JP3706191B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus that forms an image by applying electrostatic force to ink in which colorant particles are dispersed in an insulating liquid carrier and causing ink droplets to fly onto a recording medium.
[0002]
[Prior art]
In recent years, ink jet printers using an ink jet recording method have been widely used in the personal printer field. However, since conventional ink jet printers use dye-based ink, there are problems such as poor image storage stability and light resistance.
[0003]
On the other hand, as a recording method that enables the use of pigment particles as a colorant, Japanese Patent Laid-Open No. 62-5282 has already proposed a basis for solving this problem. This guides a recording liquid in which electrified particles (toner) are dispersed in an insulating solvent to the opening where the electrodes are arranged, and also places an electric field between the recording medium and the opening close to the opposing recording medium. By forming, an image is formed by separating and discharging only charged particles from the recording liquid. This is a highly useful technology that enables non-contact recording by separating and discharging solid particles from a liquid.
[0004]
In addition, an image forming apparatus that enables the use of pigment particles as a colorant and solves the above-described problems of dye inks is disclosed in WO 93/11866. This apparatus includes a conductive ink supply tube, and a voltage is applied between the ink supply tube and a counter electrode facing the tip. Then, ink containing pigment particles (hereinafter referred to as charged toner) charged to the same polarity as the potential of the ink supply tube is supplied to the ink supply tube.
[0005]
The charged toner in the ink receives an electrostatic attraction force from the counter electrode at an ejection point near the tip of the ink supply tube to form a semi-spherical ink meniscus. However, the toner cannot fly from the ink meniscus due to the surface tension of the solvent of the ink, and remains at the tip of the ink meniscus. In this way, a large amount of toner collects at the tip of the ink meniscus and becomes an aggregate. When the voltage between the ink supply tube and the counter electrode is further increased, the electrostatic attraction force exceeds the surface tension of the ink solvent, and toner aggregates fly from the ink meniscus.
[0006]
In the image forming apparatus based on the above-described flying principle, pigment particles can be used because there is no nozzle for determining the flying droplet size as in conventional ink jet recording. For this reason, problems such as image storability and light resistance, which are problems of the conventional ink jet printer, are solved.
[0007]
[Problems to be solved by the invention]
However, many problems remain in these devices and technologies. First, Japanese Patent Laid-Open No. 62-5282 does not disclose specific means such as a means for forming a meniscus in an opening corresponding to each recording pixel and a means for sending an electric signal. It is insufficient for use as a technology.
[0008]
Further, in the image forming technique according to WO 93/11866, a triangular electrode is used as a discharge point, so that the electric field at the tip is the strongest. For this reason, the toner, which is the charged particles supplied, has the same polarity as the bias voltage applied to the electrodes, so it cannot receive the tip that is the discharge point due to the repulsive force, or even very slowly if possible. Therefore, the recording is interrupted, or the recording dots (pixels) are suddenly reduced. For this reason, the recording frequency is also extremely unstable.
[0009]
In addition, since the ink is connected inside the slit structure, vibration generated when ink is ejected from a specific electrode may be applied to others, or the meniscus on the ejected electrode itself may generate unnecessary vibration. There arises a problem that the ink ejection direction is changed to produce a blurred image. More importantly, it has been found that when a voltage is applied to the electrodes arranged inside the slit, the charged colored particles in the vicinity are repelled, move and localize, and deposit and aggregate on portions other than the electrodes. For this reason, there are many problems such that the effective colored particles are lost or sometimes the opening is blocked, and the continuous use is not possible.
[0010]
The present invention has been made in view of the above points, and an object thereof is to provide an image forming apparatus having a high recording frequency and capable of stably forming a high-quality image with a high density.
[0016]
[Means for Solving the Problems]
  To achieve the above objective,The image forming apparatus of the present invention is formed on first and second support members disposed so as to face each other, and on each facing surface of the first and second support members. Supporting partMaterialIn the state of facing each other,Each extending vertically andA plurality of grooves forming openings at the tips thereof, a plurality of electrodes provided on the surfaces of the plurality of grooves, and formed on the opposing surfaces of the first and second support members, A partition wall for partitioning, and an ink in which charged colorant particles are dispersed in an insulating liquid is directed to the opening through the groove.Vertically upwardSupply means for supplying, and colorant particles in the ink supplied toward the opening are disposed in the vicinity of the opening.ToAggregating means for collecting and aggregating meansFrustrationA flying means for flying the collected colorant particles toward the recording medium and the partition wall are provided between the opening and the opening.OverflowingInkOuter peripheral surfaces of the first and second support membersInTowardsLet it drainTimesBefore and afterWritingA collecting means for collecting ink discharged from the collecting path;,Have
[0017]
  Further, the image forming apparatus of the present invention is formed on first and second support members disposed so as to face each other, and on each facing surface of the first and second support members. Second support partMaterialIn the state of being opposed to each other, a plurality of grooves that form openings at the tips thereof, a plurality of electrodes provided on the surfaces of the plurality of grooves, and ink in which charged colorant particles are dispersed in an insulating liquid Supply means for supplying toward the opening through the groove;10 ¹¹ It is formed of a material having an electrical resistance of ohm centimeters or more, is sandwiched between the first and second support members, and protrudes from each of the plurality of openings.Has multiple protrusionsShi,These protrusionsinkTheA guide member, a partition wall formed on each of the opposing surfaces of the first and second support members and partitioning the plurality of grooves, and colorant particles in the ink supplied toward the opening. Near the openingToAggregating means for collecting and aggregating meansFrustrationFlying means for flying the collected colorant particles toward the recording medium.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, an ink jet printer 1 as an image forming apparatus of the present invention includes a housing 2. A cylindrical platen roller 4 for holding a recording paper P as a recording medium and conveying it in a predetermined direction is provided at a predetermined position in the center of the housing 2. The platen roller 4 is made of a conductive material, is grounded, or acts as a counter electrode when given a predetermined potential as required.
[0019]
A paper feed cassette 6 in which a plurality of recording papers P are stacked is provided on the upper right side of the housing 2 in the drawing. The paper feed cassette 6 is mounted on the housing 2 in an inclined state, and the tip thereof is located in the housing 2. At a position adjacent to the front end of the paper feed cassette 6, a paper feed roller 8 is provided for picking up one by one from the uppermost recording paper P accumulated in the paper feed cassette 6.
[0020]
On the conveyance path of the recording paper P on the downstream side of the paper supply roller 8, a pair of conveyance guides 10 a and 10 b arranged to face each surface of the recording paper P is provided. Further, on the downstream side of the transport guides 10 a and 10 b, a pair of transport rollers 12 that sandwich the recording paper P transported through the transport guides 10 a and 10 b and transport the recording paper P toward the lower end of the outer peripheral surface of the platen roller 4. Is provided. Further, a pair of transport guides 14 a and 14 b for guiding the recording paper P transported by the transport roller 12 is provided between the transport roller 12 and the lowermost end of the platen roller 4.
[0021]
Between the conveyance guide 14b on the lower side of the conveyance path and the lower end of the platen roller 4, the recording paper P is pressed against the outer peripheral surface of the platen roller 4 so that the recording paper P adheres to the outer peripheral surface of the platen roller 4. A guide roller 15 is provided. A guide roller 16 that cooperates with the guide roller 15 is provided at a position sandwiching the lowermost end of the platen roller 4 with respect to the guide roller 15, that is, at a downstream side of the platen roller 4. The recording paper P is brought into close contact with the outer peripheral surface of the platen roller 4 by the pair of guide rollers 15 and 16 and conveyed.
[0022]
On the downstream side of the platen roller 4, a pair of conveyance guides 18 a and 18 b that guide the recording paper P that is nipped and conveyed by the platen roller 4 and the guide roller 16 are provided. A pair of transport rollers 19, a pair of transport guides 20, and a pair of transport rollers 21 are sequentially provided on the downstream side of the transport guides 18 a and 18 b, and a paper discharge tray 22 is provided on the downstream side of the transport rollers 21. . The paper discharge tray 22 is provided so as to protrude outside the housing 2.
[0023]
Thus, the recording paper P picked up one by one from the paper feed cassette 6 by the paper feed roller 8 is directed toward the lower end of the outer peripheral surface of the platen roller 4 via the transport guide 10, the transport roller 12 and the transport guide 14. Be transported. Near the lower end of the platen roller 4, the recording paper P is conveyed while being pressed against the outer peripheral surface of the platen roller 4 by a pair of guide rollers 15 and 16. At this time, ink droplets are ejected vertically upward from a recording unit (described later) provided facing the lowermost end of the platen roller 4, and a predetermined image is formed on the recording paper P. Then, the recording paper P on which an image is formed by passing between the platen roller 4 and the recording unit is placed on the paper discharge tray 22 via the transport guide 18, the transport roller 19, the transport guide 20, and the transport roller 21. Discharged.
[0024]
At a position spaced apart from the platen roller 4 by a predetermined distance, ink droplets are ejected according to an image signal to the recording paper P conveyed by the platen roller 4 to form a desired image on the recording paper P. A recording device 30 is provided.
[0025]
FIG. 2 shows the recording device 30 in detail. The recording apparatus 30 includes a recording unit 40 that is disposed below the platen roller 4 at a predetermined distance, and an ink tank 32 that stores ink to be circulated to the recording unit 40. The ink used here is formed by dispersing charged colorant particles (hereinafter referred to as toner) in an insulating carrier liquid.
[0026]
The recording unit 40 includes a substantially rectangular parallelepiped-shaped recording head 42 (described in detail later) disposed below the platen roller 4 so as to extend vertically downward. The recording head 42 has an upper end 42a opposed to the lowermost end of the platen roller 4 by a predetermined distance, and the longitudinal axis of the upper end 42a crosses the conveyance direction of the recording paper P, that is, the rotation axis of the platen roller 4. Are arranged so as to be substantially parallel to each other. In the present embodiment, the upper end 42a of the recording head 42 is disposed 0.1 to 3 mm away from the recording paper P being conveyed.
[0027]
Near the upper end 42 a of the recording head 42, a plurality of openings provided side by side in the longitudinal axis direction are formed. Inside the recording head 42, a plurality of ink supply paths 43 are formed for independently flowing ink from the vicinity of the lower end 42 b of the recording head 42 toward the openings. The respective ink supply paths 43 are parallel to each other and extend in the vertical direction.
[0028]
Further, the recording unit 40 includes a guide member 44 that surrounds the side surface and the lower surface side of the recording head 42. The guide member 44 supports the recording head 42 at a predetermined position, and forms an ink recovery path 45 with the outer wall of the recording head 42. That is, the ink supplied to the recording head 42 via each ink supply path 43 is raised in the recording head 42 and overflows from the opening of the upper end 42a. Then, excess ink overflowing from the opening is recovered through the ink recovery path 45.
[0029]
In a space below the guide member 44 and communicating with the ink collection path 45, a filter 46 is provided for allowing the collected excess ink to pass therethrough and removing foreign matter in the ink. The filter 46 has an opening that does not hinder the distribution of the toner particles in the ink.
[0030]
Further, the recording unit 40 has a plurality of electrodes 41 provided along the inner surface of each ink supply path 43 in the recording head 42. Each electrode 41 is connected to a drive circuit 48 (aggregating means, flying means, or recording means) for selectively applying a recording voltage to the electrode selected according to the image signal.
[0031]
An ink tank 32 containing ink is provided on the right side of the recording head 40 in the drawing. Connected between the recording unit 40 and the ink tank 32 is an ink supply pipe 34 for supplying the ink stored in the ink tank 32 to the ink supply path 43 in the recording head 42. In the middle of the ink supply pipe 34, a pump P1 for pumping up the ink in the ink tank 32 at a predetermined flow rate and pressure is provided.
[0032]
Further, an ink recovery pipe 36 is connected between the recording unit 40 and the ink tank 32 for recovering excess ink recovered through the ink recovery path 45 and passing through the filter 46 to the ink tank 32. Yes. In the middle of the ink recovery pipe 36, a pump P <b> 2 for sending excess ink overflowing from the tip of the recording head 42 to the ink tank 32 is provided. The pump P1, the ink supply pipe 34, and the ink supply path 43 function as supply means of the present invention. The ink recovery path 45 (guide member), the ink recovery pipe 36, and the pump P2 are recovery means of the present invention. Acts as
[0033]
In the ink tank 32, a density measuring device 31 that measures the optical transmittance of the ink stored in the ink tank 32 and measures the toner density of the ink, and a toner storage chamber that stores toner having a predetermined density 33, a carrier liquid storage chamber 35 that stores the carrier liquid, and a stirring device 37 that stirs the ink stored in the ink tank 32 are provided. The toner storage chamber 33 is provided with a toner supply unit 33a for supplying the consumed toner into the ink according to the toner concentration measured by the density measuring device 31, and the carrier liquid storage chamber 35 is provided with the ink in the ink. A carrier liquid supply unit 35a for replenishing the shortage of carrier liquid is provided. Therefore, the ink in the ink tank 32 is constantly stirred, and the toner density is constantly monitored and adjusted to a predetermined value.
[0034]
When the ink is circulated in the recording apparatus 30 configured as described above, first, the ink pumped from the ink tank 32 by the pump P1 is supplied to the plurality of ink supply paths in the recording head 42 via the ink supply pipe 34. 43. The ink supplied to each ink supply path 43 is raised in the ink supply path 43 and overflows from the opening at the upper end 42 a of the recording head 42. At this time, a plurality of ink meniscus 47 corresponding to the openings of the ink supply paths 43 are formed near the upper end 42 a of the recording head 42. Excess ink overflowing from the opening at the upper end 42 a of the recording head 42 flows downward through the ink recovery path 45 and is guided to the filter 46. The ink that has passed through the filter 46 is sucked by the pump P2 after the foreign matter is removed, and is collected in the ink tank 32.
[0035]
Further, near the lower end of the housing 2 of the inkjet printer 1 (see FIG. 1), a signal processing unit 24 that processes an image signal, and a signal output that outputs a signal processed by the signal processing unit 24 to the drive circuit 48 described above. And a control unit 28 for driving and controlling the above-described mechanisms (platen roller, transport roller, stirring device, pump, etc.) of the inkjet printer 1.
[0036]
Accordingly, the ink jet printer 1 configured as described above is operated as follows. First, the recording paper P is conveyed in a predetermined direction via the platen roller 4 as described above, and the ink is circulated in the recording unit 40 as described above. Then, a plurality of ink meniscus 47 is formed at each opening at the tip of the recording head 42.
[0037]
In this state, a predetermined recording voltage is applied to the electrode 41 selected according to the image signal via the drive circuit 48. Then, a predetermined electric field is formed between the selected electrode 41 and the platen roller 4, and the charged toner is separated and ejected from the ink by this electric field and is ejected toward the recording paper P. As a result, a predetermined image corresponding to the image signal is formed on the recording paper P.
[0038]
Next, the recording head 42 according to the first embodiment of the present invention incorporated in the recording unit 40 will be described in more detail with reference to FIGS.
3 is a perspective view of the recording head 42, and FIG. 4 is a plan view of the recording head 42 as viewed from the direction of the upper end 42a. The recording head 42 has a pair of substantially rectangular plate-like support members 51 and 52 and a substantially rectangular guide film 54 (guide member) sandwiched between the support members 51 and 52.
[0039]
The support members 51, 52 are made of a material having a high electrical resistivity, preferably 10¹²It is made of plastic having insulation properties of ohm-centimeter or more (higher electrical resistance is better, but polyether ketone, polycarbonate, ABS resin, etc. suitable for high-precision machining is preferable), ceramic, etc., and a thickness of 1 to 10 mm Is formed.
[0040]
The guide film 54 is a high resistance material having a thickness of 30 to 200 μm (for example, resin materials such as polyether siphon, polyester, polyethylene, fluororesin, polyimide, polypropylene, various ceramics, etc. 10¹¹A material having an electrical resistance of ohm centimeters or more).
[0041]
FIG. 5 shows one support member 51 as a representative. A plurality of rectangular grooves 51 a extending in parallel with each other are formed on one surface of the support member 51, that is, an inner surface (opposing surface) facing the guide film 54. The groove 51a forms the above-described plurality of ink supply paths 43 together with grooves (not shown) similarly formed in the other support member 52 in a state where the recording head 42 is assembled (state shown in FIG. 3). The number is formed according to the recording resolution.
[0042]
Each groove 51a is formed to have a depth of 50 to 500 μm and a width of 100 to 1000 μm, and the tip of each groove 51a is slightly in front of the tip of the support member 51 (forms the upper end 42a of the recording head 42 when combined). The base end of each groove 51 a extends to a position beyond the center of the support member 51. The base end of each groove 51a extending to substantially the center of the support member 51 is communicated with a rectangular recess 51b having the same depth as the groove 51a. The recess 51b forms an ink chamber 53 together with a recess (not shown) similarly formed in the other support member 52, and the ink supply described above for supplying ink to the ink chamber 53. A tube 34 is connected.
[0043]
As described above, by forming the plurality of grooves 51 a on the inner surface of the support member 51, a plurality of rectangular partition walls 55 that bound each ink supply path 43 are necessarily provided between the grooves 51 a. Then, the tip of the groove 51a (ink supply path 43) extending between the partition walls 55 is at a position retracted from the upper end 55a of the partition wall 55, that is, the upper end 42a of the recording head 42 by a predetermined distance (50 to 500 μm). An opening 56 (see FIG. 4) of the passage 43 is formed.
[0044]
An ink collection groove 57 (collection path) that is inclined downward toward the outer peripheral surface 51 c of the support member 51 is formed between the adjacent partition walls 55 and at the edge of the opening 56 at the tip of the ink supply path 43. Has been. The width of each ink recovery groove 57 is formed to be the same as the width of the opening 56, and the inclination angle is set to be an acute angle of 60 degrees or less.
[0045]
Furthermore, electrodes 41 made of a conductive material are formed to extend to the openings 56 by electroless plating on the surface of each groove 51 a formed in the support member 51, that is, the inner surface of the ink supply path 43. Each electrode 41 is made of, for example, a metal such as copper, chromium, aluminum, or nickel, and is electrically connected to the drive circuit 48 described above.
[0046]
The other support member 52 is formed in a target shape with respect to the support member 51, and is disposed and bonded so as to face each other so that the grooves of the support members 51 and 52 coincide. In this case, a recording film 42 is formed by sandwiching a guide film 54 described below between the support members 51 and 52.
[0047]
As shown in FIG. 6, the guide film 54 is formed in a substantially rectangular plate shape and has an upper end 54 a having a length that substantially matches the width of the upper end 42 a of the recording head 42 while being sandwiched between the pair of support members 51 and 52. have. The guide film 54 has a substantially triangular plate-like projection 59 having a sharp tip projecting from the upper end 54a in a number corresponding to the number of grooves (recording resolution) of the support member along the upper end 54a. That is, the plurality of protrusions 59 formed integrally with the upper end 54a of the guide film 54 are provided at the same pitch as the pitch of the grooves 51a formed in the support member 51 (52). Each ink supply path 43 is disposed so as to protrude from the opening 56 at the tip of the ink supply path 43 with a predetermined length. In this case, the guide film 54 is disposed so that only the protrusion 59 protrudes from the center of the opening 56 without the upper end 54 a of the guide film 54 protruding upward from the opening 56.
[0048]
FIG. 7 shows a partially enlarged view of the vicinity of the upper end 42a of the recording head 42 formed by sandwiching the guide film 54 by the pair of support members 51 and 52 as described above, that is, the vicinity of the ink ejection position. is there.
[0049]
The size of the protrusion 59 provided on the upper end 54a of the guide film 54 is the amount of ink supplied through the ink supply path 43, the size of the opening 56 of the ink supply path 43, or the ink wetness of the protrusion 59. The size of the projection 59 is set to a size at which the tip of the protrusion 59 is not submerged by at least the ink meniscus formed near the opening 56.
[0050]
For example, when the width of the opening 56 is 500 μm, the length of the bottom side of the protrusion 59 is set in the range of 300 to 400 μm, and the height of the protrusion 59 is set in the range of 300 to 1200 μm. When the recording characteristics of the recording head 42 were examined by changing the width and height of the protrusion 59 in various ways, the length of the bottom of the protrusion 59 was set to about half the width of the opening, and the height was the same as the length of the bottom. It has been found that stable recording characteristics can be obtained by setting the length between three times.
[0051]
Moreover, the shape of the protrusion 59 can be made into the shape as shown to Fig.8 (a)-(d), for example. That is, the shape of the protrusion 59 may be a so-called spire shape that is sharp from the bottom side to the tip side disposed on the upper end 54 a of the guide film 54. Further, the protrusion 59 may be a rotating body obtained by rotating a flat plate having a shape as shown in FIG. 8 around its central axis. In this case, the protrusion 59 closes the opening 56 of the ink supply path 43. It is necessary to form in the size without.
[0052]
That is, the protrusion 59 has such an outer shape that the toner in the ink can smoothly move to the tip of the protrusion when an electric field directed to the platen roller 4 is applied to the ink supplied through the ink supply path 43. As long as it has good wettability (lipophilicity) with the ink. In particular, the protrusion 59 is preferably made of a material having a critical surface tension showing wettability of 25 dyne / cm 2 or more.
[0053]
Between the two adjacent protrusions 59, that is, between the two adjacent openings 56, there is a partition wall 55 for separating the ink meniscus 47 individually formed near each opening 56 along each protrusion 59. Is provided. Each partition 55 has an upper end 55a (upper end 42a of the recording head 42) that protrudes about 50 to 500 μm in the recording paper P direction (upward) from the opening 56 at the end of each ink supply path 43. Further, it is desirable that the corners at which the partition wall 55 faces the ink supply path 43 or the ink collection groove 57 are slightly chamfered or not chamfered at all. That is, by not chamfering the corner portion of the partition wall 55, it is possible to prevent the ink from spreading at the corner portion and to prevent the ink meniscus 47 from cross-linking.
[0054]
An oil repellent surface 60 that repels ink is provided at the upper end 55 a of each partition wall 55. The oil-repellent surface 60 is formed of a material having a critical surface tension of 25 dyne / cm or less, such as a fluororesin, a fluorine paint, a silicone resin, or a silicone paint, when an isoparaffin solvent is used as the ink. It can exhibit oiliness (anti-wetting property). Thus, by providing the oil repellent surface 60 on the upper end 55a of each partition wall 55, it is possible to prevent the adjacent ink meniscus from being bridged. Further, by providing the oil-repellent surface 60, it is possible to prevent the ink meniscus from being bridged even when the height of the partition wall 55 is the same height as the opening 56 at the tip of the ink supply path 43.
[0055]
By providing the partition wall 55 configured as described above between the protrusions 59, it is possible to prevent the adjacent ink meniscus 47 from being bridged, and to prevent the ink droplet ejection direction and the ejection frequency from being disturbed due to the ink crosslinking, Ink droplets can be ejected stably. Each partition wall 55 functions to define both ends of an ink collection groove 57 that is inclined from the edge of each opening 56 toward the outer peripheral surface of the support member.
[0056]
Here, ink components used in the recording apparatus 30 will be described. The ink is configured by dispersing toner as charged colorant particles in a carrier liquid as an insulating liquid at a ratio of about 2 to 7% by weight.
[0057]
The carrier liquid has an electrical resistivity of at least 10⁹ Isoparaffinic solvent (for example, 10 ohm · cm or more, preferably an insulating liquid)¹²-10¹³It is a dispersion medium composed of an organic solvent such as Isopar G, H, K, L, M (trade name) having the above electric resistance, silicon oil, hexane, pentane, octane or the like. The electrical resistivity was measured using PRECISION LCR METER 4284A manufactured by HEWLETTPACKARD; LIQUID TEST FIXTURE 16452A as a measuring head.
[0058]
The toner has a particle diameter of about 0.01 to 5 μm and is a metal soap for charging such as zirconium octylate or lithium octylate for charging to a predetermined potential (here, positive potential) in a carrier liquid. And resin particles containing coloring components and the like.
[0059]
The ink is basically the same as the liquid developer used in electrophotography or the like, but is required to have a higher electric resistance than the liquid developer.
In other words, when the electric resistance of the ink is low, the electric field does not act only on the charged toner, and a fatal failure that the separating action of the toner does not become weak occurs. Also, if the electrical resistance of the ink is low, the carrier liquid itself is energized like the conventional electrostatic ink jet, so the entire recording liquid is charged and discharged completely without any distinction between toner and carrier liquid, The effect of the present invention is completely lost. For this reason, an ink having a higher electric resistance is required.
[0060]
Factors that undesirably reduce electrical resistance include metal soaps such as naphthenic acid, octylic acid, and stearic acid that are generally added to disperse toner or improve chargeability (for example, zirconium naphthenate and zirconium octylate) It is conceivable to add various surfactants. Since these generally lower the electrical resistance of the recording liquid, it is necessary to devise in order to make it as small as possible.
[0061]
The electrical resistance of the ink that can be used in the recording apparatus 30 of the present embodiment to obtain good recording characteristics (a state in which only toner is separated and discharged from the recording liquid is called good) is 10⁸ This is an ohm-centimeter or more, and this level of electrical resistance reduces flow and bleeding on normal recording paper P.^TenAn electrical resistance of ohm-centimeter or more further improves the sharpness of the image outline. This shows that it is desirable that the electrical resistance of the ink be as high as possible.
[0062]
In order to obtain such a high electric resistance as a recording liquid, a higher electric resistance is required for the carrier liquid before the toner is dispersed. Considering the effects of the additives mentioned above, 10^TenMore than ohm centimeters are necessary. In order to disperse the toner in the carrier liquid having such an electric resistance, the above-mentioned additive is added to the minimum amount, and approximately 10⁸ The electrical resistance drops to about ohm centimeters. The necessary minimum here means that it is necessary to maintain a level having no practical problem from the evaluation of the charging and dispersion stability of the toner, and the specific value varies depending on the material used. Therefore, the higher the electrical resistance of the original carrier liquid, the easier it is to use a dispersion aid or charge control agent when preparing the recording liquid.
[0063]
As described above, the components of the ink are basically the same as those of the liquid developer used in electrophotography, but the electric resistance of the carrier liquid is required to be higher than these. As a liquid developer used in generally known electrophotography, a polymer dispersed particle having a viscosity obtained by polymerizing a monomer containing a colorant in a solution is relatively free of dispersant and other conductive components. Many of them are not good records. Therefore, it is necessary to reduce the conductive component in accordance with the object of the present invention.
[0064]
Also, a thickener for suppressing toner precipitation should not be added as much as possible. As the ink used in the present invention, toner fine particles obtained by kneading a resin, a colorant, and a charge control agent, and pulverizing to a desired particle size after cooling are coated with a small amount of a dispersion aid, and if necessary, a small amount of A material dispersed in a carrier liquid by adding a swelling solvent or the like is suitable for making an ink having high electrical resistance.
[0065]
Further, in order to discharge the toner using the electric repulsive force, it is required that the charge amount of the toner is also stable, and when measured as a zeta potential, it is preferably 60 millivolts or more.
[0066]
On the other hand, a toner having a large particle diameter is suitable because it has a high electrophoretic speed but is susceptible to precipitation. When the average particle diameter is 0.01 μm or less with respect to toner discharge, an image with blurring, which seems to be difficult to separate from the carrier liquid, was generated. In order not to absorb the liquid at all, for example, no bleeding or flow occurs even when recording on a metal surface, the toner particle diameter is preferably 0.1 μm or more. In addition, large particles depend on the precipitation preventing mechanism in the recording apparatus, but particles exceeding about 5 micrometers are difficult to use because they precipitate in a very short time. It is necessary to select according to the apparatus as appropriate. If used intermittently, it is preferably 4 micrometers or less. For zeta potential measurement, LAZER ZEE of PEN KEM, USA
METER M-501 was used.
[0067]
Next, an ink droplet flying operation in the recording head 42 configured as described above will be described with reference to FIG.
First, the ink 70 stored in the ink tank 32 is pumped up by the pump P 1 through the ink supply pipe 34, and the ink 70 is supplied into the ink chamber 53. When the ink chamber 53 is filled with the ink 70, the ink 70 is raised through the plurality of ink supply paths 43 and overflows from the opening 56 at the tip of each ink supply path 43.
[0068]
The ink 70 overflowing from the opening 56 of each ink supply path 43 flows out through the ink collection groove 57 defined by the partition walls 55 provided on both sides of each opening 56, and the outer peripheral walls 51c, It flows downward along 52c. The ink 70 that flows along the outer peripheral walls 51 c and 52 c is collected into the ink tank 32 via the ink collection path 45, the filter 46, and the ink collection pipe 36.
[0069]
When the ink 70 is circulated in the recording unit 40 in this way, the ink 70 wets along the protrusions 59 of the guide film 54 in the vicinity of the opening 56 of each ink supply path 43, and the supply pressure of the ink 70 and the ink An ink meniscus 47 as shown in FIG. 9 is formed by the surface tension of 70 and the capillary action of the ink recovery groove 57.
[0070]
In this case, the upper end 55a of the partition wall 55 provided between the openings 56 is made higher than the opening 56, the oil-repellent surface 60 is formed on the upper end 55a, and the corners of the partition wall 55 are not chamfered. It is possible to prevent cross-linking between the ink meniscuses formed individually.
[0071]
With the ink meniscus 47 formed in the vicinity of each opening 56 as described above, a bias voltage of about 1000 to 1600 volts is applied to the electrode 41 provided along the inner surface of each ink supply path 43 via the power supply 77. Then, an electric field is formed from each electrode 41 toward the platen roller 4 (recording paper P). Under the influence of this electric field, the toner 71 in the ink 70 receives an electrostatic repulsive force from the electrode 41, and the toner migrates toward the apex of the ink meniscus 47, that is, the apex of the protrusion 59 of the guide film 54.
[0072]
In this case, since the ink meniscus 47 is tapered toward the apex, the toner 71 migrated toward the apex of the ink meniscus 47 is aggregated in the vicinity of the apex of the protrusion 59, and the toner aggregate 74 is present here. Is formed. When the toner 71 is aggregated, a larger electrostatic force is applied to the aggregate 74. Here, the bias voltage is set so that the aggregate 74 does not fly from the ink meniscus 47. Further, the distance between the tip of the recording head 42 and the platen roller 4 is set so that the aggregate 74 does not fly when a bias voltage is applied to each electrode 41.
[0073]
On the other hand, the carrier liquid 72 separated from the toner 71 by applying a bias voltage to each electrode 41 does not move toward the apex of the ink meniscus 47, but from the skirt of the ink meniscus 47 via the ink recovery groove 57. Leaked. That is, the carrier liquid 72 has negative ions due to the mutual charging action with the toner 71 (positive polarity), and is not raised by the electric field acting on the ink meniscus 47. Accordingly, the carrier liquid 72 separated from the toner 71 is forced to flow out from the bottom of the ink meniscus 47 due to the surface tension of the ink (capillary action of the ink collecting groove 57), gravity, and the electrostatic suction force that is partially generated. Is done.
[0074]
As a discharge path for the carrier liquid 72, it is desirable that the ink collection groove 57 formed adjacent to each opening 56 has a shape that can efficiently discharge the carrier liquid 72 separated by the aggregation of the toner 71. By efficiently discharging the carrier liquid 72, the ink meniscus 47 can be stabilized, the recording speed can be increased, and the ejection frequency can be increased.
[0075]
The ink collecting grooves 57 may be provided only on one side without being provided on both sides of the opening 56, but are desirably provided on both sides in order to maintain the symmetry of the ink meniscus. Further, in order to efficiently discharge the carrier liquid 72, it is desirable that the edge between the ink supply path 43 and the ink recovery groove 57 is chamfered, but the tip of the electrode 41 is exposed as in the present embodiment. It is good also as a structure. In this way, a strong electric field can be generated by exposing the tip of the electrode 41 at the edge of the opening 56.
[0076]
In the state where the toner 71 and the carrier liquid 72 are separated as described above, the ejection voltage is selectively applied to the electrode 41 selected according to the image signal in a superimposed manner. The ejection voltage applied in a superimposed manner is about 150 to 800 volts, and a stronger electric field is generated in the ink meniscus 47 near the opening 56 having the electrode 41 to which the ejection voltage is applied than when a bias voltage is applied.
[0077]
Due to this electric field, an electrostatic force stronger than the binding force such as surface tension acting on the aggregate 74 acts on the aggregate 74, and the aggregate 74 is separated from the ink meniscus 47 and is directed toward the recording paper P. As a flight. Thereby, dots by the ink droplets 76 are formed on the recording paper P, and a desired image is formed on the recording paper P by operating the plurality of electrodes 41 according to the image signal.
[0078]
As described above, according to the recording head 42 according to the present embodiment, the carrier liquid separated from the toner can be forcibly discharged through the ink collection groove 57, so that the separation of the toner and the carrier liquid can be performed efficiently. In addition, the toner aggregation efficiency can be increased, and the ink droplet ejection frequency can be increased. For example, in the recording head 42 described above, an ejection frequency of 500 to 1 kilohertz could be achieved. The ejection frequency tended to increase as the opening diameter of the ink supply path 43 was reduced, and the ejection frequency when the opening diameter was set to 100 μm was 2 kilohertz.
[0079]
As a method for increasing the ejection frequency without reducing the opening diameter, there is a method of providing a conductive material near the tip of the protrusion 59 of the guide film 54. According to this method, by forming a metal region of about 30 to 100 μm at the tip of the protrusion 59, a discharge frequency of 2 kilohertz can be achieved when the opening diameter is set to 500 μm.
[0080]
Further, the partition wall 55 defining both sides of the ink collecting groove 57 and the oil repellent surface 60 provided on the upper surface 55a can prevent the ink meniscus from being cross-linked between the openings 56, so that the ink droplets can fly. Undesired vibration of the ink meniscus and disturbance in the ejection direction can be prevented, stable recording can be performed, and a high-quality image can be formed.
[0081]
Further, it is known that the diameter of the ink droplets flying from the opening 56 varies depending on the magnitude of the applied ejection voltage and the application time, and when ink containing toner having an average particle diameter of 1 μm is used, the ejection voltage Is changed to 150 to 600 volts, the diameter of the ink droplet changes in the range of about 15 to 120 μm. Further, when the signal voltage application time is changed by 50 to 500 microseconds (at the recording frequency of 1 KHz), a change of 10 μm to 300 μm is shown. Thus, by adjusting the applied voltage and time, the particle size of the ink droplet can be changed, so that an ink droplet having a small particle size can be ejected from a large opening, and the ink supply path due to drying of the ink Clogging can be prevented and high-density recording is possible.
[0082]
As described above, according to the recording head according to the first embodiment, unlike the conventional ink jet printer, the toner aggregate that is a solid or semi-solid component is separated from the ink without forming a liquid as a recording image. Thus, a recorded image can be formed. For this reason, there is no occurrence of an image defect such as so-called feathering in which ink droplets flow after reaching the recording paper P, or penetrate and penetrate between the fibers of the recording paper P due to capillary action. The carrier liquid and the toner are separated when ink droplets are ejected, but not completely 100%, and the toner reaches the recording paper P in a state wetted by the carrier liquid. However, since the accompanying carrier liquid is small, the recorded image does not flow. For this reason, a sharp image can be recorded even on a non-absorbing image receptor such as metal or plastic, which is an advantage not found in conventional ink jet printers.
[0083]
Next, a recording head 80 according to a second embodiment of the invention will be described with reference to FIGS. The recording head 80 generally has a structure in which the two recording heads 42 of the first embodiment described above are stacked, and the basic configuration is the same as the recording head 42. Accordingly, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Only parts different from those in the first embodiment will be described.
[0084]
10A is a side view of the recording head 80, and FIG. 10B is a plan view of the recording head 80 as viewed from the upper end side. The recording head 80 is configured by overlapping two recording heads 82 and 82 'having substantially the same configuration as the recording head 42 of the first embodiment described above so that the upper ends thereof are arranged in the same plane. ing. Each recording head 82, 82 ′ has a plurality of openings 56 arranged in a line in the longitudinal direction at the upper end thereof, and each opening 56 is set so as to be shifted by ½ pitch in the longitudinal direction. The recording heads 82 and 82 'are combined so that the tips of the recording heads 82 and 82' (tips of the projections 59 of the guide film 54) are at the same height.
[0085]
Each of the recording heads 82 and 82 'has a pair of support members, and each of the support members 81 and 81' has an ink on a surface opposite to the surface on which the groove 51a is formed, as shown in FIG. Has a discharge groove 83 for discharging the gas. Further, between each groove 51a and the discharge groove 83, an ink recovery groove 57 is formed which is bounded by partition walls 55 provided on both sides of each groove 51a and is inclined downward from the groove 51a toward the discharge groove 83. Has been. Then, the two recording heads 82 and 82 'are combined so that one of the support members 81 and 81' on which the discharge groove 83 is formed are adjacent to each other, that is, the discharge groove 83 is matched. The recording head 80 of the form is formed. The discharge grooves 83 formed in the opposing support members 81 and 81 ′ form an ink discharge path 85 when the recording head 80 is formed.
[0086]
Accordingly, when ink is circulated in the recording head 80, the ink supplied through the plurality of ink supply paths 43 overflows from the openings 56 and passes through the ink collection grooves 57 provided on both sides of the openings 56. And is collected through the outer peripheral wall of the recording head 80 and the ink discharge path 85. When the ink is circulated in this way, an ink meniscus is formed along the protrusion 59 protruding from each opening 56. In the state where the ink meniscus is formed, a desired image is formed on the recording paper P by selectively applying a recording voltage to the electrode 41 selected according to the image signal.
[0087]
Therefore, in the recording head 80 of the present embodiment, the same effect as that of the recording head 42 of the first embodiment described above can be obtained, and in addition, a higher density of openings 56 can be arranged. It can cope with higher-definition image formation. In the present embodiment, two recording heads are combined, but more recording heads can be combined as necessary.
[0088]
Further, according to the recording head 80 according to the present embodiment, since a thin and long recording head can be easily realized, for example, for four recording heads, so-called color recording of black, cyan, magenta, and yellow, respectively. A recording liquid in which the three primary colors and black toner for inking are dispersed is filled, and color separation images are sequentially recorded on the recording paper, whereby an image can be formed in color. In this case, since the fluidity is lost when the ink droplet reaches the recording paper P, it is not necessary to dry for each color, and the process proceeds immediately to the recording process for the next color. Also suitable for recording.
[0089]
Next, an example in which the coating 88 is applied to each electrode 41 formed in the plurality of ink supply paths 43 in the recording head 42 according to the first (or second) embodiment described above will be described.
[0090]
As shown in FIG. 12, a coating 88 extending to the opening 56 is applied to the surface of the electrode 41 provided in each ink supply path 43 of the recording head 42. The coating 88 is made of a material having high electrical resistance such as resin (polycarbonate, epoxy, acrylic, silicon, etc.) insoluble in the ink 70, silicon nitride, amorphous silicon, etc., and has a thickness of about 1 to 20 microns and the electrode 41. Is completely covered up to the end of the opening 56. That is, the tip of each electrode 41 is exposed in each opening 56.
[0091]
By providing the coating 88 having a high electric resistance on the surface of the electrode 41 in this manner, the transfer of electric charge (energization) from the electrode 41 to the ink 70 is completely stopped, and thus the electric resistance of the carrier liquid 72 is low. However, the carrier liquid 72 can be prevented from being charged and charged. For this reason, it is possible to maintain a state where only the toner 71 is discharged without discharging the carrier liquid 72. In this case, even if the ink whose resistance is lowered to about 106 ohm centimeters is used, relatively good recording can be performed, and the ink 70 can be easily manufactured. However, when adopting a structure in which the supply systems of the ink 70 cross each other, an electrical crosstalk of the applied voltage is generated, and thus structural attention is required. The effect of applying an insulating coating to the electrode 41 becomes more necessary when suppressing the change in the recording dot diameter due to a change in resistance of the ink 70 with the passage of time, particularly when trying to control the size of the recording particles by voltage modulation.
[0092]
Next, a recording head 90 according to a third embodiment of the invention will be described with reference to FIG.
As shown in FIG. 13, the recording head 90 has a pair of support members 91 and 92 having a substantially rectangular plate shape. These support members 91 and 92 are formed similarly to the support members 51 and 52 of the recording head 42 according to the first embodiment described above. The support members 91 and 92 are combined so that the groove 91a (92a) formed on one surface of each support member 91 and 92 is not opposed, and the other surface where no groove is formed is opposed. That is, the recording head 90 has a plurality of grooves for distributing ink on the outer peripheral surface thereof, and the guide film 54 is sandwiched by the other surface where the grooves of the support members 91 and 92 are not formed. Has been. The plurality of protrusions 59 provided on the upper end 54 a of the guide film 54 are provided so as to protrude from the upper end 90 a of the recording head 90 corresponding to the grooves formed in the support members 91 and 92.
[0093]
The grooves 91 a and 92 a formed in the respective support members 91 and 92 are connected in a one-to-one correspondence via the upper end 90 a of the recording head 90, and the rectangular portion 93 to which each groove is connected is the recording head 90. Retracted from the upper end 90a by a predetermined distance. In other words, on both sides of each rectangular portion 93, a tip end portion of the partition wall 55 that borders each groove formed in each support member 91, 92 is interposed, and an upper end 55 a of each partition wall 55 protrudes from the rectangular portion 93. Is provided. And the protrusion 59 of the guide film 54 protrudes from each rectangular part 93, and the ring-shaped electrode 94 is each provided in each rectangular part 93 so that these protrusions 59 may be enclosed.
[0094]
When the ink is circulated through the recording head 90 configured as described above, the ink is supplied to each rectangular portion 93 via each groove 91a formed on the outer peripheral surface of one supporting member 91, and the supporting member on the opposite side is supplied. It discharges | emits through each groove | channel 92a (not shown) formed in 92. FIG. In this case, in the first embodiment described above, the recording head 42 is opposed to the recording paper P so as to be substantially orthogonal (extends in the vertical direction), but in the recording head 90 according to the present embodiment, The recording head 90 is inclined at a predetermined angle in order to allow ink distribution. That is, the recording head 90 is tilted so that the ink supply side (support member 91) is positioned above and the ink discharge side (support member 92) is positioned below.
[0095]
As described above, when ink is circulated through the recording head 90, the ink passing through each rectangular portion 93 wets along each projection 59, and an ink meniscus is formed near the rectangular portion 93, projection 59, and electrode 94. The A recording voltage is selectively applied from the driving circuit 48 to the electrode 94 selected according to the image signal in a state where independent ink meniscuses are formed in the respective rectangular portions 93, and the recording paper. Ink droplets fly toward P, and a desired image is formed on recording paper P.
[0096]
As described above, even when the recording head 90 according to the present embodiment is used, the same effects as when the recording head 42 according to the first embodiment described above is used can be obtained. In addition, by providing a cover that covers the groove on the outer peripheral surface of each support member 91, 92, a pipe-shaped ink flow path is formed along the outer peripheral surface of each support member 91, 92. May be forced to circulate. In this case, there is no need to tilt the recording head 90.
[0097]
Next, a recording head 100 according to a fourth embodiment of the invention will be described with reference to FIGS. 14 is a perspective view of the recording head 100, and FIG. 15 is a cross-sectional view of the recording head 100 taken along the line AA in the drawing.
[0098]
The recording head 100 has the same configuration as the recording head 42 according to the first embodiment described above except that it does not have the guide film 54. Therefore, the same parts as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Only parts different from the first embodiment will be described.
[0099]
By the way, in the recording heads according to the first to third embodiments described above, the protrusion 59 is arranged at the ink ejection position in the vicinity of the opening or the ring-shaped electrode. This protrusion 59 is the ink formed in the vicinity of the protrusion position. The purpose is to stabilize the meniscus and agglomerate the toner with high efficiency, to quickly absorb the vibration of the ink meniscus generated during the ejection of the ink droplet, and not to affect the ejection of the next ink droplet. That is, by providing the protrusion 59, the ejection stability of the ink droplet can be improved.
[0100]
However, these protrusions 59 are not absolutely necessary for the present invention. Therefore, even when the recording head 100 of the present embodiment having no guide film is used, the same effects as those of the above-described embodiments can be obtained.
[0101]
That is, according to the recording head 100, the discharge of ink overflowing from the opening 56 can be stabilized mainly by the capillary effect of the partition wall 55 and the ink recovery groove 57, and the shape of the ink meniscus on the opening 56 can be stabilized. . Thereby, the restoring property of the ink meniscus can be improved, and the ejection frequency of the ink droplet can be stabilized.
[0102]
Further, ink clogging can be reduced as compared with the recording head 42 according to the first embodiment described above. That is, according to the recording head 100 of the present embodiment, there is an advantage that there is no problem that toner sticks due to drying at the tip of the protrusion 59 when the apparatus is stopped. And there are maintenance advantages.
[0103]
In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible within the scope of this invention. For example, the shape of the opening 56 at the tip of the ink supply path 43 does not need to be a square, and the cross-sectional shape of the electrode 41 is a well type or ring in which the electric field at the center of the opening 56, that is, the tip of the protrusion 59 is slightly lower than the periphery. Any structure may be used as long as it forms a toroidal electric field. That is, it is only necessary to have a shape that substantially surrounds the ridges of the protrusion 59. Specifically, all cross-sectional shapes such as a circular shape (ring shape) and an elliptical shape are possible. Further, a discontinuous (partial) electrode arrangement such as a U-shape, a parallel plate shape, or a stripe shape may be employed without covering the entire opening end with an electrode.
[0104]
Further, in each of the above-described embodiments, the width of the partition wall 55 (distance between adjacent openings) is drawn as the same level as the opening 56, but is not limited to this and can be made smaller. Is possible. In this case, in addition to sufficiently increasing the height of the partition wall 55, by sharpening all the corners of the partition wall 55, the effect of cutting off the spread of the ink is increased. When the partition wall 55 is formed of polycarbonate resin or the like using an ink having a surface tension of about 18 to 30 millinewtons / meter used in the present invention, the corner portion of the partition wall 55 has a chamfer of 100 microns or less and a curved surface. In this case, when the radius was 100 microns or less, the ink meniscus was not cross-linked between the adjacent openings 56 during normal recording.
[0105]
Furthermore, the arrangement direction of the protrusion 59 may be set to a direction different from the above-described embodiments by 90 degrees, and the shape of the protrusion 59 can be appropriately selected. If the bottom of the protrusion 59 is made smaller, the base of the ink meniscus formed around the protrusion becomes smaller and it becomes difficult for the ink to crawl up on the partition wall. However, the amount of toner aggregation decreases, so it should be adjusted according to the purpose. is there. Further, in each of the above embodiments, the protrusion 59 is formed with the guide film 54 so as to be arranged with high accuracy. However, the protrusion 59 is divided into a plurality of parts or arranged only in the opening. Various modifications such as a sheath structure are possible. In the embodiment, all the protrusions are arranged in the central portion of the electrode. However, this is shown as a preferable arrangement example, and although the recording effect is somewhat reduced, one side of the groove is used in order to simplify the device structure. It is also included in the gist of the present invention to arrange protrusions on the surface.
[0106]
In this embodiment, a bias voltage is applied to the electrode. However, a bias voltage may be applied to the platen roller 4 that is the counter electrode. In short, recording is performed between the platen roller 4 and the electrode. It is sufficient that a sufficient bias voltage is applied.
[0107]
【The invention's effect】
As described above, since the image forming apparatus of the present invention has the above-described configuration and operation, a high recording frequency can be achieved, and a high-quality image with high density can be stably formed.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an ink jet printer as an image forming apparatus of the present invention.
FIG. 2 is a schematic view showing a recording apparatus incorporated in the ink jet printer of FIG. 1;
FIG. 3 is a perspective view showing a recording head incorporated in the recording apparatus of FIG. 2;
4 is a plan view of the recording head of FIG. 3 as viewed from the upper end thereof.
5A is a front view showing a support member that constitutes the recording head of FIG. 3; FIG. FIG. 5B is a side view showing the support member of FIG.
6 is a schematic view showing a guide film incorporated in the recording head of FIG. 3. FIG.
7 is a partially enlarged view showing the vicinity of the upper end of the recording head of FIG. 3 in an enlarged manner.
FIG. 8 is a view showing a modification of the protrusions of the guide film of FIG.
FIG. 9 is an operation explanatory diagram for explaining a recording operation in the recording head of FIG. 3;
FIG. 10A is a side view showing a recording head according to a second embodiment of the invention. FIG. 10B is a plan view showing the recording head of FIG.
11 is a schematic view showing one supporting member constituting the recording head of FIG.
FIG. 12 is a schematic view showing a recording head in which a coating is applied on an electrode.
FIG. 13 is a perspective view showing a recording head according to a third embodiment of the invention.
FIG. 14 is a perspective view showing a recording head according to a fourth embodiment of the invention.
15 is a cross-sectional view of the recording head of FIG. 14 cut along the line AA.
[Explanation of symbols]
1 ... Inkjet printer,
4 ... Platen roller,
30 ... Recording device,
32 ... Ink tank,
40 ... Recording unit,
41 ... electrodes,
42 ... recording head,
43. Ink supply path,
44 ... guide member,
45. Ink collection path,
51, 52 ... support members,
51a ... groove,
54 ... Guide film,
55 ... partition wall,
56. Opening,
57. Ink collection groove,
59 ... Protrusions.

Claims (8)

First and second support members arranged to face each other;
Wherein formed on the first and the opposing face of the second support member, a plurality of forming said at first and second state in which the support member is closely opposed, and opening at its tip, respectively extend in the vertical direction And the groove
A plurality of electrodes provided on the surfaces of the plurality of grooves;
Partition walls formed on the opposing surfaces of the first and second support members and partitioning the plurality of grooves;
Supply means for supplying ink formed by dispersing charged colorant particles in an insulating liquid vertically upward toward the opening through the groove;
And aggregation means for agglutination Te the opening near smell colorant particles in the ink which is supplied toward the opening,
A jetting unit for jetting toward the colorant particles Rico collector by the aggregation device to a recording medium,
Provided between the barrier ribs, and Ru times Osamuro the overflowing ink from the opening is discharged toward the outer circumferential surface of the first and second support members,
And recovery means for recovering ink discharged from the front Machinery Osamuro,
An image forming apparatus comprising: First and second support members arranged to face each other;
In the formed on the first and on the opposing surface of the second support member, a state in which said first and second support member proximate not face to a plurality of grooves forming an opening at its tip,
A plurality of electrodes provided on the surfaces of the plurality of grooves;
Supply means for supplying ink formed by dispersing charged colorant particles in an insulating liquid toward the opening through the groove;
10 ¹¹ are formed by ohmic cm or more materials having an electrical resistance, the sandwiched with the first and second support members, have a plurality of projections projecting from each of the plurality of openings, the ink these projections a guide member which guides a
Partition walls formed on the opposing surfaces of the first and second support members and partitioning the plurality of grooves;
The colorant particles in the ink supplied toward the opening and aggregating means for agglutination Te said opening near smell,
A jetting unit for jetting toward the colorant particles Rico collector by the aggregation device to a recording medium,
An image forming apparatus comprising: A collection path provided between the partition walls for discharging ink overflowing from the opening;
  Recovery means for recovering ink discharged from the recovery path;
  The image forming apparatus according to claim 2, further comprising: The partition tip is opposed to the recording medium, the image forming apparatus according to claim 1 or 3, characterized in that protrudes from the opening by a predetermined distance. Upper Machinery Osamuro The image forming according to claim 1 or 3, characterized in that it has an inclined shape in order to discharge the ink toward the outer circumferential surface of the first and second support members from the opening apparatus. Tip the partition walls opposed to said recording medium has a material of oil repellency against the ink, the upper Machinery Osamuro to claim 4, characterized in that it consists of a material oleophilic to said ink The image forming apparatus described. Upper Machinery Osamuro is defined between adjacent said partition wall, an image forming apparatus according to the ink by capillary action to claim 6, characterized in that the ink recovery groove leading to the collecting means from the opening . On the surface of each electrode is exposed to the ink, an image forming apparatus according to claim 1 or 2, characterized in that the insulating material is coated.

Images