KR20230170184A - Inkjet print device - Google Patents

Abstract

An inkjet printing device is provided. The inkjet printing device includes a print head including a nozzle that discharges ink on a substrate, a reservoir that stores ink, a manifold that receives ink from the reservoir, and a damper that provides a movement path for ink between the manifold and the nozzle. An ink supply unit and a first pipe providing a path of ink from the reservoir to the manifold, wherein at least one of the print head, the ink supply unit, and the first pipe changes the charging state of the print head, the ink supply unit, or the first pipe. It includes a charging unit, and further includes a power supply unit that applies voltage to the charging unit.

Description

Inkjet print device {INKJET PRINT DEVICE}

The present invention relates to an inkjet printing device.

As the information society develops, the demand for display devices for displaying images is increasing in various forms. For example, display devices are applied to various electronic devices such as smartphones, tablet PCs, digital cameras, laptop computers, navigation, monitors, and TVs. Display devices include liquid crystal display devices, field emission display devices, organic light emitting display devices, quantum dot light emitting display devices, etc. It may be a flat panel display device.

Among these, an inkjet printing process, which forms a thin film of a desired shape by spraying ink onto the surface of an object, may be used in a thin film manufacturing process such as forming a light emitting layer of an organic light emitting display device. The inkjet printing device can print a thin film with a desired pattern on the substrate by generating individual ink droplets from a nozzle of the print head and discharging them at a predetermined location on the substrate, which is an object.

The inkjet print device is a discontinuous inkjet printing method that generates ink droplets from the print head when necessary, and ink droplets are continuously generated from the print head, and only selected ink droplets are ejected toward the substrate, and ink droplets that are not ejected are discharged to the ink supply unit. It can have a recirculated continuous inkjet printing method.

The problem to be solved by the present invention is to prevent ink from settling within an inkjet printing device with a simple structure.

The problems of the present invention are not limited to the problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below.

An inkjet printing device according to an embodiment for solving the above problem includes a print head including a nozzle for ejecting ink on a substrate, a reservoir for storing the ink, a manifold for receiving the ink from the reservoir, and the manifold. and an ink supply unit including a damper that provides a movement path of the ink between the nozzles, and a first pipe that provides a path of the ink from the reservoir to the manifold, including the print head and the ink supply unit. and at least one of the first pipes includes a charging unit that changes the charging state of the print head, the ink supply unit, or the first pipe, and a power supply unit that applies a voltage to the charging unit.

The reservoir may include a reservoir charging unit that receives voltage from the power supply unit.

The reservoir charging portion may directly contact the ink stored in the reservoir.

It further includes a second pipe that provides a path for remaining ink from the print head to the reservoir, and the second pipe includes a second pipe charging unit that receives voltage from the power supply and changes the charging state of the second pipe. can do.

It further includes a pump disposed in the second pipe and pressurizing the remaining ink and supplying it to the reservoir, wherein the pump may include a pump charging unit that receives voltage from the power supply unit and changes the charging state of the pump. .

The magnitude of the voltage applied to the charging unit by the power supply unit may vary depending on the arrangement of the charging unit.

The first pipe may include a first pipe electrifying portion that changes the charging state of the first pipe, and the first pipe electrifying portion and the second pipe electrifying portion may include a conductive material.

The power unit includes a direct current power source, the print head includes a head charging unit that changes the charging state of the print head, and the first pipe includes a first pipe charging unit that changes the charging state of the first pipe. , the voltage applied by the power unit to the head charging unit or the first pipe charging unit may be the same as the polarity at which the ink is charged.

The level of voltage applied by the power unit to the head charging unit may be different from the voltage applied to the first pipe charging unit.

The first pipe includes a first pipe charging unit that changes the charging state of the first pipe, and when the power unit is turned on to apply a voltage to the first pipe charging unit, the first pipe charging unit is connected to the first pipe. A repulsive force can be applied to the ink inside.

The first pipe is made of Teflon and includes a first pipe charging unit that changes the charging state of the first pipe, and the power supply unit can apply a positive voltage to the first pipe charging unit.

An inkjet printing device according to another embodiment for solving the above problem includes a reservoir that stores ink charged to a first polarity and includes a reservoir charging portion charged to the first polarity, a nozzle that discharges the ink onto a substrate, and the A print head including a head charging unit charged to a first polarity, a manifold receiving ink from the reservoir, a damper providing a movement path for the ink between the manifold and the nozzle, and ink charged to the first polarity. an ink supply unit including a supply unit charging unit, a first pipe providing a path for the ink from the reservoir to the print head and charged to the first polarity, including a charging unit, and remaining ink from the print head to the reservoir. and a second pipe that provides a path and includes a second pipe charging portion charged to the first polarity.

The head charging unit, the first pipe charging unit, the second pipe charging unit, the ink supply charging unit, and the reservoir charging unit may be in direct contact with the ink.

The head charging unit, the first pipe charging unit, the second pipe charging unit, the ink supply charging unit, and the reservoir charging unit may be charged by corona discharge.

The head charging unit, the first pipe charging unit, the second pipe charging unit, the ink supply charging unit, and the reservoir charging unit may be charged by friction charging.

The inkjet printing device includes the head charging unit, the first pipe charging unit, the second pipe charging unit, the ink supply charging unit, and the reservoir charging unit including a conductive material, and opposing the ink with the head charging unit interposed therebetween. a head insulating portion disposed in a direction opposite to the ink with the first pipe charging portion interposed therebetween, a first pipe insulating portion disposed in a direction opposite to the ink with the second pipe charging portion interposed therebetween; It may further include a pipe insulating part, an ink supply insulating part disposed in a direction opposite to the ink with the ink supply charging part in between, and a reservoir insulating part disposed in a direction opposite to the ink with the reservoir charging part in between.

The head insulator electrically separates the head charging unit, the first pipe insulator electrically separates the first pipe charger, the second pipe insulator electrically separates the second pipe charger, and the ink supply unit. The insulating part may electrically separate the ink supply part, and the reservoir insulating part may electrically separate the reservoir charging part.

The first pipe includes a first flow pipe that contacts the ink and serves as a passage for the ink, and the first pipe charging portion may be arranged to be spaced apart from the first flow pipe.

Due to electromagnetic induction by the first pipe charging unit, the outer wall of the first flow pipe may have a second polarity different from the first polarity, and the inner wall of the first flow pipe may have the first polarity.

The inner wall of the first flow pipe and the ink may apply a repulsive force to each other.

According to the inkjet printing device according to the embodiments, the polarity of the internal structure of the inkjet printing device is charged to the same polarity as the polarity of the ink, thereby preventing the problem of charged ink settling within the inkjet printing device.

Effects according to the embodiments are not limited to the contents exemplified above, and further various effects are included in the present specification.

1 is a schematic perspective view to explain an inkjet printing device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the substrate cut along line II' of FIG. 1.
Figure 3 is a diagram for explaining an inkjet printing device according to an embodiment of the present invention.
Figure 4 is a top view of a print head according to an embodiment of the present invention.
Figure 5 is a cross-sectional view of the print head taken along line II-II' in Figure 4.
Figure 6 is a perspective view of a reservoir according to an embodiment of the present invention.
Figure 7 is a cross-sectional view of the reservoir shown in Figure 6.
Figure 8 is a cross-sectional view for explaining a mixing unit according to an embodiment of the present invention.
9 is a schematic diagram of a first pipe according to one embodiment.
Figure 10 is a cross-sectional view of a first pipe according to one embodiment.
11 is a schematic diagram of a first pipe according to another embodiment.
Figure 12 is a schematic diagram of a first pipe according to another embodiment.
13 and 14 are schematic diagrams of a first pipe according to another embodiment.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. The present embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is not limited. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

When an element or layer is referred to as “on” another element or layer, it includes instances where the element or layer is directly on top of or intervening with the other element. Like reference numerals refer to like elements throughout the specification.

Although first, second, etc. are used to describe various components, these components are of course not limited by these terms. These terms are merely used to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may also be a second component within the technical spirit of the present invention.

Hereinafter, specific embodiments will be described with reference to the attached drawings.

1 is a schematic perspective view to explain an inkjet printing device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the substrate cut along line II' of FIG. 1.

Referring to Figures 1 and 2, the inkjet print device 1 according to an embodiment of the present invention includes a stage 10 and a print head that ejects ink (for example, organic light-emitting ink) on a substrate 30. It may include 200 and a driving unit (not shown) that moves the stage 10 or the print head 200.

The stage 10 supports the substrate 30 and may be made of a rigid material. However, the material of the stage 10 is not limited to this. In an exemplary embodiment, the stage 10 may have a rectangular parallelepiped shape, but the shape of the stage 10 is not limited thereto.

A substrate 30 may be placed on the stage 10. The substrate 30 may include a base substrate, a thin film transistor, and an insulating layer. The base substrate may be made of a material such as transparent glass, plastic sheet, or silicon, but the material of the base substrate is not limited thereto.

The substrate 30 may be a unit display substrate or a mother substrate before being cut and divided into a plurality of unit display substrates. The substrate 30 may be a single substrate 30, but may also include a plurality of stacked substrates.

As shown in FIG. 2, the substrate 30 according to an embodiment of the present invention has a buffer layer 33 formed on a base substrate 30a, and a thin film transistor 31 and an organic A light emitting element 32 may be formed.

The thin film transistor 31 may have an active layer 31a, a gate insulating film 34 formed to cover the active layer 31a, and a gate electrode 31b on the gate insulating film 34.

An interlayer insulating film 35 may be formed to cover the gate electrode 31b, and a source electrode 31c and a drain electrode 31d may be formed on top of the interlayer insulating film 35.

The source electrode 31c and the drain electrode 31d may be in contact with the source region and drain region of the active layer 31a, respectively, through contact holes formed in the gate insulating film 34 and the interlayer insulating film 35.

Also, the pixel electrode 32a of the organic light emitting device 32 may be connected to the drain electrode 31d. The pixel electrode 32a is formed on the planarization film 36, and a pixel defining layer (37) is formed on the pixel electrode 32a to partition the sub-pixel area. Then, the light-emitting layer 32b of the organic light-emitting device 32 is formed in the opening of the pixel definition film 37, and the counter electrode 32c is deposited on top of the light-emitting layer 32b. That is, the opening surrounded by the pixel defining film 37 becomes the area of one sub-pixel, such as the red pixel (R), green pixel (G), and blue pixel (B), and the light emitting layer 32b of the corresponding color is therein. It is formed. Here, one sub-pixel is shown, and in the actual display unit, multiple such sub-pixels may be arranged in the row and column directions.

The plurality of sub-pixels may have a rectangular shape. A plurality of sub-pixels may be arranged in a matrix of n times m (where n and m are integers of 1 or more). In the exemplary embodiment shown in FIG. 1 , when the row direction is the y direction and the column direction is the x direction, subpixels may be arranged in a matrix of 6 times 6 on the substrate 30 . However, the sub-pixel arrangement of FIG. 1 is an example, and in reality, a larger number of sub-pixels may be arranged on the substrate 30. Additionally, sub-pixels may be arranged in various forms such as a stripe form or a pantile form as well as a matrix form.

Thin films of such an organic light emitting display device can be formed by printing with the above-described print head 200. For example, by spraying ink at a position corresponding to the light emitting layer 32b, the light emitting layer 32b with a desired pattern can be formed. .

Figure 3 is a diagram for explaining an inkjet printing device according to an embodiment of the present invention. Figure 4 is a top view of a print head according to an embodiment of the present invention. Figure 5 is a cross-sectional view of the print head taken along line II-II' in Figure 4. Figure 6 is a perspective view of a reservoir according to an embodiment of the present invention. Figure 7 is a cross-sectional view of the reservoir shown in Figure 6. Figure 8 is a cross-sectional view for explaining a mixing unit according to an embodiment of the present invention.

3 to 8, the inkjet printing device 1 includes an ink supply unit 60, a print head 200, a reservoir 40, a first pipe P1, and a second pipe P2. ), a mixing unit 50, a pump (PU), a temperature sensor (TS), a control unit 70, and a power supply unit 700.

According to one embodiment of the present invention, the print head 200 may eject ink onto the substrate 30.

Print heads can be divided into several types depending on the ink discharge method. One of them is a heat-driven print head that uses a heat source to generate bubbles in the ink and discharges the ink by the expansion force of the bubble, and the other uses a piezoelectric material to ink the ink due to the deformation of the piezoelectric material. It is a piezoelectric print head that ejects ink by applying pressure. Hereinafter, the inkjet printing device 1 is described on the assumption that it includes a piezoelectric print head, but is not limited thereto.

Referring to Figures 4 and 5, the print head includes a flow path plate 220 with an ink flow path, a nozzle plate 230 with a plurality of nozzles 232 through which ink is ejected, and a plurality of piezoelectric actuators 240. Includes.

A silicon substrate may be used as the flow path plate 220 and the nozzle plate 230. A manifold 221, a plurality of restrictors 223, and a plurality of pressure chambers 222 are formed on the flow path plate 220. The manifold 221 is a passage through which ink flows from the ink reservoir, and the pressure chambers 222 are filled with ink to be discharged, and may be arranged on one or both sides of the manifold 221. The restrictor 223 is a passage connecting the manifold 221 and the pressure chambers 222. Meanwhile, a plurality of dampers 224 may be further formed between the nozzles 232 and the pressure chambers 222 to connect them. In addition, a plurality of piezoelectric actuators 240 are provided on the flow path plate 220 to correspond to each of the plurality of pressure chambers 222. The piezoelectric actuator 240 has a structure in which a lower electrode that serves as a common electrode, a piezoelectric film that deforms when a driving signal is applied, and an upper electrode that serves as a driving electrode are stacked. The flow path plate 220 located on the upper part of the pressure chambers 222 serves as a vibration plate 226 that is deformed by driving the piezoelectric actuator 240.

When a driving signal is applied to the piezoelectric actuator 240, the diaphragm 226 located at the top of the pressure chamber 222 is deformed and the volume of the pressure chamber 222 decreases, resulting in an increase in pressure within the pressure chamber 222. Ink is discharged to the outside through the nozzle 232. Subsequently, when the drive signal applied to the piezoelectric actuator 240 is removed, the volume of the pressure chamber 222 increases, and the pressure in the pressure chamber 222 decreases accordingly, causing the restrictor 223 to be removed from the manifold 221. Ink can be refilled into the pressure chamber 222 through.

The print head includes a head charging unit 250. The head charging unit 250 may be disposed to cover a portion in contact with ink within the print. More specifically, the head charging unit 250 may be arranged to cover the manifold 221, the restrictor 223, and the damper 224. The head charging unit 250 is connected to the power supply unit 700 so that voltage can be applied from the power supply unit 700. By adjusting the voltage applied from the power supply unit 700, the head charging unit 250 can be charged to + polarity or - polarity. The head charging unit 250 may be made of a conductor to receive voltage from the power supply unit 700.

The power supply unit 700 may apply a voltage of the same polarity as the polarity in which the ink is charged to the head charging unit 250. Accordingly, the head charging part 250 and the ink within the print head 200 have the same polarity, and the head charging part 250 applies a repulsive force to the ink, causing the ink to contact a specific part within the print head 200 and settle. You can prevent it from happening.

The reservoir 40 may store ink and supply ink to the print head 200 in response to a request from the print head 200.

Referring to FIGS. 6 and 7 , the reservoir 40 may include an ink tank 41 and a preheating unit 42 . For detailed explanation, the ink stored and flowing out of the reservoir 40 will be divided into new injected ink (INK0) and previously stored ink (INK1). The new injected ink (INK0) is ink stored in the external ink supply unit 60 and newly injected into the ink tank 41 through the injection port 41a, and the previously stored ink (INK1) is the new injected ink (INK0). This is ink stored in the ink tank 41 before being injected into the ink tank 41. Therefore, the temperature of the new injected ink (INK0) may be different from the temperature of the previously stored ink (INK1).

The ink tank 41 includes a storage area 41b for storing the previously stored ink (INK1), an injection port 41a through which new injected ink (INK0) is injected from the outside, and a storage area 41b for receiving the previously stored ink (INK1). It may include an outlet (OUT2) that discharges to the outside and a recovery port (IN2) that recovers ink that is not discharged from the nozzle 232 toward the substrate 30. The ink tank 41 may have an empty space of a certain volume so that the pre-stored ink (INK1) can be stored therein. The ink tank 41 may be made of a material with high thermal conductivity. It is preferably formed of a metal such as aluminum or aluminum alloy.

The injection port 41a is formed on the upper side of the preheating unit 42. Specifically, the injection port 41a is formed on the upper surface of the edge of the ink tank 41, and is connected to an external ink reservoir to receive new injection ink (INK0) from the ink reservoir into the inside.

In the storage area 41b, previously stored ink INK1 is temporarily stored in the storage area 41b of the ink tank 41. There is a level sensor (not shown) inside the reservoir 40, which recognizes the height of the previously stored ink (INK1), which has been lowered due to leakage, and injects new injected ink (INK0), thereby injecting a certain amount of new injected ink (INK0) and previously stored ink (INK1). The ink (INK1) can be kept stored in the storage area (41b). The storage area 41b is defined below the preheating unit 42. Accordingly, the pre-stored ink (INK1) is maintained to be stored only under the preheating unit (42).

The outlet OUT2 is formed on the lower side of the preheating unit 42. Specifically, it is formed on the lower side of the ink tank. However, it is not limited to this, and the outlet OUT2 may also be formed on the lower surface of the ink tank 41. The previously stored ink (INK1) in the storage area (41b) passes through the outlet (OUT2) and reaches the print head 200, and the previously stored ink (INK1) that has reached the print head 200 is discharged toward the substrate 30. It can be.

One side 41s of the ink tank 41 may be formed to be removable. If the inside of the reservoir 40 is contaminated or foreign matter is generated by using the reservoir 40 for a long period of time, the user can clean the inside of the reservoir 40 by removing the detachable side 41s. However, this is only an example, and the ink tank 41 may not include a detachable surface 41s.

The preheating unit 42 is disposed between the injection port 41a and the storage area 41b. The new injected ink (INK0) injected into the ink tank 41 from the injection port 41a may reach the preheating unit 42. One surface of the preheating unit 42 is in contact with the inner side of the ink tank 41 and can receive heat from the inner side.

The preheating unit 42 is made of a material with high thermal conductivity, and is preferably made of aluminum or aluminum alloy.

The preheating unit 42 may include a base plate BS having a flat plate shape. The base plate (BS) moves the new injection ink (INK0) injected from the injection port (41a) along the upper surface and transfers it to the storage area (41b). The preheating unit 42 includes a preheating wall (WA) formed along the edge of the base plate (BS) so that the new injected ink (INK0) is preheated while confined in the preheating unit (42) and transferred to the storage area (41b). can do. However, it is not limited to this and the shape of the preheating unit 42 may be modified. Specifically, the preheating unit 42 may include only the base plate BS and not the preheating wall WA.

The new injected ink (INK0) can move along the upper surface of the base plate (BS) to one end (BS_E) of the base plate (BS). New injection ink (INK0) injected through the injection port (41a) can reach the preheating unit (42). Since the preheating part 42 is in contact with the inner side of the ink tank 41, the preheating part 42 maintains thermal balance by receiving heat from the pre-stored ink (INK1) transferred to the inner side of the ink tank 41. It can be achieved.

Since the initial temperature of the new injected ink (INK0) is low and the density is high, the particles of the injected new injected ink (INK0) settle and spread within the preheating unit (42). The particles of the settled new injected ink (INK0) are heated by the preheating unit 42, thereby raising the temperature and lowering the density.

Particles of the new injected ink (INK0) whose temperature and density have reached a steady state float and diffuse to one end (BS_E) as shown by the first arrow (Da), and the new injected ink (INK0) diffused to one end (BS_E) It moves from one end (BS_E) of the base plate (BS) to the storage area (41b) and merges with the previously stored ink (INK1). The preheating wall (WA) at one end (BS_E) is formed lower than the other preheating walls (WA), so that the new injected ink (INK0) is formed at the preheating wall (WA) at one end (BS_E) as shown by the second arrow (Db). It is formed so that it can move beyond to the storage area (41b). However, the present invention is not limited thereto, and for example, the shape of the preheating wall WA at one end BS_E may be modified.

The initial temperature of the newly injected ink (INK0) injected into the ink tank 41 may be lower than the temperature of the previously stored ink (INK1), but the temperature of the previously stored ink (INK1) is increased by the preheating unit 42. Even after the new injected ink (INK0) is preheated to the same temperature and combined with the previously stored ink (INK1), the temperature of the ink in the storage area (41b) can be maintained uniformly. Accordingly, the viscosity of the pre-stored ink (INK1) stored in the reservoir 40 is maintained uniformly, so that a uniform amount of pre-stored ink (INK1) can flow out through the outlet (OUT2).

However, the reservoir 40 may not include the preheating unit 42 and may include only the storage area 41b.

The first pipe (P1) may connect the outlet (OUT2) of the reservoir 40 and the print head 200. Ink stored in the reservoir 40 may be supplied to the print head 200 via the first pipe (P1).

The second pipe (P2) may connect the print head 200 and the recovery port (IN2) of the reservoir 40. Remaining ink that is not ejected through the nozzle 232 of the print head 200 may be recovered to the reservoir 40 via the second pipe P2.

The reservoir 40 may include a reservoir charging unit 43. The reservoir charging portion 43 may be disposed on an area of the inner surface of the reservoir 40 that comes into contact with ink. The reservoir charging unit 43 is connected to the power supply unit 700 and can receive voltage from the power supply unit 700. The power supply unit 700 includes a direct current power source and can apply a voltage having a specific polarity to the reservoir charging unit 43. Accordingly, the reservoir charging portion 43 may have + or - polarity.

Ink particles (INK) move within the inkjet printing device 1 and may have a specific polarity through frictional charging. For example, if the inkjet printing device 1 includes a component containing a Teflon-based material, the ink particles (INK) may be frictionally charged to the component in the process of passing through the component and may be charged to the + pole. When the power supply unit 700 applies a positive voltage to the reservoir charging unit 43, the ink particles (INK) and the reservoir charging unit 43 have the same polarity, and the ink particles (INK) and the reservoir charging unit 43 have the same polarity. A repulsive force acts on each other to prevent ink particles (INK) from sticking to the inside of the reservoir 40. In other words, by applying a voltage of the same polarity as that of the ink particles (INK) to the reservoir charging unit 43 using the power supply unit 700, the problem of settling of the ink particles (INK) inside the reservoir 40 can be prevented. Although the inkjet printing device 1 includes a Teflon-based material and the ink particles (INK) are positively charged, the description is not limited thereto. For example, depending on the components included in the inkjet printing device 1, the ink particles (INK) may be charged to the -pole, and in this case, the power supply unit 700 applies a -pole voltage to the reservoir charging unit 43 to It is also possible to prevent the problem of sedimentation of ink particles (INK).

Although the reservoir charging unit 43 is shown in the drawing as covering the lower surface of the reservoir 40, the arrangement of the reservoir charging unit 43 is not limited to this. For example, the reservoir charging unit 43 may be arranged to cover only a portion of the lower surface of the reservoir 40, or may be placed on the side of the inner surface of the reservoir 40, and even the entire inner surface of the reservoir 40 is charged with the reservoir. It may also be composed of a unit 43.

The mixing unit 50 may be disposed in one area of the first pipe (P1). The mixing unit 50 may include a static mixer (SM) and a heater (H) that heats the ink.

The static mixer (SM) according to an embodiment of the present invention may include wings 52 arranged along the longitudinal direction of the mixing pipe body 51. As shown in FIG. 8, the wings 52 may include wing-elements 53 and 54 so that the ink can be transferred downward by changing its direction every pitch. The wing-elements 53 and 54 may have a screw shape, and the screw directions of the wing-elements 53 and 54 may be opposite to each other. However, the shape of the wing-elements 53 and 54 is not limited to this, and may be changed in various ways depending on the type and viscosity of the ink passing through the mixing unit 50. Additionally, the number of wing-elements 53 and 54 may be varied in response to the amount of ink passing through the mixing unit 50.

Ink may be injected into the static mixer SM through the first pipe P1. As the injected ink passes through the wings 52 installed in the longitudinal direction of the mixing tube 51, the wing-elements 53 and 54 change the feeding direction every pitch, so the particles and solvent contained in the ink change. They can be mixed evenly with each other. In particular, the generation of bubbles generated during the mixing process can be eliminated, thereby improving the physical efficiency of the ink.

The mixing unit may include a heater (H) surrounding the mixing tube 51 of the static mixer (SM).

The heater H according to one embodiment may be a silicone rubber heater. The heater H may include a heater mat 55 and a jacket 56.

The heater mat 55 can be attached in direct contact with the external surface of the mixing tube body 51. The heat generated by the heater mat 55 can be directly transferred to the mixing tube 51 mainly through conduction.

The jacket 56 extends radially outward from the heater mat 55 and substantially surrounds the heater mat 55, and may be an insulating material having a lower thermal conductivity than the mixing pipe body 51 and the heater mat 55. Since the jacket 56 has a lower thermal conductivity than the mixing pipe body 51, the heat generated by the heater mat 55 can mainly flow radially inward toward the mixing pipe body 51 rather than radially outward from the mixing pipe body 51. there is. Because of this, the heat of the heater H can be efficiently transferred to the ink passing through the mixing tube 51.

However, the type of heater H is not limited to this. For example, the heater H may be a device using the Peltier Effect.

The pump PU may be disposed in one area of the second pipe P2. For example, the pump PU may be disposed between the print head 200 and the cooling unit.

The pump PU can pressurize the remaining ink and supply it to the reservoir 40. When the reservoir 40 is disposed above the print head, the potential energy of the ink disposed within the print head may be smaller than the potential energy of the ink disposed inside the reservoir 40. Therefore, separate energy is required to move the ink placed in the print head into the reservoir 40, and the pump PU supplies energy by pressurizing the ink inside the print, thereby moving the ink inside the print into the reservoir 40. ) can be moved inside. The pump (PU) may be of various types known in the art.

The pump PU may include a pump charging unit PU1.

The pump PU may include a pump charging unit PU1. The pump charging unit PU1 may be disposed on an area in contact with ink on the inner surface of the pump PU. The pump charging unit PU1 is connected to the power supply unit 700 and can receive voltage from the power supply unit 700. The power supply unit 700 includes a direct current power source and can apply a voltage with a specific polarity to the pump charging unit PU1. Accordingly, the pump charging unit PU1 may have + or - polarity. The pump charging unit PU1 applies a repulsive force to the ink particles INK in the same manner as the reservoir charging unit 43 described above, thereby preventing the ink particles INK from settling within the pump PU.

The temperature sensor TS may be placed in one area of the first pipe P1. For example, the temperature sensor TS may be disposed between the mixing unit 50 and the printhead 20. The temperature sensor TS can detect the temperature of the ink that has passed through the mixing unit 50.

The control unit 70 may control the temperature of the heater H in response to information received from the temperature sensor TS.

For example, the control unit 70 may increase the temperature of the ink passing through the mixing unit 50 through the heater H in order to keep the amount of ink ejected from the print head 200 constant.

9 is a schematic diagram of a first pipe according to one embodiment. Figure 10 is a cross-sectional view of a first pipe according to one embodiment.

Referring to FIGS. 9 and 10 , the first pipe P1 may provide a passage through which ink moves. The first pipe (P1) has a long cylindrical shape, and ink can move from the reservoir 40 to the head via the mixing section through the internal space of the first pipe (P1). The first pipe (P1) includes a first pipe charging portion (P11). The first pipe charging unit P11 may be disposed to cover the movement path of ink within the first pipe P1. The first pipe charging unit (P11) is connected to the power supply unit 700 and can receive voltage from the power supply unit 700. The power supply unit 700 includes a direct current power source and can apply a voltage having a specific polarity to the first pipe charging unit P11. Accordingly, the first pipe charging portion (P11) may have + or - polarity.

Ink particles (INK) move within the inkjet printing device 1 and may have a specific polarity through frictional charging. For example, if the inkjet printing device 1 includes a component containing a Teflon-based material, the ink particles (INK) may be frictionally charged to the component in the process of passing through the component and may be charged to the + pole. When the power supply unit 700 applies a positive voltage to the first pipe charging unit P11, the ink particles (INK) and the first pipe charging unit (P11) have the same polarity, and the ink particles (INK) and the first pipe charging unit (P11) have the same polarity. A repulsive force acts between the charging portions (P11) to prevent ink particles (INK) from sticking to the inside of the first pipe (P1). More specifically, the ink particles (INK) may move inside the first pipe (P1) in the direction of flow speed and may contact the inner wall of the first pipe (P1) due to various influences such as gravity. In this case, the distance between the ink particle (INK) and the first pipe charging part (P11) disposed at the bottom in the drawing is narrowed, and the first pipe charging part (P11) is directed to the ink particle (INK) in the direction of the first force. A strong repulsive force can be applied. Accordingly, the ink particles (INK) in contact with the inner wall of the first pipe (P1) are applied in the direction of the first force and do not fall from the inner wall of the first pipe (P1) and aggregate at the lower position inside the first pipe (P1). It is possible to move inside the first pipe (P1) without. Likewise, the ink particles (INK) that have moved to the upper part of the drawing may not aggregate on the upper part of the first pipe (P1) by receiving a repulsive force in the direction of the second force from the first pipe charging portion (P11) disposed at the top. there is. In other words, the problem of settling of the ink particles (INK) inside the first pipe (P1) is prevented by applying a voltage of the same polarity as that of the ink particles (INK) to the first pipe charging unit (P11) using the power supply unit 700. can do. Although the inkjet printing device 1 includes a Teflon-based material and the ink particles (INK) are positively charged, the description is not limited thereto. For example, depending on the components included in the inkjet printing device 1, the ink particles (INK) may be charged to the -pole, and in this case, the power supply unit 700 applies a -pole voltage to the first pipe charging unit (P11). It is also possible to prevent the problem of sedimentation of ink particles (INK).

The second pipe (P2) may have substantially the same shape and configuration as the first pipe (P1).

11 is a schematic diagram of a first pipe according to another embodiment.

The first pipe (P1) according to this embodiment is different from the embodiment of FIG. 9 in the arrangement of the first pipe charging portion (P11).

Referring to FIG. 11 , the first pipe charging portion (P11_1) may cover only a portion of the first pipe (P1). More specifically, the first pipe charging portion (P11_1) may be made of a conductive material and may be disposed to cover the inner or outer wall of the first pipe (P1) in a net-like structure. In other words, the first pipe charging unit (P11_1) includes a horizontal charging unit and a column charging unit, and at the point where the row charging unit and the column charging unit intersect, the row charging unit and the column charging unit are electrically connected to each other. can be connected The power supply unit 700 may be connected to some of the horizontal charging unit or the thermal charging unit of the first pipe charging unit (P11_1). Accordingly, the first pipe charging unit (P11_1) does not cover the entire surface of the first pipe (P1), but when a voltage is applied from the power supply unit 700 to a part of the first pipe charging unit (P11_1), the first pipe charging unit (P11_1) is connected to the first pipe charging unit (P11_1). Voltage can be applied to all of (P11_1). By forming the first pipe charging portion (P11_1) in a mesh structure in this way, even if a part of the first pipe charging portion (P11_1) is lost and the voltage applied by the voltage source is not applied to a specific portion, the remaining portion is electrically connected to the first pipe. It may not affect the voltage applied to the entire pipe charging section (P11_1).

Figure 12 is a schematic diagram of a first pipe according to another embodiment.

The inkjet printing device 1 according to this embodiment is different from the embodiments of FIGS. 1 to 10 in that it does not include a power supply unit 700.

Referring to FIG. 12, the inkjet printing device 1 may not include the power supply unit 700. The first pipe (P1) may include a first pipe charging portion (P11_2) and a first pipe insulating portion (P12). The first pipe charging portion (P11_2) may be formed by charging some components included in the first pipe (P1) to the + pole or - pole using corona discharge or friction charging. More specifically, the first pipe charging portion (P11_2) can be charged to the same polarity as the polarity with which the ink particles (INK) are charged using a method such as corona discharge or friction charging.

The ink particles (INK) and the first pipe charging section (P11_2) have the same polarity, and a repulsive force acts between the ink particles (INK) and the first pipe charging section (P11_2), so that the ink particles (INK) are connected to the first pipe charging section (P11_2). It can be prevented from sticking to the inside of the pipe (P1). More specifically, the ink particles (INK) move inside the first pipe (P1) in the flow direction (D1) and may contact the inner wall of the first pipe (P1) due to various influences such as gravity. In this case, the distance between the ink particle (INK) and the first pipe charging part (P11_2) disposed at the bottom in the drawing is narrowed, and the first pipe charging part (P11_2) is directed to the ink particle (INK) in the direction of the first force ( Fa) can apply a strong repulsive force. Accordingly, the ink particles (INK) in contact with the inner wall of the first pipe (P1) are applied with a force in the direction of the first force (Fa) and are separated from the inner wall of the first pipe (P1) at a lower position inside the first pipe (P1). It can move inside the first pipe (P1) without agglomerating. Likewise, the ink particles (INK) that moved to the top in the drawing receive a repulsive force in the direction of the second force (Fb) from the first pipe charging portion (P11_2) disposed at the top and coalesce at the top of the first pipe (P1). It may not work.

In the drawing, it is assumed that the first pipe charging portion (P11_2) and the ink particles (INK) are charged to the + pole, but this is not limited. For example, the ink particles (INK) are charged to the -pole, and the first pipe charging portion (P11_2) may also be charged to the -pole using a method such as corona charging or friction charging.

The first pipe insulating portion (P12) includes an insulating material and may cover the first pipe electrifying portion (P11_2). Accordingly, the charging state of the first pipe charging unit (P11_2) can be maintained. In other words, the first pipe insulating portion (P12) covers the first pipe electrifying portion (P11_2), so that the first pipe electrifying portion (P11_2) contacts an external conductive object and electrons in the first pipe electrifying portion (P11_2) It is possible to prevent electrons from escaping to the outside or flowing into the first pipe charging unit (P11_2) from changing the charging state of the first pipe charging unit (P11_2).

13 and 14 are schematic diagrams of a first pipe according to another embodiment.

The first pipe (P1) according to this embodiment includes first flow pipes (P13a, P13b), and the first pipe charging portion (P11_3) is arranged to be spaced apart from the first flow pipes (P13a, P13b). There is a difference from Example 12.

Referring to FIGS. 13 and 14, the first pipe (P1) is arranged to be spaced apart from the first flow pipes (P13a, P13b) and the first flow pipes (P13a, P13b) that provide a movement path for ink particles (INK). It may include a first pipe electrification unit (P11_3). The first pipe charging portion (P11_3) may be formed by being charged to the + pole or - pole using the above-described corona discharge or friction charging method. The first pipe charging portion (P11_3) is arranged to be spaced apart from the first flow pipes (P13a, P13b). As described above, the first pipe charging portion (P11_3) can be charged to either the + pole or the - pole, but the description below assumes that it is charged to the + pole.

When the first flow tube (P13a) includes a conductor, the free electrons in the first flow tube (P13a) receive a repulsive force from the first pipe charging part (P11_3) and are emitted by the first pipe charging part (P11_3). 1 They are collected on the inner wall of the flow pipe (P13a_1) and arranged as shown in FIG. 13. Accordingly, the inner wall of the first flow pipe (P13a_1) has a positive charge, and the outer wall of the first flow pipe (P13a_2) has a negative charge.

When the first flow tube (P13b) contains a non-conductor, the atoms of the first flow tube (P13b) are moved by the first pipe charging part (P11_3) in a direction where the - pole is close to the first pipe charging part (P11_3), + The pole is rotated in a direction away from the first pipe charging portion (P11_3) and is arranged as shown in FIG. 14. Accordingly, the inner wall of the first flow pipe (P13b_1) has a positive charge, and the outer wall of the first flow pipe (P13b_2) has a negative charge.

The ink particles (INK) and the first flow tube inner walls (P13a_1, P13b_1) have the same polarity, and a repulsive force acts between the ink particles (INK) and the first flow tube inner walls (P13a_1, P13b_1), so that the ink particles (INK) ) can be prevented from sticking to the inside of the first pipe (P1). More specifically, the ink particles (INK) may move inside the first pipe (P1) in the direction of flow speed and may contact the inner wall of the first pipe (P1) due to various influences such as gravity. In this case, the distance between the corresponding ink particle (INK) and the first flow pipe inner wall (P13a_1, P13b_1) disposed at the bottom in the drawing is narrowed, and the first flow pipe inner wall (P13a_1, P13b_1) is attached to the corresponding ink particle (INK) A strong repulsive force can be applied in the direction of the force. Accordingly, the ink particles (INK) in contact with the inner wall of the first pipe (P1) are applied in the direction of the first force and do not fall from the inner wall of the first pipe (P1) and aggregate at the lower position inside the first pipe (P1). It is possible to move inside the first pipe (P1) without. Likewise, the ink particles (INK) that moved to the upper part of the drawing receive a repulsive force in the direction of the second force from the inner walls of the first flow pipe (P13a_1, P13b_1) disposed at the upper part and do not aggregate at the upper part of the first pipe (P1). It may not be possible.

Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing its technical idea or essential features. You will be able to understand it. Therefore, the embodiments described above should be understood as limited in all respects and not adversarial.

200: Print head 250: Head charging unit
40: Reservoir 43: Reservoir Daejeonbu
P1: 1st pipe P11: 1st pipe charging section
300: Power supply INK: Ink particles

Claims (20)

A print head including a nozzle that ejects ink onto a substrate;
an ink supply unit including a reservoir that stores the ink, a manifold that receives the ink from the reservoir, and a damper that provides a movement path for the ink between the manifold and the nozzle; and
a first pipe providing a path for the ink from the reservoir to the manifold; Including,
At least one of the print head, the ink supply unit, and the first pipe includes a charging unit that changes the charging state of the print head, the ink supply unit, or the first pipe,
An inkjet printing device further comprising a power supply unit that applies voltage to the charging unit. According to claim 1,
The inkjet printing device wherein the reservoir includes a reservoir charging unit that receives voltage from the power supply unit. According to clause 2,
The reservoir charging portion is in direct contact with the ink stored in the reservoir. According to clause 2,
Further comprising a second pipe providing a path for remaining ink from the print head to the reservoir,
The second pipe includes a second pipe charging unit that receives voltage from the power supply and changes the charging state of the second pipe. According to clause 4,
It further includes a pump disposed in the second pipe, pressurizing the remaining ink and supplying it to the reservoir,
The pump is an inkjet printing device including a pump charging unit that receives voltage from the power supply and changes the charging state of the pump. According to clause 5,
An inkjet printing device in which the magnitude of the voltage applied by the power unit to the charging unit varies depending on the arrangement of the charging unit. According to clause 4,
The first pipe includes a first pipe charging unit that changes the charging state of the first pipe,
An inkjet printing device wherein the first pipe charging portion and the second pipe charging portion include a conductive material. According to claim 1,
The power unit includes a direct current power source, the print head includes a head charging unit that changes the charging state of the print head, and the first pipe includes a first pipe charging unit that changes the charging state of the first pipe. ,
The voltage applied by the power supply to the head charging unit or the first pipe charging unit has the same polarity as the polarity in which the ink is charged. According to clause 8,
The inkjet printing device wherein the magnitude of the voltage applied by the power supply to the head charging portion is different from the magnitude of the voltage applied to the first pipe charging portion. According to claim 1,
The first pipe includes a first pipe charging unit that changes the charging state of the first pipe,
When the power unit is turned on and voltage is applied to the first pipe charging unit, the first pipe charging unit applies a repulsive force to the ink inside the first pipe. According to claim 1,
The first pipe is made of Teflon, and includes a first pipe charging unit that changes the charging state of the first pipe, and the power supply unit applies a positive voltage to the first pipe charging unit. a reservoir that stores ink charged to a first polarity and includes a reservoir charging portion charged to the first polarity;
a print head including a nozzle for discharging the ink on a substrate and a head charging unit charged to the first polarity;
an ink supply unit including a manifold that receives ink from the reservoir, a damper that provides a movement path for the ink between the manifold and the nozzle, and an ink supply unit charging unit charged to the first polarity;
a first pipe that provides a path for the ink from the reservoir to the print head and includes a first pipe charging portion charged to the first polarity; and
A second pipe providing a path for remaining ink from the print head to the reservoir and including a second pipe charging portion charged to the first polarity. According to claim 12,
The head charging unit, the first pipe charging unit, the second pipe charging unit, the ink supply charging unit, and the reservoir charging unit are in direct contact with the ink. According to claim 13,
The head charging unit, the first pipe charging unit, the second pipe charging unit, the ink supply charging unit, and the reservoir charging unit are charged by corona discharge. According to claim 13,
The head charging unit, the first pipe charging unit, the second pipe charging unit, the ink supply charging unit, and the reservoir charging unit are charged by friction charging. According to claim 13,
The head charging unit, the first pipe charging unit, the second pipe charging unit, the ink supply charging unit, and the reservoir charging unit include a conductive material,
a head insulating portion disposed in a direction opposite to the ink with the head charging portion interposed therebetween;
A first pipe insulating portion disposed in a direction opposite to the ink with the first pipe charging portion interposed therebetween,
a second pipe insulating portion disposed in a direction opposite to the ink with the second pipe electrifying portion interposed therebetween;
an ink supply unit insulator disposed in a direction opposite to the ink with the ink supply unit charging unit interposed therebetween;
An inkjet printing device further comprising a reservoir insulating part disposed in a direction opposite to the ink with the reservoir charging part interposed therebetween. According to claim 16,
The head insulation portion electrically separates the head charging portion,
The first pipe insulation portion electrically separates the first pipe electrification portion,
The second pipe insulating portion electrically separates the second pipe charging portion,
The ink supply unit insulator electrically separates the ink supply unit,
The reservoir insulating part electrically separates the reservoir charging part from the inkjet printing device. According to claim 12,
The first pipe includes a first flow pipe that is in contact with the ink and serves as a passage for the ink,
An inkjet printing device wherein the first pipe charging portion is arranged to be spaced apart from the first flow pipe. According to clause 18,
Due to electromagnetic induction by the first pipe charging unit, the outer wall of the first flow pipe has a second polarity different from the first polarity,
An inkjet printing device wherein the inner wall of the first flow tube has the first polarity. According to clause 19,
An inkjet printing device in which the inner wall of the first flow tube and the ink apply a repulsive force to each other.

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