JP4677907B2 - Liquid ejector - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus. More specifically, the present invention relates to a liquid ejecting apparatus that attaches liquid ejected from an opening of a nozzle plate attached to a liquid ejecting head to a recording material.

  In the liquid ejecting apparatus, when the liquid is adhered without leaving a margin at the peripheral portion of the recording material, an area that is slightly larger than the size of the recording material in anticipation of the inevitable misalignment of the recording material and the liquid ejecting head. Is ejected with respect to the liquid. For this reason, in the vicinity of both side edge portions and front and rear end portions of the recording material, the liquid is also discharged to the region where the recording material does not exist. If liquid that cannot adhere to the recording material is left unattended, not only the liquid ejecting device itself but also the unexpected area on the recording material and the user's hand may be contaminated. Various techniques have been proposed for storing them.

Patent Document 1 below proposes a mechanism for guiding the liquid that has been deposited without adhering to the recording material and adhered to the platen to a waste liquid container different from the platen.
JP 11-320891 A

  In the liquid ejecting apparatus described in Patent Document 1, the liquid that has come in is directly received by the platen. At this time, if an excessive liquid droplet is received in a state where the liquid is already present on the platen surface, a droplet is generated due to an impact when the liquid droplet collides, and the periphery of the platen and the recording material are contaminated. Therefore, Patent Document 1 proposes that a through hole is provided in the platen, and the liquid in the platen is guided to the separately provided waste liquid container through the through hole.

  However, since the amount of liquid deposited on the platen is not constant, sometimes the discharge does not catch up and may stay on the platen. If a liquid droplet further collides with the staying waste liquid, a liquid splash occurs and the surroundings are contaminated. Further, when the discharge of the liquid from the platen is delayed, the liquid medium may evaporate and a non-volatile component may remain on the platen. If non-volatile components are accumulated on the platen, there will be a problem of contaminating a recording material to be handled later, and also a problem that the flow of the waste liquid is more likely to be stagnated due to irregularities on the surface of the waste liquid flow path on the platen. Arise.

  In view of this, it has been proposed and implemented to dispose an absorbing member made of a porous material on the surface of the platen for the purpose of preventing the occurrence of splashing of the liquid and absorbing the excess liquid. However, the absorbing member itself has a suction force due to capillary action. Therefore, it is not possible to guide the liquid to the waste liquid absorbent by the technique described in Patent Document 1. Therefore, it has also been proposed to further equip a waste liquid absorbent material having a higher capillary force and a larger absorption capacity, and sequentially suck the liquid absorbed by the absorbent member into the waste liquid absorbent material to prevent saturation of the absorbent member. Yes.

Patent Document 2 listed below discloses a liquid ejecting apparatus including a porous absorbent member.
JP 2004-202867 A

  The liquid ejecting apparatus disclosed in Patent Literature 2 includes an absorbing member housed in a platen, and receives and absorbs liquid that has not adhered to the recording material by the absorbing member. In this liquid ejecting apparatus, a metal member serving as an electrode is further disposed on the surface of the absorbing member, and an electric field is formed between the metal nozzle plate that discharges the liquid and the electrode. Since the droplets discharged from the nozzle plate are charged to the same polarity as the nozzle plate, they are directed to the electrode without being decelerated by the Coulomb force acting between itself and the electric field, and are eventually adsorbed by the electrode. The droplet adsorbed on the electrode is finally absorbed by the absorbing member.

  The action of the electric field as described above is aimed at collecting aerosols. In other words, the aerosol is a droplet that floats without adhering to the recording material and without reaching the platen.

  Due to the demand for improving the recording accuracy, the liquid droplets ejected from the liquid ejecting apparatus are miniaturized to about several pl. Since such a fine droplet has a very small mass, once ejected, the kinetic energy is rapidly lost due to the viscous resistance of the atmosphere. For example, a droplet of less than 8 pl has a velocity of almost zero when it travels about 3 mm in the atmosphere. Since the distance between the recording material and the absorbing member and the gap between the nozzle plate and the recording material is about 3 to 5 mm, some of the droplets that did not adhere to the recording material reach the absorbing member. Loss kinetic energy before. Droplets that have lost their kinetic energy are almost balanced by the drop motion due to gravitational acceleration and the viscous resistance of the atmosphere, and it takes a long time to drop.

  If the discharge speed is increased for the purpose of extending the reach distance of the droplet, the influence of the viscous resistance of the atmosphere acting on the droplet is further increased and the reach distance is shortened. Further, when the ejection speed is increased, extremely fine droplets called satellite ink that are generated when the droplets are detached from the nozzle plate are likely to be generated.

  Further, in the liquid ejecting apparatus, an operation called flushing is periodically repeated. Flushing is an operation in which the liquid ejecting head is operated in a state where there is no recording object, and the liquid is so-called air shot. By such an operation, the thickened liquid is removed from the nozzle with a small discharge amount. However, since the liquid discharged during the flushing is consumed only for the flushing and does not contribute to the recording on the recording material, small droplets are ejected to save the liquid consumption. Further, since the time required for flushing decreases the throughput of the original printing operation, the liquid is discharged from all the nozzles within a short time in the flushing. Even in such a flushing operation, a large amount of satellite ink is generated.

  Many of the satellite inks generated as a result of various phenomena as described above float around the liquid ejecting head moving area and become aerosol. Part of the aerosol floats to the outside of the liquid ejecting apparatus and adheres to the periphery of the liquid ejecting apparatus. In addition, most of the aerosol eventually adheres to each part in the liquid ejecting apparatus. Here, when the aerosol adheres to the transport path of the recording material such as the platen, the recording material transported next is contaminated. In addition, when the aerosol adheres to the electric circuit, the linear scale, or various optical sensors of the liquid ejecting apparatus, the apparatus itself may malfunction. Further, when the user touches the aerosol, the user's hand is also soiled.

  As described above, in the liquid ejecting apparatus, an absorbing member formed of a porous material may be used for the purpose of absorbing the liquid that reaches the platen without adhering to the recording material. However, since the absorbing member using the porous material itself has a liquid holding force due to capillary action, a certain amount of liquid continues to be held in the absorbing member. However, since the volatile component of the retained liquid evaporates in the vicinity of the surface of the absorbing member, the non-volatile component is concentrated in the vicinity of the surface. For this reason, the absorbing member may be clogged, and the intended function of the absorbing member for receiving the liquid without causing splashing may be lost. In addition, since the non-volatile component accumulated on the surface of the absorbing member often contains a dye component, this causes a problem that the recording material supplied next is contaminated.

  In order to solve the above-described problem, as one form, a liquid ejecting head including a conductive nozzle plate including an opening for discharging liquid to a recording material, and recording on a track of the liquid discharged from the nozzle plate An absorbing member having an absorbing surface that is disposed farther than the object and absorbs liquid that has not landed on the recording material, and has a higher capillary force than the absorbing member, and is connected to the absorbing member at a connecting surface different from the absorbing surface. A potential difference is generated between the waste liquid absorber that absorbs the liquid absorbed by the absorbing member and the connection surface of the nozzle plate and the absorbing member, and the liquid discharged from the nozzle plate is electrically directed toward the absorbing surface. There is provided a liquid ejecting apparatus that includes an attracting means and a potential difference generating means for attracting a solute in the liquid inside the absorbing member by electrophoresis from the absorbing surface toward the connecting surface. In this liquid ejecting apparatus, the aerosol is attracted to the absorbing member by the electric field formed between the nozzle plate and the absorbing member, and the solute contained in the liquid is further moved to the waste liquid absorbing material side by the electric field formed inside the absorbing member. Be attracted. Accordingly, the aerosol that remains floating is reduced, and the nonvolatile solute is not concentrated in the vicinity of the surface of the absorbing member.

  According to another embodiment, in the liquid ejecting apparatus, the potential difference generating means includes a connection surface side electrode that contacts the absorbing member in the vicinity of the connection surface and positions the connection surface. Accordingly, the absorbing member can be reliably positioned without increasing the number of parts, and the liquid can be smoothly absorbed from the absorbing member to the waste liquid absorbing material.

  According to another embodiment, in the liquid ejecting apparatus, the potential difference generating unit generates an electric potential difference between the nozzle plate and the absorbing surface, and electrically draws the liquid to the absorbing member, and the absorbing member And a potential difference generating means in the absorbing member that generates a potential difference between the absorption surface and the connection surface and attracts a solute in the liquid to the connection surface side by electrophoresis. Thereby, an electric field for attracting the aerosol to the absorbing member and an electric field for attracting the solute in the liquid to the waste liquid absorbing material side can be set under optimum conditions.

  According to still another embodiment, in the liquid ejecting apparatus, the potential difference generating means includes an absorption surface side electrode disposed adjacent to the absorption surface. Thereby, the electric potential of the absorption member surface can be set appropriately, and a desired electric field can be easily formed.

  According to still another embodiment, in the liquid ejecting apparatus, the potential difference generating means includes an absorption surface side electrode disposed adjacent to the back surface of the absorption surface. Thereby, the liquid does not directly adhere to the absorption surface side electrode, and the desired performance is maintained for a long time.

  Further, as another form, a liquid ejecting head having a conductive nozzle plate including an opening for discharging liquid to the recording material, and a farther than the recording material on the track of the liquid discharged from the nozzle plate An absorbing member having an absorbing surface that absorbs liquid that has not landed on the recording material, and has a higher capillary force than the absorbing member, and contacts the absorbing member at a connecting surface different from the absorbing surface to the absorbing member. A waste liquid absorbent that absorbs absorbed liquid from the absorbent member, a common potential difference generating means that generates a potential difference between a pair of outputs, and a liquid by applying the output of the common potential difference generating means between the nozzle plate and the absorption surface A first connection state in which the solute in the liquid is attracted to the connection surface side by electrophoresis by applying the output of the common potential difference generating means between the absorption surface and the connection surface. A liquid ejecting apparatus and a switching means for selectively realizing a connection state is provided. As a result, in this liquid ejecting apparatus, the aerosol is attracted to the absorbing member by the electric field formed between the nozzle plate and the absorbing member, and further, the solute contained in the liquid is absorbed by the waste liquid by the electric field formed inside the absorbing member. Attracted to the material side. Accordingly, the aerosol that remains floating is reduced, and the nonvolatile solute is not concentrated in the vicinity of the surface of the absorbing member. Furthermore, since one potential difference generating means is switched and used, the number of parts is reduced, which contributes to cost reduction and downsizing of the product.

  The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims, and all combinations of features shown in the embodiments are means for solving the invention. It is not always essential.

  FIG. 1 is a perspective view showing an overview of an ink jet recording apparatus 11 which is one embodiment of a liquid ejecting apparatus. As shown in the figure, the ink jet recording apparatus 11 includes a lower case 20 that forms the base of the entire apparatus, an upper case 22 that forms a casing together with the lower case 20, and a hopper mounted on the rear part of the lower case 20. 10 and a discharge tray 30 formed on the front surface of the lower case 20. The ink jet recording apparatus 11 includes a platen 400 disposed horizontally in the lower case 20 and a carriage 200 disposed above the platen 400.

  In the ink jet recording apparatus 11 as described above, the recording object 300 accommodated in the hopper 10 is sent one by one onto the platen 400 by a carry-in unit (not shown), and further discharged by a discharge unit (not shown). It is sent out to the tray 30. In the ink jet recording apparatus 11, the carriage 200 reciprocates above the platen 400 in a direction orthogonal to the conveyance direction of the recording material 300. Therefore, by alternately transporting the recording medium 300 and reciprocating the carriage 200, the entire upper surface of the recording medium 300 can be scanned by the carriage 200, and a recording operation can be performed in an arbitrary area on the recording medium 300.

  FIG. 2 is a perspective view showing the internal mechanism 12 of the ink jet recording apparatus 11 shown in FIG. As shown in the figure, the internal mechanism 12 includes a frame 100 disposed substantially vertically rearward, and a pair of side surface portions 110 and 111 extending forward in parallel from both side end portions of the frame 100. It is formed approximately inside the region to be defined.

  As shown in the figure, the carriage 200 is supported by a guide shaft 220 that passes through the carriage 200. An end of the guide shaft 220 is supported by the side surface portion 110 and the side surface portion 111, and is arranged in parallel to the frame 100. Accordingly, the carriage 200 can move horizontally along the guide shaft 220.

  A pair of pulleys 242 and 244 and a timing belt 230 hung on the pulleys 242 and 244 are disposed on the front surface of the frame 100 behind the carriage 200. One pulley 244 is rotationally driven by a carriage motor 246. The timing belt 230 is coupled to the rear portion of the carriage 200. Accordingly, the carriage 200 can be reciprocated according to the operation of the carriage motor 246.

  The carriage 200 is loaded with an ink cartridge 250 and includes a recording head 210 on the lower surface thereof. The recording head 210 includes a nozzle plate 260 made of a conductive material including an opening for ejecting ink. Therefore, ink is ejected downward from the carriage 200.

  Furthermore, the carriage 200 is coupled to the electronic circuit 120 behind the frame 100 via a tape-shaped multicore cable 270. Since the multi-core cable 270 flexes flexibly as the carriage 200 moves, the multi-core cable 270 does not prevent the carriage 200 from reciprocating.

  A platen 400 is disposed below the area through which the carriage 200 passes. The platen 400 supports the recording medium 300 that passes under the carriage 200 from below, and maintains a constant distance between the lower surface of the nozzle plate 260 and the upper surface of the recording object 300. Further, a depressed portion 410 is formed on the upper surface of the platen 400, and a porous material absorbing member 420 is accommodated in the depressed portion 410. The absorbing member 420 receives ink ejected from the recording head 210 in an area where the recording medium 300 does not exist. There is an interval of about 3 to 5 mm between the nozzle plate 260 and the absorbing member 420.

  Ink adheres to the absorbing member 420 as the operating time elapses. When the recording material 300 comes into contact with the absorbing member 420 to which the ink has adhered, the recording material 300 is contaminated by the ink. Therefore, a protrusion-like portion is formed on the upper surface of the platen 400, and the recording object 300 is lifted from below to maintain a distance from the absorbing member 420.

  Further, the absorption capacity of the absorption member 420 incorporated in the platen 400 is limited. Therefore, a larger waste liquid absorbent 600 is disposed below the platen 400, and a part of the absorbent member 420 is in contact therewith. The waste liquid absorbing material 600 is selected from a material having a large liquid absorbing power due to capillary action, and can absorb ink from the absorbing member 420 that has come into contact therewith.

  Further, a conveyance roller 310 is disposed behind the platen 400. The conveyance roller 310 is driven and rotated by a conveyance motor 320 disposed behind the frame 100, and sends the recording material 300 onto the platen 400 in cooperation with a driven roller (not shown). As described above, since the carriage 200 can reciprocate in the direction orthogonal to the conveyance direction of the recording medium 300, the conveyance of the recording medium 300 and the reciprocation of the carriage 200 are alternately performed, and the recording head 210 on the lower surface of the carriage 200 is moved. By operating intermittently, ink can be ejected and adhered to an arbitrary region on the recording material 300.

  Furthermore, a cap member 500 is disposed on the side corresponding to the side surface 110 with respect to the platen 400. The cap member 500 can move up and down, and rises when the carriage 200 stops at the home position close to the side surface portion 110 to seal the surface of the nozzle plate 260. Further, the inside of the cap member 500 is coupled to the pump unit 510, and the ink attached to the surface of the nozzle plate 260 can be sucked. The ink sucked by the pump unit 510 is finally absorbed by a dedicated cap side waste liquid absorber through a pipe (not shown).

  A wiping means 520 is disposed between the platen 400 and the cap member 500. When the carriage 200 released from the cap member 500 passes above, the wiping means 520 wipes and cleans the lower surface of the nozzle plate 260.

  FIG. 3 is a diagram schematically showing the structure and function of the satellite ink and solute collecting mechanism 13 in the ink jet recording apparatus 11. As shown in the drawing, the nozzle plate 260 connected to one end of the potential difference generating means 700 is formed with a plurality of openings 262 for ejecting ink. Further, below the nozzle plate 260, a platen 400 and a waste liquid absorber 600 are sequentially arranged.

  An absorbing member 420 is accommodated inside the depressed portion 410 of the platen 400. Here, the upper surface of the absorbing member 420 is an absorbing surface that receives ink. Further, a part of the absorbing member 420 is inserted into a hole formed in the bottom of the platen 400 and extends downward, and the vicinity of the lower end thereof is in contact with the upper surface of the waste liquid absorbing material 600 as a connection surface. The waste liquid absorbent 600 is disposed at an interval of about 5 to 20 mm with respect to the absorbent member 420.

  Further, the connection surface side electrode 440 is attached to the lower end of the absorbing member 420. The connection surface side electrode 440 is connected to the other end of the potential difference generating means 700 and contributes to the application of the potential difference, and also has a physical function of holding and positioning the lower end of the absorbing member 420.

  Examples of the material of the connection surface side electrode 440 include metals that are corrosion resistant to the ink of the ink jet recording apparatus 11, such as gold, stainless steel, nickel, or copper plated with these metals. can do.

Further, the absorbing member 420 is a conductive material having a surface resistance of 10 ⁸ Ω or less. The material is foamed after mixing a conductive material such as metal or carbon into a resin such as polyethylene or polyurethane. A material obtained by attaching a conductive material such as metal or carbon to a resin foam material such as polyethylene, polyurethane, or the like can be used. In addition, a resin foam material such as polyethylene or polyurethane impregnated with an electrolyte solution can be used as the absorbing member 420.

  In the satellite ink and solute collecting mechanism 13 shown in FIG. 3, the nozzle plate 260 has a plurality of openings 262 for ejecting ink. Usually, a recording object 300 supported by the platen 400 from below is present immediately below the nozzle plate 260. Accordingly, the droplet 268 ejected from the nozzle plate 260 adheres to the recording material 300.

  On the other hand, when ink is allowed to adhere to the edge of the recording object 300 without a margin, the recording object 300 exists immediately below a part of the openings 262 at the side edge and the front and rear ends of the recording object 300. There are things that do not. In such a case, the kinetic energy given to the droplets 266 by discharging from the opening 262 is quickly lost due to the viscous resistance of the atmosphere, and some of the droplets 266 completely disappear before reaching the absorbing member 420. Lost. Further, since the mass of the droplet 266 is very small, the drop motion due to gravitational acceleration and the viscous resistance force due to the atmosphere are almost balanced, and the drop velocity of the droplet 266 becomes extremely slow. Thus, aerosol floating below the nozzle plate 260 is generated.

Collecting mechanism 13 shown in FIG. 3, the nozzle plate 260 and the absorbing electric field E ₁ between the member 420, an electric field E ₂ between the absorbent member 420 the lower end is a connecting surface and the absorbing member 420 the upper surface which is absorbing surface Are formed respectively. That is, one end of the potential difference generating means 700 is connected to the nozzle plate 260 and the other end of the potential difference generating means 700 is connected to the connection surface side electrode 440, and a potential difference V is generated between them. In addition, a potential difference is generated between the connection surface of the absorbing member 420 and the absorbing surface due to a voltage drop corresponding to the DC resistance value of the absorbing member 420. Therefore, an electric field E ₁ corresponding to the potential difference and distance between the nozzle plate 260 and the absorbing member 420 is formed. Also between the absorbing surface and the connecting surface of the absorbing member 420, an electric field E ₂ in response to both the potential difference and distance are formed.

  In the ink jet recording apparatus 11, the ink pushed out from the opening 262 becomes an ink column 264 that hangs down from the nozzle plate 260 at the moment immediately before the droplet 266 is formed. At this time, a so-called lightning rod effect occurs between the tip A of the ink column 264 and the lower surface of the nozzle plate 260 near the ink column 264. That is, the lightning rod effect referred to here is a region B on the surface of the nozzle plate 260 surrounded by a cone having an apex angle of 50 ° to 60 ° with the tip A (lower end in the figure) of the ink column 264 as a vertex. It contributes to the charging of H.266. Due to the lightning rod effect, the droplet 266 is charged with a charge larger than the charge corresponding to the horizontal cross-sectional area of the ink column 264.

The ink column 264 eventually leaves the nozzle plate 260 and becomes a droplet 266, which is charged with the charge q accumulated by the lightning rod effect as described above. Accordingly, the droplet 266 having the electric charge q obtains kinetic energy by the Coulomb force Fe (qE ₁ ) from the electric field E ₁ and can move downward without reaching the absorbing member 420 without being decelerated.

Further, an electric field E ₂ is formed inside the absorbing member 420. Solutes in the liquid have an inherent charge in each composition. Moreover, what has an electric charge produces the electrophoresis which moves toward the pole opposite to the electric charge in an electric field. Therefore, if the polarity of the connection surface side electrode 440 is selected so as to be opposite to the charge of the solute in the ink contained in the absorbing member 420, the solute can be attracted to the connection surface side electrode 440. Thus, the solute in the ink can be moved to the connection surface side electrode 440 as shown by the distribution of black circles in the absorbing member 420 in the drawing.

Incidentally, valid electrophoresis in the interior of the absorbent member 420 is expressed in the state between the electrodes sufficient amount of ink in the absorbing member 420 to form a being absorbed electric field E ₂ is coupled with a solvent ink. On the other hand, when the ink jet recording apparatus 11 starts operating, the amount of ink contained in the absorbing member 420 is very small. For this reason, effective electrophoresis may not occur at the beginning of operation. However, when the absorbing member 420 contains a certain amount of ink due to the continuation of the recording operation, the solvent continuously exists in the absorbing member 420, so that the solute is moved into the absorbing member 420 by electrophoresis. The solute is prevented from being concentrated and accumulated on the surface of the absorbing member 420. The solute that has reached the waste liquid absorbent 600 is sequentially absorbed from the absorbent member 420. Therefore, no solute remains in the absorbing member 420, and performance deterioration of the absorbing member 420 due to accumulation of the solute is prevented.

  Moving the solute toward the connection surface side electrode 440 inside the absorption member 420 with limited capacity simultaneously means that the solute near the absorption surface of the absorption member 420 is reduced. Therefore, even if the volatile component evaporates on the absorption surface of the absorption member 420, the solute that is a nonvolatile component in the ink is not accumulated near the absorption surface. Further, on the connection surface side of the absorbing member 420, the solute is absorbed together with the medium by the waste liquid absorbing material 600 having a strong absorbing power. Therefore, no solute is accumulated at the lower end of the absorbing member 420. As a material for the waste liquid absorbent 600, a compressed body of pulp or chemical fiber, or a material mixed with a polymer absorbent can be preferably used.

FIG. 4 shows another embodiment of the satellite ink and solute collection mechanism 13. In addition, the same referential mark is attached | subjected to the same component as FIG. 3, and the overlapping description is abbreviate | omitted. As shown in the figure, in this embodiment, a net-like absorption surface side electrode 430 is disposed on the upper surface of the absorption member 420. Also, an aerial potential difference generating means 710 that generates a potential difference V ₁ between the nozzle plate 260 and the absorbing surface side electrode 430 and an in-absorbing member potential difference generating a potential difference V ₂ between the absorbing surface and the connecting surface of the absorbing member 420. There is a unique feature in that a pair of potential difference generating means with the means 720 is provided separately.

The structure described above, the electric field E ₁ between the nozzle plate 260 and the absorbing surface side electrode 430, an electric field E ₂ between the absorbing surface side electrode 430 and the connecting surface side electrode 440, it can be optimally set respectively it can. Therefore, it is possible to efficiently perform the adsorption of the aerosol to the absorption member 420 and the movement of the solute in the absorption member 420 to the connection surface side.

  In addition, as a material of the absorption surface side electrode 430 used here, these metals were plated on metals that are corrosion resistant to the ink of the ink jet recording apparatus 11, such as gold, stainless steel, nickel, or copper. The thing can be illustrated. In addition, as a member, a wire or plate having a diameter of about 0.1 mm to 0.5 mm formed of these materials and arranged in parallel at intervals of about 0.5 mm to 4 mm or a combination in a lattice shape is used. Can be used. It is preferable that the member used as the absorbing surface side electrode 430 has a passing region that is large enough to allow the flying ink to pass through the lower part of the absorbing member 420. Examples of the material of the absorbing member 420 include, but are not limited to, a foamed resin such as polyethylene and polyurethane.

  In addition, the solute collecting operation is efficient when executed immediately after the recording operation of the ink jet recording apparatus 11 is completed. Therefore, a timer (not shown) for controlling the potential difference generating means 720 connected to the solute collecting mechanism 13 side is provided, and the solute collecting mechanism for a certain period of time from several minutes to about 1 hour after the recording operation of the ink jet recording apparatus 11 is completed. It is preferable to continue operating 13. As a result, the ink solute is removed from the absorbing member 420 immediately after the recording operation of the ink jet recording apparatus 11 is completed, so that the solute component is accumulated in the absorbing member 420 even when the recording operation is not executed for a long period of time thereafter. There is nothing to do.

  FIG. 5 is a graph showing the relationship between the applied electric field and the number of aerosols generated in the embodiment shown in FIG. That is, with the output of the absorbing member potential difference generating means 720 kept constant, the air potential difference generating means 710 forms electric fields of various strengths between the nozzle plate 260 and the absorbing surface side electrode 430 and performs the recording operation. The amount of aerosol generated as a result was measured and plotted. At the time of measurement, the average size of the droplets was set to 7 pl, and a recording operation was performed on 5 A4 size recording materials over a period of 7 minutes and 38 seconds from the start of printing. The total number of aerosols that could be counted before the minutes passed was divided by 8 to give the number of aerosols per minute. As shown in the figure, it can be seen that when the electric field exceeds 25 kV / m, the number of aerosols starts to decrease remarkably and sufficient aerosol collection has been carried out as compared with the case where there is no electric field at all.

  FIG. 6 is a graph in which the number of aerosols (vertical axis) and the applied electric field (horizontal axis) in the graph shown in FIG. 5 are logarithmically displayed. As can be seen from the figure, when the applied electric field is increased, the number of aerosols continues to decrease, but the rate of the decrease gradually decreases. In addition, when the applied electric field exceeds 250 kV / m, the degree of decrease is disturbed, and it can be seen that the input electric power is not necessarily utilized effectively.

  FIG. 7 is a diagram showing a modification of the embodiment shown in FIG. As shown in the figure, the collection mechanism 13 includes a single potential difference generating unit 700 and a switching unit 800 that can switch the output destination of the potential difference generating unit 700 under the control of the switching signal. That is, the switching means 800 causes the potential difference V generated by the potential difference generating means 700 to be either between the nozzle plate 260 and the absorption surface side electrode 430 or between the absorption surface side electrode 430 and the connection surface side electrode 440. Can be selectively applied.

Switching between the period in which the recording head 210 is operated and ink is being ejected from the nozzle plate 260 and the period immediately thereafter by the switching signal so that a potential difference V is generated between the nozzle plate 260 and the absorbing surface side electrode 430. Means 800 is transitioned to the first state. At this time, since the electric field E ₁ is generated between the nozzle plate 260 and the absorption surface side electrode 430, the aerosol is attracted to the absorption member 420.

Next, after the ink ejection is completed, the switching unit 800 is changed to the second state by the switching signal so that the 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 E ₂ is generated between the connecting surface side electrode 440 and the absorbing surface side electrode 430, the solute contained in the ink is moved to the connecting surface side inside of the absorbing member 420, the absorption surface side Solute decreases.

  Thus, in this embodiment, since the single potential difference generating means 700 is used by switching to aerosol collection and solute movement, the number of costly potential difference generating means mounted can be reduced, and at the same time, the inkjet type It is also possible to save power necessary for the operation of the recording apparatus 11.

  FIG. 8 is a diagram showing a modification of the satellite ink and solute collecting mechanism 13 shown in FIG. In the figure, the same reference numerals are assigned to the same components as those in the other drawings, and redundant explanation is omitted.

  As shown in the figure, the collecting mechanism 13 is adjacent to the absorbing member 420 in the platen 400 with an absorbing surface side electrode 431 formed by a conductor plate laid on the bottom of the depressed portion 410 of the platen 400. There are unique features. In other words, in this embodiment, the absorption surface side electrode 431 is disposed on the back surface of the surface of the absorption member 420 facing the nozzle plate 260. Moreover, it is preferable that the material of the absorption member 420 used here has electroconductivity. The rest of the configuration is the same as that of the embodiment shown in FIG.

  In this embodiment, the absorbing surface side electrode 431 covers the entire bottom surface of the depressed portion 410 of the platen 400, and the absorbing member 420 having substantially the same shape is accommodated thereon. Since the entire lower surface of the absorbing member 420 is in contact with the absorbing surface side electrode 431 as described above, the absorbing member 420 and the absorbing surface side electrode 431 are electrically connected in a wide area. Therefore, even if there is an electrically discontinuous portion in the internal structure of the absorbing member 420, the entire absorbing member 420 has a uniform potential substantially equal to the absorbing surface side electrode 431. Further, since the absorbing surface side electrode 431 is disposed on the back surface of the absorbing member 420, ink does not adhere directly, and the desired performance can be maintained over a long period of time.

  Examples of the material of the absorbing surface side electrode 431 include metals that are corrosion resistant to the ink of the ink jet recording apparatus 11, such as gold, stainless steel, and nickel. In addition to the form of using electrode members made of plate materials of these materials, wire materials or foil materials, wire materials plated with these metals, plate materials or foil materials, or nets or lattices combining these materials It may be a member formed in a shape. Furthermore, a conductive coating layer, a plating layer, a thick film layer, a thin film layer, or the like formed directly on the depression 410 of the platen 400 may be used.

Also in this embodiment, the potential difference V is generated between the nozzle plate 260 and the absorption surface side electrode 431 during the period in which the recording head 210 is operated and ink is being ejected from the nozzle plate 260 and the period immediately thereafter. Then, the switching unit 800 is shifted to the first state. At this time, since the electric field E ₁ is generated between the nozzle plate 260 and the absorption surface side electrode 431, the aerosol is attracted to the absorption member 420.

Next, after the ink ejection is completed, the switching unit 800 is shifted to the second state so that a potential difference V is generated between the absorption surface side electrode 431 and the connection surface side electrode 440. At this time, since the electric field E ₂ is generated between the connecting surface side electrode 440 and the absorbing surface side electrode 431, the solute contained in the ink is moved to the connecting surface side inside of the absorbing member 420, the absorption surface side Solute decreases.

  As described in detail above, the ink jet recording apparatus 11 has a function of moving the solute contained in the ink in the absorbing member 420 to the waste liquid absorbing material 600 side using an electric field. Therefore, no solute is accumulated on the surface of the absorbing member 420, and unnecessary ink that has not contributed to recording on the recording medium 300 can be smoothly absorbed and discarded.

  In addition, as a specific example of the liquid ejecting apparatus that can be an embodiment of the present invention, an electrode forming apparatus or a biochip in the production of a color material ejecting apparatus, an organic EL display, an FED (surface emitting display), etc. Examples include a sample ejection head used for manufacturing, but are not limited thereto.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

FIG. 2 is a perspective view of the overall appearance of the ink jet recording apparatus 11. FIG. 3 is a perspective view showing the vicinity of an internal mechanism 12 of the ink jet recording apparatus 11. FIG. 3 is a view showing a collecting mechanism 13 of the ink jet recording apparatus 11. The figure which shows other embodiment of the collection mechanism. The graph which shows the relationship between the applied electric field and aerosol number in embodiment. 6 is a graph showing the number of aerosols in the graph shown in FIG. The figure which shows other embodiment of the collection mechanism. The figure which shows other embodiment of the collection mechanism.

Explanation of symbols

10 hopper, 11 ink jet recording apparatus, 12 internal mechanism, 13 collecting mechanism, 20 lower case, 22 upper case, 30 discharge tray, 100 frame, 110, 111 side portion, 120 electronic circuit, 200 carriage, 210 recording head, 220 Guide shaft, 230 Timing belt, 242 and 244 Pulley, 246 Carriage motor, 250 Ink cartridge, 260 Nozzle plate, 262 Opening, 264 Ink column, 266, 268 Droplet, 270 Multi-core cable, 300 Recorded object, 310 Transport roller , 320 conveying motor, 400 platen, 410 depression, 420 absorbing member, 430, 431 absorbing surface side electrode, 440 connecting surface side electrode, 500 cap member, 510 pump unit, 520 wiping means, 60 Waste liquid absorbing material, 700 potential difference generating means, 710 aerial potential difference generating means 720 absorbing member potential difference generating means, 800 switching unit

Claims (3)

A liquid ejecting head including a conductive nozzle plate including an opening for discharging liquid to a recording material;
An absorbing member having an absorbing surface that is disposed farther than the recording material on the track of the liquid discharged from the nozzle plate and absorbs the liquid that has not landed on the recording material;
A waste liquid absorbing material that has a higher capillary force than the absorbing member and that absorbs the liquid absorbed by the absorbing member in contact with the absorbing member at a connection surface different from the absorbing surface;
Common potential difference generating means for generating a potential difference between a pair of outputs;
A first connection state in which the output of the common potential difference generating means is applied between the nozzle plate and the absorption surface to electrically attract the liquid to the absorption member, and the common between the absorption surface and the connection surface A liquid ejecting apparatus comprising: a switching unit that selectively realizes a second connection state in which an output of the potential difference generating unit is applied and the solute of the liquid is attracted to the connection surface side by electrophoresis. 2. The liquid according to claim 1, wherein the switching unit realizes the first connection state so that a potential difference is generated between the nozzle plate and the absorbing surface during a period in which ink is ejected from the nozzle plate. Injection device . The switching unit realizes the second connection state such that a potential difference is generated between the absorption surface side and the connection surface side in a period in which the ejection of ink from the nozzle plate is stopped. The liquid ejecting apparatus according to 1 or 2 .

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