JP6692038B2 - Ink supply device for flexographic printing - Google Patents

Description

  The present invention relates to an ink supply device for flexographic printing that forms a transparent electrode film on a substrate using, for example, a transparent conductive polymer ink.

  Transparent electrode films that transmit light are widely used in the fields of organic EL lighting, solar cells, liquid crystal display devices, touch panels, and the like. As a transparent electrode used in this field, an indium oxide compound (ITO) doped with tin is widely used because it has excellent transparency and relatively good electric characteristics (conduction characteristics). ..

However, most of the above-mentioned indium (In) production in the world depends on one producing country, and ITO is adopted as a countermeasure against the resource soaring due to the ubiquity of producing countries and the limitation of the number of years of harvest. Practical use of alternative transparent electrode materials is urgent.
In addition, a vapor deposition method is generally used for forming the transparent electrode film using this ITO. However, since this uses a vacuum process, the equipment is large and the equipment cost rises, and there are many wastes of raw materials. Costs will inevitably increase as problems overlap.

  Further, the above-mentioned transparent electrode made of ITO can be said to be a kind of ceramics so to speak, and has a brittle property, so that there is a limit in using it for a flexible device. Therefore, the appearance of a transparent electrode film having a practical stress resistance corresponding to a flexible device is desired.

Therefore, recently, for example, a proposal has been made to form a light emitting layer or a transparent conductive film by printing an ink obtained by dissolving a polymer organic EL light emitting material in a solvent or a transparent conductive polymer ink on a substrate. There is.
For example, Patent Document 1 discloses an example of printing a light emitting layer of an organic EL element on a base material using a flexographic printing technique.

JP, 2009-59496, A

  By the way, in the flexographic printing described above, anilox roll is used as an ink supply means. In this anilox roll, for example, a mesh-shaped groove is formed on the peripheral side surface (cylindrical surface) of the roll, and after immersing the anilox roll in ink, excess ink is scraped off with a sharp blade (doctor blade). .. As a result, the ink is filled in the groove of the anilox roll, and the filled ink operates so as to be transferred to the flexographic printing plate.

FIG. 3 shows a basic configuration of a conventional flexographic printing apparatus, and FIG. 4 shows an example of a mesh-shaped groove formed on the peripheral side surface (cylindrical surface) of an anilox roll.
As shown in FIG. 3, the lower bottom part of the anilox roll 1 arranged so that the axial direction is horizontal is capable of rotating the shaft while being immersed in the ink IK stored in the ink storage tank 2. Is located in.
Then, the anilox roll 1 contacts a part of the flexographic printing plate 3 attached to the peripheral side surface of the plate cylinder 4, and is rotationally driven together with the plate cylinder 4 in the directions shown by the arrows. At this time, the anilox roll 1 and the plate cylinder 4 rotate in the same direction and at the same speed.

  The surface of the anilox roll 1 is provided with mesh-shaped grooves as shown in FIG. 4. In the example shown in FIG. 4 (A), hexagonal grooves are regularly arranged to form a honeycomb pattern. ing. Further, in the example shown in FIG. 4B, the square grooves are regularly arranged so as to intersect in the 45 ° direction. Further, in the example shown in FIG. 4 (C), the stripe-shaped grooves are arranged in the direction of an angle of 45 degrees.

As shown in FIG. 3, a doctor blade 5 is arranged between the ink storage tank 2 and the flexographic printing plate 3 in the rotation direction of the anilox roll 1, and the excess ink attached to the surface of the anilox roll 1 is removed. Is scraped off by the doctor blade 5, and the ink required for printing is filled in the groove of the anilox roll 1.
Then, the ink filled in the groove of the anilox roll 1 is transferred to the flexographic printing plate 3 by coming into contact with the flexographic printing plate 3.

That is, the ink corresponding to the volume of the groove formed on the anilox roll 1 is transferred to the flexographic printing plate 3.
On the other hand, the impression cylinder 6 urged toward the flexographic printing plate 3 is arranged, and the printing substrate BM interposed between the flexographic printing plate 3 and the impression cylinder 6 is the rotation of the flexographic printing plate 3. According to the printing method, the printing is carried out in accordance with the printing pattern applied to the flexographic printing plate 3 while being sent out by the rotary printing method.

  By the way, in the above-mentioned flexographic printing apparatus, when the ink supply system using anilox roll is used as it is for printing for making a device, a defect such as deterioration may occur in a completed device, and in particular, deterioration may occur. It has been found that problems are likely to occur when using an easy-to-use ink.

This problem has been verified, for example, in the process of manufacturing an organic EL lighting device, particularly when a transparent conductive film is formed on a substrate using a transparent conductive polymer ink.
The transparent conductive polymer ink has a low viscosity and a low concentration, and is easy to deposit (aggregate) on an anilox roll or form a gel. It has been confirmed that the gel and the foreign matter generated in the ink result in significant deterioration of characteristics such as an increase in leak current in the organic EL lighting device and generation of dark spots (non-light emitting portions).

That is, in the anilox roll used for flexographic printing, the ink remains in the groove, and the residual ink is kneaded many times, resulting in gel etc. in the ink, and when the device is manufactured after printing. It is assumed that the quality of the device deteriorates as shown in the above example.
Further, it is considered that the anilox roll is constantly rotating, and that the ink stored in the ink storage tank, in which a part of the anilox roll is immersed, is likely to be deteriorated in quality due to the above-described deterioration in quality.

  Further, in printing ink with low viscosity and low concentration, in general ink supply of flexographic printing, there is a problem that a solid content transferred to a printing plate is too small and a film cannot be formed. Moreover, the ink transfer rate from the anilox roll to the printing plate is not very large.

  The present invention has been made by paying attention to the occurrence of the above-mentioned inconvenience that occurs in a device created by flexographic printing using anilox rolls, and is particularly susceptible to alteration by improving the ink supply means using anilox rolls. An object of the present invention is to provide an ink supply device for flexographic printing, which can eliminate the occurrence of defects in devices even when ink is used.

A preferred first mode of the ink supply device for flexographic printing according to the present invention, which is made to achieve the above-mentioned problems, is that the linear end portions of the two plate bodies facing each other are arranged side by side, A linear slit is formed at the tip, and the ink supplied between the two plate bodies is configured to be discharged from the linear slit, and the peripheral side surface is formed smoothly. And an ink supply roller that receives the ink ejected from the linear slit of the ink supply unit so that the peripheral side surface has a predetermined coating thickness while rotating, and an ink supply that has a predetermined coating thickness. The flexographic printing plate that comes into contact with the ink supply roller that receives the ink is attached to the peripheral side surface, and the ink received from the ink supply roller is printed by the flexographic printing plate. A plate cylinder for pivoting perform transfer for the than the contact position of the flexographic printing plate in the ink supply roller is disposed at a position after the rotating direction of the ink supply roller, in contact with the peripheral surface of the ink supply roller , A doctor blade for removing the transfer residual ink to the flexographic printing plate from the peripheral side surface of the ink supply roller, and for the ink supply roller in a state where the transfer residual ink is removed from the ink supply unit Is supplied, and the rotation directions of the ink supply roller and the plate cylinder are the same when viewed from the respective rotation axis directions.

In a preferred second embodiment of the ink supply device for flexographic printing according to the present invention, a gap is formed between an ink supply roller whose peripheral side surface is formed smooth and is axially rotated, and the peripheral side surface of the ink supply roller. By providing the ink storage portion between the formed and arranged chamber blade, the ink in the ink storage portion has a predetermined coating thickness on the peripheral side surface of the ink supply roller as the shaft of the ink supply roller rotates. The flexographic printing plate that comes into contact with the ink supply unit that supplies the ink and the ink supply roller that receives the ink so as to have a predetermined coating thickness is attached to the peripheral side surface, and the ink received from the ink supply roller is From the axially rotating plate cylinder that transfers to the substrate to be printed by the flexographic printing plate, and the contact position of the ink supply roller to the flexographic printing plate A doctor blade is provided at a rear position in the rotation direction of the ink supply roller, which contacts the peripheral side surface of the ink supply roller and removes the ink remaining after transfer to the flexographic printing plate from the peripheral side surface of the ink supply roller. The ink from the ink supply unit is supplied to the ink supply roller in which the transfer residual ink has been removed , and each rotation when viewed from the rotation axis direction of the ink supply roller and the plate cylinder. It is characterized in that the directions are the same.

  In any of the first and second embodiments, preferably, the ink remaining after transfer to the flexographic printing plate recovered by the doctor blade is reprocessed and supplied to the ink supply unit. Is composed of.

  In addition, it is desirable that the surface of the ink supply roller having a smooth peripheral surface be formed of ceramics or diamond dry carbon.

In addition, by making the rotation directions of the ink supply roller and plate cylinder respectively the same when viewed from the rotation axis direction , it is possible to transfer ink with a thick wet film thickness as flexographic printing from the ink supply roller to the printing plate. Become.
Further, the amount of ink supplied to the printing plate can be changed by controlling the peripheral speeds of the ink supply roller and the plate cylinder.

  According to the flexographic printing ink supply device of the present invention described above, as the ink supply roller for receiving the ink from the ink supply unit, a roller (flat roller) having a smooth peripheral surface is used instead of the anilox roller. .. Then, the ink remaining on the flexographic printing plate after being transferred from the ink supply roller is scraped off by a doctor blade, and the ink from the ink supply unit is supplied to the ink supply roller in a state where the remaining transfer ink is removed. Acts as if it were.

Therefore, new ink is always supplied to the ink supply roller from the ink supply unit, and new ink is constantly supplied to the flexographic printing plate through the ink supply roller, so that the flexographic printing plate is supplied to the substrate to be printed. Printing is performed.
Therefore, according to the present invention, it is possible to prevent the ink agglomeration and the like as described above even when using an ink that is particularly susceptible to deterioration, and thereby eliminate the occurrence of defects in the device. A device can be provided.

It is the schematic diagram which showed the 1st form of the ink supply apparatus for flexographic printing which concerns on this invention. It is a schematic diagram which similarly showed the 2nd form. It is the schematic diagram which showed an example of the flexographic printing apparatus using the conventional anilox roller. It is a front view showing an example of arrangement of grooves formed in a conventional anilox roller.

  A flexographic printing ink supply device according to the present invention will be described based on an embodiment shown in the drawings. In addition, in this embodiment, a case where printing is performed on a substrate using a transparent conductive polymer ink in order to form the transparent conductive film of the organic EL lighting device will be described as an example. The supply device can obtain the same operation and effect even when performing flexographic printing using another ink that is easily deteriorated.

FIG. 1 shows a first embodiment. In the flexographic printing ink supply device shown in FIG. 1, an ink supply unit having a linear slit formed at its tip is used.
That is, in the ink supply unit 11, the linear end portions of the upper first plate body 12a and the lower second plate body 12b facing each other are arranged side by side so that the linear shape is formed at the front end portion. Slits 13 are formed. Then, the ink supplied between the first and second plate bodies 12a and 12b is configured to be ejected from the linear slit 13.

The ink IK from the ink reservoir 21 is sent to the ink supply unit 11 by a pump 22.
In addition, the ink supply roller 16 is arranged with a slight gap to the linear slit 13 of the ink supply unit 11, and both are arranged so that the longitudinal direction of the slit 13 and the axial direction of the ink supply roller 16 coincide with each other. Are arranged.

The peripheral surface (roller surface) of the ink supply roller 16 is formed to be smooth, and the ink supply roller 16 preferably has a structure in which ceramics or diamond dry carbon is arranged on the surface.
Further, the ink discharged from the linear slit 13 in the ink supply unit 11 is applied to the ink supply roller 16 so as to have a predetermined coating thickness on the peripheral side surface of the ink supply roller 16 which rotates axially in the arrow direction. Supplied to As a result, an ink coating film is formed on the peripheral side surface of the ink supply roller 16 so as to receive the ink from the ink supply unit 11 and preferably have a coating thickness in the range of 1 to 10 μm.

Reference numeral 17 is a flexographic printing plate attached to the peripheral side surface of the plate cylinder 18, and the plate cylinder 18 provided with the flexographic printing plate 17 is rotated independently of the ink supply roller 16. That is, as indicated by the arrow indicating the direction of rotation, the ink supply roller 16 is driven to rotate right in FIG. 1, and the plate cylinder 18 is also driven to rotate right.
That is, the moving direction of the peripheral side surface of the ink supply roller 16 facing each other and the moving direction of the flexographic printing plate 17 attached to the plate cylinder 18 are opposite to each other. As a result, the ink on the peripheral side surface of the ink supply roller 16 is transferred to the flexographic printing plate 17 while being rubbed against the flexographic printing plate 17.

As described above, by making the rotation directions of the ink supply roller 16 and the plate cylinder 18 respectively the same when viewed from the rotation axis directions , the ink supply roller 16 and the printing plate 17 have a thick wet film thickness for flexographic printing. It is possible to transfer the ink.
In this case, by further controlling the peripheral speeds of the ink supply roller 16 and the plate cylinder 18, the amount of ink supplied to the printing plate 17 can be changed.

  On the other hand, an impression cylinder 19 urged toward the plate cylinder 18 is arranged, and the substrate BM to be printed interposed between the impression cylinder 19 and the flexographic printing plate 17 is rotated by the plate cylinder 18. Therefore, it is sent out in the direction of the arrow by the rotary method. At this time, printing is performed on the base material BM to be printed by transfer of ink according to the print pattern applied to the flexographic printing plate 17.

A doctor blade 23 that comes into contact with the peripheral side surface of the ink supply roller 16 is provided at a position rearward of the position where the ink supply roller 16 contacts the flexographic printing plate 17 in the rotation direction of the ink supply roller 16. The doctor blade 23 has a function of removing the ink remaining after the transfer to the flexographic printing plate 17 from the peripheral side surface of the ink supply roller 16.
That is, new ink is always supplied from the ink supply unit 11 to the ink supply roller 16 in which the untransferred ink has been removed by the doctor blade 23.

As a result, new ink from the ink supply unit 11 is applied to the plate cylinder 18, and printing by transfer is performed on the printing substrate BM using this ink.
Therefore, in this flexographic printing, even in the case of using an ink that easily deteriorates, which is typified by the transparent conductive polymer ink described above, it is possible to effectively increase the leakage current and the occurrence of defects such as dark spots, which are already described in the device. Can be suppressed.

In the example shown in FIG. 1, the transfer residual ink collected by the doctor blade 23 is reprocessed through, for example, the viscosity / concentration adjusting means 24 and the filtering means 25, and is stored in the ink storage tank 21. It is configured to be returned and reused.
The ink reservoir 21 is preferably configured so that supplementary ink is appropriately supplied through the opening / closing valve 26.

  Further, in the example shown in FIG. 1, the ink supply unit 11, the ink supply roller 16 and the doctor blade 23 described above constitute a unit, and the ink supply roller 16 is a flexographic printing plate 17 provided on a plate cylinder 18. It is configured to be able to approach or separate from. That is, when the ink supply roller 16 approaches the flexographic printing plate 17, the printing operation state (state shown in FIG. 1) is achieved, and the ink supply roller 16 moves from the flexographic printing plate 17 together with the ink supply unit 11 and the doctor blade 23. By leaving, the print standby state is set.

  In this case, in the print standby state, the ink supply roller 16 is preferably rotated so that the peripheral speed is 1 to 5 m / min. Further, in the printing operation state, the peripheral speed of the ink supply roller 16 is preferably set to 1 to 15 m / min.

FIG. 2 shows a second embodiment of a flexographic printing ink supply device according to the present invention. Note that, in FIG. 2, portions that perform the same functions as the respective portions shown in FIG. 1 are denoted by the same reference numerals, and therefore description thereof will be omitted as appropriate.
In the second embodiment, the ink supply unit 11 that supplies ink to the ink supply roller 16 having a smooth peripheral surface forms a gap between the ink supply roller 16 and the peripheral surface of the ink supply roller 16. The chamber blades 14 are arranged in the same manner.

  That is, as shown in FIG. 2, the chamber blade 14 is disposed so as to be inclined such that the other end thereof is obliquely upward with respect to the front end facing the ink supply roller 16. Then, an ink reservoir 15 is formed between the ink supply roller 16 and the upper surface of the chamber blade 14, and the ink IK from the ink reservoir 21 is fed into the ink reservoir 15 by the pump 22. Thereby, a certain amount of ink is stored in the ink storage section 15.

With this configuration, the ink ejected from the gap between the chamber blade 14 and the ink supply roller 16 in the ink supply unit 11 has a predetermined coating thickness on the peripheral side surface of the ink supply roller 16 that rotates axially in the arrow direction. As described above, the ink is supplied to the ink supply roller 16.
As a result, an ink coating film can be formed on the peripheral side surface of the ink supply roller 16 so as to have a coating thickness in the range of 1 to 30 μm in a wet state.

  The chamber blade 14 is configured to be movable in the surface direction with respect to the ink supply roller 16, and if necessary, the gap between the ink supply roller 16 and the chamber blade 14 is closed so that the ink supply roller 16 is closed. The ink supply to 16 can be stopped.

The second embodiment shown in FIG. 2 is different from the first embodiment shown in FIG. 1 in that the ink supply unit 11 having the chamber blade 14 described above is provided, and other configurations are the same as those of the first embodiment. It is the same as the embodiment.
Therefore, also in the second embodiment, it is possible to obtain the same effect as that of the first embodiment described above.

  In the embodiment described above, an example is shown in which the ink supply device of the present invention is applied to a rotary flexographic printing device, but the ink supply device of the present invention is disclosed in the above-mentioned Patent Document 1. Needless to say, it can be applied to a single sheet-type flexographic printing apparatus.

11 Ink Supply Unit 12a First Plate 12b Second Plate 13 Slit 14 Chamber Blade 15 Ink Storage Section 16 Ink Supply Roller 17 Flexographic Printing Plate 18 Plate Cylinder 19 Pressure Cylinder 21 Ink Storage Tank 22 Pump 23 Doctor Blade 24 Viscosity / Concentration Adjustment means 25 Filtration means 26 Open / close valve IK Ink BM Printed substrate

Claims (4)

By arranging the linear end portions of the two plate bodies facing each other side by side, a linear slit is formed at the tip portion, and the ink supplied between the two plate bodies is the straight line Ink supply unit configured to be discharged from a slit
An ink supply roller whose peripheral side surface is formed to be smooth, and which receives ink ejected from a linear slit in the ink supply unit while axially rotating so as to have a predetermined coating thickness on the peripheral side surface,
A flexographic printing plate that comes into contact with an ink supply roller that has been supplied with ink to a predetermined coating thickness is attached to the peripheral side surface, and the ink received from the ink supply roller is applied to a substrate to be printed by the flexographic printing plate. An axially rotating plate cylinder that performs transfer to
It is arranged at a rear position in the rotation direction of the ink supply roller rather than the contact position on the flexographic printing plate in the ink supply roller, contacts the peripheral side surface of the ink supply roller, and transfers residual ink to the flexographic printing plate. , Equipped with a doctor blade to remove from the peripheral surface of the ink supply roller,
The ink from the ink supply unit is supplied to the ink supply roller from which the transfer residual ink has been removed, and the respective rotation directions when viewed from the rotation axis directions of the ink supply roller and the plate cylinder are Ink supply device for flexographic printing characterized by being the same . By providing an ink storage portion between the ink supply roller that has a peripheral side surface formed to be smooth and is axially rotated, and a chamber blade that is arranged with a gap formed between the peripheral side surface of the ink supply roller, An ink supply unit that supplies the ink in the ink reservoir with the shaft rotation of the ink supply roller so that the peripheral surface of the ink supply roller has a predetermined coating thickness;
A flexographic printing plate that comes into contact with an ink supply roller that has been supplied with ink so as to have a predetermined coating thickness is attached to the peripheral side surface, and the ink received from the ink supply roller is printed by the flexographic printing plate. An axially rotating plate cylinder that transfers to
It is arranged at a rear position in the rotation direction of the ink supply roller rather than the contact position on the flexographic printing plate in the ink supply roller, contacts the peripheral side surface of the ink supply roller, and transfers residual ink to the flexographic printing plate. , Equipped with a doctor blade to remove from the peripheral surface of the ink supply roller,
The ink from the ink supply unit is supplied to the ink supply roller from which the transfer residual ink has been removed, and the respective rotation directions when viewed from the rotation axis directions of the ink supply roller and the plate cylinder are Ink supply device for flexographic printing characterized by being the same . 3. The flexographic printing apparatus according to claim 1, wherein the ink remaining after transfer to the flexographic printing plate collected by the doctor blade is reprocessed and supplied to the ink supply unit. Ink supply device for printing. The surface of the peripheral side surface is smoothly formed by said ink supply roller, flexographic ink supply device according to any one of claims 1 to 3, characterized in that it is more formed on ceramics ..

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