JP4604756B2 - 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. Therefore, an absorbing member is disposed at a position facing the liquid ejecting head in the direction in which the liquid is discharged, and excess liquid that cannot adhere to the recording material is absorbed by the absorbing member, so that excess liquid is scattered. This prevents the surrounding area from being contaminated.

  Note that the recording material may be stretched and wrinkled due to liquid adhesion. When the stretched recording material comes into contact with the absorbing member due to the bending of its own wrinkles, the liquid already absorbed by the absorbing member adheres to the recording material and is contaminated. In view of the elongation of the recording material, a gap of about 2 to 4 mm is provided between the recording material and the absorbing member in the liquid ejecting apparatus. A gap of about 1 mm is also provided between the liquid jet head and the recording material.

  On the other hand, due to a demand for improving the resolution of a recorded image, in recent liquid ejecting apparatuses, the droplets ejected from the opening of the nozzle plate are miniaturized to about several pl. Since such a fine droplet has a very small mass, once it is ejected, it rapidly loses kinetic energy due to the viscous resistance of the atmosphere. Specifically, for example, a droplet of less than 8 pl has a velocity of substantially zero when it travels about 3 mm in the atmosphere. The fine droplets that have lost their kinetic energy are almost balanced by the drop motion due to gravitational acceleration and the viscous resistance force of the atmosphere, and it takes a long time to finish dropping.

  In addition, for example, about a distance of about 3 to 5 mm obtained by adding a gap between the nozzle plate and the recording material to the interval between the recording material and the absorbing member, droplets can reach from the nozzle plate to the surface of the absorbing member. Even if the ejection speed of the liquid ejecting apparatus for a droplet of about 3 pl is intentionally increased, the viscous resistance of the atmosphere acting on the droplet further increases and the reach distance is shortened. Further, when the ejection speed is increased, very 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 of sending a drive signal to the liquid ejecting head in the absence of a recording object, and so-called shooting of liquid. By such an operation, the thickened liquid is removed from the nozzle with a small discharge amount. However, since the liquid ejected at the time of flushing is consumed only for flushing and does not contribute to the recording operation, small droplets are ejected to save 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.

  Most of the satellite ink generated as a result of various phenomena as described above becomes an aerosol that floats around the liquid ejecting head moving area. 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. In particular, when aerosol adheres to the transport path of a recording material such as a platen, the recording material transported next is contaminated. Furthermore, 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. Furthermore, when the user touches the aerosol, the user's hand is soiled.

The following patent document discloses a liquid ejecting apparatus having a function of actively collecting the aerosol.
JP 2004-202867 A

  In the liquid ejecting apparatus disclosed in this document, an absorbing member is disposed at a position facing the nozzle plate for the purpose of absorbing excess liquid that has not adhered to the recording material. In addition, a metal member serving as one electrode is disposed on the surface of the absorbing member, and a metal nozzle plate having an opening for discharging liquid is used as the other electrode. When different voltages are applied to these electrodes and nozzle plate, an electric field is formed between them. In addition, droplets ejected from the nozzle plate in such a liquid ejecting apparatus are charged to the same polarity as the nozzle plate when ejected from the nozzle plate. For this reason, since the liquid droplets floating as aerosols are also charged, they are directed to the electrode without being decelerated by the Coulomb force acting between itself and the electric field, and are adsorbed by the electrode having the opposite polarity to itself. . The droplet adsorbed on the electrode is sucked by capillary action and finally absorbed by the absorbing member.

  In the liquid ejecting apparatus as described above, the conductive liquid has the same potential as the electrode to which the voltage is applied. Therefore, the liquid accumulated in the waste liquid absorbent is also at the same potential as the electrode. On the other hand, a metal member is used for a frame which is a structural material of the liquid ejecting apparatus, and this metal member is normally grounded. For this reason, when the liquid accumulated in the waste liquid absorbent material touches the frame, a current flows between them. When such a short circuit between the frame and the liquid occurs, the voltage in the absorbing member drops, and the performance of liquid recovery due to the electric field decreases. In addition, the liquid may be electrolyzed by the electric current to generate flammable gas or smoke.

In order to solve the above-described problem, in a first aspect of the present invention, a liquid ejecting apparatus includes a conductive nozzle plate and ejects liquid from an opening of the nozzle plate to a recording material. And a guide portion that supports the liquid jet head, a conductive frame that supports the guide portion, and a nozzle plate in the direction in which the liquid is discharged, and absorbs liquid that has not landed on the recording material An absorbing member having porosity and conductivity, an electrode having the same shape as the absorbing member, the absorbing member being stacked, the entire lower surface of the absorbing member being touched and electrically connected to the absorbing member, and a nozzle A potential difference generating means for generating a potential difference between the plate and the electrode to electrically attract the liquid to the electrode side, and a void property lower than that of the absorbing member, and absorbing by at least partly contacting the absorbing member. Comprising a waste liquid absorbing material for holding the absorbed liquid member, accommodating the waste liquid absorbing material, and a holding portion having an electrical insulating property. Thereby, it is possible to prevent the waste liquid absorbent material that may be electrically connected to the electrode with the liquid from being short-circuited with another member that is electrically grounded in the liquid ejecting apparatus. Moreover, even if the absorbing member is discontinuous, the entire absorbing member has a uniform potential.

  The liquid ejecting apparatus further includes a cap that covers the nozzle plate of the liquid ejecting head, a tube that transports the liquid discharged to the cap, and a cap-side absorbent that absorbs and holds the liquid transported by the tube, The holding unit may electrically insulate the waste liquid absorbent from the cap side absorbent. Thereby, it is possible to prevent the nozzle plate and the waste liquid absorber from being short-circuited via the liquid in the tube.

  The liquid ejecting apparatus may further include a pump that conveys the liquid in the tube and a pump motor that drives the pump, and the holding unit may electrically insulate the waste liquid absorber from the pump motor. Thereby, it is possible to prevent the pump motor and the waste liquid absorber from being electrically short-circuited.

  The liquid ejecting apparatus may further include a guide unit that supports the liquid ejecting head and a conductive frame that supports the guide unit, and the holding unit may electrically insulate the waste liquid absorber from the frame. Thereby, it is possible to prevent the nozzle plate and the waste liquid absorber from being short-circuited via the frame and the guide portion.

  The liquid ejecting apparatus may further include a head motor that drives the liquid ejecting head along the guide unit, and the holding unit may electrically insulate the waste liquid absorbing material from the head motor. Thereby, it is possible to prevent the head motor and the waste liquid member from being electrically short-circuited.

  The liquid ejecting apparatus may further include a transport unit that transports the recording material and a transport motor that drives the transport unit, and the holding unit may electrically insulate the waste liquid absorber from the transport motor. Thereby, it can prevent that a conveyance motor and a waste-liquid absorber short-circuit electrically.

  The liquid ejecting apparatus may further include an electric circuit that controls the liquid ejecting head, and the holding unit may electrically insulate the waste liquid absorber from the electric circuit. Thereby, it is possible to prevent a short circuit between the electric circuit and the waste liquid absorber.

In the second aspect of the present invention, in the liquid ejecting apparatus, the platen that is disposed to face the nozzle plate in the direction in which the liquid is ejected and supports the recording material, the porosity that absorbs the liquid, and the conductivity An absorbent member having the same shape as the absorbent member, an electrode that is overlapped with the absorbent member, touches the entire lower surface of the absorbent member and is electrically connected to the absorbent member, and has a lower porosity than the absorbent member. And a waste liquid absorbent that retains the liquid absorbed by the absorbent member by at least part of contact with the absorbent member, and a holding portion that houses the waste liquid absorbent and has electrical insulation . Thereby, the effect similar to the 1st form can be acquired.

  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 scope of claims, and all combinations of features described in the embodiments are included. It is not necessarily essential for the solution of the invention.

  FIG. 1 is a perspective view showing an overview of an ink jet recording apparatus 11 which is an example of a liquid ejecting apparatus that can be an object of the present invention, and is drawn with an upper case 22 as a cover opened. As shown in FIG. 1, the ink jet recording apparatus 11 includes a lower case 20 serving as a base of the apparatus, an upper case 22 that forms a casing together with the lower case 20, and a hopper 10 attached to a rear portion of the lower case 20. 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 inside the casing.

  In the ink jet recording apparatus 11 as described above, the recording material 300 accommodated in the hopper 10 is sent out one by one onto the platen 400 by a transport 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, whereby a recording operation can be performed on an arbitrary area on the recording medium 300. it can.

  FIG. 2 is a perspective view showing the internal mechanism 12 of the ink jet recording apparatus 11 shown in FIG. 1 with the frame 100 and the side portions 110 and 111 extracted. 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, 111 extending from the both side end portions of the frame 100 toward the front in parallel with each other. It is formed inside the area defined by.

  As shown in FIG. 2, in this internal mechanism 12, 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 disposed 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 head 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 head 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 metal nozzle plate 260 including an opening for ejecting ink. Therefore, ink is ejected downward from the carriage 200.

  Furthermore, the carriage 200 is coupled to an electric 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 material 300 that passes under the carriage 200 from below, and maintains a constant distance between the nozzle plate 260 and the recording material 300. Further, a depressed portion 410 is formed on the upper surface of the platen 400, and the 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. A gap of about 2 to 4 mm is provided between the recording object 300 and the absorbing member 420 so that the recording object 300 and the absorbing member 420 are not contaminated by contact. Further, there is a gap of about 1 mm between the surface of the nozzle plate 260 and the surface of the recording material 300.

  Further, the absorbing member 420 built in the platen 400 is made of a material having a high porosity with an emphasis on the absorption speed on the surface thereof, so that the absorption capacity is limited. In view of this, the holding unit 800 that accommodates a larger waste liquid absorbent is disposed below the platen 400 to communicate with the waste liquid absorbent and the absorbent member 420. As the waste liquid absorbent material, a material with high absorption capacity due to capillarity is selected while the absorption capacity is regarded as important. Therefore, the waste liquid absorbing material can absorb a large amount of ink from the absorbing member 420.

  A conveyance roller 310 is disposed behind the platen 400. The conveyance roller 310 is driven by a conveyance motor 320 disposed behind the frame 100 and cooperates with a driven roller (not shown) to send the recording material 300 onto the platen 400. As described above, the carriage 200 can reciprocate in a direction orthogonal to the conveyance direction of the recording material 300. Accordingly, while conveying the recording medium 300 and reciprocating the carriage 200 alternately, the recording head 210 on the lower surface of the carriage 200 is intermittently operated to apply ink to an arbitrary area on the recording medium 300. Can be discharged and deposited.

  Further, in the internal mechanism 12, the cap member 500 is disposed on the side surface portion 110 side on the side of the platen 400. The cap member 500 can move up and down, and rises to seal the surface of the nozzle plate 260 when the carriage 200 stops at the home position close to the side surface portion 110. 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.

  Further, the inside of the cap member 500 is coupled to the pump unit 510. The pump unit 510 has a built-in pump motor 511 and can suck ink attached to the surface of the nozzle plate 260 through the cap member 500.

  FIG. 3 is a perspective view showing another embodiment of the internal mechanism 12 of the ink jet recording apparatus 11 shown in FIG. In FIG. 3, the same reference numerals are given to the same components as those in FIG.

  Also in this embodiment, 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 inside the area to be defined. The carriage 200 is supported by a guide shaft 220 that passes through the carriage 200, and can reciprocate horizontally along the guide shaft 220. A timing belt 230 hung on a pair of pulleys 242 (one not shown) is coupled to the rear part of the carriage 200 at the rear of the carriage 200. The carriage 200 can be reciprocated according to the operation of the timing belt 230.

  A platen 400 is disposed below the area through which the carriage 200 passes. The platen 400 supports the recording material 300 that passes under the carriage 200 from below, and maintains a constant distance between the nozzle plate 260 and the recording material 300. Further, a depressed portion 410 is formed on the upper surface of the platen 400, and the 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.

  A conveying roller 310 is disposed behind the platen 400, and cooperates with the driven roller 311 to send the recording material 300 onto the platen 400. As described above, the carriage 200 can reciprocate in a direction orthogonal to the conveyance direction of the recording material 300. Accordingly, while conveying the recording medium 300 and reciprocating the carriage 200 alternately, the recording head 210 on the lower surface of the carriage 200 is intermittently operated to apply ink to an arbitrary area on the recording medium 300. Can be discharged and deposited.

  Also in the internal mechanism 12, the cap member 500 is disposed on the side surface 110 side on the side of the platen 400. The cap member 500 can move up and down, and rises to seal the surface of the nozzle plate 260 when the carriage 200 stops at the home position close to the side surface portion 110. 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. Note that the inside of the cap member 500 is coupled to the pump unit 510. The pump unit 510 has a built-in pump motor 511 and can suck ink attached to the surface of the nozzle plate 260 through the cap member 500.

  In the embodiment shown in FIG. 3, an independent absorbing member 900 is provided for containing ink sucked by the cap member 500 and the pump unit 510. In other words, the waste liquid absorbent housed in the holding member 800 is provided below the absorbent member 420 on the platen 400 side. This waste liquid absorbing material is insulated from the surroundings by an insulating holding member 800. Furthermore, another waste liquid absorber 900 is disposed below the holding member 800. The waste liquid absorbent 900 can absorb and store the ink sucked from the cap member 500 by the pump unit 510 through the pipe 512.

  FIG. 4 is an exploded perspective view showing the structure of the platen 400 including the waste liquid absorbent 600 that can be used in the ink jet recording apparatus 11 shown in FIG. The same members as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in the figure, the platen 400 is formed by stacking a platen main body 401 containing the electrode 430 and the absorbing member 420 and a holding part 800 containing the waste liquid absorbent 600. Here, the holding portion 800 has an upper end complementary to the bottom surface of the platen main body 401 and can be integrated with the platen main body 401 in a state in which the waste liquid absorbent 600 is accommodated. Note that the holding portion 800 can be integrally formed of an injection molded resin.

  On the other hand, a depression 410 is formed on the upper surface of the platen main body 401, and several islands 412 are formed in the depression 410. In addition, ribs 418 are formed on the upper surfaces of the edge portions 402 and 404 that extend elongated before and after the depressed portion 410 and the top surface of the island portion 412. The ribs 418 are formed in parallel to each other along the recording material conveyance direction, and support the recording material from below at the tip thereof.

  In addition, a terminal portion insertion hole 416 for inserting a terminal portion 436 of an electrode member 430 described later is formed at the bottom end portion of the depressed portion 410. Similarly, a foot portion insertion hole 414 for inserting a foot portion 424 of the absorbing member 420 described later is formed in the vicinity of the island portion 412 on the bottom surface of the depressed portion 410. The platen main body 401 including the island portions 412, the ribs 418, the terminal portion insertion holes 416, and the foot portion insertion holes 414 can be integrally formed by injection molded resin.

  The electrode member 430 is a conductor plate having substantially the same shape as the bottom surface of the depressed portion 410 of the platen main body 401, an island portion insertion hole 432 for inserting the island portion 412 of the platen main body 401, and an absorption member 420 described later. A foot insertion notch 434 for inserting the foot 424; Further, a terminal portion 436 for coupling to a potential difference generating means 700 described later is formed at one end of the electrode member 430. The terminal portion 436 extends downward from the electrode member 430 itself. Therefore, when the electrode member 430 is accommodated in the depressed portion 410, the terminal portion 436 is exposed to the outside of the platen main body 401 through the terminal portion insertion hole 416.

  The electrode member 430 as described above is a metal that is corrosion resistant to the ink of the ink jet recording apparatus 11, such as gold, stainless steel or nickel wire, plate or foil, or wire or plate plated with these metals. Alternatively, a foil material, or a net-like or lattice-like member combining these materials can be used. As another aspect, the electrode member 430 can be formed of a conductive coating layer, a plating layer, a thick film layer, a thin film layer, or the like directly formed on the depressed portion of the platen main body 401.

  The platen main body 401 accommodates the absorbing member 420 so as to overlap the electrode member 430 inside the depressed portion 410. The absorbing member 420 also has substantially the same outer shape as the depressed portion 410. Further, the island part insertion hole 422 for inserting the island part 412 of the platen main body 401 is provided at a position corresponding to the arrangement of the island part 412.

  Further, the absorbing member 420 includes a foot portion 424 extending downward from the edge of each island portion insertion hole 422. The foot 424 is formed by shaping the absorbing member 420 itself and then bending it downward using a part of the portion that is unnecessary for forming the island insertion hole 422. The foot 424 extends through the platen body 401 through the foot insertion notch 434 of the electrode member 430 and the foot insertion hole 414 of the platen body 401, and the lower end thereof is shown in FIG. In contact with the waste liquid absorbent 600.

  The absorbing member 420 directly receives the droplets that have been ejected from the nozzle plate 260 and have not adhered to the recording material 300. At this time, if the absorption speed of the absorbing member 420 is low, a so-called milk crown is generated by the impact of droplets colliding with the surface of the absorbing member 420. Fine droplets form from the periphery of the milk crown, which also causes aerosol generation. Therefore, as the material of the absorbing member 420, a foam material having a high porosity is selected with an emphasis on the high absorption rate.

The absorbing member 420 is made of a conductive material having a surface resistance of 10 ⁸ Ω or less. Specifically, a conductive material such as polyethylene or polyurethane is mixed with a conductive material such as metal or carbon and then foamed, and a conductive material such as metal or carbon is attached to a foamed resin material such as polyethylene or polyurethane. Or plated ones can be used. In addition, a material obtained by impregnating an electrolyte solution into a resin foam material such as polyethylene or polyurethane can be used as the absorbing member 420.

  In the series of members shown in FIG. 4, the electrode member 430 is coupled to the nozzle plate 260 via the potential difference generating means 700 as schematically shown in the drawing. Therefore, an electric field of, for example, 25 kV / m or more is formed between the nozzle plate 260 and the electrode member 430. In the form shown in FIG. 4, the negative electrode side of potential difference generating means 700 is electrically connected to nozzle plate 260, and the positive electrode side of potential difference generating means 700 is electrically connected to electrode member 430. However, the connection between the positive and negative electrodes may be reversed.

  In addition, since the absorbing member 420 is in contact with the waste liquid absorbing material 600 at many feet 424, the ink absorbed by the absorbing member 420 is promptly guided to the waste liquid absorbing material 600 through each foot 424. Therefore, the amount of ink that adheres to the electrode member 430 disposed below the absorbing member 420 is small, and the deterioration of the electric field on the electrode member 430 side due to the adhesion of ink is small.

  Furthermore, the electrode member 430 covers the bottom of the depressed portion 410 of the platen main body 401 over substantially the entire surface, and the absorbing member 420 having substantially the same shape is accommodated thereon. As described above, since the entire lower surface of the absorbing member 420 is in contact with the electrode 430, even if there is a discontinuous portion in the internal structure of the absorbing member 420, the entire absorbing member 420 has a uniform potential substantially equal to that of the electrode member 430. .

  FIG. 5 is a cross-sectional view of the platen 400 shown in FIG. That is, FIG. 4 shows a cut surface cut by a vertical surface including the arrow A in FIG. 4 in a state where the platen 400 shown in an exploded state is assembled integrally.

  As shown in the figure, in a state where the platen 400 is assembled, the waste liquid absorbent 600 is sealed in a space defined by the platen main body 401 and the holding unit 800. This space communicates with the outside only through a foot insertion hole 414 formed in the bottom of the platen main body 401, and the foot 424 of the absorbing member 420 is inserted therethrough. The platen main body 401 and the holding portion 800 are both formed of an insulating material. Therefore, the ink absorbed in the waste liquid absorbing material 600 is not electrically coupled to a member outside the platen 400.

That is, in the ink jet recording apparatus 11, there are other parts having potentials different from those of the ink in the electrode 430, the absorbing member 420, and the waste liquid absorbing material 600 in addition to the nozzle plate 260. Typical examples include electric / electronic circuits such as the electric circuit 120, the head motor 246, the transport motor 320, and the pump motor 511. Further, many of these electric / electronic circuits are often grounded to the metal portion of the frame 100, and the electrical components around the recording head 210 are no exception. Furthermore, many metal members are used in the ink jet recording apparatus 11. As a typical example, metal parts may be used for the frame 100, the guide shaft 220, the conveyance roller 310, and the like. On the other hand, as already described, the ink absorbed in the waste liquid absorbent 600 has conductivity. However, in the ink jet recording apparatus 11 according to the present embodiment, the waste liquid absorber 600 is electrically sealed by the holding unit 800 that is an insulator. Thus, the waste liquid absorbent 600 is electrically insulated from surrounding members such as the pump motor 511, the frame 100, the head motor 246, the transport motor 320, and the electronic circuit 120. Therefore, an electrical short circuit between the waste liquid absorbent 600 and surrounding members is prevented.
Referring again to FIG. 3, the path of ink (waste liquid) from the cap member 500 to the cap-side waste liquid absorbent 900 is itself wetted by conductive ink. Therefore, when the carriage 200 is in the home position and the cap member 500 seals the nozzle plate 260, the ink (waste liquid) including the nozzle plate 260, the cap member 500, the pump unit 510, the pipe 512, and the waste liquid absorber 900. Are all at the same potential. On the other hand, the absorbing member 420 of the platen 400 and the waste liquid absorbing material accommodated in the holding unit 800 are also electrically coupled for the absorbed ink, and both are at the same potential.
On the other hand, in this embodiment, the waste liquid absorber on the absorption member 420 side is accommodated in the insulating holding member 800, and the waste liquid absorber 900 on the cap member 500 side is disposed outside the holding member 800. ing. Therefore, both are not electrically connected, and the nozzle plate 260 and the absorbing member 420 are not short-circuited via the cap member 500 side.

  FIG. 6 is a conceptual diagram showing the aerosol collecting mechanism 13 in the ink jet recording apparatus shown in FIGS. Also in FIG. 6, the same components as those shown in FIGS. 1 to 5 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in the figure, the nozzle plate 260 has a plurality of openings 262 for ejecting ink. Usually, a recording object 300 supported by the rib 418 of the platen main body 401 from below is directly below the nozzle plate 260. Accordingly, the droplet 268 ejected from the nozzle plate 260 adheres to the recording material 300.

  However, when ink is to be adhered to the edge of the recording object 300 without a margin, the recording object 300 exists directly below a part of the openings 262 at the side edge part 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 droplet 266 by discharging from the opening 262 is quickly lost due to the viscous resistance of the atmosphere, and some droplets are completely lost long before reaching the absorbing member 420. Is called. Further, since the mass of the droplet 266 is very small, the drop motion due to gravitational acceleration and the viscous resistance force are almost balanced, and the drop speed of the droplet 266 is extremely slow. Thus, aerosol floating below the nozzle plate 260 is generated.

  However, in the aerosol collecting mechanism 13 shown in FIG. 6, an electric field E is formed between the nozzle plate 260 and the absorbing member 420. That is, as already described with reference to FIG. 4, in this ink jet recording apparatus, 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 electrode member 430 via the terminal portion 436. , Each connected. Further, the electrode member 430 is in contact with the entire lower surface of the absorbing member 420 over the entire upper surface thereof. Further, the absorbing member 420 has conductivity. Therefore, the upper surface of the absorbing member 420 has substantially the same potential as the electrode 430, and the potential is uniform throughout.

  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 at the tip A of 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. Therefore, the droplet 266 having the electric charge q moves downward without being decelerated by obtaining kinetic energy from the electric field E by the Coulomb force Fe (qE), and finally can reach the absorbing member 420.

  Further, the absorbing member 420 communicates with the waste liquid absorbing material 600 through the foot portion 424. Accordingly, the ink absorbed by the absorbing member 420 is sequentially absorbed by the waste liquid absorbent 600. Here, the periphery of the waste liquid absorbent 600 is surrounded by a holding portion 800 that is an insulator. Therefore, the ink absorbed by the waste liquid absorbent 600 is not electrically coupled to other portions inside the ink jet recording apparatus 11.

  FIG. 7 is an exploded perspective view showing the structure of a platen 400A including the waste liquid absorbent 610 that can be used in the ink jet recording apparatus 11 shown in FIG. The same members as those shown in FIG. 6 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in the figure, in this embodiment, the platen main body 401 is omitted and the number of parts is reduced. However, an island portion 812 is formed at the bottom of the holding portion 810 in order to support the recording object 300 that the island portion 412 of the platen main body 401 was responsible for. In addition, ribs 818 that support the recording object 300 are formed on the edge portions 802 and 804 of the holding unit 810 that are front and rear in the conveyance direction of the recording object 300. Furthermore, an island portion insertion hole 612 is formed in the waste liquid absorbent 610 accommodated in the holding portion 810. Furthermore, a step 816 for supporting the electrode member 430 at a predetermined height is formed on the inner surface of the side wall of the holding portion 810. In addition, this holding | maintenance part 810 can be integrally formed with the resin which carried out the injection molding resin, combining the island part 812 and the rib 818. FIG.

  FIG. 8 is a cross-sectional view of the platen 400A shown in FIG. That is, FIG. 7 shows a cut surface cut by a vertical surface including the arrow A in FIG. 7 in a state where the members shown in an exploded state are assembled.

  As shown in the figure, in a state in which the platen 400A is assembled, the waste liquid absorber 610 is sealed in a space defined by the holding portion 810 and the electrode member 430. This space communicates with the outside only through the island insertion hole 432 formed in the electrode member 430, and the leg portion 424 of the absorbing member 420 is inserted into the island insertion hole 432. In addition, the holding portion 810 is formed of an insulating material, and at the same time, the surface of the electrode member 430 is covered with the absorbing member 420. Therefore, the ink absorbed in the waste liquid absorbing material 610 is not electrically coupled to other members in the ink jet recording apparatus 11.

  FIG. 9 is an exploded perspective view showing the structure of the platen 400B including the waste liquid absorbent 610 that can be used in the ink jet recording apparatus 11 shown in FIG. The same members as those shown in FIG. 6 are denoted by the same reference numerals, and redundant description is omitted.

  As shown in the figure, this embodiment is characterized in that a holding portion 820 having the same shape as the platen 400A shown in FIG. 7 is formed integrally with the lower case 20 of the ink jet recording apparatus 11. Such a structure not only reduces the number of parts, but also reduces the number of assembly steps. In addition, this holding | maintenance part 820 can integrally form with the resin which carried out injection molding resin combining the island part 822, the rib 828, and the lower case 20. FIG.

  10 is a cross-sectional view of the member shown in FIG. That is, a cut surface cut by a vertical surface including an arrow A in FIG. 9 in a state where the members shown in FIG.

  As shown in the figure, in a state where the platen 400B is assembled, the waste liquid absorbing material 610 is sealed in a space defined by the holding portion 820 and the electrode member 430. This space communicates with the outside only through the island insertion hole 432 formed in the electrode member 430, and the foot 424 of the absorbing member 420 is inserted therethrough. Further, the holding portion 820 is formed of an insulating material, and at the same time, the absorbing member 420 covers the surface of the electrode member 430. Therefore, the ink absorbed by the waste liquid absorbing material 610 is not electrically coupled to other members in the ink jet recording apparatus 11. Also, with this structure, the height from the lower surface of the lower case 20 to the top of the platen 400B can be suppressed, which contributes to the miniaturization of the ink jet recording apparatus 11.

  Thus, a constant voltage may be applied to the absorbing member side of the liquid ejecting apparatus for the purpose of forming an electric field for collecting aerosol. Further, the liquid absorbed by the waste liquid absorbing material itself has conductivity and is at the same potential as the absorbing member. On the other hand, there are many members having a potential different from that of the absorbing member inside the liquid ejecting apparatus. For this reason, when the liquid absorbed by the waste liquid absorbent material touches another member inside the ejection device, the potential of the absorbent member changes and the liquid recovery function by the electric field deteriorates. On the other hand, in the liquid ejecting apparatus according to the present invention, since the waste liquid absorbing material is accommodated in the holding portion formed of an insulator, the waste liquid does not touch other members in the liquid ejecting apparatus. Therefore, the potential of the absorbing member is stabilized, and the intended performance of collecting aerosol is stably maintained.

  As mentioned above, although demonstrated using embodiment of this invention, 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.

  Further, as a specific example of the liquid ejecting apparatus to which the present invention can be applied, for manufacturing an electrode forming apparatus or a biochip in manufacturing a color material ejecting apparatus, an organic EL display, an FED (surface emitting display), etc. Examples of the sample ejection head to be used are listed above, but the object of the present invention is not limited to these.

FIG. 2 is a perspective view of an overview of the entire liquid ejecting apparatus according to the invention. The perspective view which extracts and shows the internal mechanism 12 vicinity of the injection apparatus shown in FIG. The perspective view which shows other embodiment of the internal mechanism 12 of the injection apparatus shown in FIG. The disassembled perspective view which shows the structure of the platen which can be used with the injection apparatus shown in FIG. The longitudinal cross-sectional view shown in the state which assembled the platen shown in FIG. FIG. 2 is an enlarged side view showing the vicinity of a nozzle plate of the injection device shown in FIG. The perspective view which shows the other form of the platen which can be used with the injection apparatus shown in FIG. The longitudinal cross-sectional view shown in the state which assembled the platen shown in FIG. The perspective view which shows the further another form of the platen which can be used with the injection apparatus shown in FIG. The longitudinal cross-sectional view shown in the state which assembled the platen shown in FIG.

Explanation of symbols

10 hoppers, 11 inkjet recording devices, 12 internal mechanisms, 13 aerosol collection mechanisms, 20 lower cases, 22 upper cases, 30 discharge trays, 100 frames, 110, 111 side portions, 120 electrical circuits, 200 carriages, 210 recording heads, 220 Guide shaft, 242 and 244 Pulley, 230 Timing belt, 246 Head motor, 250 Ink cartridge, 260 Nozzle plate, 262 Opening, 264 Ink column, 266, 268 Droplet, 270 Multi-core cable, 300 Recorded object, 310 Conveyance Roller, 320 Conveyor motor, 400, 400A, 400B Platen, 401 Platen body, 402, 404 Edge, 410 Depressed part, 412, 812, 822 Island part, 414 Foot part insertion hole, 416 Terminal part insertion hole, 4 18 Rib, 818 Rib, 828 Rib, 420 Absorbing member, 422 Island part insertion hole, 424 Foot part, 430 Electrode member, 432 Island part insertion hole, 434 Foot part insertion notch, 436 Terminal part, 500 Cap member, 510 Pump unit, 511 Pump motor, 512 pipe, 520 Wiping means, 600 Waste liquid absorber, 700 Potential difference generating means, 800, 810, 820 Holding part, 816 Step, 826 Step, 900 Waste liquid absorber

Claims (7)

A liquid ejecting head having a conductive nozzle plate and discharging liquid from an opening of the nozzle plate to a recording material;
A guide portion for supporting the liquid jet head;
A conductive frame that supports the guide portion;
An absorbing member that is disposed opposite to the nozzle plate in the direction in which the liquid is discharged, absorbs the liquid that has not landed on the recording material, and has conductivity.
An electrode that has the same shape as the absorbing member and is overlaid with the absorbing member, touches the entire lower surface of the absorbing member, and is electrically connected to the absorbing member;
A potential difference generating means for generating a potential difference between the nozzle plate and the electrode to electrically attract the liquid to the electrode side;
A waste liquid absorber having a lower porosity than the absorbent member, and holding the liquid absorbed by the absorbent member by contacting at least part of the absorbent member;
A liquid ejecting apparatus including the waste liquid absorbing material and a holding unit having electrical insulation . A cap covering the nozzle plate of the liquid jet head;
A tube for conveying the liquid discharged to the cap;
A cap-side absorbent material that absorbs and holds the liquid conveyed by the tube;
The liquid ejecting apparatus according to claim 1, wherein the holding unit electrically insulates the waste liquid absorbent from the cap side absorbent. A pump for conveying the liquid in the tube;
A pump motor for driving the pump;
The liquid ejecting apparatus according to claim 2, wherein the holding unit electrically insulates the waste liquid absorbing material from the pump motor. A head motor for driving the liquid jet head along the guide portion;
The liquid ejecting apparatus according to claim 1 , wherein the holding unit electrically insulates the waste liquid absorbing material from the head motor. A transport unit for transporting the recording material;
A transport motor that drives the transport unit;
The liquid ejecting apparatus according to claim 1 , wherein the holding unit electrically insulates the waste liquid absorbing material from the transport motor. An electric circuit for controlling the liquid ejecting head;
The liquid ejecting apparatus according to claim 1 , wherein the holding unit electrically insulates the waste liquid absorbing material from the electric circuit. A platen disposed opposite to the nozzle plate in the liquid ejecting apparatus in a direction in which the liquid is discharged, and supporting a recording material;
An air-absorbing member that absorbs liquid, and an electrically conductive member;
An electrode that has the same shape as the absorbing member and is overlaid with the absorbing member, touches the entire lower surface of the absorbing member, and is electrically connected to the absorbing member;
A waste liquid absorber having a lower porosity than the absorbent member, and holding the liquid absorbed by the absorbent member by contacting at least part of the absorbent member;
A platen unit including the waste liquid absorbent and a holding part having electrical insulation .

Images