JP2008284523A - Functional material coating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a functional material coating device superior in ejection stability without depending on the viscosity of a coating liquid of a functional material, also capable of forming a good functional film with a suppressed dispersion of the film thickness on the outer circumferential surface of a columnar or cylindrical article to be coated, and a method of applying the functional material. <P>SOLUTION: A liquid columnar coating liquid 14 is ejected from a nozzle 123 of an annular ejection head 12 and the ejected liquid columnar coating liquid 14 is atomized into liquid droplets, by continuously pressurizing the coating liquid 14 containing the functional material, to apply to an article 10 to be coated. Since the coating liquid 14 is ejected by continuously being pressurized like this, the coating liquid 14 even having a high viscosity, or for example, a coating liquid having the viscosity range from around 3 mPa s, close to water, to an around 300 mPa s, can be stably ejected and applied to the article 10 to be coated. Also, the good functional film with a suppressed dispersion of the film thickness can be obtained on the outer circumferential surface of the columnar or cylindrical article to be coated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a functional material coating solution.

  Conventionally, an electrophotographic member such as a photosensitive drum mounted on a copying machine has been mainly performed by a dip coating method (dip (DIP) coating method). In this method, a considerably larger amount than that actually applied is required for performance management of the material, which is wasteful. In addition, since precise control of the dipping rate and the drying rate is required, the ratio of film thickness variations due to environmental fluctuations and the like was high.

  On the other hand, in recent years, studies on application of inkjet technology to industrial applications are actively conducted. Inkjet is widely used for color printing and photo printing at home, but examples of printing are not paper, but examples of using coating liquid as industrial material instead of ink have been announced.

  For example, Patent Documents 1 to 4 propose using such an ink jet technique to form a functional film such as a polymer film or a conductive film to manufacture an industrial product such as an electrophotographic member. .

Japanese Patent Laid-Open No. 11-19554 JP 2001-88306 A US Pat. No. 6,245,745 JP 2004-248272 A

  However, in the above proposal, since the functional film is applied by a so-called drop-on-deman type discharge method in which droplets are directly discharged from a nozzle by intermittently applying a discharge pressure, the coating liquid has a high viscosity. In this case, the present situation is that stable discharge performance cannot be obtained.

  On the other hand, there are various functional material coating liquids that form functional films, ranging from low viscosity to high viscosity, which do not depend on the viscosity of the coating liquid, stably maintain discharge performance, and have good functional films. Is required to be formed.

  In addition, when a functional film is formed on the outer peripheral surface of a columnar or cylindrical object to be coated, if a linear discharge head is employed, when the discharge head vibrates, vibration at the longitudinal end portion and the central portion thereof Since the degree is different, the thickness of the functional film may vary.

  Accordingly, the object of the present invention is to provide a good functional film that does not depend on the viscosity of the coating liquid of the functional material, has excellent ejection stability, and suppresses variations in film thickness on the outer peripheral surface of the columnar or cylindrical coated object. Functional material coating apparatus and functional material coating method capable of forming a functional material.

The above problem is solved by the following means. That is,
The invention according to claim 1
An annular coating liquid chamber to which a coating liquid containing a functional material is supplied, and a nozzle that communicates with the annular coating liquid chamber and is disposed on the inner peripheral side of the annular coating liquid chamber to discharge the coating liquid An annular coating liquid discharge head having
Pressurizing means for continuously pressurizing and supplying the coating liquid to the coating liquid chamber, and discharging the coating liquid in a liquid column shape from the nozzle;
Droplet forming means for forming the coating liquid discharged from the nozzle in a liquid column shape into droplets;
With
The functional material coating apparatus is characterized in that an object to be coated is arranged in a non-contact manner inside the annular coating liquid discharge head, and the coating liquid is applied to an outer peripheral surface of the object to be coated.

The invention according to claim 2
The functional material coating apparatus according to claim 1, wherein the droplet forming unit is a vibration applying unit that applies a vibration to the coating liquid supplied to the coating liquid chamber.

The invention according to claim 3
The functional material coating apparatus according to claim 1, wherein the annular coating liquid chamber is endless.

The invention according to claim 4
An object driving means for rotating the object to be coated; and a head driving means for driving the annular coating liquid discharge head in the axial direction of the object to be coated;
The nozzle of the coating liquid discharge head while moving the outer peripheral surface of the coating object relative to the annular coating liquid discharge head by at least one of the coating object driving means and the head driving means. Discharge the coating liquid from
The functional material coating apparatus according to claim 1, wherein

The invention according to claim 5
2. The coating liquid is discharged from the nozzle so that a discharging direction of the coating liquid is inclined with respect to a line connecting the nozzle and a central axis of the annular coating liquid discharging head. This is a functional material coating apparatus.

The invention according to claim 6
6. The function according to claim 5, wherein a discharge direction of the coating liquid is directed to a direction in which an outer peripheral surface of the object to be coated moves relative to the axial direction with respect to the annular coating liquid discharge head. This is an adhesive material application device.

The invention according to claim 7 provides:
6. The function according to claim 5, wherein the discharge direction of the coating liquid is directed to a direction in which an outer peripheral surface of the coating object moves relative to the rotation direction with respect to the annular coating liquid discharge head. This is an adhesive material application device.

The invention according to claim 8 provides:
The functional material coating apparatus according to claim 1, wherein a plurality of the coating liquid discharge heads are arranged in the axial direction.

The invention according to claim 9 is:
The plurality of coating liquid ejection heads are coating liquid ejection heads that eject a coating liquid containing a functional material different from at least one of the plurality of coating liquid ejection heads from other coating liquid ejection heads. The functional material coating apparatus according to claim 8.

  According to the present invention, a good functional film is formed on the outer peripheral surface of a columnar or cylindrical article to be coated, which is excellent in ejection stability, and does not depend on the viscosity of the functional material coating solution, and the variation in film thickness is suppressed. It is possible to provide a functional material application apparatus and a functional material application method.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is provided to the member which has the substantially same function through all the drawings, and the overlapping description may be abbreviate | omitted.

  FIG. 1 is a perspective view showing a functional material coating apparatus according to an embodiment. FIG. 2 is a schematic configuration diagram illustrating a functional material coating apparatus according to the embodiment.

  As shown in FIGS. 1 and 2, the functional material coating apparatus 100 according to the first embodiment is an annular discharge for discharging a coating liquid 14 containing a functional material onto an object 10 on a mounting table 101. A head 12 (annular coating liquid discharge head), a coating liquid tank 16 for storing a coating liquid 14 to be fed to the annular discharge head 12, and an elevating device 18 (bed driving) that lifts and lowers the annular discharge head 12 in the axial direction. Means), a coating object driving device 20 for rotationally driving the coating object 10, and a liquid receiver 22 for receiving the coating liquid 14 discharged from the annular discharge head 12 when not coated. The arrow A is the moving direction of the annular discharge head 12, and the arrow B is the rotating direction of the article 10 to be coated.

  Further, a coating liquid supply pipe 24 is connected to the annular discharge head 12, and a coating liquid discharge pipe 26 is connected to the other end. One end side of the coating liquid supply pipe 24 and the coating liquid discharge pipe 26 (the side not connected to the annular discharge head 12) is connected to the coating liquid tank 16. A liquid supply pump 241 (pressurizing means: high-pressure arterial pump for solvent: triple plunger pump) is supplied to the coating liquid supply pipe 24 from the coating liquid tank 16 side toward the annular discharge head 12. A damper 242 that suppresses the pulsation of the pump 241, a filter 243 that removes foreign particles and the like of the coating liquid, and a liquid feeding electromagnetic valve 244 that starts and stops the feeding of the coating liquid 14 to the annular discharge head 12 are arranged. It is installed. On the other hand, a discharge electromagnetic valve 261 for starting / stopping discharge of the coating liquid 14 is disposed in the coating liquid discharge pipe 26.

  The discharge solenoid valve 261 is normally always closed and is opened when the coating liquid 14 is circulated, mixed air bubbles are removed, and the like.

  The object to be coated 10 is formed of a columnar shape or a cylindrical body, and is provided with shafts 102 extending coaxially at both ends in the axial direction so that the axis direction of the object to be coated 10 is perpendicular to the mounting table 101. And supported by two plate-like support members 103 so as to be rotated. In this way, the object to be coated 10 is disposed in a non-contact manner inside the annular discharge head 12.

  The workpiece drive device 20 includes a drive motor 201, a gear member 203 coupled to the drive motor 201 via a shaft 202, and a gear coupled to one shaft 102 (downward in the drawing) of the workpiece 10. A member 204 and a belt member 205 stretched between the two gear members 203 and 204 are configured. In the coating object driving device 20, the gear member 203 is rotationally driven by a drive motor, and the gear member 204 is rotationally driven together with the belt member 205 along with the rotation driving, and the coating object 10 rotates together with the shaft 102.

  The lifting device 18 is a lifting device using a ball screw, and is a plate-shaped guide member 181 provided perpendicular to the mounting table 101 (its main surface), and perpendicular to the guide member 181 (its main surface). A screw shaft 182 supported by two support members 103 fixed to each other and rotated by a motor (not shown), and a feed that moves in the longitudinal direction (vertical direction in the drawing) of the guide member 181 as the screw shaft 182 rotates. A member 183. Note that the guide member 181 and the screw shaft 182 are arranged in parallel to the axial direction of the workpiece 10.

  The feed member 183 of the elevating device 18 has a through hole 183A through which the screw shaft 182 passes, and a convex portion (not shown) fitted in the spiral groove of the screw shaft 182 on the inner wall thereof. Accordingly, the guide member 181 moves in the longitudinal direction (vertical direction in the figure).

  The plate-shaped guide member 181 of the lifting device 18 is provided with a groove 181A having a V-shaped cross section, and claw portions 183B provided at both ends in the width direction of the feed member 183 are formed in the groove 181A of the plate-shaped guide member 181. Has been inserted. As a result, the moving direction of the feed member 183 is regulated, and is guided and moved in the longitudinal direction (vertical direction in the drawing) of the plate-like guide member 181.

  The annular discharge head 12 is fixed to the feed member 183 via the arm 184, and moves in the longitudinal direction of the guide member 181 (vertical direction in the figure: axial direction of the coating object) in accordance with the movement of the feed member 183. Is done. Two arms 184 are provided (see FIG. 3), and the coating liquid supply pipe 24 and the coating liquid discharge pipe 26 may also be used, or the coating liquid supply may be provided inside the cylinder. The pipe 24 and the coating liquid discharge pipe 26 may be arranged inside.

  The liquid receiver 22 is disposed on one end side in the axial direction of the object to be coated 10 so as not to overlap the object to be coated 10. In the present embodiment, the liquid receiver 22 is disposed on the lower side (the mounting table 101 side) in the axial direction of the workpiece 10.

  The liquid receiver 22 is formed in an annular shape by bending a member having a concave section. Further, the inner wall portion of the liquid receiver 22 extends so as to protrude in the axial direction of the object to be coated. In the liquid receiver 22, the coating liquid 14 discharged from the annular discharge head 12 at the time of non-application is received by the extended inner wall portion and collected on the bottom surface of the member having a concave section. The liquid receiver 22 is connected to the coating liquid tank 16 and the filter 221 by a discharge pipe 222. When the discharged coating liquid 14 is received, it is discharged to the coating liquid tank 16.

  Hereinafter, the annular discharge head 12 will be described in detail. Here, FIG. 3 is a perspective view showing the annular discharge head according to the embodiment. FIG. 4 is a partial cross-sectional view of the annular discharge head according to the embodiment. FIG. 4 is a cross-sectional view cut in a direction orthogonal to the axial direction of the annular discharge head.

  As shown in FIGS. 3 to 4, the annular discharge head 12 is configured to have an annular shape by, for example, a cylindrical body 121 having a circular cross section (not limited to a circular shape but may be formed in a rectangular shape or other cross sections). Yes. The annular cylindrical body is endless. And the coating liquid chamber 122 is comprised by the hollow part of the cyclic | annular cylindrical body which comprises the cyclic | annular discharge head 12. FIG. That is, the annular coating liquid chamber 122 is configured to be annular and endless. The cylindrical body 121 is made of, for example, stainless steel or a nickel alloy. In FIG. 4, reference numeral 125 denotes a connecting portion (coating liquid inlet or outlet) of the arm 184 (the coating liquid supply pipe 24 or the coating liquid discharge pipe 26).

  Further, the annular discharge head 12 is provided with a plurality of nozzles 123 (for example, a nozzle inner diameter of 25 μm) along the circumferential direction in communication with the coating liquid chamber 122 on the inner peripheral side thereof, that is, through the coating liquid chamber 122. Yes. In addition, the annular discharge head 12 has a piezoelectric element 124 (droplet forming means: vibration applying means) facing the nozzles 123 through the coating liquid chamber 122 by a hollow portion of the annular cylindrical body 121 on the outer side thereof. Is provided. The piezoelectric elements 124 are not necessarily provided so as to face the nozzles 123 and may be disposed at a predetermined interval together with the nozzles 123.

  The annular discharge head 12 may be produced, for example, by curving a cylindrical body and joining both ends, or by stacking two circular semicircular recess members that are curved to form an annular shape. They may be produced by joining together. Although not shown, since all the electrical signals to the piezoelectric elements 124 may be common, it is sufficient that one signal wiring is arranged so as to be electrically connected to all the piezoelectric elements 124, and the head material is In the case of metal, one ground line may be connected to the head.

Here, the piezoelectric element 124 includes, for example, a PZT ceramic film and a polyvinylidene fluoride film (PVF ₂ film). The piezoelectric element 124 applies predetermined vibration (sound wave) to the coating liquid 14 sent to the coating liquid chamber 122 to make the coating liquid 14 discharged from the nozzle 123 into liquid droplets into droplets. belongs to. Although not shown, the piezoelectric element 124 generates a vibration (sound wave) by applying a high frequency voltage from an electrode to a PZT ceramic film, for example, and transmits this vibration to the coating liquid 14 in the coating liquid chamber 122 by a piston.

  The piezoelectric element 124 is provided to face the nozzle 123, for example, and is driven from the same direction as the discharge direction of the coating liquid 14 to be amplified by an external device (not shown) and output with a voltage up to, for example, a peak-to-peak voltage (Vpp) of about 50V. When a sine wave is supplied, vibration is applied by a standing wave (mixed wave of traveling wave and reflected wave: that is, a mixed wave of irradiated traveling wave and reflected wave reflected on the nozzle surface), and the nozzle The coating liquid 14 discharged in a liquid column form from 123 is formed into droplets.

  Here, FIGS. 5 to 7 show the discharge state of the coating liquid 14 having a viscosity of about 9 mPa · s. FIG. 5 is a schematic diagram showing a discharge state of the coating liquid 14 when no vibration is applied. FIG. 6 is a schematic diagram showing a discharge state of the coating liquid 14 when a vibration of 90 kHz is applied. FIG. 7 is a schematic diagram showing a discharge state of the coating liquid 14 when a vibration of 60 kHz is applied.

  For example, when the application liquid 14 is discharged from the annular discharge head 12 at 0.9 MPa by the liquid supply pump 241 without driving the piezoelectric element 124, the liquid columnar application liquid 14 is discharged as shown in FIG. Then, when vibration is applied to the coating liquid 14 by the piezoelectric element 124, the coating liquid 14 discharged in a liquid column shape is formed into droplets as shown in FIGS. As shown in FIGS. 6 and 7, when the vibration of 90 kHz is applied to the coating liquid 14, the droplet diameter of the coating liquid is smaller than when the 60 kHz vibration is applied to the coating liquid 14, and the inter-droplet distance ( (Droplet interval) is narrow. However, since the pump pressure is constant, the injection amount per unit time is the same.

  As shown in FIG. 5, when the coating liquid is applied in a liquid column state without being formed into droplets, a disordered jet is formed at a position away from the annular discharge head 12, so that the uniformity of the coating film (functional film) is achieved. Cannot be secured. Therefore, it is necessary to make the coating liquid 14 into droplets.

Here, for example, when the discharge speed of the coating liquid is 10 m / sec and the nozzle inner diameter is 25 μm, the preferred frequency is 88.7 kHz. The volume of the droplet is about 55 pl (pico liter) (55,000 μm ³ ). However, the frequency is not determined only from the viewpoint of droplet formation, and it is preferable to consider the vibration characteristics of the ejection head and the piezoelectric element. That is, it is preferable to adjust the voltage applied to the piezoelectric element 124 by considering the resonance point based on the structure of the ejection head and the characteristics of the piezoelectric element. For example, in the present embodiment, a voltage having a peak-to-peak voltage (Vpp) of about 30 V is applied to the piezoelectric element.

Note that the vibration frequency applied by the piezoelectric element 124 when the coating liquid 14 is made into droplets is, for example, the vibration characteristics of the piezoelectric element, the vibration characteristics of the annular discharge head 12, the speed of the coating liquid 14, the diameter of the nozzle 123, and the like. Determined by the correlation. For example, the fluid speed (discharge speed) of the coating liquid can be expressed by the relationship represented by the following formula.
Formula (1): Fluid velocity (μm / sec) = frequency (Hz) × particle interval (μm) (Velocity = fλ)
Also, according to “Rayleigh / Theory of Sound”, the most likely to form droplets (they are more likely to generate particles)
Formula (2): Particle spacing (μm) = 4.51 × Nozzle diameter (μm) (λ = 4.51 × d)
It is.
In addition, the volume of droplets (particles) into droplets is
Formula (3): Volume (μm ³ ) = Nozzle area (μm ² ) × Particle spacing (μm) (Volume = Aλ)
It becomes.

Here, for example, when the fluid velocity of the coating liquid 14 is 10 m / sec and the nozzle diameter is 25 μm, the preferred frequency is 88.7 kHz. The volume of the droplet is about 55 pl (pico liter) (55,000 μm ³ ). However, the frequency is not determined only from the viewpoint of droplet formation, and it is necessary to consider the vibration characteristics of the ejection head and the piezoelectric element. That is, it is preferable to adjust the voltage applied to the piezoelectric element by considering the resonance point based on the structure of the ejection head and the characteristics of the piezoelectric element. For example, in the present embodiment, a voltage having a peak-to-peak voltage (Vpp) of about 30 V is applied to the piezoelectric element.

  The pressure for discharging the coating liquid 14 having a viscosity of about 9 mPa · s at 10 m / sec is, for example, about 0.9 MPa. However, when discharging the coating liquid having a viscosity of about 3 mPa · s, for example, 0.3 MPa Experiments have shown that a degree of pressure is required. Therefore, in order to discharge a coating liquid having a viscosity of about 100 mPa · s, it is expected that a pressure of about 10 MPa, for example, is necessary. This is explained by the fact that the pressure applied to the coating liquid and the flow velocity have a linear relationship with the channel resistance as a coefficient. This is because the resistance value varies greatly depending on the shape of the nozzle 123. In addition, said numerical value is an example.

  Examples of the nozzle machining method generally include a punch machining method, an electroforming (electroforming) machining method, an electric discharge machining method, and a laser machining method. There are advantages and disadvantages to each processing method, and it is not possible to generally decide which method is preferable. However, when compared with a constant nozzle inner diameter, the cross-sectional shape of the nozzle is large from the viewpoint of the flow resistance of the nozzle. Tape forming electroforming is preferable from the viewpoint of keeping the injection pressure as low as possible.

  Further, the annular discharge head 12 may discharge the coating liquid 14 from the nozzle 123 so that the discharge direction of the coating liquid 14 is inclined with respect to a line connecting the nozzle 123 and the central axis of the annular discharge head 12. . Specifically, for example, as shown in FIG. 8A, the discharge direction of the coating liquid 14 is a direction in which the outer peripheral surface of the object to be coated 10 moves relative to the annular discharge head 12 in the axial direction. In this embodiment, as shown in FIG. 9A, the discharge direction of the coating liquid 14 is an annular shape (hereinafter referred to as a first discharge form) facing in the direction opposite to the moving direction of the annular discharge head 12. A form in which the outer peripheral surface of the object to be coated 10 moves relative to the discharge head 12 in the rotation direction (in this embodiment, the rotation direction of the object to be coated 10) (hereinafter referred to as a second discharge form). Is mentioned. In the figure, P indicates the discharge direction of the coating liquid 14, and Q indicates a line connecting the nozzle 123 and the central axis of the annular discharge head 12.

  In the case of the first discharge mode, as shown in FIG. 8B, for example, when the annular discharge head 12 is viewed from a cross section cut in parallel to the axial direction, the depth direction of the nozzle 123 is annular with the nozzle 123. This is realized by providing the nozzle 123 so as to be inclined with respect to a line connecting the central axis of the ejection head 12. Similarly, in the case of the second discharge mode, as shown in FIG. 9B, for example, when the annular discharge head 12 is viewed from a cross section cut perpendicular to the axial direction, the depth direction of the nozzle 123 is the nozzle direction. This is realized by providing the nozzle 123 so as to be inclined with respect to a line connecting 123 and the central axis of the annular discharge head 12. In the case of FIG. 8, the charging and deflection control is performed by the charging electrode and the deflection electrode arranged on the coating liquid discharge surface side (nozzle surface) side of the annular discharge head 12 to be described later to change the discharge direction of the coating liquid. May be.

  When the discharge direction of the coating liquid 14 is inclined, the normal direction of the landing surface where the discharged coating liquid 14 lands on the object 10 (indicated by R in the figure) and the discharge direction of the coating liquid (indicated by P in the figure). And an angle (acute angle: θ), and a droplet of the coating liquid 14 reaches the object 10 (see FIGS. 8 and 9). Note that the normal line of the landing surface is a tangent to the landing position (in the figure, when the landing surface of the object to be coated is a curved surface (for example, when the object to be coated is a cylinder or a column). , And a line perpendicular to the plane formed by S).

  When the normal direction of the landing surface on which the coating liquid 14 to be ejected lands on the workpiece 10 and the ejection direction of the coating liquid 14 make an angle, and the coating liquid 14 lands on the coating 10, the coating liquid immediately after ejection The landing speed of the coating liquid 14 along the normal direction on the landing surface of the object 10 is slower than the discharging speed 14 (discharge speed along the discharging direction). In other words, it is presumed that the landing impact of the coating liquid is mitigated because the landing speed is dispersed in the normal direction of the landing surface and the direction parallel to the landing surface while having a discharge speed capable of maintaining discharge stability. The

  Here, FIGS. 10 and 11 schematically show the landing model of the droplet of the coating liquid 14. FIG. 10 shows, for comparison, how a droplet of the coating liquid 14 lands on a landing surface (in the drawing, the surface of the liquid layer as the object 10 to be coated) from the normal direction of the surface. Show. On the other hand, in FIG. 11, a droplet of the coating liquid 14 lands on the landing surface (in the figure, the surface of the liquid layer as the object to be coated 10) having an angle with the normal direction of the surface. Show the state.

  As shown in FIG. 10, when the landing surface (liquid surface) is driven at a high speed from the normal direction of the landing surface, the rebound will fly. Further, when the liquid surface is greatly dented, bubbles are entrained in the liquid layer and cured as it is, the bubbles are trapped in the film. In the case of a multilayer film, it becomes turbid with the lower layer. On the other hand, as shown in FIG. 11, when the droplet of the coating liquid 14 lands on the landing surface at an angle with the normal direction of the surface, the landing speed along the normal direction of the landing surface decreases. No bounce occurs.

  An annular discharge head so that the normal direction of the landing surface on which the coating liquid 14 to be ejected lands on the object to be coated 10 and the ejection direction of the coating liquid 14 form an angle so that the coating liquid 14 lands on the object to be coated 10. 12 can reduce the rebound of the landed coating liquid 14 while maintaining the discharge stability, and can prevent unevenness of the formed coating film (functional film), for example, if the landing surface is another coating film. Even when it is configured, the other coating film is prevented from being disturbed.

  Further, the discharge direction of the coating liquid 14 is directed to the direction in which the outer peripheral surface of the coating object 10 moves relative to the annular discharge head 12 in the axial direction, and the discharge direction of the coating liquid 14 is set to the annular discharge head 12. When the discharge direction of the coating liquid 14 is directed in the direction of movement of the outer peripheral surface of the object 10 as in the form in which the outer peripheral surface of the object 10 is moved in the direction of relative movement in the rotation direction, When the liquid 14 has landed on the object 10 to be coated, the relative speed with respect to the landing surface in the direction parallel to the landing surface, that is, the landing speed along the tangential direction of the landing surface (point) (hereinafter referred to as tangential relative speed). In some cases) and the impact impact of the coating liquid in the tangential direction is reduced. For this reason, the rebound of the landing coating liquid 14 can be reduced more effectively, preventing the nonuniformity of the formed coating film and, for example, even when the landing surface is composed of another coating film, Disturbance is suppressed.

  Although not shown, the annular discharge head 12 has a pair of charging electrodes for charging the discharged coating liquid 14 on the nozzle surface side, and an electric field is applied to the charged coating liquid 14 to apply deflection to change the discharge direction. A pair of deflection electrodes may be provided. When a pair of charging electrodes and a pair of deflection electrodes are provided to control charging / deflection of droplets of the coating liquid 14, the ejection direction can be controlled, the coating amount can be limited, and a pattern can be applied to the coating.

  Hereinafter, the coating operation of the functional material coating apparatus according to the present embodiment will be described.

  First, the liquid discharge pump 241 is driven in a state where the annular discharge head 12 is disposed so that the nozzle surface faces the liquid receiver 22 disposed on the lower side in the axial direction (mounting table 101 side) of the object to be coated. At the same time, the electromagnetic valve for liquid delivery 244 is opened. In addition, the piezoelectric element 124 is driven. As a result, the liquid columnar coating liquid 14 is discharged from the nozzle 123 and the liquid columnar coating liquid 14 is made into droplets. At this time, the coating liquid 14 discharged from the annular discharge head 12 is received by the liquid receiver 22. This is performed until the droplets of the coating liquid 14 are stabilized.

  Next, the coating object driving device 20 is driven to rotate the coating object 10 (for example, the rotation speed of the coating object 10 is set to 1 rotation / 1 second (1 rps)).

  Next, the lifting / lowering device 18 is driven to raise the annular discharge head 12. At this time, the annular discharge head 12 is raised coaxially with the axis of the object to be coated 10, that is, translated in the axial direction of the object to be coated 10. The annular discharge head 12 is raised, the nozzle surface thereof is opposed to the outer peripheral surface of one axial end portion of the article 10 to be coated, and the droplet of the coating liquid 14 to be discharged is landed on the outer peripheral surface. Thereby, application | coating is started.

  Then, after the annular discharge head 12 reaches the position facing the outer peripheral surface of the other end in the axial direction of the workpiece 10, the driving of the liquid feeding pump 241 and the piezoelectric element 124 is stopped, and the liquid feeding electromagnetic valve When 244 is closed, the discharge of the coating liquid 14 is stopped and the coating is finished. After the application is completed, the rotation of the object to be coated 10 is stopped and the annular discharge head 12 is lowered to reach the position where the nozzle surface faces the liquid receiver 22.

  After the annular discharge head 12 reaches the position facing the outer peripheral surface of the other end in the axial direction of the object to be coated 10, it is lowered and returned to the position facing the outer peripheral surface of the other end in the axial direction of the object to be coated. Application may be terminated. Of course, this operation may be repeated.

  Here, the control of the total thickness of the coating film by the coating liquid 14 can be carried out by repeatedly performing the above operation. However, when it is desired to have a thickness distribution along the axial direction of the article 10 to be coated, It is preferable to control the raising / lowering speed of the discharge head 12 (relative movement speed with respect to the coating object 10).

  Specifically, for example, as shown in FIG. 12, the lifting speed of the annular discharge head 12 (indicated by the moving speed in the figure) is higher than the area facing the outer peripheral surface of both ends in the axial direction of the workpiece 10. When the speed is increased in a region facing the outer peripheral surface in the axial center portion, the coating film formed on the outer peripheral surfaces in both axial ends of the workpiece 10 is formed thicker than the coating film formed on the outer peripheral surface in the axial center portion. The At this time, the thickness of the coating film in the circumferential direction (rotation direction) of the object to be coated 10 is constant because the rotation speed of the object to be coated 10 does not change. Of course, this is only an example, and the lifting speed of the annular discharge head 12 may be controlled to a relationship opposite to the above-described relationship according to the request, or a plurality of regions may be disposed in the region facing the outer peripheral surface of the workpiece 10. You may control to the speed of.

  As shown in FIG. 12, when the elevation speed of the annular discharge head 12 is increased, the thickness of the coating film tends not to be thin, and when it is slowed, the thickness of the coating film tends not to increase. It can be seen that the thickness of the coating film can be controlled by controlling. FIG. 12 is a relationship diagram illustrating an example of the relationship between the elevation speed of the annular discharge head 12, the application position of the coating object 10, and the thickness of the coating film.

  In addition, by continuing the rotation of the coating object for a predetermined time after the coating is completed, it is possible to prevent the coating film from dripping in addition to smoothing the coating film. The landing of the coating liquid 14 on the surface of the article 10 to be coated does not necessarily cover the entire surface, and there may be a gap between the landed droplets. For this reason, after landing on the surface of the object 10 to be coated, the coating liquid 14 is present in a shape close to a hemisphere reflecting the shape of the droplet as the viscosity increases. For this reason, in order to form a uniform coating film, it is important to manage the time in the smoothing step by rotating the article to be coated 10 after coating. Further, when the coating film is smoothed while rotating the object to be coated 10, the centrifugal force causes the coating liquid 14 to work in a direction to protect the convex shape with respect to the object to be coated 10. It is desirable to reduce it to such an extent that no one will occur. The coating liquid 14 spreads due to the affinity with the surface of the object 10 to be coated, and the coating film is flattened while attracting adjacent landing droplets with the rotation time of the object 10 to be coated.

  In the functional material coating apparatus 100 according to the present embodiment described above, the functional material coating liquid 14 is continuously pressurized, the liquid columnar coating liquid 14 is ejected from the nozzle 123, and the ejected liquid columnar coating liquid 14 is ejected. The coating liquid 14 is formed into droplets and applied to the article 10 to be coated. In this way, since the coating liquid 14 is discharged under continuous pressure, even a high-viscosity coating liquid (for example, a coating having a viscosity of about 3 mPa · s or less close to water to a coating having a viscosity of about 300 mPa · s) is stable. Then, the coating liquid 14 can be discharged and applied to the article 10 to be coated.

  In addition, since the coating liquid chamber 122 of the annular discharge head 12 is formed in an annular shape, even when the annular discharge head 12 vibrates, the degree of vibration between the portions is reduced as compared with the linear discharge head. Therefore, the variation in the thickness of the coating film (functional film) to be formed is reduced. Further, since the annular discharge head 12 can position the application start position and the application end position on the outer peripheral surface of the axial end portion of the application object, the application start due to the difference in the degree of volatilization of the solvent of the application liquid. The region where the coating unevenness occurs at the time and at the end of coating is limited to the outer peripheral surface of the axial end portion of the workpiece 10. For this reason, the area | region where the coating nonuniformity has arisen among coating films (functional film) can be utilized to the maximum.

  In the present embodiment, the piezoelectric element 124 applies a predetermined vibration (sound wave) to the coating liquid 14 sent to the coating liquid chamber 122, and the coating liquid 14 discharged in a liquid column shape from the nozzle 123. It has become droplets. On the other hand, it is preferable that vibration is evenly applied to the coating liquid 14 discharged from the nozzle 123. In this regard, in the case of an ejection head constituted by a straight pipe, the total sum of vibrations applied to the coating liquid ejected from the nozzle disposed at the longitudinal end portion and the nozzle disposed at the longitudinal center portion is different. . This is because the nozzle arranged at the center part is not only opposed to the piezoelectric element but also vibrated from the piezoelectric elements at both ends in the head longitudinal direction, whereas the nozzle arranged at one end part in the head longitudinal direction is opposed. This is because only vibration from the piezoelectric element at one end in the longitudinal direction of the head is applied together with the piezoelectric element. For this reason, the application state of the discharged application liquid 14 changes.

  On the other hand, in this embodiment, since the annular discharge head 12 is configured to be endless, the nozzle 123 and the piezoelectric element 124 are arranged along the annular shape without any end portion, and at any position. The same total amount of vibration is evenly applied to the coating liquid 14 discharged from the nozzle 123. For example, as shown by a one-dot chain line as a representative line indicating a traveling direction of vibration (sound wave) transmitted between the piezoelectric element 124 and the nozzle 123, as shown in FIG. 4, from one nozzle 123 to each piezoelectric element 124. The relationship of the distance is the same for the other nozzles 123, and the sum of vibrations applied to the coating liquid 14 discharged from all the nozzles 123 is also the same. As a result, a coating film (functional film) is uniformly formed in the circumferential direction (rotation direction) of the workpiece.

  In addition, since the annular discharge head 12 is endless, there is no end, so even when the annular discharge head 12 vibrates, the degree of vibration is the same between the portions, and the thickness of the coating film Variation is reduced.

  In the present embodiment, the form in which the annular discharge head 12 is configured to be endless has been described. However, the present invention is not limited thereto, and may be endless. For example, as illustrated in FIG. An annular discharge head 12 may be employed. Here, FIG. 13 is a schematic perspective view showing another annular discharge head according to the embodiment.

  In the present embodiment, an embodiment in which one annular discharge head 12 is disposed has been described. However, the present invention is not limited to this, and a plurality of annular discharge heads 12 may be disposed in the axial direction as shown in FIG. Good (in the figure, three annular discharge heads are provided). At this time, in the plurality of annular discharge heads, the arrangement positions of the nozzles 123 may be shifted from each other in the head circumferential direction (the circumferential direction of the object to be coated 10). Here, in FIG. 14, T indicates a shift in the position of the nozzle 123 on the head. As a result, the landing position of the coating liquid 14 ejected by each annular ejection head 12 is shifted, so that a coating film with more uniform and reduced variation in film thickness can be obtained.

  When a plurality of annular discharge heads 12 are provided, at least one of the annular discharge heads 12 is preferably an annular discharge head 12 that discharges a coating liquid 14 containing a functional material different from the other annular discharge heads 12. Thus, in the case of discharging the coating liquid 14 containing different functional materials from the plurality of annular discharge heads 12, for example, as shown in FIG. When the droplet of the coating liquid 14 </ b> A is ejected from the annular ejection head 12, the droplet is applied onto a predetermined area of the object to be coated 10. Next, as shown in FIG. 15 (B), coating is performed from another annular discharge head 12 on a predetermined region of the object 10 (region other than the region where the coating liquid 14A is landed by the annular discharge head 12). When droplets of the coating liquid 14B of a material type different from the liquid 14A are ejected, the droplets are applied onto a predetermined region of the article 10 to be coated. Then, as shown in FIG. 15C, coating solutions 14A and 14B are respectively applied to predetermined regions, and a functional material film made of a different material is patterned. Here, FIG. 15 is a process diagram illustrating an example of a process of forming a coating film by the functional coating apparatus according to the embodiment.

  As described above, the functional material coating apparatus 100 according to the embodiment is a continuous coating apparatus that discharges while continuously pressurizing the coating liquid, but is a drop that intermittently ejects droplets of the coating liquid by a so-called piezoelectric element. Compared to an on-demand (DOD) type coating apparatus, the continuous type sprays constantly, so drying at the nozzle is not a problem. This is one of the reasons why the continuous type is suitable as the functional material coating apparatus. Functional materials often use organic solvents in the coating solution state, and are often highly volatile. With the DOD type, clogging occurs immediately after a pause, etc., and device stability is obtained. I can't.

  Another point that the continuous type coating apparatus is superior to the DOD type coating apparatus is that it can easily cope with liquids having high viscosity and different viscosities. That is, in piezoelectric vibration or rapid boiling (Thermal Ink Jet) used for the DOD type, the liquid viscosity is approximately 10 mPa · s, and it is difficult to eject a high-viscosity liquid higher than that. However, in the case of the continuous type, since discharge of the coating liquid depends on the pump pressure, there is basically no restriction on viscosity by selecting a suitable pump.

  Moreover, in the film formation of a functional material, it is fully conceivable that a plurality of materials are applied. In the DOD type coating device, it is necessary to optimally design the flow path structure centered on a piezo or a heater according to the viscosity of the jet liquid. In the case of a continuous type coating device, if the pump pressure is adjusted, a different viscosity can be obtained. It is possible to discharge the coating liquid without changing the configuration of the discharge head or the like. Therefore, the device design is simple and the degree of freedom in selecting the functional liquid is extremely high. This is also a major reason why the continuous type is suitable.

  In any of the embodiments, the form in which the piezoelectric element is applied as the coating liquid droplet forming means has been described. However, the present invention is not limited to this, and a system in which the coating liquid is heated and droplets are formed by the fluctuation of the heat may be used. Alternatively, a method of forming droplets using electrostatic attraction may be used.

  In addition, the functional material coating apparatus according to the present embodiment is appropriately used for electrophotographic members (electrophotographic photoreceptors, functional belts (intermediate transfer bodies), transfer rolls, charging rolls, etc.) and other industrial products. be able to. Therefore, the functional material is selected according to the characteristics required for various materials applied to them. And the coating liquid 14 containing this functional material is normally comprised by mixing a functional material with a solvent, but may be comprised only with a functional material.

It is a perspective view which shows the functional material application apparatus which concerns on embodiment. It is a schematic block diagram which shows the functional material coating device which concerns on embodiment. It is a perspective view showing the annular discharge head concerning an embodiment. It is a fragmentary sectional view of the annular discharge head concerning an embodiment. It is a schematic diagram which shows the discharge state of the coating liquid 14 when not giving a vibration. It is a schematic diagram which shows the discharge state of the coating liquid 14 when a 90 kHz vibration is provided. It is a schematic diagram which shows the discharge state of the coating liquid 14 when a 60 kHz vibration is provided. It is a schematic diagram for demonstrating an example of the discharge direction of the coating liquid of the annular discharge head which concerns on embodiment. It is a schematic diagram for demonstrating the other example of the discharge direction of the coating liquid of the cyclic | annular discharge head which concerns on embodiment. It is a schematic diagram which shows the landing model of the droplet of the coating liquid 14 which concerns on a comparative example. It is a schematic diagram which shows the landing model of the droplet of the coating liquid 14 which concerns on embodiment. FIG. 5 is a relationship diagram illustrating an example of a relationship between a lifting speed of an annular discharge head 12, a coating position of an object to be coated 10, and a thickness of a coating film. It is a schematic perspective view which shows the other annular discharge head which concerns on embodiment. It is a schematic perspective view which shows the other annular discharge head which concerns on embodiment. It is process drawing which shows an example of the formation process of the coating film by the functional coating device which concerns on embodiment.

Explanation of symbols

10 Object 12 Annular Discharge Head (Coating Liquid Discharge Means)
14 (14A, 14B) Coating liquid 16 Coating liquid tank 18 Lifting device (head driving means)
20 object driving device (object driving means)
22 Liquid receiver 22
24 coating liquid supply pipe 26 coating liquid discharge pipe 100 functional material coating apparatus 101 mounting table 102 shaft 103 support member 121 cylindrical body 122 coating liquid chamber 123 nozzle 124 piezoelectric element (droplet forming means: vibration applying means)
181 Guide member 181A Groove 182 Screw shaft 183 Feed member 183A Through port 183B Claw 184 Arm 201 Drive motor 202 Shaft 203, 204 Gear member 205 Belt member 221 Filter 222 Discharge pipe 241 Liquid feed pump 242 Damper 243 Filter 244 Liquid feed Solenoid valve 261 Discharge solenoid valve

Claims (9)

An annular coating liquid chamber to which a coating liquid containing a functional material is supplied, and a nozzle that communicates with the annular coating liquid chamber and is disposed on the inner peripheral side of the annular coating liquid chamber to discharge the coating liquid An annular coating liquid discharge head having
Pressurizing means for continuously pressurizing and supplying the coating liquid to the coating liquid chamber, and discharging the coating liquid in a liquid column shape from the nozzle;
Droplet forming means for forming the coating liquid discharged from the nozzle in a liquid column shape into droplets;
With
A functional material coating apparatus, wherein a coating object is disposed in a non-contact manner inside the annular coating liquid discharge head, and the coating liquid is coated on an outer peripheral surface of the coating object.   The functional material coating apparatus according to claim 1, wherein the droplet forming unit is a vibration applying unit that applies a vibration to the coating liquid supplied to the coating liquid chamber.   The functional material coating apparatus according to claim 1, wherein the annular coating liquid chamber is endless. An object driving means for rotating the object to be coated; and a head driving means for driving the annular coating liquid discharge head in the axial direction of the object to be coated;
The nozzle of the coating liquid discharge head while moving the outer peripheral surface of the coating object relative to the annular coating liquid discharge head by at least one of the coating object driving means and the head driving means. Discharge the coating liquid from
The functional material coating apparatus according to claim 1.   2. The coating liquid is discharged from the nozzle so that a discharging direction of the coating liquid is inclined with respect to a line connecting the nozzle and a central axis of the annular coating liquid discharging head. Functional material applicator.   6. The function according to claim 5, wherein a discharge direction of the coating liquid is directed to a direction in which an outer peripheral surface of the object to be coated moves relative to the axial direction with respect to the annular coating liquid discharge head. Material applicator.   6. The function according to claim 5, wherein a discharge direction of the coating liquid is directed to a direction in which an outer peripheral surface of the coating object moves relative to the rotation direction with respect to the annular coating liquid discharge head. Material applicator.   The functional material coating apparatus according to claim 1, wherein a plurality of the coating liquid discharge heads are arranged in the axial direction.   9. The function according to claim 8, wherein at least one of the plurality of coating liquid ejection heads is a coating liquid ejection head that ejects a coating liquid containing a functional material different from other coating liquid ejection heads. Material applicator.

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