JP2017039306A - Printing device and printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing device and printing method which have high printing accuracy.SOLUTION: A printing device is configured to discharge an ink in a predetermined pattern shape to a plate surface of a printing plate and then transfer the discharged ink in a predetermined pattern shape to a substrate. A mark as a reference of an ink droplet landing position is formed on the plate surface of the printing plate. The printing device includes: a rotatable plate cylinder which is provided with a printing plate; an image recording unit which discharges ink in a predetermined pattern shape to the plate surface of the printing plate from a plurality of nozzles in an ink jet method; a reading unit which acquires the position of the mark, position information of a plurality of droplet landing positions of ink discharged from the image recording unit to the mark, and obtains data on the difference between the position of the mark and the droplet landing positions of ink; and an adjustment unit which adjusts the discharge timing of the ink in the image recording unit on the basis of the data on the difference between the position of the mark and the droplet landing position of ink obtained by the reading unit.SELECTED DRAWING: Figure 1

Description

  The present invention acquires position information of a plurality of ink landing positions ejected with respect to a mark serving as a reference for the ink landing position, and controls the ink ejection timing to accurately insert the ink into the printing plate. More particularly, the present invention relates to a printing apparatus and a printing method that can be used for manufacturing a gate electrode, a source electrode, a drain electrode, a wiring, and the like of a thin film transistor used for electronic paper.

  In recent years, a fine pattern such as a gate electrode, a source electrode, a drain electrode, a metal wiring, and an electric wiring pattern of a thin film transistor is formed on a glass substrate, a resin substrate, or the like by using a printing method. A substrate on which a fine pattern is formed by a liquid containing conductive particles such as metal by a printing method is used for thin display devices such as electronic paper and a liquid crystal display, portable communication devices, and the like.

  There is an inking technology that improves the soiling and plate durability associated with doctoring by eliminating the need for doctoring by making the required amount of inking in intaglio printing necessary by using an inkjet method. . As a specific example of the inking technique, for example, there is a pattern printing apparatus of Patent Document 1. In the pattern printing apparatus of Patent Document 1, a thin resin layer is provided on a flexible metal plate-like intaglio, and an ink-repellent pattern is provided thereon to form a recess. Ink is ejected from below into the recess by ink jet of the ink supply means. After supplying the ink, the ink is dried so as not to lose the viscosity by ejecting the solvent from the ink in the recess by the ink drying means. The printing medium and the flexible metal flat plate-shaped intaglio are positioned and the flexible metal flat plate-shaped intaglio is pressed using the press / peeling cylinder of the ink transfer means to roll the ink in the recess. Is transferred to the substrate. After the ink transfer, the flexible metal flat plate-shaped intaglio is peeled off while being bent.

  The fine patterns used in the above-described thin display devices such as electronic paper and liquid crystal display, and portable communication devices are currently required to have high definition and high positional accuracy. Patent Document 2 describes a discharge timing generation method that can be corrected in consideration of actual expansion of a substrate. In Patent Document 2, at least two alignment marks are provided on a substrate so as to be arranged with a predetermined design interval between each other, and an interval between the two alignment marks is measured using an encoder, and the measurement result is pulsed. The design interval is divided by the number of pulses, the result of division is used as an actual encoder value, and the timing at which droplets are ejected onto the substrate is controlled using the actual encoder value.

JP 2005-81726 A JP 2005-246123 A

As described above, Patent Document 1 describes that a flexible metal flat plate-shaped intaglio is pressed and ink in the recess is transferred to a printing medium. For example, when the plate mounting accuracy is low, The ink pattern is not modified according to the plate attachment. If an error occurs during pattern formation, there is a problem that printing accuracy is lowered.
In Patent Document 2, an interval between two alignment marks arranged at a predetermined design interval is measured using an encoder, the measurement result is defined as the number of pulses, the design interval is divided by the number of pulses, and the division result is obtained. The encoder value is used, and the actual encoder value is used to control the timing of ejecting droplets onto the substrate.
However, it takes 0.2 ms, for example, at a discharge speed of 5 m / s and a distance of 1 mm between the nozzle and the substrate from when the discharge signal is input until the droplets are deposited on the substrate. For this reason, the position of the encoder, the discharge timing, and the landing position do not match. Therefore, slight fluctuations in the feed will cause a shift in the landing position. In particular, in the state where the substrate is not flat but wound around the drum, even if the encoder does not fluctuate, the feed amount changes due to eccentricity or unevenness in the film thickness of the substrate. Ink cannot be ejected.

  An object of the present invention is to provide a printing apparatus and a printing method that solve the above-described problems based on the prior art and have high printing accuracy.

  In order to achieve the above-described object, the present invention is a printing apparatus that, after ejecting ink in a predetermined pattern on a printing plate surface, transfers the ink ejected in a pattern to a substrate, A mark serving as a reference for the ink landing position is formed on the plate surface of the printing plate, the printing plate is provided, and ink is applied to the plate surface of the printing plate by a rotatable plate cylinder and a plurality of nozzles by an inkjet method. With respect to the image recording unit that discharges in a predetermined pattern, the position of the mark, and the position information of a plurality of ink landing positions discharged from the image recording unit with respect to the mark, the position of the mark and the ink A reading unit that obtains data on the difference in droplet landing position, and an adjustment unit that adjusts the ink ejection timing in the image recording unit based on data on the difference between the mark position and the ink landing position obtained by the reading unit. With features There is provided a that printing device.

The marks are preferably provided at least at three positions along a direction parallel to the rotation axis of the plate cylinder.
The mark is formed in a mark formation region, the mark is formed of a convex portion, the mark formation region is formed of a concave portion, the convex portion is an ink repellent portion, and the concave portion is preferably a parent ink portion.
The image recording unit preferably deposits ink on the mark.
Further, for example, the difference data between the mark position and the ink landing position is the difference data between the average position of the plurality of ink landing positions and the mark position.

  The present invention is a printing method in which ink is ejected in a predetermined pattern onto a plate surface of a printing plate provided on a plate cylinder, and then the ink ejected in a pattern is transferred to a substrate. A mark serving as a reference for the ink landing position is formed on the plate surface, and the position information of the plurality of ink landing positions of the ink ejected with respect to the mark position is acquired, and the mark in the rotation direction of the plate cylinder Obtaining the difference data between the position of the ink and the ink landing position, adjusting step for adjusting the ink ejection timing in the image recording unit based on the difference data between the mark position and the ink landing position, and adjustment And a discharge step of discharging ink onto a printing plate surface at a discharge timing adjusted in the step.

The marks are preferably provided at least at three positions along a direction parallel to the rotation axis of the plate cylinder.
The mark is formed in a mark formation region, the mark is formed of a convex portion, the mark formation region is formed of a concave portion, the convex portion is an ink repellent portion, and the concave portion is preferably a parent ink portion.
Ink is preferably deposited on the mark. Further, for example, the difference data between the mark position and the ink landing position is the difference data between the average position of the plurality of ink landing positions and the mark position.

  According to the present invention, it is possible to provide a printing apparatus and a printing method apparatus configuration with high printing accuracy.

It is a schematic diagram which shows the printing apparatus of embodiment of this invention. FIG. 3 is a schematic diagram illustrating an image recording unit of the printing apparatus according to the embodiment of the present invention. (A) is a top view which shows arrangement | positioning of the nozzle of an inkjet head, (b) is a top view which shows the other example of arrangement | positioning of the nozzle of an inkjet head. It is a schematic diagram which shows the ink supply mechanism of the printing apparatus of embodiment of this invention. (A) is a schematic diagram which shows an example of the printing plate used for the printing apparatus of embodiment of this invention, (b) is a schematic diagram which shows an example of the printing plate used for the printing apparatus of embodiment of this invention. FIG. It is a schematic diagram which shows an example of the maintenance part of the printing apparatus of embodiment of this invention. It is a schematic diagram which shows the discharge observation part and nozzle observation part of the maintenance part of the printing apparatus of embodiment of this invention. It is a schematic diagram which shows an example of the thin-film transistor formed with the printing apparatus of embodiment of this invention. It is a schematic diagram which shows the 1st example of the mark used as the reference | standard of the landing position of the ink formed in the printing plate. It is a schematic diagram which shows the 2nd example of the mark used as the reference | standard of the ink landing position formed in the printing plate. It is a schematic diagram which shows the 3rd example of the mark used as the reference | standard of the ink landing position formed in the printing plate. It is a schematic diagram which shows the 4th example of the mark used as the reference | standard of the landing position of the ink formed in the printing plate. It is a schematic diagram which shows the 5th example of the mark used as the reference | standard of the landing position of the ink formed in the printing plate. It is a schematic diagram which shows the 6th example of the mark used as the reference | standard of the landing position of the ink formed in the printing plate. It is a schematic diagram which shows an example of inclination correction of the printing apparatus of embodiment of this invention. (A) is a schematic diagram which shows an example of the specific example of inclination correction of the printing apparatus of embodiment of this invention, (b) is another example of the specific example of inclination correction of the printing apparatus of embodiment of this invention. It is a schematic diagram which shows an example. (A)-(c) is typical sectional drawing which shows the formation process of the wiring pattern formed with the printing apparatus of embodiment of this invention in order of a process. (A) is typical sectional drawing which shows the 1st example of the printing plate before transfer, (b) is typical sectional drawing which shows the pattern after transfer to a printing plate. (A) is typical sectional drawing which shows the 2nd example of the printing plate before transfer, (b) is typical sectional drawing which shows the pattern after transfer to a printing plate. (A) is typical sectional drawing which shows the 3rd example of the printing plate before transcription | transfer, (b) is typical sectional drawing which shows an example of the pattern after transcription | transfer to a printing plate, (c) These are typical sectional views showing other examples of the pattern after transfer to a printing plate. It is a schematic diagram for demonstrating the printing method of embodiment of this invention. 3 is a flowchart illustrating a printing method according to an embodiment of the present invention.

Hereinafter, a printing apparatus and a printing method of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings. The present invention is not limited to the embodiments of the printing apparatus and printing method described below.
In the following, “to” indicating a numerical range includes numerical values written on both sides. For example, ε is a numerical value β1 to a numerical value β2, and the range of ε is a range including a numerical value β1 and a numerical value β2, and expressed in mathematical symbols, β1 ≦ ε ≦ β2.
Unless otherwise specified, angles such as “parallel”, “vertical” and “orthogonal” mean that the difference from the exact angle is within a range of less than 5 °. The difference from the exact angle is preferably less than 4 °, more preferably less than 3 °.
In addition, “same” includes an error range generally allowed in the technical field.

FIG. 1 is a schematic diagram illustrating a printing apparatus according to an embodiment of the present invention.
As illustrated in FIG. 1, the printing apparatus 10 includes a printing apparatus main body 12, a storage unit 14, an adjustment unit 16, and a control unit 18.
The printing apparatus main body 12 forms a predetermined pattern on the substrate 31 by a printing method. The printing apparatus main body 12 will be described in detail later.

The storage unit 14 stores various information used in the printing apparatus 10. The storage unit 14 stores pattern data of a pattern to be printed. This pattern data is appropriately input from the outside.
Further, as will be described in detail later, the storage unit 14 corrects the ejection pattern data and ejection timing data of the ink ejected from the inkjet head 40 and the ejection pattern data of the ink according to the mounting state of the printing plate 25. The corrected ejection timing data obtained by correcting the pattern data and the ejection timing data according to the mounting state of the printing plate 25 is also stored.

The ink ejection pattern data is data indicating an ejection pattern when ink is applied to the pattern area of the printing plate 25 using the inkjet head 40.
The ejection timing data is data indicating when ink is ejected to the pattern area of the printing plate 25 when ink is applied to the pattern area of the printing plate 25 using the inkjet head 40.

The storage unit 14 stores information on a reference shape serving as a reference for the plate surface 25a of the printing plate 25 on which ink is applied to a specific pattern.
The reference shape information is, for example, image data indicating an ideal state when ink is applied to the pattern area of the printing plate 25. In addition, when ink is applied to the pattern area of the printing plate 25 a plurality of times, the image data indicates an ideal state every time. For example, when ink is ejected to the pattern area by the ink jet method, dots are formed and ink is applied to the pattern area, an image showing an ideal arrangement of dots formed by each time of ink ejection The data is referred to as the reference shape information.

As will be described in detail later, the storage unit 14 stores information such as the arrangement positions of the marks 90 a to 90 e formed on the printing plate 25.
Further, the image data indicating the ideal state of the plate surface 25a of the printing plate 25 after the transfer is also included in the reference shape information.
The method of inputting the reference shape information and pattern data to the storage unit 14 is not particularly limited, and various interfaces are provided in the storage unit 14 and input via a storage medium and a wired or wireless network. can do.

The adjustment unit 16 performs various adjustments such as ink ejection timing and image data correction in order to ink the printing plate 25 with high accuracy.
The adjustment unit 16 includes a measurement unit 16a, an adjustment unit 16b, a correction unit 16c, and a determination unit 16d.
The measuring unit 16a detects the amount of rotation of the plate cylinder 24, and a pulse signal corresponding to the amount of rotation of the plate cylinder 24 output from a measuring device 37 (see FIG. 2) provided in the plate cylinder 24 is input. Then, by counting the number of pulses of the pulse signal corresponding to the rotation amount, the rotation amount of the plate cylinder 24, the movement amount of the inkjet head 40, the position information on the printing plate 25, and the like are obtained. The pulse signal input to the measurement unit 16a is also referred to as an encoder signal.
The adjusting unit 16b adjusts the ink ejection timing of the ink jet head 40 of the image recording unit 22 based on the difference data between the position of the mark 90 and the dot 92, which will be described in detail later, obtained by the reading unit 47. is there. In the adjustment unit 16b, corrected ejection timing data for the ejection timing of ink in the inkjet head 40 is created. The corrected ejection timing data is stored in the storage unit 14.

Further, the adjustment unit 16b discharges ink to be discharged onto the plate surface 25a based on information on the attachment of the printing plate 25 to the plate cylinder 24 obtained by the alignment camera 42, which will be described in detail later, or information on the ink landing position. Correction pattern data is corrected to correct correction pattern data or discharge timing data to generate corrected discharge timing data.
The correction ejection timing data is generated by the adjustment unit 16b at a predetermined time, for example, once a day, when the printing plate 25 is replaced or when the printing plate 25 is not replaced. The
For example, when the printing apparatus 10 is operated, the determination unit 16d compares the inclination angle α of the printing plate 25 with the allowable range based on the mounting information of the printing plate 25, and is determined to be out of the allowable range. The

When the printing plate 25 is disposed at an angle α with respect to the ideally arranged printing plate 25i based on the mounting information of the printing plate 25 obtained by the alignment camera 42, the correction unit 16c performs ink ejection pattern data. Is multiplied by cos α to create correction pattern data. The correction pattern data is stored in the storage unit 14.
For example, the correction pattern data is created by the correction unit 16c when the determination unit 16d compares the inclination angle α of the printing plate 25 with the allowable range based on the attachment information of the printing plate 25 and determines that the correction plate 16 is out of the allowable range. The
Further, the correction unit 16 c calculates a rotation amount for rotating the inkjet head 40 based on the attachment position information of the printing plate 25 obtained by the plate surface observation unit 26 and stores the rotation amount in the storage unit 14. The control unit 18 rotates the inkjet head 40 based on the rotation amount to discharge ink.

The determination unit 16d is used to acquire attachment information of the printing plate 25 provided in the plate cylinder 24. The determination unit 16d specifies the positions of the alignment marks A to D using the alignment mark position information obtained by the alignment camera 42 described later. Thereby, attachment information of the printing plate 25 provided on the plate cylinder 24 can be acquired.
The determination unit 16d compares the inclination angle α of the printing plate 25 with the allowable range based on the attachment position information of the printing plate 25 and determines whether the printing plate 25 is within the allowable range. Determination information corresponding to the determination result is output to the control unit 18. The inclination angle α of the printing plate 25 will be described later.
The determination unit 16d includes information on the plate surface 25a of the printing plate 25 on which ink is applied to a specific pattern obtained by the plate surface observation unit 26 of the printing apparatus main body 12 to be described later, and the specification stored in the storage unit 14. The reference shape information serving as a reference of the plate surface 25a of the printing plate 25 to which ink is applied is compared with the pattern, and it is determined whether the pattern is within a predetermined range with respect to the reference shape. Determination information corresponding to the determination result is output to the control unit 18.

  Moreover, in the determination part 16d, when it remove | deviates from the predetermined range, the location etc. which remove | deviated are also specified. For example, when ink is applied to the pattern area, the portion where the ink has protruded is specified. Further, in the case where ink is applied to the pattern area by the ink jet method, the determination unit 16d can specify a shift in the position of dots formed by the ink, an area where dots are missing, and the like. As a result, as described later, the ink discharge amount and the like are adjusted according to the location specified by the control unit 18.

The control unit 18 is connected to the printing apparatus main body 12, the storage unit 14, and the adjustment unit 16, and controls each element of the printing apparatus main body 12, the storage unit 14, and the adjustment unit 16.
Further, the control unit 18 controls each unit according to each result obtained by the adjustment unit 16. For example, when correction pattern data of ejection pattern data is created by the adjustment unit 16 by the control unit 18, ink is ejected from the inkjet head 40 based on the correction pattern data.
In the adjustment unit 16b, corrected ejection timing data for the ejection timing of ink in the inkjet head 40 is created.

Next, the printing apparatus main body 12 will be described.
Since the printing apparatus main body 12 has a clean atmosphere for printing, each part is provided in the inside 20 a of the casing 20. A filter (not shown) and air conditioning equipment (not shown) are provided so that the inside 20a of the casing 20 has a predetermined cleanliness.
The printing apparatus main body 12 includes an image recording unit 22, a plate cylinder 24, a plate surface observation unit 26, a stage 30, a drying unit 32, an ionizer 33, a cleaning unit 34, and a maintenance unit 36.
An image recording unit 22, a plate surface observation unit 26, a drying unit 32, an ionizer 33 and a cleaning unit 34 are provided so as to surround the surface 24 a of the plate cylinder 24. The cleaning unit 34 is provided in contact with the surface 24 a of the plate cylinder 24.

The substrate 31 is disposed on the stage 30. When the plate cylinder 24 rotates in a state where the stage 30 is disposed at the printing position Pp below the plate cylinder 24, the printing plate 25 and the surface 31a of the substrate 31 come into contact with each other. Is arranged. As a result, the ink applied in a predetermined pattern on the plate surface 25 a of the printing plate 25 is transferred to the surface 31 a of the substrate 31.
In addition, in the printed board | substrate 31, according to the characteristic of an ink, an ink is baked with a heat | fever, light, etc., for example. Any publicly known one used for baking ink using heat and light can be used as appropriate. The firing of the ink on the substrate 31 may be performed inside the casing 20a or outside.

  In the printing apparatus 10, ink is applied to the pattern area of the printing plate 25 provided on the plate cylinder 24, but the ink application may be completed once or the ink may be applied multiple times. When the ink is applied a plurality of times, the plate cylinder 24 is rotated by the number of times the ink is applied. For example, when the ink is applied in four times, the plate cylinder 24 is rotated four times. Giving ink is called inking. Moreover, it is said that it scans to perform ink once among several times.

Hereinafter, each part of the printing apparatus main body 12 will be described.
The image recording unit 22 applies ink to the plate surface 25a of the printing plate 25, and the image recording unit 22 applies ink in a predetermined pattern to the plate surface 25a. The image recording method of the image recording unit 22 is not particularly limited, and for example, an ink jet method is used.

The plate cylinder 24 is rotatable in one direction, for example, the Y direction, around the rotation shaft 24b. The Y direction is the rotational direction. The Y direction is also called the feed direction. The plate cylinder 24 is rotated while holding the printing plate 25 to transfer the ink on the plate surface 25a of the printing plate 25 applied in a predetermined pattern onto the surface 31a of the substrate 31. is there.
For example, a motor (not shown) for rotating the plate cylinder 24 is provided on the rotating shaft 24b via a gear (not shown) or the like. Also, a direct drive motor without a gear can be provided. The motor is controlled by the control unit 18. The rotating shaft 24b is provided with a measuring device 37 for detecting the rotation and the rotation amount. The measuring device 37 is connected to the measuring unit 16a and is constituted by, for example, a rotary encoder. A pulse signal obtained by a rotary encoder according to the amount of rotation of the plate cylinder 24 is input to the measurement unit 16a. By counting the number of pulses of the pulse signal obtained by the rotary encoder with the measuring unit 16a, the amount of rotation of the plate cylinder 24, the amount of movement of the inkjet head 40, position information on the printing plate 25, and the like can be obtained. Thereby, the rotation amount of the plate cylinder 24, the movement amount of the inkjet head 40, the position information on the printing plate 25, and the like can be expressed by the number of pulses of the measurement unit 16a.

The substrate 31 to be transferred is not particularly limited, but film substrates such as PEN (polyethylene naphthalate), PET (polyethylene terephthalate), and PC (polycarbonate), glass epoxy substrates, ceramic substrates, and glass substrates are used. be able to. As a transfer method, a rigid substrate such as a glass substrate can be transferred by fixing the substrate 31 on the stage 30 and bringing it into close contact with the plate cylinder 24 as described above.
When a film is used for the printing plate 25, an impression cylinder may be used so that the film is fixed to the impression cylinder and brought into close contact with the plate cylinder 24 for transfer.

The plate surface observation unit 26 is disposed downstream of the image recording unit 22 in the Y direction of the plate cylinder 24. The plate surface observation unit 26 acquires information on the plate surface 25a of the printing plate 25 to which ink has been applied. The plate surface observation unit 26 also acquires information on the plate surface 25 a of the printing plate 25 after the ink is transferred to the substrate 31.
The configuration of the plate surface observation unit 26 is not particularly limited as long as it can acquire information on the plate surface 25a of the printing plate 25 before and after ink transfer. Since the printing plate 25 is often rectangular, it is preferable to use a line sensor and line illumination. In this case, plate surface imaging data is obtained as information on the plate surface 25a. The plate surface imaging data is determined by being compared with the reference shape information by the determination unit 16d of the adjustment unit 16 as described above.

As the line sensor, for example, a monochrome CMOS (complementary metal oxide semiconductor) sensor or a CCD (charge coupled device) sensor can be used. Note that the line sensor may not be a color sensor in order to observe the shadow of the ejected ink droplet. Further, a lens and various filters may be provided in front of the line sensor. As the line-shaped illumination, for example, LEDs (light emitting diodes) arranged in a straight line can be used.
The printing plate observation unit 26 is connected to the control unit 18, and the acquisition timing of the information on the printing plate 25 a of the printing plate 25 in the printing plate observation unit 26 is controlled by the control unit 18, and the acquired printing plate 25 a of the printing plate 25. Is stored in the storage unit 14.

When transparent ink such as an insulator is used for the ink, it is difficult to identify with the naked eye. However, the ink is identified by the line sensor by providing a polarizing filter in front of the light source and the line sensor and illuminating from two or more places. Can improve sex.
Further, acquisition of information on the plate surface 25a of the printing plate 25 is performed for each scan, so that it is possible to detect unevenness in film thickness due to landing position deviation, satellite, and ejection droplet amount change. For example, by measuring the relationship between the film thickness and the optical characteristic in advance and storing it in the storage unit 14, the film thickness is estimated by comparing the above-described relationship with the detected optical characteristic. Can do.

In addition, when silver nanoink is used as the ink, the silver nanoink exhibits silver luster as it dries and changes its color or reflectance. When the film thickness is thin, the drying is fast, and when it is thick, the drying is slow. Can be estimated.
In the case of a transparent ink such as an insulator, the film thickness can be determined by interference fringes. The film thickness can be estimated by measuring the relationship between the film thickness and the interference fringes in advance. In the case of ink having crystallinity such as semiconductor, a polarizing filter may be provided to estimate the film thickness by color. In this case as well, the film thickness can be estimated by measuring the relationship between the film thickness and the color in advance.

The stage 30 places the substrate 31 and moves in the transport direction V to transport the substrate 31 to a predetermined position. The stage 30 is provided with a transport mechanism (not shown). The transport mechanism is connected to the control unit 18, and the control unit 18 controls the transport mechanism to move the stage 30 in the transport direction V, thereby changing the position of the stage 30.
First, the stage 30 stands by at a start position Ps where the substrate 31 transported from the outside of the casing 20 is placed. Next, the stage 30 is moved to the printing position Pp below the plate cylinder 24. Next, after printing, the stage 30 is moved to the end position Pe with the printed substrate 31 placed thereon, and then the substrate 31 is taken out of the casing 20. The stage 30 is moved from the end position Pe to the start position Ps and waits until the substrate 31 is loaded.

The drying unit 32 dries the ink on the plate surface 25 a of the printing plate 25. As long as the ink can be dried, the drying method is not particularly limited, and examples thereof include hot air and cold air blowing by a fan, heating by an infrared heater, high-frequency irradiation, and microwave irradiation.
In addition, when the ink of the plate surface 25a of the printing plate 25 can be dried by natural drying, the drying unit 32 is not necessarily provided.

The ionizer 33 neutralizes static electricity on the plate surface 25 a of the printing plate 25. The ionizer 33 removes static electricity from the plate surface 25a of the printing plate 25 and suppresses adhesion of foreign matter such as dust and dirt to the plate surface 25a of the printing plate 25. Further, when the plate surface 25a of the printing plate 25 is charged, the ink may be bent. However, the ink can be prevented from being bent, and the ink jet ejection accuracy is improved.
As the ionizer 33, an electrostatic static eliminator can be used. For example, a corona discharge method and an ion generation method can be used. The ionizer 33 is provided on the downstream side in the Y direction of the drying unit 32. If the static electricity on the plate surface 25a of the printing plate 25 can be removed before recording by the image recording unit 22, the ionizer 33 is provided. The position is not particularly limited.

  The cleaning unit 34 removes ink attached to the plate cylinder 24 and the printing plate 25. The configuration of the cleaning unit 34 is not particularly limited as long as the ink attached to the plate cylinder 24 and the printing plate 25 can be removed. For example, the roller is pressed against the plate cylinder 24, the ink is transferred to the roller, and the transferred ink is wiped off.

  The maintenance unit 36 checks whether the discharge characteristics of the image recording unit 22 exhibit predetermined performance. The maintenance unit 36 wipes the nozzles so as to exhibit a predetermined performance. The maintenance unit 36 is provided at a position away from the plate cylinder 24. The image recording unit 22 is transferred to the maintenance unit 36 via a guide rail (not shown), for example. The maintenance unit 36 will be described in detail later.

Hereinafter, the image recording unit 22 will be described in detail.
FIG. 2 is a schematic diagram illustrating an image recording unit of the printing apparatus according to the embodiment of the present invention.
An image recording unit 22 using an inkjet method will be described as an example.
As shown in FIG. 2, the image recording unit 22 includes an inkjet head 40, an alignment camera 42, a laser displacement meter 44, a reading unit 47, and a rotating unit 49, which are provided on the carriage 46. ing. The carriage 46 can be moved in a direction parallel to the rotation shaft 24 b of the plate cylinder 24 by the linear motor 48, that is, the X direction, and the inkjet head 40 can be moved in the X direction by the carriage 46. The position of the carriage 46 can be calculated from a reading value of a linear scale (not shown) provided in the linear motor 48.

  The inkjet head 40 is provided with a discharge control unit 43 for controlling the discharge of ink. The ejection control unit 43 adjusts the ink ejection waveform. The discharge controller 43 is connected to the controller 18. In the discharge controller 43, for example, the user can adjust the discharge voltage or the discharge waveform through the user interface. As will be described later, the ink is ejected with its temperature adjusted.

  An alignment camera 42, a laser displacement meter 44 and a reading unit 47 are also connected to the control unit 18. The carriage 46 is provided with a drive unit (not shown) for moving in the Z direction. This drive unit is connected to the control unit 18, and the control unit 18 controls the movement of the carriage 46 in the Z direction. Is done. Here, the Z direction is a direction perpendicular to the surface 24 a of the plate cylinder 24.

The alignment camera 42 is for obtaining positional information of alignment marks for correcting ink ejection positions, ink ejection timings, and pattern data.
The configuration of the alignment camera 42 is not particularly limited as long as the alignment marks A to D can be detected.

The alignment camera 42 images the alignment marks A to D, stores the captured image data in the storage unit 14, and the determination unit 16d identifies the positions of the alignment marks A to D. The alignment camera 42 and the determination unit 16d function as an attachment position information acquisition unit that acquires attachment information of the printing plate 25 provided in the plate cylinder 24.
Based on the position information of the alignment marks A and B, information on the ink ejection start position in the Y direction, the enlargement / reduction of the printing plate in the X direction, and the inclination angle θ of the printing plate can be obtained. From the positional information of the alignment marks A and C, it is possible to obtain information about the ink ejection start position in the X direction and the enlargement / reduction information of the printing plate in the Y direction. For example, information on the trapezoidal distortion of the printing plate, that is, information on the trapezoidal deformation can be obtained from the position information of the alignment marks A to D. The ink discharge start position is called an inking start position.
In the printing plate 25, it is ideal that the line La passing through the alignment mark A and the alignment mark C is parallel to the Y direction. However, when the printing plate 25 is attached to the plate cylinder 24, the printing plate 25 is slightly inclined with respect to the plate cylinder 24. Based on the position information of the alignment marks A to D, the mounting information of the printing plate 25 on the plate cylinder 24, for example, the information such as the inclination of the printing plate 25 with respect to the Y direction of the plate cylinder 24 can be obtained.

The ink discharge start position, the position of the inkjet head 40, and the ink discharge timing are corrected based on the various information obtained above. Any of these corrections may be performed by a known correction method for ink droplet ejection by inkjet.
Further, known correction methods can be used for the enlargement / reduction in the X direction, the enlargement / reduction in the Y direction, the inclination, and the trapezoid correction of the pattern data.
Note that it is sufficient that there are at least three alignment marks, and information on enlargement / reduction of the printing plate in the X direction, inclination angle θ of the printing plate, and enlargement / reduction of the printing plate in the Y direction can be obtained. If there are four alignment marks, information on the trapezoidal distortion of the printing plate 25 can be obtained. Furthermore, by providing a plurality of alignment marks inside the alignment marks A to D, nonlinear correction can be performed. In this case, a known correction method can also be used for correction using the alignment mark.

  The laser displacement meter 44 measures the distance between the inkjet head 40 and the plate surface 25 a of the printing plate 25. The distance between the alignment mark A and the alignment mark C in the Y direction, that is, the AC length, changes due to the plate swelling caused by ink or the change in plate cylinder diameter + plate thickness due to temperature or the like. Here, since the ink of the ink jet head 40 is ejected at the timing of the pulse signal of the measurement unit 16a, it corresponds to the change of the plate length without receiving the change of the plate cylinder diameter. It will change.

In order to make the length of the printed pattern on the substrate 31 constant even when the AC length changes, the laser displacement meter 44 measures the change in the plate cylinder diameter + plate thickness. Correction is performed based on the measurement result.
As a specific example of the correction, the distance fluctuation from the rotation axis 24b of the plate cylinder 24 to the plate surface 25a of the printing plate 25 is accurately measured, and based on the result, the relative movement of the plate cylinder 24 and the substrate 31 at the time of transfer is measured. For example, changing the speed.
In addition to the specific examples of the correction described above, for example, the temperature of the plate cylinder 24 or the environment is measured, and the table of the relationship between the temperature and the distance between the rotation axis 24b of the plate cylinder 24 and the plate surface 25a of the printing plate 25 prepared in advance is used. Based on the above, it is possible to change the movement relative speed of the plate cylinder 24 and the substrate 31 during transfer.
According to the specific example of the correction described above, printing can be performed with high accuracy even if the plate swells or the plate cylinder diameter changes. It is known that when the transfer is performed, if the feed speed on the plate side is different from that on the substrate side, the dimension of the transfer pattern in the feed direction changes.

The configuration of the laser displacement meter 44 is not particularly limited as long as the distance between the inkjet head 40 and the plate surface 25a of the printing plate 25 can be measured.
Further, the laser displacement meter 44 can measure a change in the plate cylinder diameter + plate thickness by measuring the distance to the plate surface 25a of the printing plate 25. This can be used for enlargement / reduction in the Y direction. For example, when the diameter of the plate cylinder 24 or the film thickness of the printing plate 25 changes due to a temperature change, the length between the alignment mark A and the alignment mark C changes. This change in length can be used for pattern data correction.

The reading unit 47 ejects the mark 90 (see FIG. 9) in the alignment areas M ₁ , M ₂ , and M ₃ (see FIG. 5A) formed on the printing plate 25, which will be described later, and the mark 90. The position information of the plurality of ink landing positions is obtained, and the difference data between the mark position and the ink landing position in the Y direction is obtained.
The reading unit 47 includes, for example, a camera (not shown) including a CMOS or CCD having about 1 million pixels or more, and an image processing unit (not shown) connected to the camera. The image processing unit may be integrated with the camera or may be a separate body, and is provided, for example, in the adjustment unit 16b.
The reading unit 47 captures the image of the mark 90 and the image of the dot 92 (see FIG. 9) with a camera, acquires the image data of the mark 90 image and the dot 92 (see FIG. 9), and the image processing unit captures the mark 90. The position information and the position information of the dots 92 formed with ink as the landing position are obtained as coordinate data, for example. Then, the difference data between the position of the mark 90 and the dot 92 is obtained from the coordinate data of the position information of the mark 90 and the coordinate data of the position of the dot 92. Data on the difference between the position of the mark 90 and the dot 92 is obtained in the form of coordinate data or the number of pulses based on the pulse data based on the coordinate data output from the measuring device 37 of the plate cylinder 24. Data on the difference between the position of the mark 90 and the dot 92 is output to the adjustment unit 16b. In the adjustment unit 16b, corrected ejection timing data expressed by coordinate data or the number of pulses is created.

The image processing by the image processing unit in the reading unit 47 is the contour extraction of the mark 90, the contour extraction of the dot 92, and the calculation of the center line cm (see FIG. 9) of the mark 90 and the center position of the dot 92.
As the center line of the mark 90, for example, a rectangle that matches the mark 90 is obtained by regarding the outline of the mark 90 as a rectangle, and the bisector of the side in the Y direction of the rectangle is set as the center line.
The center position of the dot 92 is, for example, a circle that matches the dot 92 with the outline of the dot 92 regarded as a circle, and is set as the center position of the circle.
As for the image processing, a known one can be appropriately used as long as the contour extraction and the center position of the two-dimensional figure can be specified.
The position where the reading unit 47 is provided is not particularly limited as long as the alignment areas M ₁ , M ₂ , and M ₃ can be read. However, even if the relative position between the inkjet head 40 and the printing plate 25 is shifted due to vibration, the influence of the reading unit 47 on the carriage 46 is eliminated. .

  By using the alignment camera 42, the laser displacement meter 44, and the reading unit 47 as described above, alignment accuracy and ink ejection timing accuracy can be increased. The printing apparatus 10 is used for forming a thin film transistor as will be described later. In the thin film transistor, even a deviation of about 10 μm results in a characteristic different from the designed characteristic. When a plurality of thin film transistors are formed, the characteristics vary even if there is a deviation of about 10 μm. For example, when used for electronic paper, high performance cannot be obtained. Can be suppressed.

  The rotating unit 49 rotates the inkjet head 40 around a line perpendicular to the surface 24 a of the plate cylinder 24. The rotating portion 49 can match the orientation of the inkjet head 40 with the inclination of the printing plate 25.

As shown in FIG. 3A, the inkjet head 40 has a plurality of nozzles 41 arranged in a staggered manner over a length corresponding to the entire width of the printing plate 25.
By applying the staggered arrangement, the nozzles 41 can be arranged with high density. The number of rows in which the nozzles 41 are arranged is not particularly limited, and may be one row, two rows, or more. The nozzles 41 may be arranged in a matrix.
The configuration of the inkjet head 40 is not particularly limited, and for example, the configuration shown in FIG. The inkjet head 40 shown in FIG. 3B has a plurality of head modules 40a connected in the X direction. In this case, the configuration is not limited to a configuration in which the plurality of head modules 40a are connected in a row, and a configuration in which the plurality of head modules 40a are connected in a staggered manner may be used.
In the inkjet head 40 shown in FIG. 3B, the ejection waveform can be adjusted for each head module 40a by the ejection controller 43. Further, if the ejection control unit 43 is provided for each head module 40a, the ejection waveform can be adjusted for each ejection control unit 43.

  The method of ejecting ink from the ink jet head 40 is not particularly limited, and a piezoelectric method of ejecting liquid by utilizing flexural deformation, shear deformation, longitudinal vibration, etc. of the piezoelectric element, and heating the liquid in the liquid chamber by a heater Various methods such as a thermal method in which a liquid is ejected by utilizing a film boiling phenomenon and an electrostatic method in which an electrostatic force is utilized can be used.

Next, the ink supply mechanism of the printing apparatus 10 will be described.
FIG. 4 is a schematic diagram illustrating an ink supply mechanism of the printing apparatus according to the embodiment of the present invention.
As shown in FIG. 4, in the image recording unit 22, the inkjet head 40 has two sub tanks 50 and 58 connected to each other through pipes 50c and 58c, respectively. A deaeration unit 51 is provided in the pipe 50c. The deaeration unit 51 degass the ink supplied to the inkjet head 40, and a known unit can be used as appropriate.

The sub tank 50 stores ink to be supplied to the inkjet head 40. Two water level sensors 50a and a temperature adjustment unit 50b are provided.
The configuration of the water level sensor 50a is not particularly limited as long as the water level of the ink can be measured, and a known sensor can be appropriately used.
The temperature adjustment unit 50b is for adjusting the temperature of the ink. Thereby, the temperature of the ink can be adjusted. The temperature of the ink is preferably about 15 ° C. to 30 ° C., for example. The temperature adjustment unit 50b is not particularly limited as long as the temperature of the ink can be adjusted, and a known one can be used as appropriate.

The sub tank 58 stores ink collected from the inkjet head 40. Two water level sensors 58a and a temperature adjustment unit 58b are provided.
Since the water level sensor 58a has the same configuration as the water level sensor 50a, detailed description thereof is omitted. Since the temperature adjustment unit 58b has the same configuration as the temperature adjustment unit 50b, a detailed description thereof is omitted.

  There is a circulation unit 60 that moves the ink in the sub tank 58 to the sub tank 50. The circulation unit 60 includes a pipe 60c that connects the sub tank 50 and the sub tank 58, and a pump 60a and a filter 60b that are provided in the pipe 60c. The pump 60a is for adjusting the amount of ink in the sub tank 50 and the sub tank 58. If the pump 60a can move ink between the sub tank 50 and the sub tank 58, the structure will not be specifically limited, A well-known pump can be utilized suitably. The ink that moves from the sub tank 58 to the sub tank 50 passes through the filter 60b, and at this time, dust and the like are removed.

A pipe 64c is inserted into each of the sub tank 50 and the sub tank 58, and a pump 64a is provided in the pipe 64c. Further, a pressure sensor 64b is connected to the pipe 64c via a pipe 64d. Although not shown, the pipes 64c and 64d are provided with valves and the like. Thereby, the sub tanks 50 and 58 are filled with nitrogen gas. Further, by changing the filling amount of the nitrogen gas, a pressure difference can be generated between the sub tank 50 and the sub tank 58 and the gas can be easily circulated.
The pressure of the sub tank 50 and the sub tank 58 can be measured by the pressure sensor 64b. By using the measurement results of the pressures of the sub tank 50 and the sub tank 58 by the pressure sensor 64b, the meniscus negative pressure and the circulation amount of the inkjet head 40 can be controlled.

An ink tank 52 is connected to the sub tank 50 via a pipe 62b. The pipe 62b is provided with a pump 62a and a filter 62e. The ink tank 52 is filled with ink 52b.
The ink tank 52 is provided with a temperature adjustment unit 52a. Since the temperature adjustment unit 52a has the same configuration as the temperature adjustment unit 50b, a detailed description thereof will be omitted.
Further, for example, a cylinder 62c filled with nitrogen gas is connected to the ink tank 52 via a pipe 62d. As a result, the ink tank 52 is filled with nitrogen gas.

Further, a cleaning liquid bottle 54 is connected to the sub tank 50 via a pipe 62b. The pipe 62b is provided with a pump 62a and a filter 62e. The cleaning liquid bottle 54 is filled with a cleaning liquid 54b.
The cleaning liquid bottle 54 is provided with a temperature adjustment unit 54a. Since the temperature adjustment unit 54a has the same configuration as the temperature adjustment unit 50b, a detailed description thereof is omitted.
Further, for example, a cylinder 62c filled with nitrogen gas is connected to the cleaning liquid bottle 54 via a pipe 62d. As a result, the cleaning liquid bottle 54 is filled with nitrogen gas.
Although the temperature of the ink can be adjusted by the temperature adjustment unit 52a, the temperature of the ink is preferably the temperature of the ink in the sub tank 50> the temperature of the ink in the ink tank 52.

The sub tank 58 is connected to a waste liquid tank 56 through a pipe 62f. A pump 62a is connected to the pipe 62f. Thereby, the ink 52b in the sub tank 58 can be moved into the waste liquid tank 56 as waste liquid.
As the ink 52b, a nano metal ink for inkjet can be used. Specifically, ULVAC-made Ag nanometal ink (Ag1teH (model number), L-Ag1TeH (model number)) and Au nanometal ink (cyclododecene solvent) inkjet type can be used.

Next, the printing plate 25 will be described.
FIG. 5A is a schematic diagram illustrating an example of a printing plate used in the printing apparatus according to the embodiment of the present invention. FIG. 5B illustrates an example of the printing plate used in the printing apparatus according to the embodiment of the present invention. It is a typical sectional view shown.
As shown in FIG. 5A, for example, the printing plate 25 has alignment marks A to D provided at the four corners, respectively, an ejection confirmation area T, printing areas G ₁₁ and G ₁₂ , a spit area G, and printing. Areas G ₂₁ and G ₂₂ , a spit area G, printing areas G ₃₁ and G ₃₂ , and a discharge confirmation area T are formed. Further, alignment areas M ₁ and M ₃ are formed on both sides of the ejection confirmation area T, the printing areas G ₁₁ , G ₁₂ , G ₂₁ , G ₂₂ , G ₃₁ , G ₃₂ , and the spit area G, respectively. Alignment area _{M 2} is formed between the printing area _G 11 in the X _direction, and G _{21, G 31} and the printing area _{G 12, G 22, G 32} . Spit area G is divided by the alignment area M _2.
As described above, the alignment areas M ₁ , M ₂ , and M ₃ are formed to be separated from each other along the X direction. The alignment areas M ₁ , M ₂ , and M ₃ each have a plurality of areas divided in the Y direction, and have 8 areas, for example. Alignment area _{M 1} has a region _M 11 _{~M 18} of 8, the alignment area _{M 2} has a region _M 21 _{~M 28} 8, region _M 31 of the alignment area _{M 3} are 8 _{~M 38} Have

The ejection confirmation area T is an area where ink is ejected in a test pattern by the inkjet head 40. After the evaluation, the ink in the discharge confirmation area T is removed by the cleaning unit 34 or transferred to the substrate 31 and removed.
The spit area G is an area that is used for ejection confirmation by ejecting ink by the inkjet head 40 in a normal ejection operation.
Before printing area _{G 11 ~G 31, G 12 ~G} 32 , area for discharging confirm, by providing the discharge check area T and spit area G, the printing area _{G 11 ~G 31, G 12 ~G} 32 It is possible to reliably discharge the ink.

The alignment areas M ₁ , M ₂ , and M ₃ are for checking the ink landing position and checking the ink discharge timing, and the mark 90 is formed. A plurality of inks are deposited on the alignment areas M ₁ , M ₂ , and M ₃ .
There are three alignment areas M ₁ , M ₂ , and M ₃ , but the present invention is not limited to this. If there are a plurality of alignment areas, for example, three or more, the ink position detection accuracy can be improved. .
By setting the alignment areas M ₁ , M ₂ , and M ₃ in a plurality of locations in the X direction, comparison with different nozzles becomes possible. In particular, this is effective because more nozzles can be selected in the case of a line-type inkjet head. In addition, the inclination between the inkjet head 40 and the printing plate 25 can be detected at the same time.
Further, the alignment areas M ₁ , M ₂ , and M ₃ can cope with nonlinear deformation in the Y direction by setting the Y direction as a plurality of regions. In particular, when the plate cylinder method is used, since there is a non-linear deformation in the Y direction due to various factors as described above, correction including this can be performed. The alignment areas M ₁ , M ₂ , and M ₃ will be described in detail later.

As shown in FIG. 5B, for example, the printing plate 25 has a recess 25b. The ink 52b is ejected onto the recess 25b to apply the pattern ink. The recess 25b is lyophilic with respect to the ink 52b. The depth of the recess 25b is about several μm.
The printing plate 25 is not limited to materials such as resin, metal, and glass. However, if a resin plate is used, it is elastic and the printing pressure can be lowered, so that it is easy to print on a brittle material such as glass. As the printing plate 25, various elastomers such as fluorosilicone rubber, butyl rubber, ethylene propylene rubber, nitrile rubber, neoprene rubber, high-baron rubber, urethane rubber, etc. can be used, but silicone such as PDMS (polydimethylsiloxane) having good releasability Rubber, fluororubber and the like are desirable. By using PDMS (polydimethylsiloxane) or the like, transferability is improved. After transfer, ink is suppressed from remaining on the printing plate 25, and continuous printing can be performed without washing the printing plate 25. Thereby, printing efficiency can be improved.
In addition, although the printing plate 25 uses what the recessed part 25b was formed in the predetermined pattern shape, the recessed part 25b is formed by a well-known method. For example, the printing plate 25 is formed by a general method, and is formed by using a method similar to, for example, photolithography, imprint, offset printing plate, and flexographic printing plate.

FIG. 6 is a schematic diagram illustrating an example of a maintenance unit of the printing apparatus according to the embodiment of the present invention.
As shown in FIG. 6, a rotating roller 70 is disposed with respect to the inkjet head 40. The rotating roller 70 has a rotating shaft 70a and rotates around the rotating shaft 70a. A web 72 for cleaning the inkjet head 40 is wound around the circumferential surface 70 b of the rotating roller 70. The web 72 is not particularly limited as long as the ink 52b of the inkjet head 40 can be removed. For example, the cleaning liquid 74a is directly applied or sprayed to the inkjet head 40 by the cleaning unit 74, and the rotary roller 70 is rotated to bring the web 72 into contact with the inkjet head 40 to remove the ink 52b. Alternatively, the cleaning liquid 74a may be sprayed onto the web 72 by the cleaning unit 74, and the rotary roller 70 may be rotated to bring the web 72 into contact with the inkjet head 40 to remove the ink 52b.

As the cleaning liquid, for example, a solvent that does not contain solid components among ink-soluble solvents or ink components is used. Hydrocarbon solvents can be used for the ULVAC Ag nanometal ink (Ag1teH (model number), L-Ag1TeH (model number)) and Au nanometal ink (cyclododecene solvent) inkjet type. As the hydrocarbon solvent, for example, toluene, xylene, hexane, tetradecane, and cyclododecene can be used.
The web 72 includes, for example, a wiping cloth such as KB Seiren, Savina (registered trademark), Toray, Toraysee (registered trademark), Teijin Limited, Nanofront (registered trademark), Microstar (registered trademark), etc. Can be used.

Moreover, as what cleans the inkjet head 40, it is not limited to what is shown in FIG. For example, it can also be set as the structure which has a rubber blade (not shown). Since the inkjet head 40 can be moved in the X direction by the carriage 46, the rubber blade is fixed and the ink is wiped in the longitudinal direction of the inkjet head 40 using this. Alternatively, the inkjet head 40 may be fixed and the rubber blade may be scanned and wiped. At this time, wiping the ink in a short direction perpendicular to the longitudinal direction of the inkjet head 40 has an advantage that the moving distance of the rubber blade can be shortened. Besides this, the possibility that the wiped ink enters another nozzle is small There are benefits. On the other hand, if the ink is wiped off in a direction parallel to the longitudinal direction of the inkjet head 40, there is an advantage that the X axis of the inkjet head 40 can be shared. Therefore, it is preferable to design in an optimum form considering the device configuration or cost.
Note that a cleaning liquid may be applied to the rubber blade or the inkjet head 40 to wipe off the ink. When the ink is wiped off, the pressure in the sub tanks 50 and 58 can be set separately from the pressure during printing. It is preferable to set an optimum pressure according to the conditions of the ink, the inkjet head 40 or the wipe.

When using a web (not shown), the web is moved and wiped while moving the inkjet head 40 in the X direction, for example. This constantly refreshes the web surface. The same web as the above-described web 72 can be used.
It should be noted that at least one of cleaning the web in advance and wiping the ink, and applying the cleaning liquid to the inkjet head 40 and wiping the ink may be performed. When wiping ink, the pressure in the sub tanks 50 and 58 can be set separately from the pressure during printing. It is preferable to set an optimum pressure according to the conditions of the ink, the inkjet head 40 or the wipe.

The maintenance unit 36 can also perform operations such as purge, spit and drip on the inkjet head 40.
Here, purging means that the ink jet head 40 is disposed on the ink receiver 77 and the pressure of the sub tank 50 is set to a positive pressure in this state to push out ink from the nozzle 41. The ink receiver 77 can be shared with the cap and the wiper.

  A spit is a discharge operation. Thereby, nozzle clogging and discharge bending can be improved. The spit is performed at the same place as the purge, but a spit station may be provided. In this case, it is preferable to perform suction from below so that the ejected ink does not fly. At the time of spit, the drive voltage is made higher than the ejection waveform for the inkjet head 40 during printing, or a dedicated waveform is used. The dedicated waveform is set so that the amount of ink droplets is larger and the ink ejection speed is faster than the ejection waveform during printing.

  The drip is not a recovery operation in which the ink is strongly pushed out as in the above-described purge, but an operation in which the ink is recovered by dripping slowly. As a result, nozzle clogging and ink ejection bending can be improved. The drip is also performed at the same place as the purge or spit, but the drip is performed by setting the pressure in the sub tank 50 to the positive pressure side than the pressure during printing. However, it is preferable that the pressure in the subtank 50 is more positive than atmospheric pressure and lower than the purge pressure.

  Further, the maintenance unit 36 may have a cap mechanism (not shown) for preventing the nozzle 41 from drying. In the cap mechanism, after the nozzle 41 is capped, the periphery of the nozzle 41 is filled with nitrogen gas. Further, the nozzle 41 can be further prevented from drying by immersing the cleaning liquid in a web or the like and disposing it in the cap.

FIG. 7 is a schematic diagram illustrating the discharge observation unit and the nozzle observation unit of the maintenance unit of the printing apparatus according to the embodiment of the present invention.
As shown in FIG. 7, in the maintenance unit 36, the ejection observation unit 76 that observes the ink droplets 45 ejected from the inkjet head 40 and the nozzle 41 (see FIG. 3A) of the inkjet head 40 are replaced with the nozzle 41. And a nozzle observation part 78 for observing from the surface side on which the is formed. An ink receiver 77 that receives the ink droplet 45 is provided opposite the inkjet head 40.

The ejection observation unit 76 includes a light source 76a and an imaging unit 76b, and the light source 76a and the imaging unit 76b are arranged with the ink droplet 45 interposed therebetween. An LED light source and a strobe light source can be used as the light source 76a. As the strobe light source, for example, a nano pulse light manufactured by Ebara Corporation can be used.
For example, a camera including a camera lens can be used as the imaging unit 76b. As the camera lens, for example, a camera lens having an optical magnification of 0.5 to 10 times and a working distance of 30 mm or more is used. As the camera, for example, a camera having a monochrome CMOS or CCD having about 1 million pixels or more is used. The discharge observation unit 76 does not need to be a color in order to observe the shadow of the discharged ink droplet 45.

In the nozzle observation unit 78, one end of a lens 78b is connected to the imaging unit 78a, and a light source 78c is provided at the other end of the lens 78b.
For the imaging unit 78a, for example, a camera having a CMOS or CCD with about 1 million pixels or more is used, and both color and monochrome can be used.
For example, a camera lens having an optical magnification of 0.5 to 10 times is used as the lens 78b. Since ink may adhere to the camera lens, it is desirable to provide a protective filter that can be easily replaced or cleaned.
The imaging unit 78a and the lens 78b may be integrated or separated. In the case of integration, for example, a camera provided with a camera lens can be used.
As the light source 78c, for example, an LED (light emitting diode) light source can be used, and coaxial illumination, ring illumination, or the like can be used.

  The discharge observation unit 76 and the nozzle observation unit 78 are both connected to the control unit 18, and the operations of the light sources 76a and 78c and the imaging units 76b and 78a are controlled by the control unit 18 and obtained by the imaging units 76b and 78a. The captured image data is stored in the storage unit 14 by the control unit 18. The control unit 18 compares the ink ejection state of the inkjet head 40 with, for example, the design value of the ejection characteristics of the inkjet head 40, and the comparison result is stored in the storage unit 14.

In the printing apparatus 10 of the present invention, for example, a gate electrode, a source electrode, and a drain electrode of a thin film transistor used for electronic paper or the like can be manufactured.
FIG. 8 is a schematic diagram illustrating an example of a thin film transistor formed by the printing apparatus according to the embodiment of the present invention.
8 includes a gate electrode 82, a gate insulating layer (not shown), a source electrode 86a, a drain electrode 86b, a semiconductor layer (not shown), and a protective layer. (Not shown).
In the TFT 80, a gate insulating layer (not shown) is formed so as to cover the gate electrode 82. A source electrode 86 a and a drain electrode 86 b are formed on the gate insulating layer with a gap set in advance as a channel region 84. A semiconductor layer (not shown) that functions as an active layer is formed on the channel region 84. A protective layer (not shown) is formed to cover the semiconductor layer, the source electrode 86a, and the drain electrode 86b. The channel length of the channel region 84 is on the order of several μm to several tens of μm. The drain current of the thin film transistor is affected by the channel length, and the variation in the channel length leads to the variation in the characteristics of the thin film transistor.

Next, adjustment of ink ejection timing in the printing apparatus 10 will be described.
In the digital inking method, it is important to ink the printing plate 25 accurately.
There is a limit to the resolution of a measuring device such as a rotary encoder that controls ink ejection timing, a digital error occurs, and the long dimension accuracy decreases as an accumulated error. For example, when inking at a resolution of 1200 dpi (dots per inch), it is necessary to ink at intervals of 21.166... If the encoder 1 pulse distance is 1 μm, either 21 pulses, ie, 21 μm, ejects ink once, or 22 pulses, ie, 22 μm, ejects ink once. For this reason, the error in discharging one ink is small, but this error is accumulated in consideration of inking in a large area. For example, when 254 mm is inked at 1200 dpi, the number of dots is 12,000. The actual inking distance is 21 μm (21 pulses) × 12000 = 252 mm when 21 pulses are discharged once, resulting in a deviation of 2 mm. The 2 mm misalignment may not be a big problem in the graphic field such as posters and leaflets, but in the printed electronics field, a 1-10 μm level alignment and a 1-10 μm wide wiring pattern are required. The deviation of 2 mm is extremely large. In the digital inking method, the printing plate 25 and the ink position are greatly displaced.

The solution in the ideal system is, for example, as disclosed in Patent Document 2 described above, grasping two alignment mark positions and adjusting with correction pulses when the accumulated error exceeds the resolution of the encoder. That is.
However, it takes 0.2 ms, for example, when the ejection speed is 5 m / s and the distance between the nozzle and the printing plate 25 is 1 mm after the ejection signal is input until the ink is deposited on the printing plate 25. For this reason, the reading position on the rotary encoder, the discharge timing, and the landing position do not match. Therefore, a slight fluctuation of the plate feed shifts the landing position. In particular, when the substrate is not flat and is wound around the plate cylinder, even if the rotary encoder does not fluctuate, the feed amount varies depending on the eccentricity of the plate cylinder 24 or the film thickness unevenness of the printing plate 25. Further, the roundness of the plate cylinder 24, unevenness in the feeding speed of the plate cylinder 24, plate deformation when the printing plate 25 is wound around the plate cylinder 24, distortion of the plate cylinder 24 or the printing plate 25 due to temperature and humidity, or printing Even when the printing plate 25 is deformed by swelling due to the ink solvent absorbing the ink solvent, the reading position, the discharge timing, and the landing position on the rotary encoder do not match. Further, the positional relationship between the printing plate 25 and the inkjet head 40 may be shifted due to vibration.

FIG. 9 is a schematic diagram showing a first example of a mark serving as a reference for the ink landing position formed on the printing plate. In the following description, the alignment areas M _{1 to} M ₃ will be described using the alignment area M ₁ as an example, but the same applies to the alignment areas M ₂ and M ₃ .
The alignment area M ₁ as shown in FIG. 9, the mark 90 as a reference for dripping position of the ink along the Y direction, and is formed of a plurality at equal intervals. The mark 90 serves as a reference for the ink landing position. For example, the mark 90 has a rectangular shape in which long sides are arranged perpendicular to the Y direction. A region where the mark 90 is formed is a mark formation region 27a. There is an ink landing area 27b where ink is deposited alongside the mark forming area 27a. In the ink landing region 27b, for example, three inks are deposited side by side in the X direction to form dots 92.

The marks 90 are formed with a pitch of 20 μm in the Y direction, for example. The rotary encoder is 1 pulse and 1 μm. In this case, as a design value, ink is ejected once with 20 pulses. That is, ink is ejected at a pitch of 20 μm, and the length is 300 mm and 15000 pixels. At this time, the number of pulses is 300,000.
In FIG. 9, the difference Δ1 between the top mark 90 and the dot 92 in the Y direction is −35 pulses, and the difference Δ2 between the bottom mark 90 and the dot 92 in the Y direction is −100 pulses.
Note that the negative values of the differences Δ1 and Δ2 in the Y direction mean that the dot 92 is on the opposite side of the Y direction with respect to the mark 90 in FIG. That is, the dot 92 is above the mark 90.

When inking a length of 300 mm that is inked at 1200 dpi described above, if ink is ejected once with 20 pulses, 300 mm is insufficient, and if ink is ejected once with 21 pulses, it becomes 315000 pulses, exceeding 300 mm. In this case, the adjustment unit 16b obtains the ink ejection timing with the smallest error with respect to the inking length by mixing 20 pulses and 21 pulses, and adjusts the ink ejection timing. As a method of adjusting the ink ejection timing, a method of thinning out the ink ejection so that the error is minimized at the inking length of 300 mm can be used. In this case, a known method can be used as appropriate, and for example, the method disclosed in JP-A-2005-246123 can be used.
In addition to this, it is also possible to set a discharge interval of ink to be used in advance, calculate a combination having the smallest error with respect to the length of inking the combination of the discharge intervals, and use this combination. . In addition, a method capable of eliminating a digital error due to the resolution of inking such as 1200 dpi and the resolution of the measuring device 37 such as a rotary encoder can be appropriately used.

Here, the mark 90 is not particularly limited, but is configured to be optically readable, for example. For example, the mark 90 is formed in the same intaglio structure simultaneously with the formation of the printing pattern of the printing plate 25. If the mark 90 is an intaglio, the mark 90 becomes a recess and the mark formation region 27a becomes a protrusion.
The printing plate 25 is formed by a general method as described above. Further, by using the method described in the above-mentioned Japanese Patent Application Laid-Open No. 2005-81726, in addition to forming the mark 90 with unevenness, it is also possible to form an ink having lyophilicity and liquid repellency with respect to the ink. it can.

The difference in the Y direction is the difference between the mark position and the ink landing position in the Y direction. As described above, the data of the difference between the mark position and the ink landing position is acquired by the reading unit 47 as follows.
First, the mark 90 is photographed and the position information of the mark 90 is acquired. Specifically, the position of the mark 90 is read, a center line cm in the Y direction is obtained, and this center line cm is used as a reference.
The position of the dot 92 represents the ink landing position. The three dots 92 are photographed, the position information of the three dots 92 is acquired, and the position information of the three ink landing positions is acquired. The average value cd of the center positions of the three dots 92 in the Y direction is used as a reference. The difference between the center line cm of the mark 90 in the Y direction and the average value cd of the center positions of the dots 92 in the Y direction is obtained. Data representing this difference is obtained.
Since the method for obtaining the center line of the mark 90 and the center position of the dot 92 is as described above, detailed description thereof is omitted.

The marks in the printing apparatus 10 are not limited to those shown in FIG. Further, although the ink is ejected adjacent to the mark 90, the ink may be ejected into the mark 90. Here, FIG. 10 is a schematic diagram showing a second example of a mark serving as a reference for the ink landing position formed on the printing plate.
In Figure 10, the alignment area M _1, mark 90a~90e for changing an arrangement position in the Y direction with respect to the discharge interval P1 designed along the Y direction, are formed at predetermined arrangement intervals . The arrangement positions of the marks 90a to 90e are not an integral multiple of the ink ejection interval P1. Symbol Ep is a discharge position set as a design value. The marks 90a to 90e serve as a reference for the ink landing position.
Ink is ejected from the inkjet head 40 to the marks 90 a to 90 e to obtain dots 92. Data on the difference between the arrangement positions of the marks 90a to 90e and the positions of the dots 92 is obtained as described above. In the example of FIG. 10, there are dots 92 in the mark 90c, and the position of the mark 90c is the best ink ejection timing. Data of the difference between the position of the mark 90c and the position of the dot 92 at this time is calculated in the form of the number of pulses. Then, based on the above-described best ejection timing, the ink ejection timing is adjusted as described above. In this manner, the positional relationship between the mark position and the ink landing position can be easily calculated by arranging the mark arrangement position at a position slightly shifted in the Y direction.
Although the marks 90a to 90e are formed along the Y direction, the present invention is not limited to this, and the marks 90a to 90e may be formed side by side in the X direction.

Further, as shown in FIG. 11, the marks 94a to 94e may be formed obliquely rather than perpendicular to the Y direction. The marks 94a to 94e serve as references for ink landing positions.
Here, FIG. 11 is a schematic diagram showing a third example of a mark serving as a reference for the ink landing position formed on the printing plate.
In Figure 11, the alignment area _{M 1,} mark 94a~94e with different angles with respect to the Y direction is formed along the Y direction. The center position of the marks 94a to 94e in the X direction is an integral multiple of the ink ejection interval P1. Symbol Ep is a discharge position set as a design value.

Ink is ejected to the marks 94a to 94e to obtain dots 92. Data on the difference between the positions of the marks 94a to 94e and the positions of the dots 92 is obtained as described above. In the example of FIG. 11, the difference in the position of the dot 92 is small with respect to the position of the mark 94e, that is, the difference in the Y direction is small, and the position of the mark 94e is the best ink ejection timing. Data of the difference between the position of the mark 94e and the position of the dot 92 at this time is calculated in the form of the number of pulses. Then, based on the above-described best ejection timing, the ink ejection timing is adjusted as described above. In this way, by arranging the mark so as to be inclined with respect to the Y direction, the positional relationship between the mark and the ink landing position can be easily calculated.
The marks 94a to 94e are formed along the Y direction. However, the marks 94a to 94e are not limited to this and may be formed side by side in the X direction.

Here, FIG. 12 is a schematic diagram showing a fourth example of a mark serving as a reference of the ink landing position formed on the printing plate. FIG. 12 shows that time has passed as the mark moves from the left to the right.
In Figure 12, the alignment area M _1, mark 96a~96e for changing an arrangement position in the Y direction with respect to the discharge interval P1 designed is formed along the Y direction. The arrangement positions of the marks 96a to 96e are not an integral multiple of the ink discharge interval P1 as in the marks 90a to 90e. Symbol Ep is a discharge position set as a design value. Further, the portion 97 other than the marks 96a to 96e is an ink repellent portion that is liquid repellent with respect to ink and repels ink. For example, the marks 96a to 96e are concave portions, and the portion 97 other than the marks 96a to 96e is a convex portion.
The marks 96a to 96e serve as a reference for ink landing positions. A portion 97 other than the marks 96a to 96e corresponds to the mark forming region 27a.
In this case, when the ink is ejected to the marks 96a to 96e, even if the dots 92 are formed in a shifted manner as in the marks 90a, 90b, 90d, and 90e, the portion 97 repels the ink. The dots 92 fit within the marks 90a, 90b, 90d, and 90e. For this reason, there is no difference from the mark 90c that is in timing, and it is not possible to obtain accurate data on the difference between the mark position and the dot position. In this way, by setting the portion 97 to repel ink, the ink moves to the mark even if the ink is deposited slightly deviating from the mark. For this reason, it is preferable that the portion 97 outside the marks 96a to 96e does not repel ink.

In addition, liquid repellency with respect to ink and lyophilicity with respect to ink can be evaluated as follows.
Droplets are deposited on a region where liquid repellency is expected and a region where lyophilicity is expected, and evaluation is performed based on the behavior of the droplets. A region where the droplet amount is reduced with respect to the droplet amount upon landing is an ink repellent portion having liquid repellency, and a region where the droplet amount is increased is a lyophilic ink portion having lyophilic property.
In the plate making process, liquid repellency and lyophilicity are imparted. In this case, the evaluation of the liquid repellency and the lyophilic property is performed by making droplets land on the boundary between the liquid repellant ink repellant portion and the lyophilic parent ink portion and evaluating the behavior of the liquid droplets. A region where the droplet amount has decreased with respect to the droplet amount upon landing is liquid repellent, and a region where the droplet amount has increased is lyophilic.
In the case where the uneven boundary of the plate coincides with the boundary of the liquid repellent ink repellent portion and the lyophilic parent ink portion, the boundary can be distinguished from the unevenness. When it is difficult to distinguish the boundary due to the small plate unevenness, it is possible to evaluate the change in the droplet amount at the boundary by causing a plurality of droplets to land near the boundary. Further, the boundary can be known by providing in advance an alignment mark indicating the uneven surface of the plate.

Here, FIG. 13 is a schematic diagram showing a fifth example of a mark serving as a reference for the ink landing position formed on the printing plate.
FIG. 13 is different from FIG. 12 in that the marks 96a to 96e and the other portion 27c have the same liquid repellency with respect to the ink, and the other configurations are the same as the components shown in FIG. It is. Therefore, in FIG. 13, the same components as those in FIG. 12 are denoted by the same reference numerals, and detailed description thereof is omitted. In this case, for example, the portion 27c other than the marks 96a to 96e is a convex portion. The portion 27c other than the marks 96a to 96e corresponds to the mark formation region 27a.
As shown in FIG. 13, the marks 96a to 96e and the portions 27c other than the marks 96a to 96e are made to have the same liquid repellency so that ink is repelled as ink repellent portions. As a result, when the dots 92 are formed so as to be shifted as in the marks 90a, 90b, 90d, and 90e, the dots 92 are shifted even when time elapses. The mark 90c has a timing, and the dot 92 remains within the mark 90c even when time elapses. As a result, accurate difference data between the mark position and the dot position can be obtained, and the ink ejection timing can be adjusted with high accuracy.

Here, FIG. 14 is a schematic diagram illustrating a sixth example of a mark serving as a reference for the ink landing position formed on the printing plate.
14, marks 96a to 96e are ink repellent portions that are liquid repellent with respect to ink, and portions 99 other than marks 96a to 96e are lyophilic with respect to ink. The other structure is the same as each structure shown in FIG. Therefore, in FIG. 13, the same components as those in FIG. 12 are denoted by the same reference numerals, and detailed description thereof is omitted. In this case, the marks 96a to 96e are convex portions, and the portion 99 other than the marks 96a to 96e is a concave portion. The portion 99 other than the marks 96a to 96e corresponds to the mark formation region 27a.
As shown in FIG. 14, the marks 96 a to 96 e flip ink, and the portions 99 other than the marks 96 a to 96 e do not flip ink. As a result, when the dots 92 are formed in a shifted manner as in the marks 90a, 90b, 90d, and 90e, the dots 92 move to the portion 99 as time elapses. The mark 90c has a timing, and the dot 92 remains within the mark 90c even when time elapses. Only when the ink landing position coincides with the mark 90c, the ink is stably placed on the mark 90c and the dot 92 is formed. Thereby, data of the difference between the mark position and the dot position can be obtained with higher accuracy, and the ink ejection timing can be adjusted with higher accuracy.

Next, the inclination correction of the printing plate 25 in the printing apparatus 10 will be described.
FIG. 15 is a schematic diagram illustrating an example of inclination correction of the printing apparatus according to the embodiment of the present invention.
In FIG. 15, the ideally arranged printing plate 25 i is indicated by an imaginary line. The ideal arrangement means that the line La passing through the Y direction of the plate cylinder 24 and the alignment mark A and alignment mark C of the printing plate 25 is parallel to the Y direction described above. FIG. 15 shows a state in which the printing plate 25 is arranged at an angle α with respect to the ideally arranged printing plate 25i.

Inclination occurs when the printing plate 25 is attached to the plate cylinder 24. When the printing plate 25 is mounted rotated at an angle α, the feed amount in the Y direction does not match the length in the Y direction of the pattern.
In this case, first, the inclination of the printing plate 25 is calculated. By specifying the two positions of the alignment mark A and the alignment mark C, the inclination of the printing plate 25, that is, the angle α can be calculated. More preferably, it is performed by comparing the mark 90 and the ink landing position as described above. Thereby, it is possible to correct the inclination of the printing plate 25 including the error of the ink jet ejection.
For example, as shown in FIG. 15, the marks 140 a, 140 b and 140 c for detecting the inclination of the printing plate 25 are straight lines extending parallel to the sides of the printing plate 25. Each of the marks 140a to 140c may be a single straight line or may be divided into a plurality of regions.
Further, the marks 140a to 140c are not limited to being the same, and the angles may be different from each other. By providing the marks 140 a to 140 c having different angles, for example, if ink has landed on the entire area of one mark, it can be seen that the angle of the mark is the inclination angle of the printing plate 25.

Ink is deposited by the inkjet head 40 so as to match the marks 140a, 140b, and 140c, and the inclination of the printing plate 25 is calculated. In order to make the ink landing position more accurate, the marks 140a to 140c are set as ink repellent portions and the portions other than the marks 140a to 140c are set as parent ink portions as described above. Thereby, it is possible to exclude the ink that has not landed on the marks 140a to 140c from forming dots at the marks 140a to 140c.
If the inclination of the printing plate 25 is an angle α, the feed amount in the Y direction is L · cos θ, while the length in the Y direction is L. The output interval of the encoder signal is also shifted by cos α. What is necessary is just to calculate the ink ejection timing in consideration of these.
In this case, the length in the Y direction matches the printing plate 25 and the inkjet head 40, but a deviation occurs in the X direction. This can be dealt with by tilting the inkjet head 40 as much as the tilt of the printing plate 25 and relatively moving the inkjet head 40 and the printing plate 25 in the X direction.
The ink drops on the marks 140a to 140c are photographed by the reading unit 47 and subjected to image processing and the like. The output interval of the encoder signal is adjusted at 16c.

  Further, when the reading unit 47 is scanned in the X direction, the ink ejection timing of the nozzles on both sides of the inkjet head 40 is deviated, so that the ink landing position is deviated in the Y direction, and the pattern is accurately applied to the printing plate 25. I cannot inking. For this reason, the ink ejection timing of the nozzles on both sides of the inkjet head 40 is adjusted by the adjustment unit 16b. Further, the inkjet head 40 is rotated in accordance with the inclination angle α of the printing plate 25. Thereby, the deviation of the ink landing position in the Y direction can be suppressed. That is, the inclination of the printing plate 25 can be corrected.

In addition to the above, the same can be done by rotating an image pattern to be ejected by ink jet. For example, when the printing plate 25 is inclined at the angle α, the pattern data of the pattern 89 to be formed is corrected by cos α times by the correction unit 16c. The ink ejection pattern data is corrected to generate correction pattern data. A pattern is formed using this correction pattern data.
In addition, by preparing a plurality of marks 140 a to 140 c and selecting a mark corresponding to the inclination of the printing plate 25, it is possible to suppress a reading length shift in the reading unit 47.

  More specifically, with respect to the correction of the inclination of the printing plate 25, for example, as shown in FIG. 16A, the printing plate 25 is inclined, and the wiring pattern 89a parallel to the rotation direction Y corresponds to the printing start position 89s. In the case where the wiring pattern 89a is displaced by 40 μm in the X direction from the printing end position 89e, in order to produce this wiring pattern 89a by inking with one nozzle 41b, the position of the nozzle 41b is aligned with the 40 μm displacement of the wiring pattern 89a. Must be moved in the Dh direction parallel to the X direction, for example. That is, it is necessary to move the inkjet head 40 in the Dh direction. In FIG. 16A, the symbol Hy indicates the moving direction of the nozzle 41b when the inkjet head 40 is not moved in the Dh direction. The moving direction Hy is a direction parallel to the Y direction. Reference numeral Hm indicates the moving direction of the nozzle 41b when the inkjet head 40 is moved in the Dh direction. The moving direction Hm is a direction parallel to the X direction.

  For example, as shown in FIG. 16B, when the printing plate 25 is tilted and the inkjet head 40 in which the nozzles 41 are arranged in a staggered manner is used, when the inkjet head 40 is tilted, the interval between the nozzles 41 is increased. t1 and t2 are t1 <t2, and the intervals of the nozzles 41 are not uniform. For this reason, it is necessary to move the inkjet head 40 in, for example, the Dh direction so that the inkjet head 40 is always disposed at a fixed location with respect to the inclined printing plate 25. Specifically, when the position of the inkjet head 40 is fixed, if the printing plate 25 is inclined, the printing plate start position 25s and the printing plate end position 25e are shifted from each other by a distance Dw. For this reason, by moving the inkjet head 40 in the Dh direction according to the amount of movement of the printing plate 25 in the Y direction, the inkjet head 40 can always be arranged at a fixed location with respect to the printing plate 25.

As described above, by correcting the inclination of the printing plate 25 by using the method of correcting the inclination of the printing plate 25, even if the printing plate 25 is mounted with an inclination, it is possible to suppress the deviation of the ink droplet ejection position and A pattern can be formed on the printing plate 25 with high accuracy without changing the size and position. Thereby, even if the mounting accuracy of the printing plate 25 is low, the printing accuracy can be improved.
As described above, an allowable range may be set for the inclination of the printing plate 25, and the inclination correction of the printing plate 25 may not be performed as long as it is within the allowable range.

Next, a wiring pattern formed by the printing apparatus 10 will be described.
Here, FIGS. 17A to 17C are schematic cross-sectional views showing the steps of forming the wiring pattern formed by the printing apparatus according to the embodiment of the present invention in the order of steps. FIG. 18A is a schematic cross-sectional view showing a first example of a printing plate before transfer, and FIG. 18B is a schematic cross-sectional view showing a pattern after transfer to the printing plate. FIG. 19A is a schematic cross-sectional view showing a second example of a printing plate before transfer, and FIG. 19B is a schematic cross-sectional view showing a pattern after transfer to the printing plate. FIG. 20A is a schematic cross-sectional view showing a third example of the printing plate before transfer, and FIG. 20B is a schematic cross-sectional view showing an example of the pattern after transfer to the printing plate. c) is a schematic cross-sectional view showing another example of the pattern after being transferred to the printing plate.

In the wiring pattern formed by the printing apparatus 10, as shown in FIG. 17A, the ink 52 b is ejected onto the concave portion 25 b of the printing plate 25, and the ink shape has the concave portion 110 at the center. In this state, as shown in FIG. 17B, when the printing plate 25 is pressed against the substrate 31 and the ink is transferred to the surface 31a of the substrate 31 as shown in FIG. Is formed.
The shape of the ink on the printing plate 25 and the shape of the wiring pattern 120 are, for example, a confocal microscope (OPTELICS H1200, manufactured by Lasertec), and a fine shape measuring machine surf coder (ET4000-L, manufactured by Kosaka Laboratory). Can be measured.

It was found that the wiring pattern 120 (see FIG. 17C) formed as described above was transferred to the surface 31a of the substrate 31 with the ink shape before transfer on the printing plate 25 as it was. For example, in the case where the ink shape is the printing plate 25 and there is a concave portion 110 in the center as shown in FIG. 17A, or in the case of a so-called coffee stain shape, the substrate 31 is also shown in FIG. The wiring pattern 120 had a concave 122 at the center, that is, a so-called coffee stain shape.
Since the wiring pattern 120 is formed by being transferred from the plate cylinder 24 to the substrate 31, the wiring pattern 120 may be a shape obtained by reversing the shape of the printing plate 25, but this is not the case. Although the mechanism of transfer to the substrate 31 is not clear, since PDMS (polydimethylsiloxane) is used for the printing plate 25, the PDMS (polydimethylsiloxane) is deformed by the printing pressure at the time of transfer, and the substrate and This is probably because the ink and the printing plate (PDMS (polydimethylsiloxane)) are in close contact.
This suggests that the cross-sectional shape of the wiring pattern can be freely controlled by controlling the ink shape on the printing plate before transfer.
It is known that the coffee stain is controlled by changing the volatilization state of the ink, and it is shown that the shape corresponding to the specification of the wiring pattern is possible by the ink design. PDMS (polydimethylsiloxane) is known to absorb solvents, and the same effect can be obtained by controlling the amount of absorption.

For example, as shown in FIG. 18A, when the surface 52 of the ink 52b is flat on the printing plate 25 and the surface 112 is flat, a wiring pattern having a flat surface on the surface 31a of the substrate 31 as shown in FIG. 124 is formed.
For example, as shown in FIG. 19A, when the surface 52 of the ink 52b is convex on the printing plate 25 and the surface 114 is convex, the surface 128 is convex on the surface 31a of the substrate 31 as shown in FIG. A wiring pattern 126 is formed.
Also, for example, as shown in FIG. 20A, when the surface 52 of the ink 52b is concave on the printing plate 25 and the surface 116 is concave, the surface 132 is concave on the surface 31a of the substrate 31 as shown in FIG. A simple wiring pattern 130 is formed.
The ink 52b having a concave surface 116 is shown in FIGS. 20A and 20B, but the wiring pattern 134 having the concave portion 136 on the surface 31a side of the substrate 31 shown in FIG. Not formed.

In the printing apparatus 10, the plate surface observation unit 26 and the determination unit 16 d are provided, and the plate surface observation unit 26 images the plate surface 25 a of the printing plate 25 to which ink is applied to obtain plate surface imaging data, and the adjustment unit 16 determines It is possible to determine whether or not the ink application is appropriate in the part 16d. According to the determination result in the determination unit 16d of the adjustment unit 16, by performing the ink application method and the restoration of the printing plate from the next time onward, it is not a direct print result, but an inspection equivalent to the print result on the actual substrate Thus, the reliability of inspection can be improved and the printing accuracy can be improved. Moreover, the substrate 31 is not wasted for printing confirmation. Furthermore, since there is no need for a complicated configuration such as an inspection roll, the apparatus cost can be reduced.
In addition, doctoring is not required, and the soiling of the plate surface 25a of the printing plate 25 accompanying the doctoring can be prevented, and the durability of the printing plate 25 can be improved.

Next, the printing method of this embodiment will be described using the printing apparatus 10.
FIG. 21 is a schematic diagram for explaining the printing method according to the embodiment of the present invention.
As described above, the plate cylinder 24 is rotated a plurality of times, and ink is applied to the pattern area at each rotation. In FIG. 21, the distance indicates the amount of rotation of the plate cylinder 24, and the distance 0 indicates the initial position of the printing plate 25.
In FIG. 21, reference numeral 100 indicates ink ejection timing, reference numeral 102 indicates a section for drying ink, and reference numeral 104 indicates a section for transferring to the substrate 31. Reference numeral 106 denotes a printing start position of the printing plate 25 when printing is performed a plurality of times.

In the printing apparatus 10, a specific pattern is printed on the substrate 31 based on the pattern data of the pattern to be printed. The position information of the alignment marks A to D is acquired by the alignment camera 42, the mounting position information of the printing plate 25 is acquired, and the inclination of the printing plate 25 is obtained. However, when the inclination of the printing plate 25 is within the allowable range, the pattern is printed without correcting the inclination. In this case, the reading unit 47 acquires the position information of the mark 90 in the alignment areas M _{1 to} M ₃ and the ink landing position information, that is, the position information of the dot 92, and the position of the mark 90 and the position of the dot 92 are acquired. Difference data is calculated, and the ink ejection timing from the inkjet head 40 is adjusted based on the difference data. In this state, ink is ejected onto the printing plate 25 with a predetermined ejection waveform, and inking is performed.
On the other hand, when the inclination of the printing plate 25 is out of the allowable range, the inclination is corrected and the pattern is printed. By correcting the inclination of the printing plate 25 in this way, the printing accuracy can be improved even when the mounting accuracy of the printing plate 25 is low.

In the example shown in FIG. 21, the plate cylinder 24 is rotated four times, and ink is ejected at each rotation. For each ink droplet, information on the plate surface 25a of the printing plate 25 is acquired by the plate surface observation unit 26, determined by the determination unit 16d of the adjustment unit 16, and based on the determination result, the control unit 18 determines the ink level. The ejection amount and ejection density are adjusted, and the next ink droplet is ejected. In this case, when there is a deficiency in the concave portion of the printing plate 25, the amount of ink ejected around the deficient portion is increased, and the formed dots are enlarged. In addition to this, the droplet ejection density is increased by increasing the number of droplets ejected in advance.
On the other hand, if a large dot is formed in the concave portion of the printing plate 25 when the previous ink is ejected, the amount of ink ejected is reduced and the formed dot is reduced. In addition to this, the droplet ejection density is lowered by reducing the number of droplets ejected in advance.
Moreover, when the inkjet head 40 has a redundant nozzle, a redundant nozzle can also be used.

For example, in the case of 2400 dpi pattern data, ink is applied (inked) to the pattern area by scanning four times with a 1200 dpi pattern in both the X and Y directions and four times scanning with a 600 dpi and 2400 dpi pattern in the Y direction. Can be completed.
For example, in the case of 1200 dpi in both the X direction and the Y direction, the distance between adjacent pixels (minimum value) of one nozzle is 21.2 μm, and the discharge frequency requirement is low, but the number of nozzles is twice that in the X direction compared with 600 dpi. Necessary. The distance (minimum value) between adjacent pixels in the X direction is 21.2 μm, and there is a concern about the influence of X direction landing interference.
On the other hand, in the case of 600 dpi in the X direction and 2400 dpi in the Y direction, the number of nozzles is ½ compared to the above-mentioned X direction of 1200 dpi, and the distance (minimum value) between adjacent pixels in the X direction is 42.3 μm. Although the influence is reduced, the distance (minimum value) between adjacent pixels in the Y direction is 10.6 μm, and twice the high-frequency ejection is required in both the X direction and the Y direction compared to the case of 1200 dpi.

Next, the printing method of the printing apparatus 10 of this embodiment will be described more specifically.
FIG. 22 is a flowchart illustrating the printing method according to the embodiment of the present invention.
First, ink is supplied to the ink tank (step S10). In step S10, first, ink is fed from the ink tank to the sub tank. Then, ink is supplied from the sub tank to the inkjet head 40.
When supplying ink, the cleaning liquid is replaced with ink. Ink can be supplied after the cleaning liquid is discharged from the inkjet head 40 with nitrogen gas, but it is easy to entrain the nitrogen gas. For this reason, it is preferable to replace the supply of ink from the cleaning liquid.

In a state where the cleaning liquid is supplied to the ink jet head 40, the ejection is confirmed. When the result is not good at the time of the discharge confirmation, the discharge recovery is performed using the maintenance unit 36. If it cannot be recovered, the inkjet head 40 is replaced as necessary.
When replacing the cleaning liquid with ink, for example, the cleaning liquid in the sub tank 50 is reduced to the lower limit. Next, ink is put into the sub tank 50, and the cleaning liquid in the inkjet head 40 is pushed away with the ink. Next, the ink in the sub tank 50 is reduced to the lower limit. The cleaning liquid in the inkjet head 40 is pushed away with ink, and the ink in the sub tank 50 is repeatedly reduced to the lower limit to replace the cleaning liquid with ink.

Next, alignment is performed (step S12).
In this case, alignment between the position of the inkjet head 40 and the plate position is performed. First, the alignment marks A to C are read by the alignment camera 42 and their positions are detected.
Next, the absolute distance in the X direction is obtained. In this case, for example, it is calculated from the position of the carriage 46 (linear scale read value) when the alignment marks A and B are at the same position in the X direction of the visual field of the alignment camera 42.
Next, the absolute distance in the Y direction is obtained. In this case, the alignment marks A and C are calculated from the rotational position information of the plate cylinder 24 output from the measurement unit 16a when the alignment marks A and C are at the same position in the Y direction of the visual field of the alignment camera 42. In the Y direction, alignment is adjusted not by distance but by angle.

Next, the relative inclination between the inkjet head 40 and the printing plate 25 is obtained. In this case, the inclination angle θ is obtained. The displacement is measured not only in the X direction position of the alignment marks A and B but also in the Y direction. The deviation in the Y direction is calculated from the rotational position information of the plate cylinder 24 output from the measuring unit 16a when the Y direction of the visual field of the alignment camera 42 is also the same, and the inclination is calculated from the distance in the X direction and the deviation in the Y direction. The angle θ is calculated. Alternatively, the tilt angle θ can be calculated from the deviation in the Y direction within the camera field of view.
Further, the position information of the printing plate 25 attached to the plate cylinder 24 is obtained from the position information of the alignment marks A to C. That is, information on how the printing plate 25 is attached to the plate cylinder 24 is obtained. Then, the inclination angle α of the printing plate 25 is obtained. For example, the angle α can be calculated from the distance in the X direction and the deviation in the Y direction.

  The distance in the X direction, the angle in the Y direction, and the tilt angle θ obtained as described above are stored in the storage unit 14. In the control unit 18, the distance based on the X direction, the angle in the Y direction, the inclination angle θ, and the pattern data to be printed stored in the storage unit 14, enlargement / reduction processing in the X direction and Y direction, and the pattern based on the inclination angle θ Rotate the data to correct the pattern data. The correction of the inclination of the printing plate 25 is performed on the corrected pattern data as necessary.

Next, the ink ejection timing is confirmed (step S14).
In step S <b> 14, ink is ejected from the inkjet head 40 to the marks 90 in the alignment areas M _{1 to} M ₃ to obtain dots 92. Next, the position information of the mark 90 and the position information of the plurality of dots 92 of the ink ejected with respect to the mark 90, that is, the position information of the ink landing position are acquired by the reading unit 47. Then, the difference between the position of the mark 90 and the position of the dot 92 in the rotation direction of the plate cylinder 24 is obtained, and data on the difference between the position of the mark 90 and the position of the dot 92 is obtained. Note that step S14 for confirming the discharge timing corresponds to the obtaining step.

Next, the adjustment unit 16b adjusts the ink ejection timing based on the difference data between the position of the mark 90 and the position of the dot 92 in the rotation direction of the plate cylinder 24 (step S16).
In step S <b> 16, the adjustment unit 16 b obtains the ink ejection timing with the smallest error with respect to the inking length described above, and generates corrected ejection timing data in which the ink ejection timing is adjusted. For example, the technique disclosed in Japanese Patent Laid-Open No. 2005-246123 can be used to adjust the discharge timing. Note that step S16 for adjusting the discharge timing corresponds to the adjustment step.

Next, discharge confirmation of the inkjet head 40 is performed (step S18).
In this case, it is performed by evaluating the printed matter of the test pattern or by observing the discharge.
The printed matter of the test pattern print is evaluated by visual inspection of the printed substrate or by a scanner. Further, it is also possible to carry out by observing the ink on the printing plate 25 with the alignment camera 42 without discharging only the printing plate 25 and discharging.
The printing plate 25 is provided with the discharge confirmation area T as described above, and ink is ejected onto it. An ejection confirmation area T may be provided in the plate cylinder 24 and ink may be ejected thereto.
After the evaluation, the ink in the discharge confirmation area T is removed by the cleaning unit 34 or transferred to the substrate 31 and removed.

If the result of the discharge confirmation is out of the predetermined range, the recovery operation is performed by the maintenance unit 36, or the discharge waveform is optimized by the discharge control unit 43.
Along with the ejection confirmation, information on the landing position of the ink that has been deposited on the printing plate 25 is acquired using the alignment camera 42. In the adjustment unit 16, the deviation of the landing position is determined, and when the X direction, the Y direction, and the inclination angle θ are out of the predetermined ranges, the enlargement / reduction, rotation, etc. of the correction pattern data are adjusted again.

Next, inking into the printing plate is performed (step S20).
Pattern data or correction pattern data is sent to the ejection control unit 43, the plate cylinder 24 is rotated, and ink is ejected from the inkjet head 40 to the printing plate 25 with a predetermined ejection waveform at the adjusted ink ejection timing. , Inking. For example, the plate cylinder 24 is rotated four times, that is, scanned four times to apply ink to the pattern area. In this case, spit is performed for each scan. The spit is performed in a spit area G (not shown) for the spit provided on the spit area G of the printing plate 25 or the plate cylinder 24.
The spit timing may be after each printing plate even after the pattern is formed in the printing area. Further, purge, wipe, and spit may be performed by the maintenance unit 36 for every certain number of printed sheets, such as every 100 printing plates, and further ejection confirmation may be performed. Note that step S20 for inking the printing plate corresponds to an ejection process.

Next, the inked printing plate 25 is transferred to the substrate 31 (step S22).
First, the substrate 31 is placed on the stage 30 and waits at the start position Ps. Then, the substrate 31 is aligned for alignment of the pattern of the printing plate 25.
Next, the stage 30 is moved in the transport direction V, and the substrate 31 is disposed at the printing position Pp below the plate cylinder 24. Then, the plate cylinder 24 is rotated to bring the printing plate 25 and the surface 31 a of the substrate 31 into contact with each other, thereby transferring the ink of the printing plate 25 to the substrate 31. After the transfer, the stage 30 is moved in the transport direction V, and the printing plate 25 is moved from the printing position Pp below the plate cylinder 24 to the end position Pe. Thereafter, the printing plate 25 on which the pattern is formed is moved from the stage 30 and taken out of the casing 20.

  The present invention is basically configured as described above. Although the printing apparatus and the printing method of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various improvements or modifications may be made without departing from the spirit of the present invention. Of course.

DESCRIPTION OF SYMBOLS 10 Printing apparatus 12 Printing apparatus main body 14 Memory | storage part 16 Adjustment unit 16a Measuring part 18 Control part 20 Casing 22 Image recording part 24 Plate cylinder 25 Printing plate 26 Plate surface observation part 30 Stage 31 Substrate 32 Drying part 34 Cleaning part 36 Maintenance part 37 Measurement Container 40 Inkjet head 42 Alignment camera 43 Discharge control unit 44 Laser displacement meter 46 Carriage 47 Reading unit 48 Linear motor 49 Rotating unit 50, 58 Sub tank 76 Discharge observation unit 78 Nozzle observation unit 90 Mark 92 dots A to D Alignment mark G Spit area M _{1, M} 2, _{M 3} alignment area T discharge check area _{G 11, G 12, G 21} , G 22, G 31, G 32 printing area 94a, 94b, 94c, 94d, 94e, marks 96a, 96 , 96c, 96d, 96e, 140a, 140b, 140c mark

Claims (10)

A printing apparatus that, after ejecting ink in a predetermined pattern on a printing plate surface, transfers the ink ejected in the pattern onto a substrate,
A mark serving as a reference for the ink landing position is formed on the plate surface of the printing plate,
The printing plate is provided, and a rotatable plate cylinder;
An image recording unit that ejects the ink from a plurality of nozzles in an inkjet manner onto the plate surface of the printing plate in the predetermined pattern;
The position information of the plurality of droplet landing positions of the ink ejected from the image recording unit with respect to the mark position and the mark is acquired, and data on the difference between the mark position and the ink droplet deposition position is obtained. A reading unit;
A printing apparatus comprising: an adjustment unit that adjusts the ejection timing of the ink in the image recording unit based on data of a difference between the mark position obtained by the reading unit and the ink landing position.   The printing apparatus according to claim 1, wherein the marks are provided at least at three positions along a direction parallel to a rotation axis of the plate cylinder.   The mark is formed in a mark forming region, the mark is formed of a convex portion, the mark forming region is formed of a concave portion, the convex portion is an ink repellent portion, and the concave portion is a parent ink portion. Item 3. The printing apparatus according to Item 1 or 2.   The printing apparatus according to claim 1, wherein the image recording unit deposits the ink on the mark.   5. The difference data between the mark position and the ink landing position is difference data between an average position of the ink landing positions and the mark position. 6. The printing apparatus as described. A printing method in which ink is ejected in a predetermined pattern onto a plate surface of a printing plate provided in a plate cylinder, and then the ink ejected in the pattern is transferred to a substrate.
A mark serving as a reference for the ink landing position is formed on the plate surface of the printing plate,
Acquire position information of the mark position and a plurality of droplet deposition positions of ink ejected to the mark, and obtain data of a difference between the mark position and the ink droplet deposition position in the rotation direction of the plate cylinder Obtaining process;
An adjustment step of adjusting the ejection timing of the ink in the image recording unit based on data of the difference between the mark position and the ink landing position;
And a discharge step of discharging ink onto the plate surface of the printing plate at the discharge timing adjusted in the adjustment step.   The printing method according to claim 6, wherein the marks are provided at least at three positions along a direction parallel to a rotation axis of the plate cylinder.   The mark is formed in a mark forming region, the mark is formed of a convex portion, the mark forming region is formed of a concave portion, the convex portion is an ink repellent portion, and the concave portion is a parent ink portion. Item 8. The printing apparatus according to Item 6 or 7.   The printing method according to claim 6, wherein the ink is deposited on the mark.   The data of the difference between the mark position and the ink landing position is data of a difference between an average position of the plurality of ink landing positions and the mark position. The printing method described.

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