JP2002273847A - Method and equipment for plate making - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and equipment for making a plate of a plate material being capable of meeting digital image data and printing a large number of prints of a clear image inexpensively and at a high speed. SOLUTION: The equipment for plate making has an image forming means which forms an image directly on the plate material by an ink jet image drawing device 2 which makes oil-based ink discharged from a discharge head 22 on the basis of signals of image data and with an electrostatic field used, and an image fixing means which fixes the image formed by the image forming means, so as to obtain a printing plate. The equipment is provided with a stirring means 27 for re-dispersing the agglomerate and the sediment of the oil- based ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate making method and a plate making apparatus for performing digital plate making, and more particularly, to a plate making method and a plate making apparatus using oil-based ink and having good image quality and printing quality.

[0002]

2. Description of the Related Art In lithographic printing, printing ink receiving and printing ink repelling areas are provided on the surface of a printing plate corresponding to an image original, and printing is performed by adhering printing ink to the ink receiving areas. . Usually, hydrophilic and lipophilic (ink-receptive) areas are formed imagewise on the surface of the printing plate, and the hydrophilic areas are made ink-repellent by using a fountain solution.

In recording an image on a printing original plate (plate making), an image original is first output in analog or digital form to a silver halide photographic film, through which a diazo resin or a photopolymerizable photopolymer photosensitive material (printing original plate) is passed. Is generally performed by exposing the non-image portion to elution and removal mainly using an alkaline solution.

In recent years, in the lithographic printing method, due to the recent improvement of digital drawing technology and the demand for more efficient processes,
Many systems for directly drawing digital image information on a printing plate have been proposed. This is CTP (Computer
to Plate) or DDPP (Digital Direct Printi)
ng Plate). As a plate making method, for example, there is a system for recording an image in an optical mode or a thermal mode using a laser, and a part of the system has been put into practical use.

However, in this plate making method, in both the light mode and the heat mode, plate making is generally performed by treating with an alkaline developer after laser recording to dissolve and remove non-image portions.
Alkaline waste liquid is discharged, which is not preferable for environmental protection.

On the other hand, since the above-described method using a laser is expensive and large, a system using an inkjet method, which is an inexpensive and compact drawing apparatus, has been attempted.

Japanese Patent Application Laid-Open No. 64-27953 discloses a method of performing plate making by drawing with an ink jet using a lipophilic wax ink on a hydrophilic plate material. In this method, the image is formed with wax, so that the mechanical strength of the image portion is weak, and the adhesion to the hydrophilic surface of the printing plate is insufficient, so that the printing durability is low.

In the case of drawing by ink jet, particles in the ink are aggregated due to stationary liquid flow or the like, causing clogging of a pipe or clogging of a head.
There is a problem that ink ejection becomes unstable, image quality is deteriorated, and ejection is stopped. Further, when the particle diameter is large, spontaneous sedimentation may occur when the ink is in a stationary state, so that ejection at a uniform particle density becomes impossible, and a normal drawn image cannot be obtained.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a planographic printing plate capable of obtaining a large number of clear and high-quality printed materials by an inexpensive and simple method. It is an object of the present invention to provide a digital plate making method and a plate making apparatus which does not require a developing process for enabling a printing plate to be prepared.

[0010]

The above object is achieved by the following (1).
To (23) according to the present invention. (1) Plate making, in which an image is formed directly on a plate material by an electrostatic ink jet method in which an oil-based ink is ejected using an electrostatic field based on a signal of image data, and the image is fixed to form a printing plate The method according to claim 1, wherein the agglomerated oil-based ink particles and / or agglomerates caused by at least a stationary flow of the ink.
Alternatively, a plate making method characterized by re-dispersing the sediment. (2) The oil-based ink has a specific electric resistance of 10 ⁹ Ωc.
The plate making method according to (1), wherein solid and hydrophobic resin particles are dispersed at least at room temperature in a non-aqueous solvent having a dielectric constant of at least m and a dielectric constant of at most 3.5. (3) An image forming means for forming an image directly on a plate material by an ink jet drawing apparatus for discharging an oil-based ink from a discharge head using an electrostatic field based on a signal of image data, and an image forming means formed by the image forming means. A plate making apparatus having an image fixing means for fixing an image to obtain a printing plate, comprising a means for re-dispersing at least aggregates and / or sediments of the oil-based ink particles generated by, for example, stationary ink flow. A plate making apparatus characterized by the above-mentioned. According to the plate making apparatus, since the means for re-dispersing aggregates and / or sediments of oil-based ink particles is provided, the ink can be returned to a well-dispersed state. (4) The plate making apparatus according to (3), wherein a means for redispersing at least aggregates and / or sediments of the ink particles is provided immediately before the ink discharge section of the discharge head. According to the plate making apparatus, since the re-dispersion means is particularly arranged immediately before the ejection head, the ink in a good dispersion state immediately after the re-dispersion can be supplied to the ejection head. (5) The plate making apparatus according to (3) or (4), wherein the means for redispersing the aggregates and / or sediments of the ink particles operates at least before and / or simultaneously with the flow of the ink. According to the plate making apparatus, by operating the re-dispersion means particularly before the ink flow, a good re-dispersed ink flow can be obtained. (6) The means for redispersing the aggregates and / or sediments of the ink particles is performed by an operation including any one of stirring, dispersion, mixing, and jetting. (3) to (5) A plate-making apparatus according to any one of the above. (7) The plate making apparatus according to any one of (3) to (6), wherein the stirring, dispersing, mixing, and jetting actions are applied alone, in a plurality, or in multiples. According to the plate making apparatus, the re-dispersion means is constituted by a combination of the stirring, the dispersion, the mixing, and the jet action, whereby the re-dispersion can be performed more favorably. (8) The plate making apparatus according to any one of (3) to (7), wherein the stirring, dispersing, mixing, and jetting actions are applied as needed, periodically or continuously. According to the plate making apparatus, a good ink state can be maintained by causing the stirring, dispersion, mixing, and jetting functions to function as needed, periodically or continuously. (9) The plate making apparatus according to any one of (3) to (8), wherein the means for redispersing the aggregates and / or sediments of the ink particles is replaceable as a cartridge. According to the plate making apparatus, maintenance can be facilitated by making the re-dispersion means replaceable as a cartridge. (10) The oil-based ink has a specific electric resistance of 10 ⁹ Ω.
The plate making apparatus according to any one of (3) to (9), wherein solid and hydrophobic resin particles are dispersed at least at room temperature in a non-aqueous solvent having a dielectric constant of 3.5 cm or more and a dielectric constant of 3.5 or less. (11) The image fixing means has a heating means using a heat roller and / or an infrared lamp, a halogen lamp or a xenon flash lamp (3) to (1).
0) A plate-making apparatus according to any one of the above. (12) The heating means is arranged and / or arranged so as to gradually increase the temperature of the plate material when fixing the image.
Alternatively, the plate making apparatus according to (11), which is controlled. (13) The plate making apparatus according to any one of (3) to (12), wherein, at the time of drawing on the plate material, main scanning is performed by rotating a drum on which the plate material is mounted. (14) The plate-making apparatus according to (13), wherein the ejection head is a single-channel head or a multi-channel head, and performs sub-scanning by moving the ejection head in a direction parallel to the axis of the drum. (15) The plate making apparatus according to any one of (3) to (12), wherein at the time of drawing on the plate material, sub-scanning is performed by nipping and moving the plate material by at least a pair of capstan rollers. (16) The plate making apparatus according to (15), wherein the discharge head is a single-channel head or a multi-channel head, and performs main scanning by moving the discharge head in a direction orthogonal to a direction in which the plate material travels. (17) The discharge head is a full line head having a length substantially equal to the width of the plate material (13) or (1).
The plate making apparatus according to 5). (18) The plate making apparatus according to any one of (3) to (17), wherein the inkjet drawing apparatus has an ink supply unit that supplies the oil-based ink to the ejection head. (19) The plate making apparatus according to (18), further including an ink recovery unit configured to recover the oil-based ink from the discharge head, and performing ink circulation. (20) The plate making apparatus according to any one of (3) to (19), further including dust removing means for removing dust existing on the surface of the plate material before and / or during drawing on the plate material. (21) The ink jet drawing apparatus has an ink temperature management means for managing a temperature of the oil-based ink in an ink tank storing the oil-based ink. (3) to (2)
0) A plate-making apparatus according to any one of the above. (22) The plate making apparatus according to any one of (3) to (21), wherein the inkjet drawing apparatus has an ink density control unit that controls the density of the oil-based ink. (23) The plate making apparatus according to any one of (3) to (22), further including a cleaning unit configured to clean the ejection head.

[0011]

Embodiments of the present invention will be described below in detail. The present invention relates to a printing plate (printing plate)
An image is formed by an inkjet method in which oil-based ink is discharged by an electrostatic field.

In the present invention, the size of the ejected ink droplet is determined by the size of the tip of the ejection electrode or the condition for forming the electric field. Therefore, by using a small ejection electrode or adjusting the electric field forming conditions, a small ink droplet can be obtained without reducing the ejection nozzle diameter or the ejection slit width. Therefore, the present invention provides a plate making method and a plate making apparatus capable of controlling a minute image without causing a problem of ink clogging of a head and obtaining a printing plate capable of printing a large number of clear images.

An example of the configuration of a plate making apparatus used to carry out the plate making method of the present invention will be described below. 1 and 2 are general configuration diagrams of the plate making apparatus. FIG. 3 shows a control unit of the plate making apparatus;
3 is a schematic configuration example of a drawing unit including an ink supply unit and a head detachment mechanism. FIGS. 4 to 10 are for explaining the ink jet drawing apparatus provided in the plate making apparatus shown in FIGS.

First, the plate making process according to the present invention will be described with reference to an overall configuration diagram of a plate making apparatus having a structure in which a plate material is mounted on a drawing drum 11 as shown in FIG. However, the present invention is not limited to the following configuration examples.

The drum 11 is usually made of metal such as aluminum, stainless steel or iron, plastic, glass or the like. Particularly, in the case of a metal drum, its surface is often subjected to, for example, anodizing or chrome plating in order to enhance abrasion resistance and rust prevention. The drum 11 may have a heat insulating material on its surface as described later. Further, it is preferable that the drum 11 has a ground function as a counter electrode of the discharge head electrode in the electrostatic field discharge. On the other hand, when the insulating property of the plate base is high, it is preferable to provide a conductive layer on the base. In this case, it is preferable to provide a means for grounding the conductive layer. Further, even when a heat insulating material is provided on the drum 11 as described above, drawing is facilitated by providing a means for grounding the plate material. In this case, a known means such as a brush, a leaf spring, or a roller having conductivity can be used.

Further, the plate making apparatus 1 has an ink jet drawing apparatus 2, which can
In accordance with the image data sent from the printer, oil-based ink is discharged onto the plate material 9 mounted on the drum 11 to form an image.

Further, the plate making apparatus 1 has a fixing device 5 for strengthening the oil-based ink image drawn on the plate material 9. If necessary, a plate surface desensitizing device 6 used for the purpose of enhancing the hydrophilicity of the surface of the plate material 9 may be provided. In addition, the plate making device 1 may be configured to print the plate material 9 before and / or during drawing on the plate material 9.
It has dust removing means 10 for removing dust present on the surface.
As a result, it is possible to effectively prevent the ink from adhering to the plate material 9 by transmitting dust between the head and the plate material during plate making,
Good plate making is performed. As the dust removing means 10, in addition to a known non-contact method such as suction removal, blowing removal, and electrostatic removal, a contact method using a brush, a roller, or the like can be used. In the present invention, any of air suction and air blowing is preferable. Or a combination thereof.

Further, an automatic plate feeding device 7 for automatically supplying the plate material 9 onto the drum 11 and an automatic plate discharging device 8 for automatically removing the plate material 9 after drawing from the drum 11 are provided. Good. The use of the automatic plate feeding device 7 and the automatic plate discharging device 8 makes the plate making operation easier and shortens the plate making time, so that the effects of the present invention can be further enhanced.

Referring to FIG. 1 and a part of FIG.
The process of producing a printing plate by the above will be described below.

First, the plate material 9 is mounted on the drum 11 using the automatic plate feeding device 7. At this time, the plate material 9 is closely fixed on the drum 11 by a mechanical method using a known plate head / butt holding device, an air suction device, or the like, or the like, whereby the plate bottom is fluttered and drawing is performed. It is possible to prevent the ink jet drawing apparatus 2 from being damaged by contact with the ink jet drawing apparatus 2. Means for adhering the plate material 9 to the drum 11 only around the drawing position of the ink jet drawing device 2 are provided, and at least at the time of drawing, the plate material 9 is prevented from coming into contact with the ink jet drawing device 2 by acting. You can also. Specifically, for example, there is a method of disposing a pressing roller upstream and downstream of the drawing position on the drum 11.
Further, when the drawing is not performed, it is desirable to keep the head away from the plate material, which can effectively prevent the ink jet drawing apparatus 2 from suffering a problem such as contact damage.

The image data arithmetic control unit 21 receives image data from an image scanner, a magnetic disk device, an image data transmission device, etc., performs color separation as necessary, and applies an appropriate pixel to the separated data. Divide calculation into number and gradation number. Furthermore, in order to draw an oil-based ink image in a halftone dot using the ink jet discharge head 22 (see FIG. 3 and described in detail later) included in the ink jet drawing apparatus 2, calculation of a dot area ratio is also performed. Also, as described below,
The image data calculation control unit 21 controls the movement of the inkjet discharge head 22 and the discharge timing of the oil-based ink, and also controls the operation timing of the drum 11 and the like as necessary. The calculation data input to the image data calculation control unit 21 is temporarily stored in a buffer. The image data calculation control unit 21 rotates the drum 11 and
Is brought closer to the position close to the drum 11 by the head separation / contact device 31. Discharge head 22 and plate 9 on drum 11
The distance from the surface is controlled to a predetermined distance during drawing by mechanical distance control such as an abutment roller, or control of a head separation / contact device by a signal from an optical distance detector. By such distance control, good plate making can be performed without the dot diameter becoming non-uniform due to the floating of the plate material or the dot diameter not changing even when vibration is applied to the plate making machine.

As the ejection head 22, a single-channel head, a multi-channel head, or a full-line head can be used, and the main scanning is performed by rotating the drum 11. In the case of a multi-channel head having a plurality of discharge units or a full line head, the arrangement direction of the discharge units is set in the axial direction of the drum 11. Further, in the case of a single channel head or a multi-channel head, the discharge head 22 is moved by the image data calculation control unit 21 in a direction parallel to the axis of the drum 11 for each rotation of the drum 11, and the discharge position obtained by the above calculation is obtained. Further, the oil-based ink is discharged onto the plate material 9 mounted on the drum 11 at a dot area ratio. As a result, a halftone image corresponding to the density of the print document is drawn on the plate material 9 with the oil-based ink. This operation continues until an oil-based ink image for one color of the printing original is formed on the plate material 9 and the printing plate is completed. On the other hand, the ejection head 2
When the full line head 2 has the same length as the width of the drum 11, the drum 11 makes one rotation to form an oil-based ink image for one color of the printing original on the plate material 9 to complete the printing plate. . By performing the main scanning by rotating the drum 11 in this manner, the positional accuracy in the main scanning direction can be improved, and high-speed drawing can be performed.

Next, in order to protect the ejection head 22, the ejection head 22 is retracted away from a position close to the drum 11. This separation / contact means operates so that the ejection head is separated from the drum by at least 500 μm except during drawing. The separation / contact operation may be performed by a slide type, or the ejection head 22 may be fixed by an arm fixed to a certain axis, and the arm may be moved around the axis to move like a pendulum. By retracting the ejection head 22 during non-drawing in this way, the ejection head 22 can be protected from physical damage or contamination, and a long life can be achieved.

Further, the formed oil-based ink image is reinforced by the fixing device 5. As a means of fixing ink,
Known means such as heat fixing and solvent fixing can be used. In the heat fixing, irradiation with an infrared lamp, a halogen lamp, a xenon flash lamp, hot air fixing using a heater, and heat roll fixing are generally used. In this case, the drum 9 is heated in order to enhance the fixing property.
Is heated in advance, drawing is performed while applying hot air, the drum 11 is coated with a heat insulating material, and the drum 11 is fixed at the time of fixing.
It is effective to take measures such as separating the plate material 9 from the substrate and heating only the plate material 9 alone or in combination.
Flash fixing using a xenon lamp or the like is known as a method for fixing electrophotographic toner, and has an advantage that fixing can be performed in a short time. Also, when using paper plates,
The water inside the plate evaporates rapidly due to the rapid temperature rise,
Since a phenomenon called blister, in which irregularities occur on the plate material surface, occurs, the drum 1 is heated so that the temperature of the paper plate material gradually increases.
It is preferable to gradually increase the power supply to the heat source while rotating 1, or to change the rotation speed from high speed to low speed with constant power supply. Alternatively, the paper plate material may be gradually heated by disposing a plurality of fixing devices in the rotation direction of the drum 11 and changing the distance to the plate material 9 and / or the supplied power.

In solvent fixing, a solvent capable of dissolving the resin component in the ink, such as methanol or ethyl acetate, is sprayed or exposed to vapor, and excess solvent vapor is recovered. In addition, at least in the process from the formation of the oil-based ink image by the ejection head 22 to the fixing by the fixing device 5, it is desirable that nothing is kept in contact with the image on the plate material 9.

A configuration example of a plate making apparatus for performing sub-scanning by moving the plate material 9 will be described with reference to FIG. However, the present invention is not limited to the following configuration examples.

The plate material 9 includes two pairs of capstan rollers 1.
2, and the image is drawn by the ink jet drawing apparatus 2 using the data divided and calculated by the image data calculation control unit 21 into an appropriate number of pixels and gradations. It is preferable that a grounding means 13 is provided at a portion where drawing is performed by the inkjet drawing device 2 so as to be a counter electrode of the discharge head electrode in electrostatic field discharge, thereby facilitating drawing. On the other hand, when the insulating property of the base of the plate material 9 is high, it is preferable to provide a conductive layer on the base. It is desirable to take the ground.

FIG. 2 shows an apparatus using a sheet plate material, but a roll plate material is also suitably used. In this case, it is desirable to provide a sheet cutter upstream of the automatic plate discharging device. Further, the plate making apparatus has the ink jet drawing apparatus 2, and the
An oil-based ink is discharged onto the plate material 9 to form an image in accordance with the image data sent from the printer.

The plate making device 1 has a fixing device 5 for strengthening the oil-based ink image drawn on the plate material 9. A plate surface desensitizing device 6 used as needed for the purpose of enhancing the hydrophilicity of the surface of the plate material 9 may be provided. In addition, the plate making apparatus 1 includes dust removing means 10 for removing dust existing on the plate material surface before and / or during drawing on the plate material 9. Accordingly, it is possible to effectively prevent ink from adhering to the plate material by transmitting dust between the discharge head and the plate material during plate making, and perform good plate making. As the dust removing means 10, in addition to a known non-contact method such as suction removal, blowing removal, and electrostatic removal,
A contact method using a brush, a roller, or the like can be used, and in the present invention, it is preferable to use either air suction or air blowing, or a combination thereof.

Further, it is preferable to provide an automatic plate feeding device 7 for automatically supplying the plate material 9 and an automatic plate discharging device 8 for automatically removing the plate material 9 after drawing. The use of the automatic plate feeding device 7 and the automatic plate discharging device 8 makes the plate making operation easier and shortens the plate making time, so that the effects of the present invention can be further enhanced.

Referring to FIG. 2 and partly in FIG.
Will be described in more detail below.

First, the plate material 9 is transported by using the automatic plate feeding device 7 and the cap stun roller 12. At this time, if necessary, by providing a plate material guide means (not shown) or the like, it is possible to prevent the plate head / tail of the plate material from fluttering and coming into contact with the ink jet drawing apparatus 2 and being damaged. In addition, means for preventing the plate material 9 from being loosened only around the drawing position of the ink jet drawing device 2 is provided, and at least at the time of drawing, the plate material 9 is prevented from contacting the ink jet drawing device 2 by acting. You can also. Specifically, for example, there is a method of disposing a pressing roller upstream and downstream of the drawing position. Further, when the drawing is not performed, it is desirable to keep the ejection head away from the plate material 9, which can effectively prevent the ink jet drawing apparatus 2 from causing troubles such as contact damage.

Image data from a magnetic disk device or the like
The image data calculation control unit 21 is provided with the image data calculation control unit 21 and calculates the ejection position of the oil-based ink and the halftone dot area ratio at that position in accordance with the input image data. These operation data are temporarily stored in the buffer. The image data calculation control unit 21 controls the movement of the ejection head 22, the ejection timing control of the oil-based ink, and the operation timing control of the capstan roller. Move closer to the close position. The distance between the ejection head 22 and the surface of the printing plate 9 was maintained at a predetermined distance during drawing by mechanical distance control such as a contact roller, or control of a head separation device by a signal from an optical distance detector. It is. By such distance control, good plate making can be performed without the dot diameter becoming non-uniform due to the floating of the plate material or the dot diameter not changing even when vibration is applied to the plate making machine.

As the ejection head 22, a single-channel head, a multi-channel head, or a full-line head can be used. In the case of a multi-channel head having a plurality of ejection portions, the arrangement direction of the ejection portions is set substantially parallel to the traveling direction of the printing plate. Further, in the case of a single channel head or a multi-channel head, the ejection head 22 is moved by the image data calculation control unit 21 in the direction orthogonal to the traveling direction of the plate material 9 every time the plate material moves, and the ejection obtained by the above calculation is performed. Plate material 9 with oil-based ink at position and dot area ratio
To be discharged. As a result, a halftone image corresponding to the density of the print document is drawn on the plate material 9 with the oil-based ink. This operation continues until an oil-based ink image for one color of the printing original is formed on the plate material 9 and the printing plate is completed. On the other hand, the ejection head 22
Is a full line head having substantially the same length as the width of the plate 9, the arrangement direction of the ejection units is set to a direction substantially orthogonal to the running direction of the plate, and the plate 9 passes through the drawing unit. By doing so, an oil-based ink image for one color of the printing original is formed on the plate material 9, and a printing plate is completed.

In order to protect the discharge head 22, it is preferable that the discharge head 22 is retracted away from a position close to the plate material 9. This separation / contact means operates so that the ejection head is separated from the plate material 9 by at least 500 μm except during drawing. The detachment operation may be a slide type, or the ejection head may be fixed by an arm fixed to a certain axis, and the arm may be moved around the axis to move like a pendulum. By retreating the ejection head during non-drawing as described above, the ejection head can be protected from physical damage or contamination, and a long life can be achieved.

Further, the formed oil-based ink image is reinforced by the fixing device 5. As a means of fixing ink,
Known means such as heat fixing and solvent fixing can be used. In the heat fixing, irradiation with an infrared lamp, a halogen lamp, a xenon flash lamp, hot air fixing using a heater, and heat roll fixing are generally used. Flash fixing using a xenon lamp or the like is known as a method for fixing electrophotographic toner, and has an advantage that fixing can be performed in a short time. Also, when using a paper plate material, a phenomenon called blister occurs, in which the water inside the plate material evaporates rapidly due to a rapid temperature rise, and irregularities are generated on the plate material surface.
It is preferable to dispose a plurality of fixing devices and change the power supply and / or the distance of the fixing device to the plate material 9 so as to gradually increase the temperature of the paper plate material in order to prevent blisters of the plate material 9. .

In solvent fixing, a solvent capable of dissolving the resin component in the ink, such as methanol or ethyl acetate, is sprayed or exposed to steam, and excess solvent vapor is recovered. In addition, at least in the process from the formation of the oil-based ink image by the ejection head 22 to the fixing by the fixing device 5, it is desirable that nothing is kept in contact with the image on the plate material 9.

The printing plate obtained is printed by a known lithographic printing method. That is, the printing plate on which the oil-based ink image is formed is mounted on a printing press, and a printing ink and a dampening solution are applied to form a printing ink image. The printing ink image is formed on a blanket cylinder rotating together with the plate cylinder. Printing is performed, and then printing of one color is performed by transferring the printing ink image on the blanket cylinder onto printing paper passing between the blanket cylinder and the impression cylinder. After the printing is completed, the printing plate is removed from the plate cylinder, and the blanket on the blanket cylinder is cleaned by the blanket cleaning device, and is ready for the next printing.

Next, the ink jet drawing apparatus 2 will be described. As shown in FIG. 3, the ink jet drawing apparatus 2 used in the plate making apparatus includes an ink jet discharge head 22 and an ink supply unit 24. Ink supply unit 2
Reference numeral 4 further includes an ink tank 25, an ink supply device 26, and an ink concentration control unit 29. The ink tank 25 includes a stirring unit 27 and an ink temperature management unit 28. The ink may be circulated in the ejection head 22, and in this case, the ink supply unit 24 also has a recovery circulation function. Stirring means 27
Is a re-dispersion means for re-dispersing the ink by a stirring action or the like, which suppresses precipitation and aggregation of the solid components of the ink, and reduces the necessity of cleaning the ink tank 25. As the stirring means 27 for re-dispersion, a rotating blade, an ultrasonic vibrator, and a circulation pump can be used, and these are used or in combination. The details will be described later. The ink temperature management unit 28 is arranged so that a high-quality image can be stably formed without changing the physical properties of the ink due to a change in ambient temperature and without changing the dot diameter. As the ink temperature control means, a heater, a heating element such as a Peltier element, or a cooling element is arranged in the ink tank 25 together with the stirring means 27 so as to keep the temperature distribution in the ink tank 25 constant, and a temperature sensor, for example, A known method such as control using a thermostat or the like can be used. The temperature of the ink in the ink tank 27 is desirably from 15 ° C to 60 ° C, and more desirably from 20 ° C to 50 ° C. Further, the stirring means for keeping the temperature distribution in the ink tank 25 constant may be shared with the stirring means for suppressing the precipitation and aggregation of the solid components of the ink. Note that the ink supply device 2
4, the ink may be circulated in the head as shown in FIG. As shown in FIG. 4, the ink supply unit also has a collecting and circulating function using a pump 26 'and a valve 61' for circulating and collecting ink from the head 22. By arranging a filtering means such as a filter immediately before the discharge head 22, it is possible to supply a cleaner ink that does not include paper fibers or dust to the discharge head 22.

The plate making apparatus preferably has an ink density control means 29 in order to perform high-quality drawing. As a result, it is possible to effectively suppress the occurrence of bleeding on the plate due to a decrease in the solid concentration in the ink, the jump or blur of the printed image, or the change in the dot diameter on the plate due to the increase in the solid concentration. The ink concentration is measured by optical detection, physical property measurement such as conductivity measurement, viscosity measurement, or management based on the number of drawn images. In the case of performing management by physical property measurement, an optical detector, a conductivity measuring instrument, and a viscosity measuring instrument are provided alone or in combination in the ink tank 25 or the ink flow path, and drawing is performed by an output signal thereof. In the case of performing management by the number of sheets, the supply of liquid from a replenishing concentrated ink tank or a diluting ink carrier tank (not shown) to the ink tank 25 is controlled according to the number of plate making and the frequency.

As described above, the image data calculation control unit 21 calculates the input image data, and controls the head separation / contact device 31,
Alternatively, in addition to the movement of the ejection head 22 by the head sub-scanning means 32, a timing pulse from the encoder 30 provided on the drum 11 or the capstan roller is taken in, and the ejection head 22 is driven according to the timing pulse. Thereby, the position accuracy can be improved.

Next, the ejection head 22 will be described with reference to FIGS.
1 will be described. However, the content of the present invention is not limited to the following.

FIGS. 5 and 6 show an example of the discharge head provided in the ink jet drawing apparatus. Discharge head 22
Has a slit sandwiched between an upper unit 221 and a lower unit 222 made of an insulating base material, the tip of which is a discharge slit 22a, and a discharge electrode 22b is arranged in the slit. Is supplied to the inside of the slit.
Examples of the insulating substrate include plastic, glass,
Ceramics and the like can be applied. Also, the discharge electrode 22b
Is a vacuum deposition, sputtering, or electroless plating of a conductive material such as aluminum, nickel, chromium, gold, and platinum on the lower unit 222 made of an insulating base material,
A photoresist is applied thereon, the photoresist is exposed through a mask having a predetermined electrode pattern, and the photoresist is exposed and developed to form a photoresist pattern of the discharge electrode 22b. Then, the photoresist pattern is etched or removed mechanically. It is formed by a known method such as a method or a method combining them.

As shown in FIG. 5, a drum 11 serving as a counter electrode is provided at a position facing a discharge electrode 22b provided on a discharge head 22, and a plate material is provided on the drum 11 serving as a counter electrode. 9 are provided. When a voltage is applied to the discharge electrode 22b according to the digital signal of the pattern information of the image, a circuit is formed between the discharge electrode 22b and the drum 11 serving as a counter electrode, and the oil-based ink 23 is discharged from the discharge slit 22a of the head 22. An image is formed on the plate material 9 provided on the drum 11 which is discharged and becomes a counter electrode.

The width of the discharge electrode 22b is preferably as narrow as possible in order to form a high quality image. Specific numerical values vary depending on conditions such as applied voltage and ink physical properties, but are usually used in a range of a tip width of 5 to 100 μm. For example, a discharge electrode 22b having a tip of 20 μm width is used, a distance between the discharge electrode 22b and the drum 11 serving as a counter electrode is set to 1.0 mm, and a voltage of 3 KV is applied between the electrodes for 0.1 millisecond to form a dot of 40 μm. To plate material 9
Can be formed on.

FIGS. 7 and 8 are a schematic sectional view and a schematic front view, respectively, showing the vicinity of the ink discharge portion of another discharge head. In the drawing, reference numeral 22 denotes a discharge head, and the discharge head 22 has a first insulating base material 33 having a gradually decreasing shape. A second insulating substrate 34 is provided on the first insulating substrate 33 so as to be spaced apart and opposed to the first insulating substrate 33, and a slope portion 35 is formed at the tip of the second insulating substrate 34. The first and second insulating substrates are made of, for example, plastic, glass, ceramics, or the like. A plurality of ejection electrodes 22b are provided on an upper surface 36 of the second insulating base 34, which forms an acute angle with the inclined surface 35, as an electrostatic field forming means for forming an electrostatic field in the ejection portion. The tips of the plurality of ejection electrodes 22 b are extended to near the tips of the upper surface 36, and the tips are formed of the first insulating base 33.
It projects more forward than it forms a discharge section. An ink inflow path 37 is formed between the first and second insulating bases 33 and 34 as a means for supplying the ink 23 to the discharge unit. An ink recovery path 38 is formed. The discharge electrode 22b is
Using a conductive material such as aluminum, nickel, chromium, gold, and platinum on the second insulating base material 34, as described above,
It is formed by a known method. The individual electrodes 22b are configured to be electrically insulated from each other.

The amount by which the tip of the discharge electrode 22b projects from the tip of the insulating substrate 33 is preferably 2 mm or less. The reason that the protrusion amount is preferable in the above range is that if the protrusion amount is too large, the ink meniscus does not reach the tip of the discharge unit,
This is because ejection becomes difficult and the recording frequency decreases. The space between the first and second insulating bases 33 and 34 is preferably in the range of 0.1 to 3 mm. The reason why this space is preferable in the above range is that if the space is too narrow, it becomes difficult to supply ink and it becomes difficult to discharge, or the recording frequency is lowered, and if the space is too wide, the meniscus is not stable. This is because the ejection becomes unstable.

The ejection electrode 22b is connected to the image data calculation control unit 21. When recording is performed, a voltage is applied to the ejection electrode based on the image information so that the ink on the ejection electrode is ejected. Drawing is performed on a plate material (not shown) arranged opposite to the plate material. The direction opposite to the ink droplet ejection direction of the ink inflow path 37 is connected to an ink feeding unit of an ink supply device (not shown). The second insulating substrate 3
A backing 39 is provided on the surface opposite to the ejection electrode forming surface of No. 4 so as to be spaced apart and opposed, and an ink recovery path 38 is provided between the two. The space of the ink recovery path 38 is 0.1
mm or more is desirable. The reason that this space is preferable in the above range is that if the space is too narrow, it becomes difficult to collect the ink, which may cause ink leakage. The ink recovery path 38 is connected to an ink recovery means of an ink supply device (not shown).

When a uniform ink flow on the ejection section is required, a groove 40 may be provided between the ejection section and the ink recovery section. FIG. 8 is a schematic front view of the vicinity of the ink ejection portion of the ejection head.
A plurality of grooves 40 are provided toward 8. This groove 4
A plurality of inks 0 are arranged in the direction in which the ejection electrodes 22b are arranged, and a certain amount of ink near the tip of the ejection electrode is guided from the opening on the ejection electrode 22b side by a capillary force according to the opening diameter. Is discharged to the ink recovery path 38. For this reason, it has a function of forming an ink flow having a constant liquid thickness near the tip of the discharge electrode. The shape of the groove 40 may be any range as long as the capillary force acts, and particularly preferably, the width is 10 to 200 μm and the depth is 10 to 300 μm.
It is in the range of μm. The necessary number of grooves 40 are provided so that a uniform ink flow can be formed over the entire surface of the ejection head.

The width of the discharge electrode 22b is preferably as narrow as possible in order to form a high quality image. Specific numerical values vary depending on conditions such as applied voltage and ink physical properties, but are usually used in a range of a tip width of 5 to 100 μm.

FIGS. 9 and 10 show another example of the ejection head used to carry out the present invention. FIG. 9 is a schematic view showing only a part of the head for explanation. As shown in FIG. 9, the ejection head 22 is a head body 4 made of an insulating material such as plastic, ceramic, glass, or the like.
1 and meniscus regulating plates 42 and 42 '. In the figure, 2
Reference numeral 2b denotes an ejection electrode for applying a voltage to form an electrostatic field in the ejection portion. Further, from the ejection head 22 to the regulating plate 4
The head body will be described in detail with reference to FIG.

The head body 41 is provided with a plurality of ink grooves 43 for circulating ink perpendicular to the edge of the head body. The shape of the ink groove 43 may be set in a range where the capillary force acts so that a uniform ink flow can be formed, and particularly preferably, the width is 10 to 200 μm.
m, the depth is 10 to 300 μm. The ejection electrode 22b is provided inside the ink groove 43. The discharge electrode 22b is formed on the head body 40 made of an insulating material by using a conductive material such as aluminum, nickel, chromium, gold, or platinum by a known method similar to that of the above-described apparatus embodiment. It may be arranged on the entire surface in the groove 43 or may be formed only on a part thereof. The discharge electrodes are electrically isolated. Two adjacent ink grooves form one cell, and ejection parts 45 and 45 'are provided at the end of the partition wall 44 at the center. In the discharge portions 45 and 45 ', the partition walls are thinner than the other partition portions 44 and are sharpened. Such a head body is formed by a known method such as machining, etching, or molding of an insulating material block. The thickness of the partition wall at the discharge portion is preferably 5 to 100 μm, and the radius of curvature of the sharpened tip is preferably 5 to 50 μm. The tip of the discharge section may be slightly chamfered, such as 45 '. Although only two cells are shown in the figure, the cells are separated by a partition wall 46, and the front end portion 47 is chamfered so as to be retracted from the discharge portions 45 and 45 '.
Ink is supplied to the ejection head from an I direction through an ink groove by an ink sending means of an ink supply device (not shown) to supply the ink to the ejection unit. Further, surplus ink is collected in the O direction by an ink collecting unit (not shown), and as a result, fresh ink is always supplied to the ejection unit. In this state, ink is ejected from the ejection unit by applying a voltage to the ejection electrode (not shown) corresponding to the image information on a drum (not shown) holding the plate material on the surface thereof in such a manner as to face the ejection unit. An image is formed on the material.

Another embodiment of the ejection head will be described with reference to FIG. As shown in FIG. 11, the ejection head 22 has a pair of substantially rectangular plate-shaped support members 50 and 50 '. These support members 50 and 50 'are formed of a plate-like plastic, glass, ceramic, or the like having a thickness of 1 to 10 mm having an insulating property. Each of the grooves 51, 5 is formed with a plurality of elongated rectangular grooves 51, 51 '.
1 'preferably has a width of 10 to 200 [mu] m and a depth of 10 to 300 [mu] m, and the discharge electrode 22b is formed entirely or partially inside. Thus, by forming the plurality of structures 51, 51 'on one surface of the support members 50, 50', a plurality of rectangular partition walls 52 are inevitably provided between the structures 51. Each support member 50, 50 '
Are combined so that the surfaces on which the grooves 51 and 51 'are not formed face each other. That is, the ejection head 22 has a plurality of grooves on the outer peripheral surface for flowing ink.
Grooves 51, 51 'formed in each support member 50, 50'
Are connected in a one-to-one relationship via a rectangular portion 54 of the discharge head 22, and the rectangular portion 54 to which each groove is connected is a predetermined distance (50 to 500 μm) from the upper end 53 of the discharge head 22.
m) has receded. That is, on both sides of each rectangular portion 54, the upper end 55 of each partition 52 of each support member 50, 50 '.
Are provided so as to protrude from the rectangular portion 54. A guide projection 56 made of an insulating material as described above is provided so as to protrude from each rectangular portion 54 to form a discharge portion.

When the ink is circulated through the ejection head 22 configured as described above, the ink is supplied to each rectangular portion 54 through each groove 51 formed on the outer peripheral surface of one of the support members 50, and the ink is supplied to the opposite side. Each groove 5 formed in the supporting member 50 '
Discharge via 1 '. In this case, the ejection head 22 is inclined at a predetermined angle to enable smooth ink distribution. In other words, the ejection head 22 is inclined such that the ink supply side (support member 50) is located above and the ink discharge side (support member 50 ') is located below.
Thus, when the ink is circulated through the ejection head 22,
The ink passing through each rectangular portion 54 wets along each protrusion 56, and an ink meniscus is formed near the rectangular portion 54 and the protrusion 56. Then, in a state where independent ink meniscuses are formed in the respective rectangular portions 54,
Ink is ejected from the ejection unit to apply a voltage to the ejection electrode 22b based on image information to a drum (not shown) holding the plate material on the surface thereof, and the ink is ejected from the ejection unit onto the plate material. An image is formed. By providing a cover for covering the groove on the outer peripheral surface of each support member 50, 50 ', a pipe-shaped ink flow path is formed along the outer peripheral surface of each support member 50, 50'. May be forcibly circulated. In this case, it is not necessary to tilt the ejection head 22.

The ejection head 22 described above with reference to FIGS. 5 to 11 can also include a maintenance device such as a cleaning means, if necessary. For example, when the pause state is continued or when a problem occurs in image quality, the tip of the ejection head is brushed with a flexible brush, a brush, a cloth, or the like, only the ink solvent is circulated, only the ink solvent is supplied, Alternatively, a good drawing state can be maintained by performing means such as sucking the discharge portion while circulating the ink alone or in combination. In order to prevent the ink from sticking, it is effective to cool the head and suppress evaporation of the ink solvent. If the contamination is further severe, the ink is forcibly sucked from the ejection part, the jet of air, ink, or ink solvent is forcibly injected from the ink flow path, or the ultrasonic wave is applied with the head immersed in the ink solvent. Is also effective, and these methods can be used alone or in combination.

Next, the plate material (printing plate) used in the present invention will be described. Examples of the printing original plate include a metal plate such as an aluminum plate or a chrome-plated steel plate. In particular, an aluminum plate having excellent surface water retention and abrasion resistance by graining and anodizing is preferable. As an inexpensive plate material, a plate material provided with an image receiving layer on a water-resistant support such as water-resistant paper, a plastic film, or paper laminated with plastic can be used. The thickness of the plate material is suitably in the range of 100 to 300 μm, and the thickness of the image receiving layer provided is suitably in the range of 5 to 30 μm.

As the image receiving layer, a hydrophilic layer comprising an inorganic pigment and a binder, or a layer which can be made hydrophilic by a desensitizing treatment can be used.

As the inorganic pigment used in the hydrophilic image receiving layer, clay, silica, calcium carbonate, zinc oxide, aluminum oxide, barium sulfate and the like can be used. Further, as a binder, polyvinyl alcohol, starch,
Hydrophilic binders such as carboxymethylcellulose, hydroxyethylcellulose, casein, gelatin, polyacrylate, polyvinylpyrrolidone, and polymethylether-maleic anhydride copolymer can be used. If necessary, a melamine formalin resin, a urea formalin resin, or another crosslinking agent for imparting water resistance may be added.

On the other hand, examples of the image receiving layer used after the desensitization treatment include a layer using zinc oxide and a hydrophobic binder.

The zinc oxide to be used in the present invention may be, for example, zinc oxide, zinc white, or zinc oxide, as described in “Pigment Handbook” edited by Japan Pigment Technical Association, p. Any of those commercially available as wet zinc white or activated zinc white may be used. That is, zinc oxide includes, as a dry method, a French method (indirect method), an American method (direct method), and a wet method, depending on the starting materials and the production method. For example, Shodo Chemical Co., Ltd. ), Hakusui Chemical Co., Ltd., Honjo Chemical Co., Ltd., Toho Zinc Co., Ltd., and Mitsui Kinzoku Kogyo Co., Ltd.

As the resin used as the binder, specifically, a styrene copolymer, a methacrylate copolymer,
Examples include an acrylate copolymer, a vinyl acetate copolymer, polyvinyl butyral, an alkyd resin, an epoxy resin, an epoxy ester resin, a polyester resin, and a polyurethane resin. These resins may be used alone or 2
More than one species may be used in combination. The content of the resin in the image receiving layer is represented by a weight ratio of resin / zinc oxide, 9/91 to 2/9.
It is preferably 0/80.

Desensitization of zinc oxide is carried out by a conventional method using a desensitizing solution. Conventionally, as this type of desensitizing solution, a processing solution containing a ferrocyanate salt or a ferricyan salt as a main component has been used. , Ammine cobalt complex, phytic acid and its derivatives, a treatment solution containing guanidine derivative as a main component,
There are known a treatment liquid mainly containing an inorganic acid or an organic acid which forms a chelate with zinc ions, or a treatment liquid containing a water-soluble polymer. For example, as a ferrocyanide salt-containing treatment solution, Japanese Patent Publication No. 44-9045,
39403, JP-A-52-76101, 57-1
Nos. 07889, 54-117201 and the like.

The surface of the plate material opposite to the image receiving layer is
The Beck smoothness is preferably in the range of 150 to 700 (sec / 10 cc). As a result, the formed printing plate does not shift or slip on the plate cylinder even during printing,
Good printing is performed.

Here, the Beck smoothness can be measured by a Beck smoothness tester. A Beck smoothness tester is a tester that applies a test piece to a highly smooth finished circular glass plate having a hole in the center at a constant pressure (1 kgf / cm ² (9.8 N).
/ Cm ² )) to measure the time required for a fixed amount (10 cc) of air to pass between the glass surface and the test piece under reduced pressure.

The oil-based ink used in the present invention will be described below. The oil-based ink used in the present invention is obtained by dispersing solid and hydrophobic resin particles at least at room temperature in a non-aqueous solvent having a specific electric resistance of 10 ⁹ Ωcm or more and a dielectric constant of 3.5 or less.

[0066] the specific electrical resistance 10 ⁹ Ωcm to be used in the present invention
As the nonaqueous solvent having a dielectric constant of 3.5 or less, preferably a linear or branched aliphatic hydrocarbon, alicyclic hydrocarbon, or aromatic hydrocarbon, and a halogen-substituted product of these hydrocarbons are used. is there. For example, hexane, heptane,
Octane, isooctane, decane, isodecane, decalin, nonane, dodecane, indodecane, cyclohexane, cyclooctane, cyclodecane, benzene, toluene, xylene, mesitylene, isoper C, isoper E, isoper G, isoper H, isoper L (isoper: exon , Shelsol 70, Shelsol 71 (Shellsol: trade name of Shell Oil), Amsco OMS, Amsco 460 solvent (Amsco: trade name of Spirits), silicone oil, etc., alone or as a mixture. Used. The upper limit of the specific electric resistance of such a non-aqueous solvent is about 10 ¹⁶ Ωcm, and the lower limit of the dielectric constant is about 1.9. These specific water solvents may be used alone or as a mixture with other solvents as a washing liquid.

The reason why the electric resistance of the non-aqueous solvent used is within the above range is that when the electric resistance is low, the concentration of the resin particles and the like becomes difficult to occur, and sufficient printing durability cannot be obtained. The reason for setting the above range is that when the dielectric constant is increased, the electric field is relaxed due to the polarization of the solvent, whereby the ejection of the ink tends to be deteriorated.

The resin particles dispersed in the above non-aqueous solvent may be any hydrophobic resin particles which are solid at a temperature of 35 ° C. or lower and have a good affinity for the non-aqueous solvent. Glass transition point is -5 ° C to 110 ° C or softening point 33 ° C
The resin (P) having a glass transition point of 10 to 100 ° C or a softening point of 38 to 1 ° C is more preferable.
20 ° C., more preferably 15 ° C.
80 ° C or a softening point of 38 ° C to 100 ° C.

By using a resin having such a glass transition point or softening point, the affinity between the surface of the image receiving layer of the printing original plate and the resin particles is increased, and the bonding between the resin particles on the printing original plate is increased. Therefore, the adhesion between the image portion and the image receiving layer is improved, and the printing durability is improved. On the other hand, regardless of whether the glass transition point or the softening point is low or high, the affinity between the image receiving surface and the resin particles is reduced, and the bonding between the resin particles is weakened.

The weight average molecular weight Mw of the resin (P) is 1 ×
10 ³ to 1 × 10 ⁶ , preferably 5 × 10 ³ to 8
× 10 ⁵ , more preferably 1 × 10 ^{4 to} 5 × 10 ⁵ .

Specific examples of the resin (P) include:
Olefin polymers and copolymers (eg, polyethylene, polypropylene, polyisobutylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer,
Ethylene-methacrylate copolymer, ethylene-methacrylic acid copolymer, etc.), vinyl chloride polymer and copolymer (eg, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, etc.), vinylidene chloride copolymer, alkane Vinyl acid polymers and copolymers, allyl alkanoate polymers and copolymers, polymers and copolymers of styrene and its derivatives (eg, butadiene-styrene copolymer, isoprene-styrene copolymer, styrene-methacrylate copolymer) Polymer, styrene-acrylate copolymer, etc.), acrylonitrile copolymer, methacrylonitrile copolymer, alkyl vinyl ether copolymer, acrylate polymer and copolymer, methacrylate polymer and copolymer, Itaconic acid diester polymer and copolymer, maleic anhydride Phosphate copolymers, acrylamide copolymers, methacrylamide copolymers, Funinoru resin,
Alkyd resin, polycarbonate resin, ketone resin, polyester resin, silicone resin, amide resin, hydroxyl and carboxyl group-modified polyester resin, butyral resin, polyvinyl acetal resin, urethane resin, rosin resin, hydrogenated rosin resin, petroleum resin, hydrogenated Petroleum resin, maleic acid resin, terpene resin, hydrogenated terpene resin, cumarone-indene resin, cyclized rubber-methacrylate copolymer, cyclized rubber-acrylate copolymer, heterocycle containing no nitrogen atom Copolymers (for example, heterocycles such as a furan ring, a tetrahydrofuran ring, a thiophene ring, a dioxane ring, a dioxofuran ring, a lactone ring, a benzofuran ring, a benzothiophene ring, and a 1,3-dioxetane ring), and an epoxy resin. Can be

The content of the dispersed resin particles in the oil-based ink of the present invention is preferably 0.5 to 20% by weight of the whole ink. If the content is low, it becomes difficult to obtain an affinity between the ink and the surface of the printing original plate, so that a good image cannot be obtained, or problems such as reduced printing durability are likely to occur. When the number of inks increases, it is difficult to obtain a uniform dispersion liquid, and the ink flow in the discharge head tends to be uneven, so that it is difficult to obtain stable ink discharge.

The oil-based ink used in the present invention preferably contains a coloring material as a coloring component together with the above-mentioned dispersed resin particles, for example, for plate inspection of a plate after plate making.
As the colorant, any pigments and dyes conventionally used in oil-based ink compositions or liquid developers for electrostatography can be used.

As the pigments, those generally used in the technical field of printing can be used irrespective of inorganic pigments and organic pigments. Specifically, for example, carbon black, cadmium red, molybdenum red, Chrome yellow, cadmium yellow, titanium yellow, chromium oxide, viridian, cobalt green, ultramarine blue, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment, quinacridone pigment, isoindolinone pigment, dioxazine pigment, sulene Conventionally known pigments such as pigments, perylene pigments, perinone pigments, thioindigo pigments, quinophthalone pigments, metal complex pigments and the like can be used without particular limitation.

As the dyes, azo dyes, metal complex dyes,
Naphthol dye, anthraquinone dye, indigo dye,
Oil-soluble dyes such as carbonium dyes, quinone imine dyes, xanthene dyes, aniline dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, phthalocyanine dyes and metal phthalocyanine dyes are preferred. These pigments and dyes may be used alone or in an appropriate combination, but are preferably contained in the range of 0.01 to 5% by weight based on the whole ink.

These coloring materials may be dispersed in a non-aqueous solvent as the coloring materials themselves as dispersed particles separately from the dispersed resin particles, or may be contained in the dispersed resin particles. In the case of containing, pigments and the like are generally coated with the resin material of the dispersed resin particles to obtain resin-coated particles. General.

The resin particles dispersed in the non-aqueous solvent of the present invention, and also the colored particles and the like, preferably have an average particle diameter of 0.05 μm to 5 μm. More preferably, it is 0.1 μm to 1.0 μm. This particle size is CAPA-
500 (trade name, manufactured by Horiba, Ltd.).

The non-aqueous dispersed resin particles used in the present invention can be produced by a conventionally known mechanical pulverization method or polymerization granulation method. As a mechanical grinding method,
If necessary, a material as resin particles is mixed, melted and kneaded, and then directly pulverized by a conventionally known pulverizer to obtain fine particles, a dispersing polymer is used in combination, and a wet disperser (for example, a ball mill, paint shaker) , Keddy mill, Dyno mill, etc.)
A method is known in which a dispersion-assisting polymer (or a coating polymer) is kneaded in advance to form a kneaded product, then pulverized, and then dispersed in the presence of a dispersing polymer. Specifically, a method for producing a paint or a liquid developer for electrostatography can be used. For example, these are described in Kenji Ueki, “Flow of paint and pigment dispersion”, Kyoritsu Shuppan (1971), Solomon “ Paint Science "Hirokawa Shoten (1969), Yuji Harasaki" Coating Engineering "Asakura Shoten (1971), Yuji Harasaki" Basic Science of Coatings "Maki Shoten (1977) and other books.

Examples of the polymerization granulation method include a conventionally known nonaqueous dispersion polymerization method. Specifically, Chapter 2 of Soichi Muroi, “Latest Technology of Ultrafine Polymer,” CMC Publishing (1991) ), Koichi Nakamura, "Recent Electrophotographic Development System and Development and Practical Use of Toner Materials", Chapter 3, (Nippon Scientific Information Co., Ltd., 1985), KEJ Barrett, "Dispersi
on Polymerization Organic Media "John Wiley (19
75 years).

Usually, a dispersion polymer is used in combination to stabilize the dispersion of the dispersed particles in a non-aqueous solvent. The dispersed polymer contains a repeating unit soluble in a non-aqueous solvent as a main component, and has an average molecular weight of 1 × 10 in weight average molecular weight Mw.
^It is preferably ³ to 1 × 10 ⁶ , more preferably 5 × 10 ³
５5 × 10 ⁵ .

Preferred soluble repeating units of the dispersion polymer used in the present invention include a polymerization component represented by the following general formula (I).

[0082]

Embedded image

In the general formula (I), X ₁ is —COO
Represents-, -OCO- or -O-. R represents 10 carbon atoms
Represents an alkyl group or an alkenyl group having from 32 to 32, preferably represents an alkyl group or an alkenyl group having from 10 to 22 carbon atoms, and may be linear or branched. It may be. Specifically, decyl group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosanyl group, docosanyl group, decenyl group, dodecenyl group, tridecenyl group, hexadecenyl group, octadecenyl group, linolenyl group, and the like. .

A₁And a_TwoAre the same or different
May be a hydrogen atom, a halogen atom (eg, chlorine
Atom, bromine atom, etc.), cyano group, alkyl having 1 to 3 carbon atoms
(For example, methyl group, ethyl group, propyl group, etc.),
-COO-Z₁Or -CH _TwoCOO-Z₁[Z₁Is
An optionally substituted hydrocarbon group having 22 or less carbon atoms (eg,
For example, alkyl group, alkenyl group, aralkyl group, alicyclic
A formula group, an aryl group, etc.).

Among the hydrocarbon groups represented by Z ₁ , preferred hydrocarbon groups include alkyl groups having 1 to 22 carbon atoms which may be substituted (for example, methyl group, ethyl group, propyl group, butyl group, Hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tridecyl,
Tetradecyl group, hexadecyl group, octadecyl group, eicosanyl group, docosanyl group, 2-chloroethyl group,
A bromoethyl group, a 2-cyanoethyl group, a 2-methoxycarbonylethyl group, a 2-methoxyethyl group, a 3-bromopropyl group, etc., and an optionally substituted alkenyl group having 4 to 18 carbon atoms (for example, 2-methyl- 1-propenyl group, 2-butenyl group, 2-pentenyl group, 3-methyl-
2-pentenyl group, 1-pentenyl group, 1-hexenyl group, 2-hexenyl group, 4-methyl-2-hexenyl group, decenyl group, dodecenyl group, tridecenyl group, hexadecenyl group, octadecenyl group, linolenyl group, etc.),
An aralkyl group having 7 to 12 carbon atoms which may be substituted (for example, benzyl group, phenethyl group, 3-phenylpropyl group, naphthylmethyl group, 2-naphthylethyl group, chlorobenzyl group, bromobenzyl group, methylbenzyl group, An ethylbenzyl group, a methoxybenzyl group, a dimethylbenzyl group, a dimethoxybenzyl group, etc., an alicyclic group having 5 to 8 carbon atoms which may be substituted (for example, cyclohexyl group,
-Cyclohexylethyl group, 2-cyclopentylethyl group and the like, and an optionally substituted aromatic group having 6 to 12 carbon atoms (for example, phenyl group, naphthyl group, tolyl group, xylyl group, propylphenyl group, butylphenyl group) Octylphenyl, dodecylphenyl, methoxyphenyl, ethoxyphenyl, butoxyphenyl, decyloxyphenyl, chlorophenyl, dichlorophenyl, bromophenyl, cyanophenyl, acetylphenyl, methoxycarbonylphenyl, ethoxy Carbonylphenyl group, butoxycarbonylphenyl group, acetamidophenyl group, propionamidophenyl group, dodecyloylamidophenyl group, etc.).

In the dispersion polymer, another repeating unit may be contained as a copolymer component together with the repeating unit represented by the general formula (I). Other copolymer components include:
Any compound may be used as long as it is composed of a monomer copolymerizable with a monomer corresponding to the repeating unit of the general formula (I).

The proportion of the polymer component represented by the general formula (I) in the dispersion polymer is preferably at least 50% by weight, more preferably at least 60% by weight. Specific examples of these dispersion polymers are described in JP-A-10-20
No. 4354, No. 10-204356, No. 10-259
No. 336, No. 10-306244, No. 10-3169
No. 17, No. 10-316920, etc., and the dispersion stabilizing resin (Q-1) used in Examples, and a commercially available product (Solprene 1205, manufactured by Asahi Kasei Corporation). It can also be used.

When the above-mentioned resin (P) particles are produced as a dispersion (latex) or the like, the dispersion polymer is preferably added in advance during the polymerization. When the dispersing polymer is used, the addition amount is 1 to 50 based on the resin for particles (P).
% By weight.

The dispersed resin particles and the colored particles (or the coloring material particles) in the oil-based ink of the present invention are preferably positively or negatively chargeable particles. In order to impart an electric detecting property to these particles, it can be achieved by appropriately using a technique of a developer for wet electrophotography. Specifically, the aforementioned “Recent development and practical use of electrophotographic development systems and toner materials”, pp. 139-148, edited by the Society of Electrophotographic Engineers, “Basics and Application of Electrophotographic Technology”, pp. 497-505 (Corona 1988)
Annual), Yuji Harasaki "Electrophotography" 16 (No. 2), 44
The method is performed by using an electric detection material such as a charge control agent described on page (1977) and other additives.

Specifically, for example, British Patent No. 8934
No. 29, No. 934038, No. 11222397,
U.S. Pat. No. 3,900,412, equivalent 4,606,899,
JP-A-60-179751, JP-A-60-185963
And JP-A-2-13965.
The charge control agent as described above is used as the carrier liquid dispersion medium 10.
0.001 to 1.0 part by weight is preferable for 00 parts by weight. If desired, various additives may be added. The upper limit of the total amount of these additives is regulated by the electrical resistance of the oil-based ink. That is, if the specific electric resistance of the ink from which the dispersed particles have been removed is lower than 10 ⁹ Ωcm, it becomes difficult to obtain a high-quality continuous tone image. desirable.

Hereinafter, the re-dispersion of the ink will be described.
If the ink flows in the ink tank and the ink particles agglomerate and / or settle, clogging of the pipe and clogging of the head will occur, and ink ejection will become unstable. Therefore, the ink particles are made uniform by re-dispersing these aggregates and sediments. The re-dispersion can be achieved by an action including any one of stirring, dispersion, mixing, and jetting. In addition, each action can be applied singly, in a plurality, or in multiples according to the capacity and type of the ink, and can be applied as needed, periodically or continuously. By disposing the re-dispersion means upstream of the ink ejection section, uniform ink particles can be supplied to the ink ejection section. It is more effective to provide a pipeline stirrer immediately before the ink discharge unit. When the ink flow is restarted after the suspension, the redispersion unit is operated before the ink flow is restarted to uniform the ink particles so that aggregates and sediments are not supplied to the ink discharge unit. It is effective. By replacing the redispersion means in the ink flow path as a cartridge type, redispersion means having different functions can be adaptively selected according to the capacity and type of ink, and maintenance is improved. I do.

As a specific example of the redispersing means, a stirrer having a disk shape or a fan shape and having a peripheral speed of 1 to 3000 rpm, a high speed rotating special stirrer, and the like, having a stirrer having a disk shape or a fan shape are provided. A homomixer that consists of a turbine with a shape and a stator with radial baffles, agitates agglomerates, etc. by utilizing the fact that ink is ejected by the pressure difference created between the bottom and top of the turbine due to high-speed rotation of the turbine. Pipeline mixer, magnet mixer (magnetic stirrer, star head stirrer, etc., manufactured by Tokai Riki Co., Ltd.) that stirs aggregates by rotating stirring blades arranged on the road, and stirs aggregates by ultrasonic vibration・ Dispersion super-vibration stirrer, which has a structure in which two disks with honeycomb-shaped walls are placed on top of each other, and rotates a disk (stirring disk) More Ramon de stirrer underside of axial center beyond the sucked honeycomb walls ink stirring the ink is blown from the side surface (Tokai physical machine manufactured by (Ltd.)) can be mentioned. In addition, a homogenizer (manufactured by Nippon Seiki Seisakusho, etc.) that disperses aggregates and the like by rotating a stirring blade, and an ultrasonic homogenizer (Japan Co., Ltd.) that disperses aggregates and the like by ultrasonic vibration are provided as dispersing agents. Ultrasonic filter (manufactured by Ginsen Co., Ltd.) that vibrates the filter surface at high speed to disperse aggregates, high-speed disperser (Keddy Mill), ultrasonic cleaner (Nippon Seiki Seisakusho) Manufactured by Nippon Techno Co., Ltd.)
Stirrer, etc.). In addition, a mixing pump (manufactured by Nippon Ball Valve Co., Ltd.) that enables uniform mixing by a two-liquid mixing function, and a plurality of stirring blades attached to a rotating shaft in a vessel are used as a device exhibiting a mixing action. And an in-line mixer (Dynamic Mixer manufactured by Nippon Ball Valve Co., Ltd.) for mixing. In addition, a pump which has a jet effect (underwater) (such as a product of Lacey Co., Ltd.) may be mentioned. Each of the above means is preferably arbitrarily miniaturized and partially improved for use in the present invention. These re-dispersion means exhibit a single action such as stirring and mixing, respectively, and effectively perform re-dispersion by a combined action such as stirring and mixing.

[0093]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited to these examples. First, a production example of the ink resin particles (PL) will be described.

Production Example 1 of Resin Particles (PL-1) A mixed solution of 10 g of a dispersion stabilizing resin (Q-1) having the following structure, 100 g of vinyl acetate and 384 g of Isopar H was heated to a temperature of 70 ° C. while stirring under a nitrogen stream. did. 2,2'-azobis (isovaleronitrile) as a polymerization initiator
0.8 g (abbreviation AIVN) was added and reacted for 3 hours. Twenty minutes after the initiator was added, cloudiness occurred and the reaction temperature rose to 88 ° C. Furthermore, 0.5 g of this initiator was added, and after reacting for 2 hours, the temperature was raised to 100 ° C., and the mixture was stirred for 2 hours to distill off unreacted vinyl acetate. After cooling, the mixture was passed through a 200-mesh nylon cloth, and the resulting white dispersion was a latex having a degree of polymerization of 90% and an average particle size of 0.23 μm and having good monodispersity. The particle size was measured with CAPA-500 (manufactured by Horiba, Ltd.).

[0095]

Embedded image

A part of the white dispersion was centrifuged (rotation speed: 1 × 10 ⁴ rpm, rotation time: 60 minutes), and the precipitated resin particles were collected and dried. Weight average molecular weight of resin particles (Mw: GPC in terms of polystyrene)
Value) was 2 × 10 ⁵ , and the glass transition point (Tg) was 38 ° C.

Example 1 First, an oil-based ink was prepared. <Preparation of oil-based ink (IK-1)> 10 g of dodecyl methacrylate / acrylic acid copolymer (copolymerization ratio: 95/5 weight ratio), 10 g of nigrosine and Shellsol 7
1 g together with glass beads was placed in a paint shaker (manufactured by Toyo Seiki Co., Ltd.) and dispersed for 4 hours to obtain a fine dispersion of nigrosine. Production example 1 of resin particles for ink
60 g (as a solid content) of the resin particles (PL-1) produced in the above, 2.5 g of the above nigrosine dispersion, FOC-14
00 (Nissan Chemical Co., Ltd., tetradecyl alcohol) 1
A black oil-based ink was prepared by diluting 5 g, and 0.08 g of octadecene-half-maleic acid octadecylamide copolymer into 1 liter of Isopar G.

Next, a plate making apparatus (see FIGS. 1, 3 and 4)
2 liters of the oil-based ink (IK-1) prepared as described above was filled in the ink tank of the first inkjet drawing apparatus 2. Here, 900d shown in FIG.
A pi, 64 channel multi-channel head was used. A piezoelectric pump was used for sending the ink. A throwing heater and a stirring blade 71 (Ramond stirrer (model number ST02) manufactured by Tokai Riki Co., Ltd.) are provided in the ink tank 25 as ink temperature management means, and the ink temperature is set to 30 ° C.
The temperature was controlled with a thermostat while rotating the stirring blade 71 at 30 rpm. The stirring blade 71 was used by being driven by a stirring motor 70 (a simple stirrer (model number K-1R) manufactured by Tokai Riki Co., Ltd.) as a re-dispersion means for preventing sedimentation and aggregation. Further, the ink flow path is partially transparent, and an LED light emitting element and a light detecting element are arranged with the ink flow path interposed therebetween. The concentration was adjusted by doubling the concentration).

As a plate material, a 0.12 mm-thick aluminum plate subjected to graining and anodizing treatment was mounted with a plate head and a plate edge added by a mechanical device provided on a drum of a plate making device. After removing dust from the surface of the plate by suction with an air pump, move the discharge head close to the plate until the drawing position,
The image data to be made was transmitted to the image data calculation control unit, and the 64-channel ejection head was moved while rotating the drum, thereby ejecting oily ink onto the aluminum plate to form an image. At this time, the tip width of the ejection electrode of the ink jet head was set to 10 μm, and the distance between the head and the plate material was controlled to be 1 mm based on the output from the optical gap detector. A voltage of 2.5 KV is constantly applied as a bias voltage, and when discharging, a pulse voltage of 500 V is further superimposed, and the pulse voltage is 256 steps within a range of 0.2 to 0.05 ms. The drawing was performed while changing the area of the dot by changing.
No drawing defects due to ink agglomerates and dust were observed at all, and no image deterioration due to a change in dot diameter or the like was observed even when the outside air temperature changed or the number of plate making increased, and good plate making was possible.

Further, the image was strengthened by heating with a xenon flash fixing device (luminous intensity: 200 J / pulse, manufactured by Ushio Inc.) to produce a printing plate. In order to protect the ink jet head, the ink jet drawing apparatus is retracted by 50 mm from the position adjacent to the drum together with the sub-scanning means.
It was mounted on a plate cylinder of a 66EPZ printing machine and printing was performed.

The obtained printed product was an extremely clear image without any skipping or blurring in the printed image even after passing through 10,000 sheets. Also, for 10 minutes after the end of the plate making, the isoper G is supplied to the head, the isoper G is dripped from the head opening, and the head is stored in a cover filled with vapor of the isoper G after cleaning. For three months, a printing plate giving good printed matter could be produced without the need for maintenance work. During this period, when left for one week, the ink settled to the bottom of the tank and became a bulky aggregate. Plate making was possible.

Embodiment 2 An apparatus shown in FIG. 12 in which the redispersion means (the stirring motor 70 and the stirring blade 71) of the ink jet drawing apparatus 24 shown in FIG.
A dpi full line inkjet head was arranged. Micro gear pump (Chuo Rika Kogyo Co., Ltd.)
Ink reservoirs are respectively provided between the pump and the ink inflow passage of the ejection head, and between the ink recovery passage of the ejection head and the ink tank, and the ink is circulated by a difference in hydrostatic pressure between the ink reservoirs. , A heater and the above-described pump were used, the ink temperature was set to 35 ° C., and the temperature was controlled by a thermostat. Here, as a circulation pump, a submersible pump (Lacy pump (model number P-112) manufactured by Lacey Co., Ltd.) shown at 72 in the figure was also used as a redispersion means for preventing precipitation and aggregation. Then, an electric conductivity measuring device was arranged in the ink flow path, and the density was controlled by diluting the ink or feeding the concentrated ink based on the output signal. The above-described aluminum plate was similarly mounted on a drum of a plate-making apparatus as a plate material. After removing dust on the surface of the plate using a rotating brush made of nylon, the image data to be made is transmitted to the image data calculation control unit, and the plate material is drawn by a full line head while transporting the plate using a capstan roller. An image was formed by discharging oil-based ink onto the aluminum plate. No defective drawing due to the aggregates of the ink was observed at all, and no image deterioration due to a change in the dot diameter was observed even when the outside air temperature was changed or the number of plate making was increased, and good plate making was possible. Further, it is heated by fixing with a heat roller (Teflon (registered trademark) sealed silicone rubber roller containing a 300 W halogen lamp) (pressure: 3 kgf / cm ^2).
(29.4 N / cm ² )) The image was strengthened and a printing plate was prepared.

Further, when printing was performed on the prepressed plate in the same manner as in Example 1, the printed image was extremely clear without any skipping or blurring even after 10,000 sheets were passed. In addition, after circulating Isopar G in the head after the completion of plate making, cleaning was performed by contacting a non-woven fabric containing Isopar G to the tip of the head, and a good printed matter was obtained for three months without maintenance work. The printing plate to be given could be made. Further, when the same operation was performed using a 600 dpi full-line ink jet head of the type shown in FIGS. 8 and 10 instead of the ink jet head of the type shown in FIG. 6, good results were obtained in the same manner as described above. . In any case, it takes a long time to obtain a normal dispersion state by using only the liquid sending pump, but when using the redispersion means, the ink returns to a good dispersion state in a very short time,
High-quality drawing was possible.

Example 3 In place of the aluminum plate of Example 1, a plate material provided with an image receiving layer which can be made hydrophilic by a desensitizing treatment was used on the surface shown below, and the plate surface was rendered insensitive to oil after forming the plate. The non-image area is hydrophilized using a surface treatment device, the plate material conductive layer is grounded by contact with a conductive leaf spring (made of phosphor bronze) during drawing, and fixing is performed by applying hot air to the plate material. Is Example 1
The same operation was performed.

A high-quality paper having a basis weight of 100 g / m ² was used as a substrate. The layer coating is applied on one side, and after drying, the applied amount is 10 g / m ² .
Further, the dispersion A was dried thereon and dried at a coating amount of 15 g /
An image receiving layer was provided so as to obtain a plate material of m ² .

Paint for conductive layer; carbon black (30
% Aqueous dispersion), 5.4 parts, clay (50% aqueous dispersion) 5
4.6 parts, SBR latex (solid content 50%, Tg 25
C) 36 parts and melamine resin (solid content 80%, Sumiretz Resin SR-613) 4 parts were mixed, and the total solid content was 2
Water was added so as to be 5% to obtain a paint.

Dispersion A: 100 g of dry zinc oxide, 3 g of binder resin (B-1) having the following structure, and 1 binder resin (B-2)
A mixture of 7 g, 0.15 g of benzoic acid and 155 g of toluene was mixed with a wet disperser homogenizer (manufactured by Nippon Seiki Co., Ltd.).
For 8 minutes at 6,000 rpm.

[0108]

Embedded image

When fixing was performed by blowing hot air on the plate material, blisters were generated. Therefore, the fixing was performed by gradually increasing the supply power to the heater used for the hot air or by gradually decreasing the rotation speed of the drum from high speed to low speed without changing the supply power.
As a result, no blister was generated, and the printed matter obtained by printing the printing plate was an extremely clear image without any skipping or blurring in the printed image even when the number of sheets passed 5,000.

Example 4 Instead of the stirring blade 71 of Example 1, a redispersing means shown in FIG. 13 was used. That is, the stirrer 81 (star head stirrer manufactured by Tokai Riki Co., Ltd. (size 5
8)), and a stirrer 82 (a magnetic stirrer manufactured by Tokai Riki Co., Ltd. (model number H)) provided outside the ink tank 25.
S-50E)), the ink was stirred.

Example 5 Instead of the stirring blade 71 of Example 1, a redispersing means shown in FIG. 14 was used. That is, as the ink tank 25, an ultrasonic bath 83 (Ultrasonic cleaner manufactured by Tokai Riki Co., Ltd. (model number US
Using K-2)), the ink was dispersed by ultrasonic vibration.

Example 6 Instead of the stirring blade 71 of Example 1, a redispersing means shown in FIG. 15 was used. That is, the vibrator 84 (φ5) is put into the ink tank 25, and the vibrator 84 is vibrated by the oscillator 85 (ultrasonic disperser (model number UH-50) manufactured by Tokai Riki Co., Ltd.) to disperse the ink. did.

Example 7 Instead of the stirring blade 71 of Example 1, a re-stirring means shown in FIG. 16 was used. That is, a multistage vibrating blade (single shaft type) 86 is put into the ink tank 25, and a low frequency is transmitted to the vibrating blade 86 from the vibrator 87 (super vibration α-stirrer manufactured by Nippon Techno Co., Ltd.). The ink was stirred by the frequency vibration.
In the seventh embodiment, the stirring is not performed by the rotation of the stirring blade as in the first embodiment, but the stirring is performed by the vibration of the stirring blade. Therefore, there is no possibility that air is mixed into the ink. In addition, since the blades do not rotate, they can be installed at the outermost end of the ink tank, and the degree of freedom of installation is large.

On the other hand, in Examples 1 to 7, 3 to
In the case where redrawing is performed without performing stirring and dispersion in advance after the ink liquid flow is stopped for 10 days, the ejection becomes unstable from the beginning in any of the embodiments, and the image is disturbed or the non-ejection state continues. In the worst case, the ejection openings of the head were completely blocked by solid agglomerates of the majority of the ink particles, and rendering was impossible.

The means for preventing aggregation and sedimentation or for re-dispersion shown in the above-described embodiments may be of a large size for a production line. It is preferable to improve the size of the plate making apparatus according to the present invention after appropriately reducing the size.

[0116]

According to the present invention, it is possible to prepare a printing plate capable of printing a large number of clear images. In addition, a printing plate directly corresponding to digital image data can be stably created with high image quality, and low-cost and high-speed lithographic printing can be performed. Further, by providing means for re-dispersing aggregates and precipitates, a high-quality printing plate can be produced.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram schematically showing one example of a plate making apparatus used in the present invention.

FIG. 2 is an overall configuration diagram schematically showing another example of the plate making apparatus used in the present invention.

FIG. 3 is a configuration diagram schematically illustrating an example of a drawing unit of the plate making apparatus used in the present invention.

FIG. 4 is a configuration diagram of an apparatus to which an ink circulation function is added.

FIG. 5 is a schematic configuration diagram showing an example of an ejection head provided in an ink jet drawing apparatus used in the present invention.

FIG. 6 is a schematic cross-sectional view of the vicinity of an ink ejection unit in FIG.

FIG. 7 is a schematic cross-sectional view of an example of another ejection head provided in the inkjet drawing apparatus used in the present invention, in the vicinity of an ink ejection section.

FIG. 8 is a schematic front view of the vicinity of the ink ejection unit in FIG. 7;

FIG. 9 is a schematic configuration diagram showing a main part of an example of another ejection head provided in the ink jet drawing apparatus used in the present invention.

FIG. 10 is a schematic configuration diagram of a head obtained by removing a regulating plate from the ejection head of FIG. 9;

FIG. 11 is a schematic configuration diagram showing a main part of an example of another ejection head provided in the ink jet drawing apparatus used in the present invention.

12 is a configuration diagram of an apparatus in which a part of the apparatus shown in FIG. 4 is replaced.

FIG. 13 is a schematic sectional view showing a re-dispersion unit.

FIG. 14 is a schematic sectional view showing a re-dispersion unit.

FIG. 15 is a schematic sectional view showing a re-dispersion unit.

FIG. 16 is a schematic sectional view showing a re-dispersion unit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 plate making device 2 inkjet drawing device 5 fixing device 6 plate surface desensitizing device 7 plate material automatic plate feeding device 8 plate material automatic plate discharging device 9 plate material (printing original plate) 10 dust removing means 11 drum 12 capstan roller 13 grounding means 21 Image data calculation control unit 22 Discharge head 221 Upper unit 222 Lower unit 22a Discharge slit 22b Discharge electrode 23 Oil-based ink 24 Ink supply unit 25 Ink tank 26 Ink supply device 27 Stirring unit 28 Ink temperature management unit 29 Ink density control unit 30 Encoder 31 Head separation / attachment device 32 Head sub-scanning means 33 First insulating base material 34 Second insulating base material 35 Slope portion of second insulating base material 36 Upper surface portion of second insulating base material 37 Inflow of ink Road 38 Ink recovery path 39 Backing 40 Groove 41 Head book 42, 42 'Meniscus regulating plate 43 Ink groove 44 Partition wall 45, 45' Ejection part 46 Partition wall 47 Partition end part 50, 50 'Support member 51, 51' Groove 52 Partition wall 53 Upper end part 54 Rectangular part 55 Upper end of partition 56 Guide projection 61, 61 'Valve 70 Stirring motor 71 Stirring blade 72 Pump 81 Stirrer 82 Stirrer 83 Ultrasonic bath 84 Ultrasonic vibrator 85 Ultrasonic oscillator 86 Vibrating blade 87 Vibrator

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B41J 2/185 B41J 3/04 102H 2/06 102R B41M 5/00 103G (72) Inventor Mutsumi Nanka Haibara-gun, Shizuoka 4000 Kawajiri, Yoshida-machi Fuji Sha Shin Film Co., Ltd.F-term (reference) 2H084 AA25 AA38 AE05 BB02 BB04 BB16 CC05 2H086 BA54 BA55

Claims (23)

[Claims] 1. An image is formed directly on a plate material by an electrostatic ink jet method in which an oil-based ink is discharged using an electrostatic field based on a signal of image data, and the image is fixed to form a printing plate. A plate making method, characterized in that at least aggregates and / or sediments of the oil-based ink particles, which are generated due to static flow of the ink or the like, are redispersed. 2. The method according to claim 1, wherein the oil-based ink has a specific electric resistance value of 10.
The plate making method according to claim 1, wherein solid and hydrophobic resin particles are dispersed at least at room temperature in a non-aqueous solvent having a dielectric constant of ⁹ Ωcm or more and 3.5 or less. 3. An image forming means for forming an image directly on a plate material by an ink jet drawing apparatus for discharging an oil-based ink from a discharge head using an electrostatic field based on a signal of image data, and forming the image by the image forming means. A plate fixing device for fixing a formed image to obtain a printing plate, comprising a means for redispersing aggregates and / or sediments of the oil-based ink particles generated at least by ink flow stoppage or the like. A plate-making apparatus, characterized in that: 4. The plate-making apparatus according to claim 3, wherein at least a means for re-dispersing aggregates and / or sediments of ink particles is provided immediately before the ink discharge section of the discharge head. 5. The means for re-dispersing aggregates and / or sediments of ink particles, at least before ink flow and / or
The plate making device according to claim 3, wherein the plate making device operates simultaneously. 6. The means for redispersing aggregates and / or sediments of ink particles comprises one of stirring, dispersion, mixing, and jetting.
4. The method according to claim 3, wherein the operation is performed by the following operations.
The plate making apparatus according to claim 5. 7. The plate making apparatus according to claim 3, wherein the stirring, dispersing, mixing, and jetting actions are applied singly, in plurality, or in multiples. 8. The plate making apparatus according to claim 3, wherein the stirring, dispersing, mixing, and jetting actions are applied as needed, periodically or continuously. 9. The prepress according to claim 3, wherein the means for redispersing the aggregates and / or sediments of the ink particles is replaceable as a cartridge type. apparatus. 10. The oil-based ink has a specific electric resistance value of 1.
In a non-aqueous solvent having a dielectric constant of not less than 0 ⁹ Ωcm and not more than 3.5,
The plate making apparatus according to any one of claims 3 to 9, wherein solid and hydrophobic resin particles are dispersed at least at room temperature. 11. The image fixing means has a heating means using a heat roller and / or an infrared lamp, a halogen lamp or a xenon flash lamp.
11. The plate-making apparatus according to any one of claims 10 to 10. 12. The plate making apparatus according to claim 11, wherein the heating means is arranged and / or controlled so as to gradually increase the temperature of the plate material when fixing the image. 13. The plate making apparatus according to claim 3, wherein a main scan is performed by rotating a drum on which the plate is mounted when drawing on the plate. 14. The plate making apparatus according to claim 13, wherein the discharge head is a single-channel head or a multi-channel head, and performs sub-scanning by moving the discharge head in a direction parallel to the axis of the drum. 15. The plate making apparatus according to claim 3, wherein at the time of drawing on the plate material, sub-scanning is performed by nipping and moving the plate material by at least a pair of capstan rollers. . 16. The prepress according to claim 15, wherein the discharge head is a single-channel head or a multi-channel head, and performs main scanning by moving the discharge head in a direction orthogonal to a direction in which the printing plate travels. apparatus. 17. The discharge head comprises a full line head having a length substantially equal to a width of the printing plate.
Alternatively, the plate making apparatus according to claim 15. 18. The plate making apparatus according to claim 3, wherein the ink jet drawing apparatus has an ink supply unit that supplies the oil-based ink to the discharge head. 19. The plate making apparatus according to claim 18, further comprising an ink collecting means for collecting the oil-based ink from the ejection head, and performing ink circulation. 20. The apparatus according to claim 3, further comprising dust removing means for removing dust existing on the surface of the plate material before and / or during drawing on the plate material. Plate making equipment. 21. The ink-jet drawing apparatus according to claim 3, wherein the ink-jet drawing apparatus has an ink temperature management unit that manages a temperature of the oil-based ink in an ink tank that stores the oil-based ink. Plate making equipment. 22. The plate making apparatus according to claim 3, wherein the ink jet drawing apparatus has an ink density control unit for controlling the density of the oil-based ink. 23. The plate making apparatus according to claim 3, further comprising cleaning means for cleaning said discharge head.