 73 supplies a drive signal to a conveyance drum motor (not shown) of the conveyance drum 21 based on a control signal supplied from the control section 60, and rotates the conveyance drum 21 at a predetermined speed and timing. Further, the conveyance drive section 73 supplies a drive signal to a motor (not shown) for operating the medium supply section 12, the transfer unit 22, and the delivery section 26 based on the control signal supplied from the control section 60, and performs recording. The medium P is supplied to the transport drum 21 and discharged from the transport drum 21.

The input/output interface 74 is a means for transmitting and receiving data to and from the external device 9.
The bus 75 is a path for transmitting and receiving signals between the control unit 60 and other components.
The external device 9 is, for example, a personal computer, and supplies print instructions (print job, image data, etc.) to the control unit 60 via the input/output interface 74.

<Operation of an inkjet recording device equipped with a deaerator>
Hereinafter, with reference to FIG. 6, the operation of the inkjet recording apparatus 1 including the deaerator 2 will be described. FIG. 6 is a flowchart showing the operation of the inkjet recording apparatus 1.

As shown in FIG. 6, the inkjet recording apparatus 1 starts heating the connection path 44a when the power is turned on (step S110). The connection path 44a is continuously heated while the power is turned on.

Then, the inkjet recording apparatus 1 waits for a print instruction to be output from the external device 9 while heating the connection path 44a, and when the print instruction is output from the external device 9, accepts the print instruction (step S120 ).

Then, the inkjet recording apparatus 1 supplies ink and performs a degassing process (step S130). In the degassing process, the atmospheric communication valve 451 is opened to open the atmospheric path 45 to the atmosphere (step S130a), and the vacuum pump 51 connected to the vacuum path 44 sucks gas from the degassing module 41 (step S130b). ). At this time, the liquid component of the ink mixed with the gas is sucked together with the gas by the vacuum pump 51 and flows into the vacuum path 44 . When the liquid component of the ink passes through the trap 42, it is collected by the trap 42 and recovered.

Then, the inkjet recording apparatus 1 executes printing (step S140). When printing is completed, the inkjet recording apparatus 1 enters a standby state and waits for the next print instruction to be output from the external device 9.

<Main features of the deaerator>
The deaerator 2 according to this embodiment has the following features.
(1) As shown in FIG. 4, the degassing device 2 according to the present embodiment includes a degassing module 41 (degassing section) that desorbs gas from the ink flowing through the ink flow path 242; A vacuum path 44 through which the desorbed gas flows, a trap 42 that is provided on the vacuum path 44 and stores the liquid component of the ink mixed in the gas, and a degassing module 41 and a trap 42 of the vacuum path 44. A heating means (heater 46 in this embodiment) is provided to heat the connection path 44a.

The deaerator 2 according to the present embodiment heats the connection path 44a with the heater 46 as a heating means, so that the liquid component of the ink is fixed inside the connection path 44a. can be restrained from doing so. Thereby, the deaerator 2 can prevent the connection path 44a from being clogged with the liquid component of the ink.

(2) The heating means of the degassing device 2 according to the present embodiment may heat the connection path 44a to a temperature equal to or higher than the melting point of the liquid component of the ink (for example, a temperature equal to or higher than 60° C.). In this embodiment, the heating means includes a heater 46.

The degassing device 2 according to this embodiment can prevent the liquid component of the ink from solidifying inside the connection path 44a.

(3) The ink used in the degassing device 2 according to the present embodiment preferably has a viscosity of 7 cP (centipoise) or more when ejected from the ink ejection head 240 that ejects the ink.

Since such ink reliably adheres to the recording medium P when it lands on the recording medium P, scattering when ejected onto the recording medium P can be suppressed.

(4) As shown in FIG. 4, the degassing module 41 of the degassing device 2 according to the present embodiment has a tubular degassing membrane 41e (hollow fiber membrane), and the degassing membrane 41e degasses ink. It is preferable that the outside of the degassing film 41e be carefully filled with degassed ink.

The degassing device 2 according to this embodiment can supply the degassed ink filled outside the degassing membrane 41e to the ink ejection head.

(5) As shown in FIG. 4, the connection path 44a of the deaerator 2 according to this embodiment is preferably connected to the upper part of the trap 42.

The degassing device 2 according to this embodiment efficiently removes the liquid component of the ink by sending the liquid component of the ink together with the gas into the upper part of the trap 42 and causing the liquid component of the ink to fall inside the trap 42. It can be collected.

(6) As shown in FIG. 6, in the degassing device 2 according to the present embodiment, the liquid component of the ink is in a state where the atmospheric path 45 connecting the inside of the degassing module 41 and the outside at atmospheric pressure is opened to the atmosphere. It is preferable that the gas is sucked from the degassing module 41 by a vacuum pump 51 connected to the vacuum path 44 and collected in the trap 42 .

The degassing device 2 according to this embodiment can take outside air (air) into the degassing module 41 from the atmospheric path 45 during degassing. Therefore, the deaerator 2 can cause the liquid component of the ink to flow smoothly by sucking the liquid component of the ink together with the gas using the vacuum pump 51, and can efficiently collect the liquid component in the trap 42.

(7) As shown in FIG. 3, the trap 42 of the deaerator 2 according to this embodiment is preferably placed near the deaerator module 41 (for example, within 30 cm).

In the degassing device 2 according to this embodiment, the distance between the trap 42 and the degassing module 41 is short, so the length of the connection path 44a can be shortened. As a result, the deaerator 2 can reduce the amount of heat dissipated through the connection path 44a, making it difficult to lower the temperature of the liquid component of the ink passing through the connection path 44a. As a result, the deaerator 2 can reduce the power consumption of the heating means (heater 46 in this embodiment).

As described above, according to the degassing device 2 according to the present embodiment, the liquid component of the ink mixed with the gas does not stick inside the connection path 44a that connects the degassing module 41 (degassing section) and the trap 42. can be suppressed.

Note that the present invention is not limited to the embodiments described above, and various changes and modifications can be made without departing from the gist of the present invention.

For example, the embodiments described above have been described in detail in order to explain the gist of the present invention in an easy-to-understand manner. Therefore, the present invention is not necessarily limited to having all the components described. Further, in the present invention, other components can be added to certain components, or some components can be changed to other components. Further, in the present invention, some components can also be deleted.

For example, the heating means of the deaerator 2 can be modified as shown in FIG. FIG. 7 is a diagram showing a modification of the heating means of the deaerator 2. In FIG.

In the example shown in FIG. 7, the deaerator 2 is configured to have a heat transfer member 47 instead of the heater 46 as a heating means. The heat transfer member 47 is a member that transfers the heat of the outer shell 41a (housing) of the deaeration module 41 (deaeration section) to the connection path 44a. The outer shell 41a (housing) of the degassing module 41 is heated to a temperature higher than the melting point of the liquid component of the ink by a heater (not shown). The heat transfer member 47 transfers the heat of its outer shell 41a (housing) to the connection path 44a, thereby heating the connection path 44a to a temperature higher than the melting point of the liquid component of the ink (for example, a temperature of 60° C. or higher). . Thereby, the deaerator 2 can suppress the liquid component of the ink from sticking inside the connection path 44a.

Note that the outer shell 41a (housing) of the degassing module 41 preferably has a relatively high thermal conductivity so that it can be adequately heated by a heater (not shown). Moreover, it is preferable that the heat transfer member 47 has a thermal conductivity comparable to or higher than that of the outer shell 41a (housing) so that the heat of the outer shell 41a (housing) can be efficiently transferred to the connection path 44a. Further, it is preferable that the outer shell 41a (housing) and the heat transfer member 47 have relatively high strength in order to make them difficult to break. Further, it is preferable that the outer shell 41a (housing) and the heat transfer member 47 have relatively high corrosion resistance, formability, and weldability. An aluminum alloy (for example, A5052 alloy) is a material that satisfies these demands. Therefore, the outer shell 41a (housing) and the heat transfer member 47 are preferably made of an aluminum alloy (eg, A5052 alloy). A5052 alloy is an alloy in which magnesium is added to aluminum. The A5052 alloy is a material that exhibits approximately intermediate strength among various aluminum alloys, and is a material that has excellent corrosion resistance, formability, and weldability. The thermal conductivity of the A5052 alloy is 140 W/m·K. Note that the thermal conductivity of the material of the outer shell 41a (housing) and the heat transfer member 47 is preferably close to that of A5052 alloy (for example, a thermal conductivity of 100 W/m·K or more).

In this way, the deaerator 2 can also prevent the liquid component of the ink from sticking inside the connection path 44a by having the heat transfer member 47 instead of the heater 46 as a heating means. can.

1 Inkjet recording device 2 Deaerator 9 External device 10 Paper feed section 11 Paper feed tray 12 Medium supply section 20 Image recording section 21 Conveyance drum (conveyance section)
21a Transport surface 22 Delivery unit 23 Paper heating section 24 Ink head unit 24a Housing 25 Fixing section 26 Delivery section 27 Ink supply section 30 Paper ejection section 31 Paper ejection tray 41 Deaeration module (deaeration section)
41a Outer shell (housing)
41b Center tube 41c Plug 41d Small hole (perforation hole)
41e Degassing membrane (hollow fiber membrane)
41f Silicon cap 41g Silicon cap 42 Trap 44 Vacuum path 44a Connection path 44b Communication path 45 Atmospheric path 46 Heater (heating means)
47 Heat transfer member (heating means)
51 Vacuum pump 60 Control unit 61 CPU
62 RAM
63 ROM
64 Storage section 71 Ink discharge head control section 72 Head unit movement drive section 73 Conveyance drive section 74 Input/output interface 221 Swing arm section 222 Delivery drum 240 Ink discharge head 240a Inlet 240b Outlet 240c Ink heating section 241 First sub tank 242 Ink flow path 242a First channel 242b Second channel 242c Third channel 242d Fourth channel 242e Fifth channel 243 Circulation pump 244 Check valve 245 Second sub tank 246 Valve 261 Delivery drum 262 Belt loop 271 Main tank 272 Supply pump 451 Atmospheric communication valve SP1, SP2, SP3 Space P Recording medium

Claims (12)

A degassing device used in an inkjet recording device,
a degassing section that desorbs gas from the ink flowing through the ink flow path;
a vacuum path through which the gas desorbed in the degassing section flows;
a trap provided on the vacuum path and storing a liquid component of the ink mixed in the gas;
A heating means for heating a connection path connecting the degassing section and the trap among the vacuum paths ,
The heating means is a heat transfer member that transfers heat from the degassing section to the connection path,
The thermal conductivity of the heat transfer member is 100 W/m·K or more.
A degassing device characterized by: A degassing device used in an inkjet recording device,
a degassing section that desorbs gas from the ink flowing through the ink flow path;
a vacuum path through which the gas desorbed in the degassing section flows;
a trap provided on the vacuum path and storing a liquid component of the ink mixed in the gas;
A heating means for heating a connection path connecting the degassing section and the trap among the vacuum paths,
The liquid component of the ink is sucked from the degassing section by a vacuum pump connected to the vacuum path while the atmospheric path connecting the inside of the degassing section and the outside at atmospheric pressure is open to the atmosphere. is collected in the trap by
A degassing device characterized by: 3. The degassing device according to claim 1, wherein the heating means heats the connection path to a temperature equal to or higher than the melting point of the liquid component of the ink. The deaerator according to claim 2 , wherein the heating means is a heater. The deaerator according to claim 1 , wherein the housing of the deaerator has a thermal conductivity of 100 W/m·K or more. 6. The degassing device according to claim 1 , wherein the ink has a viscosity of 7 centipoise or more when ejected from an ink ejection head that ejects the ink. The degassing section has a tubular hollow fiber membrane, and while degassing the ink with the hollow fiber membrane, fills the outside of the hollow fiber membrane with the degassed ink. The deaerator according to any one of claims 1 to 6 . The deaerator according to any one of claims 1 to 7 , wherein the connection path is connected to an upper part of the trap. The deaerator according to any one of claims 1 to 8 , wherein the trap is arranged near the deaerator. A degassing method used in an inkjet recording device, the method comprising:
The connection path connecting the degassing part that desorbs gas from the ink and the trap that stores the liquid component of the ink mixed in the gas is connected to the degassing part with a heat transfer member having a thermal conductivity of 100 W/m·K or more. A deaeration method characterized by heating the connection path by transmitting heat thereto . A degassing method used in an inkjet recording device, the method comprising:
heating a connection path connecting a degassing unit that desorbs gas from the ink and a trap that stores the liquid component of the ink mixed in the gas;
The liquid component of the ink is stored in a vacuum connected to a vacuum path through which the gas desorbed in the degassing section flows while the atmospheric path connecting the inside of the degassing section and the outside at atmospheric pressure is open to the atmosphere. It is collected into the trap by being sucked from the degassing section by a pump.
A deaeration method characterized by: A deaerator according to any one of claims 1 to 9 ,
an ink ejection head to which ink degassed by the deaerator is supplied;
An inkjet recording apparatus characterized in that an image is formed on a recording medium by discharging the ink from a nozzle provided in the inkjet head.

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