KR20060133338A - Ink jet printing device and ink jet printing method - Google Patents

Abstract

An ink-jet printing device and an ink-jet printing method are provided to individually measure a weight of an ejection material of a predetermined nozzle and then individually change a voltage applied to a piezoelectric device connected to the predetermined nozzle, thereby uniformly adjusting the ejection amount of the nozzle. An ink-jet printing method includes the steps of applying a voltage to a plurality of piezoelectric devices in an ink-jet head(400) from a power supply to eject a predetermined material from a plurality of nozzles in the ink-jet head, measuring a weight of the material ejected from a predetermined nozzle of the plurality of nozzles, and changing a voltage applied to a piezoelectric device connected to the predetermined nozzle according to the weight measured result.

Description

Ink Jet Printing Equipment and Ink Jet Printing Method

1 is a cross-sectional view schematically showing a method of applying an alignment film using a conventional roll printing equipment.

2 is a perspective view schematically showing an inkjet printing apparatus according to an embodiment of the present invention.

3 is a schematic cross-sectional view of an inkjet printing apparatus according to an embodiment of the present invention.

<Description of Signs of Major Parts of Drawing>

400: head 420: supply pipe

440: nozzle 460: piezoelectric element

500: voltage application unit 550: variable resistor

600: plate 610: hole

650: protrusion 700: weighing device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to manufacturing equipment for liquid crystal display devices, and more particularly, to inkjet printing equipment which is equipment for forming alignment films and the like of liquid crystal display devices.

Ultra-thin flat panel displays with a display screen thickness of only a few centimeters (cm). Among them, liquid crystal displays have low operating voltages, which consume less power and can be used as portable devices. Applications range from monitors to spacecraft to aircraft.

Such a liquid crystal display device generally includes a lower substrate and an upper substrate facing each other at a predetermined interval, and a liquid crystal layer formed between the two substrates, and depending on whether voltage is applied between the two substrates. The arrangement is changed and thus the light transmittance is changed so that the image is reproduced.

At this time, if the arrangement state of the liquid crystal layer is disordered with or without voltage applied, it is difficult to obtain a desired image, so that an alignment layer is formed on the lower substrate and the upper substrate to make the initial arrangement state of the liquid crystal layer constant.

As a method of forming such an alignment film, the rubbing orientation method and the photo-alignment method are largely used.

The rubbing orientation method is a method of aligning the alignment material in a predetermined direction by applying an alignment material on a substrate in the form of a thin film, and then rotating a rubbing roll wound with a rubbing cloth.

The photo-alignment method is a method of applying an alignment material on a substrate in the form of a thin film, and then irradiating the alignment material with UV light such as polarized light or non-polarized light to align the alignment material in a predetermined direction by reacting with the UV light.

In order to obtain an alignment film aligned in a predetermined direction by applying the rubbing orientation method or the photoalignment method, first, the alignment material must be uniformly applied on the substrate in the form of a thin film.

Hereinafter, a method of applying a conventional alignment material on a substrate with reference to the drawings will be described.

1 is a cross-sectional view schematically showing a method of applying an alignment film using a conventional roll printing equipment.

First, after briefly explaining the structure of the conventional roll printing equipment, a process of applying the alignment film using the roll printing equipment will be described.

Conventional roll printing equipment includes a substrate stage 12 for supporting the substrate 10, a dispenser 14 for supplying an alignment material, and three rolls 16, 18, and 20.

The three rolls are named doctor roll 16, annealing roll 18, and printing roll 20 in order from the top, and the doctor roll 16 is engaged with the anniex roll 18, 18 is engaged with the printing roll 20.

A rubber plate 22 is attached to the printing roll 20 in accordance with a coating pattern of a desired alignment material.

Looking at the method of applying the alignment film using the roll printing equipment having such a structure, first, the alignment material 15 in the dispenser 14 is supplied between the doctor roll 16 and the annix roll 18. At this time, since the doctor roll 16 and the annix roll 18 and the annix roll 18 and the printing roll 20 are engaged with each other and rotate in the direction of the arrow, the doctor roll 16 and the annix roll ( The alignment material 15 supplied between 18 is uniformly applied to the rubber plate 22 of the printing roll 20 via the annealing roll 18.

On the other hand, the substrate 10 is mounted on the substrate stage 12, and moves in a predetermined direction from the lower portion of the printing roll (20). As the substrate stage 12 moves as described above, the substrate 10 seated on the substrate stage 12 and the rubber plate 22 of the printing roll 20 come into contact with each other, and the alignment material applied to the rubber plate 22 is applied. The substrate 10 is transferred onto the substrate 10, so that the alignment material is applied onto the substrate 10.

However, in the case of applying the alignment material on the substrate using such a roll printing equipment, firstly, the size of the three rolls must be changed as the model size of the liquid crystal display device is changed. There is a disadvantage in that the manufacturing cost is increased due to a lot of waste material costs due to the large number of alignment materials.

Therefore, a method of applying an alignment material that can flexibly cope with a model size change and reduce costs by replacing a roll printing device has been studied. Accordingly, a method of applying an alignment material onto a substrate using an inkjet printing device has been developed. Proposed.

Conventional inkjet printing equipment includes an inkjet head having a plurality of nozzles for discharging the alignment material, and since the discharge of the alignment material can be selectively performed from the plurality of nozzles by applying a predetermined voltage, the model of the liquid crystal display device. Even if the size is changed, it is possible to appropriately handle and minimize the discarded alignment materials.

However, in such a conventional inkjet printing equipment, the discharge amounts of the alignment materials discharged from the plurality of nozzles may not all be the same at the plurality of nozzles, but may exhibit different discharge amounts. As described above, when the discharge amount of the alignment material is different in each of the plurality of nozzles, a problem arises in uniformly applying the alignment film.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an inkjet printing method and an inkjet printing apparatus capable of printing while maintaining the same discharge amount discharged from a plurality of nozzles.

In order to achieve the above object, the present invention comprises the steps of: applying a voltage to a plurality of piezoelectric elements in the inkjet head from the voltage applying unit to discharge a predetermined material from the plurality of nozzles in the inkjet head; Measuring a weight of a discharge material discharged from a predetermined one of the plurality of nozzles under the inkjet head; And varying a voltage applied to the piezoelectric element connected to the predetermined nozzle according to the weight measurement result.

That is, in the present invention, by measuring the weight of the discharge material discharged from the predetermined nozzle individually, by changing the voltage applied to the piezoelectric element connected to the predetermined nozzle individually to adjust the discharge amount discharged from the nozzle, the same amount in the entire nozzle It is to be discharged.

In this case, the step of measuring the weight of the discharge material is preferably performed by placing a weighing device under the inkjet head with a plate having a predetermined hole therebetween. Here, the hole formed in the plate may be formed so that only the discharge material discharged from one of the plurality of nozzles can pass through, in which case the discharge amount can be corrected for each nozzle.

The step of varying the voltage is preferably performed by varying the resistance value of the variable resistor by installing a variable resistor corresponding to the plurality of piezoelectric elements in the voltage applying unit.

The present invention also provides an inkjet head including a plurality of nozzles and a plurality of piezoelectric elements; A voltage applying unit electrically connected to the piezoelectric elements to apply voltages to the plurality of piezoelectric elements, the voltage applying unit including a plurality of variable resistors for adjusting a voltage applied to each of the plurality of piezoelectric elements; A plate movable in a lower portion of the inkjet head and having holes formed therein so as to allow only discharge material discharged from a predetermined nozzle to pass therethrough; And a weighing device for measuring the weight of the discharge material discharged from the hole of the plate.

The hole formed in the plate may be formed so that only the discharge material discharged from one of the plurality of nozzles may pass therethrough.

In addition, the plate is preferably formed with a protrusion having a hole corresponding to the hole.

The plate or inkjet head is preferably movable on the x and y axes.

In addition to the nozzle and the piezoelectric element, the inkjet head may be provided with a supply pipe through which a predetermined material flows between the nozzle and the piezoelectric element.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

2 and 3 are a perspective view and a cross-sectional view schematically showing the inkjet printing equipment for adjusting the discharge amount according to an embodiment of the present invention, respectively.

2 and 3, the inkjet printing apparatus according to the present invention includes an inkjet head 400, a voltage applying unit 500, a plate 600, and a weighing apparatus 700.

The inkjet head 400 includes a plurality of supply pipes 420, a plurality of nozzles 440, and a plurality of piezoelectric elements 460.

The supply pipe 420 is a flow path of a predetermined material such as an alignment material, and is a passage through which the predetermined material flows into the head 400 from the outside.

The nozzle 440 is connected to the supply pipe 420 at a predetermined portion, and a predetermined material is discharged to the outside through the nozzle 440.

The piezoelectric element 460 is formed on the opposite side of the nozzle 440 with the supply pipe 420 interposed therebetween. The piezoelectric element 460 causes physical deformation by applying a voltage to contract the flow path of the supply pipe 420 so that a predetermined material may be discharged from the supply pipe 420 to the outside through the nozzle 440.

A piezoelectric element is an element which exhibits a piezoelectric phenomenon, and is also called a piezoelectric element. Piezoelectric phenomenon is a phenomenon in which positive and negative charges are proportional to external forces on both sides of a plate when a certain type of crystal plate is applied in a certain direction. In 1880, Jacques Curie and Pierre of France First discovered by Brother Curie (1859-1906). Since the piezoelectric power on a single sheet is weak, it is known that the amount of the piezoelectric material increases greatly when the sheets are overlapped with each other. It was also found that there is an inherent vibration in the crystal plate and that when the elastic vibration and the electric vibration coincide, the vibration is combined with the piezoelectric force to generate a stronger vibration.

The piezoelectric element is designed to be applicable to various fields by using such a phenomenon. As the material of the piezoelectric element, crystal, tourmaline, Rochelle salt, etc. are used, and barium titanate, ammonium dihydrogen phosphate, ethylene tartarate, etc. developed in recent years Artificial crystals such as diamine are also excellent in piezoelectricity and are used as piezoelectric elements.

The voltage applying unit 500 includes a power source 510 and a plurality of variable resistors 550.

The voltage applying unit 550 is for applying a voltage to the plurality of piezoelectric elements 460 of the head 400, and is electrically connected to the plurality of piezoelectric elements 460, and the plurality of piezoelectric elements 460. A plurality of variable resistors 550 are formed to correspond to the number of), so that the magnitude of the voltage applied to each of the plurality of piezoelectric elements 460 can be adjusted.

The plate 600 is positioned below the head 400 and has a predetermined hole 610 formed therein, and is discharged from a predetermined nozzle among the plurality of nozzles 440 of the head 400. Allow only discharged material to pass through. Here, when the hole 610 is formed so that only the discharge material discharged from one nozzle 440 can pass, the weight of only the discharge material discharged from the nozzle 440 can be measured.

The plate 600 may further include a protrusion 650 having a hole corresponding to the hole 610. When the protrusion 650 is additionally formed, a more accurate weight of the discharged material may be measured. That is, when a voltage is applied to the head 400, the alignment materials are discharged simultaneously from the plurality of nozzles 440, so that the alignment materials discharged from nozzles other than a predetermined nozzle are lowered through the holes 610. It may fall, so that the weight of the alignment material discharged from the predetermined nozzle cannot be accurately measured. Therefore, it is preferable to form a protrusion 650 having a hole corresponding to the hole 610 in the plate 600.

On the other hand, in order for the discharge material discharged from the plurality of nozzles 440 to pass through the holes 610 of the plate 600 individually, a position change is necessary, and thus, among the inkjet head 400 and the plate 600. At least one is preferably movable on the x and y axes.

The weighing apparatus 700 is positioned under the plate 600 to measure the weight of the discharge material discharged from the hole 610 of the plate 600.

As the weighing device 700, any device capable of weighing such as an electronic balance may be applied.

In addition, although not shown, the inkjet head 400 is connected to a supply tank. Specifically, the supply pipe 420 of the inkjet head 400 is connected to the external pipe, the external pipe is connected to the supply tank. The supply tank stores a predetermined material such as an alignment material, and the stored predetermined material is supplied to the head 400 through the supply pipe 420 of the head 400 through the pipe.

The printing method using the inkjet printing apparatus according to the present invention described above is as follows.

First, the voltage applying unit 500 applies a voltage to the plurality of piezoelectric elements 460 of the inkjet head 400. At this time, the resistance values of the plurality of variable resistors 550 of the voltage applying unit 500 are all set the same. As such, when a voltage is applied to the piezoelectric element 460, the piezoelectric element 460 causes physical deformation, and accordingly, a flow path of the supply pipe 420 is contracted so that the alignment material is discharged to the outside through the nozzle 440 on the opposite side. .

Subsequently, only the alignment material discharged from the nozzle 440 at a predetermined position among the alignment materials discharged by positioning the plate 600 having a predetermined hole 610 under the head 400 passes through the plate 600. Do it. Then, the alignment material passing through the plate 600 falls on the weighing apparatus 700 and the weight is measured.

Thereafter, when the measured weight is different from the predetermined weight, the variable resistor 550 connected to the piezoelectric element 460 associated with the discharged alignment material among the plurality of variable resistors 550 of the voltage applying unit 500. Adjust the resistance value.

In addition, by moving the plate 600 or the head 400 in the X-axis and / or Y-axis, the weight of all the discharge material discharged from the plurality of nozzles 440 of the head 400 as described above After the measurement, the discharge amount is individually adjusted by adjusting the resistance value of the variable resistor 550.

The above is only a description of a preferred embodiment of the present invention, the present invention is not limited to the above embodiment, various modifications can be made within the scope not changing the technical spirit of the present invention.

According to the above configuration, the present invention can individually adjust the voltage applied to the piezoelectric element connected to the predetermined nozzle after individually measuring the weight of the discharge material discharged from the predetermined nozzle to uniformly adjust the discharge amount discharged from the nozzle, Uniform application is possible.

Claims (10)

Applying a voltage to the plurality of piezoelectric elements in the inkjet head from the voltage applying unit to discharge a predetermined material from the plurality of nozzles in the inkjet head; Measuring a weight of a discharge material discharged from a predetermined one of the plurality of nozzles under the inkjet head; And varying a voltage applied to the piezoelectric element connected to the predetermined nozzle according to the weight measurement result. The method of claim 1, And measuring the weight of the discharge material is performed by placing a weighing device under the inkjet head with a plate having a predetermined hole formed therebetween. The method of claim 2, And a hole formed in the plate so that only the discharge material discharged from one of the plurality of nozzles can pass therethrough. The method of claim 1, And the step of varying the voltage is performed by varying a resistance value of a variable resistor formed in the voltage applying unit. An inkjet head including a plurality of nozzles and a plurality of piezoelectric elements; A voltage applying unit electrically connected to the piezoelectric elements to apply voltages to the plurality of piezoelectric elements, the voltage applying unit including a plurality of variable resistors for adjusting a voltage applied to each of the plurality of piezoelectric elements; A plate positioned below the inkjet head and having holes formed therein so as to allow only discharge material discharged from a predetermined nozzle to pass therethrough; And And a weighing device for measuring the weight of the discharge material discharged from the hole of the plate. The method of claim 5, The inkjet head is an inkjet printing equipment, characterized in that the supply pipe for the predetermined material flows between the nozzle and the piezoelectric element is further formed. The method of claim 5, And a hole formed in the plate so that only the discharge material discharged from one of the plurality of nozzles can pass therethrough. The method of claim 5, And the plate is movable on an x-axis and a y-axis. The method of claim 5, And the inkjet head is movable on the x-axis and the y-axis. The method of claim 5, Ink plate printing equipment, characterized in that the plate is further formed with a projection having a hole corresponding to the hole.

Images