CN100436142C - Liquid ejecting apparatus - Google Patents

Abstract

A liquid ejection apparatus includes: an ejection head (210) having a nozzle plate (260) including openings (262), for ejecting liquid to a recording article (300); an absorbing member (420) disposed further than the recording medium (300) on the orbit of the liquid ejected from the nozzle plate (260), for absorbing the liquid which has not applied on the recording medium (300); an waste liquid absorbing member (600) having capillarity higher than that of the absorbing member (420) and being in contact with the absorbing member (420) on the connecting surface which is different from the absorbing surface, for sucking on the liquid which has been absorbed in the absorbing member (420); and a potential difference generating means (700) for generating a potential difference between the absorbing surface and the connecting surface of the absorbing member (420) and attracting the solute of the liquid from the absorbing surface to the connecting surface through electrophoresis. Thereby a nonvolatile solute is prevented from accumulating around the surface of the absorbing member.

Description

liquid injection device

Cross References to Related Applications

This application claims JP2005-044239 filed on February 21, 2005, JP2005-046269 filed on February 22, 2005, JP2006-009143 filed on January 17, 2006, and JP2006-009144 filed on January 17, 2006 Priority of Japanese Patent Application for , the contents of which are incorporated herein by reference.

technical field

The present invention relates to a liquid ejecting device, and more particularly, to a liquid ejecting device for applying a liquid ejected from nozzle openings of a nozzle plate mounted on a liquid ejecting head.

Background technique

Conventionally, when a liquid is applied over the entire margin of a recording medium such as paper, the liquid is ejected over an area larger than the size of the recording medium because the recording medium and the liquid ejection head can move. Therefore, the liquid is also ejected to areas surrounding both sides, upper and lower sides of the recording medium where the recording medium is not provided. If the liquid that is not applied to the recording medium is left, the liquid ejection device itself, unnecessary areas of the recording medium, and the user's hands may become soiled.

In addition, each small liquid droplet ejected from the liquid ejecting device is actively as small as several pl or pico-litres in order to improve recording resolution. Due to the extremely small mass of such droplets, the kinetic energy is quickly lost due to the viscous resistance of the environment as soon as they are ejected in the air. For example, a small droplet with an equivalent weight of less than 8 pl travels about 3 mm in air, and the velocity becomes almost zero. Meanwhile, the distance obtained by adding the space between the recording medium and the absorbing material to the gap between the nozzle plate and the recording medium is about 3-5 mm. Therefore, a portion of the droplets that are not applied to the recording medium loses kinetic energy before reaching the absorbing material. For small droplets without kinetic energy, the falling motion due to the acceleration of gravity and the viscous resistance of the environment is approximately proportional, so it takes a long time to complete the falling of small droplets.

Here, if the ejection speed is increased to extend the transfer distance of the small liquid droplet, the viscous resistance in the air acting on the small liquid droplet is further increased, so that the transfer distance is shortened despite its intention. Furthermore, if the ejection speed is increased, disadvantageously, conspicuously minute liquid droplets called satellite inks generated when the small liquid droplets are released from the nozzle plate are easily generated.

Furthermore, an operation called flushing is periodically performed in the liquid ejection device. Flushing is an operation in which the liquid ejection head is operated without any recording medium and the liquid is ejected. Thereby, liquids with increased viscosity in nozzles that are not used frequently are removed. However, the liquid ejected in flushing is only consumed for flushing and does not contribute to recording the recording medium. Accordingly, small or fine droplets are ejected to reduce liquid consumption. In addition, the throughput of the recording operation is reduced due to the time required for flushing, when flushing is performed, liquid is ejected from all the nozzles in a shorter time. In such a flushing operation, a large amount of satellite ink is produced.

Most of the satellite inks produced under the above-mentioned different conditions float around the area where the liquid ejection head is moved and become aerosols. A portion of the aerosol floats out of the liquid ejection device and is deposited around the liquid ejection device. Most of the aerosol then deposits on various parts in the liquid ejection device. Here, when aerosols are deposited on a transport path of a recording medium, such as a drum, the transported recording medium is often contaminated. In addition, when aerosols are deposited on the electrical circuits, linear scale, or various optical sensors of the liquid ejection device, it can lead to failure of the device itself. Furthermore, when the user touches the portion on which the aerosol is deposited, the user's hands become contaminated. Thus, a technique for collecting liquid not applied to a recording medium has been proposed, for example, as disclosed in Japanese Patent Application Publication No. 11-320891.

Here, a mechanism is proposed for guiding the liquid transferred to and reaching the drum without being applied to the recording medium into a waste liquid container different from the drum in the liquid ejecting device. In the liquid ejecting device, a through hole is provided in the drum, and the liquid in the drum is guided to a separate waste liquid container through the through hole. Thus, large amounts of liquid are prevented from remaining in the drum, as well as any airborne droplets or mist due to the collision of the droplets with each other.

However, since the amount of liquid applied to the drum is not constant, it unexpectedly takes time to release the liquid out of the drum, so that the liquid sometimes remains on the drum. In this case, it is impossible to prevent the generation of fog. Furthermore, if the release of liquid on the drum is delayed, the liquid medium evaporates and the non-volatile components remain on the drum. When nonvolatile components accumulate on the drum, the recording medium in contact with the drum is contaminated, and irregularities in the surface of the fluid passage are generated on the drum. Therefore, the flow of waste liquid can be easily stopped.

In order to solve the above-mentioned problems, a liquid ejecting device including an absorbing device is proposed in Japanese Patent Application Publication No. 2004-202867. The liquid ejection device includes absorbent means formed of a porous material on the drum for receiving liquid which has been applied to the recording medium and absorbing said liquid. The absorbent material itself has a suction ability due to capillary action, so that the received liquid is held therein without being spilled to the outside.

Furthermore, another liquid ejection device is proposed in Japanese Patent Application Publication No. 2004-202867. In the liquid ejection device, a metal member which will be an electrode is provided on the surface of the absorber, and an electric field is formed between a metal nozzle plate for ejecting liquid and the electrode. Since the small droplets ejected from the nozzle plate are filled with the same pole as the nozzle plate, the small droplets are transported towards the electrode without being reduced in speed by the Coulomb force acting between the electric field and itself, and then absorbed on the electrodes. The small droplets absorbed on the electrodes are finally absorbed in the absorbing member.

As described above, an absorbing member formed of a porous material is used in a liquid ejecting device to absorb liquid reaching a drum without being applied to a recording medium. Here, since the absorbent material using the porous material has a function of holding liquid due to its own capillary action, a certain amount of liquid is continuously held therein. However, the volatile components of the retained liquid evaporate around the surface of the absorbent member such that the non-volatile components collect concentratedly adjacent to the surface of the absorbent member. As a result, the absorbent member becomes clogged, so that the required function of the absorbent member to hold liquid without generating any mist may be lost. Additionally, most of the non-volatile components that collect on the surface of the absorbent member include colorant compositions. Thus, the recording medium supplied next may be contaminated.

Contents of the invention

In order to solve the above-mentioned problems, a first embodiment of the present invention provides a liquid ejecting apparatus including: a liquid ejecting head having a nozzle plate including openings for ejecting a liquid onto a recording medium; A part, the absorbing part is arranged farther than the recording medium on the track of the liquid ejected from the nozzle plate and has an absorbing surface for absorbing the liquid not applied to the recording medium; a waste liquid absorbing part, the waste liquid The absorbing member has a capillary action higher than that of the absorbing member, and is in contact with the absorbing member on a connection surface different from the absorbing surface, and the waste liquid absorbing member is used for sucking the waste liquid that has been absorbed in the liquid in the absorbing member, the connection surface being the contact surface of the absorbing member and the waste liquid absorbing member; and a potential difference generating means for generating a potential difference between the absorbing surface and the connecting surface of the absorbing member and transferring the The solutes of the liquid of the absorbing surface are attracted to the connecting surface by electrophoresis. Thereby, solutes such as dyes and pigments dispersed with charge in the liquid can actively move toward the portion in contact with the waste liquid absorbing member in the interior of the absorbing member. Accordingly, solutes are not concentrated around the surface of the absorbent member, so that the performance of the absorbent member is not deteriorated.

In a liquid ejecting device according to still another embodiment of the present invention, one end of the potential difference generating means is connected to a connection surface side electrode adjacent to an absorbing member surrounding the connection surface for positioning the connection surface. Thereby, positioning and good electrical connection of the absorbing part can be achieved with a simple structure.

In a liquid ejecting device according to still another embodiment of the present invention, the other end of the potential difference generating means is connected to an absorbing surface side electrode disposed adjacent to the absorbing surface. Thereby, the potential of the surface of the absorbing member is clearly defined so that the solute can be efficiently sucked.

In a liquid ejecting device according to still another embodiment of the present invention, the other end of the potential difference generating means is connected to the absorbing surface side electrode provided adjacent to the rear surface of the absorbing surface. The electrodes at the other end are thus not wetted by the charged liquid, so that the electric field formed across the electrodes is prevented from deteriorating.

In a liquid ejecting device according to still another embodiment of the present invention, the other end of the potential difference generating means is connected to an absorbing surface side electrode embedded in the absorbing means. Thereby, the contact between the electrode at the other end and the absorbing member is properly maintained. In addition, mutual positioning can be obtained with each other, so that stable performance can be achieved.

Furthermore, according to the liquid ejection device of still another embodiment of the present invention, the liquid ejection device has an external potential difference generating means for generating a potential difference between the nozzle plate and an absorbing surface of an absorbing member other than the absorbing member, and for electrically connecting the Liquid sprayed from the nozzle plate is attracted to the absorbing surface. Thus, the electric field generated between the nozzle plate and the absorbent member other than the absorbent member causes the aerosol to be attracted to the absorbent member. The aerosol attracted to the absorbing member is absorbed in the absorbing member, and then, the solute contained in the liquid is attracted into the waste liquid absorbing member due to an electric field generated inside the absorbing member. Accordingly, aerosols floating inside are reduced, and non-volatile solutes are prevented from concentrating around the surface of the absorbent member.

Furthermore, in a liquid ejection device according to still another embodiment of the present invention, the nozzle plate has conductivity, and one end of the external potential difference generating means is connected to the nozzle plate. An electric field is thereby formed including one end of the nozzle plate, so that aerosols can be efficiently collected.

Furthermore, in a liquid ejecting device according to still another embodiment of the present invention, the other end of the external potential difference generating means is connected to its connection surface side electrode adjacent to the absorbing member around the connection surface for positioning the connection surface. Thereby the absorbing part can be positively positioned without increasing the number of parts. In addition, liquid can be smoothly absorbed from the absorbent member to the waste liquid absorbent member.

Furthermore, in a liquid ejecting device according to still another embodiment of the present invention, the other end of the external potential difference generating means is connected to the absorbing surface side electrode disposed adjacent to the absorbing surface. An electric field is thereby generated between the nozzle plate and the absorbing surface, which allows efficient collection of aerosols.

Furthermore, in a liquid ejecting device according to still another embodiment of the present invention, the other end of the external potential difference generating means is connected to the absorbing surface side electrode provided adjacent to the rear surface of the absorbing surface. Thereby, any liquid is not directly applied to the absorbing surface side electrode, so that desired properties can be maintained for a longer period of time.

Furthermore, in a liquid ejection device according to still another embodiment of the present invention, the potential difference generating means and the external potential difference generating means include separate potential difference generating circuits, respectively. Thereby, the potential of the surface of the absorbing member is properly set, so that the required electric field can be easily generated.

Furthermore, in a liquid ejection device according to still another embodiment of the present invention, the potential difference generating means and the external potential difference generating means include a single potential difference generating circuit, and a switching circuit for selectively switching the potential difference generating circuit among them. A first connection state in which the output is coupled to the absorption surface and the connection surface of the absorption part and a second connection state in which the output of the potential difference generating means is coupled to the nozzle plate and the absorption part. Thus, one potential difference generating device is switchably used in the liquid ejecting device, so that the number of parts can be reduced, the cost can be reduced, and the device can be more compact.

Here, the technical term "solute" described in the specification is all components other than the medium mainly contained in the liquid used for the liquid ejection device. Furthermore, solutes include liquid substances dissolved in a medium as well as substances dispersed in a medium in solid condition.

Here, not all essential features of the invention are listed in the summary of the invention. Subcombinations of the described features may become the invention.

Description of drawings

FIG. 1 is a perspective view of an entire ink jet recording device 11 of one type of liquid jetting device.

FIG. 2 is a perspective view of the internal mechanism 12 of the inkjet recording device 11 .

FIG. 3 is a schematic diagram of the collection mechanism 13 that may be implemented in the inkjet recording device 11. As shown in FIG.

FIG. 4 is a schematic diagram of an additional collection mechanism 13 that may be implemented in the inkjet recording device 11 .

FIG. 5 is a schematic diagram of an additional collection mechanism 13 that may be implemented in the inkjet recording device 11 .

FIG. 6 is a schematic diagram of an additional collection mechanism 13 that may be implemented in the inkjet recording device 11 .

FIG. 7 is a schematic diagram of an additional collection mechanism 13 that may be implemented in the inkjet recording device 11 .

Figure 8 is a graph of the relationship between the applied electric field and the number of aerosols in an embodiment.

FIG. 9 is a logarithmic view of the number of aerosols in the view shown in FIG. 8 .

FIG. 10 is a schematic diagram of an additional collection mechanism 13 that may be implemented in the inkjet recording device 11 .

FIG. 11 is a schematic diagram of an additional collection mechanism 13 that may be implemented in the inkjet recording device 11 .

Detailed ways

Hereinafter, the invention will be described with reference to the cited examples. The embodiments are not limited to the invention according to the claims, and all combinations of features described in the embodiments are not necessarily essential to the means for solving the problems of the invention.

FIG. 1 is a perspective view of an entire inkjet recording device 11 that is one example of a liquid ejecting device. As shown in FIG. 1 , an inkjet recording device 11 includes a lower case 20 serving as a main part of the device, an upper case 22 for forming a case in cooperation with the lower case 20 , connected to the lower case 20 The paper supporter 10 on the back side and the release tray 30 are formed in front of the lower case 20 . Here, as shown in FIG. 1 , when the upper case 22 serving as a cover is opened, a platen 400 horizontally provided in the lower case 20 and a carriage 200 provided above the platen 400 appear. .

In the inkjet recording apparatus 11 described above, the recording media 300 loaded in the paper support 10 are fed onto the drum 400 one by one, and then these are fed to the discharge tray 30 through a discharge unit (not shown in the drawing). The carriage 200 reciprocates in a direction perpendicular to the transport direction of the recording medium 300 over the drum 400 . In this way, the transfer of the recording medium 300 and the reciprocation of the carriage 200 are sequentially performed such that the entire top surface of the recording medium 300 can be scanned by the carriage 200 . Therefore, an image may be recorded or printed on any area of the recording medium 300 .

FIG. 2 is a perspective view showing the internal mechanism 12 of the inkjet recording device 11. As shown in FIG. As shown in FIG. 2 , the internal mechanism 12 is surrounded by a frame 100 , a pair of side surface portions 110 , 111 . Here, the internal mechanism 12 is mainly formed in an area configured by a frame 100 disposed substantially vertically, and a pair of side surface portions 100 and 111 extending forward from both sides of the frame 100 in parallel to each other.

The carriage 200 is held by a guide shaft 220 penetrating the carriage 200 in the internal mechanism 12 . Both ends of the guide shaft 220 are supported by the side surface 110 and the side surface 111 , and the guide surface 220 is disposed parallel to the frame 100 . Accordingly, the carriage 200 may move horizontally along the guide shaft 220 .

Behind the carriage 200 , a pair of pulleys 242 and 244 , and a timing belt placed around the pulleys 242 and 244 are provided in front of the frame 100 . The pulley 244 is rotatably driven by a carriage motor 246 . A gear belt 230 is connected to the back side of the carriage 200 . Accordingly, the carriage 200 may reciprocate according to the operation of the carriage motor 246 .

Ink cartridge 250 is loaded into carriage 200 . The recording head 210 is disposed on the bottom surface of the carriage 200 . The recording head 210 includes a metal nozzle plate 260 having openings for ejecting ink droplets. Accordingly, ink droplets are ejected downwardly from the carriage 200 .

The carriage 200 is connected to the circuit 120 behind the frame 100 through a ribbon multi-core cable 270 . The multi-core cable 270 flexibly bends according to the movement of the carriage 200 so as not to avoid the reciprocation of the carriage 200 .

The drum 400 is disposed below the area where the carriage 200 passes. The roller 400 is supported from under the recording medium 300 passing under the carriage 200 and keeps the distance between the nozzle plate 260 and the recording medium 300 constant.

A concave portion 410 is formed on the top surface of the drum 400 . The absorbing member 420 is accommodated in the recess 410 . The absorbing member 420 receives ink ejected from the recording head 210 to an area where the recording medium 300 is not present.

Here, ink is gradually deposited on the absorbing material 420 as the operating time of the inkjet recording apparatus 11 elapses. If the recording medium 300 is in contact with the absorbing member 420 on which ink is applied, the recording medium 300 is contaminated with ink. In order to prevent such contact, a raised portion is formed on the top surface of the drum 400, and then the recording medium 300 is raised from below and held by the raised portion. Accordingly, a gap of about 3-5 mm is formed between the nozzle plate 260 and the absorption member 420 .

The absorbing capacity of the absorbing member 420 including the roller 400 is limited because its material is selected with emphasis on absorbing speed on the surface. Here, a larger waste liquid absorbing member 600 is disposed under the drum 400 and communicates with the absorbing member 420 . For the waste liquid absorbing member 600, its absorbing capacity is important, and further, a material with higher absorbency is selected by capillary action. Therefore, the waste liquid absorbing member 600 can absorb a larger amount of ink from the absorbing member 420 .

Meanwhile, the transfer roller 310 is disposed in the back side of the drum 400 . The transfer roller 310 is driven by a transfer motor 320 provided in the back side of the frame 100 . The transfer roller 310 cooperates with a compliance roller (not shown in the drawing) to feed the recording medium 300 onto the drum 400 . As described above, the carriage may reciprocate in a direction perpendicular to the direction in which the recording medium 300 may be transported. Therefore, conveyance of the recording medium 300 and reciprocation of the carriage 200 are performed in turn while the recording head 210, which is the bottom surface of the carriage 200, operates intermittently, so that ink can be ejected to any area on the recording medium and applied thereto. .

In the internal mechanism 12 , the cover member 500 is disposed in a side of the side surface 110 with respect to the drum 400 . The cover part 500 can move up and down. Then, the cover member 500 rises to seal the surface of the nozzle plate 260 when the carriage 200 stops at a home position close to the side surface 110. The inside of the cover member 500 is connected to the pump unit 510 . The pump unit 510 may suck ink applied to the surface of the nozzle plate 260 . The ink sucked in the pump unit 510 is absorbed in the waste liquid absorbing member 600 through a tube (not shown in the drawing).

In addition, a wiping device 520 is disposed between the drum 400 and the cover member 500 . The wiping device 520 wipes the bottom surface of the nozzle plate 260 to clean it when the carriage 200 released from the cover member 500 passes thereon.

3 is a drawing for explaining the embodiment, and the operation of the collecting mechanism 13 for forming an electric field inside the absorbing member 420 in the inkjet recording device 11 including the above-described internal mechanism 12 . As shown in FIG. 3, an absorbing member 420 is accommodated inside the drum 400 for supporting the recording medium 300 under the nozzle plate 260 having the opening 262 for ejecting ink. The top surface of the absorbing member 420 is formed as an absorbing surface facing the nozzle plate 260 . In addition, a part of the absorbing member 420 is inserted into a hole formed at the bottom of the drum 400 and extends downward. A region around the bottom end of the absorbent member 420 is formed as a connection surface that contacts the top surface of the waste liquid absorbent member 600 .

The absorption surface side electrode 430 is provided in the top surface of the absorption member 420 . The connection surface side electrode 440 is provided in the bottom end of the absorbing member 420 . Each of the absorbing surface side electrodes 430 and the connecting surface side electrodes 440 is provided in contact with the absorbing member 420, respectively. Here, the connection surface side electrode 440 is connected to one end of the potential difference generating device 700 to facilitate application of the potential difference, holds the bottom end of the absorbent member 420 and sets the bottom end to a position where the bottom end adjoins the waste liquid absorbent member 600 superior. Meanwhile, the other end of the potential difference generating device 700 is electrically connected to the absorbing surface side electrode 430 . Accordingly, a potential difference V depending on the output of the potential difference generating device 700 is formed between the absorption surface side electrode 430 and the connection surface side electrode 440 . The potential difference V causes an electric field E to be formed between the absorbing surface of the absorbing member 420 facing the nozzle plate 260 and the connection surface in contact with the waste liquid absorbing member 600 .

In the inkjet recording apparatus 100 including the collecting mechanism 13 formed as above, when any recording medium 300 is disposed directly under the opening 262 of the nozzle plate 260, the small liquid droplets 268 ejected from the nozzle plate 260 are applied to the recording medium 300 on. Here, when it is intended to apply the ink entirely to the edge of the recording medium 300 , both sides, top and bottom ends of the recording medium may not be disposed directly under the opening 262 . In this case, an ink column 264 ejected from the opening 262 becomes a small liquid droplet 266 . The small liquid droplets 266 are then contained and absorbed directly in the absorbent member 420 .

Solutes in liquids are ionized and have charges specific to their constituents. Here, a substance having a charge in a liquid moves a pole opposite to its own charge by electrophoresis by applying an electric field to the liquid. Therefore, when the electric field E is formed by the absorbing surface side electrode 430 and the connecting surface side electrode 440, it can be selected such that the pole of the charge of the solute in the ink is opposite to that of the connecting surface side electrode 440 so that the solute faces toward the connecting surface side Electrode 440 moves. In this way, the polarity of the potential difference V applied by the potential difference generating device 700 is appropriately selected according to the composition of the solute of the ink. Therefore, as indicated by the distribution of black spots in the absorbing member 420 as shown in FIG. 3 , solutes in the ink can move to the connection surface side electrode 440 by electrophoresis.

Effective electrophoresis in the absorbing member 420 is expressed under the condition that a sufficient amount of ink is absorbed in the absorbing member 420, and the absorbing surface side electrode 430 and the connecting surface side electrode 440 are coupled through the solvent of the ink. Meanwhile, only a small amount of ink is contained in the absorbing member 420 at the start of the operation of the inkjet recording apparatus 11 . Therefore, arbitrary efficient electrophoresis can be generated. Then, when the recording operation continues, and the absorbing member 420 accommodates a certain amount of ink, the solvent continuously exists in the absorbing member for about several tens of seconds. Therefore, the solute moves into the absorbing member 420 by electrophoresis, so that the solute is prevented from being concentratedly collected on the surface of the absorbing member 420 . In addition, when the amount of ink contained in the absorbing member 420 is further increased, and the solvent extends to the connection surface side electrode 440, the solutes moved by the electrophoretic effect are sequentially absorbed in the waste liquid absorbing member 600. Therefore, no solute remains in the absorbent member 420, which prevents the performance of the absorbent member 420 from being reduced due to the accumulation of solutes.

Preferably, the above-mentioned solute collection is performed immediately after the recording operation of the inkjet recording device 11 ends, so that a good effect is achieved. Therefore, preferably, a timer (not shown in the figure) for controlling the potential difference generating device 700 of the collecting mechanism 13 is provided, and the collecting mechanism 13 starts from several minutes to one hour after the recording operation of the inkjet recording device 11 ends. operate continuously during a specified period of hours. Thus, the solutes of the ink are removed from the absorbing member 420 immediately after the end of the recording operation of the inkjet recording apparatus 11, so that any solute components are not accumulated in the absorbing member 420 even if the recording operation is not performed for a long time after ending the foregoing operation. time.

Thus, the solute is moved to the connection surface side electrode 440, so that the solute adjacent to the absorbing member 420 is reduced. Therefore, solutes of non-volatile components do not accumulate on the surface of the absorbing member 420 even if volatile components in the ink evaporate. In addition, in the bottom end of the absorbing member 420, the solute is absorbed together with the medium by the waste liquid absorbing member 600 having a stronger absorbing capacity. Therefore, solutes do not collect in the bottom end of the absorbent member 420 either. Here, pulp and compressed chemical fibers, or materials obtained by mixing polymer absorbents may be preferably used as the waste liquid absorbing member 600 .

FIG. 4 is a view for explaining another embodiment and explaining the operation of the collection mechanism 13 . In FIG. 4 , each component equivalent to that of the other drawings is identified with the same reference numeral, and redundant explanations are omitted. As shown in FIG. 4 , one end of the potential difference generating device 700 is connected to the connection surface side electrode 440 in the collection mechanism 13 as well as in FIG. 3 . Meanwhile, the absorbing surface side electrode 431 connected to the other end of the potential difference generating device 700 is embedded in the recess 410 of the drum 400 , that is, the absorbing surface side electrode 431 is embedded in its own absorbing member 420 . This is a feature of the structure according to this embodiment.

In this embodiment, referring to FIG. 3 , other structures are the same as those of the above embodiment. According to such a structure, an electric field E is generated between the top surface and the bottom end of substantially the absorbing member 420 due to the potential difference V output by the potential difference generating device 700 . Therefore, the solute of the ink absorbed in the absorbing member 420 can move to the connection surface side electrode 440, so that the solute adjacent to the absorbing member 420 can be reduced.

FIG. 5 is a view explaining another embodiment and the operation of the collecting mechanism 13 . In FIG. 5 , each equivalent component to that in the other views is identified with the same reference numeral, and duplicate descriptions are omitted. As shown in FIG. 5 , one end of the potential difference generating device 700 is connected to the collection structure 13 and the connection surface side electrode 440 in FIG. 4 . Meanwhile, the absorbing surface side electrode 432 connected to the other end of the potential difference generating device 700 is formed by a conductor provided on the bottom of the recess 410 of the drum 400 . That is, the absorbing surface side electrode 432 is disposed on the rear surface facing the plane of the nozzle plate 260 of the absorbing member 420 .

Here, the absorbing surface side electrode 432 covers substantially the entirety of the bottom of the concave portion of the drum 400, and the absorbing member 420 having the same shape as the absorbing surface side electrode 432 is housed thereon. Thus, the entire bottom surface of the absorbing member 420 is in contact with the absorbing surface side electrode 432, so that the absorbing member 420 and the absorbing surface side electrode 432 are electrically connected over a larger area. Therefore, even if there is any part not electrically connected to the structure of the absorbing member 420 , the potential of the entire absorbing member 420 is substantially the same as that of the absorbing surface side electrode 432 . Meanwhile, in a part of the absorbing member 420 , the resistance effect increases in proportion to the distance from the absorbing surface side electrode 432 . Accordingly, an electric field E based on the potential difference V is formed in a portion extending below the absorption member 420 .

As described above, a unique electric field E is formed in this embodiment. However, a potential difference is generated between the surface of the absorbing member 420 and the bottom end of the absorbing member 420, and an electric field E is formed therebetween as in the foregoing embodiments. Therefore, the solute in the ink absorbed in the absorbing member 420 can move to the connection surface side electrode 440, so that the solute adjacent to the absorbing member 420 can be reduced.

Here, in the embodiment described with reference to FIGS. 3 , 4 and 5, a metal having corrosion resistance with respect to the ink used for the inkjet recording device 11, such as gold, stainless steel, or nickel, or formed by electroplating these with copper The obtained material can be used as a material for, for example, the respective absorbing surface side electrodes 430 , 431 , 432 and 440 . In addition, a member formed by arranging approximately 0.1 mm to 0.5 mm of linear materials or plates formed of the above-mentioned materials in parallel at intervals of 0.5 mm to 4 mm, or combining them in a mesh pattern can be used for each Components of the surface-side electrodes 430 , 431 , 432 and 440 are absorbed. Furthermore, preferably, the member serving as the absorbing-side surface-side electrodes 430 , 431 includes a passage area having a size sufficient to pass incoming ink to the bottom of the absorbing member 420 . In addition, foamed resins such as polyethylene and polyurethane may be used as the absorbent member 420, for example, but this is not limited to those materials either.

FIG. 6 is a schematic diagram showing the structure and function of the collection mechanism 13 that can collect aerosols floating around the nozzle plate 260 and solutes in the absorbing member 420 in the inkjet recording device 11 . Here, each component equivalent to that of other drawings is identified with the same reference numeral, and repeated description thereof is omitted in FIG. 6 .

As shown in FIG. 6 , the absorbing member 420 is accommodated in a recess portion 410 in the drum 400 of the collection mechanism 13 . The top surface of the absorbing member 420 is an absorbing surface for containing ink. In addition, a portion of the absorbing member 420 is inserted into a hole formed in the bottom of the drum 400 and extends downward, and a part around the downwardly extending portion contacts the top surface of the waste liquid absorbing member 600 as a connection surface.

In addition, the connection surface side electrode 440 is connected to the bottom end of the absorption member 420 . The connection surface side electrode 440 is connected to the other end of the potential difference generating device 700 to facilitate application of the potential difference, and has a physical function for holding and positioning the bottom end of the absorbing member 420 .

Here, a metal having corrosion resistance with respect to the ink used in the inkjet recording device 11, such as gold, stainless steel, or nickel, or a material obtained by electroplating copper on these metals can be used as a material for, for example, the connection surface side electrode 440 .

As for the material for the absorbing member 420, a conductive material having a surface resistance of less than 10 ⁸ Ω can be used such as by mixing such as polyethylene and polyurethane with such as metal and carbon and foaming the mixture. A material obtained, and a material obtained by applying a conductive material such as metal and carbon to a foam material such as polyethylene and polyurethane, or plating a foamed resin with a conductive material. In addition, a material obtained by impregnating a foamed resin such as polyethylene and polyurethane into an electrolytic solution may be used as the absorbent material 420 .

In the collecting mechanism 13 for collecting satellite ink and solution as shown in FIG. 6 , a plurality of openings 262 for ejecting ink are formed in the nozzle plate 260 . Typically, the recording medium 300 supported by the roller 400 from below is placed immediately under the nozzle plate 260 . Accordingly, small liquid droplets 268 ejected from the nozzle plate 260 are applied onto the recording medium 300 .

Meanwhile, when it is intended to apply ink to the entire edge of the recording medium 300 , both sides, top and bottom ends of the recording medium may not be disposed directly under a part of the opening 262 . In this case, the kinetic energy applied to the liquid 266 sprayed through the opening 262 is rapidly lost due to viscous resistance, and the kinetic energy of a part of the small liquid droplet 266 is completely lost long before reaching the absorbing member 420 . Furthermore, since the droplet 266 has a very small mass, the downward motion due to the acceleration of gravity is approximately equal to the viscous drag due to the atmosphere, so that the falling speed of the droplet 266 is significantly slower. In this way, aerosols are generated and float below the nozzle plate 260 .

Here, in the collection mechanism 13 as shown in FIG. 6, the electric field E1 is formed between the nozzle plate 260 and the absorbing member 420, and the electric field E2 is formed on the top surface of the absorbing member 240 which is the absorbing surface and is the connecting surface, respectively. between the bottom ends of the absorbent member 420 of the surface. That is, one end of the potential difference generating means 700 is connected to the nozzle plate 260, and the other end thereof is connected to the connection surface side electrodes 440, respectively, so that a potential difference V is generated therebetween. In addition, a potential difference is generated between the connection surface and the absorbing surface of the absorbing member 420 due to a voltage drop according to the DC resistance value of the absorbing member 420 . Accordingly, an electric field E1 is generated between the nozzle plate 260 and the absorbing surface of the absorbing member 420 according to the potential difference and the distance therebetween. In addition, an electric field E2 is also generated between the absorbing surface and the connecting surface of the absorbing member 420 according to the potential difference and the distance therebetween.

The ink ejected from the opening 262 becomes an ink column 264 that will fall from the nozzle plate 260 immediately before it becomes a small droplet 266 . At this time, it produces a so-called light-emitting conductor effect between the tip A of the ink column 264 and the region B of the bottom surface of the nozzle plate 260 surrounding the ink column 264 . In other words, the light-emitting conductor effect is that the area B on the surface of the nozzle plate 260 surrounded by a cone with an apex angle of 50° to 60° helps to charge the small droplet 266, and the apex is the tip A of the ink column 260 (as shown in FIG. shown in the middle bottom). The charge of the small droplet 266 is greater than that of the horizontal cross-section of the ink column 264 due to the light conductor effect.

Next, ink column 264 exits nozzle plate 260 and becomes a small droplet 266 . Then, the small liquid droplet 266 has a charge q accumulated due to the light-emitting conductor effect described above. Therefore, the small liquid droplet 266 having the electric charge q acquires kinetic energy by the Coulomb force (qE1) from the electric field E1, moves downward without deceleration, and can reach the absorbing member 420.

In addition, an electric field E2 is formed within the absorbing member 420 . A solute in a liquid has a charge that is unique to each component. Components with charge generate electrophoresis to move toward the pole opposite to the pole of charge in the electric field. Therefore, if it is selected such that the polarity of the connection surface side electrode 440 is opposite to the charge of the solute of the ink contained in the absorbing member 420 , the solute can be attracted to the connection surface side electrode 440 . In this way, the solutes in the ink can move to the connection surface side electrode 440 shown in the distribution of black dots in the absorbing member 420 of FIG. 6 as shown in the figure.

Here, effective electrophoresis within the absorbing member 420 is expressed under the condition that a sufficient amount of ink is absorbed in the absorbing member 420, and the electrodes for forming the electric field E2 are coupled through the solvent of the ink. Meanwhile, only a small amount of ink is contained in the absorbing member 420 when the inkjet recording apparatus 11 is started to operate. Therefore, sometimes no effective electrophoresis occurs at the beginning of operating the inkjet recording apparatus 11 . Then, the recording operation is continued, and the absorbing member 420 gradually accommodates a certain amount of ink so that the solvent is continuously accommodated in the absorbing member 420 . Therefore, the solute moves into the absorbing member 420 by electrophoresis, so that it prevents the solute from concentrating on the surface of the absorbing member 420 . In addition, solutes reaching the waste liquid absorbing member 600 are sequentially absorbed from the absorbing member 420 . Accordingly, any solutes are not retained in the absorbent member 420, so that the performance of the absorbent member 420 is prevented from being reduced due to accumulation of solutes.

To move the solute toward the connection surface side electrode 440 within the absorption member 420 whose capacity is limited means that the solute adjacent to the absorption surface of the absorption member 420 is reduced. Accordingly, even if volatile components evaporate from the absorbing surface of the absorbing member 420, solutes that are non-volatile components of the ink do not accumulate adjacent to the absorbing surface. In addition, the solute is absorbed together with the medium in the connection surface of the absorbing member 420 by the waste liquid absorbing member 600 having a stronger adsorption capacity. Therefore, no solutes accumulate on the bottom end of the absorbent member 420 . Here, pulp, compressed chemical fibers, or a material obtained by mixing polymer absorbents may be preferable as the material for the waste liquid absorbing member 600 .

Figure 7 shows a schematic diagram of an additional embodiment of a collection mechanism 13 for collecting satellite ink and solutes. Here, the same components as in FIG. 6 are also identified by the same reference numerals, and repeated descriptions are omitted. As shown in FIG. 7 , a meshed absorption-side electrode 430 is provided on the top surface of the absorption member 420 . The unique feature of this embodiment is that a pair of potential difference generating means are separately provided. Here, one of the external potential difference generating means 710 for generating the potential difference V ₁ is provided between the nozzle plate 260 and the absorbing surface side electrode 430 . A further internal potential difference generating device 720 for generating a potential difference V ₂ is arranged between the absorbing surface and the connecting surface of the absorbing part 420 . Here, “inside” means that the internal potential difference generating device 720 is a potential difference generating device for forming the electric field E ₂ inside the absorbing member 420 .

Due to the above structure, the electric field _E1 between the nozzle plate 260 and the absorbing surface side electrode 430, and the electric field _E2 between the absorbing surface side electrode 430 and the connecting surface side electrode 440 can be appropriately set respectively. Accordingly, aerosols can be efficiently absorbed in the absorbent member 420, and solute liquids in the absorbent member 420 can be efficiently moved to the connection surfaces, respectively.

Here, as a material for the absorbing surface side electrode 430, a metal having corrosion resistance with respect to the ink used for the inkjet recording device 11, such as gold (aurum), stainless steel (stainless), or nickel, or by plating these Materials obtained from copper can be used. In addition, a member formed by arranging approximately 0.1 mm to 0.5 mm linear materials or plates formed of the above materials in parallel at intervals of 0.5 mm to 4 mm, or combining them in a mesh pattern can be used as a material for absorbing Components of the surface-side electrode 430 . In addition, it is preferable that a member serving as the absorbing surface side electrode 430 includes a passage area having a size sufficient to pass incoming ink to the bottom of the absorbing member 420 . In addition, foam materials such as polyethylene and polyurethane may be used as the material of the absorbent member 420, for example, but this is not limited to those materials either.

Preferably, the solute collecting operation is performed immediately after the recording operation of the inkjet recording device 11 is completed, which achieves a good effect. Therefore, preferably, after the recording operation of the inkjet recording device 11 is completed, a timer (not shown) for controlling the internal potential difference generating device 720 connected to the collecting mechanism 13 is provided to continuously operate the collecting mechanism 13 A specific period from a few minutes to an hour. Therefore, the solute of the ink is removed from the absorbing member 420 immediately after the recording operation of the inkjet recording apparatus 11 is completed, so that any solute components are not accumulated in the absorbing member even when the recording operation is not performed for a long time after the aforementioned operation is completed. 420 in.

FIG. 8 shows a graph of the relationship between the applied electric field and the number of aerosols in the embodiment shown in FIG. 7 . That is, when the output of the internal potential difference generating means 720 is kept in a constant state, electric fields having different intensities are generated between the nozzle plate 260 and the absorbing surface side electrode 430 and recorded. The resulting amount of aerosol is then measured and plotted. When the measurement was performed, the average size of the small liquid droplets was determined to be 7p1, and the 5-layer recording medium having the A4 size was recorded for 7 minutes and 38 seconds after the start of printing. In addition, the total number of aerosols recorded 8 minutes after the start of printing was divided by 8 and the resulting value was the number of aerosols per minute. As shown in Figure 8, when the electric field is greater than 25 Kv/m, the number of aerosols is significantly reduced compared to no electric field. Therefore, it can be understood that the aerosol can be collected to a satisfactory degree.

FIG. 9 is a logarithmic graph showing the relationship between the number of aerosols (vertical axis) and the applied electric field (horizontal axis) as shown in FIG. 8 . As shown in Figure 9, when the applied electric field was set at a higher level, the number of aerosols decreased continuously, and then, the rate of decrease gradually slowed down. Furthermore, when the applied electric field is greater than 250 KV/m, the rate of decrease is not uniform. Therefore, it can be understood that the utilization rate of the applied electric power decreases.

FIG. 10 is a schematic diagram showing a modification of the embodiment shown in FIG. 7 . As shown in FIG. 10 , the collection mechanism 13 includes a single potential difference generating device 700 and a switching device 800 for switching the destination of the potential difference generating device 700 under the control of a switching signal. That is, the switching device 800 can optionally apply the potential difference generated by the potential difference generating device 700 between the nozzle plate 260 and the absorption surface side electrode 430 and between the absorption surface side electrode 430 and the connection surface side electrode 440. V. For the period when the recording head 210 is operating and the ink is ejected from the nozzle plate 260 and the period immediately after, the switching device 800 is moved to the first state by the switching signal so that the potential difference V is between the nozzle plate 260 and the absorption surface side electrode 430 produce. At this time, the aerosol is attracted to the absorbing member 420 due to the electric field E ₁ generated between the nozzle plate 260 and the absorbing surface side electrode 430 .

Next, when the ejection of ink is completed, the switching means 800 is moved to the second state by the switching signal, so that a potential difference V is generated between the absorption surface side electrode 430 and the connection surface side electrode 440 . At this time, since the electric field _E2 is generated between the absorbing surface side electrode 430 and the connecting surface side electrode 440, the solute contained in the ink moves to the connecting surface in the absorbing member 420, so that the solute is reduced on the absorbing surface.

As described above, the aerosol collecting operation and the aerosol moving operation are switchably performed by a single potential difference generating device 700 . Therefore, the number of potential difference generating devices is reduced, so that the cost can be reduced, and the electric power for operating the inkjet recording device 11 can be saved.

FIG. 11 is a schematic diagram showing a modification of the collection mechanism 13 shown in FIG. 10 for collecting satellite ink and solute. Here, the same components as those in other views are marked with the same reference numerals, and repeated explanations are omitted.

As shown in FIG. 11, according to the absorbing surface side electrode 431 formed with the conductive plate provided on the bottom of the recess 410 in the drum 400 adjacent to the absorbing member 420 in the drum 400 is the collecting mechanism 13 according to the present embodiment. unique features. In other words, in the present embodiment, the absorbing surface side electrode 431 is provided on the rear surface facing the plane of the nozzle plate 260 of the absorbing member 420 . Here, preferably, the material used for the absorbing member 420 has conductivity. Other structures are the same as the embodiment shown in FIG. 10 .

The absorbing surface side electrode 431 covers substantially the entire bottom of the recess 410 of the drum 400, and the absorbing member 420 having substantially the same shape as the absorbing surface side electrode 431 is accommodated thereon in this embodiment. Thus, the entire bottom surface of the absorbing member 420 is in contact with the absorbing surface side electrode 431, so that the absorbing member 420 and the absorbing surface side electrode 431 are electrically connected over a larger area. Therefore, even if there is any portion not electrically connected in the structure of the absorbing member 420 , the potential of the entire absorbing member 420 is substantially the same as that of the absorbing surface side electrode 431 . In addition, since the absorbing surface side electrode 431 is disposed on the rear surface of the absorbing member 420, any ink is not directly applied to the absorbing surface side electrode 431, so that desired performance can be maintained for a longer period of time.

Here, as a material for the absorption-side electrode 431 , a metal having corrosion resistance with respect to the ink used for the inkjet recording device 11 , such as gold, stainless steel, or nickel may be used. In addition, electrode parts by plate materials formed with these raw materials can be used. In addition, a linear material obtained by combining these materials, or a sheet material or a perforated or latticed member may be used. In addition, a conductive coating, a plating layer, a thick film layer, and a thin film layer directly formed in the concave portion 410 of the drum 400 may be used.

For the period in which the recording head 210 operates and the ink is ejected from the nozzle plate 260 and the period immediately thereafter, the switching mechanism moves to the first state, so that in this embodiment as well as in the preceding embodiments, the potential difference V between the nozzle plate 260 and the Absorption occurs between the surface side electrodes 430 . At this time, the aerosol is attracted to the absorbing member 420 due to the electric field E ₁ generated between the nozzle plate 260 and the absorbing surface side electrode 430 .

Next, when the ejection of the ink is completed, the switching means 800 moves to the second state, so that a potential difference V is generated between the absorption surface side electrode 430 and the connection surface side electrode 440 . At this time, since the electric field _E2 is generated between the absorbing surface side electrode 430 and the connecting surface side electrode 440, the solute contained in the ink moves to the connecting surface in the absorbing member 420, so that the solute is reduced on the absorbing surface.

As described above in detail, the inkjet recording device 11 has a function for moving the solute contained in its absorbing member 420 to the waste liquid absorbing member 600 by electrophoresis. Therefore, solutes are not collected on the surface of the absorbing member 420, and useless ink for recording on the recording medium 300 can be stably collected and set.

Here, a color jetting device for manufacturing a filter of a liquid crystal display, an electrode forming device for manufacturing an organic EL display and an FED (Field Emission Display), or a sample jetting head for manufacturing a biochip are used as an operation example, The operation examples can be used as embodiments of the present invention, but are not limited to them.

Although the present invention has been described with reference to the embodiments, the technical scope of the present invention is not limited to the above-described embodiments. It is obvious that various changes and modifications can be added to the above-described embodiments by those skilled in the art. It is apparent from the scope of the claims that such modifications or improvements may be included in the technical scope of the present invention.

Claims (12)

1. liquid injection apparatus comprises:

Jet head liquid, described jet head liquid has the nozzle plate that comprises opening, is used to inject liquid into recording medium;

Absorption piece, described absorption piece are provided with fartherly and have than the recording medium from the track of the liquid that nozzle plate sprayed and be used to absorb the sorbent surface that is not applied to the liquid on the recording medium;

The waste liquid absorption piece, the capillarity of described waste liquid absorption piece is higher than the capillarity of absorption piece, and on the connection surface, contact with described absorption piece, described waste liquid absorption piece is used for sucking the liquid that has been absorbed in absorption piece, and described connection surface is absorption piece and the contacted surface of waste liquid absorption piece; And

The electrical potential difference generation device is used for producing electrical potential difference and will be attracted to described connections by electrophoresis from the solute of the liquid of described sorbent surface surperficial between the described sorbent surface of absorption piece and described connection surface.

2. liquid injection apparatus according to claim 1, wherein, an end of described electrical potential difference generation device is connected to around the surperficial connection face side electrode that is adjacent on the described absorption piece of described connection, is used to locate described connection surface.

3. liquid injection apparatus according to claim 2, wherein, an other end of described electrical potential difference generation device is connected to the sorbent surface lateral electrode of being arranged to adjacent to described sorbent surface.

4. liquid injection apparatus according to claim 2, wherein, an other end of described electrical potential difference generation device is connected to the sorbent surface lateral electrode of being arranged to adjacent to the rear surface of described sorbent surface.

5. liquid injection apparatus according to claim 2, wherein, an other end of described electrical potential difference generation device is connected to the sorbent surface lateral electrode, and described sorbent surface lateral electrode is embedded in the absorption piece.

6. liquid injection apparatus according to claim 1, wherein, also comprise outer electrical potential difference generation device, it is used for producing electrical potential difference between the described sorbent surface of described nozzle plate and described absorption piece, and will be from liquid electric attraction that nozzle plate sprayed to described sorbent surface.

7. liquid injection apparatus according to claim 6, wherein, described nozzle plate has conductibility, and an end of outer electrical potential difference generation device is connected to described nozzle plate.

8. liquid injection apparatus according to claim 7, wherein, an other end of described outer electrical potential difference generation device is connected to around connecting the surperficial connection face side electrode that is adjacent on the described absorption piece, to locate described connection surface.

9. liquid injection apparatus according to claim 7, wherein, an other end of described outer electrical potential difference generation device is connected to the sorbent surface lateral electrode of being arranged to adjacent to described sorbent surface.

10. liquid injection apparatus according to claim 7, wherein, an other end of described outer electrical potential difference generation device is connected to the sorbent surface lateral electrode of being arranged to adjacent to the rear surface of described sorbent surface.

11. liquid injection apparatus according to claim 6, wherein, described electrical potential difference generation device and described outer electrical potential difference generation device comprise that respectively independent electrical potential difference produces circuit.

12. liquid injection apparatus according to claim 6, wherein, described electrical potential difference generation device and described outer electrical potential difference generation device also comprise:

Single electrical potential difference produces circuit; And

Switching device shifter, described switching device shifter are used for switching between first connection status and second connection status alternatively, and wherein: in first connection status, wherein the electrical potential difference output that produces circuit is coupled to the sorbent surface of described absorption piece and is connected surperficial; In second connection status, wherein described nozzle plate and described absorption piece are coupled in the output of electrical potential difference generation circuit.

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