JP2010036421A - Printing method and printing press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing method and a printing press suitable for the printing method which can perform stable and excellent printing without limiting kinds of a rubber layer and a solvent without affecting printing quality, and furthermore, as accurately as possible while quantifying the solvent which swells the rubber layer of a blanket. <P>SOLUTION: The printing method measures Raman scattered light generated when the rubber layer of the blanket is irradiated with a laser beam and quantifies the solvent of ink which has been soaked into the rubber layer from the gap of a frequency of irradiation light and scattered light, and based on this result, removes the solvent soaked into the rubber layer. The printing press 1 is equipped with the solvent quantifying section 8 which measures Raman scattered light generated when the rubber layer of the blanket 2 is irradiated with a laser beam, and from the gap of frequency of irradiation light and scattered light, quantifies the solvent of ink soaked into the rubber layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing method for printing by transferring ink carried on the surface of a rubber layer of a blanket to the surface of a printing medium, and a printing machine used for the printing method.

  For example, a pattern having a very fine line width compared to the area of the substrate, such as an electrode on the front plate of a plasma display panel, an electromagnetic wave shield, or a color filter layer of a liquid crystal display panel, is formed on almost the entire surface of the substrate. Conventionally, a formation method using a so-called photolithographic method has been adopted. However, in recent years, in order to form the pattern in a short time and with good productivity in order to reduce the number of processes as much as possible, to reduce the energy consumption, to reduce the waste of materials used, and to improve productivity in a short period of time, in place of the photolithographic method, The use of an offset printing method is being studied.

  In the intaglio offset printing method, an intaglio having recesses corresponding to the pattern was prepared, and after filling the recesses of the intaglio with ink, a rubber layer constituting at least the surface of the ink was formed of silicone rubber or the like A blanket is transferred to the surface of the rubber layer. Then, the ink is re-transferred to the surface of the substrate and then baked, whereby a pattern corresponding to the pattern of the recesses of the intaglio is formed on the surface of the substrate.

According to such an intaglio offset printing method, for example, by forming a concave portion of an intaglio plate by a photolithographic method, it has a high accuracy almost equivalent to that formed by a photolithographic method directly on the surface of a conventional glass substrate. A pattern can be formed.
The photolithographic method requires a number of steps to form a pattern and also forms a pattern by combining etching and plating using a mask pattern. It is necessary to use a large amount of the photosensitive resin or the like that exceeds the amount required by the pattern to be actually formed. Moreover, it is difficult to collect and reuse a large amount of waste material generated by etching or the like individually.

  In contrast, the intaglio offset printing method allows the intaglio and blanket to be used repeatedly, and the amount of ink used is only the amount necessary to form the pattern, and there is no risk of generating a large amount of waste. As a result, the number of steps can be reduced. Therefore, according to the intaglio offset printing method, it is possible to form a pattern with high productivity in a short time with less energy consumption, less waste of materials used, and fewer steps compared to the photolithography method. .

However, since the rubber layer of the blanket is always in contact with the ink, it is gradually swollen by the solvent contained in the ink as printing is repeated, and the wettability with respect to the ink changes accordingly. Therefore, although high-precision printing is possible as described above at the initial stage of printing, there is a possibility that high-precision and good printing cannot be performed while printing is repeated.
That is, if a solvent with low wettability that hardly swells the rubber layer is used as the solvent contained in the ink, the wettability hardly changes even when printing is repeated, so that stable printing can be performed. However, an ink containing a solvent having low wettability has a problem in that disconnection is likely to occur particularly in a fine line pattern because transferability from a plate to a rubber layer is not sufficient.

  The disconnection is a defect that should be avoided most, and to prevent it, a solvent that can swell the rubber layer to some extent must be used. When printing is repeated using an ink containing such a solvent, the rubber layer gradually becomes loose. The ink wettability gradually increases. Along with this, the ink easily spreads, and the line width of the fine line pattern is gradually widened, fine stains on the plate surface are transferred, and the transferability of the ink from the rubber layer to the substrate is improved. It gradually decreases.

Therefore, for example, it is conceivable to remove the solvent by heating the rubber layer in the middle of printing. For this purpose, it is necessary to heat to about 40 to 200 ° C. When in contact with the ink, there is a problem that the intaglio is thermally expanded and printing accuracy is lowered.
After printing by transferring the ink again to the substrate, the rubber layer is brought into contact with the surface of the rubber layer until the next ink is transferred from the intaglio by contacting the absorber with a solvent absorbing function. It has been proposed to absorb and remove the solvent that swells (see Patent Document 1).

  However, if a large amount of solvent is removed at a time, the state of the rubber layer changes abruptly, so that the ink transferability and the line width may fluctuate greatly before and after the removal. Moreover, the swelling mechanism is very complicated, and it is not simply that the solvent should be removed. It is important to determine when and how much solvent needs to be removed, but relying on the experience and intuition of the printing operator to produce a product with stable quality Automation is desired.

  While the dielectric constant of silicone rubber is about 2-3, the amount of solvent swelling the rubber layer is quantified using the fact that the dielectric constant of solvents with high polarity is about 10-60. However, it has been proposed to remove the solvent based on the result (see Patent Document 2). Specifically, the amount of solvent swelling the rubber layer is quantified by measuring the capacitance between a pair of electrodes embedded at an arbitrary position in the thickness direction of the rubber layer using an LCR meter. can do.

  However, in order to quantify the amount of solvent as accurately as possible by this method, it is important that the difference in dielectric constant between the rubber forming the rubber layer and the solvent is as large as possible, which limits the types of rubber and solvent to be combined. There is a problem of being. Also, even if a combination with a large difference in dielectric constant between rubber and solvent is selected, the amount of solvent cannot be accurately determined because the change in dielectric constant is small while the amount of solvent swelling the rubber layer is small. There is also a problem.

It is also possible to measure the spectrum of the rubber layer using an infrared spectrophotometer (such as FT-IR) and to quantify the concentration of the solvent swelling the rubber layer from the area of the solvent peak contained therein. It is done. However, in that case, the infrared absorption sensor needs to be brought into close contact with the surface of the rubber layer, and the trace of the attached sensor may affect the print quality.
JP 2006-35769 A JP 2006-175850 A

  The present invention stabilizes the amount of solvent swelling the blanket rubber layer as accurately as possible without limiting the type of rubber layer and solvent or affecting the print quality. Another object of the present invention is to provide a printing method capable of performing good printing and a printing machine suitable for carrying out the printing method.

  The present invention relates to a printing method in which ink carried on the surface of a rubber layer of a blanket is transferred to a surface of a printing medium and printed, and the Raman scattered light generated when the rubber layer is irradiated with laser light Measuring the amount of the solvent of the ink soaked into the rubber layer from the difference in frequency between the irradiation light and the scattered light, and the solvent soaked into the rubber layer based on the result of the quantification. And a removing step.

  When a substance is irradiated with laser light, the so-called Raman effect causes scattered light having the same frequency as the irradiated laser light (referred to as “Rayleigh scattered light”), and the irradiated laser light has a different frequency, and Stokes scattered light and It is known that two types of scattered light called anti-Stokes scattered light (also collectively called “Raman scattered light”) are generated. The present invention quantifies the amount of the solvent that swells the rubber layer by Raman spectroscopy using the Raman effect.

  That is, according to the principle of Raman spectroscopy, the frequency shift (Raman shift) of the Raman scattered light shows a value specific to the structure of the substance. Therefore, the Raman scattered light of the rubber layer and the solvent to be used is measured in advance. In this case, it is possible to identify an arbitrary solvent that swells an arbitrary rubber layer without limiting the types of rubber and solvent forming the rubber layer. Further, in the Raman spectrum obtained by detecting the generated Raman scattered light with a detector via an interferometer, a spectroscope, etc., the ratio between the specific peak of rubber forming the rubber layer and the specific peak of the solvent ( By determining the peak height ratio, the area ratio, etc., it is possible to quantify the solvent that swells the rubber layer from a very small range that cannot be detected by conventional methods such as dielectric constant measurement.

  In addition, by irradiating the rubber layer with laser light and measuring the scattered light as described above, the amount of solvent can be quantified without any trace in a completely non-contact state with the rubber layer. The printing quality is not affected by this operation. Therefore, according to the printing method of the present invention for printing while quantifying the amount of solvent by the Raman spectroscopy, the type of the rubber layer and the solvent is not limited, and the print quality is not affected as much as possible. It is possible to perform stable and good printing while accurately quantifying the amount of the solvent swelling the rubber layer of the blanket.

  The present invention is a printing machine that performs printing by transferring ink carried on the surface of a rubber layer of a blanket to the surface of a printing medium, and holding the blanket, and holding the blanket Measure the amount of Raman scattered light generated when the rubber layer of the blanket is irradiated with laser light, and determine the amount of ink solvent soaked into the rubber layer from the difference in frequency between the irradiated light and scattered light And a quantitative unit.

According to the present invention, the solvent amount quantification unit based on the Raman spectroscopy can be always quantified under a certain condition by incorporating the solvent amount quantification unit into the printing machine. Based on the result, the blanket rubber layer is swollen. It is possible to perform stable and good printing by automatically or manually removing the solvent.
In the printing press of the present invention, the solvent amount determination unit includes a laser light source, a light receiving unit that receives scattered light, an objective lens disposed between the light receiving unit and the rubber layer, and the objective lens and the light receiving unit. It is preferable that an objective lens and a confocal aperture are disposed between the objective lens and the aperture, and the distance between the objective lens and the aperture is adjustable.

According to the present invention, by irradiating a rubber layer with a laser beam from a laser light source, a component from a specific position in the thickness direction of Raman scattered light generated in a wide range in the thickness direction of the rubber layer is obtained. Then, it can be selectively taken out by the objective lens and the aperture and guided to the light receiving section. Therefore, the amount of the solvent at a specific position in the thickness direction of the rubber layer can be quantified.
Also, by adjusting the distance between the objective lens and the aperture and the surface of the rubber layer, the component generated at any position in the thickness direction of the rubber layer of the Raman scattered light is selected by the objective lens and the aperture. It is possible to select whether to take out the light and guide it to the light receiving unit. Therefore, for example, by repeating the quantification while gradually changing the distance between the objective lens and the aperture and the surface of the rubber layer, the distribution of the solvent amount in the thickness direction of the rubber layer can be measured, and the swelling of the rubber layer It becomes possible to grasp the situation in more detail and remove the solvent more accurately.

Further, the printing machine of the present invention includes a solvent removal mechanism that removes the solvent that has penetrated into the rubber layer, and a control unit that operates the solvent removal mechanism based on a result of determination by the solvent amount determination unit. Is preferred.
According to the present invention, for example, a plurality of operation patterns of the solvent removal mechanism are registered in the control unit, and any one of the operation patterns is selected according to the result of quantification by the solvent amount quantification unit. The solvent removal operation can be automated.

  According to the present invention, the amount of the solvent swelling the blanket rubber layer is determined as accurately as possible without restricting the types of the rubber layer and the solvent or affecting the print quality. It is possible to provide a printing method capable of stably performing good printing and a printing machine suitable for performing the printing method.

  FIG. 1 is a schematic view showing an example of an embodiment of a printing machine of the present invention for carrying out the printing method of the present invention. Referring to FIG. 1, a printing machine 1 of this example includes a blanket cylinder 3 as a holding member that holds a sheet-like blanket 2 in a cylindrical shape on its outer periphery, and an intaglio plate 4 and a substrate 5 as a substrate to be printed. An intaglio offset printing machine provided with a base plate 6 for holding. In the printing press 1, the blanket cylinder 3 is shown between a raised position separated from the base plate 6 and a lowered position where the blanket 2 is brought into contact with the surface of the intaglio 4 or the substrate 5 (not shown). , And moved up and down as indicated by solid arrows in the figure.

Further, the base plate 6 has a position between the position where the blanket 2 is brought into contact with the left end of the surface of the intaglio 4 and the position where the surface of the substrate 5 is brought into contact with the right end in the drawing. It is moved left and right as indicated by solid arrows in the figure. Then, printing is performed on the surface of the substrate 5 by combining the vertical movement and the horizontal movement.
That is, when ink is supplied to the surface of the intaglio 4 in the state of FIG. 1 (initial state), and then the base plate 6 is moved to the right, the doctor blade 7 brought into contact with the surface of the intaglio 4 is In the figure, the ink is filled in a recess (not shown) of the intaglio 4 by being relatively moved on the surface from the right end to the left end of the intaglio 4.

At the same time, when the blanket cylinder 3 is lowered and the blanket 2 is brought into contact with the right end of the surface of the intaglio 4 in the drawing, the base plate 6 is moved further to the right, and the blanket 2 is By being driven and rotated together with the blanket cylinder 3 along with the movement, the ink filled in the recesses of the intaglio 4 is transferred to the surface.
Next, the base 6 is moved leftward with the blanket cylinder 3 raised, and then lowered to bring the blanket 2 into contact with the right end of the surface of the substrate 5 in the drawing. When the base plate 6 is moved in the right direction, the blanket 2 is driven and rotated along with the blanket cylinder 3 so that the ink transferred on the surface is retransferred to the surface of the substrate 5. The

  Thereafter, when the blanket cylinder 3 is raised again and the base plate 6 is returned to the initial state shown in FIG. 1 and continuous printing is performed, the steps described above are repeated. Further, when the printed substrate 5 is removed from the base plate 6 and subjected to predetermined processing such as drying and baking, for example, an electrode on the front plate of the plasma display panel, an electromagnetic wave shield, or a color filter layer of the liquid crystal display panel is manufactured. .

The printing machine 1 of this example includes a solvent amount quantifying unit 8 for quantifying the amount of the solvent that has soaked into the rubber layer of the blanket 2 around the blanket cylinder 3 that has been returned to the initial state, and the rubber layer soaked in the rubber layer. And a solvent removal mechanism 9 for removing the contained solvent. The solvent amount determination unit 8 and the solvent removal mechanism 9 are each connected to the control unit 10.
Among these, the solvent quantity determination unit 8 includes a laser light source 11, an objective lens 12, and a light receiving unit 13. The objective lens 12 is for guiding Raman scattered light, which is generated when the laser light is irradiated from the laser light source 11 to the rubber layer of the blanket 2 to the light receiving unit 13 as indicated by the one-dot chain line arrow in the figure. It is. Although not shown, the light receiving unit 13 amplifies an interferometer, a spectroscope, a detector, and a detection value obtained by the detector for obtaining a Raman spectrum from the Raman scattered light guided by the objective lens 12. And an amplifier sent to the control unit 10.

  FIG. 2 is a schematic cross-sectional view showing a modification of the solvent amount quantification unit 8. Referring to FIG. 2, the solvent amount quantifying unit 8 of this example is provided with a confocal aperture (confocal aperture) 14 between the objective lens 12 and the light receiving unit 13. It is different from the example. According to the solvent amount quantification unit 8, for example, among the Raman scattered light generated in a wide range in the thickness direction of the rubber layer 15 of the blanket 2, as indicated by solid line, broken line, and alternate long and short dash arrows in the figure, Only the component (solid line component) from a specific position in the thickness direction can be selectively extracted by the objective lens 12 and the aperture 14 and guided to the light receiving unit 13. Therefore, the amount of the solvent at a specific position in the thickness direction of the rubber layer 15 of the blanket 2 can be quantified.

  In this example, the objective lens 12 and the aperture 14 are disposed so that the distance between the objective lens 12 and the aperture 14 and the surface of the rubber layer 15 of the blanket 2 can be adjusted, so that the Raman scattered light in the thickness direction of the rubber layer 15 can be adjusted. It is possible to select at which position the generated component is selectively extracted by the objective lens 12 and the aperture 14 and guided to the light receiving unit 13. Therefore, for example, according to the operation program registered in advance in the control unit 10, the rubber layer is obtained by repeating the quantification while gradually changing the distance between the objective lens 12 and the aperture 14 and the surface of the rubber layer 15 of the blanket 2. The distribution of the solvent amount in the thickness direction of 15 can be measured, and the swelling state of the rubber layer 15 can be grasped more finely and the solvent can be removed more accurately.

With reference to FIG. 1, the quantitative value of the amount of solvent detected by the light receiving unit 13 is input to the control unit 10. The control unit 10 determines the swelling state of the rubber layer 15 based on the input value and the basic data registered in advance, and operates the solvent removal mechanism 9 according to the operation program registered in advance based on the result. .
As described above, the determination of the amount of solvent by the solvent amount determination unit 8 is performed in a non-contact manner on the surface of the blanket 2 and does not affect the print quality. Therefore, the determination is actually performed on the blanket 2. You may carry out with respect to the area | region where the ink used as the electrode of a plasma display panel is transferred. However, if the print pattern changes, the ink transfer position will change.Therefore, regardless of the print pattern difference, considering that the amount of solvent is always stably quantified, a dummy pattern is placed in a predetermined area outside the actual print pattern. It is preferable that the amount of solvent in the region of the dummy pattern is measured.

  As the solvent removal mechanism 9, for example, a solvent absorber is brought into contact with the surface of the rubber layer of the blanket 2, and the solvent is directly absorbed and removed by the solvent absorber, or the surface is irradiated with infrared rays. Various methods such as a method of removing the solvent by evaporating it by blowing hot air or cold air, a method of removing the solvent by evaporating and removing the solvent by covering the surface with a vacuum chamber Any of them can be used.

  According to the printing press 1 of this example provided with the above-mentioned parts, the solvent amount quantification part 8 incorporated in advance restricts the type of the rubber layer 15 and the solvent of the blanket 2 under constant conditions, and affects the printing quality. The amount of the solvent that swells the rubber layer 15 is quantified as accurately as possible without causing any influence, and the solvent removal operation by the solvent removal mechanism 9 is automatically performed based on the result. It is possible to perform stable and good printing.

The configuration of the present invention is not limited to the example shown in the drawings described above, and various modifications can be made without departing from the scope of the present invention. For example, the printing method does not use the printing machine 1, but prints using a normal printing machine, and at any point in time, based on the results measured by the printing worker with a measuring instrument using Raman spectroscopy, You may make it perform the removal operation of a solvent.
The printing machine 1 is provided with a display unit that informs the printing operator that the solvent removal is necessary based on the result of the determination by the solvent amount determination unit 8. Accordingly, the solvent removal mechanism 9 may be operated manually to perform the solvent removal operation. The printing method is not limited to the intaglio offset, and for example, a reverse printing method can be adopted. FIG. 3 is a schematic view showing an example of an embodiment of a printing machine 16 for carrying out the reverse printing method.

The printing machine 16 in the illustrated example is provided with a slit die coater 17 for applying ink to the entire surface of the blanket 2 around the blanket cylinder 3 returned to the initial state. It is different from the machine 1. Since the other portions are the same as those of the printing press 1, the same portions are denoted by the same reference numerals and description thereof is omitted.
In the reversal printing method using the printing machine of FIG. 3, first, ink is applied to the entire surface of the blanket 2 using the slit die coater 17, and then the blanket cylinder 3 is lowered while moving the platform 6 to the right. Then, with the blanket 2 in contact with the right end of the surface of the intaglio 4 in the drawing, the platform 6 is moved further to the right. Then, as the blanket 2 is driven and rotated along with the movement of the blanket 2, the ink in contact with the surface of the intaglio plate 4 other than the concave portion out of the ink applied to the entire surface of the blanket 2 is It is transferred to the surface and removed from the surface of the blanket 2.

  Next, the base 6 is moved leftward with the blanket cylinder 3 raised, and then lowered to bring the blanket 2 into contact with the right end of the surface of the substrate 5 in the drawing. When the base plate 6 is moved in the right direction, the blanket 2 is driven and rotated along with the movement of the blanket cylinder 3, so that the blanket 2 is not removed corresponding to the concave portion of the intaglio plate 4 and the surface of the blanket 2 is removed. The remaining ink is transferred to the surface of the substrate 5.

  Thereafter, when the blanket cylinder 3 is raised again and the base plate 6 is returned to the initial state shown in FIG. 1 and continuous printing is performed, the steps described above are repeated. Further, when the printed substrate 5 is removed from the base plate 6 and subjected to predetermined processing such as drying and baking, for example, an electrode on the front plate of the plasma display panel, an electromagnetic wave shield, or a color filter layer of the liquid crystal display panel is manufactured. .

  In the printing machine 16 that employs the reverse printing method in the example shown in the figure, the solvent amount quantification unit 8 incorporated in advance restricts the type of the rubber layer 15 and the solvent of the blanket 2 and the printing quality under constant conditions at all times. The amount of the solvent that swells the rubber layer 15 is quantified as accurately as possible without influencing, and the solvent removal operation by the solvent removal mechanism 9 is automatically performed based on the result. This makes it possible to perform stable and good printing.

<Confirmation test 1>
As a sample, diethylene glycol monobutyl ether acetate (butyl carbylate), which is actually used for the same silicone rubber used for forming the rubber layer of the blanket 2 and the ink for forming the electrode of the plasma display panel and the electromagnetic wave shield. Raman spectra of three solvents: tall acetate, abbreviated as “BCA”, terpineol, and polyethylene glycol dimethyl ether (abbreviated as “MPM”) were measured using a Raman spectrophotometer. The results are shown in FIG. The horizontal axis in FIG. 4 is the Raman shift (cm ⁻ ), and the vertical axis is the relative intensity. In the figure, in order to facilitate the comparison of the Raman spectra of the respective substances, the respective spectrum curves are shown shifted in the vertical axis direction.

FIG. 4 shows that each substance can be identified because the Raman spectrum is different for each substance. In the combination of the silicone rubber and the BCA, by detecting the ratio of the peak around 1400 cm ^-1 for silicone rubber, the peak around 1750 cm ^-1 for BCA (peaks marked ● in FIGS 4), It was confirmed from the results of FIG. 4 and other studies that the concentration of BCA as a solvent swelling the rubber layer can be quantified.

<Confirmation test 2>
BCA was brought into contact with the surface of an actual blanket provided with a rubber layer made of silicone rubber for 5 minutes to swell the rubber layer with BCA, and then the excess BCA was removed to prepare a sample.
Into the Raman spectrophotometer, an objective lens (magnification × 100) and an aperture (hole diameter 25 μm) confocal with the objective lens are incorporated, and the distance between the surface of the sample and the objective lens and the aperture is stepwise. The Raman spectrum was measured while changing. The distance is a component of the Raman scattered light generated at a depth of 300 μm, 200 μm, 100 μm, 50 μm, 10 μm, and 0 μm (that is, the surface of the rubber layer) from the surface of the rubber layer. The sample was selectively taken out by the aperture and adjusted so that it could be guided to the light receiving part of the Raman spectrophotometer. A result is shown in FIG. 5 with the result (non-swelling) of the Raman spectrum measured in the state which is not swollen with BCA for the comparison. The horizontal axis in FIG. 5 is the Raman shift (cm ⁻ ), and the vertical axis is the relative intensity. In the figure, in order to facilitate the comparison of the Raman spectra, the respective spectrum curves are shown shifted in the vertical axis direction.

FIG. 5 confirms that the solvent amount distribution in the thickness direction of the rubber layer can be measured by changing the distance between the objective lens and the aperture and the surface of the rubber layer as a sample. It was.
<Example 1>
Prepare the following components to manufacture the front plate of the plasma display panel by forming electrodes on the surface of a 42 inch diagonal glass substrate by printing with the intaglio offset printing method and baking after printing. did.

(ink)
Acrylic resin, silver powder, glass frit, and BCA as a solvent were mixed using three rolls to prepare a conductive ink to be the basis of the electrode.
(blanket)
As the blanket, an addition-type room temperature curable silicone rubber was applied on a support film and cured, and the rubber layer made of the silicone rubber had a thickness of 300 μm, a JIS A rubber hardness of 40, and a ten-point average. A silicone blanket having a roughness RZ _JIS94 of 0.1 μm and a width of 1000 mm was prepared.

(intaglio)
As the intaglio plate, a soda lime glass having a stripe pattern corresponding to the electrode having a line width of 80 μm and a pitch of 360 μm on one side and a dummy pattern for detecting the amount of solvent around the stripe pattern was prepared. As the dummy pattern, a stripe pattern having the same line width of 80 μm and a pitch of 360 μm as the stripe pattern was arranged in a square area of 10 mm × 10 mm.

(Real machine test)
The intaglio 4 and the glass substrate 5 having a diagonal size of 42 inches are set on the base plate 6 of the intaglio offset printing press 1 shown in FIG. 1, and the silicone blanket 2 is wound around the blanket cylinder 3; The ink was filled in an ink supply device (not shown). As the solvent amount quantifying unit 8, as described above, a unit including the laser light source 11, the objective lens 12, the aperture 14, and the light receiving unit 13 was prepared.

  The solvent removal mechanism 9 is a silicone blanket in which a rubber layer made of an ethylene-propylene-diene copolymer rubber (EPDM) containing no additive such as a plasticizer or an antioxidant is formed on the surface. An endless belt-like solvent absorber having a width of 1000 mm, which is the same as the width, is formed by spanning between three rollers, and the solvent absorber is placed between two of the three rollers during a printing interval. In the state of being in pressure contact with the surface of the silicone blanket, a system for removing the solvent by rotating the solvent absorber a predetermined number of times in synchronization with the rotation of the silicone blanket was prepared.

  The rotational speeds of the silicone blanket and the solvent absorber were variable speed so that they could be changed based on the measurement result of the amount of BCA (solvent amount) by the solvent amount quantifying unit 8 during the solvent removal operation. Specifically, when the amount of the BCA is large and the solvent absorption is insufficient, the rotation speed is slowed down, the contact time is lengthened, and more BCA can be removed by one removal operation. Conversely, when the amount of BCA is small and solvent absorption is sufficient, the rotational speed is increased, the contact time is shortened, and the amount of BCA that can be removed by one removal operation is suppressed.

Then, in the rubber layer of the silicone blanket, the amount of BCA at the position where the depth from the surface of the region corresponding to the dummy pattern is 50 μm is quantified every time printing is finished, and then explained. The operation of continuously printing the stripe pattern that becomes the basis of the electrode on the surface of the glass substrate 5 was repeated 10,000 times by the procedure described above.
At this time, based on the result of the transition of the BCA amount when the continuous printing is performed without the solvent removal operation by the solvent removal mechanism 9 in advance, the conditions for solvent removal by the solvent removal mechanism 9, i. The relationship between the amount of BCA described in 1) and the rotational speed of the silicone blanket and the solvent absorber was set.

  Then, based on the amount of BCA measured by the solvent amount quantification unit 8 every time printing is completed as described above and the setting, the rotational speed of the silicone blanket and the solvent absorber is 1 to 100 mm / second. In the state set to an arbitrary value within the range, during the interval until the next printing, the solvent absorber was pressed against the surface of the silicone blanket to remove the solvent.

  As a result, the amount of BCA is 2 to 3 parts by mass per 100 parts by mass of the rubber layer in the initial stage of printing, and is about 3 to 5 parts by mass per 100 parts by mass of the rubber layer during continuous printing of 10,000 times. It remained at a low level. Also, the printing results were good, and the 10,000 front plates manufactured by printing after printing were all stable in electrode line width, thickness, and resistance value. Furthermore, the printing accuracy is very good, and it is possible to ensure printing accuracy within a dimensional difference of ± 10 μm within the 42-inch plane on the 10,000 front plates. This accuracy is required for mounting on a plasma display panel. It was a level that did not cause any problems.

<Comparative example 1>
As a blanket, a silicone blanket having a width of 1000 mm and having a rubber layer thickness of 300 μm, a JIS A rubber hardness of 40, a ten-point average roughness RZ _JIS94 of 0.1 μm is prepared. did. Since the rubber layer is insulative with a volume resistivity of 10 ¹⁴ Ωcm, it was intended to quantify the degree of swelling and thus the amount of solvent from the change in conductivity due to swelling of the rubber layer.

  However, when the blanket is incorporated in the offset printing machine of FIG. 1 and printing is performed continuously while measuring the conductivity of the printed layer, a change in conductivity is detected only by a small amount of solvent swelling. could not. Therefore, as before, while the printing operator checked the printed matter, printing was performed while removing the solvent by manually operating the solvent removal mechanism 9 at a rate of once every 10 times. Variations and irregularities in printing shape occurred frequently, the defect rate was high, and stable printing could not be performed.

<Comparative example 2>
In order to form a color filter layer of three colors of RGB on the surface of a glass substrate having a diagonal size of 32 inches by printing by a reverse printing method and baking after printing, to manufacture a color filter of a liquid crystal display panel, The following members were prepared.
(ink)
Polyester-melamine resin, RGB organic pigment of any one of the three colors, dispersant, and propylene glycol monomethyl ether acetate (abbreviated as “PGMEA”) as a solvent are mixed using three rolls. Thus, an ink as a base of the color filter layer was prepared.

(blanket)
As the blanket, the same conductive silicone blanket as that prepared in Example 1 was prepared.
(intaglio)
As the intaglio, a stripe pattern corresponding to one color of the color filter layer having a line width of 100 μm and a pitch of 300 μm was formed on one side of soda lime glass, and a dummy pattern for detecting the amount of solvent was formed around the stripe pattern. The thing for three colors of RGB was prepared. As the dummy pattern, a stripe pattern having the same line width of 100 μm and a pitch of 300 μm as the stripe pattern was arranged in a square area of 10 mm × 10 mm.

(Slit die coater)
A slit die coater having a slit interval of 50 μm was prepared.
(Real machine test)
The intaglio 4 and the glass substrate 5 having a diagonal size of 32 inches are set on the base plate 6 of the reverse printing machine 16 shown in FIG. 3, and the silicone blanket 2 is wound around the blanket cylinder 3 and further slitted. The die coater 17 was filled with the ink. As the solvent amount quantifying unit 8, as described above, a unit including the laser light source 11, the objective lens 12, the aperture 14, and the light receiving unit 13 was prepared.

As the solvent removal mechanism 9,
(1) A suction nozzle having a width of 1000 mm which is the same as the width of the silicone blanket and having a slit interval of 100 μm is opposed to the surface of the blanket 2 wound around the blanket cylinder 3 at a distance of 100 μm, and the blanket 2 A method of vacuum suction so that the degree of vacuum on the surface is 13.3322 hPa;
(2) A spray nozzle having a width of 1000 mm which is the same as the width of the silicone blanket is opposed to the surface of the blanket 2 wound around the blanket cylinder 3 at a distance of 10 mm, and is sufficiently dried from the spray nozzle. Blow spray type that blows nitrogen gas treated cleanly through a membrane filter etc.,
Prepared.

  Using the vacuum suction type and blow blowing type solvent removal mechanism 9, a solvent removal operation is performed on the silicone blanket during a printing interval, and the rotational speed of the silicone blanket is changed during the solvent removal operation. A variable speed method was adopted so that the amount of PGMEA (solvent amount) measured by the solvent amount determination unit 8 could be changed. Specifically, when the amount of the PGMEA is large and the solvent absorption is insufficient, the rotational speed is slowed down and the removal operation time is lengthened so that more PGMEA can be removed by one removal operation. On the contrary, when the amount of PGMEA is small and the solvent absorption is sufficient, the rotational speed is increased, the time for the removal operation is shortened, and the amount of PGMEA that can be removed by one removal operation is suppressed. .

  Then, the amount of PGMEA at the position where the depth from the surface of the rubber layer of the silicone blanket corresponding to the dummy pattern is 50 μm is quantified every time one printing is finished, and then explained. The operation of continuously printing a stripe pattern for one color of the color filter layer on the surface of the glass substrate 5 was repeated 10,000 times by the procedure described above.

At this time, based on the result of transition of the amount of PGMEA when the continuous printing is performed without the solvent removal operation by the solvent removal mechanism 9 in advance, the conditions for the solvent removal by the solvent removal mechanism 9, i. The relationship between the amount of PGMEA described above and the rotational speed of the silicone blanket was set.
Based on the amount of PGMEA measured by the solvent amount quantification unit 8 every time printing is completed as described above and the setting, the rotational speed of the silicone blanket is arbitrarily set within the range of 1 to 100 mm / second. In the state set to this value, during the interval until the next printing, an operation was performed to remove the solvent by vacuum suction with a suction nozzle while blowing nitrogen gas from the spray nozzle.

  As a result, the amount of PGMEA is about 5 parts by mass per 100 parts by mass of the rubber layer in the initial stage of printing, and the maximum value per 100 parts by mass of the rubber layer is about 15 parts by mass even during continuous printing of 10,000 times. Remained at a low level. Also, the printing result was good, and the 10,000 color filters manufactured by repeatedly printing after printing three colors of RGB in the same procedure were stable in both line width and thickness.

It is the schematic which shows an example of embodiment of the printing machine of this invention for enforcing the printing method of this invention. It is a schematic sectional drawing which shows the modification of a solvent amount fixed_quantity | quantitative_assay part. It is the schematic which shows the other example of embodiment of the printing machine of this invention for enforcing the printing method of this invention. In confirmation test 1, it is a graph which shows the result of having measured the Raman spectrum of silicone rubber and three types of solvents using the Raman spectrophotometer, respectively. In confirmation test 2, it is a graph which shows the result of having measured the Raman spectrum, changing the distance between an objective lens and an aperture, and the surface of a rubber layer.

Explanation of symbols

1, 16 Printing machine 2 Blanket 3 Blanket cylinder (holding member)
5 Substrate (substrate)
8 Solvent Amount Determination Unit 9 Solvent Removal Mechanism 10 Control Unit 11 Laser Light Source 12 Objective Lens 13 Light Receiving Unit 14 Aperture 15 Rubber Layer

Claims (4)

  A printing method in which the ink carried on the surface of the rubber layer of the blanket is transferred to the surface of the substrate to be printed, and the Raman scattered light generated when the rubber layer is irradiated with laser light is measured, A step of quantifying the amount of the solvent of the ink soaked into the rubber layer from the difference in frequency between the irradiation light and the scattered light, and a step of removing the solvent soaked into the rubber layer based on the result of the quantification; A printing method comprising:   A printing machine for printing by transferring ink carried on the surface of a rubber layer of a blanket to the surface of a printing medium, the holding member holding the blanket, and the blanket rubber layer held by the holding member A solvent amount quantification unit for measuring the amount of Raman scattered light generated when the laser beam is irradiated and determining the amount of the solvent of the ink soaked into the rubber layer from the difference in frequency between the irradiation light and the scattered light. A printing machine comprising:   The solvent amount quantification unit is disposed between the laser light source, the light receiving unit that receives scattered light, the objective lens disposed between the light receiving unit and the rubber layer, and the objective lens and the light receiving unit. The printing machine according to claim 2, further comprising an objective lens and a confocal aperture, wherein the distance between the objective lens and the aperture is adjustable with respect to the surface of the rubber layer.   The printing machine according to claim 2 or 3, further comprising: a solvent removal mechanism that removes the solvent that has soaked into the rubber layer; and a control unit that operates the solvent removal mechanism based on a result of determination by the solvent amount determination unit.

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