JP2001171069A - Plate making method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing plate by directly forming an image on a plate material using a rapid ink jet recording method which is free from ink oozing and shows a high image resolution and an easy conversion to a line head configuration and further, ensures a stable drive under a low cost operation. SOLUTION: This plate making device has an ink jet image drawing device 2 equipped with a discharge head for spewing insulating ink to the plate material 9, arranged opposite to the plate material 9, a voltage applying means which applies bias voltage to the discharge head for forming an electrostatic field and applies modulated voltage obtained through modulation based on an image data signal and a light emission means which emits light to the insulating ink. The insulating ink is spewed to the plate material 9 from the discharge head to form an image directly on the plate material 9 by forming the electrostatic field at the discharge head by the voltage applying means and at the same time, applying the modulated voltage to the discharge head by the voltage applying means in such a state that the light is emitted to the insulating ink by the light emitting means.

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 for forming a plate image by flying ink using an electrostatic field.

[0002]

2. Description of the Related Art In lithographic printing, a printing plate is provided with a printing ink receptive region and a printing ink repellent region corresponding to an image original, and printing is performed by adhering printing ink to the ink receiving region. . 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.

To record an image on a printing plate (plate making), an image document 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 plate) is printed. Is generally performed by exposing the non-image area to elution and removal mainly using an alkaline solution.

In recent years, in the lithographic printing method, due to the recent improvement in 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 Pri
nting Plate).

As a plate making method, for example, there is a system for recording an image in an optical mode or a thermal mode by using a laser. In general, after the laser recording, a non-image portion is dissolved and removed by treating with an alkaline developing solution. Since plate making is performed, alkaline waste liquid is discharged, which is not preferable in terms of environmental conservation. In addition, the method using a laser is expensive and requires a large device.

On the other hand, a system using an ink jet method has been attempted as a new plate making method. The method using the inkjet method forms an image by flying ink droplets on a plate material, and is inexpensive and compact as compared with the case of using the laser, and further, does not require melting and removing. There is an advantage that there is no problem of waste liquid.

As a method of flying an ink drop, a method of flying an ink drop by the pressure of steam generated by the heat of a heating element (for example, Japanese Patent Publication No. 56-9429 and Japanese Patent Publication No. 61-1986)
A typical example is a method in which an ink droplet is caused to fly by a mechanical pressure pulse generated by a piezoelectric element. Further, as a head for ejecting ink droplets, a serial scanning type head mounted on a carriage and performing recording while moving in a direction (main scanning direction) perpendicular to a recording paper conveyance direction (sub scanning direction) is cited. But it is difficult to increase the recording speed. Also,
There is a line scanning type head in which the recording head is a long head having the same size as the width of the recording paper. However, although the recording speed is high, since a large number of nozzles are provided, a decrease in reliability due to clogging is inevitable. Further, the conventional flying method has a problem that it is difficult to improve the resolution. That is, in the flying method using the pressure of steam, it is difficult to generate ink particles having a diameter of 20 μm or less, and the ink particles bleed on the recording medium, so that recording dots having a diameter of 50 μm or less are generated. It will be difficult. Further, in the flying system using the pressure generated by the piezoelectric element, the recording head has a complicated structure, and therefore, it is difficult to produce a high-resolution head even with a problem in processing technology.

As a method for overcoming the above-mentioned drawbacks relating to the recording head, there has been proposed a method in which a voltage is applied to a thin-film electrode array, and an ink or a colorant component in the ink is ejected from an ink liquid surface using an electrostatic force. More specifically, a method of flying ink using electrostatic attraction (Japanese Patent Laid-Open No. 49-620)
No. 24, JP-A-56-4467, etc.) and a system in which an ink containing charged colorant particles is used to increase the concentration of the colorant and fly (WO93 / 11866: PCT / AU92 /
00665).

In these systems, the recording head has a slit-shaped nozzle structure that does not require a nozzle for each individual dot, or a nozzleless structure that does not require a partition of an ink flow path for each individual dot. This is effective for preventing and recovering from clogging which has been a major obstacle in realizing a line scanning type recording head. In particular, the latter can stably generate and fly ink droplets having a very small diameter, and is suitable for high resolution because there is no bleeding because the colorant particles in the ink fly mainly. In a conventional ink jet recording apparatus using a method in which a colorant flies by such an electrostatic force, a recording head having an electrode array in which electrodes are arranged as described above is used, and several hundreds to several The ink is caused to fly by applying a high voltage of KV.

[0010]

However, when a multi-nozzle head having a plurality of ink ejection ports, such as a line scanning recording head, is constructed by using such an electrode array, if the voltage applied to the electrodes is high, the adjacent nozzles will become adjacent. Electric field interference between the electrodes becomes a problem. In general, the voltage signal for normal flight is created by controlling the output voltage from the high-voltage power supply on and off with a driving driver. When the applied voltage is high, a driver with a high withstand voltage must be used. Yes,
It will be expensive. To prevent these problems, the distance between the recording head and the recording medium may be reduced to reduce the applied voltage. In that case, the thickness of the recording medium,
The effect of paper dust and dust tends to occur, making it difficult to draw stably.

An object of the present invention is to solve the above-mentioned problems. That is, it has high resolution without bleeding,
It is an object of the present invention to provide a plate making method and a plate making apparatus capable of forming an image directly on a plate material to obtain a printing plate by a high-speed ink jet recording method which can be driven stably, is inexpensive, easily made into a line head, and provided. is there.

[0012]

The above object is achieved by the following (1).
To (20). (1) A plate making method for forming an image directly on a plate material based on a signal of image data, fixing the image, and creating a printing plate used for lithographic printing, wherein an insulating ink is applied to the plate material. A modulation voltage modulated based on a signal of the image data is supplied to the discharge heads which are arranged opposite to each other, and a voltage modulated based on the signal of the image data is applied to the discharge head while forming an electrostatic field on the discharge head and irradiating the insulating ink with light. A plate making method, wherein an image is formed directly on the plate material by applying the applied insulating ink to fly from the discharge head.

(2) The insulating ink is obtained by dispersing solid colored particles at least at room temperature in a non-aqueous solvent having a specific electric resistance of 10 ⁹ Ωcm or more and a non-dielectric constant of 3.5 or less. The plate making method described in (1)).

(3) The plate making method according to (1) or (2), wherein the light includes a wavelength at which the light is absorbed by the insulating ink.

(4) A plate making apparatus comprising image forming means for forming an image directly on a plate material based on a signal of image data, wherein the plate material on which the image is formed is used as a printing plate for lithographic printing. An ejection head that is disposed to face the plate material and that causes insulating ink to fly on the plate material, and a bias voltage is applied to form an electrostatic field in the ejection head,
A voltage application unit that applies a modulation voltage that is modulated based on the image data signal, and a light irradiation unit that irradiates light to the insulating ink, including an inkjet drawing apparatus, and the voltage application unit While forming an electrostatic field on the ejection head, and irradiating the insulating ink with the light by the light irradiating means, further applying the modulation voltage to the ejection head by the voltage applying means, A plate-making apparatus, wherein an image is formed directly on the plate material by causing a fusible ink to fly from the discharge head to the plate material.

(5) The insulating ink is obtained by dispersing solid colored particles at least at room temperature in a non-aqueous solvent having a specific electric resistance of 10 ⁹ Ωcm or more and a non-dielectric constant of 3.5 or less. The plate making device according to (1).

(6) The plate making method according to (4) or (5), wherein the light irradiating means irradiates light having a wavelength absorbed by the insulating ink.

(7) The plate making apparatus according to any one of (4) to (6), further comprising an image fixing unit for fixing the image formed by the image forming unit.

(8) Further, any one of (4) to (7), further including dust removing means for removing dust present on the surface of the printing plate before and / or during writing on the printing plate. A plate-making apparatus according to item 1.

(9) The plate making apparatus according to any one of (4) to (8), 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.

(10) The sub-scan is performed in that the discharge head has a single head or a multi-head shorter than the width of the plate material, and the sub-scan is performed by moving the discharge head in the axial direction of the drum. Plate making equipment.

(11) 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 (4) to (8).
A plate-making apparatus according to any one of the above.

(12) The discharge head has a single head or a multi-head shorter than the width of the plate material, and performs main scanning by moving the discharge head in a direction perpendicular to the direction of travel of the plate material. The plate making device according to (11).

(13) The plate making apparatus according to (9) or (11), wherein the discharge unit has a full line head having a length substantially equal to a width of the plate material.

(14) The plate making apparatus according to any one of (4) to (13), wherein the ink jet drawing apparatus further includes an ink supply unit for supplying the insulating ink to the discharge head.

(15) The plate making apparatus according to (14), wherein the ink jet drawing apparatus further comprises an ink collecting means for collecting surplus ink from the discharge head, and circulates ink.

(16) The ink jet drawing apparatus according to any one of (4) to (15), further comprising stirring means for stirring the insulating ink in an ink tank storing the insulating ink. Plate making equipment.

(17) The ink jet drawing apparatus further comprises an ink temperature management means for managing the temperature of the insulating ink in the ink tank storing the insulating ink. (4) to (16) A plate-making device according to one of the preceding claims.

(18) The plate making apparatus according to any one of (4) to (17), wherein the ink jet drawing apparatus further includes an ink density control means for controlling the density of the insulating ink.

(19) The ink jet drawing apparatus further includes a separation / contact means for separating / contacting the discharge head from / to the plate material, and the discharge head is separated / contacted from the plate material except during drawing. 4) The plate making apparatus according to any one of the above items (18) to (18).

(20) The plate making apparatus according to any one of (4) to (19), further comprising cleaning means for cleaning the discharge section at least after the completion of plate making.

[0032]

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 on a plate material by an inkjet method in which an insulating ink is discharged by an electrostatic field to obtain a printing plate used for lithographic printing. In the inkjet method of the present invention, the size of the ejected ink droplet is determined by the size of the ejection electrode. For this reason, if a small ejection electrode is used, it is possible to reduce the ejection nozzle diameter or the ejection slit width without reducing it.
Small ink droplets are obtained. Therefore, the present invention relates to a plate-making method and a plate-making apparatus for a plate material capable of printing a large number of prints of a clear image without the problem of head clogging.

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 grounding function as a counter electrode of the discharge head electrode in the electrostatic field discharge. Therefore, when the drum is formed of an insulator such as plastic or glass, it is preferable to provide a conductive layer on the surface by a known method such as sputtering, vapor deposition, and plating. On the other hand, when the insulating property of the substrate of the plate material is high, it is preferable to provide a conductive layer on the substrate. In this case, it is desirable to provide a means for grounding the conductive layer. Further, as described above, the drum 11
When a heat insulating material is provided on the upper side, 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 area.

The plate making device 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 as needed for the purpose of enhancing the hydrophilicity of the surface of the plate material 9 may be provided.
Further, the plate making apparatus 1 includes a dust removing unit 10 for removing dust existing on the surface of the plate material 9 before and / or during drawing on the plate material 9.
Having. Thereby, it is possible to effectively prevent the ink from adhering to the plate material 9 due to the transmission of dust between the ejection head and the plate material during plate making, and to perform good plate making. Dust removing means 10
In addition to known non-contact methods such as suction removal, blow-off removal, and electrostatic removal, a contact method using a brush, a roller, or the like can be used. In the present invention, desirably, any one of air suction, air blow-off, and the like Can be used in combination.

Further, the plate material 9 to be printed is transferred to the drum 11
An automatic plate feeding device 7 that automatically supplies the plate material to the top and an automatic plate discharging device 8 that automatically removes the plate material 9 after the drawing from the drum 11 may be provided. The use of the automatic plate feeding device 7 and the automatic plate discharging device 8 makes the plate making operation easier,
Further, since the plate making time can be reduced, the effect of the present invention can be further enhanced.

Referring to FIG. 1 and partly in FIG.
The process of producing a printing plate according to 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 printing plate 9 is closely fixed to the drum 11 by a mechanical method using a well-known printing head / butt holding device, an air suction device, or the like, or the like, whereby the printing edge of the printing plate flaps. It is possible to prevent the ink jet drawing device 2 from being damaged by contact with the ink jet drawing device 2. Means for adhering the plate material 9 to the drum 11 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 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 ejection head away from the printing plate material, which can effectively prevent the ink jet drawing apparatus 2 from causing troubles such as contact damage.

The image data arithmetic and 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 manner using the inkjet discharge head 22 (see FIG. 3 and described in detail later) included in the inkjet drawing apparatus 2, the halftone dot area ratio is also calculated. 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 lifting of the plate material or the dot diameter changing especially when vibration is applied to the plate making machine.

The ejection head 22 is a single head,
A multi-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-head or a full-line head having a plurality of discharge units, the arrangement direction of the discharge units is set in the axial direction of the drum 11. Further, in the case of a single head or a multi-head, the discharge head 22 is moved in the axial direction of the drum 11 by one rotation of the drum 11 by the image data calculation control unit 21 to obtain the discharge position and the dot area obtained by the above calculation. The oil-based ink is discharged onto the plate 9 mounted on the drum 11 at a predetermined rate. 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 behavior is
An oil-based ink image for one color of the printing original is formed on the plate material 9 and continues until a printing plate is completed. On the other hand, when the ejection head 22 is a full line head having a length substantially equal to the width of the drum 11, one rotation of the drum 11 forms an oil-based ink image of one color of a print document on the plate 9. A printing plate is completed. By performing the main scanning by rotating the drum 11 in this manner, the position 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 in a sliding manner, 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 as described above, 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, solvent fixing, and flash exposure fixing can be used. In the heat fixing, infrared rays, irradiation of a halogen lamp or a xenon flash lamp, hot air fixing using a heater, and heat roll fixing are generally used. In this case, in order to enhance the fixing property, the drum is heated, the plate material 9 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 and heating only the plate material 9 alone or in combination. When a paper plate material is used, the temperature inside the plate material rapidly evaporates due to a rapid rise in temperature, causing a phenomenon called blistering, in which irregularities occur on the plate material surface. It is preferable to gradually increase the power supply to the heat source while rotating the drum 11 so as to warm up, or to change the rotation speed from high speed to low speed with constant power supply. Further, a plurality of fixing units are arranged in the rotation direction of the drum 11, and the distance to the plate material 9 and / or
Alternatively, the paper plate material may be gradually heated by changing 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 steam, and excess solvent vapor is recovered. Flash fixing using a xenon lamp or the like is known as a fixing method for electrophotographic toner, and has an advantage that fixing can be performed in a short time. 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 preferable that nothing is kept in contact with the image on the plate material 9.

An example of the configuration 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 the drawing is performed by the ink jet drawing apparatus 2 so as to be a counter electrode of the discharge head electrode in the electrostatic field discharge, thereby facilitating the drawing. On the other hand, when the insulating property of the base of the plate 9 is high, it is preferable to provide a conductive layer on the base. In this case, the conductive layer is formed on the conductive layer by means of a known conductive brush, leaf spring, roller or the like. 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.

The plate making device 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 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 device 1 includes a dust removing unit 1 that removes dust existing on the plate material surface before and / or during drawing on the plate material 9.
Has zero. Thereby, it is possible to effectively prevent the ink from adhering to the plate material due to the transmission of dust between the discharge head and the plate material during the plate making, and to perform good plate making. Dust removing means 10
In addition to known non-contact methods such as suction removal, blow-off removal, and electrostatic removal, a contact method using a brush, a roller, or the like can be used. In the present invention, desirably, any one of air suction, air blow-off, and the like Can be used in combination.

Further, it is preferable to provide an automatic plate feeding device 7 for automatically supplying a plate material 9 to be used for printing, and an automatic plate discharging device 8 for automatically removing the plate material 9 after drawing from the drum 11. . Automatic plate feeding device 7 and automatic plate discharging device 8
By using, the plate making operation becomes simpler and the plate making time can be shortened, so that the effect 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, by providing a plate material guide means (not shown) as necessary, 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 to prevent the plate material 9 from contacting the ink jet drawing device 2 at least when drawing. You can also. Specifically, for example, there is a method of arranging a pressing roller upstream and downstream of the drawing position. Further, when no drawing is performed, it is desirable to keep the ejection head away from the plate material 9, which can effectively prevent the ink jet drawing device 2 from causing troubles such as contact damage.

Image data from a magnetic disk device or the like
The image data arithmetic control unit 21 calculates the discharge position of the oil-based ink and the halftone dot area ratio at that position in accordance with the input image data. These calculation 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 plate material 9 was maintained at a predetermined distance during drawing by mechanical distance control such as an abutment 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 lifting of the plate material or the dot diameter changing especially when vibration is applied to the plate making machine.

The ejection head 22 is a single head,
A multi-head or a full line head can be used, and sub-scanning is performed by transporting the plate material 9. In the case of a multi-head having a plurality of ejection sections, the arrangement direction of the ejection sections is set parallel or substantially parallel to the traveling direction of the printing plate. Further, in the case of a single head or a multi-head, the image data arithmetic control unit 21 controls the ejection head 2 for each plate material movement.
2 is moved in the direction orthogonal to the running direction of the printing plate 9, and the oil-based ink is discharged onto the printing plate 9 at the discharge position and the dot area ratio obtained by the above calculation. 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 a printing plate is completed. On the other hand, when the ejection head 22 is a full line head having substantially the same length as the width of the drum 9, the arrangement direction of the ejection portions is set to a direction orthogonal to or substantially orthogonal to the traveling direction of the plate material. As the printing paper 9 passes through the drawing unit, an oil-based ink image for one color of the printing original is formed on the printing plate 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 moves the ejection head to the drum 9 at least 500 μm except during drawing.
It operates so as to be separated. 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 retracting the ejection head during non-drawing in this way, 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, solvent fixing, and flash exposure fixing can be used. In the heat fixing, infrared rays, irradiation of a halogen lamp or a xenon flash lamp, hot air fixing using a heater, and heat roll fixing are generally used. When a paper plate is used, the water inside the plate evaporates rapidly due to a rapid rise in temperature, causing a phenomenon called blistering, in which irregularities occur on the surface of the plate. It is preferable to change the power supply and / or the distance to the plate material 9 of the fixing device so that the paper plate material gradually rises in temperature 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. Flash fixing using a xenon lamp or the like is known as a fixing method for electrophotographic toner, and has an advantage that fixing can be performed in a short time. 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 preferable that nothing is kept in contact with the image on the plate material 9.

The printing process after the printing plate is formed is the same as the known lithographic printing method. That is, the plate material 9 on which the oil-based ink image is drawn 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. Is transferred to the printing paper passing between the blanket cylinder and the impression cylinder, and then the printing ink image on the blanket cylinder is transferred to print one color. Plate 9 after printing
Is removed from the plate cylinder and the blanket on the blanket cylinder is cleaned by a blanket cleaning device to be ready for the next print.

Next, the ink jet drawing apparatus 2 will be described. As shown in FIG. 3, the inkjet drawing apparatus 2 used in the plate making apparatus includes an inkjet 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 density 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
Reduces the precipitation and aggregation of the solid components of the ink, thereby reducing the necessity of cleaning the ink tank 25. As the stirring means 27, a rotary blade, an ultrasonic vibrator, and a circulation pump can be used, and these are used or in combination. The ink temperature management means 28 is arranged such that a high-quality image can be stably formed without a change in the physical properties of the ink due to a change in the surrounding temperature and a change in 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 15 ° C. or more and 60 ° C.
C. or less, more preferably 20.degree. C. or more and 50.degree. C. or less. 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. Discharge head 22
Is irradiated with light L.

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. Ink density is measured by optical detection, conductivity measurement,
It is performed by measuring physical properties such as viscosity measurement, or by controlling the number of drawn images. When 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. When the management is performed by the number of sheets, the supply of the liquid from the replenishment concentrated ink tank or the dilution ink carrier tank (not shown) to the ink tank 25 is controlled based on 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 moving 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 cap stun 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.
This will be described using. However, the content of the present invention is not limited to the following.

In the figure, reference numeral 22 denotes a discharge head. The discharge head 22 has a first insulating substrate 33 having a gradually decreasing shape. The first insulating substrate 33 has the second insulating substrate 3
4 are provided so as to be spaced apart from each other.
A slope portion 35 is formed at the tip of the. The first,
The second insulating substrate is, for example, plastic, glass,
It is formed of ceramics or the like.

The discharge electrode 2 as a plurality of individual electrodes is formed as an electrostatic field forming means for forming an electrostatic field in the discharge section on the upper surface 36 which forms an acute angle with the slope 34 of the second insulating base material 34.
2b is provided. The tips of the plurality of ejection electrodes 22b extend to near the tips of the upper surface portion 36, and the tips protrude forward of the first insulating base material 33 to form ejection portions. An ink flow path 37 is formed between the first and second insulating bases 33 and 34 as a means for supplying the ink 7 to the ejection unit. An ink recovery path 38 as ink recovery means is formed.

The discharge electrode 22b is formed by depositing a conductive material such as aluminum, nickel, chromium, gold, or platinum on the second insulating base material 34 by vacuum deposition, sputtering, or electroless plating. A method of applying a resist, exposing the photoresist through a mask of a predetermined electrode pattern, developing the photoresist pattern of the discharge electrode 22b, and etching the photoresist pattern;
Alternatively, it is formed by a known method such as a method of mechanical removal or a combination thereof. The individual electrodes are configured to be electrically independent of each other.

The first and second insulating bases 33, 3
4 are opposed to each other, and are positioned with a space so that the tip of the discharge electrode 22 b protrudes from the tip of the insulating base material 33. The tip of the discharge electrode 22b is an insulating substrate 3
3 and 2 mm or less is preferable. If the amount of protrusion is too large, the ink meniscus does not reach the tip of the discharge unit, which makes it difficult to discharge or lowers the recording frequency. The space between the first and second insulating bases 33 and 34 is preferably in the range of 0.1 to 3 mm. If the space is too narrow, it becomes difficult to supply the ink and it becomes difficult to discharge the ink, or the recording frequency is lowered. If the space is too large, the meniscus is not stable and the discharge becomes unstable.

The ejection electrode 22b is connected to a signal power supply 61, and when recording is performed, as shown in FIG.
In a state where the upper ink is irradiated with light, a modulation voltage modulated by the image data operation control unit 21 based on the image data is applied from the signal power supply 12 to the discharge electrode, thereby discharging the ink, and Drawing is performed on a recording medium (not shown) arranged opposite to the recording medium. Here, the light irradiation is performed by light including a wavelength absorbed by the ink from a light irradiation unit (not shown). As the light irradiation unit, an exposure apparatus used in the technical field of plate making can be used. Known light sources such as lasers, LEDs, plasma light emitting arrays, light sources such as halogen lamps, xenon lamps, and fluorescent lamps can be used. The wavelength of the light irradiation means is selected in consideration of the absorption of the ink used.

The ink flow path 37 is connected to an ink supply device (not shown) in the direction opposite to the ink droplet ejection direction. A backing 39 is provided on the surface of the second insulating substrate 34 opposite to the surface on which the ejection electrodes are formed, facing away from each other, and an ink recovery path 38 is provided between the two. The space of the ink recovery path 38 is desirably 0.1 mm or more. If the space is too small, it becomes difficult to collect the ink, which may cause ink leakage. The ink recovery path 38 is connected to an ink suction means (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. 5 is a schematic front view showing the vicinity of the ejection portion of the ejection head. A plurality of grooves 40 are formed on the slope of the second insulating base material 34 from the vicinity of the boundary with the ejection electrode 22 b toward the ink recovery path 38. Is provided. This groove 40
A plurality of the ejection electrodes 22b are arranged in the arrangement direction, and have a function of guiding ink to each groove 40 from the opening on the ejection electrode 22b side by capillary force, and discharging the guided ink to the ink recovery path 38. The groove 40 sucks a certain amount of ink near the tip of the discharge electrode by a capillary force corresponding to the opening diameter. Therefore, it has a function of forming an ink flow having a constant liquid thickness near the tip of the discharge electrode. Groove 4
The shape of 0 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.
m. The necessary number of grooves 40 are provided so that a uniform ink flow can be formed over the entire surface of the head.

The width of the discharge electrode 22b is preferably as narrow as possible at the tip in order to form a high-quality image, for example, for printing. Specific numerical values vary depending on conditions and the like, but are usually used in a range of a tip width of 5 to 100 μm.

FIGS. 6 and 7 show another embodiment of the apparatus used to carry out the recording method of the present invention.

FIG. 6 is a schematic diagram showing only a part of the head for explanation. As shown in FIG. 6, the ejection head 22 includes a head body 41 made of an insulating material such as plastic, ceramic, and glass, and the meniscus regulating plate 4.
2, 42 '. In the drawing, reference numeral 22b denotes an ejection electrode for applying a voltage to form an electrostatic field in the ejection portion.

Further, the head main body will be described in detail with reference to FIG. 7 in which the regulating plates 42 and 42 'have been removed from the head. 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 works so that a uniform ink flow can be formed.
Particularly preferably, the width is 10 to 200 μm, and the depth is 10 to 3
00 μm. The ejection electrode 22 is provided inside the ink groove 43.
b is provided. The ejection electrode 22b is formed on the head body 22 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. May be arranged on the entire surface of the ink groove 43 or may be formed only on a part thereof. The discharge electrodes are electrically independent.

The two adjacent ink grooves form one cell, and the discharge portion 4
5, 45 'are provided. In the ejection portions 45 and 45 ', the partition walls are thinner than the other partition portions 44 and are sharpened. The tip of the discharge portion may be slightly chamfered as in 45 '. Such a head body is manufactured 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. Although only two cells are shown in the figure, the cells are separated by a partition wall 46, and the tip 47 thereof is connected to the discharge section 4
It is chamfered so that it is more retracted than 5, 45 '. The ink is supplied to the head by an ink supply unit (not shown).
The ink flows from the direction through the ink groove, and supplies the ink to the ejection unit.

Excess ink is collected in the O direction by an ink collecting means (not shown). As a result, fresh ink is always supplied to the ejection unit. In the state where light is irradiated to the ink near the discharge portion as shown in L, the ink is provided in a form facing the discharge portion, and the discharge electrode is in accordance with image data with respect to a counter electrode (not shown) holding a recording medium on its surface. By applying the modulated voltage modulated by the
Ink is ejected from 45 'to form an image on the recording medium. The light irradiating means is the same as that of the above-described apparatus embodiment, and the description is omitted.

Next, still another embodiment of the ejection head will be described with reference to FIG. As shown in FIG. 8, the discharge head 22 has a pair of substantially rectangular plate-shaped support members 50 and 50 '. These support members 50, 50 'are made of a plate-like plastic, glass, ceramic or the like having a thickness of 1 to 10 mm having an insulating property, and one surface of each is parallel to each other according to the recording resolution. A plurality of elongated rectangular grooves 51 and 51 '(not shown) are formed. Each groove 51, 51 'has a width of 10 to 200 μm and a depth of 1
The discharge electrode 22b is preferably formed in a range of 0 to 300 μm, and the whole or a part thereof is formed.
Thus, the plurality of grooves 5 are formed on one surface of the support members 50, 50 '.
By forming 1, 51 ', between each groove 51,
A plurality of rectangular partitions 52 are necessarily provided.

Each support member 50, 50 'is provided with a groove 51, 5'.
They are combined so that the surfaces not forming 1 'face each other. That is, the ejection head 22 has a plurality of grooves on the outer peripheral surface for flowing ink. Each support member 5
The grooves 51, 51 ′ formed at 0, 50 ′ are connected in a one-to-one correspondence via the upper end 53 of the discharge head 22, and the rectangular portion 54 to which each groove is connected is connected to the upper end of the discharge head 22. It is retracted from 53 by a predetermined distance (50 to 500 μm). That is, the supporting members 5 are provided on both sides of each rectangular portion 54.
The upper end 55 of each of the partition walls 52 of 0 and 50 ′ is provided so as to protrude from the rectangular portion 54. And each rectangular part 5
From 4, the guide projection 56 made of an insulating material as described above is provided so as to protrude 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 support member 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. That is, 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.
As described above, when the ink is circulated through the ejection head 22,
The ink passing through each rectangular portion 54 gets wet along each protrusion 56, and an ink meniscus is formed near the rectangular portion 54 and the protrusion 56. Then, an independent ink meniscus is formed at each rectangular portion 54, and the ink near the ejection portion is illuminated with light as shown at L, and is provided so as to face the ejection portion. By applying a modulation voltage to the held counter electrode (not shown) to the discharge electrode 22b based on image information, ink is discharged from the discharge unit and an image is formed on a recording medium.

By providing a cover for covering the groove on the outer peripheral surface of each support member 50, 50 ', each support member 50, 50' is provided.
A pipe-shaped ink flow path may be formed along the outer peripheral surface of 50 ', and ink may be forcibly circulated through the ink flow path. In this case, it is not necessary to tilt the ejection head 22. The light irradiating means is the same as that of the above-mentioned two embodiments, and the description is omitted.

The ejection head 22 described above with reference to FIGS. 4 to 8 can include a maintenance device such as a cleaning unit, if necessary. For example, when the hibernation state continues,
If a problem occurs with the image quality, the tip of the ejection head is brushed with a flexible brush, brush, cloth, or the like, circulates only the ink solvent, supplies only the ink solvent, or sucks the ejection portion while circulating, A good drawing state can be maintained by performing such means 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 section, the jet of air, ink, or ink solvent is forcibly injected from the ink flow path, or the ultrasonic wave is applied while the head is 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 metal plates such as aluminum and chrome-plated steel plates. 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, 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 used in the present invention may be, for example, zinc oxide, zinc oxide or zinc oxide, as described in “Pigment Handbook”, pp. 319, edited by the Japan Pigment Technical Association, Seibundo Co., Ltd. (1968). Any of those commercially available as wet zinc white or active zinc may be used. That is, zinc oxide includes, as dry methods, French methods (indirect methods), American methods (direct methods) and wet methods, depending on the starting materials and the production method. For example, Shodo Chemical Co., Ltd., Sakai Chemical Co., Ltd. ), Hakusui Chemical Co., Ltd., Honjo Chemical Co., Ltd., Toho Zinc Co., Ltd., Mitsui Kinzoku Kogyo Co., Ltd., and the like.

Specific examples of the resin used as a binder include vinyl chloride-vinyl acetate copolymer and styrene-
Butadiene copolymer, styrene-methacrylate copolymer, methacrylate copolymer, acrylate copolymer,
Examples include vinyl acetate copolymer, polyvinyl butyral, alkyd resin, epoxy resin, epoxy ester resin, polyester resin, and polyurethane resin. These resins may be used alone or in combination of two or more. The content of the resin in the image receiving layer is preferably from 9/91 to 20/80 in terms of resin / zinc oxide weight ratio.

Desensitization of zinc oxide has been conventionally performed by using a desensitizing treatment liquid of this type, a treatment liquid containing a cyanide compound containing ferrocyanate or ferricyanate as a main component, an ammine cobalt complex, phytic acid and derivatives thereof. There are known a cyan-free treatment liquid containing a guanidine derivative as a main component, a treatment liquid containing an inorganic acid or an organic acid that forms a chelate with zinc ions as a main component, and a treatment liquid containing a water-soluble polymer. For example, as a cyanide-containing treatment solution, JP-B-44-9045 and JP-B-46-39403.
And JP-A-52-76101 and 57-107889.
And No. 54-117201.

The surface of the plate 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 printing plate can be printed satisfactorily without causing displacement or slippage on the plate cylinder even during printing.

The Beck smoothness can be measured by a Beck smoothness tester. A Beck Smoothness Tester is a tester in which a test piece is placed at a constant pressure (1 kgf / cm ² (9.8 N) on a highly smooth finished circular glass plate with a hole in the center.
/ 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 may be one obtained by dispersing solid colored particles at least at room temperature in a non-aqueous solvent having a specific electric resistance of 10 ⁹ Ωcm or more and a relative dielectric constant of 3.5 or less. preferable. As the non-aqueous solvent having a specific electric resistance of 10 ⁹ Ωcm or more and a relative permittivity of 3.5 or less used in the present invention, preferably a linear or branched aliphatic hydrocarbon, alicyclic hydrocarbon, or aromatic hydrocarbon Examples include hydrogen and halogen-substituted products of these hydrocarbons, silicone liquids and silicone oils.

For example, as the hydrocarbon solvent, hexane, heptane, octane, isooctane, decane, isodecane, decalin, nonane, dodecane, isododecane, cyclohexane, cyclooctane, cyclodecane, benzene, toluene, xylene, mesitylene, isoper C,
Isopar E, Isopar G, Isopar H, Isopar L (Isoper; trade name of Exxon), Shelsol 70, Shersol 71 (Shelsol, trade name of Shell Oil), Amsco OMS, Amsco 460 solvent (Amsco; Spirits) Company name).

Fluorocarbon solvents are examples of halogen-substituted hydrocarbon solvents. For example, perfluoroalkanes represented by C _n F _{2n + 2} such as C ₇ F ₁₆ and C ₈ F ₁₈ (manufactured by Sumitomo 3M) "Fluorinert PF5080", "Fluorinert PF5070" (trade name), fluorocarbons ("Crytox GPL series" (trade name) manufactured by Dupont Japan Limited), and fluorocarbons ("FC-141b" manufactured by Daikin Industries, Ltd.) Etc.), "F (CF ₂ )
₄ CH ₂ CH ₂ I, "" F (CF _{2) 6} I "iodide fluorocarbons such as (Daikin Fine Chemical Laboratory, Ltd.," I
-1420 "," I-1600 "(product name) and the like.

Dialkyl polysiloxanes (eg, silicone liquids and silicone oils)
Hexylmethyldisilosane, tetramethyldisiloxane, octamethyltrisiloxane, hexamethyltrisiloxane, heptamethyltrisiloxane, decamethyltetrasiloxane, trifluoropropylheptamethyltrisiloxane, diethyltetramethyldisiloxane, etc.),
Cyclic dialkylpolysiloxane (for example, hexamethylcyclotrisiloxane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, tetramethylcyclotetrasiloxane, tetra (trifluoropropyl) tetramethylcyclotetrasiloxane, etc.), methylphenyl silicone oil ( For example, KF56, KF5
8 (trade name of Shin-Etsu Silicone Co., Ltd.) and the like. These solvents are used alone or as a mixture.

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 relative permittivity is about 1.9. If the specific electric resistance of the nonaqueous solvent used is too low, the ejection position of the ink is not stable, and bleeding is likely to occur, and if the specific resistance is too high, a high applied voltage is required. If the relative dielectric constant of the nonaqueous solvent used is too high, bleeding is likely to occur due to the ease of the electric field in the ink, and if the relative dielectric constant is too low, the ejection of the ink tends to be poor. is there.

Examples of the coloring material for the colored particles dispersed in the non-aqueous solvent include pigments and dyes conventionally used in oil-based ink compositions, liquid developers for electrostatography or electrophotographic photosensitive members. Although any can be used, pigments and dyes, especially for electrophotographic photoreceptors, give favorable results.

As the pigment, generally used pigments can be used irrespective of inorganic pigments and organic pigments.
Specifically, for example, azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, selen pigments, perylene pigments, perinone pigments, thioindigo pigments, quinophthalone pigments, metal complexes Conventionally known pigments such as pigments can be used without any 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 contained in the dispersed resin particles, or the coloring materials themselves may be dispersed as non-dispersed particles in a non-aqueous solvent. When it is contained, a method of coating pigments or the like with the resin material of dispersed resin particles to form resin-coated particles is generally used, and a method of coloring dyes or the like on the surface of the dispersed resin particles to form colored particles. Etc. are common.
On the other hand, when the coloring material itself is dispersed in the non-aqueous solvent as the dispersing particles, the dispersed resin particles in the range of 0.5 to 20% of the whole ink are taken into consideration in consideration of the fixability of the coloring material to the recording medium. Is preferably further contained in the ink.

As the dispersed resin particles, any resin particles which are solid at a temperature of 35 ° C. or lower and have a good affinity for a non-aqueous solvent (hereinafter sometimes referred to as resin (P)) may be used. Transition point is -5 ° C to 110 ° C or softening point 3
The resin (P) having a temperature of 3 ° C. to 140 ° C. is preferable, and a glass transition point of 10 ° C. to 100 ° C. or a softening point of 38 ° C.
120 ° C., more preferably 15 ° C. glass transition point
８０80 ° C. or a softening point of 38 ° C. to 100 ° C. By using such a resin having a glass transition point or a softening point, the adhesiveness between an image and a recording medium is improved, and in particular, when plate making is performed, the printing durability of the resulting plate material can be significantly improved. it can.

The weight average molecular weight (Mw) of the resin (P) is
Preferably 1 × 10 ³ to 1 × 10 ⁶ , more preferably 5 ×
10 ³ to 8 × 10 ⁵ , more preferably 1 × 10 ^{4 to} 5 × 1
0 ^5.

Specific examples of such a 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), 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 (for example, butadiene-styrene copolymer, isoprene-styrene copolymer, styrene-methacrylate copolymer) Polymer, styrene-acrylate copolymer, etc.), acrylonitrile copolymer, methacrylonitrile copolymer, alkyl vinyl ether copolymer, acrylate ester polymer and copolymer, methacrylate ester polymer and copolymer, Itaconic acid diester polymer and copolymer, anhydrous maleic Acid copolymers, acrylamide copolymers, methacrylamide copolymers, phenolic resins,
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, nitrogen-free heterocycle Copolymers (for example, a heterocycle 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

At this time, the dispersed resin particles used in the ink can be produced by a conventionally known mechanical pulverization method or polymerization granulation method. As a mechanical pulverization method, if necessary, resin particles and a coloring material are mixed, melted, kneaded, and then directly pulverized by a conventionally known pulverizer to obtain fine particles, and a dispersing polymer is used in combination. Examples thereof include a method of dispersing with a machine (for example, a ball mill, a paint shaker, a Keddy mill, and a dyno mill), and a method of dispersing colorant particles 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 methods are described in "Paint Flow and Pigment Dispersion" edited by Kenji Ueki, Kyoritsu Shuppan (1971),
"Solomon, Science of Paint", "Paint and Surface Coat"
ing Theory and Practice ”, Yuji Harazaki“ Coating Engineering ”Asakura Shoten (1971), Yuji Harasaki“ Basic Science of Coatings ”Maki Shoten (1977), etc.

It is also possible to prepare resin particles by a polymerization granulation method and to add a coloring material to the resin particles. As the polymerization granulation method, a conventionally known non-aqueous dispersion polymerization method can be mentioned. Specifically, the latest technology of ultrafine polymer supervised by Soichi Muroi, Chapter 2, CMC Publishing (1991), edited by Koichi Nakamura "Recent development of electrophotographic development systems and toner materials
Practicalization ", Chapter 3, (Nippon Scientific Information Inc., 1985), KEJ Barrett," Dispersion Polymerization in
Organic Media ", John Wiley (1975).

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 × by weight average molecular weight (Mw).
10 ³ to 1 × 10 ⁶ is preferable, and 5 × 10 ⁶ is more preferable.
The range is ^{3 to} 5 × 10 ⁵ .

As a preferred soluble repeating unit of the dispersion polymer used in the present invention, a polymerization component represented by the following general formula (1) can be mentioned.

[0106]

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 alkenyl group having from 32 to 32, preferably represents an alkyl group or alkenyl group having from 10 to 22 carbon atoms, and may be linear or branched. Unsubstituted ones are preferred, but may have substituents. Specifically, decyl group, dodecyl group, tridecyl tomb, tetradecyl group, hexadecyl group, otatadecyl group, eicosanyl group, docosanyl group, decenyl group, dodecenyl group, tridecenyl group, hexadecenyl group, octadecenyl group, linolel group, and the like. .

A ₁ and a ₂ may be the same or different from each other, and are preferably a hydrogen atom, a halogen atom (for example, a chlorine atom, a bromine atom, etc.), a cyano group, and a carbon number of 1 to 3.
Alkyl group (e.g., methyl group, ethyl group, propyl group, etc.), - COO-Z ₁ or -CH ₂ COO-Z ₁ [Z ₁
Is a hydrogen atom or an optionally substituted hydrocarbon group having 22 or less carbon atoms (for example, an alkyl group, an alkenyl group,
An aralkyl group, an alicyclic group, an aryl group, etc.).

Here, Z ₁ specifically represents a hydrocarbon group in addition to a hydrogen atom.
An alkyl group which may be substituted and has 1 to 22 carbon atoms (e.g., methyl, ethyl, propyl, butyl, heptyl, hexyl, octyl, nonyl, decyl, dodecyl, tridecyl, tetradecyl) Group, hexadecyl group, otatadecyl group, eicosanyl group, docosanyl group, 2-chloroethyl group, 2-bromoethyl group, 2
-Cyanoethyl group, 2-methoxycarbonylethyl group,
2-methoxyethyl group, 3-bromopropyl group and the like, an alkenyl group having 4 to 18 carbon atoms which may be substituted (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, linolel group, etc.), substitution having 7 to 12 carbon atoms. Aralkyl groups (e.g., benzyl, phenethyl, 3-phenylpropyl, naphthylmethyl,
2-naphthylethyl group, chlorobenzyl group, bromobenzyl group, methylbenzyl group, ethylbenzyl group, methoxybenzyl group, dimethylbenzyl group, dimethoxybenzyl group, etc.), and optionally substituted alicyclic having 5 to 8 carbon atoms. Groups (for example, cyclohexyl group, 2-cyclohexylethyl group, 2-cyclopentylethyl group, etc.) and optionally substituted aromatic groups having 6 to 12 carbon atoms (for example, phenyl group, naphthyl group, tolyl group, xylyl group) , Propylphenyl, butylphenyl, octylphenyl, dodecylphenyl, methoxyphenyl, ethoxyphenyl, butoxyphenyl, decyloxyphenyl, chlorophenyl, dichlorophenyl, bromophenyl, cyanophenyl, acetylphenyl Group, methoxycarbonyl Group, ethoxycarbonylphenyl group, butoxycarbonylphenyl group, acetamidophenyl group, propionitrile amido phenyl group, such as dodecane white ylamide phenyl group).

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 dispersed polymer is preferably 50% by weight or more, more preferably 60% by weight or more.

Specific examples of these dispersion polymers include:
Examples include the dispersion stabilizing resin (Q-1) used in Examples, and a commercially available product (Solprene 1205, manufactured by Asahi Kasei Corporation) can also be used. The dispersion polymer is preferably added in advance during the polymerization when producing the resin (P) particles as an emulsion (latex) or the like. When the dispersing polymer is used, the amount added is about 0.05 to 4% by weight based on the whole ink.

The dispersed resin particles and the colored particles (or coloring material particles) in the oil-based ink of the present invention may be positively charged or negatively charged electroconductive particles. In order to impart an electric detecting property to these particles, it can be achieved by appropriately utilizing a technique of a developer for wet electrophotography. Specifically, the above-mentioned “Recent development and commercialization of electrophotographic development systems and toner materials”
139-148, edited by the Society of Electrophotography, "Basics and Application of Electrophotographic Technology", 497-505 (Corona Co., 1988), Yuji Harazaki, "Electrophotography" 16 (No. 2), 44 (1977), etc. And the other additives.

For example, metal soaps having 6 to 2 carbon atoms
Fatty acids (e.g., 2-ethylhexanoic acid, 2-ethylcaproic acid, lauric acid, paramitic acid, elaidic acid, linoleic acid, liminolic acid, oleic acid, stearic acid, enanthic acid, naphthenic acid, ethylenediaminetetraacetic acid, etc.), and resins Metal salts such as acid, dialkyl succinic acid, alkyl phthalic acid and alkyl salicylic acid (as metals of metal ions, Na, K, Li, B, Al, Ti, Ca, P
b, Mn, Co, Zn, Mg, Ce, Ag, Cd, Z
r, Cu, Fe, Ba, etc.) (Specific examples; US Pat. No. 34)
No. 11936, No. 3900412, Japanese Patent Publication No. 49-2
7707, JP-A-51-37651, and JP-A-52-38.
No. 937, No. 52-107837, No. 53-1231
No. 38, koto).

As the organic phosphoric acid or salts thereof, mono-, di- or tri-alkyl phosphoric acids or di-alkyl dithiophosphoric acids comprising an alkyl group having 3 to 18 carbon atoms are exemplified in British Patent Nos. 1411739 and 1276363. . Organic sulfonic acids or salts thereof include long-chain aliphatic sulfonic acids, long-chain alkylbenzene sulfonic acids,
Dialkyl sulfosuccinic acid and the like or metal salts thereof are disclosed in JP-B-47-37128 and JP-A-53-123138.
Nos. 51-47437, 50-79640 and 53-30340.

Examples of the amphoteric surfactant include phospholipids such as lecithin and seharin (for example, Japanese Patent Publication No. Sho 51-47046), and β-alanines containing an alkyl group having 8 or more carbon atoms (Japanese Patent Application Laid-Open No. 50-17642, And metal complexes of β-diketones (Japanese Patent Publication No. 49-2).
No. 7707) and a copolymer having a maleic acid half-amide component (for example, JP-B-6-19596 and JP-B-6-19).
595) and the like. These electricity detection materials are
They can be used alone or in combination of two or more.

[0116] The above-mentioned electric detection material is preferably used in an amount of 0.001 to 1.0 part by weight based on 1000 parts by weight of the dispersion medium as the carrier liquid. If desired, various additives may be added, and the upper limit of the total amount of these additives is regulated by the specific electric resistance of the oil-based ink. That is, if the specific electrical resistance of the ink from which the dispersed particles have been removed is lower than 10 ⁹ Ωcm, it becomes difficult to obtain a good quality image. Therefore, it is necessary to control the amount of each additive within this limit. .

In the present invention, a low signal voltage (modulation voltage)
The mechanism that can draw high-resolution dots without bleeding is as follows: colored particles irradiated with light are charged by carrier injection from electrodes under an electric field, or are electrophoresed on the liquid surface by strengthening the charge. It is presumed that ejection occurs after concentration, but details are unknown. However, the present invention is not limited by the above estimation mechanism.

[0118]

EXAMPLES The present invention will be described in detail with reference to examples below, but the contents of the present invention are 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 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 addition of the initiator, 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.).

[0120]

Embedded image

A part of the white dispersion was centrifuged (rotation speed: 1 × 10 ⁴ rpm, rotation time: 60 minutes), and the sedimented 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 by weight), 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 the octadecene-half-maleic acid octadecylamide copolymer into 1 liter of Isopar G.

Next, the ink tank was filled with 2 liters of the oil ink (IK-1) prepared as described above in the ink jet drawing apparatus 2 of the plate making apparatus (see FIGS. 1 and 3). Here, 900 dP shown in FIG.
i, a 64 channel multihead was used. A throwing heater and a stirring blade are provided in the ink tank as ink temperature management means, the ink temperature is set to 30 ° C., and the stirring blade is
The temperature was controlled with a thermostat while rotating at 0 rpm. Here, the stirring blade was also used as a crushing 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 disposed with the ink flow path interposed therebetween. The output signal of the LED light emitting element and the light detecting element are used to dilute the ink (Isoper G) or the concentrated ink (solid ink (IK-1)). The concentration was adjusted by doubling the concentration).

As a plate material, a 0.12 mm-thick aluminum plate subjected to graining and anodic oxidation treatment was mounted on a drum of a plate-making apparatus with a mechanical device provided on a drum. After removing dust from the surface of the plate by suction of the air pump, the ejection head is brought close to the plate to the drawing position, the image data to be printed is transmitted to the image data calculation control unit, and 64 channels are rotated while rotating the drum. By moving the ejection head, an oil-based ink was ejected 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. In addition, at the time of ejection, a bias voltage of 2.5
With a voltage of KV applied, a 100 W white light source (Cold
A pulse voltage (modulation voltage: 375 V, 100 μsec) modulated based on image information is discharged in a state in which the output light of Light HLS2100R (manufactured by HOYA) is irradiated onto each discharge electrode by 64 optical fibers. Applied to the electrodes.
No drawing failure due to greeting was observed at all, and no image deterioration due to a change in the dot diameter 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 (light emission 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 a position close to the drum together with the sub-scanning means.
It was mounted on a plate cylinder of a 66EPZ printing machine and printed.

The obtained printed matter was an extremely clear image without any skipping or blurring in the printed image even after passing through 10,000 sheets. In addition, after supplying Isopar G to the head for 10 minutes after the completion of plate making, cleaning by dropping Isopar G from the head opening, the head is stored in a cover filled with vapor of Isopar G. Good prints could be produced for three months without the need for maintenance work.

Example 2 A circulation pump was used as the stirring means, and the apparatus shown in FIG.
A 600 dpi full line inkjet head of the type shown in FIGS. 6, 8 and 10 was arranged. A pump is used for ink circulation, and ink reservoirs are respectively provided between the pump and the ink inflow path of the ejection head, and between the ink recovery path of the ejection head and the ink tank, and the ink is circulated by a difference in hydrostatic pressure between them. As the ink temperature management means, a heater and the above-mentioned pump were used, the ink temperature was set to 35 ° C., and the temperature was controlled by a thermostat. Here, the circulation pump was also used as a stirring means for preventing precipitation and aggregation.
In addition, 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. As the plate material, the above aluminum plate,
It was similarly mounted on the drum of the plate making apparatus. After removing dust on the surface of the printing plate using a nylon rotating brush, the image data to be printed is transmitted to the image data calculation control unit, and the plate material is drawn by a full line head while transporting the printing plate by the capstan roller. An image was formed by discharging oil-based ink onto the aluminum plate. No defective drawing due to dust was 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, by heating with a heat roller (Teflon seal silicon rubber roller including a 300 W halogen lamp) fixing (pressure: 3 kgf / cm ² (29.4 N / c)
m ² )) The image was strengthened and a printing plate was created.

Further, when printing was performed using the prepressed plate, the printed image was extremely clear without any skipping or blurring even after passing through 10,000 sheets. Further, after cleaning by performing circulation of Isopar G to the head after the end of plate making,
When cleaning was performed by bringing the nonwoven fabric containing Isopar G into contact with the tip of the head, good printed matter could be produced for three months without the need for maintenance work.

Example 3 In place of the aluminum plate of Example 1, a plate material provided with an image-receiving layer capable of being rendered 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 conductive layer prepared as follows using a high-quality paper having a basis weight of 100 g / m ² as a substrate and a polyethylene film on both surfaces of a substrate having a thickness of 20 μm and water-resistant laminated on a paper support having the following composition. Apply the paint for 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 m ² , thereby obtaining a plate material.

Paint for isoelectric layer; carbon black (30
% Aqueous solution) 5.4 parts, clay (50% aqueous solution) 54.6
Parts, SBR latex (solid content 50%, Tg 25 ° C) 3
Six parts and 4 parts of a melamine resin (solid content 80%, Sumiretz Resin SR-613) were mixed, and water was added so that the total solid content was 25% 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 wet-dispersed with a homogenizer (manufactured by Nippon Seiki Co., Ltd.).
For 8 minutes at 6,000 rpm.

[0133]

Embedded image

When fixing was performed by blowing hot air on the plate material, blisters were generated. Therefore, fixing is performed by gradually and continuously increasing the heater used for the hot air or by gradually and continuously decreasing the rotation speed of the drum from a high speed to a low speed without changing the supply power. as a result,
Blisters did not occur, and the printed matter obtained by printing the plate material was a very clear image with no skipping or blurring in the printed image even when the number of sheets passed 5,000.

[0135]

According to the present invention, a large number of clear images can be printed by a high-speed ink-jet recording system which has a high resolution without blur, can be driven stably, is inexpensive, and can be easily formed into a line head. A printing plate that can be printed on multiple sheets can be created.
In addition, a printing plate directly corresponding to digital image data can be stably produced with high image quality, and inexpensive and high-speed lithographic printing can be performed.

[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 schematic cross-sectional view of an example of a discharge head provided in an ink jet drawing apparatus used in the present invention, in the vicinity of a discharge unit.

FIG. 5 is a schematic front view of the vicinity of a discharge unit in FIG. 4;

FIG. 6 is a schematic configuration diagram illustrating a main part of an example of an ejection head provided in an inkjet drawing apparatus used in the present invention.

FIG. 7 is a schematic configuration diagram of a head obtained by removing a regulating plate from the ejection head of FIG.

FIG. 8 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.

[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 plate) 10 dust removing device 11 drum 12 capstan roller 13 grounding means 21 Image data calculation control unit 22 Discharge head 22a Discharge slit 22b Discharge electrode 23 Electro-optic modulator 24 Ink supply unit 25 Ink tank 26 Ink supply device 27 Stirring device 28 Ink temperature management unit 29 Ink density control unit 30 Encoder 31 Head separation unit 32 Head sub-scanning means 33 First insulating base material 34 Second insulating base material 35 Slope view of second insulating base material 36 Top view of second insulating base material 37 Ink flow path 38 Ink recovery Road 39 Packing 40 Groove 41 Head body 42, 42 'Meniscus regulating plate 43 Upper 56 guide projection 61 signal power of ink grooves 44 partition wall 45, 45 'discharge portion 46 partition wall 47 partition wall tip 50, 50' the support members 51, 51 'groove 52 partition wall 53 upper portion 54 rectangular portion 55 partition wall

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuo Ishii 4,000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Inside Fujisha Shin Film Co., Ltd. In-house F-term (reference) 2C056 EA05 EA28 EB07 EB30 EC21 EC29 FA10 FA13 FB01 FB09 HA05 2H084 AA25 AE05 BB01 BB16 CC05 2H086 BA51 BA54 BA60 4J039 AD06 AD08 AD10 AE11 BC02 BC03 BC05 BE01 BE07 BE07 EA24 GA04

Claims (20)

[Claims] 1. A plate making method for forming an image directly on a plate material based on a signal of image data, fixing the image, and creating a printing plate to be used for lithographic printing. A modulated voltage modulated based on a signal of the image data is supplied to an ejection head arranged opposite to a material, and a modulated voltage is modulated based on a signal of the image data in a state where an electrostatic field is formed on the ejection head and the insulating ink is irradiated with light. A plate-making method, wherein an image is formed directly on the plate material by applying the insulating ink from the discharge head by applying the ink to a head. 2. The method according to claim 1, wherein the insulating ink has a specific electric resistance value of 1.
The plate making method according to claim 1, wherein the colored particles which are solid at least at room temperature are dispersed in a non-aqueous solvent having a resistivity of not less than 0 ⁹ Ωcm and not more than 3.5. 3. The plate making method according to claim 1, wherein the light includes a wavelength that is absorbed by the insulating ink. 4. A plate making apparatus comprising an image forming means for forming an image directly on a plate material based on a signal of image data, wherein the plate material on which the image is formed is used as a printing plate for lithographic printing. A discharge head that is disposed opposite to the plate material and that insulates the insulating ink onto the plate material, and that a bias voltage is applied to form an electrostatic field in the discharge head, and the discharge head is modulated based on a signal of the image data. A voltage application unit for applying a modulation voltage; and a light irradiating unit for irradiating the insulating ink with light, comprising: an ink jet drawing apparatus, wherein the voltage applying unit forms an electrostatic field in the ejection head, In a state where the insulating ink is irradiated with the light by the light irradiating means, further, the modulation voltage is applied to the ejection head by the voltage applying means, whereby the insulation is performed. Plate making apparatus characterized by an ink was allowed to fly to the plate material from the ejection head forms an image directly on the plate material. 5. The method according to claim 1, wherein the insulating ink has a specific electric resistance value of 1.
5. The plate making apparatus according to claim 4, wherein solid color particles are dispersed at least at room temperature in a non-aqueous solvent having a resistivity of not less than 0 ⁹ Ωcm and not more than 3.5. 6. The plate making method according to claim 4, wherein the light irradiating unit irradiates light having a wavelength absorbed by the insulating ink. 7. The plate making apparatus according to claim 4, further comprising an image fixing unit for fixing an image formed by said image forming unit. 8. The apparatus according to claim 4, further comprising dust removing means for removing dust existing on the surface of the printing plate before and / or during drawing on the printing plate. Plate making equipment. 9. The plate making apparatus according to claim 4, wherein the main scanning is performed by rotating a drum on which the plate is mounted when drawing on the plate. 10. The sub-scan according to claim 9, wherein the discharge head has a single head or a multi-head shorter than the width of the plate material, and performs sub-scanning by moving the discharge head in the axial direction of the drum. Plate making equipment. 11. The plate-making apparatus according to claim 4, 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. . 12. The printing apparatus according to claim 1, wherein the ejection head has a single head or a multi-head shorter than the width of the plate material, and performs main scanning by moving the ejection head in a direction orthogonal to a traveling direction of the plate material. Item 12. A plate making apparatus according to item 11. 13. The printing apparatus according to claim 9, wherein the discharge unit has a full line head having a length substantially equal to a width of the plate material.
2. The plate making apparatus according to 1. 14. The plate making apparatus according to claim 4, wherein said ink jet drawing apparatus further comprises an ink supply means for supplying said insulating ink to said discharge head. 15. The plate making apparatus according to claim 14, wherein the ink jet drawing apparatus further includes an ink recovery unit that recovers excess ink from the discharge head, and performs ink circulation. 16. The plate making apparatus according to claim 4, wherein said ink jet drawing apparatus further comprises a stirring means for stirring said insulating ink in an ink tank storing said insulating ink. . 17. The ink-jet drawing apparatus according to claim 4, further comprising an ink temperature management unit that manages a temperature of the insulating ink in an ink tank that stores the insulating ink. The plate making device described in the above. 18. The plate making apparatus according to claim 4, wherein said ink jet drawing apparatus further comprises an ink density control means for controlling the density of said insulating ink. 19. The ink jet drawing apparatus further comprises a separation / contact means for separating / contacting the discharge head from / to the plate material, and separating / contacting the discharge head from the plate material except during drawing. 19. The plate making apparatus according to any one of items 4 to 18. 20. A cleaning device for cleaning the discharge section at least after the completion of plate making.
20. A plate-making apparatus according to any one of claims 19 to 19.