JP6241029B2 - Printing apparatus and printing method - Google Patents

Description

  The present invention relates to a printing apparatus for forming a functional thin film or the like with high quality.

  In recent years, attempts have been made to use a known printing method that is excellent in mass productivity and can reduce the manufacturing cost in forming a fine thin film pattern. In particular, in the display field, in order to cope with an increase in screen size and cost, studies are being made on patterning functional thin films such as organic semiconductors and conductive materials by printing methods.

  Furthermore, among various printing methods, organic semiconductors and conductive materials that use glass as a transfer substrate are not suitable for methods such as gravure printing, which use hard plates such as metal printing plates, and are elastic. An offset printing method using a rubber blanket and a relief printing method using an elastic rubber plate or resin plate are also appropriate. Actually, as an attempt by these printing methods, a method by offset printing (Patent Document 1), a method by letterpress printing (Patent Document 2), and the like have been proposed.

  Among these various printing methods, the resin relief printing method using a relief printing plate made of resin, in particular, includes the relief printing plate, an ink supply roll in which fine recesses (cells) are engraved on the surface called an anilox roll, and a solvent-drying type ink. It is a printing method consisting of the above, and has been widely used for printed materials such as wrapping paper. This resin relief printing method is particularly suitable for forming a thin film having a thickness of about 30 nm to 200 nm.

  In addition, since the resin relief printing method can be printed at a very low printing pressure called kiss touch, it can be applied to a glass substrate or a substrate on which a transparent electrode or the like whose characteristics are easily destroyed by applying high pressure is formed. It is also suitable for printing, and is a printing method particularly suitable for pattern formation of electronic parts such as displays.

  Hereinafter, a general relief printing apparatus 200 will be described with reference to FIG. 6 as an example of a conventional printing apparatus.

  The relief printing apparatus 200 includes an anilox roll 201 having a cell for supplying ink to the plate surface of the relief plate 204, an ink chamber 208 for supplying ink to the anilox roll, and a relief cushion 204 for pattern formation via an under-cushion cushion 203. Is equipped with a rotary plate cylinder 205 on which a printing substrate 207 is mounted, a substrate surface plate 206 on which a substrate 207 to be printed is placed, and a doctor blade 202 that performs doctoring to scrape off ink. The doctor blade 202 may be configured to surround the anilox roll in the closed chamber 209 to prevent drying in the ink chamber of FIG.

  Next, the flow of printing when using the relief printing apparatus 200 of FIG. 6 will be described.

  First, after the substrate to be printed 207 is placed on the substrate surface plate 206, it moves to just below the plate cylinder 205. When the substrate surface plate 206 moves, the plate cylinder 205 rotates synchronously with the operation of the substrate surface plate 206, and ink is supplied to the relief plate 204 from the anilox roll 201 operating at the same speed as the plate cylinder 205. Immediately after the ink is supplied to the relief plate 204, the ink on the relief plate is transferred to the printing substrate 207 and the printing operation is completed.

  Next, the film thickness of the ink and printed matter when printing the high-functional organic material will be described.

  Examples of the ink used as a high-performance material include a polymer organic material, and as described above, the ink has good solubility in an organic solvent, particularly an aromatic organic solvent. Therefore, an ink using an aromatic organic solvent. It is common to use as Among aromatic solvents, solvents with relatively simple addition groups to aromatic rings such as toluene, xylene, anisole, and tetralin are more soluble in organic light-emitting materials, so the solid content concentration of ink is set. Since the degree of freedom is high and there is little risk of precipitation or gelation during use or storage, it is more preferable as a solvent for highly functional organic material inks.

  In addition, organic light emitting material inks using aromatic organic solvents, especially organic light emitting material inks using toluene, xylene, anisole, and tetralin as solvents become liquid inks with low viscosity. The anilox roll method is more suitable.

  The number of fine cells per unit area (cell density) formed on the surface of the anilox roll is generally expressed by the number of lines (the number of cells existing per 1 inch). However, as the number of lines increases, fine cells exist at a high density, so the uniformity of ink transfer to the plate is preferably high, but the volume per cell is small, and the cell volume per fixed area is also small. Therefore, if the number of lines is too high, the absolute amount of ink transfer becomes insufficient. Therefore, by selecting an appropriate number of lines of the anilox roll and setting the solid content ratio of the ink corresponding thereto, an organic film layer having a uniform film thickness can be formed with a target film thickness.

  When patterning highly functional organic inks with high accuracy, the specific number of anilox roll lines and the solid content of the organic light emitting material ink vary depending on the type of the highly functional organic material and the target film thickness. The ink solid content can be adjusted within a range of 1% to 4% using an ink in which a molecular organic light emitting material is dissolved in a toluene or xylene solvent.

  A method for managing the ink solid content ratio in the printing will be described.

  The ink solid content ratio is generally managed by using viscosity. Viscosity is a measure of how quickly an object deforms when a force is applied to an object. When the solids ratio of the polymer is dilute, each polymer chain is in solution. Although it is isolated, it is known that when the solid content ratio of the polymer is increased, the nearby polymer chains are entangled with each other so that they are difficult to rotate and the viscosity is increased. Thus, the solid content ratio and the viscosity value of the polymer are closely related.

  Since the relationship between the solid content ratio and the viscosity mainly shows a cubic curve as shown in FIG. 8, the solid content ratio can be calculated using the viscosity value to manage the film thickness. Further, by using the viscosity value, there is an advantage that the change in the solid content ratio of the ink at the time of printing or after the printing such as the change in the solid content ratio due to the evaporation of the solvent or the state of the ink after printing can be always converted through the viscosity.

  However, since the viscosity value changes depending on the temperature change, it is necessary to measure and manage the temperature. For example, when the temperature of the organic light emitting material in which the organic EL material A is dissolved in the solvent B is increased, the viscosity decreases. When the temperature changes in this manner, the intermolecular force of the ink solvent changes and greatly affects the ink viscosity. Therefore, when the film thickness is controlled by the viscosity value, management for keeping the temperature constant is also necessary.

  In the above-mentioned letterpress printing method, an ink using a relatively highly volatile organic solvent such as toluene or xylene, which is mainly used for high-performance organic materials, is used. Therefore, the solvent easily volatilizes during continuous printing operation. There is a problem in that the solid content of the ink in the ink reservoir (hereinafter referred to as ink chamber) constituting the supply means is gradually increased, and the film thickness of the formed organic film layer is gradually increased.

  Furthermore, since the ink used for the highly functional material is a dispersion of an organic polymer material and is expensive, it is desirable to print the ink with a minimum amount of ink. For this reason, since the total amount of highly functional material ink during printing is small, the change in the solid content ratio with respect to the decrease in the solvent due to evaporation is large, which greatly affects the film thickness.

  For example, when the organic EL material A is dissolved in the solvent B and printed, the viscosity increases by 1 mPa · s due to a change in the solid content ratio of 0.02% by weight. An increase in thickness is observed.

  In the organic EL organic film molding, if the film thickness difference is 10 nm or more in the printing surface, it causes a light emission failure. When converted to a solid content ratio, an increase of 0.08% by weight causes a film thickness difference of 10 nm or more, resulting in poor printing. Therefore, in the functional organic polymer material, the solid content ratio in the ink solution is required to be very severely controlled.

  In order to solve the above problem, a method is proposed in which the amount of evaporation from the ink chamber is calculated from the viscosity value, supplemented, and mixed (Patent Document 3).

  However, in this method, there are at least a viscosity measuring means, a temperature measuring means, and an ink tank for stirring, which must be circulated by a pump, and the total amount of ink must be used in units of several liters. Among them, there is a problem that the amount of ink used increases because a stirring mechanism must be provided using a buffer having a large volume such as an ink tank.

  Since highly functional materials are expensive and it is desirable to minimize the amount used, it is not desirable to increase the amount of liquid in an ink tank or the like.

  In addition, printing of highly functional materials as described above has a large change in the solid content ratio with respect to the decrease in solvent due to evaporation due to a small amount of ink used, and also due to fluctuations in the solid content ratio, the film thickness, shape, unevenness, etc. of the printed matter Therefore, a high replenishment amount resolution and accuracy are required and are very important.

  Therefore, for an expensive high-performance organic material, the change in the solid content ratio due to the decrease in the solvent due to evaporation is large, and a replenishment mixing means for adjusting the solid ratio is necessary. There is a problem that the cost increases because the material utilization efficiency increases and the material utilization efficiency becomes very poor.

JP 2001-93668 A JP 2001-155858 A JP 2009-81107 A

  In view of the above problems, in the present invention, the solid content management of the ink is determined from the increase in viscosity due to factors such as printing for a long time in printing such as printing of a highly functional material using a volatile solvent, A printing device with adjustable ink viscosity that can keep the increase in minutes constant with a small amount of continuous replenishment of solvent, and can continuously print with a small amount of the total amount of ink used at low cost and with a stable film thickness. Provide a printing method.

The invention according to claim 1 has an ink chamber, a circulation path from an ink recovery port provided in the ink chamber to an ink supply port provided in the ink chamber, a circulation pump in the circulation path, and viscosity measurement Means, an ink temperature measuring means, an ink temperature adjusting means, a switching valve and a foreign matter processing filter, a switching valve for replenishing a diluent in the circulation path, and a branch destination of the switching valve Has an ink supply device having a replenisher supply means via a liquid feed pump, and a printing device main body for printing using the ink supplied from the ink supply device, from the ink supply device to the printing device main body. Ink supply is performed by an anilox roll, and the ink recovery port is provided at a position corresponding to two ends of the anilox roll in the longitudinal direction, Serial provided anilox roll longitudinal direction the ink supply port to the center of the ink chamber, to provide a printing apparatus, characterized in that connected to provide a deep groove that connects the ink recovery port and the ink supply port Is.

According to a second aspect of the present invention, when the viscosity measuring means constantly monitors the value of the viscosity and senses that a preset reference viscosity is exceeded, the switching valve opens and closes and the liquid feed pump feeds the liquid. small amount of set time interval by linking the operation, or continuously by feeding the circulation path, if the measured viscosity value falls below a reference viscosity, wherein said liquid feed pump and said switching valve is characterized in that the stop Item 8. A printing apparatus according to Item 1 is provided.

According to a third aspect of the present invention, when the temperature of the ink is constantly monitored by the temperature measuring means of the ink and when it is detected that the difference from the preset reference temperature is exceeded, the temperature of the ink is detected by the temperature adjusting means. The temperature of the ink is not adjusted by the temperature adjusting means when the temperature is less than a difference from a preset reference temperature, and the printing apparatus according to claim 1 or 2 is provided. .

According to a fourth aspect of the present invention, there is provided the printing apparatus according to any one of the first to third aspects, wherein the flow rate of the circulation pump is a flow rate higher than a necessary ink amount per minute. .

Invention of claim 5, wherein the circulation path from said ink recovery port provided in the ink chamber to the ink supply port provided in said ink chamber, claims 1, characterized in that it consists of a sealed 4 A printing apparatus according to any one of the above is provided.

The invention according to claim 6 circulates the ink in a circulation path from the ink recovery port provided in the ink chamber to the ink supply port, and performs ink viscosity measurement, ink temperature measurement, and foreign matter filtering in the circulation path. Ink supply from the ink supply device to the printing device main body using an ink supply device that adjusts the temperature of the ink in the circulation path as necessary and replenishes the diluent in the circulation path as necessary Is performed by an anilox roll, the ink recovery port is provided at a position corresponding to two ends in the longitudinal direction of the anilox roll, the ink supply port is provided at a central position in the longitudinal direction of the anilox roll, and in the ink chamber, A deep groove is provided to connect the ink supply port and the ink recovery port, and the ink supplied through the ink supply port is There is provided a printing method, characterized in that printing with key.

According to the seventh aspect of the present invention, the viscosity value is constantly monitored by the viscosity measurement, and if it is detected that the preset reference viscosity is exceeded, a minute amount is set within the set time interval or continuously in the circulation path. The diluent is supplied to the circulation path, and when the measured viscosity value is lower than the reference viscosity, the diluent is replenished in the circulation path as necessary by stopping the feeding of the diluent. 6 is provided.

According to the eighth aspect of the invention, the temperature of the ink is constantly monitored by measuring the temperature of the ink, and when it is detected that the difference from the preset reference temperature is exceeded, the temperature of the ink is adjusted, and the preset reference is set. If less than the difference between the temperature, by not performing the adjustment of the temperature of the ink at a temperature regulating means, according to claim 6 or 7, characterized in that adjusting the temperature of the ink according to the needs in the circulation path The printing method described is provided.

The invention according to claim 9 is the printing method according to any one of claims 6 to 8 , wherein the flow rate of the ink in the circulation path is a flow rate that is equal to or higher than the required amount of ink per minute.

A tenth aspect of the present invention provides the printing method according to any one of the sixth to ninth aspects, wherein the ink in the circulation path is not brought into contact with outside air.

  As described above, according to the present invention, it is possible to perform continuous printing with a stable film thickness at a low cost while keeping the total amount of ink small.

FIG. 2 is a schematic diagram including a cross-sectional view illustrating a configuration example of a printing apparatus and a circulation path for explaining the present invention. FIG. 5 is a schematic diagram showing a part of a circulation path in a cross-sectional view of an ink chamber which is a configuration example of a printing apparatus for explaining the present invention. FIG. 4 is a schematic diagram showing a part of a circulation path in an internal perspective view of an ink chamber which is a configuration example of a printing apparatus illustrating the present invention. It is a graph which shows the property of the ink used for the Example which concerns on this invention. It is the graph showing the viscosity change and transition amount in the Example of this invention. FIG. 10 is a schematic cross-sectional view illustrating a configuration example of a conventional printing apparatus according to the present invention. It is a schematic cross section showing the example of 1 structure of the conventional printing apparatus based on this invention different from the example of FIG. It is a graph which shows the relationship of the general property of ink.

  The details of the relief printing apparatus according to the embodiment of the present invention when the printing apparatus is a relief printing apparatus will be described below with reference to the drawings. However, it should be noted that the drawings are schematic, and the dimensions and ratios of the members are different from actual ones. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained. In the present embodiment, as shown in FIG. 1, the same parts as those of a conventional relief printing apparatus are denoted by the same reference numerals. The present invention is not limited to this.

  In the letterpress printing apparatus according to the present embodiment and the printing method which is a method for producing a printed material, for example, a pattern in a color filter for a liquid crystal display (LCD), a light emitting layer or a charge transport layer of an organic electroluminescence (EL) element, an organic It can be used for letterpress printing suitable for forming high-definition patterns such as electrode patterns on thin film transistor (TFT) substrates and shield patterns on electromagnetic wave shields.

<Letterpress printing device>
FIG. 1 is a schematic sectional view of a relief printing apparatus 100 showing an embodiment of the present invention. In particular, an ink supply mechanism comprising an anilox roll 101 will be mainly described.

  A relief printing apparatus 100 shown in FIG. 1 has a cylinder-type plate cylinder 105 on which a resin relief plate 104 for pattern formation is mounted, an anilox roll 101 that supplies ink in contact with the relief plate 104, and supplies ink to the anilox roll 101. A circulation path for collecting and supplying ink stored in the ink chamber to the ink viscosity adjusting device 300 and a circulation pump 304, and circulating the ink in the circulation path. Circulation pump 304, viscosity measuring means 302 for measuring the viscosity characteristic value indicating the viscosity of the ink in the ink chamber, ink temperature measuring means 303 for measuring the temperature of the ink, and temperature for keeping the temperature constant The adjusting means 301, the replenisher 307 for replenishing the diluent in the circulation path, and the Ink viscosity adjusting apparatus 300 comprising a key switching valve 305, a liquid feed pump 306 for feeding a replenisher for diluting the ink and adjusting the viscosity, and a foreign matter processing filter 308 for removing foreign matter. A letterpress printing apparatus comprising:

  As an anilox roll 101 that can be used in the relief printing apparatus 100 of the present invention, a chromium oxide film formed by plasma spraying chromium oxide on a core roll made of a stainless steel (hereinafter referred to as SUS) material or the like. Either a ceramic roll patterned by laser engraving, or a chrome roll with copper plating on the core roll and then applying resin after laser patterning, followed by corrosion treatment and chrome plating on the resulting pattern Can also be used. Any pattern such as a helical pattern, FM pattern, honeycomb pattern, diamond pattern, or dot pattern can be used as the pattern formed on the anilocle roll.

  Next, as a doctor roll 102 that can be used, a core roll made of SUS material, etc., nitrile rubber, silicone rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, butyl rubber, acrylonitrile rubber, ethylene propylene A rubber, urethane rubber, or the like may be wound around the rubber roller, or a PFA heat shrinkable tube wound around these rubber rollers may be used. These rubber materials are selected from the resistance to the solvent used as the ink.

  Examples of the solvent for dissolving these functional organic materials include toluene, xylene, acetone, anisole, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetralin and the like alone or a mixed solvent thereof. Of these, aromatic organic solvents such as toluene, xylene, anisole and tetralin are preferred from the viewpoint of solubility of the functional organic material.

  In order to prevent this solvent volatilization, the ink is supplied to an ink fountain with a closed structure called a closed chamber, and the upper part of the anilox roll exposed from the closed chamber is rotated while the lower peripheral surface of the anilox roll is immersed in it. On the peripheral surface, a method of scraping excess ink with a doctor and applying the ink onto the flexographic plate is used.

  Therefore, as a means for suppressing the rise of the ink solid content while reducing the metal foreign matter, for example, as shown in Patent Document 1, using an open type chamber such as a doctor roll 102 method using a rubber roll as a doctor, As shown in Fig. 5, a method of replenishing and mixing the solvent evaporation is proposed.

In the above method, there is no contact with the outside air and solvent volatilization can be prevented.
No. 2 is pressed against the anilox roll in order to push the ink uniformly into the anilox roll cell by scraping off excess ink among the ink applied on the anilox roll 201. For this reason, both the anilox roll and the doctor blade are worn, and there is a problem that the scraped portion is mixed into the ink.

  The anilox roll 201 and the doctor blade 202 are generally made of metal oxide or resin, and are used for printing for electronic members for the purpose of fine patterning of functional thin films such as organic semiconductor thin films and organic EL thin films. , Product failure due to scraped foreign matter. In particular, when the foreign material is a metal, problems such as short-circuiting occur due to electrical conduction. Therefore, in the fine patterning of the functional organic material, a method in which metal foreign matter such as the doctor roll 102 does not come out is required, and the countermeasure of the closed chamber 208 type using a doctor blade is not suitable for use in such applications. It is generally inappropriate unless another measure is taken.

<Ink viscosity adjusting device>
The ink viscosity adjusting apparatus 102 according to the relief printing apparatus of the present invention will be described.

  The present invention is a printing apparatus and printing method that are particularly applicable to functional organic materials in which the change in solid content due to ink evaporation is related to the numerical value of viscosity.

  The ink solid content ratio is generally managed by using viscosity. Viscosity is a measure of how quickly an object deforms when a force is applied to an object. When the solids ratio of the polymer is dilute, each polymer chain is in solution. Although it is isolated, it is known that when the solid content ratio of the polymer is increased, the nearby polymer chains are entangled with each other so that they are difficult to rotate and the viscosity is increased. Thus, the solid content ratio and the viscosity value of the polymer are closely related.

  Since the relationship between the solid content ratio and the viscosity mainly shows a curve as shown in FIG. 9, the solid content ratio can be calculated using the viscosity value to manage the film thickness. Further, by using the viscosity value, there is an advantage that the change in the solid content ratio of the ink at the time of printing or after the printing such as the change in the solid content ratio due to the evaporation of the solvent or the state of the ink after printing can be always converted through the viscosity.

  The ink viscosity measuring means 302 for measuring the viscosity of the ink is preferably a viscosity measuring means that does not change the liquid state with a small amount of liquid used by the viscometer, and examples thereof include a rotary viscometer, a vibration viscometer, Viscosity measuring means such as a ball drop viscometer can be used. Among them, the ink is a viscosity measuring unit 302 that is close to Newtonian fluid and has little influence from the outside, or is non-Newtonian fluid and circulates at a constant flow rate and the measured value is stable. desirable.

  Moreover, since the viscosity value generally changes with changes in temperature, it is necessary to measure and manage the temperature. For example, when the temperature of an organic light emitting material obtained by dissolving the organic EL material A in an anisole solvent is increased by 1 ° C., the viscosity decreases by −0.8 mPa · s. When the temperature changes in this manner, the intermolecular force of the ink solvent changes and greatly affects the ink viscosity. Therefore, when the film thickness is controlled by the viscosity value, management for keeping the temperature constant is also necessary.

  Further, it is desirable that the installation position in the circulation path of the ink temperature measuring device 303 as the temperature measuring means is close to the position of the viscosity measuring device 302 as the ink viscosity measuring means. Further, as the temperature adjusting device 301 which is a temperature adjusting means for keeping the temperature constant, a method of heat dissipation using a heat sink and a cooling fan, air cooling, water cooling, or temperature control using a Peltier element may be used.

  An ink viscosity adjusting apparatus comprising the viscosity measuring means and the temperature measuring means.

  The overall configuration will be described.

  The relief printing apparatus according to the present embodiment includes an ink viscosity adjusting device 304. The ink chamber 108 stores ink and collects and supplies the ink stored in the ink chamber 108 into the viscosity adjusting device 304. A circulation pump 304 that circulates the ink in the circulation path, and a viscosity measuring device 302 that is a viscosity measuring unit that measures a viscosity characteristic value indicating the viscosity of the ink in the ink chamber 108; Ink temperature measuring means 303 which is a temperature measuring means for measuring the temperature of the ink, a temperature adjusting device 301 which is a temperature adjusting means for keeping the temperature constant, and a replenisher for replenishing a diluting liquid in the circulation path A switching valve 305 and a liquid feed pump 30 for feeding a diluent 307 for diluting the ink and adjusting the viscosity. When provided with an ink viscosity at adjusting device 300 having a filter for removing foreign matter, other than the ink chamber 108 is composed of all closed system.

  The ink flow from the ink chamber 108 to the ink viscosity adjusting device will be described.

  The ink in the ink chamber 108 is collected into the ink viscosity adjusting device by the circulation pump 304 and measured by the viscosity measuring device 302 and the temperature measuring device 301 in the circulation system of the device, and the difference between the value and the set value is measured. When the ink viscosity rises, a signal is generated from the viscosity measuring means in the circulation system, and the switching valve and the liquid feed pump 306 operate in conjunction with each other, and a small amount of the diluent 307 is continuously added. By doing so, the viscosity of the whole ink is lowered. That is, by adjusting the viscosity, the ink whose solid content has been adjusted is re-supplied into the ink chamber 108, thereby making it possible to make the film thickness constant during continuous printing.

  In this operation, the recovery operation of the ink from the ink chamber 108 to the ink viscosity adjusting device 300 and the supply operation to the ink chamber 108 are repeated by the circulation pump 304, and the viscosity measurement means with excellent response speed in measuring the ink viscosity. Monitoring is always performed at 302, and in response to a minute change in viscosity, a small amount of diluent is continuously supplied by a liquid feed pump 306 or a minute amount of diluent is replenished at set time intervals. Therefore, it is possible to control the solid content distribution of the ink in the ink circulation system with high accuracy with a minimum stirring time.

  The liquid feed pump 306 for replenishing the diluent 307 is required to continuously replenish a minute amount of the diluent according to the change in viscosity. Although the evaporation rate varies depending on the opening area of the ink chamber and the amount of ink, the replenishment speed is required to be faster than the evaporation amount. Specific examples of the liquid feed pump 306 include a diaphragm pump, a plunger pump, and a syringe pump.

  The switching valve 305 for mixing the diluent with the ink in the circulation path uses a valve such as an air operated valve or a solenoid valve, and opens and closes in conjunction with the operation of the liquid feed pump 306. The switching valve 305 is preferably a diaphragm type valve having a small contact area with the diluent in order to prevent contamination due to liquid residue.

  Further, since the diluting solution is continuously replenished in a small amount, there is an advantage that the solid content concentration of the entire ink is easily maintained because it is easily diffused throughout the ink.

For the circulation pump 304 that plays the role of mixing and stirring the ink in the circulation system and the diluting liquid 307, the circulation amount should be large, and at least the circulation flow rate is preferably the necessary ink amount per minute. If it is not clear, the ink chamber volume is preferred instead. However, when a pump with a large amount of circulating fluid is used, the temperature change accompanying the heat generation of the motor and the increase of the fluid pressure becomes large, which greatly affects the viscosity. For this reason, an air-driven diaphragm pump or a small motor-type diaphragm pump that has little influence on heat is desirable.

  In addition, a diaphragm pump in which a high-functional material does not rub or come into contact with an operation part during a liquid feeding operation is more preferable than foreign matters mixed therein.

  Furthermore, since the dilution liquid 307 is continuously replenished with a very small amount, it is easy to be diffused, and there is an advantage that the density uniformity of the entire ink is maintained. The ink supply port 310 from the ink viscosity adjusting device 300 and the ink recovery port 309 to the ink viscosity adjusting device 300 are connected by a deep groove, and the positions of the ink recovery 309 are two locations on both ends of the anilox roll 101 in the longitudinal direction. The position of the ink supply port 310 is preferably the center position of the ink chamber 108.

  FIG. 2 shows the ink flow in the ink chamber.

  By digging a deep groove from the ink supply port to the ink collection port, ink is injected from the central ink supply port of the ink chamber and flows toward the ink collection port through the deep groove. Thereby, the solid content concentration in the ink chamber can be made uniform.

  The shape of the deep groove is required that the supplied ink spreads by capillary action through the groove and the anilox roll. Therefore, it is desirable that the supply port, the recovery port, and the groove of the ink chamber are in a position closest to the anilox roll.

  The width of the groove of the ink chamber is defined as a position where a perpendicular is dropped from a position of 1 ° or more and less than 20 ° to the left and right from a line straight line connecting the anilox roll and the closest portion of the chamber to the axis of the anilox roll. .

  The depth of the deep groove is required to flow sideways before the ink coming out of the supply port contacts the anilox roll, and since the amount of the ink accumulated in the groove is required to be small, A volume of 2% to 10% or less is desirable.

  FIG. 3 shows the ink flow on the anilox scraped by the doctor roll.

  The ink on the anilox roll 101 scraped by the doctor roll accumulates at the contact point between the anilox roll and the doctor roll, and gradually flows toward the end of the anilox roll. Since the ink finally accumulates at the end portion in the ink chamber, the ink recovery port 309 needs to be installed at the end portion of the ink chamber.

  For these reasons, the ink chamber having the above-described structure increases the fluidity of the ink in the ink chamber 108, and the solid content concentration in the ink chamber 108 can be kept uniform.

  As control means for replenishing a specific diluent 307 such as a solvent, a liquid feed pump 306 capable of automatically controlling the amount of solvent replenishment and a switching valve 305 for supplying the solvent into the circulation path are installed. The viscosity measuring device 302 installed in the circulation system has means for outputting the viscosity information to the outside, and the liquid feed pump 306 for replenishing the solvent in the circulation system sends the replenishment liquid and its timing from the outside. The viscosity measuring device 302 and the liquid feed pump 306 are configured to output a replenishment amount and timing of the liquid feed pump 306 based on the viscosity information input from the viscosity measuring device 302. It is electrically connected to a computer having a program.

  In addition, since the ink replenishment timing can be automatically controlled based on the result of measuring the viscosity of the ink, it is possible to circulate below the upper limit of the viscosity to be controlled by setting a viscosity value that gives a solvent replenishment command signal. It is possible to control the ink viscosity in the path.

  By performing the above operation, the total amount of ink can be reduced to a small amount, and continuous printing with a stable film thickness can be achieved at low cost.

  Examples of the present invention will be described below. In addition, this invention is not limited to an Example, The improvement, deformation | transformation, etc. in the range which can achieve this invention do not deviate from the meaning of this invention.

<Example 1>
Examples of the present invention will be specifically described below.

  In Example 1, a light emitting layer was formed by a relief printing method using an organic EL ink in which an organic light emitting material was dissolved in a solid content ratio of 1.83% as the solvent A.

  The solid content ratio and viscosity relationship of the ink are shown in FIG.

  Moreover, the used printing apparatus has the ink supply means having the configuration and function shown in the above-described embodiment, and a printing apparatus of a type that prints on a flat substrate such as a glass substrate with a sheet is used. In the evaluation method, the amount of ink transferred to the glass was defined as the transfer amount, and the thickness and width of the transferred ink were measured using an interference film thickness meter, and the cross-sectional area was evaluated.

  As the anilox roll 101, a chromium plating roll having a surface length of 200 mm was used.

  The doctor roll 102 was pushed into the anilox roll 101.

  Regarding the ink viscosity adjusting device, an ink chamber having an ink recovery port at both ends in the longitudinal direction, an ink supply port at the center, and a structure in which the ink supply port and the ink recovery port are connected by a deep groove having a width of 10 mm was used. The total ink usage volume in the ink chamber was 100 to 500 ml.

  As the circulation pump, a diaphragm pump having an ink chamber flow rate of 100 to 500 ml / min was used.

<Viscosity measurement method>
As a viscosity measuring apparatus, an in-line torsional vibration viscometer having no self-heating and excellent in high-accuracy responsiveness was used, and the volume necessary for measurement was 20 ml.

  The switching valve is a diaphragm type air operated valve, and as the temperature control device 301, a cooling method using heat radiation by a jig using a copper plate, a heat sink and a cooling fan is used.

The viscosity of the ink in the ink chamber during printing is controlled at a range of 38 mPa · s to 40 mPa · s centering on 39.0 mPa · s, and the viscosity for replenishing the solvent is set to 39 mPa · s. Then, automatic viscosity control of the ink was performed. The amount of solvent replenishment at one time was 0.4 ml, and it was set to replenish when the viscosity in the ink chamber did not fall below the initial viscosity of 38 mPa · s within 2 seconds after the solvent was dropped. The lower limit alarm for viscosity was set to be issued at 38 mPa · s.

By setting the ink viscosity control conditions as described above, printing was continued for 3 hours, and the ink viscosity in the ink chamber could be controlled within the target range of 38.5 mPa · s to 39.5 mPa · s. . Moreover, the transfer amount of the light emitting layer after printing could be controlled in the range of 2.95 μm ² to 2.96 μm ² from the stable region.

<Comparative example>
In the comparative example, printing was performed continuously 25 times for 3 hours without controlling the viscosity of the ink in the ink chamber during printing under the same conditions as in Example 1. The ink viscosity in the ink chamber during printing was actually increased from 38.5 mPa · s to 50.1 mPa · s and 11.5 mPa · s. Further, the transfer amount of the light-emitting layer after printing rose greatly 2.95μm ² ~3.01μm ² from the stable region.

  The measured values of the comparative example and the example are shown in FIG.

DESCRIPTION OF SYMBOLS 101: Anilox roll 102: Doctor roll 103: Under-cushion cushion 104: Letterpress 105: Plate cylinder 106: Substrate surface plate 107: Substrate to be printed 108: Ink chamber 208: Closed chamber 300: Viscosity adjustment device 301: Temperature adjustment device 302: Viscosity measuring device 303: Temperature measuring device 304: Circulation pump 305: Switching valve 306: Liquid feed pump 307: Diluent 308: Filter 309: Ink recovery port 310: Ink supply port

Claims (10)

  An ink chamber, and a circulation path from an ink recovery port provided in the ink chamber to an ink supply port provided in the ink chamber, and a circulation pump, a viscosity measurement means, and an ink temperature measurement means in the circulation path And a temperature control means for ink, a switching valve and a foreign matter processing filter, a switching valve for replenishing the diluent in the circulation path, and a branching point of the switching valve via a liquid feed pump An ink supply device having a replenisher supply means and a printing device main body for printing using the ink supplied from the ink supply device, and ink supply from the ink supply device to the printing device main body is performed by an anilox roll. The anilox roll is provided with the ink recovery port at positions corresponding to the two ends in the longitudinal direction of the anilox roll. Hand direction in a central position the ink supply port is provided in the in the ink chamber, the printing apparatus characterized in that it is connected to provide a deep groove that connects the ink recovery port and the ink supply port.   When the viscosity measurement means constantly monitors the viscosity value and senses that a preset reference viscosity has been exceeded, a small amount is set by linking the opening / closing operation of the switching valve and the liquid feeding operation of the liquid feeding pump. 2. The printing apparatus according to claim 1, wherein when the liquid is supplied to the circulation path at time intervals or continuously and the measured viscosity value is lower than a reference viscosity, the switching valve and the liquid supply pump are stopped.   When the temperature of the ink is constantly monitored by the temperature measuring means of the ink and it is detected that the difference from the preset reference temperature is exceeded, the temperature of the ink is adjusted by the temperature adjusting means, and the preset reference is set. 3. The printing apparatus according to claim 1, wherein when the temperature difference is less than the temperature, the temperature adjustment means does not adjust the temperature of the ink.   4. The printing apparatus according to claim 1, wherein the flow rate of the circulation pump is a flow rate that is equal to or higher than a necessary ink amount per minute.   5. The printing apparatus according to claim 1, wherein the circulation path is configured to be sealed from an ink recovery port provided in the ink chamber to an ink supply port provided in the ink chamber. Ink is circulated through a circulation path from the ink recovery port provided in the ink chamber to the ink supply port. In the circulation path, ink viscosity is measured, ink temperature is measured, and foreign matter is filtered. Ink supply from the ink supply device to the printing device main body is performed by an anilox roll using an ink supply device that performs temperature adjustment in the circulation route and supplements the diluent in the circulation route as necessary. The ink recovery port is provided at a position corresponding to two positions on both ends in the longitudinal direction of the anilox roll, the ink supply port is provided at a central position in the longitudinal direction of the anilox roll, and the ink supply port and the ink recovery are provided in the ink chamber. A deep groove is provided to connect the mouth, and printing is performed using ink supplied through the ink supply port. Printing method was characterized by.   When the viscosity value is constantly monitored in the viscosity measurement and it is detected that the preset reference viscosity has been exceeded, a small amount of the diluent is sent into the circulation path at a set time interval or continuously, The printing method according to claim 6, wherein when the measured viscosity value is lower than the reference viscosity, the diluent is replenished in the circulation path as necessary by stopping the feeding of the diluent.   When the temperature of the ink is constantly monitored by measuring the temperature of the ink, and when it is detected that the difference from the preset reference temperature is exceeded, the temperature of the ink is adjusted, and when the difference is less than the preset reference temperature, 8. The printing method according to claim 6, wherein the temperature of the ink is adjusted in the circulation path as necessary by not adjusting the temperature of the ink by the temperature adjusting means.   9. The printing method according to claim 6, wherein the flow rate of the ink in the circulation path is a flow rate that is equal to or higher than a necessary amount of ink per minute. The printing method according to claim 6, wherein the ink in the circulation path is not brought into contact with outside air.

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