JP2007118319A - Liquid jetting apparatus, recorder and potential controlling unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent contamination caused by charging of a recording paper 170 from occurring. <P>SOLUTION: The liquid jetting apparatus is equipped with: a recording head 164 which has a conductive nozzle plate 166 and jets a liquid from an opening 168 of the nozzle plate 166 towards the recording paper 170 while reciprocating on the recording paper 170; a bottom electrode 310 disposed at the side of the object to be recorded farther than the recording paper 170 oppositely to the nozzle plate 166 for a direction in which the liquid is jetted; a potential difference generating means 330 which generates a potential difference between the nozzle plate 166 and the bottom electrode 310 thereby electrically attracting the liquid jetted from the opening 168 of the nozzle plate 166 towards the bottom electrode 310; and a rib electrode 156 which moves electric charges accumulated in the recording paper 170 thereby bringing the recording paper 170 and the nozzle plate 166 to the same potential. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid ejecting apparatus. More specifically, the present invention relates to a liquid ejecting apparatus and a recording apparatus for attaching a liquid ejected from an opening of a nozzle plate mounted on a liquid ejecting head to a recording material, and an electric field generating unit that can be used by being mounted on these apparatuses.

  In recent liquid ejecting apparatuses, droplets ejected from the opening of the nozzle plate are miniaturized to about several pl in accordance with a request for improving the resolution of a recorded image. 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 3 pl ejected from a nozzle plate has a velocity of substantially zero when it travels about 3 mm in the atmosphere. 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 fall completely.

  It is also conceivable to increase the jetting speed of the liquid in order to give a larger kinetic energy to the droplet. However, when the jetting speed from the nozzle plate is actually increased, very fine droplets called ink mist are likely to be generated when the droplets are detached from the nozzle plate. In addition, it has been found that, as the flying speed increases, the viscous resistance of the atmosphere acting on each droplet also increases, so that the reach distance of the droplet is rather shortened.

  Further, in the liquid ejecting apparatus, in the case where the liquid is adhered without leaving a margin at the peripheral portion of the recording material, an inevitable misalignment between the recording material and the liquid ejecting head is expected and the size of the recording material is exceeded. The liquid is jetted over a slightly wide area. For this reason, in the vicinity of both side edges and front and rear end portions of the recording material, the liquid may be discharged even to an area where the recording material does not exist. As for the surplus liquid droplets that do not adhere to the recording material in this manner, the surplus liquid is absorbed by disposing an absorbing member at a position facing the liquid ejecting head in the liquid ejection direction. However, the absorbing member is disposed farther than the recording material with respect to the nozzle plate. Therefore, in order for the liquid droplets to reach the absorbing member, it must fly a distance larger than the recording material. For this reason, many liquids that float without reaching the absorbing member are generated from the liquid ejected to the area where the recording object does not exist.

  The floating droplets generated as a result of various phenomena as described above are called aerosols and float around the moving area of the liquid ejecting head. Part of the aerosol floats to the outside of the liquid ejecting apparatus, adheres to the periphery of the liquid ejecting apparatus, and is contaminated. 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. Further, when the aerosol adheres to the electric circuit, the rotary scale, 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. Therefore, it has been proposed to prevent the generation of aerosol.

  Patent Document 1 listed below uses a metal nozzle plate as one electrode to form an electric field between the nozzle plate and an electrode disposed at a position facing the nozzle plate with the object to be processed interposed therebetween. ing. Since the droplets discharged from the nozzle plate are charged to the same polarity as the nozzle plate for the reasons described later, a Coulomb force acting toward the electrode acts in the electric field. Therefore, since it continues to fly to the electrode without being decelerated in the electric field, as a result, droplets floating as an aerosol can be reduced.

In this liquid ejecting apparatus, an absorbing member made of a porous material is disposed on the side opposite to the nozzle plate with respect to the object to be processed. Since this absorbing member has a liquid absorbing power by capillary action, it absorbs and holds the droplets that have come in without adhering to the object to be processed.
JP 2004-202867 A

  In the liquid ejecting apparatus described in Patent Document 1, the workpiece is not electrically connected anywhere and is in an electrically floating state. For this reason, when the droplets adhere to and accumulate on the object to be processed by the recording operation, the charges of the droplets are also accumulated on the object to be processed, and the object to be processed is further charged. Accordingly, when the amount of ink discharged in one-pass printing is large, the electric field strength between the nozzle plate and the recording material may exceed the electric field strength between the nozzle plate and the electrode.

  In such a case, electric lines of force extend from the object to be processed to the nozzle plate and the electrode, and charged droplets discharged from the nozzle plate and passing near the side of the object to be processed in the next pass become the electric force. It is captured by the wire and contaminates the side end face of the workpiece. Thus, it has been found that when an electric field is formed in the vicinity of the nozzle plate for the purpose of reducing floating aerosol, the recording material may be contaminated.

  In order to solve the above problems, as a first embodiment of the present invention, a conductive nozzle plate is provided, and liquid is ejected from the opening of the nozzle plate toward the recording material while reciprocating on the recording material. A potential difference is generated between the liquid ejecting head, the recording object side electrode disposed farther than the recording object facing the nozzle plate in the direction in which the liquid is ejected, and the nozzle plate and the recording object side electrode. The potential difference generating means for electrically attracting the liquid ejected from the opening of the nozzle plate toward the recording object side electrode and the charge accumulated in the recording object are moved to make the recording object and the nozzle plate have the same potential. There is provided a liquid ejecting apparatus including a potential control means. Thereby, the potential of the recording material is kept the same as that of the nozzle plate. Therefore, the aerosol charged to the same polarity as the nozzle plate is prevented from attracting the recording material, and it is difficult to adhere to the recording material, thereby reducing contamination.

  Further, in the liquid ejecting apparatus, the potential control means is provided on the platen that positions and supports the recording material from below at a position facing the liquid ejecting head, and is opposite to the surface on which the liquid of the recording material is ejected. The electrode member which contact | abuts the surface of this may be included. As a result, the electrode provided on the platen touches the recording material immediately below the nozzle plate to control the potential, so that the potential of the recording material can be controlled efficiently.

  Further, in the above liquid ejecting apparatus, the potential control means includes a conveyance driving roller that is rotationally driven while being in contact with the recording material so as to convey the recording material in a direction intersecting the reciprocating direction, and the recording material. It may include at least one of a transport driven roller rotated by the transport drive roller while sandwiching the. Thereby, the potential of the recording material can be controlled by using an existing member in the liquid ejecting apparatus. Further, the potential of the recording material is kept the same as that of the nozzle plate before the recording material reaches just below the nozzle plate. Therefore, contamination by aerosol at the front end of the recording material is prevented.

  Further, in the above liquid ejecting apparatus, the potential control means includes a discharge driving roller that is driven to rotate while being in contact with the recording material so as to discharge the recording material in a direction intersecting the reciprocating direction, and the recording material. It may include at least one of a discharge driven roller rotated by the discharge drive roller while sandwiching. Thereby, the potential of the recording material can be controlled by using an existing member in the liquid ejecting apparatus. Further, even after the recording material passes just below the nozzle plate, the potential of the recording material is maintained the same as that of the nozzle plate. Therefore, contamination by aerosol at the rear end of the recording material is effectively prevented.

  Further, in the liquid ejecting apparatus, the potential control means includes a conveyance driving roller that is driven to rotate while contacting the recording material so as to convey the recording material in a direction intersecting the reciprocating direction, and the recording material. At least one of a transport driven roller that is rotated by the transport drive roller while sandwiching the recording medium, a discharge drive roller that is rotationally driven while being in contact with the record to eject the record in a direction intersecting the reciprocating direction, and It may include at least one of a discharge driven roller that is rotated by the discharge drive roller while sandwiching the recording material together with the discharge drive roller. Thereby, the potential of the recording material can be controlled by using an existing member in the liquid ejecting apparatus. In addition, both before the leading edge of the recording material reaches directly below the nozzle plate and after the trailing edge of the recording material passes under the nozzle plate, the potential of the recording material is kept the same as that of the nozzle plate. The Therefore, contamination by aerosol at the rear end of the recording material is effectively prevented.

  Furthermore, in the liquid ejecting apparatus, the potential control means may include an electrode member having conductivity that comes into contact with the recording material. As a result, good electrical connection can be obtained at a desired position with respect to the recording material, so that it becomes easy to keep the potential of the recording material at the desired potential.

  As a second embodiment of the present invention, a recording head having a conductive nozzle plate and reciprocatingly moving on the recording material and discharging ink from the opening of the nozzle plate toward the recording material; A potential difference is generated between the recording object side electrode disposed farther than the recording object facing the nozzle plate in the direction of ejection, and the nozzle plate and the recording object side electrode, and from the opening of the nozzle plate Potential control for electrically drawing the ejected ink toward the recording material side electrode and the recording material and the potential difference generating device are electrically coupled to make the recording material the same potential as the nozzle plate. And a recording apparatus comprising the means. Thereby, the effect similar to the 1st form can be acquired.

  Furthermore, as a third embodiment of the present invention, the liquid ejecting apparatus is equipped with a liquid ejecting head that ejects liquid from the opening of the conductive nozzle plate toward the recording material while reciprocating on the recording material. A potential control unit, which is a potential difference between a recording object-side electrode disposed opposite to a recording object and facing the nozzle plate in a direction in which liquid is ejected, and the nozzle plate and the recording object-side electrode. And a potential difference generating means for electrically attracting the liquid ejected from the opening of the nozzle plate toward the recording material side electrode, and moving the charge accumulated in the recording material to move the recording material and the nozzle plate. There is provided a potential control unit comprising a potential control means for setting the same potential. Thereby, the effect similar to the 1st form can be acquired.

  The summary of the invention does not enumerate all necessary features of the present invention. Further, a sub-combination of these feature groups can be an 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. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a perspective view showing an overview of an ink jet recording apparatus 10 according to one embodiment of the present invention. In this embodiment, an upper case 110 as a cover is opened. As shown in FIG. 1, the ink jet recording apparatus 10 includes a lower case 120 serving as a base of the apparatus, an upper case 110 that forms a casing together with the lower case 120, and a paper support attached to the rear portion of the lower case 120. 130 and a discharge tray 140 formed on the front surface of the lower case 120. Further, the ink jet recording apparatus 10 includes a platen 150 disposed horizontally in the lower case 120 and a carriage 160 disposed above the platen 150 inside the casing. In FIG. 1, the paper support 130 is loaded with a recording sheet 170 as a recording object.

  In the ink jet recording apparatus 10 as described above, the recording paper 170 accommodated in the paper support 130 is taken into the inside one by one by a feeding unit (not shown), and then the platen by a transport unit (not shown). 150 is sent out. Further, the paper is sent to the discharge tray 140 by a discharge unit (not shown). In each of the feeding unit, the conveyance unit, and the discharge unit, the recording paper 170 is fed, conveyed, or discharged by being sandwiched between a driving roller that is rotationally driven and a driven roller that is driven by the driving roller.

  In the ink jet recording apparatus 10, the carriage 160 reciprocates in a direction perpendicular to the conveyance direction of the recording paper 170 above the platen 150. Therefore, the entire upper surface of the recording paper 170 can be scanned by the carriage 160 by alternately conveying the recording paper 170 and reciprocating the carriage 160. Thereby, the carriage 160 can perform a recording operation in an arbitrary area on the upper surface of the recording paper 170.

  FIG. 2 is a perspective view showing the internal mechanism 20 of the ink jet recording apparatus 10 shown in FIG. 1 with the frame 210 including the side portions 212 and 214 extracted. As shown in the figure, the internal mechanism 20 is composed of a frame 210 disposed substantially vertically rearward and a pair of side surface portions 212 and 214 extending from both side end portions in parallel toward the front. It is mainly formed inside the area to be defined.

  As shown in the figure, in the internal mechanism 20, the carriage 160 is supported by a guide shaft 220 that passes through the carriage 160. The end of the guide shaft 220 is supported by the side portions 212 and 214, and is arranged in parallel to the frame 210 and horizontally. Accordingly, the carriage 160 can move horizontally along the guide shaft 220.

  Behind the carriage 160, a pair of pulleys 232 and 234 and a timing belt 230 hung on the pulleys 232 and 234 are disposed on the front surface of the frame 210. One pulley 234 is rotationally driven by a carriage motor 236. The timing belt 230 is coupled to the rear portion of the carriage 160. Accordingly, the carriage 160 can be reciprocated according to the operation of the carriage motor 236.

  The carriage 160 is loaded with an ink cartridge 162 from above, and includes a recording head 164 on the lower surface thereof. Further, the recording head 164 includes a metal nozzle plate 166 including an opening for ejecting ink on the lower surface thereof. Therefore, ink is ejected downward from the carriage 160. Further, the carriage 160 is coupled to an electronic circuit 250 behind the frame 210 via a tape-shaped multicore cable 240. Since the multi-core cable 240 flexes flexibly as the carriage 160 moves, it does not hinder the reciprocating movement of the carriage 160.

  A platen 150 is disposed below the area where the carriage 160 reciprocates. The platen 150 supports the recording paper 170 passing under the carriage 160 from below, and keeps the distance between the nozzle plate 166 and the recording paper 170 constant. A depression 152 is formed on the upper surface of the platen 150, and the absorbing member 260 is accommodated in the depression 152. The absorbing member 260 receives ink ejected from the recording head 164 toward the area where the recording paper 170 does not exist.

  Note that ink adheres to the absorbing member 260 as the operation time of the ink jet recording apparatus 10 elapses. When the recording paper 170 comes into contact with the absorbing member 260 to which ink has adhered, the back surface of the recording paper 170 is contaminated with ink. Therefore, by forming a rib-shaped portion on the upper surface of the platen 150 and lifting and supporting the recording paper 170 from below, contact between the two is maintained to prevent contact. Specifically, a gap of about 2 to 4 mm is provided between the recording paper 170 and the absorbing member 260. An interval of about 1 mm is also maintained between the surface of the nozzle plate 166 and the surface of the recording paper 170.

  The material of the absorbing member 260 is selected with emphasis on the liquid absorption speed on the surface. For this reason, its own absorption capacity is limited. Therefore, a waste liquid absorbing member 262 having a larger absorption capacity is disposed below the platen 150, and this part and the absorbing member 260 are in contact with each other. The waste liquid absorbing member 262 is made of a material having a large absorption capacity due to capillary action as well as its absorption capacity, and can absorb a large amount of ink from the absorbing member 260.

  On the other hand, a conveyance driving roller 282 and a conveyance driven roller 284 are disposed behind the platen 150 to form a conveyance unit 280. The transport driving roller 282 is rotationally driven by a transport motor 286 disposed behind the frame 210. Further, the conveyance driven roller 284 presses the recording paper 170 against the conveyance driving roller 282. Accordingly, the conveyance driven roller 284 is rotated along with the rotation of the conveyance driving roller 282 and the recording paper 170 is sent out onto the platen 150. Since ink is ejected from the carriage 160 on the platen 150 as described above, an image can be recorded on the recording paper 170 with ink.

  In addition, a discharge driving roller 292 and a discharge driven roller 294 are disposed in front of the platen 150 to form a discharge unit 290. The discharge drive roller 292 is rotationally driven by the power distributed from the transport motor 286 described above. Further, the discharge driven roller 294 presses the recording paper 170 that has passed through the platen 150 against the discharge driving roller 292. Accordingly, as the discharge driving roller 292 rotates, the discharge driven roller 294 is rotated and the recording paper 170 is sent out from the platen 150 to the outside.

  Further, in the internal mechanism 20, a cap member 270 is disposed on the side of the platen 150 on the side surface 212 side. The cap member 270 can move up and down, and rises when the carriage 160 stops at the home position close to the side surface portion 212 to seal the lower surface of the nozzle plate 166. Further, the inside of the cap member 270 is coupled to the pump unit 272. The pump unit 272 can suck ink adhering to the surface of the nozzle plate 166. The ink sucked by the pump unit 272 is absorbed by the waste liquid absorbing member 262 through a pipe (not shown).

  Further, wiping means 274 is disposed between the platen 150 and the cap member 270. When the carriage 160 released from the sealing by the cap member 270 passes above, the wiping means 274 wipes and cleans the lower surface of the nozzle plate 166.

  FIG. 3 is a cross-sectional view schematically showing the structure of the aerosol collecting mechanism 31 formed in the ink jet recording apparatus 10 as described above. As shown in the figure, the platen 150 includes a rib portion 154 that protrudes upward, and the recording paper 170 is positioned in the vertical direction by supporting the upper end of the rib portion 154 from below. Further, a metal rib electrode 156 is attached to the upper end of the rib portion 154. The rib electrode 156 is electrically connected to the negative electrode of the potential difference generating unit 330 and is in contact with the lower surface of the recording paper 170. Therefore, when the potential difference generating unit 330 operates, the recording paper 170 has the same potential as the negative electrode of the potential difference generating unit 330.

  Further, since the nozzle plate 166 is also connected to the negative electrode of the potential difference generating unit 330, as a result, the recording paper 170 and the nozzle plate 166 have the same potential, and the potential is the same as that of the negative electrode of the potential difference generating unit 330. Potential. As described above, in the aerosol collecting mechanism 31, the rib electrode 156 electrically connected to the potential difference generating unit 330 forms a part of the potential control unit of the recording paper 170.

  On the other hand, as described above, the absorbing member 260 is accommodated in the depressed portion 152 of the platen 150, and the bottom electrode 310 is further inserted between the lower surface of the absorbing member 260 and the bottom surface of the depressed portion 152. ing. The bottom electrode 310 is connected to the positive electrode of the potential difference generating unit 330 via a short circuit protection resistor 320. Therefore, when the potential difference generating means 330 operates, an electric field E corresponding to the potential difference generated by the potential difference generating means 330 is formed between the nozzle plate 166 and the bottom electrode 310. The platen 150 and its rib portion 154 are members formed of an insulating resin. Therefore, the bottom electrode 310 and the rib electrode 156 are prevented from short-circuiting each other.

  In the aerosol collecting mechanism 31, the bottom electrode 310 is made of a metal that is corrosion resistant to the ink of the ink jet recording apparatus 10, such as a gold, stainless steel, or nickel wire, a plate or foil, or a wire plated with these metals. , A plate material or a foil material, or a net-like or lattice-like member combining these materials. As another embodiment, the bottom electrode 310 can be formed of a conductive coating layer, a plating layer, a thick film layer, a thin film layer, or the like formed directly on the depressed portion 152 of the platen 150.

  The rib electrode 156 can be formed of a metal having high wear resistance such as stainless steel, nickel-plated iron, duralumin, iron containing chromium or molybdenum, tungsten, titanium, an alloy containing titanium, or the like and having high conductivity. Moreover, it can also form integrally with the platen 150 by embedding, sticking, or two-body molding using materials, such as carbon, a metal, and a conductive polymer. Further, an amorphous semiconductor such as selenium or silicon or a metal can be formed by partial vapor deposition on the rib portion 154.

Further, the absorbing member 260 is preferably formed of a conductive material having a surface resistance of 10 ⁸ Ω or less. Specifically, a conductive material such as polyethylene or polyurethane mixed with a conductive material such as metal or carbon and then foamed, or a conductive foam material such as polyethylene or polyurethane is adhered to a conductive material such as metal or carbon. A plated or plated one 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 260.

  The absorbing member 260 directly receives ink that has been ejected from the nozzle plate 166 and has not adhered to the recording paper 170. At this time, if the absorption speed of the absorbing member 260 is slow, the ink generates a so-called milk crown by an impact that collides with the surface of the absorbing member 260. Since fine ink droplets are generated from the periphery of the milk crown, which also causes aerosol generation, it is advantageous that the absorbing member 260 has a high absorption rate, in other words, a high porosity.

  Although not shown, the absorbing member 260 partially communicates with the waste liquid absorbing member 262 disposed below the platen 150 in FIG. For this reason, since the ink absorbed by the absorbing member 260 is sequentially absorbed by the waste liquid absorbing member 262 having higher absorbing power, the absorbing power of the absorbing member 260 is maintained for a long period of time.

  FIG. 4 is a schematic diagram for explaining the operation of the aerosol collecting mechanism 31. As shown in the drawing, the nozzle plate 166 has a plurality of openings 168 for ejecting ink. Further, as indicated by an arrow X in the drawing, the nozzle plate 166 moves from right to left in the drawing as the carriage 160 moves.

  When the recording paper 170 exists immediately below the nozzle plate 166, the ink droplets 344 ejected from the openings 168 of the nozzle plate 166 adhere to the recording paper 170. However, when ink is to be adhered to the edge of the recording paper 170 without a margin, the recording paper 170 does not exist directly below some of the openings 168 at the side edge and the front and rear ends of the recording paper 170. Sometimes.

  In such a case, the kinetic energy given to the ink droplet 342 by discharging from the opening 168 is rapidly lost due to the viscous resistance of the atmosphere, and in some ink droplets 342, the kinetic energy is completely dissipated long before reaching the absorbing member 260. To be lost. In addition, since the mass of the ink droplet 342 is very small, the drop motion due to gravitational acceleration and the viscous resistance force are almost balanced, and the drop velocity of the ink droplet 342 becomes extremely slow. Thus, the ink droplet 342 floating below the nozzle plate 166 becomes an aerosol.

  Incidentally, the ink pushed out from the opening 168 of the nozzle plate 166 becomes an ink column 340 that hangs down from the nozzle plate 166 at the moment immediately before the ink droplet 342 is formed. At this time, electric charges are accumulated between the tip A of the ink column 340 and the region B near the ink column 340 on the lower surface of the nozzle plate 166 by a so-called lightning rod effect.

  That is, the lightning rod effect referred to here is a region B on the surface of the nozzle plate 166 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 340 as an apex. It contributes to the charging of 342. Due to the lightning rod effect, the ink droplet 342 has a charge q that is larger than the charge corresponding to the horizontal cross-sectional area of the ink column 340 and has the same polarity as the nozzle plate 166.

  On the other hand, in the aerosol collecting mechanism 31, an electric field E is formed between the nozzle plate 166, the bottom electrode 310, and the absorbing member 260. As described above, since the ink droplet 342 is charged with the electric charge q, kinetic energy is obtained from the electric field E due to the Coulomb force F (qE), moves downward without being decelerated, and finally reaches the absorbing member 260. To reach.

  Further, in the aerosol collecting mechanism 31, the recording paper 170 is maintained at the same potential as the negative electrode of the potential difference generating unit 330 via the rib electrode 156. Accordingly, the electric charge of the ink droplet 344 that has landed on the recording paper 170 is discharged from the potential difference generating unit 300. Therefore, ink droplets 342 floating in the vicinity of the recording paper 170 can be prevented from attracting the recording paper 170. Therefore, the side end surface of the recording paper 170 is prevented from being contaminated by the aerosol.

  In the above embodiment, the bottom electrode 310 is connected to the positive electrode side of the potential difference generating unit 330, and the nozzle plate 166 and the recording paper 170 are connected to the negative electrode side of the potential difference generating unit 330. However, the same function can be realized even if all the polarities are reversed and connected. Further, the wiring in the aerosol collecting mechanism 31 can be simplified by setting one potential of the potential difference generated by the potential difference generating means 330 to the ground potential.

In order to prevent aerosolization by applying Coulomb force to ink droplets in the ink jet recording apparatus 10 as shown in FIGS. 1 to 4, the electric field intensity of the electric field E should be about 100 kV / m. desirable. In addition, when a potential difference nozzle plate to form such a field as one of the electrodes, charge stored in the liquid droplets ejected from the nozzle plate 166 is about 4 × 10 ^{-14 Q.}

On the other hand, when the recording paper 170 is ordinary fine paper or coated with porous silica or the like, its volume resistivity is about 10 ⁷ to 10 ¹³ Ωcm. When conductive ink permeates such a recording paper 170, its volume resistivity decreases to 10 ⁵ to 10 ⁷ Ωcm. Further, the surface resistivity of the recording paper 170 to which the ink is attached is about 10 ³ to 10 ⁷ Ω / □.

  Therefore, when the rib electrode 156 formed of a metal having sufficiently high conductivity is brought into contact with the recording paper 170 and connected to the potential difference generating unit 330, the recording paper 170 itself and the ink on the recording paper 170 are used to perform recording. Control can be made so that the potential of the sheet 170 matches the output voltage of the potential difference generating means 330. Further, even when charged ink droplets are accumulated on the recording paper 170, the electric charge of the ink droplets is discharged through the recording paper 170 itself and the ink attached thereto, so that the potential of the recording paper 170 does not fluctuate. .

  FIG. 5 is a cross-sectional view schematically showing the structure of the aerosol collecting mechanism 32 according to another embodiment. In FIG. 5, the same components as those in the other drawings are denoted by the same reference numerals, and redundant description is omitted.

  As shown in the figure, the structure of the aerosol collecting mechanism 32 according to this embodiment has a characteristic characteristic of the shape of the rib electrode 156. That is, the rib electrode 156 penetrates the rib portion 154 of the platen 150 up and down, and the lower end of the rib electrode 156 is exposed on the lower surface of the platen 150. Therefore, the wiring between the rib electrode 156 and the potential difference generating means 330 can be coupled at the lower part of the platen 150. According to such a structure, the functions as the rib electrode 156 and the aerosol collecting mechanism 32 are the same as those of the aerosol collecting mechanism 31 shown in FIG. high.

  FIG. 6 is a cross-sectional view schematically showing the structure of an aerosol collection mechanism 33 according to another embodiment. Also in FIG. 6, the same reference numerals are given to the same constituent elements as those in the other drawings, and redundant description will be omitted.

  As shown in the figure, in order to eject ink from the recording head 164 and attach it to the recording paper 170, the recording paper 170 must be fed onto the platen 150. Further, the recording paper 170 on which ink is adhered on the platen 150 must be sent out from the platen 150 to the outside. Such conveyance and discharge of the recording paper 170 are performed by a conveyance unit 280 and a discharge unit 290 each including a pair of rollers.

  The conveyance unit 280 includes a conveyance driving roller 282 that contacts the lower surface of the recording paper 170 and a conveyance driven roller 284 that contacts the upper surface of the recording paper 170 and presses the conveyance driving roller 282. Here, the transport driving roller 282 is rotationally driven by the transport motor 286. On the other hand, the conveyance driven roller 284 does not have a driving force itself, and is rotated by the rotation of the conveyance driving roller 282 while pressing the recording paper 170 against the conveyance driving roller 282. The transport driving roller 282 and the transport driven roller 284 continue to touch the recording paper 170 until the rear end passes after the front end of the recording paper 170 reaches. Therefore, the potential of the recording paper 170 can be controlled via the transport unit 280 by forming the transport drive roller 282 from a conductive material and simultaneously connecting it to the potential difference generating means 330.

  In addition, the discharge unit 290 includes a discharge drive roller 292 that contacts the lower surface of the recording paper 170 and a discharge driven roller 294 that contacts the upper surface of the recording paper 170 and presses against the discharge drive roller 292. Here, the discharge drive roller 292 is rotationally driven by the transport motor 286 via a transmission mechanism (not shown). On the other hand, the discharge driven roller 294 itself has no driving force, and is rotated by the rotation of the discharge drive roller 292 while pressing the recording paper 170 against the discharge drive roller 292. The discharge driving roller 292 and the discharge driven roller 294 continue to touch the recording paper 170 until the rear end passes after the front end of the recording paper 170 arrives. Therefore, the potential of the recording paper 170 can be controlled via the discharge unit 290 by forming the discharge drive roller 292 from a conductive material and connecting it to the potential difference generating unit 330.

  Further, both the discharge driving roller 292 and the discharge driven roller 294 are formed of a conductive material, and both are electrically connected to the potential difference generating unit 330, so that the leading edge of the recording paper 170 approaches the platen 150. Thus, the potential of the recording paper 170 can be continuously controlled until the trailing edge passes over the platen 150. Therefore, the aerosol that is discharged from the nozzle plate 166 and floats above the platen 150 jumps toward the bottom electrode 310 and is absorbed by the absorbing member 260 without being adsorbed by the recording paper 170.

  Examples of the material of the transport driving roller 282 and the discharge driving roller 292 include metal materials having rigidity and conductivity such as iron, nickel-plated iron, and stainless steel. Further, in the case of the conveyance drive roller 282, it is also preferable to improve the frictional force of the surface by attaching alumina particles or the like to the surface for the purpose of preventing the recording paper 170 from sliding. Further, instead of attaching alumina particles, the surface may be covered with conductive rubber or the like.

  FIG. 7 is a cross-sectional view schematically showing the structure of an aerosol collecting mechanism 34 according to another embodiment. Also in FIG. 7, the same reference numerals are given to the same constituent elements as those in the other drawings, and redundant description is omitted.

  As shown in the figure, in this embodiment, the conveyance driven roller 284 and the discharge driven roller 294 are electrically connected to the potential difference generating unit 330 in each of the conveyance unit 280 and the discharge unit 290. The function thus obtained is the same as that shown in FIG. 6, but this embodiment has the following advantages. That is, the transport drive roller 282 and the discharge drive roller 292 are both mechanically coupled to a rotation transmission mechanism such as a gear group for rotationally driving. Therefore, the mechanical contact in these transmission mechanisms can be used to electrically connect to the potential difference generating means 330. To that end, if the rotation transmission mechanism is entirely formed of a conductive material value. Don't be. However, this type of rotation transmission mechanism is often formed by a gear formed of a resin material, and replacing this with a metal material leads to an increase in manufacturing cost, an increase in operating noise, and the like.

  In this respect, since the conveyance driven roller 284 and the discharge driven roller 294 are only supported so as to be rotatable, they are formed of a conductive material and the shaft support means is electrically connected to the potential difference generation means 330. Can easily form the potential difference control means. In addition, as a material of the conveyance driven roller 284 and the discharge driven roller 294, a conductive metal such as iron, nickel-plated iron, and stainless steel, or a conductive resin material including carbon or metal powder is used. Can do.

  FIG. 8 is a cross-sectional view schematically showing the structure of an aerosol collecting mechanism 35 according to still another embodiment. Also in FIG. 8, the same reference numerals are given to the same constituent elements as those in the other drawings, and redundant description is omitted.

  As shown in the drawing, in this embodiment, in each of the transport unit 280 and the discharge unit 290, all of the transport drive roller 282, the transport driven roller 284, the discharge drive roller 292, and the discharge driven roller 294 are potential difference generating means. 330 is electrically connected. The functions thus obtained are the same as those shown in FIGS. 6 and 7, but this embodiment has the following advantages. That is, each roller is in contact with the recording paper 170, but when the recording paper 170 is actually conveyed or discharged, the contact and separation are repeated microscopically. For this reason, when focusing on a single roller, the electrical connection when the recording paper 170 is not stable. However, by increasing the number of rollers in contact with the recording paper 170, since any roller is in contact with the recording paper 170 as a whole, the potential of the recording paper 170 can be stabilized.

  FIG. 9 is a cross-sectional view schematically showing the structure of an aerosol collection mechanism 36 according to another embodiment. Also in FIG. 9, the same reference numerals are assigned to the same components as those in the other drawings, and duplicate descriptions are omitted.

  In the embodiment shown in the figure, a plurality of conductive brushes 350 are mounted as means for obtaining electrical connection to the recording paper 170. The conductive brush 350 is formed of a member having both conductivity and elasticity, and one end thereof is electrically connected to the potential difference generating unit 330. The other end of the conductive brush 350 is in contact with the recording paper 170 at a plurality of locations. That is, in the conveyance direction of the recording paper 170, immediately before the platen 150, the conductive brush 350 is disposed on the front surface and the back surface of the recording paper 170, and is in contact with the front surface and the back surface of the recording paper 170, respectively. Further, immediately after the platen 150, a conductive brush 350 is disposed on the back side of the recording paper 170 and is in contact with the back side of the recording paper 170.

  In such a form, a dedicated member called the conductive brush 350 must be introduced. However, since the conductive brush 350 is a dedicated part for obtaining an electrical connection, the arrangement can be freely selected. Therefore, the platen 150 and the nozzle plate 166 that are involved in aerosol collection can be disposed in the immediate vicinity, and the potential of the recording paper 170 can be controlled efficiently. In addition, the conductive brush 350 is listened to by a resin wire containing carbon or metal powder in addition to a metal wire such as stainless steel.

  As described in detail above, this liquid ejecting apparatus can actively collect ink mist charged with the same polarity as the nozzle plate to reduce the generation of aerosol, and at the same time, recording paper caused by charging of the recording material The contamination of 170 can also be suppressed. Further, the same function can be realized in the existing liquid ejecting apparatus by combining the potential difference generating means and the wiring connecting the potential difference generating means to the nozzle plate and the recording medium as a potential control unit.

  In the above embodiment, the specific configuration has been described by taking the ink jet recording apparatus 10 as an example. However, the liquid ejecting apparatus may be, for example, a color material ejecting apparatus or an organic EL display in the manufacture of a color filter for a liquid crystal display. In addition, it can be implemented as an electrode forming device in the manufacture of FED (surface emitting display), a sample ejecting head used for biochip manufacturing, a sample ejecting head as a precision pipette, a device for drawing pictures, characters, etc. However, it is not limited to these.

  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. In addition, 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.

1 is a perspective view showing an overview of an inkjet recording apparatus 10 as a whole. FIG. 3 is a perspective view showing an internal mechanism 20 extracted from the ink jet recording apparatus 10. Sectional drawing which shows the structure of the aerosol collection mechanism 31 which concerns on one embodiment. The schematic diagram explaining operation | movement of the aerosol collection mechanism 31. FIG. Sectional drawing which shows the structure of the aerosol collection mechanism 32 which concerns on other embodiment. FIG. 6 is a cross-sectional view showing the structure of another aerosol collecting mechanism 33. Furthermore, sectional drawing which shows the structure of the other aerosol collection mechanism 34. FIG. Furthermore, sectional drawing which shows the structure of the other aerosol collection mechanism 35. FIG. Furthermore, sectional drawing which shows the structure of the other aerosol collection mechanism 36. FIG.

Explanation of symbols

10 Inkjet recording device, 20 internal mechanism, 31, 32, 33, 34, 35, 36 aerosol collection mechanism, 110 upper case, 120 lower case, 130 paper support, 140 discharge tray, 150 platen, 152 concavity, 154 rib Part, 156 rib electrode, 160 carriage, 162 ink cartridge, 164 recording head, 166 nozzle plate, 170 recording paper, 210 frame, 212, 214 side surface part, 220 guide shaft, 230 timing belt, 232, 234 pulley, 236 carriage motor , 240 Multi-core cable, 250 Electronic circuit, 260 Absorbing member, 262 Waste liquid absorbing member, 270 Cap member, 272 Pump unit, 274 Wiping means, 280 Conveying unit, 282 Conveying drive roller 284 transport driven roller, 286 conveying motor, 290 discharge unit, 292 discharge driving roller, 294 follower roller, 310 a bottom electrode, 320 short-circuit protection resistor, 330 potential difference generating means, 340 ink column, 342, 344 ink droplets, 350 conductive brush

Claims (8)

A liquid ejecting head that has a conductive nozzle plate and ejects liquid from the opening of the nozzle plate toward the recording material while reciprocating on the recording material;
A recording-object-side electrode disposed opposite to the recording object in opposition to the nozzle plate in a direction in which the liquid is ejected;
A potential difference generating means for generating a potential difference between the nozzle plate and the recording object side electrode and electrically attracting the liquid ejected from the opening of the nozzle plate toward the recording object side electrode;
A liquid ejecting apparatus comprising: potential control means for moving the charge accumulated in the recording material to make the recording material and the nozzle plate have the same potential.   The potential control means is provided on a platen that supports and positions the recording material from below at a position facing the liquid ejecting head, and is disposed on a surface opposite to the surface on which the liquid is ejected. The liquid ejecting apparatus according to claim 1, comprising an abutting electrode member.   The potential control means sandwiches the recording object together with a conveyance driving roller that is rotationally driven in contact with the recording object so as to convey the recording object in a direction crossing the reciprocation direction, and the conveyance driving roller. The liquid ejecting apparatus according to claim 1, further comprising at least one of a transport driven roller rotated by the transport driving roller.   The potential control means sandwiches the recording material together with a discharge driving roller that is rotationally driven in contact with the recording material to discharge the recording material in a direction intersecting the reciprocating direction, and the discharge driving roller. The liquid ejecting apparatus according to claim 1, further comprising at least one of a discharge driven roller rotated by the discharge driving roller.   The potential control means sandwiches the recording object together with a conveyance driving roller that is rotationally driven in contact with the recording object so as to convey the recording object in a direction crossing the reciprocation direction, and the conveyance driving roller. And at least one of the transport driven rollers rotated by the transport drive roller, and a discharge drive that is rotationally driven in contact with the record to eject the record in a direction crossing the reciprocating direction. The liquid ejecting apparatus according to claim 1, further comprising at least one of a discharge driven roller that is rotated by the discharge drive roller while sandwiching the recording material together with the roller and the discharge drive roller.   The liquid ejecting apparatus according to claim 1, wherein the potential control unit includes a conductive electrode member that contacts the recording material. A recording head having a conductive nozzle plate, and ejecting ink from the opening of the nozzle plate toward the recording material while reciprocating on the recording material;
A recording-object-side electrode disposed opposite to the recording object in opposition to the nozzle plate in a direction in which the ink is ejected;
A potential difference generating means for generating a potential difference between the nozzle plate and the recording object side electrode and electrically attracting the ink discharged from the opening of the nozzle plate toward the recording object side electrode;
A recording apparatus comprising: a potential control unit that electrically couples the recording medium and the potential difference generating unit to bring the recording medium to the same potential as the nozzle plate. A potential control unit attached to a liquid ejecting apparatus including a liquid ejecting head that ejects liquid from an opening of a conductive nozzle plate while reciprocating on a recorded object toward the recorded object,
A recording-object-side electrode disposed opposite to the recording object in opposition to the nozzle plate in a direction in which the liquid is ejected;
A potential difference generating means for generating a potential difference between the nozzle plate and the recording object side electrode and electrically attracting the liquid ejected from the opening of the nozzle plate toward the recording object side electrode;
A potential control unit comprising: potential control means for moving the charge accumulated in the recording material to make the recording material and the nozzle plate have the same potential.

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