KR20160021495A - Apparatus and method for transfer and tension-control of flexible substrate in roll-to-roll printing equipment - Google Patents

Abstract

The present invention relates to an apparatus and a method to transfer a flexible substrate of roll-to-roll printing equipment and control the tension of a flexible substrate and, more specifically, to an apparatus and a method to transfer a flexible substrate of roll-to-roll printing equipment and control the tension of a flexible substrate, which maintain the best printing quality by minimizing the influence of a thermal strain caused when a flexible substrate is dried in roll-to-roll printing equipment. According to the present invention, a device for absorbing a tension change caused by the thermal strain of the flexible substrate is formed between printing units, and the transferring speed of the flexible substrate in each printing unit is corrected to precisely control the tension of the flexible substrate, thereby maintaining the best printing quality by minimizing the influence of the thermal strain.

Description

TECHNICAL FIELD [0001] The present invention relates to a flexible substrate transferring and tension control apparatus and method for a roll-to-

The present invention relates to an apparatus and method for flexible substrate transfer and tension control in a roll-to-roll printing machine, and more particularly, to a method and apparatus for flexible substrate transfer and tension control in a roll- To a flexible substrate transfer and tension control apparatus and method for a roll-to-roll printing machine.

Printed electronics, which produces electronic devices by the recent printing method, is in the spotlight and includes mass-produced low-cost products such as RFID antennas, polymer transistors, flexible displays and solar cells. As a conventional printing machine, it is necessary to produce printed electronic devices with a precision of several tens to several micros, which can produce products capable of performing electronic devices.

1 is a view showing a configuration of a conventional roll-to-roll printing machine 10.

Among these printing electronic products, roll-to-roll printing equipment is attracting attention in a way that can produce flexible large-area products in large quantities and at low cost. The roll-to-roll printing apparatus is a system in which a substrate 20 in the form of a web of a flexible material such as film or paper is fed from an un-winder 11 to a re-winder 12 ) Is a device to which a printing electronic device is fabricated on the flexible web substrate 20 by using various printing methods during the winding process of the web substrate 20. In order to smoothly supply and take up the web substrate 20, web handling) is one of the important technologies. Particularly, since stable feeding with minimal deformation of the web substrate greatly affects the registration accuracy required for the production of the device, the speed synchronization between the printing roll and the feeder roll and the tension control of the span are very good It becomes an important technology.

In particular, in the case of printing electrons, the drying temperature of the ink mainly used is 100 ° C. or more. In the case of the polymer film used here, physical and chemical deformation at such a high temperature is easily caused, Expanding or contracting, and this effect becomes even greater as the temperature increases.

When there is no deformation of the web substrate after passing through the dryer 13, ideally, as shown in Fig. 1, the linear velocity v1 of the web substrate by the roller driving the printing unit 1 and the roller driving the printing unit 2 When the linear velocity v2 of the web substrate is the same (v1 = v2), the tension T1 between the two printing units is kept constant, so that the web can smoothly be supplied to the rollers without slip.

In practice, however, there is a deformation of the web substrate after passing through the dryer, which is problematic if v1 and v2 remain the same. That is, when the web substrate shrinks, T1 becomes large, and eventually the web substrate slips due to the roller. When the web substrate expands, T1 becomes small and the web substrate is eventually slackened. Therefore, it is necessary to supply the web substrate smoothly and to maintain the tension by changing v1 and v2 according to the deformation amount of the web substrate. However, since it is difficult to calculate such a correction amount by mathematical calculation, it is necessary to experimentally calculate the correction amount during the process and give a difference in the correction amount to v1 and v2. However, when the speed of the printing unit is corrected in real time, There has been a problem in that a change in the tension between the printing units affects all the spans before and after the printing unit and the entire printing process is not smooth.

KR 10-2013-0019298 A

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and has an apparatus for absorbing a change in tension due to thermal deformation of a flexible substrate between printing units. In order to correct a feeding speed of a flexible substrate in each printing unit The present invention aims to precisely control the tension of a flexible substrate to minimize the influence of thermal deformation and to maintain the best print quality.

In order to achieve the above object, a flexible substrate transfer and tension control apparatus of a roll-to-roll printing apparatus according to the present invention is characterized in that it comprises two printing units (hereinafter referred to as "printing unit 1" and "printing unit 2" In order to keep the tension (T1) of the flexible substrate traveling from the printing unit 1 to the printing unit 2 constant, the span length of the flexible substrate (the flexible substrate between the printing unit 1 and the printing unit 2 (Hereinafter referred to as a "dancer" collectively referred to as a device performing such a function); And a dancer position control unit for measuring the tension (T1) of the flexible substrate between the dancer and the printing unit 2 and controlling the position of the dancer so that the tension (T1) is kept constant according to the measured tension .

The dancer position control unit moves the dancer in a direction in which the web span length becomes long when the flexible substrate having passed through the printing unit 1 and the dryer expands and the tension T1 becomes small, When the flexible substrate is contracted and the tension T1 is increased, the dancer can be moved in a direction in which the web span length is shortened.

The flexible substrate transporting and tensioning device may further include a feeder provided between the dancer and the printing unit 2 and separately controlling the tension T2 of the flexible substrate before entering the printing unit 2. [

The flexible substrate transferring and tension control device controls the transfer speed of the flexible substrate from the moving speed of the dancer measured from the position change of the dancer to the linear velocity v1 of the flexible substrate passing through the printing unit 1, And a movement speed correcting unit for calculating the correction amount of the speed v2 and controlling the linear speed v1 or v2 to be corrected by the calculated correction amount.

Wherein the movement speed of the dancer is periodically measured and the movement speed corrector performs a correction process of the linear velocity when the measured velocity of the dancer is equal to or greater than a preset reference value, The linear velocity correction process can be stopped.

The velocity correction amount? V to be applied to the linear velocity v1 or v2 can be calculated by? V = 2 · | v _dancer |, where v _dancer is the moving speed of the dancer.

The change in position of the dancer may be sensed using a position sensor or sensed using an encoder signal of a motor driving the dancer.

According to another aspect of the present invention, there is provided a flexible substrate transfer and tension control method for a flexible substrate transfer and tension control apparatus of a roll-to-roll printing press, comprising the steps of: (a) Measuring a tension (T1) And (b) moving and controlling a device capable of changing the span length of the flexible substrate (hereinafter referred to as a "dancer" collectively) And performing the operation of performing the operation.

In the step (b), when the flexible substrate having passed through the printing unit 1 and the dryer expands and the tension (T1) becomes small, the dancer is moved in a direction in which the web span length becomes long, The dancer can be moved in a direction in which the web span length is shortened when the passed flexible substrate shrinks and the tension T1 becomes large.

The flexible substrate transfer and tension control method may further include the step of separately controlling the tension T2 of the flexible substrate before the feeder provided between the dancer and the printing unit 2 enters the printing unit 2 .

(C1) measuring a moving speed of the dancer from a positional change of the dancer; (c2) calculating a correction amount of the linear velocity (v1) of the flexible substrate passed through the printing unit (1) or the linear velocity (v2) of the flexible substrate passing the printing unit (2) from the moving velocity of the dancer measured; And (c3) controlling the linear velocity v1 or v2 to be corrected by the calculated correction amount.

The moving speed measurement of the dancer of the step (c1) may be periodically performed, and the step (c2) may further include checking whether the measured speed of the dancer is equal to or greater than a predetermined reference value If the predetermined reference value is not less than the preset reference value, the step (c2) and the step (c3) may be performed. If the predetermined reference value is less than the preset reference value, the correction of the linear velocity may be stopped.

The velocity correction amount? V to be applied to the linear velocity v1 or v2 can be calculated by? V = 2 · | v _dancer |, where v _dancer is the moving speed of the dancer.

The change in position of the dancer may be sensed using a position sensor or sensed using an encoder signal of a motor driving the dancer.

According to the present invention, there is provided an apparatus for absorbing a change in tension due to thermal deformation of a flexible substrate between printing units, and precisely controlling the tension of the flexible substrate by correcting the feeding speed of the flexible substrate in each printing unit Thereby minimizing the influence of thermal deformation and maintaining the best print quality.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a configuration of a conventional roll-to-roll printing machine. FIG.
Fig. 2 is a view showing a configuration in which a dancer is installed between two printing units, according to the present invention. Fig.
Fig. 3 is a view showing a configuration in which a feeder is further provided in the configuration of Fig. 2 as a roll-to-roll printing apparatus according to the present invention.
Figure 4 shows an embodiment of another form of dancer;
Figure 5 is a graph of experimental results showing the change in position of the dancer to maintain the tension constant in the roll-to-roll printing equipment of Figure 2 or Figure 3;
6 is a view showing a configuration in the case where a feed speed correction unit of a web substrate in two print units is added in a roll-to-roll printing equipment;
Fig. 7 is a flowchart showing a flexible substrate transfer and tension control flow performed in a roll-to-roll printing apparatus having a function of correcting a feed speed of a web substrate in two printing units. Fig.
FIG. 8 is a graph of experimental results showing the change in the moving speed of the flexible substrate when the flexible substrate transfer and the tension control are performed according to the flowchart of FIG.
FIG. 9 is a graph of experimental results showing changes in the position of the dancer when the flexible substrate transferring and tension control is performed according to the flowchart of FIG. 7. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

Fig. 2 is a view showing a configuration in which a dancer is installed between two printing units, and Fig. 3 is a view showing a configuration in which a feeder is additionally provided in the configuration of Fig. 2 , Figure 4 is an illustration of an embodiment of another type of dancer that may be included in such printing equipment.

The flexible web substrate 30 moves in the direction of the printing unit 2 (120) from the printing unit 1 (110) to perform a printing operation. The dryer 130 dries the printed web substrate 30 in the printing unit 1 (110). As described above with reference to FIG. 1, in the case of a polymer film that can be used as a flexible web substrate, it is easy to cause physical and chemical deformation at such a high temperature so that the web substrate dried in the dryer 130 after the printing is expanded or contracted , This effect becomes even greater as the temperature increases.

2, a dancer or a compensator 140 (hereinafter referred to as a " printing unit 1 " and a printing unit 2) is provided between two printing units of a roll- ) Can be installed.

That is, a dancer or compensator 140 is installed between the printing unit 1 and the printing unit 2 of the roll-to-roll printing machine, so that the tension T1 of the flexible substrate traveling from the printing unit 1 to the printing unit 2 (The length of the flexible substrate between the printing unit 1 and the printing unit 2) of the flexible substrate in order to keep the position of the flexible printed board 2 constant. Hereinafter, Quot; dancer ".

2 and 3, the tension of the web substrate 30 is maintained by the up-and-down movement of the dancer 140. However, as shown in FIG. 4, The dancer of the present invention is not limited to the form according to these embodiments but may be modified in any way by its positional change so that the tension or shrinkage And a device capable of maintaining the tension of the web substrate at a constant level.

And a dancer position control unit 150 for controlling the position of the dancer 140. The dancer position control unit 150 measures the tension T1 applied to the web substrate 30 at the portion that enters the printing unit 2 120 and controls the position of the dancer 140 to keep T1 constant. 2 and 3, when the web substrate 30 is contracted and the tension T1 is increased, the dancer position control unit 150 moves the dancer 140 upward When the web substrate 30 expands and the tension T1 becomes small, the dancer position control unit 150 moves the dancer 140 downward to maintain the tension constant. 4, when the web substrate 30 is contracted to increase the tension T1, the dancer position control unit 150 moves the dancer 140 to the right (410) The dancer position control unit 150 moves the dancer 140 to the left side (420) to maintain the tension constant when the web substrate 30 expands and the tension T1 becomes small.

In FIG. 3, a feeder 160 may be further included in the configuration of FIG. That is, the tension T1 applied to the web substrate between the print unit 1 (110) and the feeder 160 is controlled by the up and down movement of the dancer 140, and the feeder 160 controls the feeder 160 and the print unit 2 (120 The tension T2 applied to the web substrate can be controlled. In this case, a more stable tension control effect can be obtained.

FIG. 5 is a graph of experimental results showing the change of the position of the dancer in order to keep the tension constant in the roll-to-roll printing equipment of FIG. 2 or FIG.

Each line on the graph represents the change in position of the dancer 140 with the drying temperature 510. The ordinate axis positive direction value means a height moved to the upper side with the reference position 1 of the dancer 140 moving up and down in Fig. 2 or Fig. 3 as zero. When the speed of the web substrate 30 from the printing unit 1 110 is v1 and the speed of the web substrate 30 from the printing unit 2 120 is v2 in Fig. 2 or Fig. 3, The span length between the two printing units at the time of shrinkage is shortened and the dancer 140 moves upward to keep the tension T1 constant. Here, the span length means the length of the web substrate 30 between the printing unit 1 (110) and the printing unit 2 (120), and the span length is shortened when shrinking through the dryer, It is said that the span length becomes longer.

Meanwhile, although the tension of the web substrate 30 can be kept constant by the position control of the dancer 140 by the dancer position controller 150 as described above, there is a limit in changing the position of the dancer 140 The tension control that depends only on the change of the position of the dancer 140 has a certain limit because it can not move in an infinite direction. The configuration and control method for solving these limitations will be described below with reference to Figs. 6 and 7. Fig.

Fig. 6 is a diagram showing a configuration in the case of adding a web feed forward speed correction unit 170 in two printing units in a roll-to-roll printing machine, and Fig. 7 is a diagram showing the relationship between the feeding speed Fig. 6 is a flowchart showing a flexible substrate transfer and tension control flow performed in a roll-to-roll printing machine with a correction function added thereto. Fig.

In the case of the configuration shown in FIG. 6, the dancer moves up and down as one embodiment. However, the description with reference to FIGS. 6 and 7 is also applicable to a dancer moving left and right as described with reference to FIG. 4 , It is the scope of the present invention that is applicable to any type of dancer as long as it is capable of keeping the tensile force of the flexible web substrate constant by moving its position as described above.

6, the feeder 160 may be provided without the feeder 160 according to circumstances.

Referring to the flowchart of FIG. 7, first, the drive linear velocity for driving each printing unit, that is, the feed rate of the web substrate 30, is initialized and driven (S701). Although only the speeds v1 and v2 according to the two printing units 110 and 120 are shown in this figure, it is to be understood that more printing units can be connected, and accordingly, the speeds in the respective printing units may also be equal to each other (v3, v4, ...). In this case, at initialization, each line speed can be initialized at the same speed (v1 = v2 = v3 = ...) or at an arbitrary speed. Thereafter, the dancer position control unit 150 adjusts and controls the position of the dancer in order to keep the tension T1 constant according to the tension T1 (S702).

Thereafter, the feed speed correction unit 170 measures the moving speed v _dancer of the dancer 140 according to the position of the dancer 140 according to the position of the dancer 140 adjusted at a predetermined time interval (S703). That is, as shown in Equation (1), the variation of the position of the dancer 140 is divided by the moving time of the moving distance to measure v _dancer . Regarding the method of detecting the position of the dancer, the dancer generally uses a method of using the position sensor, but there is also a method of utilizing the encoder signal of the motor that drives the dancer, without using the position sensor.

[Equation 1]

v _dancer = Dancer travel distance / Time during travel distance

Using the moving speed of the dancer 140, the linear velocities v1 and v2 in the printing units 110 and 120 are adjusted (S704). That is, the tension is maintained until the linear velocity in each printing unit is varied by exactly reflecting the deformation amount of the web, but if the linear velocity in each printing unit does not have this value, the movement of the dancer 140 is used The tension T1 can be kept constant. However, since the movement amount of the dancer 140 is limited, the linear velocities v1 and v2 are corrected to be different according to the movement amount of the dancer 140, So that it can be maintained.

The amount of change in the span length, which is the length of the web substrate 30 between the two printing units 110 and 120, is twice the amount of movement of the dancer 140. Therefore, the velocity correction amount? V to be applied to the linear velocity v1 or v2 in each of the printing units 110 and 120 can be calculated by the following equation (2).

&Quot; (2) "

V = 2 · | v _dancer |

That is, in the case (hereinafter referred to as '△ v _dancer') the reference value, the speed of the dancer v _dancer predetermined according to the position change of the dancer measured in step S703 prior or more (S704), using the measured v _dancer equations (2) and Similarly,? V is obtained (S705). If the web contracts and the tension increases, the tension of the web can be kept constant by increasing the speed of v1 by adding a correction amount? V to v1 or decreasing the speed of v2 by subtracting the correction amount? V from v2. On the contrary, when the web expands and the tension decreases, the tension of the web can be kept constant by decreasing the speed of v1 by subtracting the correction amount DELTA v from v1 or increasing the speed of v2 by adding the correction amount DELTA v to v2 .

(V2 '= v2 + Δv at the time of web expansion or v2' = v2 - Δv at the time of web contraction) or by adjusting v1 (v1 '= v1 - DELTA v; v1 '= v1 + DELTA v at the time of web shrinkage) By adjusting v1 and v2 according to contraction or expansion of the current substrate, the tension T1 is kept constant (S706) So that it can be smoothly conveyed without being influenced by slip or sagging. Where v1 'is the speed at which v1 is adjusted by correction, and v2' is the speed at which v2 is adjusted by correction.

If necessary, the correction amount is distributed to the two printing rolls without applying the correction amount only to the speed (v1 or v2) of one printing roll, and the tension can be maintained when the divided value is maintained only by Δv. For example, in the case of correction of the web contraction by v2 '= v2-k · Δv, v1' = v1 + (1-k) · Δv (0≤k≤1), v2'-v1 '= ) -? V = (initial velocity difference - correction amount) = (total velocity difference) so that the tension can be kept constant. As a special case, when the initial printing roll speed is the same (v1 = v2), the corrected speed difference is v2'-v1 '= - Δv.

Thereafter, the v _dancer continues to be periodically measured, for example at constant time intervals, so that | v _dancer | > V _dancer , the correction of v1 and v2 as described above is continued, and | v _dancer | <? V _dancer , the correction of v1 and v2 is stopped, and only the fine control of the position of the dancer 140 by the dancer position control unit 150 is performed (S707). Of course, even after | to continue periodically measuring the | | v _dancer v _dancer | > V _dancer , correction of v1 and v2 as described above is performed.

FIG. 8 is a graph showing an experimental result showing the change in the moving speed of the flexible substrate when the flexible substrate transferring and the tension control are performed according to the flowchart of FIG. 7, FIG. 9 is a graph showing the result of performing the flexible substrate transferring and tension control according to the flowchart of FIG. This is an experimental result graph showing the change of the position of the dancer in the case. The drying temperature is displayed at the top right (810,910)

That is, FIG. 8 shows a state in which the printing unit 2 is driven by finding the stable v2 by the correction amount calculated by the above-described method with reference to FIG. 7, and the initial speed of 20 mm / . 9 is a graph showing the position of the dancer 140 for maintaining a constant tension in this case, which indicates that the position of the dancer 140, which has been moved to the upper position, is maintained at a constant position by the speed synchronization operation of v2.

1: Upper and lower position origin of the dancer
10: Conventional roll-to-roll printing equipment
11: Printing unit 1
12: Printing unit 2
13: Dryer
20: flexible web substrate
100: Roll-to-roll printing equipment according to the present invention
30: flexible web substrate
110: print unit 1
120: print unit 2
130: dryer
140: The dancer
150: Dancer position control section
160: Feeder
170:
510,810,910: Display of drying temperature

Claims (14)

A flexible substrate transfer and tension control device for a roll-to-roll printing machine,
(T1) of the flexible substrate, which is installed between two printing units (hereinafter, referred to as 'printing unit 1' and 'printing unit 2') of the roll-to-roll printing machine and moves from the printing unit 1 to the printing unit 2, (Hereinafter, referred to as a &quot; device capable of performing such a function &quot; as referred to herein as a &quot; device capable of performing such a function &quot; Dancer '); And
A dancer position control unit for measuring the tension T1 of the flexible substrate between the dancer and the printing unit 2 and controlling the position of the dancer so that the tension T1 is kept constant according to the measured tension,
Wherein the flexible substrate transferring and tension controlling device includes: The method according to claim 1,
The dancer position control unit,
When the flexible substrate having passed through the printing unit 1 and the dryer is expanded and the tension T1 is reduced, the dancer is moved in a direction in which the web span length is long, and the flexible substrate passing through the printing unit 1 and the dryer is contracted When the tension T1 is increased, the dancer is moved in the direction in which the web span length is shortened
And a flexible substrate transferring and tensioning control device. The method according to claim 1,
A feeder provided between the dancer and the printing unit 2 for separately controlling the tension T2 of the flexible substrate before entering the printing unit 2,
Further comprising: a flexible substrate transferring and tension controlling device for transferring the flexible substrate. The method according to claim 1,
From the moving speed of the dancer measured from the change of the position of the dancer, the linear velocity v1 of the flexible substrate passed through the printing unit 1 or the linear velocity v2 of the flexible substrate passing through the printing unit 2, And controls the linear velocity v1 or v2 to be corrected based on the calculated correction amount.
Further comprising: a flexible substrate transferring and tension controlling device for transferring the flexible substrate. The method of claim 4,
The moving speed of the dancer is periodically measured,
Wherein the moving speed correction unit comprises:
The correction process of the linear velocity is performed when the velocity of the measured dancer is equal to or greater than a preset reference value and the correction process of the linear velocity is stopped when the velocity of the measured dancer is less than a preset reference value
And a flexible substrate transferring and tensioning control device. The method of claim 4,
The velocity correction amount? V to be applied to the linear velocity v1 or v2 is expressed by the following equation
V = 2 · | v _dancer |
, Where v _dancer is the moving speed of the dancer
And a flexible substrate transferring and tensioning control device. The method of claim 4,
The change of the position of the dancer,
Detected using a position sensor or detected using the encoder signal of the motor driving the dancer
And a flexible substrate transferring and tensioning control device. A flexible substrate transfer and tension control method for flexible substrate transfer and tension control of roll to roll printing equipment,
(a) measuring a tension (T1) of a flexible substrate going from the printing unit 1 of the roll-to-roll printing equipment to the printing unit 2; And
(b) a movement control device for changing a span length of the flexible substrate (hereinafter referred to as a "dancer") is used to maintain the tension T1 constant Steps to Perform a Task
And a flexible printed circuit board. The method of claim 8,
In the step (b)
When the flexible substrate having passed through the printing unit 1 and the dryer is expanded and the tension T1 is reduced, the dancer is moved in a direction in which the web span length is long, and the flexible substrate passing through the printing unit 1 and the dryer is contracted When the tension T1 is increased, the dancer is moved in the direction in which the web span length is shortened
Wherein the flexible substrate transferring and tension control method comprises: The method of claim 8,
A feeder provided between the dancer and the printing unit 2 controls separately the tension T2 of the flexible substrate before entering the printing unit 2
Further comprising the step of transferring the flexible substrate. The method of claim 8,
(c1) measuring a moving speed of the dancer from a change in the position of the dancer;
(c2) calculating a correction amount of the linear velocity (v1) of the flexible substrate passed through the printing unit (1) or the linear velocity (v2) of the flexible substrate passing the printing unit (2) from the moving velocity of the dancer measured; And
(c3) controlling the linear velocity v1 or v2 to be corrected by the calculated correction amount
Further comprising the step of transferring the flexible substrate. The method of claim 11,
The movement speed measurement of the dancer in the step (c1) is performed periodically,
Prior to step c2,
(c20) checking whether the measured speed of the dancer is equal to or greater than a preset reference value
Further comprising:
Performing the steps (c2) and (c3) when the predetermined reference value is equal to or greater than the preset reference value, and stopping the linear velocity correction process when the predetermined reference value is less than the preset reference value
Wherein the flexible substrate transferring and tension control method comprises: The method of claim 11,
The velocity correction amount? V to be applied to the linear velocity v1 or v2 is expressed by the following equation
V = 2 · | v _dancer |
, Where v _dancer is the moving speed of the dancer
Wherein the flexible substrate transferring and tension control method comprises: The method of claim 11,
The change of the position of the dancer,
Detected using a position sensor or detected using the encoder signal of the motor driving the dancer
Wherein the flexible substrate transferring and tension control method comprises:

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