JP2001150788A - Method and apparatus for printing press forming lithography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for printing press forming lithography capable of dealing with digital image data and rapidly printing many printed products of a clear image at a low cost. SOLUTION: In the method for printing press forming lithography comprising the steps of mounting a plate material at a plate cylinder of a printer, directly forming an image on the material based on a signal of image data to form a press plate, and subsequently lithographically printing the plate by using its state, the formation of the image on the material is conducted by an ink jet type for discharging an oily ink by utilizing an electrostatic field.

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 on a printing press. More specifically, the present invention relates to a plate making / printing method and a printing apparatus which perform printing after performing plate making with an oil-based ink and have good plate making quality and print 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. Usually, hydrophilic and lipophilic (ink-receptive) areas are formed imagewise on the surface of the printing plate, and the hydrophilic areas are made ink-repellent by using a fountain solution.

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, 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 in 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 processing with an alkaline developing solution 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 large. Therefore, a system using an inkjet method, which is an inexpensive and compact drawing apparatus, has been attempted.

In Japanese Patent Application Laid-Open No. Hei 4-97848, a plate drum having a hydrophilic or lipophilic surface is provided in place of the conventional plate cylinder, and a lipophilic or hydrophilic image is formed thereon by an ink jet method. A method is disclosed in which the image is formed, the image is removed after printing, and the image is cleaned. 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 ink containing a relatively high concentration of resin. As a result, resin sticking 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, since the plate material is disposable, it is not necessary to remove the image after printing, and the ejection stability is high. However, since the image is formed with wax, the mechanical strength of the image portion is weak, and the printing durability is low because the adhesion to the hydrophilic surface of the printing plate is insufficient.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned 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 An object of the present invention is to provide an on-press lithographic printing apparatus.
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 prints of clear and high-quality images with an inexpensive apparatus and a simple method.

[0010]

According to a first aspect of the present invention, there is provided a lithographic printing method comprising the steps of: mounting a plate on a plate cylinder of a printing press; In the on-press drawing lithographic printing method in which an image is formed directly on the basis of the above-mentioned signal to prepare a printing plate, and the printing plate is used in that state to subsequently perform lithographic printing, the formation of an image on the printing plate is performed by static printing. The method is performed by an inkjet method in which oil-based ink is ejected using an electric field. The lithographic printing method according to claim 2, wherein the oil-based ink has solid and hydrophobic resin particles dispersed 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. Characterized in that: 4. The on-press lithographic printing apparatus according to claim 3, wherein the image forming apparatus directly forms an image based on a signal of image data on a plate material mounted on a plate cylinder of the printing press. An on-press drawing printing apparatus comprising: a lithographic printing means for performing lithographic printing on a printing plate formed with an ink jet printing apparatus, wherein the direct image forming means is an ink jet drawing apparatus for discharging oil-based ink using an electrostatic field. And The lithographic printing apparatus for on-press drawing according to claim 4, wherein the oil-based ink is a resin particle which is solid and hydrophobic 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. Are dispersed. According to a fifth aspect of the present invention, in the on-press lithographic printing apparatus, the direct image forming means includes a fixing device for the ink. 7. The on-press lithographic printing apparatus according to claim 6, wherein the direct image forming means includes plate material surface dust removing means for removing dust present on the plate material surface before and / or during drawing on the plate material. It is characterized by having. Claim 7
The on-press lithographic printing apparatus described above is characterized in that, when drawing on the plate material, the direct image forming means performs main scanning by rotating a plate cylinder on which the plate material is mounted. The on-press lithographic printing apparatus according to claim 8, wherein the inkjet drawing apparatus includes a single head or a multi-head,
The sub-scan is performed by moving the recording head in the axial direction of the plate cylinder when drawing on the plate material.
A lithographic printing apparatus according to a ninth aspect of the present invention is characterized in that the inkjet drawing apparatus includes a full line head having substantially the same length as the width of the plate cylinder. According to a tenth aspect of the present invention, the on-press lithographic printing apparatus is characterized in that the inkjet drawing apparatus includes an ink supply unit for supplying ink to the recording head. An on-press lithographic printing apparatus according to an eleventh aspect of the present invention is characterized in that the lithographic printing apparatus includes an ink recovery unit that recovers ink from the recording head, and circulates ink by the ink supply unit and the ink recovery unit. According to a twelfth aspect of the present invention, there is provided an on-press lithographic printing apparatus comprising an ink agitating means in an ink tank storing the oil-based ink. According to a thirteenth aspect of the present invention, there is provided an on-press lithographic printing apparatus comprising an ink temperature control unit for controlling the temperature of the ink in an ink tank storing the oil-based ink. According to a twelfth aspect of the present invention, there is provided an on-press lithographic printing apparatus further comprising an ink density control unit for controlling an ink density of the ink. The on-press lithographic printing apparatus according to claim 15, wherein the ink jet drawing apparatus brings the recording head close to the plate cylinder when drawing on the plate material, and moves the recording head except when drawing on the plate material. A recording head separating means for separating the recording head from the plate cylinder; An on-press lithographic printing apparatus according to claim 16, wherein the direct image forming means includes a recording head cleaning means for cleaning the recording head at least after the completion of plate making. An on-press lithographic printing apparatus according to claim 17 is characterized in that the lithographic printing means includes paper dust removing means for removing paper dust generated during lithographic printing.

[0011]

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 inkjet method in which oil-based ink is discharged 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. As described above, the resin particles are ejected as aggregates having a high concentration, and the thickness of the printed dots 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 inkjet method, the size of the ejected ink droplet is determined by the ejection position, the shape of the electrode, and the conditions for applying the electric field, and a small ink droplet can be obtained without reducing the ejection nozzle diameter or the slit width. By controlling the conditions, the dot diameter on the plate material can be controlled. Therefore, according to the present invention, it is possible to control a printing-resistant minute image without the problem of ink clogging of the head, and it is possible to print a large number of clear images.

An example of a configuration of an on-press lithographic printing apparatus used to carry 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 lithographic printing apparatus. FIGS. 3 to 9 are for explaining the ink jet recording apparatus provided in the on-press lithographic printing apparatus shown in FIGS. 1 and 10. FIG. FIG. 10 is an example of the overall configuration of an on-press drawing four-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 a “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 transfer blanket cylinder 12 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 thereto to the printing paper P. The impression cylinder 13 is disposed 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 serves as a counter electrode of the discharge head electrode in 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, 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 area.

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. However, as the dampening water supply device 3, other known devices such as a synflo water supply system and a continuous water supply system can be used. 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 installed 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. Thereby, it is possible to effectively prevent the ink from adhering to the plate material due to the dust that has entered between the head and the plate material during the plate making, and to obtain a good plate making. As the dust removing means, in addition to 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. In the present invention, it is preferable to use either air suction or air blowing. 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 onto 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 for 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 Magicjisk 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 easier 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 the oil-based ink image as a halftone dot by using an ink-jet ejection head 22 (see FIG. 2 and described in detail later) as a recording head of the ink-jet recording apparatus 2, calculation of a dot area ratio is also performed. .

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

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

First, the plate material 9 is mounted on the plate cylinder 11 using the automatic plate feeding device 7. At this time, the plate material is closely fixed on the plate cylinder by a mechanical method using a known plate head / butt holding device, an air suction device, or the like, or an electrostatic method. Inkjet recording device 2
It can be prevented from being damaged due to contact with. 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. Can also. In particular,
For example, there is a method of disposing a pressing roller upstream and downstream of the plate cylinder drawing position. Also, in the process of fixing the plate,
By providing a means for preventing the edge of the plate from contacting the ink supply roller, it is possible to prevent the plate surface from being stained and 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 arithmetic control unit 21 calculates the discharge position of the oil-based ink and the halftone dot area ratio at that position in accordance with the input image data. These calculation data are temporarily stored in the buffer. The image data calculation control unit 21 rotates the plate cylinder 11 to bring the ejection head 22 closer to a position close to the plate cylinder 11 by the head separation / contact device (recording head separation / contact means) 31. The distance between the ejection head 22 and the surface of the plate material 9 on the plate cylinder 11 is controlled by mechanical distance control such as an abutment roller or by control of a head separation / contact device based on 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 ejection head 22, a single head, a multi-head, or a full line head can be used, and the main scanning is performed by rotating the plate cylinder 11. In the case of a multi-head or a full line head having a plurality of discharge units, the arrangement direction of the discharge units is set in the axial direction. Further, in the case of a single head or a multi-head, the image data arithmetic control unit 21 controls the head 2 for each rotation of the plate cylinder 11.
2 is moved in the axial direction 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. As a result, a halftone image corresponding to the density of the print document is drawn on the plate material 9 with the oil-based ink. This operation continues until an oil-based ink image for one color of the printing original is formed on the plate material 9 and a printing plate is completed. On the other hand, when the ejection head 22 is a full line head having a length substantially equal to the width of the plate cylinder, an oil-based ink image for one color of a print document is formed on the plate material 9 by one rotation of the plate cylinder. A printing plate is completed. By performing main scanning by rotating the plate cylinder in this manner, it is possible to increase the positional accuracy in the main scanning direction and perform high-speed drawing.

Next, in order to protect the ejection head 22,
The ejection head 22 is retracted away from a position close to the plate cylinder 11. At this time, the ejection head 22 and the head sub-scanning means 32 may be separated or contacted together, or the ejection head 22 and the ink supply unit 24 and all the head sub-scanning means 32 may be separated and attached together. You can also touch. In addition, the fixing device 5 and the dust removing device 10 are also provided with separating / contacting means together with the ejection 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 a slide 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 as described above, the head can be protected from physical damage or contamination, and a longer life can be achieved.

The formed oil-based ink image is reinforced by heating or the like in the fixing device 5. As the fixing means of the ink, known means such as heat fixing, solvent fixing, and flash exposure fixing can be used. In the heat fixing, halogen lamp irradiation, 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 heated in advance, 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 material and heating only the plate material alone or in combination. In solvent fixing, a solvent capable of dissolving the resin component in the ink, such as methanol or ethyl acetate, is sprayed, and excess solvent vapor is collected. Also, flash fixing using a xenon lamp or the like is known as a fixing method of electrophotographic toner, and has an advantage that fixing can be performed in a short time. At least in the process from the formation of the oil-based ink image by the ejection head 22 to the fixing by the fixing device 5,
It is desirable that the dampening solution supply device 3, the printing ink supply device 4, and the blanket cylinder 12 are kept out of contact with the plate material 9 on the plate cylinder.

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 together 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 head, and in this case, the ink supply unit also has a recovery circulation function. The ink stirring means 27 suppresses precipitation and aggregation of the solid components of the ink, and the necessity of cleaning the ink tank is reduced. Rotary wings, ultrasonic vibrators,
A circulating pump can be used and used from these or in combination. The ink temperature management means 28 is arranged such that a high-quality image can be stably formed without a change in the physical properties of the ink due to a change in the surrounding temperature and a change in the dot diameter. As the ink temperature 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 15 ° C or more and 60 ° C or more.
The following is desirable, and more preferably it is 20 ° C. or more and 50 ° C. or less. 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.

Further, the printing apparatus has an ink density control means 29 for performing high-quality drawing. As a result, it is possible to effectively suppress the occurrence of bleeding on the plate due to a decrease in the solid concentration in the ink, the jump or blur of the printed image, or the change in the dot diameter on the plate due to the increase in the solid concentration. The ink 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, in the ink tank, or in the ink flow path, provided an optical detector, a conductivity measuring device, a clay measuring device alone or in combination thereof, and controlled by the output signal, When the management is performed based on the number of drawn sheets, the supply of the liquid from the replenishment concentrated ink tank or the 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 drive unit different from the drive unit during printing for driving the plate cylinder when performing drawing by the ink jet recording apparatus. At that time, it is desirable to drive the plate cylinder only by mechanically separating it from the blanket cylinder, impression cylinder, and the like. 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 to drive only the plate cylinder. When performing high-quality drawing, such means alone,
Alternatively, use in combination.

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

FIGS. 3 and 4 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 and the like 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, and platinum on a lower unit 222 made of an insulating base material, and then a photoresist is formed thereon. A photoresist pattern is exposed through a mask of a predetermined electrode pattern, developed and developed to form a photoresist pattern of the discharge electrode 22b, and then etched or mechanically removed. Or by a known method such as a method combining them.

In the head 22, a voltage is applied to the ejection electrode 22b in accordance with a digital signal of image pattern information. As shown in FIG. 3, a plate cylinder 11 serving as a counter electrode is provided so as to face the discharge electrode 22b, and the plate material 9 is provided on the plate cylinder 11 serving as the counter electrode. By applying a voltage, a circuit is formed between the discharge electrode 22b and the plate cylinder 11 serving as the counter electrode, and the oil-based ink 23 is discharged from the discharge slit 22a of the head 22 and provided on the plate cylinder 11 serving as the counter electrode. An image is formed on the obtained plate material 9.

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, etc.
It is used in the range of the tip width of 100 μm. For example, a discharge electrode 22b having a tip of 20 μm in width is used, a 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 for 0.1 millisecond to 40 μm. Dots can be formed on the plate material 9.

FIGS. 5 and 6 are a schematic cross-sectional view and a schematic front view, respectively, showing the vicinity of the ink discharge portion of another example of the discharge head. In the figure, reference numeral 22 denotes a discharge head, which has a first insulating base material 33 having a gradually decreasing shape. A second insulating base material 34 is provided on the first insulating base material 33 so as to be spaced apart and opposed to the first insulating base material 33, and a slope portion 35 is formed at the tip of the second insulating base material 34. The first and second insulating substrates are formed of, for example, plastic, glass, ceramics, or the like. The upper surface portion 36 that forms an acute angle with the slope portion 35 of the second insulating base material 34 includes:
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 passage 37 is formed between the second insulating base material 33 and the second insulating base material as means for supplying the ink 23 to the ejection portion, and an ink recovery passage is formed below the second insulating base material. 38 are formed. The ejection electrode 22b is a second
A conductive material such as aluminum, nickel, chromium, gold, and 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 this 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 the 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 becomes difficult to discharge, or the recording frequency is lowered, and if the space is too wide, the meniscus is not stable. This is because the ejection becomes unstable.

The ejection electrode 22b is connected to the image data calculation control unit 21. When recording is performed, a voltage is applied to the ejection electrode based on the image information to eject ink on the ejection electrode, and the ejection unit is connected to the ejection electrode 22b. 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 unit of an ink supply device (not shown).

When a uniform ink flow on the ejection section is required, a groove 40 may be provided between the ejection section and the ink recovery path. FIG. 6 is a schematic front view showing the vicinity of the ink ejection portion of the ejection head, and the inclined surface of the second insulating base material 34 has an ink collection path 3 near the boundary with the ejection electrode 22b.
A plurality of grooves 40 are provided toward 8. This groove 4
Numerals 0 are arranged in the direction in which the ejection electrodes 22b are arranged, and the ink is guided to each groove 40 from the opening on the side of the ejection electrode 22b by the capillary force, and the guided ink is transferred to the ink recovery path 3.
8 has the function of discharging. The groove 40 sucks a certain amount of ink near the tip of the discharge electrode by a capillary force corresponding to the opening diameter. Therefore, it has a function of forming an ink flow having a constant liquid thickness near the tip of the discharge electrode. 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
３００300 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 at the end in order to form a high-quality image, for example, for printing. Specific numerical values vary depending on conditions and the like, but are usually used in a range of a tip width of 5 to 100 μm.

FIGS. 7 and 8 show other examples of the ejection head used to carry out the present invention. FIG. 7 is a schematic view showing only a part of the head for explanation. As shown in FIG. 7, 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 section. Further, the control plates 42 and 42 '
The head 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, or platinum on the head body 40 made of an insulating material by a known method similar to the case 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 tip of the partition wall 44 at the center of the cell forms the ejection portion 4.
5, 45 'are provided. In the ejection portions 45 and 45 ', the partition walls are thinner than the other partition portions 44 and are sharpened. Such a head body is formed by a known method such as machining, etching, or molding of an insulating material block. The thickness of the partition wall at the discharge portion is preferably 5 to 100 μm, and the radius of curvature of the sharpened tip is preferably 5 to 50 μm. The tip of the discharge section may be slightly chamfered, such as 45 '. Although only two cells are shown in the figure,
The cells are partitioned by a partition wall 46, and a tip 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 feeding means 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 means (not shown), and as a result, fresh ink is always supplied to the ejection unit. In this state, the 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 the plate material on the surface thereof, which is provided so as to face the ejection unit. An image is formed on the plate material.

Another embodiment of the ejection head will be described with reference to FIG. As shown in FIG.
2 has a pair of substantially rectangular plate-shaped support members 50 and 50 '. These support members 50, 50 'are made of a plate-like plastic, glass, ceramic or the like having a thickness of 1 to 10 mm having an insulating property, and one surface of each is parallel to each other according to the recording resolution. A plurality of elongated rectangular grooves 51, 51 '(not shown) are formed. Each groove 51, 51 ′ has a width of 10 to 200 μm and a depth of 10 to 30
The discharge electrode 22b is preferably formed in a range of 0 μm, and the whole or a part thereof is formed with the discharge electrode 22b. Thus, the plurality of grooves 51, 5 are provided on one surface of the support members 50, 50 '.
By forming 1 ', a plurality of rectangular partitions 52 are inevitably provided between the grooves 51. Each support member 5
0, 50 'are combined so that the surfaces on which the grooves 51, 51' are not formed face each other. That is, the ejection head 22
Has a plurality of grooves on its outer peripheral surface for flowing ink. Grooves 5 formed in each support member 50, 50 '
1, 51 'are connected in a one-to-one correspondence via a rectangular portion 54 of the discharge head 22, and the rectangular portion 54 to which each groove is connected is a predetermined distance (50
５００500 μm). That is, on both sides of each rectangular portion 54, each partition 52 of each support member 50, 50 '
Is provided so that the upper end 55 thereof protrudes from the rectangular portion 54. A guide protrusion 56 made of an insulating material as described above is provided so as to protrude from each rectangular portion 54 to form a discharge portion.

When the ink is circulated through the ejection head 22 configured as described above, the ink is supplied to each rectangular portion 54 through each groove 51 formed on the outer peripheral surface of one support member 50, and the ink is supplied to the opposite side. Each groove 5 formed in the supporting member 50 '
Discharge via 1 '. In this case, the ejection head 22 is inclined at a predetermined angle to enable smooth ink distribution. That is, the ejection head 22 is inclined such that the ink supply side (support member 50) is located above and the ink discharge side (support member 50 ') is located below.
As described above, when the ink is circulated through the ejection head 22,
The ink passing through each rectangular portion 54 gets wet along each protrusion 56, and an ink meniscus is formed near the rectangular portion 54 and the protrusion 56. Then, 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 ejection head 22.

The above-described head 22 shown in FIGS. 3 to 9 may include a maintenance device such as a recording head cleaning unit as necessary. For example, if the hibernation state continues or if a problem occurs in image quality, the tip of the ejection head is wiped with a flexible brush, brush, cloth, or the like, circulates only the ink solvent, supplies only the ink solvent, Alternatively, a good drawing state can be maintained by performing means such as sucking the discharge portion while circulating the ink alone or in combination. In order to prevent the ink from sticking, it is 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 part, the jet of air, ink, or ink solvent is forcibly injected from the ink flow path, or the head is immersed in the ink solvent. Applying a sound wave is also effective, and these methods can be used alone or in combination.

Next, as a specific example of the present invention, an on-press drawing multicolor single-sided lithographic printing apparatus will be described. FIG. 10 is an example of the overall configuration of an on-press 4-color single-sided lithographic sheet-fed printing apparatus. FIG.
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. , Respectively, so that four are provided.
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 understood from the example of FIG. 10, the other multiple-color single-sided printing apparatus basically uses the same printing cylinder P as the printing drum P, the blanket cylinder 12 and the impression cylinder 13 of the single-color single-sided printing apparatus. It 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 have a structure in which one impression cylinder is shared, or the plate cylinder and blanket cylinder for multiple colors may have a plurality of structures in which one impression cylinder is shared. ,
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 formed on a plate cylinder, four-color printing on one side 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 machine having two plate cylinders and two blanket cylinders each of which forms the above-described plate material for two colors, two-color printing is performed when one impression cylinder 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. Although the number of impression cylinders may be the same as the number of plate cylinders, one plate cylinder may be shared by several plate cylinders and blanket cylinders.

On the other hand, when the present invention is embodied as an on-press drawing double-color double-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 unit-type printing apparatus described above. Alternatively, a structure in which a plurality of the above-described common impression cylinder type printing apparatuses are arranged and a known printing sheet 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 plurality of color plates are formed on the plate cylinder as described above, the number of plate cylinders, blanket cylinders, and impression cylinders can be reduced. Further, 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 printing paper until printing of a required color is completed, if necessary. The details will be 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 the 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 Ps 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 during printing, and the web passes between blankets pressed during printing.

Another example of an 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. 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,
The 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.

Zinc oxide to be used in the present invention may be, for example, zinc oxide, zinc oxide or zinc oxide, as described in “Pigment Handbook” edited by Japan Pigment Technical Association, page 19, Seibundo Co., Ltd. (1968). Any of those commercially available as wet zinc white or activated zinc white may be used. That is, zinc oxide includes, as a dry method, a French method (indirect method), an American method (direct method), and a wet method, depending on the starting materials and the production method. For example, Shodo Chemical Co., Ltd., Sakai Chemical Co., Ltd. ), Hakusui Chemical Co., Ltd., Honjo Chemical Co., Ltd., Toho Zinc Co., Ltd., Mitsui Kinzoku Kogyo Co., Ltd., and the like.

Specific examples of the resin used as a binder include a vinyl chloride-vinyl acetate copolymer, a styrene-butadiene copolymer, a styrene-methacrylate copolymer, a methacrylate copolymer, and an acrylate copolymer. , Vinyl acetate copolymer, polyvinyl butyral, alkyd resin, epoxy resin, epoxy ester resin, polyester resin, polyurethane resin 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 is preferably from 9/91 to 20/80 in terms of resin / zinc oxide weight ratio.

Desensitization of zinc oxide is conventionally performed by using a desensitizing treatment liquid of this type, a treatment liquid containing a cyanide compound containing ferrocyanate or ferricyanate as a main component, an ammine cobalt complex, phytic acid and derivatives thereof. Also, a cyan-free treatment liquid containing a guanidine derivative as a main component, a treatment liquid containing an inorganic acid or an organic acid that forms a chelate with zinc ions as a main component, a treatment liquid containing a water-soluble polymer, and the like are known. For example, as a cyanide-containing treatment solution,
JP-B-44-9045, JP-B-46-39403, JP-A-52-76101, JP-A-57-107889, and JP-A-57-107889.
4-117201 and the like.

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 an electric resistance of 10 ⁹ Ωcm or more and a dielectric constant of 3.5 or less.

The non-aqueous solvent having an electric resistance of 10 ⁹ Ωcm or more and a dielectric constant of 3.5 or less used in the present invention is preferably a linear or branched aliphatic hydrocarbon, alicyclic hydrocarbon or aromatic hydrocarbon. There are hydrogen and halogenated forms of these hydrocarbons. 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; trade name of Exxon), Shellsol 70, shell Sol 71 (Shellsol; trade name of Shell Oil Co.), Amsco OMS, Amsco 460 solvent (Amsco; trade name of Spirits Co., Ltd.), silicone oil and the like are used alone or in combination. The upper limit of the electric resistance of such a non-aqueous solvent is about 10 ¹⁶ Ωcm, and the lower limit of the dielectric constant is about 1.9.

The reason why the electric resistance of the non-aqueous solvent used is within the above range is that when the electric resistance is low, the electric resistance of the ink is not appropriate and the ejection of the ink by the electric field is deteriorated. The reason for setting the range is that when the dielectric constant is high, the electric field in the ink is easily relaxed, whereby the ejection of the ink is easily deteriorated.

The resin particles dispersed in the non-aqueous solvent may be 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 a softening point, the affinity between the surface of the image receiving layer of the printing plate and the resin particles is increased, and the bonding between the resin particles on the printing plate is strong. Therefore, the adhesion between the image portion and the image receiving layer is improved, and the printing durability is improved. In contrast,
Regardless of whether the glass transition point or the softening point is low or high, the affinity between the surface of the image receiving layer 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 copolymer (for example, polyvinyl chloride, chloride Vinyl-vinyl acetate copolymers), vinylidene chloride copolymers, vinyl alkanoate polymers and copolymers, allyl alkanoate polymers and copolymers, polymers and copolymers of styrene and its derivatives (for example, butadiene) -Styrene copolymer, isoprene-styrene copolymer, styrene-methacrylate copolymer, styrene-
Acrylate copolymer), acrylonitrile copolymer, methacrylonitrile copolymer, alkyl vinyl ether copolymer, acrylate polymer and copolymer, methacrylate polymer and copolymer, itaconic diester polymer And copolymers, maleic anhydride copolymers, acrylamide copolymers, methacrylamide copolymers, phenolic resins, alkyd resins, polycarbonate resins, ketone resins, polyester resins, silicone resins, amide resins, hydroxyl- and carboxyl-modified polyesters Resin, butyral resin, polyvinyl acetal resin, urethane resin, rosin resin, hydrogenated rosin resin, petroleum resin, hydrogenated petroleum resin, maleic acid resin, terpene resin, hydrogenated terpene resin, cumarone-indene resin, cyclized rubber Meta Acrylic acid ester copolymers, cyclized rubber - acrylic acid ester copolymers, copolymers containing a heterocyclic ring containing no nitrogen atom (e.g. a heterocyclic ring, a furan ring, a tetrahydrofuran ring, a 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 is difficult to obtain affinity between the ink and the image receiving layer of the printing original plate, and a good image cannot be obtained, or problems such as reduced printing durability tend to occur. When the content is large, there are problems such as difficulty in obtaining a uniform dispersion, difficulty in clogging of the ink in the discharge head, and difficulty in obtaining 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 the purpose of plate inspection after plate making.
As the coloring material, 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, titanium cobalt green, ultramarine blue, Prussian blue, cobalt blue, azo pigments, phthalocyanine-based Pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, threne pigments, perylene pigments, perinone pigments, thioindigo pigments, quinophthalone pigments, metal complex pigments, and other conventionally known pigments are particularly limited. Can be used without.

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

These coloring materials may be dispersed in a non-aqueous solvent as the dispersed particles themselves in addition to 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 by coloring the surface of the dispersed resin particles into colored particles. General.

The resin particles dispersed in the non-aqueous solvent of the present invention, and also the colored particles and the like, preferably have an average particle 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 the 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 of kneading a dispersion-assisting polymer (or a coating polymer) in advance to form a kneaded product, pulverizing the mixture, and then dispersing the mixture in the presence of a dispersing polymer may be used. Specifically, a method for producing a paint or a liquid developer for electrostatography can be used. For example, these methods are described in "Paint Flow and Pigment Dispersion" edited by Kenji Ueki, Kyoritsu Shuppan (1971), "Solomon , Paint Science, "Paint and Surface Coating Theo
ry and Practice ", Yuji Harasaki" Coating Engineering "Asakura Shoten (1971), Yuji Harasaki" Basic Science of Coatings "Maki Shoten (1977) and other books.

Examples of the polymerization granulation method include a conventionally known non-aqueous dispersion polymerization method. Specifically, the latest technology of ultrafine 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, (Japan Science 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 .

Preferred examples of the soluble repeating unit of the dispersion polymer used in the present invention include a polymerization component represented by the following general formula (1).

[0075]

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

A ₁ and a ₂ may be the same or different from each other, and are preferably a hydrogen atom, a halogen atom (for example, a chlorine atom, a bromine atom, etc.), a cyano group, and a carbon number of 1 to 3.
Alkyl group (e.g., methyl group, ethyl group, propyl group, etc.), - COO-Z ₁ or -CH ₂ COO-Z
₁ [Z ₁ represents a hydrogen atom or 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.)].

Specifically, Z ₁ represents a hydrocarbon group in addition to a hydrogen atom.
To 22 optionally substituted alkyl groups (e.g., methyl, ethyl, propyl, butyl, heptyl, hexyl, octyl, nonyl, decyl, dodecyl, tridecyl, tetradecyl, hexadecyl) Group,
Octadecyl, eicosanyl, docosanyl, 2-
Chloroethyl group, 2-bromoethyl group, 2-cyanoethyl group, 2-methoxycarbonylethyl group, 2-methoxyethyl group, 3-bromopropyl group, etc.), having 4 to 18 carbon atoms
Optionally substituted alkenyl groups (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., and an optionally substituted aralkyl group having 7 to 12 carbon atoms (e.g., benzyl) Group, phenethyl group, 3-
Phenylpropyl group, naphthylmethyl group, 2-naphthylethyl group, chlorobenzyl group, bromobenzyl group, methylbenzyl group, ethylbenzyl group, methoxybenzyl group, dimethylbenzyl group, dimethoxybenzyl group, etc.),
An optionally substituted alicyclic group having 5 to 8 carbon atoms (eg, cyclohexyl group, 2-cyclohexylethyl group, 2-cyclopentylethyl group, etc.), and an optionally substituted aromatic group having 6 to 12 carbon atoms (For example, phenyl, naphthyl, tolyl, xylyl, propylphenyl, butylphenyl, octylphenyl, dodecylphenyl, methoxyphenyl, ethoxyphenyl, butoxyphenyl, decyloxyphenyl, chlorophenyl) , Dichlorophenyl, bromophenyl, cyanophenyl, acetylphenyl, methoxycarbonylphenyl, ethoxycarbonylphenyl, butoxycarbonylphenyl, acetamidophenyl, propioamidophenyl, dodecylylamidophenyl, etc.) Be mentioned

The dispersing polymer may contain another repeating unit 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 the like.
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 an emulsion (latex) or the like, it is preferable that the dispersion polymer is added in advance during the polymerization. When the dispersing polymer is used, the amount added is about 0.05 to 4% by weight based on the whole ink.

The dispersion resin particles and the color particles (or color material particles) in the oil-based ink of the present invention are preferably positively or negatively chargeable particles. In order to impart an electric detecting property to these particles, it can be achieved by appropriately utilizing a technique of a developer for wet electrophotography. Specifically, the above-mentioned “Recent development and commercialization of electrophotographic development systems and toner materials” 1
39-148, edited by the Society of Electrophotography, "Basics and Application of Electrophotographic Technology", 497-505 (Corona Co., 1988), Yuji Harazaki, "Electrophotography" 16 (No. 2), 44 (1977), etc. And the other additives.

Specifically, for example, British Patent No. 8934
No. 29, No. 934038, U.S. Pat. No. 112239
No. 7, No. 3900412, No. 460989,
JP-A-60-179751, JP-A-60-185963
And JP-A-2-13965. The charge control 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 electric resistance of the ink from which the dispersed particles are removed is lower than 10 9 Ωcm, it becomes difficult to obtain a high-quality continuous tone image. Therefore, it is necessary to control the amount of each additive within this limit. is there.

[0084]

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

Production Example 1 of Resin Particles (PL-1) 10 g of a dispersion stabilizing resin (Q-1) having the following structure,
g and Isopar H384g were heated to a temperature of 70 ° C. while stirring under a nitrogen stream. As a polymerization initiator, 2,2'-azobis (isovaleronitrile) (abbr.
I. V. N. ) 0.8 g was added and reacted for 3 hours. Twenty minutes after the initiator was added, cloudiness occurred, and the reaction temperature was 88 ° C.
Up. 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 is CAPA-500 (manufactured by Horiba, Ltd.)
Was measured.

[0086]

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

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

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

Next, an on-press lithographic printing apparatus (FIGS. 1-2)
2) of the oil-based ink (IK-1) prepared as described above was filled in an ink tank. Here, 900 shown in FIG.
A dpi, 64-channel multihead was used. A throwing heater and a stirring blade were provided in the ink tank as ink temperature management means, the ink temperature was set to 30 ° C., and the temperature was controlled by a thermostat while rotating the stirring blade at 30 rpm. Here, the stirring blade was also used as a stirring means for preventing sedimentation and aggregation. Further, the ink flow path is partially transparent, and an LED light emitting element and a light detecting element are disposed with the ink flow path interposed therebetween. The density was adjusted by a factor of 2).

As a plate material, a 0.12 mm-thick aluminum plate subjected to graining and anodizing was mounted with a mechanical device provided on the plate cylinder, with the bottom of the plate added. 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 discharge head close to the plate material to the drawing position and print. The image data to be transmitted to the image data arithmetic control unit, and the 64-channel ejection head was moved while rotating the plate cylinder, thereby ejecting oil-based ink onto the aluminum plate to form an image. At this time, the tip width of the ejection electrode of the ink jet head was set to 10 μm, and control was performed such that the distance between the head and the plate material was always 1 mm according to the output from the optical gap detection device. In addition, a voltage of 2.5 KV is always applied as a bias voltage at the time of ejection, and a pulse voltage of 500 V is further superimposed at the time of ejection, and the pulse voltage is from 0.2 millisecond to 0.05. Drawing was performed while changing the dot area by changing the area in 256 steps within the range of milliseconds. There are no drawing defects due to dust at all.
No image deterioration due to a change in dot diameter or the like was observed even when the number of plate making increased, and good plate making was possible.

Further, the image was strengthened by heating with a xenon flash fixing device (luminous intensity: 200 J / pulse, manufactured by Ushio Inc.) to produce a printing plate. In order to protect the ink jet head, the ink jet 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 printing paper by a 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 blanket cylinder rotating 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 skipping or blurring in the printed image even after passing 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 3 months
Good prints could be produced without the need for maintenance work.

Example 2 A circulation pump was used as the stirring means, and FIGS.
A 600 dpi full line inkjet head of the type shown in FIG. Here, a pump is used, and ink reservoirs are respectively provided between the pump and the ink inflow path of the discharge head, and between the ink recovery path of the discharge head and the ink tank. As a means, use a heater and the above-mentioned pump,
The ink temperature was set at 35 ° C. and controlled with a thermostat. Here, the circulation pump was also used as a stirring means for preventing precipitation and aggregation. In addition, a 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-mentioned 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 defective drawing due to dust was observed at all, and no image deterioration due to a change in dot diameter or the like was observed even when the outside air temperature changed or the number of plate making increased, and good plate making was possible. 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 clear without any jumping or blurring even after 10,000 passes. In addition, after the head was cleaned by circulating Isopar G to the head after the completion of plate making, cleaning was performed by bringing a nonwoven fabric containing Isopar G into contact with the tip of the head, and no maintenance work was required for three months. Good printed matter was produced.

Example 3 In an ink jet recording apparatus of a 4-color single-sided lithographic printing apparatus (see FIG. 10) for on-press drawing, a full line head shown in FIG. 7 was used as a discharge head, and a gap was adjusted by a Teflon-made contact roller ( Gap 0.8 mm). In addition, the same operation as in Example 1 was performed except that the concentrated ink was replenished to the ink tank by the number of drawn sheets as the ink density control means, and 5,000 plates were made. As a result, no defective drawing due to dust and no influence due to a change in outside temperature were observed. 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, in addition to flash fixing similar to the above,
Fixing was performed by irradiation with a halogen lamp (QIR manufactured by Ushio Inc., power consumption: 1.5 kW) and 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 adjusted to 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 by a heat roll or a halogen lamp, the fixing time could be greatly shortened 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 Ωc
m) The aluminum substrate was grounded by contact.

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 solution) 20 g Silica gel (Fuji Silysia Chemical; Sylysia # 310) 7 g Hardener 0.4 g Distillation 100 g of water was dispersed with glass beads for 10 minutes using a paint shaker.

On the other hand, when high-quality paper was used as printing paper, solid crushing failure occurred due to paper dust when printing 3,000 sheets. Therefore, an air suction pump was installed near the paper feeding unit as a paper dust prevention device. Printing was done. As a result, printing failure did not occur, and the printed matter obtained was an extremely clear image with no flying or blurring even after 5,000 sheets were passed. However, after 5,000 sheets were passed, an elongation of 0.1 mm was observed in the longitudinal direction of the A3 size image.

Example 5 Instead 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. 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) at the time of 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 sides 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 applied as a coating amount of 15 g / m2.
^An image receiving layer was provided so as to obtain a plate material of 2.

Coating for conductive layer; carbon black (30
% Aqueous solution) 5.4 parts, clay (50% aqueous solution) 54.6
Parts, SBR latex (solid content 50%, Tg 25 ° C) 3
Six parts and 4 parts of a melamine resin (solid content 80%, Sumiretz Resin SR-13) were mixed, and water was added so that the total solid content was 25% to obtain a paint.

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

[0105]

Embedded image

The obtained printed matter was a very clear image with no skipping or blurring in the printed image even when 5,000 sheets were passed.

[0107]

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.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram schematically illustrating 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 schematic configuration diagram illustrating an example of a head provided in an inkjet recording apparatus used in the present invention.

FIG. 4 is a schematic cross-sectional view of the vicinity of an ink ejection unit in FIG. 3;

FIG. 5 is a schematic cross-sectional view of an example of another head provided in the ink jet recording apparatus used in the present invention, in the vicinity of an ink ejection section.

FIG. 6 is a schematic front view of the vicinity of an ink ejection unit in FIG. 5;

FIG. 7 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. 8 is a schematic configuration diagram of a head obtained by removing a regulating plate from the head of FIG. 7;

FIG. 9 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. 10 is an overall configuration diagram schematically showing an on-press drawing four-color single-sided lithographic printing press as an example of a multicolor printing machine used in the present invention.

[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 discharge apparatus 9 Plate material (printing plate) 10) Dust removing device 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 Discharge head 221 Upper unit 222 Lower unit 22a Discharge slit 22b Discharge Electrode 23 Oil-based ink 24 Ink supply unit 25 Ink tank 26 Ink supply device 27 Stirring device 28 Ink temperature management unit 29 Ink density control unit 30 Encoder 31 Head separation / attachment device 32 Head sub-scanning unit 33 First insulating substrate 34 First Second insulating substrate 35 Slope of second insulating substrate 36 Top view of second insulating base material 37 Ink flow path 38 Ink recovery path 39 Backing 40 Groove 41 Head body 42, 42 'Meniscus regulating plate 43 Ink groove 44 Partition wall 45, 45' Ejection section 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 partition wall upper end 56 guide protrusion P printing paper

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuo Ishii 4,000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Inside Fujisha Shin Film Co., Ltd. In-house F term (Reference) 2C034 AA12 BA02 2H084 AA25 AA38 AE05 BB02 BB04 BB16 CC05 2H113 AA01 AA05 BA05 BB02 BB22 BC02 DA04 DA24 DA25 DA53 EA27 FA50 4J039 AB08 AB11 AD01 AD03 AD04 AD05 AD13 AD13 AD09 AD09 AD09 AD08 AD19 AD22 AD23 AE01 AE02 AE04 AE05 AE06 AE08 AE11 BC01 BC02 BC03 BE12 CA07 DA02 EA41 EA42 EA44 GA24

Claims (17)

[Claims] 1. A plate material is mounted on a plate cylinder of a printing press, an image is formed directly on the plate material based on a signal of image data to form a printing plate, and the printing plate is used in that state. In an on-press lithographic printing method for performing lithographic printing, an on-press lithographic printing method is characterized in that an image is formed on the plate material by an ink-jet method in which an oil-based ink is discharged using an electrostatic field. 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. A direct 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, and a lithographic printing plate on which an image is formed by the direct image forming means. An on-press lithographic printing apparatus comprising: a lithographic printing means for performing printing; wherein the direct image forming means is an ink jet lithographic apparatus for discharging oil-based ink using an electrostatic field. . Wherein said oil-based ink, the specific electrical resistance of 10 ⁹
4. The on-press lithographic printing apparatus according to claim 3, 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 Ωcm and not more than 3.5. 5. The on-press lithographic printing apparatus according to claim 3, wherein the direct image forming means includes a fixing device for the ink. 6. A plate material surface dust removing means for removing dust existing on the plate material surface before and / or during drawing on the plate material, wherein the direct image forming means is provided. 3
An on-press lithographic printing apparatus according to any one of claims 1 to 5. 7. The image forming apparatus according to claim 3, wherein at the time of drawing on said plate material, said direct image forming means performs main scanning by rotating a plate cylinder on which said plate material is mounted. 2. The on-press lithographic printing apparatus according to claim 1. 8. The ink-jet drawing apparatus includes a single head or a multi-head, and performs sub-scanning by moving the recording head in the axial direction of the plate cylinder when drawing on the plate material. An on-press lithographic printing apparatus according to claim 7. 9. The on-press lithographic printing apparatus according to claim 7, wherein the inkjet drawing apparatus includes a full line head having a length substantially equal to a width of the plate cylinder. 10. 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. . 11. The on-press lithographic printing apparatus according to claim 10, further comprising an ink collecting unit for collecting ink from the recording head, wherein the ink is circulated by the ink supply unit and the ink collecting unit. 12. The on-press lithographic printing apparatus according to claim 3, further comprising an ink stirring means in an ink tank storing the oil-based ink. 13. The 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. 14. An apparatus according to claim 3, further comprising an ink density control unit for controlling an ink density of said ink.
An on-press lithographic printing apparatus according to claim 13. 15. The recording apparatus according to claim 1, wherein the ink jet drawing apparatus causes the recording head to approach the plate cylinder when drawing on the plate material, and separates the recording head 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 14, further comprising contact means. 16. The apparatus according to claim 3, wherein said direct image forming means includes a print head cleaning means for cleaning said print head at least after the completion of plate making. Top drawing lithographic printing machine. 17. The on-press drawing according to claim 3, wherein said lithographic printing means includes paper dust removing means for removing paper dust generated during lithographic printing. Lithographic printing equipment.