JP2002292819A - On-machine drawing lithographic printing method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-machine drawing lithographic printing method by which a large number of printed matters showing a clear-cut image can be printed rapidly and at a low cost, with the capability of dealing with digital image data as well as an on-machine drawing lithographic printing device. SOLUTION: This on-machine drawing lithographic printing method comprises the steps of mounting a printing plate material on a plate cylinder of a printer, creating a printing plate by forming an image directly on the printing plate material by an ink jet process to discharge an oil ink from a recording head using an electrostatic field based on a signal of image data and further and performing a lithographic printing process in succession with the use of the printing plate as it is. In this method, an agglomerate or a sediment of the oil ink is redispersed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-press lithographic printing method and an on-press lithographic printing apparatus for performing digital plate making with an oil-based ink and then performing printing on a printing press. The present invention relates to redistribution of ink for improving plate making quality and printing quality.

[0002]

2. Description of the Related Art In lithographic printing, printing is performed by providing an ink receptive area and an ink repellent area on the surface of a printing plate corresponding to an image original, and attaching printing ink to the ink receiving area. Normally, 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 fountain solution.

Recording an image on a printing original plate (plate material) (plate making)
Prints an image original in analog or digital form on a silver halide photographic film, exposes a diazo resin or photopolymerizable photopolymer photosensitive material through it, and removes non-image areas mainly by elution using an alkaline solution. This is a common method.

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

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

Further, as a means for improving the efficiency of the printing process, there is a system for performing image drawing on a printing press. Although there is a method using the above laser, it is expensive and requires a large device. Therefore, systems using the inkjet method, which is an inexpensive and compact drawing apparatus, have been tried.

In Japanese Patent Application Laid-Open No. 4-97848, a plate drum having a hydrophilic or lipophilic surface is provided in place of the conventional plate cylinder, and an lipophilic or hydrophilic image is formed thereon by an ink jet method. A method is disclosed for removing the image after forming and printing, and cleaning. However, in this method, it is difficult to achieve both removal of a printed image (that is, ease of cleaning) and printing durability. Further, in order to form a print image having high printing durability on a plate cylinder, it is necessary to use an ink containing a relatively high concentration of resin. As a result, the adhesion of the resin is likely to occur, and the stability of ink ejection is reduced. As a result, it becomes difficult to obtain a good image.

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

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

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object the first object of the present invention is to provide a digitally compatible on-press drawing lithographic printing method which does not require development processing, and On-press lithographic printing method capable of providing a re-dispersion means to an on-press lithographic printing apparatus, preventing aggregation and sedimentation of oil-based ink particles, and supplying ink always kept in a normal dispersion state to a recording head, and An on-press lithographic printing apparatus is provided. Secondly, it is an object of the present invention to provide an on-press lithographic printing method and an on-press lithographic printing apparatus capable of printing a large number of clear and high-quality images using an inexpensive apparatus and a simple method. As a result, clogging of the pipe and clogging of the recording head can be prevented, and an unstable state of ink ejection can be avoided to prevent degradation in drawing image quality.

[0011]

To achieve the above object, an invention of an on-press lithographic printing method according to the first aspect of the present invention is to mount a plate material on a plate cylinder of a printing press, and to print an image on a stationary plate material. By using an ink jet method in which an oil-based ink is ejected from a recording head by using an electrostatic field based on a data signal, an image is directly formed to create a printing plate, and lithographic printing is subsequently performed using the printing plate in that state. The on-press lithographic printing method is characterized in that at least aggregates and / or sediments of the oil-based ink particles, which are generated due to, for example, stationary flow of the ink, are redispersed. According to this configuration, since the aggregates and sediments of the oil-based ink particles are redispersed, the aggregation and sedimentation of the oil-based ink particles can be prevented, and the ejection state becomes stable. According to the second aspect of the present invention, in the on-press lithographic printing method according to the first aspect, the oil-based ink is a non-aqueous solvent having a specific electric resistance of 10 ⁹ Ωcm or more and a dielectric constant of 3.5 or less. In addition, it is characterized in that at least room temperature, solid and hydrophobic resin particles are dispersed. According to the third aspect of the present invention, the oil-based ink is discharged using an electrostatic field as an image forming means for directly forming an image on a plate material mounted on a plate cylinder of a printing press based on a signal of image data. An on-press drawing printing apparatus comprising: an ink jet drawing apparatus having a recording head for performing printing; and a lithographic printing means for performing lithographic printing on a printing plate on which an image is formed by the image forming means. And a means for redispersing aggregates and / or sediments of the oil-based ink particles generated by the method. According to this configuration, since the means for re-dispersing aggregates and / or sediments of oil-based ink particles is provided, the ink can be returned to a well-dispersed state. According to a fourth aspect of the present invention, in the on-press printing apparatus according to the third aspect, the re-dispersion unit is provided immediately before an ink ejection unit of the recording head. According to this configuration, since the re-dispersion unit is particularly arranged immediately before the recording head, ink in a normal dispersion state immediately after the re-dispersion unit can be supplied to the recording head. According to a fifth aspect of the present invention, in the on-press printing apparatus according to the third or fourth aspect, the re-dispersion is performed at least before and / or simultaneously with the flow of the ink. . According to this configuration, by operating the re-dispersion means in particular prior to the ink flow, a good re-dispersed ink flow can be obtained. According to a sixth aspect of the present invention, in the on-press drawing printing apparatus according to any one of the third to fifth aspects, the re-dispersion means includes any one of stirring, dispersion, mixing, and jet flow. It is characterized by being performed by the action including. According to the seventh aspect of the present invention, in the on-press drawing printing apparatus according to any one of the third to sixth aspects, the stirring, dispersing, mixing, and jetting operations are applied singly or in a plurality or in multiples. It is characterized by doing. According to this configuration, the re-dispersion means is constituted by a combination of the stirring, the dispersion, the mixing, and the jet action, so that the re-dispersion can be performed more favorably.

According to an eighth aspect of the present invention, in the on-press drawing printing apparatus according to any one of the third to seventh aspects, the stirring, dispersing, mixing, and jetting operations are performed periodically. Or continuously. According to this configuration, stirring, dispersion, mixing, and jet action are performed as needed.
By functioning regularly or continuously, a good ink state can be maintained. According to the ninth aspect of the present invention, in the on-press drawing printing apparatus according to any one of the third to eighth aspects, the means for redispersing the aggregates and / or sediments of the ink particles includes: It is characterized by being interchangeable as a cartridge type. According to this configuration, maintenance can be facilitated by making the re-distribution means replaceable as a cartridge type. According to a tenth aspect of the present invention, in the on-press drawing lithographic printing apparatus according to any one of the third to ninth aspects, the oil-based ink has a specific electric resistance of 109 Ωc.
It is characterized in that solid and hydrophobic resin particles are dispersed at least at room temperature in a non-aqueous solvent having a dielectric constant of at least m and a dielectric constant of at most 3.5. According to the eleventh aspect of the present invention, in the on-press drawing lithographic printing apparatus according to any one of the third to tenth aspects, the image forming means includes the ink fixing device. It is characterized by: According to the invention of claim 12, according to claim 3,
12. The on-press lithographic printing apparatus according to claim 1, wherein the image forming unit removes dust existing on the plate material surface before and / or during drawing on the plate material. It is characterized by having dust removing means. According to the invention of claim 13, according to claims 3 to 12,
5. The on-press lithographic printing apparatus according to claim 1, wherein, when drawing on the plate material, the image forming unit performs main scanning by rotating a plate cylinder on which the plate material is mounted. . According to a fourteenth aspect of the present invention, in the on-press lithographic printing apparatus according to the thirteenth aspect, the recording head comprises a single-channel head or a multi-channel head, and the recording head is used when drawing on the plate material. Performs sub-scanning by moving in the direction parallel to the axis of the plate cylinder. According to a fifteenth aspect of the present invention, in the on-press drawing lithographic printing apparatus according to the thirteenth aspect, the recording head comprises a full line head having substantially the same length as the width of the plate cylinder. I have. According to a sixteenth aspect of the present invention, in the on-press lithographic printing apparatus according to any one of the third to fifteenth aspects, the ink jet drawing apparatus supplies an ink to the recording head. It is characterized by having means. According to the seventeenth aspect of the present invention, in the on-press lithographic printing apparatus according to the sixteenth aspect,
An ink collecting means for collecting ink from the recording head is provided, and the ink is circulated by the ink supply means and the ink collecting means. According to the eighteenth aspect of the present invention, in the on-press lithographic printing apparatus according to any one of the third to fifteenth aspects, an ink stirring means is provided in an ink tank for storing the oil-based ink. It is characterized by: According to the nineteenth aspect, any one of the third to eighteenth aspects is provided.
The on-press lithographic printing apparatus according to the item, further comprising an ink temperature control means for controlling the temperature of the ink in the ink tank storing the oil-based ink. According to a twentieth aspect of the present invention, in the on-press lithographic printing apparatus according to any one of the third to nineteenth aspects, there is provided an ink density control means for controlling an ink density of the ink. It is characterized by: Claim 2
According to the invention as set forth in claim 1, any one of claims 3 to 20
Item In the on-press drawing lithographic printing apparatus, wherein the inkjet drawing apparatus brings the recording head close to the plate cylinder when drawing on the plate material, and moves the recording head to the plate except when drawing on the plate material. It is characterized by comprising a recording head separation / contact means for separating from the body. According to a twenty-second aspect of the present invention, in the on-press lithographic printing apparatus according to any one of the third to twenty-first aspects, the image forming means performs cleaning of the recording head at least after the completion of plate making. It is characterized by having a recording head cleaning means. According to the twenty-third aspect of the present invention, the third aspect is provided.
23. The on-press lithographic printing apparatus according to claim 22, wherein said lithographic printing means includes paper dust removing means for removing paper dust generated during lithographic printing.

[0013]

Embodiments of the present invention will be described below in detail. The present invention is characterized in that an image is formed on a plate material (printing original plate) provided on a plate cylinder of a printing press by an ink jet method in which oily ink is discharged from a recording head by an electrostatic field.

The ink jet method according to the present invention uses a PC
In the ink jet method, an ink having high resistance in which solid and hydrophobic resin particles are dispersed at least at room temperature in an insulating solvent is used. By applying a strong electric field at the discharge position, an aggregate of resin particles is formed at the discharge position, and the aggregate is discharged from the discharge position by electrostatic means. In this way, the resin particles are ejected as an aggregate having a high concentration, and the thickness of the printed dot is sufficiently obtained. As a result, an image of the aggregated resin particles having sufficient printing durability is formed on the plate material as the recording medium. In addition, in the present inkjet method, the size of the ejected ink droplet is determined by the size of the tip of the ejection electrode or the electric field forming conditions, and a small ink droplet can be obtained without reducing the ejection nozzle diameter or the slit width. The dot diameter on the plate material can be controlled by controlling the electric field forming conditions. Therefore, according to the present invention, it is possible to control a print-resistant minute image without causing a problem of ink clogging of the head, and it is possible to print a large number of clear images.

An example of the configuration of an on-press lithographic printing apparatus used for carrying out the lithographic printing method of the present invention will be described below.
FIG. 1 is an overall configuration diagram of an on-press drawing single-color single-sided lithographic printing apparatus. FIG. 2 is a schematic configuration example of a drawing unit including a control unit, an ink supply unit, and a head separation / contact mechanism of the on-board drawing planographic printing apparatus. FIG. 3 is a configuration diagram of an ink supply device having an ink recovery function, and FIGS.
This is for describing an ink jet recording apparatus included in the on-press lithographic printing apparatus. Further, FIG.
1 is an overall configuration example of an on-press 4-color single-sided lithographic printing apparatus according to the present invention.

First, the printing process according to the present invention will be described with reference to the overall configuration diagram of an on-press drawing single-color single-sided lithographic printing press shown in FIG. As shown in FIG. 1, an on-press lithographic printing apparatus 1 (hereinafter, also simply referred to as “printing apparatus”) includes a plate cylinder 1.
1, having one blanket cylinder 12 and one impression cylinder 13,
At least when performing lithographic printing, a blanket cylinder 12 for transfer is arranged so as to press against the plate cylinder 11, and the blanket cylinder 12 is used to transfer the printing ink image transferred to the blanket cylinder 12 to the printing paper P. The impression cylinder 13 is arranged so as to be in pressure contact with the impression cylinder 13.

The plate cylinder 11 is usually made of metal, and its surface is plated with, for example, chromium in order to enhance abrasion resistance, but may have a heat insulating material on its surface as described later. . On the other hand, the plate cylinder 11 is preferably grounded because it becomes a counter electrode of the recording head electrode in the electrostatic field discharge.
Further, 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 plate cylinder from the conductive layer. Further, even when the heat insulating material is provided on the plate cylinder as described above, the drawing is facilitated by providing the 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 printing apparatus 1 has an ink jet recording apparatus (ink jet drawing apparatus) 2, which is mounted on the plate cylinder 11 in accordance with the image data sent from the image data operation control unit 21. An oil-based ink is discharged onto the plate material 9 to form an image.

Further, the printing apparatus 1 is provided with a dampening water supply device 3 for supplying dampening water to a hydrophilic portion (non-image portion) on the printing plate 9. FIG. 1 shows a Molton water supply system as a representative example of the dampening water supply device 3, but other known devices, such as a synflo water supply system and a continuous water supply system, can be used as the dampening water supply device 3. Further, the printing device 1
The printing apparatus includes a printing ink supply device 4 and a fixing device 5 for strengthening an oil-based ink image drawn on the plate material 9. If necessary, a plate surface desensitizing device 6 may be provided for the purpose of enhancing the hydrophilicity of the surface of the plate material 9. Further, the printing apparatus 1 has a plate material surface dust removing means 10 for removing dust existing on the plate material surface before and / or during drawing on the plate material. Accordingly, it is possible to effectively prevent the ink from adhering to the plate material by transmitting dust that has entered between the head and the plate material during plate making, and to obtain a good plate-making. As the dust removing means, in addition to the known non-contact methods such as suction removal, blowing removal, and electrostatic removal, a contact method using a brush, a roller, or the like can be used. Or a combination thereof. In this case, an air pump usually used for a paper feeding device can be used for this purpose.

Further, an automatic plate feeding device 7 for automatically supplying a plate material 9 to be printed to the plate cylinder 11 and an automatic plate discharging device 8 for automatically removing the plate material 9 after printing from the plate cylinder 11. May be installed. As a printing press having this device, which is known as an auxiliary device of a printing press, for example, Hamada VS3
4A, B452A (Hamada Printing Machinery Co., Ltd.), Toko 8000 PFA (Tokyo Aviation Instruments), Ryobi 32
00ACD, 3200 PFA (Ryobi Magicjik Co., Ltd.), AMSIS Multi 5150FA (Nippon Am Co., Ltd.), Oliver 266EPZ (Sakurai Graphic Systems Co., Ltd.), Shinohara 66IV / IVP (Shinohara Shoji Co., Ltd.) and the like. Further, a blanket cleaning device 14 and an impression cylinder cleaning device 14 'may be provided. By using these devices 7, 8, 14, and 14 ', the printing operation becomes simpler and the printing time is shortened, so that the effect of the present invention can be further enhanced. In addition, impression cylinder 1
A paper dust generation preventing device (paper dust removing means) 15 may be provided in the vicinity of 3 to prevent paper dust from adhering to the plate material. As the paper dust generation preventing device 15, a method such as humidity control, suction by air or electrostatic force, or the like can be used.

An image data arithmetic control unit 21 receives image data from an image scanner, a magnetic disk device, an image data transmission device, etc., performs color separation, and has an appropriate number of pixels and gradation for the separated data. Divide into numbers. Further, in order to draw an oil-based ink image as a halftone dot using an ink jet recording head 22 (see FIG. 2, which will be described in detail later) as a recording head of the ink jet recording apparatus 2, a dot area ratio is also calculated. .

As will be described later, the image data calculation control unit 21 controls the movement of the ink jet recording head 22 and the ejection timing of the oil-based ink, and if necessary, the plate cylinder 11, blanket cylinder 12, impression cylinder 13 , Etc., is also controlled.

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

First, the plate material 9 is mounted on the plate cylinder 11 by using the automatic plate feeding device 7. At this time, the plate material is closely fixed on the plate cylinder by a known method such as a plate head / butt holding device, an air suction device, or an electrostatic method. Inkjet recording device 2
Can be prevented from being damaged due to contact with the object. Further, a means for bringing the plate material into close contact with the plate cylinder only around the drawing position of the ink jet recording apparatus is provided, and this is applied at least when drawing is performed, thereby preventing the plate material from contacting the ink jet recording apparatus. You can also. In particular,
For example, there is a method of arranging a pressing roller upstream and downstream of the plate cylinder drawing position. In addition, by providing a means for preventing the bottom of the plate from contacting the ink supply roller in the process of fixing the plate, it is possible to prevent the plate surface from being stained and to reduce waste paper. Specifically, a pressing roller, a guide, electrostatic attraction, or the like is effective.

Image data from a magnetic disk device or the like
The image data calculation control unit 21 is provided with the image data calculation control unit 21 and calculates the ejection position of the oil-based ink and the halftone dot area ratio at that position in accordance with the input image data. These operation data are temporarily stored in the buffer. The image data calculation control unit 21 rotates the plate cylinder 11 to bring the recording head 22 closer to a position close to the plate cylinder 11 by a head separation / contact device (recording head separation / contact means) 31. The distance between the recording head 22 and the surface of the plate material 9 on the plate cylinder 11 is controlled by a mechanical distance control such as an abutment roller or the control of a head separating device by a signal from an optical distance detector during drawing. It is kept at a predetermined distance. By this distance control, the dot diameter does not become uneven due to the lifting of the plate material, and the dot diameter does not change even when vibration is applied to the printing press, in particular.
Good plate making can be obtained.

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

Next, in order to protect the recording head 22,
The recording head 22 is retracted away from a position close to the plate cylinder 11. At this time, the recording head 22 and the head sub-scanning means 32 may be separated and connected together, or the recording head 22 and the ink supply unit 24 and all the head sub-scanning means 32 may be separated and connected together. You can also touch. In addition, the fixing device 5 and the dust removing unit 10 are also provided with separating / contacting means together with the recording head 22, the ink supply unit 24, and the head sub-scanning means 32 so that they can be retracted.

This separation / contact means operates so as to separate the recording head from the plate cylinder by at least 500 μm except during drawing. The detachment operation may be of a sliding type, or the 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 head during non-drawing in this manner, the head can be protected from physical damage or contamination, and a longer life can be achieved.

Further, the formed oil-based ink image is reinforced by heating or the like in the fixing device 5. As the fixing means for the ink, known means such as heat fixing, solvent fixing, and flash exposure fixing can be used. In the heat fixing, irradiation with an infrared lamp, a halogen lamp, a xenon flash lamp, hot air fixing using a heater, and heat roll fixing are generally used. In this case, in order to enhance the fixing property, the plate cylinder is heated, the plate material is pre-heated, drawing is performed while applying hot air, the plate cylinder is coated with a heat insulating material, and the plate cylinder is only fixed during fixing. It is effective to take measures such as separating the plate material from the plate and heating only the plate material alone or in combination. Flash fixing using a xenon lamp or the like is known as a method for fixing electrophotographic toner, and has an advantage that fixing can be performed in a short time. Methanol for solvent fixation,
A solvent capable of dissolving the resin component in the ink, such as ethyl acetate, is sprayed, and excess solvent vapor is collected. Note that at least in the process from the formation of the oil-based ink image by the recording head 22 to the fixing by the fixing device 5, the dampening water supply device 3, the printing ink supply device 4, and the blanket cylinder 12 apply the plate material 9 on the plate cylinder. Desirably, it is kept out of contact.

The printing process after the printing plate is formed is the same as the known lithographic printing method. That is, printing ink and dampening water are applied to the plate material 9 on which the oil-based ink image is drawn to form a print image, and the print ink image is transferred onto the blanket cylinder 12 rotating with the plate cylinder 11, Next, printing of one color is performed by transferring the printing ink image on the blanket cylinder 12 onto the printing paper P passing between the blanket cylinder 12 and the impression cylinder 13. Plate 9 after printing
Is removed from the plate cylinder 11 by the automatic plate discharging device 8, the blanket on the blanket cylinder 12 is cleaned by the blanket cleaning device 14, and the next printing is possible.

Next, the ink jet recording apparatus 2 will be described in detail. As shown in FIG. 2, the drawing unit used in the lithographic printing apparatus includes an inkjet recording device 2,
An ink supply unit 24 is provided. The ink supply unit 24 further includes an ink tank 25, an ink supply device 26, and an ink density control unit 29. The ink tank 25 includes an ink stirring unit 27 and an ink temperature management unit (ink temperature control unit) 28. . The ink may be circulated in the recording head as shown in FIG. In this case, the ink supply unit 24 also has a recovery circulation function. Ink stirring means 2
Reference numeral 7 denotes a re-dispersion means for re-dispersing the ink by a stirring action or the like, which suppresses precipitation and aggregation of the solid components of the ink, and reduces the necessity of cleaning the ink tank. As the ink stirring means for re-dispersion, a rotary wing, an ultrasonic vibrator, and a circulating pump can be used, and these are used or in combination. The details will be described later. The ink temperature management unit 28 is arranged so that a high-quality image can be stably formed without changing the physical properties of the ink due to a change in ambient temperature and without changing the dot diameter. As the ink temperature management means, a heating element or a cooling element such as a heater or a Peltier element is arranged in an ink tank together with a stirring means so as to keep the temperature distribution in the tank constant, and controlled by a temperature sensor such as a thermostat. A known method such as the above method can be used. The temperature of the ink in the ink tank is desirably from 15 ° C to 60 ° C, more preferably from 20 ° C to 50 ° C. Further, the stirring means for keeping the temperature distribution in the tank constant may be shared with the ink stirring means for suppressing the precipitation and aggregation of the solid components of the ink.

FIG. 3 is a configuration diagram of the ink supply device 24 having an ink recovery function. As shown in the figure, the ink supply device 24 has a valve 61, a pump 26 for supplying ink to the head 22, an ink concentration control unit 29, and a circulating / recovering device for circulating and collecting ink from the head. It has a pump 26 'and a valve 61'. The ejection head 2
By arranging a filtering means such as a filter immediately before step 2, it is possible to supply cleaner ink that does not contain paper fibers or dust to the recording head 22.

Further, the printing apparatus has an ink density control means 29 for performing high-quality drawing. Accordingly, it is possible to effectively suppress the occurrence of bleeding on the plate due to a decrease in the solid content in the ink, the jumping or blurring of the printed image, or the change in the dot diameter on the plate due to the increase in the solid content. The ink density is measured by optical detection, physical property measurement such as conductivity measurement, clay measurement, or the like, or management based on the number of drawn images. When performing management by physical property measurement, an optical detector, a conductivity measuring instrument, and a clay measuring instrument are provided alone or in combination in the ink tank or ink flow path, and the ink concentration is determined by the output signal. Control and also
When performing management based on the number of drawn sheets, the supply of liquid from a replenishment concentrated ink tank or a diluted ink carrier tank (not shown) to the ink tank 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,
1. In addition to moving the head by the head sub-scanning means 32, a timing pulse from the encoder 30 installed on the plate cylinder is fetched, and the head is driven according to the timing pulse. Thereby, the positional accuracy in the sub-scanning direction can be improved. In addition, the position accuracy in the sub-scanning direction can be enhanced by using a high-precision driving unit different from the driving unit during printing when driving the plate cylinder when performing drawing by the ink jet recording apparatus. In this case, it is desirable to mechanically separate the blanket cylinder, the impression cylinder, and the like, and to drive only the plate cylinder. Specifically, for example, there is a method in which the output from a high-precision motor is reduced by a high-precision gear or a steel belt or the like, and only the plate cylinder is driven. When performing high-quality drawing, such means alone,
Alternatively, use in combination.

Next, the recording head will be described with reference to FIGS. However, the contents of the present invention are not limited to the following embodiments.

FIGS. 4 and 5 show an example of a head provided in an ink jet recording apparatus. The head 22 includes an upper unit 221 and a lower unit 22 made of an insulating base material.
2 and a discharge slit 22a at the tip, and a discharge electrode 22b is provided in the slit.
Are arranged, and the ink 23 supplied from the ink supply device is provided.
Is filled in the slit. As the insulating substrate, for example, plastic, glass, ceramics, etc. can be applied. The discharge electrode 22b is formed by vacuum deposition, sputtering, or electroless plating of a conductive material such as aluminum, nickel, chromium, gold, or platinum on a lower unit 222 made of an insulating base material, and then a photoresist is formed thereon. Is applied, the photoresist is exposed through a mask having a predetermined electrode pattern, and is developed to form a photoresist pattern of the discharge electrode 22b. Then, a method of etching or a method of mechanically removing the photoresist pattern is used. It is formed by a known method such as a combined method.

In the head 22, a voltage is applied to the ejection electrode 22b according to a digital signal of an image pattern.
As shown in FIG. 4, a plate cylinder 11 serving as a counter electrode is provided so as to face the discharge electrode 22b, and a plate material 9 is provided on the plate cylinder 11 serving as a counter electrode. By applying a voltage, the discharge electrode 22b and the plate cylinder 11 serving as a counter electrode are formed.
A circuit is formed between them, and the oil-based ink 23 is ejected from the ejection slit 22a of the head 22 to form an image on the plate material 9 provided on the plate cylinder 11 serving as a counter electrode.

It is preferable that the width of the discharge electrode 22b is as narrow as possible in order to form a high quality image. Specific numerical values vary depending on conditions such as applied voltage and ink physical properties, but are usually used in a range of a tip width of 5 to 100 μm. For example, a discharge electrode 22b having a 20 μm wide tip is used, the distance between the discharge electrode 22b and the plate cylinder 11 serving as a counter electrode is set to 1.0 mm, and a voltage of 3 kV is applied between the electrodes.
A dot of 40 μm can be formed on the plate material 9 by applying a voltage of 1 millisecond.

FIGS. 6 and 7 are a schematic cross-sectional view and a schematic front view, respectively, showing the vicinity of the ink ejection portion of another recording head. In the figure, reference numeral 22 denotes a recording head, and the recording head 22 has a first insulating base material 33 having a gradually decreasing shape. A second insulating substrate 34 is provided on the first insulating substrate 33 so as to be spaced apart and opposed to the first insulating substrate 33, and a slope portion 35 is formed at the tip of the second insulating substrate 34. The first and second insulating substrates are made of, for example, plastic, glass, ceramics, or the like. An upper surface 36 that forms an acute angle with the slope 35 of the second insulating base 34 has
A plurality of ejection electrodes 22b are provided as means for forming an electrostatic field in the ejection section. 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. The first
An ink inflow path 37 is formed between the second insulating base material 33 and the second insulating base material 33 as a means for supplying the ink 23 to the ejection portion. 38 are formed. The ejection electrode 22b is a second electrode.
A conductive material such as aluminum, nickel, chromium, gold, or platinum is formed on the insulating base material 34 by a known method as described above. The individual electrodes 22b are configured to be electrically insulated from each other.

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

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

When a uniform ink flow on the discharge section is required, a groove 40 may be provided between the discharge section and the ink recovery path. FIG. 7 is a schematic front view showing the vicinity of the ink ejection portion of the recording head.
A plurality of grooves 40 are provided toward 8. This groove 4
A plurality of inks 0 are arranged in the direction in which the ejection electrodes 22b are arranged, and a certain amount of ink near the tip of the ejection electrode is guided from the opening on the ejection electrode 22b side by a capillary force according to the opening diameter. Is discharged to the ink recovery path 38. For this reason, it has a function of forming an ink flow having a constant liquid thickness near the tip of the discharge electrode. The shape of the groove 40 may be any range as long as the capillary force acts, and particularly preferably, the width is 10 to 200 μm and the depth is 10 to 300 μm.
It is in the range of μm. Further, a 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 in order to form a high quality image. Specific numerical values vary depending on conditions such as applied voltage and ink physical properties, but are usually used in a range of a tip width of 5 to 100 μm.

FIGS. 8 and 9 show other examples of the recording head used to carry out the present invention. FIG. 8 is a schematic diagram showing only a part of the head for explanation. As shown in FIG. 8, the recording head 22 has a head body 4 made of an insulating material such as plastic, ceramic, or glass.
1 and meniscus regulating plates 42 and 42 '. In the figure, 2
Reference numeral 2b denotes an ejection electrode for applying a voltage to form an electrostatic field in the ejection portion. Further, the control plates 42, 42 '
The head main body will be described in detail with reference to FIG.

The head main body 41 is provided with a plurality of ink grooves 43 for circulating ink perpendicular to the edge of the head main body. The shape of the ink groove 43 may be set in a range where the capillary force acts so that a uniform ink flow can be formed, and a particularly desirable width is 10 to 200 μm.
The depth is from 10 to 300 μm. The ejection electrode 22b is provided inside the ink groove 43. This discharge electrode 22
b is formed in the ink groove 43 by using a conductive material such as aluminum, nickel, chromium, gold, and platinum on the head body 40 made of an insulating material by a known method similar to that of the above-described apparatus embodiment. It may be arranged on the entire surface or may be formed only on a part. The discharge electrodes are electrically isolated. The two adjacent ink grooves form one cell, and the ejection portion 4 is provided at the tip of the partition wall 44 at the center thereof.
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. 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. The tip of the discharge section may be slightly chamfered, such as 45 '. Although only two cells are shown in the figure,
The cells are partitioned by a partition wall 46, and the front end portion 47 is chamfered so as to be retracted from the discharge portions 45 and 45 '. Ink is supplied to the head from an I direction through an ink groove by an ink supply unit of an ink supply device (not shown) to supply ink to a discharge unit. Further, surplus ink is collected in the O direction by an ink collecting unit (not shown), and as a result, fresh ink is always supplied to the ejection unit. In this state, ink is ejected from the ejection unit by applying a voltage to the ejection electrode according to image information to a plate cylinder (not shown) holding a plate material on the surface thereof, which is provided to face the ejection unit. An image is formed on the plate material.

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

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

The above-described head 22 shown in FIGS. 4 to 10 can include a maintenance device such as a recording head cleaning unit if necessary. For example, when the pause state continues or when a problem occurs in image quality, the print head tip is wiped with a flexible brush, brush, cloth, or the like, circulates only the ink solvent, supplies only the ink solvent, Alternatively, a single means such as suctioning the discharge part while circulating,
Alternatively, a good drawing state can be maintained by performing the combination. In order to prevent the ink from sticking, it is also effective to cool the head and suppress evaporation of the ink solvent.
If the dirt is further severe, the ink is forcibly sucked from the ejection section, or the air, ink,
Alternatively, it is also effective to apply a jet of an ink solvent, or to apply ultrasonic waves in a state where the head is immersed in the ink solvent, and these methods can be used alone or in combination.

Next, an on-press drawing multicolor single-sided lithographic printing apparatus will be described as a specific example of the present invention. FIG. 11 is an example of the overall configuration of an on-press drawing 4-color single-sided lithographic sheet-fed printing apparatus. Figure 1
As shown in FIG. 1, the four-color single-sided lithographic sheet-fed printing apparatus basically prints the plate cylinder 11, blanket cylinder 12, and impression cylinder 13 of the single-color single-sided printing apparatus shown in FIG. Are provided so that each of them has four pieces.
Although not shown, a known transfer cylinder method or the like is used to transfer the printing paper indicated by K in the figure between adjacent impression cylinders. Although a detailed description is omitted, as can be easily seen from the example of FIG. The plate cylinder has a structure in which a plurality of plates are provided so that printing is performed on the surface. When only one color plate is formed on the plate cylinder, the plate cylinder and blanket cylinder are provided for the number of colors to be printed. (Such a printing apparatus is called a unit-type printing apparatus.) On the other hand, a common impression cylinder type that shares one impression cylinder having a diameter that is an integral multiple of the plate cylinder diameter with respect to a plate cylinder and a blanket cylinder for a plurality of colors. When implementing the present invention in a printing device,
The plate cylinder and blanket cylinder for the number of colors to be printed may share a single impression cylinder, or the plate cylinder and blanket cylinder for multiple colors may have a plurality of structures that share one impression cylinder. ,
A structure in which the total number of blanket cylinders is equal to the number of colors to be printed may be used. In this case, the transfer of the printing paper between the adjacent common impression cylinders can use the known transfer cylinder method or the like.

On the other hand, when a plate of a plurality of colors is formed on a plate cylinder, a plate cylinder and a blanket cylinder are required by a value obtained by dividing the number of colors to be printed by the number of plates on one plate cylinder. For example, when plate materials for two colors are created on a plate cylinder, four-sided four-color printing can be performed by a printing apparatus having two plate cylinders and two blanket cylinders. In this case, the impression cylinder diameter is the same as the plate cylinder diameter for one color,
The impression cylinder is provided with a means for holding the printing paper until the printing of the required color is completed, if necessary, and a known transfer cylinder method or the like is used to transfer the printing paper between the impression cylinders. In the case of a printing press having two plate cylinders and two blanket cylinders each of which has been prepared for the above-described two color plates, two-color printing is performed when one of the impression cylinders holds the printing paper and makes two rotations. The printing paper is transferred between the cylinders, and when the other impression cylinder holds the printing paper and makes two rotations, two-color printing is further performed to complete four-color printing. The number of impression cylinders may be the same as the number of plate cylinders. However, some plate cylinders and blanket cylinders may share one impression cylinder.

On the other hand, when the present invention is embodied as an on-press multicolor two-sided lithographic sheet-fed printing apparatus, a structure in which a known printing sheet reversing means is provided between at least one adjacent impression cylinder of the above-mentioned unit type printing apparatus. Alternatively, a structure in which a plurality of the above-described common impression cylinder type printing apparatuses are arranged and a known printing paper reversing means is provided between at least one adjacent impression cylinder, or the plate cylinder 11 of the single-color single-sided printing apparatus shown in FIG. It has a structure in which a plurality of cylinders 12 are provided so that printing is performed on both sides of the printing paper P. In the structure shown in FIG. 1, when only a plate for one color is formed on the plate cylinder, the plate cylinder and blanket cylinder are provided for the number of colors necessary for printing on both sides of the printing paper. On the other hand, when a plate of a plurality of colors is formed on a plate cylinder as described above, the number of plate cylinders, blanket cylinders, and impression cylinders can be reduced. In addition, when one plate cylinder is shared by several plate cylinders and blanket cylinders, the number of impression cylinders can be further reduced. The plate cylinder is provided with a means for holding the printing paper as needed until printing of the required color is completed. The details are omitted because they can be easily understood from the above-described example of the on-press drawing multicolor single-sided lithographic printing press.

As described above, the example of the sheet-fed printing apparatus has been described as an embodiment of the on-press drawing multicolor lithographic printing apparatus of the present invention. On the other hand, when the present invention is implemented as an on-press drawing multicolor WEB (rolled paper) lithographic printing apparatus, the above-described unit type and common impression cylinder type can be suitably used. When the present invention is embodied as an on-press drawing multi-color WEB double-sided printing apparatus, both the unit type and the common impression cylinder type have a structure in which a known WEB reversing means is provided between at least one adjacent impression cylinder, and a printing paper. This can be achieved by a structure having a plurality of P so that printing is performed on both sides. The BB (blanket-to-blanket) type is the most suitable as an on-press drawing multicolor WEB double-sided printing apparatus. This is a blanket cylinder of one color for printing one side of the WEB, a blanket cylinder (without an impression cylinder) and a blanket cylinder of one color for printing the other side, and a blanket cylinder (without an impression cylinder). Multi-color double-sided printing is achieved by having a structure in which a number of colors are pressed against each other at the time of printing and the WEB passes between blankets pressed during printing.

Another example of the on-press lithographic printing apparatus is that a blanket cylinder has two plate cylinders, and when printing is performed, drawing is performed on the other plate cylinder. You can also. In this case, it is desirable that the drive of the plate cylinder performing drawing is mechanically independent of the blanket. Thus, drawing can be performed without stopping the printing press. Note that, as is easily understood,
This on-press drawing lithographic printing apparatus can be applied to an on-press drawing multicolor single-sided lithographic printing apparatus and an on-press drawing multicolor double-sided lithographic printing apparatus.

Next, the plate (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 provided image receiving layer 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.
As the binder, hydrophilic binders such as polyvinyl alcohol, starch, carboxymethylcellulose, hydroxyethylcellulose, casein, gelatin, polyacrylate, polyvinylpyrrolidone, and polymethylether-maleic anhydride copolymer can be used. . If necessary, a melamine formalin resin, a urea formalin resin, or another crosslinking agent for imparting water resistance may be added.

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

The zinc oxide to be used in the present invention may be, for example, zinc oxide, zinc white, or zinc oxide, as described in “Pigment Handbook” edited by Japan Pigment Technical Association, p. Any of those commercially available as wet zinc white or activated zinc white may be used. That is, zinc oxide includes, as dry methods, French methods (indirect method), American methods (direct method) 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 the binder include styrene copolymer, methacrylate copolymer, acrylate copolymer, vinyl acetate copolymer, polyvinyl butyral, alkyd resin, epoxy resin, epoxy ester Resins, polyester resins, polyurethane resins, and the like. These resins may be used alone or in combination of two or more. The content of the resin in the image receiving layer was represented by a weight ratio of resin / zinc oxide of 9/91.
It is preferably set to ２０20/80.

Desensitization of zinc oxide is carried out by a conventional method using a desensitizing solution. Conventionally, as this type of desensitizing solution, a cyanide compound containing a ferrocyan salt or a ferricyan salt as a main component has been used. Containing treatment solution, ammine cobalt complex,
Known are a cyanide-free treatment liquid containing phytic acid and its derivatives, a guanidine derivative as a main component, a treatment liquid containing an inorganic or organic acid that forms a chelate with zinc ions as a main component, and a treatment solution containing a water-soluble polymer. Have been.
For example, as a cyanide-containing treatment solution,
Nos. 9045 and 46-39403, JP-A-52-76
No. 101, No. 57-107889, No. 54-1172
No. 01 and the like. The surface of the plate material opposite to the image processing layer has a Beck smoothness of 150-7.
It is preferably in the range of 00 (second / 10 cc). As a result, the formed printing plate can be printed satisfactorily without causing displacement or slippage on the plate cylinder even during printing. Here, the Beck smoothness can be measured by a Beck smoothness tester. A Beck smoothness tester presses a test piece under a constant pressure (1 kgf / cm ² (9.8 N / cm ² )) on a highly smooth circular glass plate with a hole in the center.
It measures the time required for a certain amount (10 cc) of air to pass between the glass surface and the test piece under reduced pressure.

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

The specific electric resistance used in the present invention is 10 ⁹ Ωcm.
As the non-aqueous solvent having a dielectric constant of 3.5 or less, preferably a linear or branched aliphatic hydrocarbon, alicyclic hydrocarbon, or aromatic hydrocarbon, and a halogen-substituted product of these hydrocarbons are used. is there. For example, hexane, heptane, octane, isooctane, decane, isodecane, decalin, nonane, dodecane, isododecane, cyclohexane, cyclooctane, cyclodecane, benzene, toluene, xylene, mesitylene, isoper C, isoper E, isoper G, isoper H, isoper L (Isoper; Exxon's trade name), Shellsol 70, Shellsol 71 (Shellsol; Shell Oil's trade name), Amsco OMS, Amsco 460 solvent (Amsco; Spirits' trade name), silicone oil, etc. Alternatively, they are mixed and used. The upper limit of the specific electric resistance of such a non-aqueous solvent is about 1016 Ωcm,
The lower limit of the dielectric constant is about 1.9. These non-aqueous solvents are used alone or as a mixture with other solvents as a washing solution.

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

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

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

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

As such a resin (P), specifically,
Olefin polymers and copolymers (eg, polyethylene,
Polypropylene, polyisobutylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-methacrylate copolymer, ethylene-methacrylic acid copolymer, etc.), vinyl chloride polymer and copolymer (for example, polychlorinated Vinyl, vinyl chloride-vinyl acetate copolymers), vinylidene chloride copolymers, vinyl alkanoate polymers and copolymers, allyl alkanoate polymers and copolymers, and polymers and copolymers of styrene and its derivatives (For example, butadiene-styrene copolymer, isoprene-
Styrene copolymer, styrene-methacrylate copolymer, styrene-acrylate copolymer, etc.), acrylonitrile copolymer, methacrylonitrile copolymer, alkyl vinyl ether copolymer, acrylic ester polymer and copolymer, methacryl Acid ester polymer and copolymer, itaconic acid diester polymer and copolymer, maleic anhydride copolymer, acrylamide copolymer, methacrylamide copolymer, phenol resin, alkyd resin, polycarbonate resin, ketone resin, polyester resin,
Silicon 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, coumarone-indene resin, cyclized rubber-methacrylate copolymer, cyclized rubber-acrylate copolymer, copolymer containing a nitrogen-free heterocycle (for example, furan as a heterocycle, Ring, tetrahydrofuran ring, thiophene ring, dioxane ring, dioxofuran ring, lactone ring,
Benzofuran ring, benzothiophene ring, 1,3-dioxetane ring, etc.), epoxy resin and the like.

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

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

As the pigments, those generally used in the technical field of printing can be used irrespective of inorganic pigments and organic pigments. Specifically, for example, carbon black, cadmium red, molybdenum red, chrome yellow, cadmium yellow, titanium yellow, chromium oxide, viridian, cobalt green, ultramarine blue, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment , Quinacridone-based pigments, isoindolinone-based pigments, dioxazine-based pigments, threne-based pigments, perylene-based pigments, perinone-based pigments, thioindigo-based pigments, quinophthalone-based pigments, metal complex pigments, and other known pigments. It can be used without.

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

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

The resin particles dispersed in the non-aqueous solvent of the present invention, and further including the colored particles, preferably have an average particle size of 0.05 μm to 5 μm. It is more preferably 0.1 μm to 1.0 μm, and still more preferably 0.1 μm to 1.0 μm.
The range is from μm to 0.5 μm. This particle size is CAPA-
500 (trade name, manufactured by Horiba, Ltd.).

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

Examples of the polymerization granulation method include a conventionally known non-aqueous dispersion polymerization method. Specifically, the latest technology of superfine polymer supervised by Soichi Muroi, Chapter 2, CMC Publishing (1991) ), Koichi Nakamura, "Development and Practical Use of Recent Electrophotographic Development Systems and Toner Materials", Chapter 3, (Nippon Scientific Information Co., Ltd., 1985), KEJ Barrett, "Disper
sion 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 × 10 in weight average molecular weight Mw.
^It is preferably ³ to 1 × 10 ⁶ , more preferably 5 × 10 ³
５5 × 10 ⁵ .

As a preferable 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.

[0078]

Embedded image

In the general formula (I), X1 represents —COO
Represents-, -OCO- or -O-. R represents 10 carbon atoms
Represents an alkyl group or an alkenyl group having from 32 to 32, preferably represents an alkyl group or an alkenyl group having from 10 to 22 carbon atoms, and may be linear or branched. It may be. Specifically, decyl group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosanyl group, docosanyl group, decenyl group, dodecenyl group, tridecenyl group, hexadecenyl group, octadecenyl group, linolenyl group, and the like. .

A1 and a2 may be the same or different from each other, and include a hydrogen atom, a halogen atom (eg, a chlorine atom or a bromine atom), a cyano group, an alkyl group having 1 to 3 carbon atoms (eg, a methyl group, Ethyl group, propyl group, etc.),
-COO-Z1 or -CH2 COO-Z1 [Z1
Is an optionally substituted hydrocarbon group having 22 or less carbon atoms (eg, an alkyl group, an alkenyl group, an aralkyl group,
An alicyclic group, an aryl group, etc.).

Among the hydrocarbon groups represented by Z1, preferred hydrocarbon groups include alkyl groups having 1 to 22 carbon atoms which may be substituted (for example, methyl group, ethyl group, propyl group, butyl group, hexyl group). Group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tridecyl group,
Tetradecyl group, hexadecyl group, octadecyl group, eicosanyl group, docosanyl group, 2-chloroethyl group,
A bromoethyl group, a 2-cyanoethyl group, a 2-methoxycarbonylethyl group, a 2-methoxyethyl group, a 3-bromopropyl group, etc., and an optionally substituted alkenyl group having 4 to 18 carbon atoms (for example, 2-methyl- 1-propenyl group, 2-butenyl group, 2-pentenyl group, 3-methyl-
2-pentenyl group, 1-pentenyl group, 1-hexenyl group, 2-hexenyl group, 4-methyl-2-hexenyl group, decenyl group, dodecenyl group, tridecenyl group, hexadecenyl group, octadecenyl group, linolenyl group, etc.),
An aralkyl group having 7 to 12 carbon atoms which may be substituted (for example, benzyl group, phenethyl group, 3-phenylpropyl group, naphthylmethyl group, 2-naphthylethyl group, chlorobenzyl group, bromobenzyl group, methylbenzyl group, An ethylbenzyl group, a methoxybenzyl group, a dimethylbenzyl group, a dimethoxybenzyl group, etc., an alicyclic group having 5 to 8 carbon atoms which may be substituted (for example, cyclohexyl group,
-Cyclohexylethyl group, 2-cyclopentylethyl group, etc.) and an optionally substituted aromatic group having 6 to 12 carbon atoms (for example, phenyl group, naphthyl group, tolyl group, xylyl group, propylphenyl group, butylphenyl group) Octylphenyl, dodecylphenyl, methoxyphenyl, ethoxyphenyl, butoxyphenyl, decyloxyphenyl, chlorophenyl, dichlorophenyl, bromophenyl, cyanophenyl, acetylphenyl, methoxycarbonylphenyl, ethoxy Carbonylphenyl group, butoxycarbonylphenyl group, acetamidophenyl group, propioamidophenyl group, dodecyloylamidophenyl group, etc.).

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

The proportion of the polymer component represented by the general formula (I) in the dispersion polymer is preferably at least 50% by weight, more preferably at least 60% by weight. Specific examples of these dispersion polymers 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.

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

The dispersed resin particles and colored particles (or coloring material particles) in the oil-based ink of the present invention are preferably positively or negatively charged electro-detectable particles. In order to impart an electric detecting property to these particles, it can be achieved by appropriately using a technique of a developer for wet electrophotography. Specifically, the 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. This is performed by using an electric detection material such as a charge control agent described in (1) and other additives.

Specifically, for example, British Patent No. 8934
No. 29, No. 934038, No. 11222397,
U.S. Patent Nos. 3,900,412 and 4,606,899,
JP-A-60-179751, JP-A-60-185963
And JP-A-2-13965. The charge controlling agent as described above is a dispersion medium 1000 as a carrier liquid.
0.001 to 1.0 part by weight based on part by weight is preferred.
If desired, various additives may be added. The upper limit of the total amount of these additives is regulated by the electrical resistance of the oil-based ink. That is, if the specific electric resistance of the ink from which the dispersed particles have been removed is lower than 10 ⁹ Ωcm, it becomes difficult to obtain a high-quality continuous tone image. desirable.

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

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

[0089]

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

Production Example 1 of Resin Particles (PL-1) A mixed solution of 10 g of a dispersion stabilizing resin (Q-1) having the following structure, 100 g of vinyl acetate and 384 g of Isopar H was heated to 70 ° C. while stirring under a nitrogen stream. did. 0.8 g of 2,2'-azobis (isovaleronitrile) (abbreviated AIVN) was added as a polymerization initiator, and the mixture was reacted for 3 hours. Twenty minutes after the initiator was added, cloudiness occurred and the reaction temperature rose to 88 ° C. Further, 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.).

[0091]

Embedded image

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

Example 1 First, an oil-based ink was prepared. Preparation of oil-based ink (IK-1) 10 g of dodecyl methacrylate / acrylic acid copolymer (copolymerization ratio: 95/5 weight ratio), 10 g of nigrosine and 30 g of Shellsol 71 together with glass beads and a paint shaker (Toyo Seiki ( Co., Ltd.) and dispersed for 4 hours to obtain a fine dispersion of nigrosine.

60 g (as solid content) of resin particles (PL-1) manufactured in Production Example 1 of ink resin particles, 2.5 g of the above nigrosine dispersion, FOC-1400 (manufactured by Nissan Chemical Co., Ltd., tetradecyl Alcohol) (15 g) and 0.08 g of octadecene-hemimaleic acid octadecylamide copolymer were diluted to 1 liter of Isopar G to prepare a black oil-based ink.

Next, 2 liters of the oil ink (IK-1) prepared as described above was filled in an ink tank of an ink jet recording apparatus of an on-press lithographic printing apparatus (see FIGS. 1, 2 and 4). Here, a 900 dpi, 64 channel multi-channel head shown in FIG. 4 was used as a recording head. A piezoelectric pump was used for sending the ink. Throwing heater and stirring blade 71 as ink temperature management means
(Tokai Riki Co., Ltd.'s ramond stirrer (model number ST0
2)) is provided in the ink tank 25 and the ink temperature is 30
C., and the temperature was controlled by a thermostat while rotating the stirring blade 71 at 30 rpm. Here, as shown in FIG. 3, the stirring blade 71 was driven and used by a stirring motor 70 (simple stirrer (model number K-1R) manufactured by Tokai Riki Co., Ltd.) as redispersion means for preventing sedimentation and aggregation. . Further, the ink flow path is partially transparent, and an LED light emitting element and a light detecting element are arranged with the ink flow path interposed therebetween, and an ink diluent (Isopar G) or a concentrated ink (IK-
The concentration of solids in one ink was adjusted to be doubled).

As a plate material, an aluminum plate having a graining and anodizing treatment and having a thickness of 0.12 mm was mounted on a plate cylinder with a plate head and a plate edge added thereto by a mechanical device provided on the plate cylinder. Separate the dampening water supply device, the printing ink supply device, and the blanket cylinder so that they do not come into contact with the plate material, remove the dust on the plate material surface by suctioning with an air pump, and then move the recording head close to the plate material to the drawing position and print. The image data to be transmitted to the image data calculation control unit, and the 64-channel recording head was moved while rotating the plate cylinder, thereby discharging oil-based ink onto the aluminum plate to form an image. At this time, the tip width of the ejection electrode of the inkjet head is 10 μm.
m, and according to the output from the optical gap detection device,
Control was performed so that the distance between the head and the plate material was always 1 mm. A voltage of 2.5 kV is constantly applied as a bias voltage, and when performing ejection, a pulse voltage of 500 V is further superimposed, and the pulse voltage is reduced from 0.2 millisecond to 0.0.
Drawing was performed while changing the dot area by changing the area in 256 steps within a range of 5 milliseconds. No foreign matter such as ink agglomerates or dust, no drawing failure due to dust, etc., and no image deterioration due to dot diameter change etc. due to changes in outside air temperature or increase in the number of plate making. Was possible.

Further, the image was strengthened by heating with a xenon flash fixing device (luminous intensity: 200 J / pulse, manufactured by Ushio Inc.) to produce a printing plate. In order to protect the ink jet head, the ink jet recording apparatus was retracted by 50 mm from a position close to the plate cylinder together with the sub-scanning means, and thereafter, printing was performed on the coated printing paper by the normal lithographic printing method as described above. . That is, a printing image is formed by applying a printing ink and a fountain solution, the printing ink image is transferred onto a rotating blanket cylinder together with the plate cylinder, and then a printing coat passing between the blanket cylinder and the impression cylinder. The printing ink image on the blanket cylinder was transferred onto the paper.

The obtained printed matter was an extremely clear image without any jump or blur in the printed image even after passing through 10,000 sheets. 10 minutes after the end of plate making, Isopar G
After cleaning by dripping Isopar G from the head opening, and storing the head in a cover filled with vapor of Isopar G, for three months,
Good prints could be made without the need for maintenance work. During this period, when left for one week, the ink settled to the bottom of the tank and became a bulky aggregate. Plate making was possible.

Embodiment 2 An apparatus shown in FIG. 12 in which the redispersion means (the stirring motor 70 and the stirring blade 71) of the ink jet drawing apparatus 24 shown in FIG.
A dpi full line inkjet head was arranged. Here, a micro gear pump (manufactured by Chuo Rika Kogyo Co., Ltd.) is used, and ink reservoirs are provided between the pump and the ink inflow passage of the recording head, and between the ink recovery passage of the recording head and the ink tank, respectively. The ink was circulated by the difference, the heater and the above-mentioned pump were used as the ink temperature management means, the ink temperature was set at 35 ° C., and the temperature was controlled by a thermostat. Here, as a circulation pump, a submersible pump (Lacy pump (model number P-112) manufactured by Lacey Co., Ltd.) shown at 72 in the figure was also used as a redispersion means for preventing precipitation and aggregation. Then, an electric conductivity measuring device was arranged in the ink flow path, and the density was controlled by diluting the ink or feeding the concentrated ink based on the output signal. As a plate material, the above-described aluminum plate was similarly mounted on a plate cylinder of a lithographic printing apparatus. After removing dust from the surface of the plate using a rotating brush made of nylon, the image data to be printed is transmitted to the image data arithmetic and control unit, and drawing is performed with a full line head while rotating the plate cylinder. An oil-based ink was ejected to form an image. No foreign matter such as ink agglomerates or dust, no drawing failure due to dust, etc., and no image deterioration due to dot diameter change etc. due to changes in outside air temperature or increase in the number of plate making. Was possible. Subsequently, the image was solidified by heat roll fixing (power consumption: 1.2 kW, manufactured by Hitachi Metals, Ltd.) to form a printing plate.

When printing was carried out using the prepressed plate, the printed image was extremely clear without any jumping or blurring even after 10,000 passes. In addition, after circulating Isopar G to the head after the completion of plate making, cleaning was performed by contacting the non-woven fabric containing Isopar G to the tip of the head. Could be produced. Further, when a 600 dpi full line inkjet head of the type shown in FIGS. 8 and 10 was used in place of the inkjet head of the type shown in FIG. 4, similar results were obtained as in the above. . In any case, it takes a long time to obtain a normal dispersion state by using only the liquid sending pump, but by using the re-dispersion means, the ink returns to a good dispersion state in a very short time, and high-quality drawing is performed. Was possible.

Example 3 A full-line head shown in FIG. 8 was used as a recording head in an ink-jet recording apparatus of a four-color one-side planographic printing apparatus (see FIG. 11) for on-press drawing, and a Teflon (registered trademark) contact roller was used. Gap adjustment (gap 0.8mm)
Was done. In addition, the same operation as in Example 1 was performed except that replenishment of concentrated ink to the ink tank was performed according to the number of drawn sheets as the ink density control means, and 5,000 plates were made. As a result, there was no effect of foreign matter such as ink aggregates or dust, poor drawing due to dust, or a change in outside air temperature. The dot diameter was slightly changed by the increase in the number of plate making, but it was within the range where there was no effect. In addition to the above-described flash fixing as described above, the prepressed plate was irradiated with a halogen lamp (QIR manufactured by Ushio Inc.
kW) and fixing by spraying with ethyl acetate.

When the halogen lamp is irradiated, the plate surface temperature is 95
Heating was performed at 20 ° C. for 20 seconds, and in the case of spraying with ethyl acetate, the spray amount was about 1 g / m ² .
As a result, an extremely clear full-color printed matter was obtained without any skipping or blurring in the printed image even after the passing of 10,000 sheets. In particular, in the case of fixing using a heat roll or a halogen lamp, the fixing time can be significantly reduced by winding a heat insulating material (PET film) around the plate cylinder. In this case, use a conductive brush (Sandalon made by Tsuchiya, resistance about 10 ^-1).
Ωcm) to ground the aluminum substrate.

Example 4 The same operation as in Example 1 was performed, except that a paper plate material having a hydrophilic image-receiving layer on the surface shown below was used instead of the aluminum plate of Example 1. Base weight 100g /
m2 ^high- quality paper, on a paper support provided with a water-resistant layer mainly composed of kaolin and resin components of polyvinyl alcohol, SBR latex and melamine resin on both sides of the substrate, with the following composition and the following composition: The dispersion A prepared in this manner was dried, and an image receiving layer was provided so that the coating amount was 6 g / m ² to obtain a paper plate material.

Dispersion A Gelatin (Wako Pure Chemicals first grade) 3 g Colloidal silica (Nissan Chemical; Snowtex C, 20% aqueous dispersion) 20 g Silica gel (Fuji Silysia Chemical; Sylysia # 310) 7 g Hardener 4 g of 100 g of distilled water was dispersed together with glass beads by a paint shaker for 10 minutes.

The obtained printed matter was an extremely clear image without any skipping or blurring in the printed image even after passing 10,000 sheets. On the other hand, when high quality paper was used as printing paper,
A printing failure was caused by installing an air suction pump near the paper feed unit as a paper dust prevention device because a solid crushing defect due to paper dust partially occurred during printing of 1,000 sheets. As a result, no printing failure occurred, and the obtained printed matter was an extremely clear image without flying or blurring even after passing 5,000 sheets. However, after 5,000 sheets are passed, the A3 size image is 0.1m in the vertical direction.
m was observed.

Example 5 In place of the aluminum plate of Example 1, a plate material provided with an image receiving layer which can be made hydrophilic by a desensitizing treatment was used on the surface shown below, and the plate surface was rendered insensitive to oil after forming the plate. The non-image area is hydrophilized using a surface treatment device, the plate material conductive layer is grounded by contact with a conductive leaf spring (made of phosphor bronze) during drawing, and fixing is performed by applying hot air to the plate material. Is Example 1
The same operation was performed.

A high-quality paper having a basis weight of 100 g / m ² was used as a substrate, and a polyethylene film was laminated on both surfaces of the substrate to a thickness of 20 μm to form a water-resistant paper support. The layer coating is applied on one side, and after drying, the applied amount is 10 g / m ² .
On top of this, the dispersion B was dried, and the coated amount was 15 g / m2.
^An image receiving layer was provided so as to obtain a plate material of 2.

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

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

[0110]

Embedded image

The printed matter obtained was an extremely clear image with no skipping or blurring in the printed image even when the number of sheets passed through was 5,000.

Example 6 Instead of the stirring blade 71 of Example 1, a redispersing means shown in FIG. 13 was used. That is, the stirrer 81 (star head stirrer manufactured by Tokai Riki Co., Ltd. (size 5
8)), and a stirrer 82 (a magnetic stirrer manufactured by Tokai Riki Co., Ltd. (model number H)) provided outside the ink tank 25.
S-50E)), the ink was stirred.

Example 7 Instead of the stirring blade 71 of Example 1, a redispersing means shown in FIG. 14 was used. That is, as the ink tank 25, an ultrasonic bath 83 (Ultrasonic cleaner manufactured by Tokai Riki Co., Ltd. (model number US
Using K-2)), the ink was dispersed by ultrasonic vibration.

Example 8 Instead of the stirring blade 71 of Example 1, a redispersing means shown in FIG. 15 was used. That is, the vibrator 84 (φ5) is put into the ink tank 25, and the vibrator 84 is vibrated by the oscillator 85 (ultrasonic disperser (model number UH-50) manufactured by Tokai Riki Co., Ltd.) to disperse the ink. did.

Example 9 Instead of the stirring blade 71 of Example 1, a re-stirring means shown in FIG. 16 was used. That is, a multistage vibrating blade (single shaft type) 86 is put into the ink tank 25, and a low frequency is transmitted to the vibrating blade 86 from the vibrator 87 (super vibration α-stirrer manufactured by Nippon Techno Co., Ltd.). The ink was stirred by the frequency vibration.
In the seventh embodiment, the stirring is not performed by the rotation of the stirring blade as in the first embodiment, but the stirring is performed by the vibration of the stirring blade. Therefore, there is no possibility that air is mixed into the ink. In addition, since the blades do not rotate, they can be installed at the outermost end of the ink tank, and the degree of freedom of installation is large.

On the other hand, in Examples 1 to 9, 3 to
In the case where redrawing is performed without performing stirring and dispersion in advance after the ink liquid flow is stopped for 10 days, the ejection becomes unstable from the beginning in any of the embodiments, and the image is disturbed or the non-ejection state continues. In the worst case, the ejection openings of the head were completely blocked by solid agglomerates of the majority of the ink particles, and rendering was impossible.

The means for preventing aggregation and sedimentation or for re-dispersion shown in the above-described embodiments may be of a large size for a production line. It is preferable to improve the size of the apparatus so that the apparatus can be applied to the on-press lithographic printing apparatus according to the present invention after appropriately reducing the size.

[0118]

According to the present invention, a large number of prints of clear images can be printed. In addition, a printing plate corresponding to digital image data can be stably produced with high image quality directly on a printing press, and inexpensive and high-speed lithographic printing can be performed. further,
Since the ink particles are re-dispersed by the re-dispersion means of the aggregates and precipitates, a high quality printing plate can be produced.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram schematically showing an example of an on-press lithographic printing apparatus used in the present invention.

FIG. 2 is a configuration diagram schematically illustrating an example of a drawing unit of the on-press lithographic printing apparatus used in the present invention.

FIG. 3 is a configuration diagram of an apparatus to which an ink circulation function is added.

FIG. 4 is a schematic configuration diagram illustrating an example of a head provided in an ink jet recording apparatus used in the present invention.

FIG. 5 is a schematic cross-sectional view of the vicinity of an ink discharge unit in FIG.

FIG. 6 is a schematic cross-sectional view of an example of another head provided in an ink jet recording apparatus used in the present invention, in the vicinity of an ink ejection section.

FIG. 7 is a schematic front view of the vicinity of an ink ejection unit in FIG. 5;

FIG. 8 is a schematic configuration diagram showing a main part of an example of another head provided in the ink jet recording apparatus used in the present invention.

FIG. 9 is a schematic configuration diagram of a head obtained by removing a regulating plate from the head of FIG. 8;

FIG. 10 is a schematic configuration diagram showing a main part of an example of another head provided in the ink jet recording apparatus used in the present invention.

FIG. 11 is an overall configuration diagram schematically showing an on-press drawing four-color single-sided lithographic printing machine as an example of a multi-color printing machine used in the present invention.

12 is a configuration diagram of a device in which a part of the device shown in FIG. 3 is replaced.

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

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 On-press lithographic printing apparatus 2 Ink jet recording apparatus 3 Dampening water supply apparatus 4 Printing ink supply apparatus 5 Fixing apparatus 6 Plate surface desensitization apparatus 7 Plate material automatic plate supply apparatus 8 Plate material automatic plate discharging apparatus 9 Plate material (printing plate) 10) Dust removing means 11 Plate cylinder 12 Blanket cylinder 13 Impression cylinder 14 Blanket cleaning device 14 'Impression cylinder cleaning device 15 Paper dust prevention device 21 Image data calculation control unit 22 Recording head 221 Upper unit 222 Lower unit 22a Discharge slit 22b Discharge Electrode 23 Oil-based ink 24 Ink supply unit 25 Ink tank 26 Ink supply device 27 Stirring device 28 Ink temperature management device 29 Ink density control device 30 Encoder 31 Head separation / attachment device 32 Head sub-scanning device 33 First insulating substrate 34 First Second insulating substrate 35 Slope of second insulating substrate 36 Top surface part of second insulating base material 37 Ink inflow path 38 Ink recovery path 39 Backing 40 Groove 41 Head main body 42, 42 'Meniscus regulating plate 43 Ink groove 44 Partition wall 45, 45' Ejection part 46 Partition wall 47 Tip of partition wall 50, 50 'support member 51, 51' groove 52 partition wall 53 upper end portion 54 rectangular portion 55 upper end of partition wall 56 guide protrusion 61, 61 'valve 70 stirring motor 71 stirring blade 72 pump 81 stirrer 82 stirrer 83 ultrasonic bath 84 Ultrasonic vibrator 85 Ultrasonic oscillator 86 Vibration blade 87 Vibrator P Printing paper

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B41J 2/01 B41J 3/04 101Z (72) Inventor Mutsumi Namika 4000, Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Fuji Photo film F-term (reference) 2C020 BA02 2C034 AA12 AA42 BA02 2C056 EA24 EC21 EC29 FA07 FA10 FA13 FB01 2C250 FA03 FB17 FB18 FB19 FB23 2H084 AA38 AA40 AE05 CC05 CC18

Claims (23)

[Claims] An ink jet system in which a plate material is mounted on a plate cylinder of a printing press and oil-based ink is ejected from a recording head on the plate material by using an electrostatic field based on a signal of image data. In the on-press drawing lithographic printing method for forming a printing plate and then performing lithographic printing using the printing plate in that state, the agglomerates of the oil-based ink particles generated by at least the ink flow stop and the like. And / or an on-press lithographic printing method, wherein the sediment is redispersed. 2. The method according to claim 1, wherein the oil-based ink has a specific electric resistance value of 10.
^{2. The on-} press lithographic printing method according to claim 1, wherein solid and hydrophobic resin particles are dispersed at least at room temperature in a non-aqueous solvent having a resistivity of not less than ⁹ Ωcm and not more than 3.5. 3. An ink jet apparatus comprising: a recording head for discharging oil-based ink using an electrostatic field as an image forming means for directly forming an image on a plate material mounted on a plate cylinder of a printing press based on image data signals. An on-press drawing printing apparatus comprising: a drawing device; and a lithographic printing means for performing lithographic printing on a printing plate on which an image has been formed by the image forming means, wherein the oil-based ink particles generated by at least ink flow stationary or the like. An on-press lithographic printing apparatus, comprising: means for redispersing aggregates and / or sediments of (1). 4. An on-press lithographic printing apparatus according to claim 3, further comprising means for redispersing at least aggregates and / or sediments of ink particles immediately before an ink discharge section of said recording head. 5. The means for re-dispersing aggregates and / or sediments of ink particles, at least before ink flow and / or
5. The on-press lithographic printing apparatus according to claim 3, wherein the apparatus operates simultaneously. 6. The means for redispersing aggregates and / or sediments of ink particles comprises one of stirring, dispersion, mixing, and jetting.
4. The method according to claim 3, wherein the operation is performed by the following operations.
An on-press lithographic printing apparatus according to any one of claims 1 to 5. 7. The on-press lithographic printing apparatus according to claim 3, wherein the stirring, dispersing, mixing, and jetting actions are applied singly, in plurality, or in multiples. 8. The on-press lithographic printing method according to claim 3, wherein the stirring, dispersing, mixing, and jetting actions are applied as needed, periodically or continuously. apparatus. 9. The on-machine press according to claim 3, wherein the means for re-dispersing the aggregates and / or sediments of the ink particles is replaceable as a cartridge type. Lithographic printing equipment. 10. The oil-based ink has a specific electric resistance value of 1.
In a non-aqueous solvent having a dielectric constant of not less than 0 ⁹ Ωcm and not more than 3.5,
The on-press lithographic printing apparatus according to any one of claims 3 to 9, wherein solid and hydrophobic resin particles are dispersed at least at room temperature. 11. The image forming apparatus according to claim 3, wherein the image forming unit includes a fixing device for fixing the ink.
0. The on-press lithographic printing apparatus according to any one of 0. 12. The printing apparatus according to claim 3, wherein the image forming unit includes a printing plate surface dust removing unit that removes dust existing on the printing plate surface before and / or during drawing on the printing plate material. An on-press lithographic printing apparatus according to any one of claims 11 to 11. 13. The image forming means according to claim 3, wherein said image forming means performs main scanning by rotating a plate cylinder on which said plate material is mounted when drawing on said plate material. 2. The on-press lithographic printing apparatus according to claim 1. 14. The recording head comprises a single-channel head or a multi-channel head, and performs sub-scanning by moving the recording head in a direction parallel to the axis of the plate cylinder when drawing on the plate material. 14. The on-press lithographic printing apparatus according to claim 13, wherein: 15. The on-press lithographic printing apparatus according to claim 13, wherein the recording head comprises a full line head having a length substantially equal to the width of the plate cylinder. 16. The on-press lithographic printing apparatus according to claim 3, wherein the inkjet drawing apparatus includes an ink supply unit that supplies ink to the recording head. . 17. An on-press lithographic printing apparatus according to claim 16, further comprising an ink recovery means for recovering ink from said recording head, and circulating ink by said ink supply means and said ink recovery means. 18. An on-press lithographic printing apparatus according to claim 3, further comprising an ink stirring means in an ink tank storing the oil-based ink. 19. An on-press drawing according to claim 3, further comprising an ink temperature control means for controlling the temperature of the ink in the ink tank storing the oil-based ink. Lithographic printing equipment. 20. The on-press lithographic printing apparatus according to claim 3, further comprising an ink density control means for controlling an ink density of the ink. 21. The ink jet drawing apparatus according to claim 1, wherein the recording head is moved closer to the plate cylinder when drawing on the plate material, and the recording head is separated from the plate cylinder except when drawing on the plate material. The on-press lithographic printing apparatus according to any one of claims 3 to 20, further comprising contact means. 22. The image forming apparatus according to claim 3, wherein said image forming means includes a print head cleaning means for cleaning said print head at least after the completion of plate making.
22. An on-press lithographic printing apparatus according to any one of claims 21 to 21. 23. The on-press lithographic printing apparatus according to claim 3, wherein the lithographic printing means includes paper dust removing means for removing paper dust generated during lithographic printing. Printing device.