JP2001260307A - Method and apparatus for on-press imaging lithographic printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for on-press imaging lithographic printing capable of corresponding to a digital operation without necessity of developing and to provide a method and an apparatus for on-press imaging lithographic printing capable of printing many printed products of a clear image of high quality by a low-cost apparatus and a simple method by eliminating a float between a plate material and a plate cylinder. SOLUTION: The method for on-press imaging lithographic printing comprises the steps of mounting the plate material 9 on the plate cylinder 11 of a printer, forming an image directly by an ink jet method for discharging an oily ink from a recording head by utilizing an electrostatic field based on a signal of image data on the material 9 to form a press plate, using the plate in its state, and subsequently lithographic printing the image. The method further comprises the steps of monitoring a distance between a surface of the plate material and the head after mounting the cylinder 1 on the material 9, and regulating the distance when the distance is out of a predetermined value.

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, the image is formed with wax, so that the mechanical strength of the image area 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.
Second, by adjusting the distance between the plate material surface and the recording head, an inexpensive apparatus and a simple method, an on-press drawing lithographic printing method capable of printing a large number of clear, high-quality images on a printing machine, and An object of the present invention is to provide an on-press lithographic printing apparatus.

[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; Based on the above signal, a printing plate is created by directly forming an image by an ink jet method in which an oil-based ink is ejected from a recording head using an electrostatic field, and a lithographic printing is continuously performed using the printing plate in that state. In the on-press lithographic printing method to be performed, after the plate material is mounted on the plate cylinder, a distance between the surface of the plate material and the recording head is monitored, and the distance is adjusted if the distance deviates from a predetermined value. It is characterized by the following. In the on-press drawing lithographic printing method according to claim 2, the plate material is brought into close contact with the plate cylinder by pressing the plate material mounted on the plate cylinder with a roller to adjust the distance between the plate material and the recording head. It is characterized by doing. The on-press lithographic printing method according to claim 3, wherein the oil-based ink is solid and hydrophobic resin particles at least at room temperature in a non-aqueous solvent having a specific electric resistance of 10 ⁹ Ωcm or more and a dielectric constant of 3.5 or less. Are dispersed. According to a fourth aspect of the present invention, there is provided an on-press lithographic printing apparatus, comprising: an image forming means for forming an image directly on a plate material mounted on a plate cylinder of a printing press based on a signal of image data; Planographic printing means for performing lithographic printing with a printing plate, wherein the image forming means is an on-press drawing lithographic printing apparatus which is an inkjet drawing apparatus including a recording head for discharging oil-based ink using an electrostatic field, A distance monitoring means for monitoring a distance between the surface of the plate material mounted on the plate cylinder and the recording head is provided.
6. An on-press lithographic printing apparatus according to claim 5, further comprising distance adjusting means for adjusting a distance between a surface of said plate material mounted on said plate cylinder and said recording head, and a monitoring result of said distance monitoring means. The distance adjusting means is operated in accordance with According to a sixth aspect of the present invention, the distance adjusting means is a pressing means for bringing the plate material on the plate cylinder into close contact with the plate cylinder. 8. The on-press lithographic printing apparatus according to claim 7, 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. An on-press lithographic printing apparatus according to claim 8, wherein the image forming means includes a fixing device for the ink. According to a ninth aspect of the present invention, in the on-press lithographic printing apparatus, the image forming unit performs main scanning by rotating a plate cylinder on which the plate material is mounted when drawing on the plate material. The on-press lithographic printing apparatus according to claim 10, wherein the recording head comprises a single-channel head or a multi-channel head, and the recording head moves in the axial direction of the plate cylinder when drawing on the plate material. A sub-scan is performed. An on-press lithographic printing apparatus according to claim 11, wherein the recording head comprises a full line head having a length substantially equal to the width of the plate cylinder. According to a twelfth aspect of the present invention, there is provided the on-press lithographic printing apparatus, wherein the inkjet drawing apparatus includes an ink supply unit for supplying ink to the recording head. According to a thirteenth aspect of the present invention, there is provided an on-press lithographic printing apparatus comprising an ink collecting means for collecting ink from the recording head, wherein the ink supply means and the ink collecting means circulate ink. According to a fourteenth 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. An on-press lithographic printing apparatus according to a fifteenth aspect is characterized in that an ink temperature control means for controlling the temperature of ink is provided in an ink tank storing the oil-based ink. An on-press lithographic printing apparatus according to a sixteenth aspect is characterized in that the lithographic printing apparatus further comprises an ink density control unit for controlling the ink density of the ink. The on-press lithographic printing apparatus according to claim 17, 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 18, wherein the image forming means includes a recording head cleaning means for cleaning the recording head at least after the completion of plate making. The lithographic printing apparatus according to the nineteenth aspect 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 relates to a method for forming an image on a plate material (printing original plate) provided on a plate cylinder of a printing press by an inkjet method in which an oil-based ink is ejected from a recording head by an electrostatic field. Characterized in that the distance is controlled to be constant.

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 the present inkjet method, the size of the ejected ink droplet is determined by the size of the tip of the ejection electrode or the shape of the electric field, and a small ink droplet can be obtained without reducing the ejection nozzle diameter or slit width. By controlling the electric field shape condition, the dot diameter on the plate material can be controlled. Therefore, according to the planographic printing method of 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 image printed matter.

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 ejected onto the plate material 9 to form an image.

Further, the printing apparatus 1 is provided with a dampening water supply device 3 for supplying dampening water to a hydrophilic portion (non-image portion) on the printing plate 9. FIG. 1 shows a Molton water supply system as a representative example of the dampening water supply device 3. 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. Further, a plate surface desensitizing device 6 may be provided for the purpose of enhancing the hydrophilicity of the surface of the plate material 9. The printing apparatus 1 includes a plate material surface dust removing unit 10 that removes 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 the plate material 9 onto the plate cylinder 11 and an automatic plate discharging device 8 for automatically removing the plate material 9 after printing may be provided. As a printing press having this device, which is known as an auxiliary device of a printing press, for example, Hamada VS34A, B452A (Hamada Printing Machinery Co., Ltd.), Toko 8000 PFA (Tokyo Aviation Instruments), Ryobi 3200ACD, 3200 PFA
(Ryobi Imagisk), AMSIS Multi
i5150FA (Am Japan), Oliver 26
6EPZ (Sakurai Graphic Systems Co., Ltd.) and Shinohara 66IV / IVP (Shinohara Shoji Co., Ltd.). 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. Further, a paper dust generation preventing device (paper dust removing means) 15 may be provided in the vicinity of the impression cylinder 13, so that the paper dust can be prevented 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.

The printing apparatus 1 has an optical gap detecting device 20 for measuring the distance between the printing material 9 and the recording head when the printing material 9 is mounted on the printing drum 11. As the optical gap detecting device 20, for example, a laser distance measuring device or the like can be used. Further, the printing apparatus 1 has a pressing roller 48 that is driven and controlled in accordance with an output from the optical gap detecting device 20. The pressing roller 48 is, for example, a roller whose surface is subjected to Teflon processing, and can be controlled to be in a pressed state or a non-pressed state with respect to the plate cylinder 11 on the downstream side of the optical gap detection device 20. It is arranged in.

The image data arithmetic control unit 21 receives image data from an image scanner, a magnetic disk device, an image data transmission device, etc., performs color separation, 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 section 21 controls the movement of the ink jet discharge head 22 and the discharge timing of the oil-based ink and, if necessary, the plate cylinder 11, blanket cylinder 12, impression cylinder 13 , Etc., is also controlled.

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

First, the plate material 9 is mounted on the plate cylinder 11 by using the automatic plate feeding device 7. At this time, the plate material is closely fixed on the plate cylinder by a 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 addition, as shown in FIG. 1, the pressing roller 48 is provided downstream of the plate cylinder drawing position, but may be provided upstream. Further, by providing a means for preventing the bottom of the plate from contacting the ink supply roller in the process of fixing the plate, it is possible to prevent the plate surface from being stained and to reduce waste paper. Specifically, a pressing roller, a guide, electrostatic attraction, or the like is effective.

Image data from a magnetic disk device or the like
The image data 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 discharge head 22, a single-channel head, a multi-channel head, or a full-line head can be used, and the main scanning is performed by the rotation of the plate cylinder 11. In the case of a multi-channel head having a plurality of discharge units or a full line head, the arrangement of the discharge units is set in the axial direction. Further, in the case of a single-channel head or a multi-channel head, the image data arithmetic control unit 21 controls the head 22 for each rotation of the plate cylinder 11.
Is moved in the 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 unit 10 are also provided with a separating / contacting unit together with the ejection head 22, the ink supply unit 24, and the head sub-scanning unit 32 so that they can be retracted.

This separation / contact means operates so that the recording head is separated 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 and solvent fixing can be used. In the heat fixing, irradiation with an infrared lamp, a halogen lamp, a xenon flash lamp, hot air fixing using a heater, and heat roll fixing are generally used. In this case, 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. Flash fixing using a xenon lamp or the like is known as a method for fixing electrophotographic toner, and has an advantage that fixing can be performed in a short time. 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. Note that 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, the dampening solution supply device 3, the printing ink supply device 4, and the blanket cylinder 12 hold the plate material 9 on the plate cylinder. It is desirable to keep it from touching.

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.

In addition, the printing apparatus has an ink density control unit 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, by the output signal, When the management is performed based on the number of drawn sheets, the supply of liquid from a replenishment concentrated ink tank or a diluted ink carrier tank (not shown) to the ink tank is controlled based on the number of plate making and the frequency.

As described above, the image data calculation control unit 21 calculates the input image data,
1. In addition to moving the head by the head sub-scanning means 32, a timing pulse from the encoder 30 installed on the plate cylinder is fetched, and the head is driven according to the timing pulse. Thereby, the positional accuracy in the sub-scanning direction can be improved. In addition, the position accuracy in the sub-scanning direction can be enhanced by using a high-precision 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. Is applied, the photoresist is exposed through a mask having a predetermined electrode pattern, and is developed to form a photoresist pattern of the discharge electrode 22b. Then, a method of etching or mechanically removing the photoresist pattern, or a method of removing them is used. It is formed by a known method such as a combined method.

In the head 22, a voltage is applied to the ejection electrode 22b according to a digital signal of 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 such as applied voltage and ink physical properties, but are usually used in a range of a tip width of 5 to 100 μm. For example, a discharge electrode 22b having a 20 μm wide tip is used, and the distance between the discharge electrode 22b and the plate cylinder 11 serving as a counter electrode is set to 1.0 mm.
A dot of 40 μm can be formed on the plate material 9 by applying a voltage of 1 millisecond.

FIGS. 5 and 6 are a schematic cross-sectional view and a schematic front view, respectively, of the vicinity of the ink discharge portion of another 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 section 21. When recording, the ink on the ejection electrode is ejected by applying a voltage to the ejection electrode based on the image information. Drawing is performed on a plate material (not shown) arranged oppositely. The direction opposite to the ink droplet ejection direction of the ink inflow path 37 is connected to an ink feeding unit of an ink supply device (not shown). The second insulating substrate 3
A backing 39 is provided on the surface opposite to the ejection electrode forming surface of No. 4 so as to be spaced apart and opposed, and an ink recovery path 38 is provided between the two. The space of the ink recovery path 38 is 0.1
mm or more is desirable. The reason that this space is preferable in the above range is that if the space is too narrow, it becomes difficult to collect the ink, which may cause ink leakage. The ink recovery path 38 is connected to an ink recovery unit of an ink supply device (not shown).

When a uniform ink flow on the discharge section is required, a groove 40 may be provided between the discharge section and the ink recovery path. FIG. 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
A plurality of inks 0 are arranged in the arrangement direction of the ejection electrodes 22b, and a certain amount of ink near the tip of the ejection electrode is guided from the opening on the ejection electrode 22b side by a capillary force according to the opening diameter. Is discharged to the ink recovery path 38. 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 to 300 μm.
It is in the range of μm. Further, a necessary number of grooves 40 are provided so that a uniform ink flow can be formed over the entire surface of the head.

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

FIGS. 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 body 41 is provided with a plurality of ink grooves 43 for circulating ink perpendicular to the edge of the head body. The shape of the ink groove 43 may be set in a range where the capillary force acts so that a uniform ink flow can be formed, and 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 'are formed. Each groove 51, 51 '
Is preferably in the range of 10 to 200 μm in width and 10 to 300 μm in depth, and the discharge electrode 22b is formed entirely or partially inside. As described above, by forming the plurality of grooves 51, 51 'on one surface of the support members 50, 50', a plurality of rectangular partition walls 52 are provided between the grooves 51.
Is inevitably provided. The support members 50 and 50 'are combined so that the surfaces on which the grooves 51 and 51' are not formed face each other. That is, the ejection head 22 has a plurality of grooves on the outer peripheral surface for flowing ink. The grooves 51, 51 ′ formed in the support members 50, 50 ′ are connected in a one-to-one correspondence via a rectangular portion 54 of the discharge head 22. It is retracted from the upper end 53 of the head 22 by a predetermined distance (50 to 500 μm). That is, on both sides of each rectangular portion 54, the upper end 55 of each partition 52 of each support member 50, 50 ′ is provided so as to protrude 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, if 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, an on-press drawing multicolor single-sided lithographic printing apparatus will be described as a specific example of the present invention. 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 plurality of color plates are 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 multicolor 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 material (printing plate) used in the present invention will be described. Examples of the printing original plate include metal plates such as aluminum and chrome-plated steel plates. In particular, an aluminum plate having excellent surface water retention and abrasion resistance by graining and anodizing is preferable. As an inexpensive plate material, a plate material provided with an image receiving layer on a water-resistant support such as water-resistant paper, plastic film, or paper laminated with plastic can be used. The thickness of the provided image receiving layer is suitably in the range of 5 to 30 μm.

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

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

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

The zinc oxide used in the present invention can be prepared, for example, as described in “Pigment Handbook”, edited by Japan Pigment Technical Association, page 319, 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 the binder include styrene copolymers, methacrylate copolymers, acrylate copolymers, vinyl acetate copolymers, polyvinyl butyral, alkyd resins, epoxy resins, and epoxy esters. Resins, polyester resins, polyurethane resins, and the like. These resins may be used alone or in combination of two or more. The content of the resin in the image receiving layer was represented by a weight ratio of resin / zinc oxide of 9/91.
It is preferably set to ２０20/80.

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

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

The specific electric resistance used in the present invention is 10 ⁹ Ωcm.
As the non-aqueous solvent having a dielectric constant of 3.5 or less, preferably a linear or branched aliphatic hydrocarbon, alicyclic hydrocarbon, or aromatic hydrocarbon, and a halogen-substituted hydrocarbon thereof are used. is there. For example, hexane, heptane, octane, isooctane, decane, isodecane, decalin, nonane, dodecane, isododecane, cyclohexane, cyclooctane, cyclodecane, benzene, toluene, xylene, mesitylene, isoper C, isoper E, isoper G, isoper H, isoper L (Isoper; Exxon's trade name), Shellsol 70, Shellsol 71 (Shellsol; Shell Oil's trade name), Amsco OMS, Amsco 460 solvent (Amsco; Spirits' trade name), silicone oil, etc. Alternatively, they are mixed and used. The upper limit of the specific electric resistance of such a non-aqueous solvent is about 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 in the above range is that when the electric resistance is low, the concentration of the resin particles and the like hardly occurs, and sufficient printing durability cannot be obtained. The reason for setting the above range is that when the dielectric constant is increased, the electric field is relaxed due to the polarization of the solvent, whereby the ejection of the ink tends to be deteriorated.

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

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

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

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

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

The oil-based ink used in the present invention preferably contains a coloring material as a coloring component together with the above-mentioned dispersed resin particles, for example, for plate inspection of a plate after plate making.
As the 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, cobalt green, ultramarine blue, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment , Quinacridone-based pigments, isoindolinone-based pigments, dioxazine-based pigments, threne-based pigments, perylene-based pigments, perinone-based pigments, thioindigo-based pigments, quinophthalone-based pigments, metal complex pigments, and other known pigments. It can be used without.

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

These coloring materials may be dispersed in a non-aqueous solvent as dispersed particles in the non-aqueous solvent separately from the dispersed resin particles, or may be contained in the dispersed resin particles. In the case of containing, pigments and the like are generally coated with the resin material of the dispersed resin particles to obtain resin-coated particles, and dyes and the like are formed 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 further including the colored particles, preferably have an average particle diameter of 0.05 μm to 5 μm. More preferably, it is 0.1 μm to 1.0 μm. This particle size is CAPA-
500 (trade name, manufactured by Horiba, Ltd.).

The non-aqueous 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 Kenji Ueki, “Flow and paint dispersion of paint”, Kyoritsu Shuppan (1971), Solomon “ Coating Science "Hirokawa Shoten (1969), Yuji Harasaki" Coating Engineering "Asakura Shoten (1971), Yuji Harasaki" Basic Science of Coatings "Maki Shoten (1977), etc.

Examples of the polymerization granulation method include a conventionally known non-aqueous dispersion polymerization method. Specifically, the latest technology of 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).

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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 include a hydrogen atom, a halogen atom (eg, a chlorine atom or a bromine atom), a cyano group, an alkyl group having 1 to 3 carbon atoms (eg, methyl Group, ethyl group, propyl group, etc.),-
COO-Z ₁ or —CH ₂ COO-Z ₁ [Z ₁ is an optionally substituted hydrocarbon group having 22 or less carbon atoms (eg, an alkyl group, an alkenyl group, an aralkyl group, an alicyclic group, an aryl group Etc.).

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

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

The proportion of the polymer component represented by the general formula (I) in the dispersion polymer is preferably at least 50% by weight, more preferably at least 60% by weight. Specific examples of these dispersion polymers 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 resin (P) particles are prepared as a dispersion (latex) or the like, the dispersion polymer is preferably added in advance during polymerization. When the dispersion polymer is used, the addition amount is 1 to 50 with respect to the resin for particles (P).
% By weight.

The dispersed resin particles and colored particles (or coloring material particles) in the oil-based ink of the present invention are preferably positively or negatively charged electro-detectable particles. In order to impart an electric detecting property to these particles, it can be achieved by appropriately utilizing a technique of a developer for wet electrophotography. Specifically, the above-mentioned “Recent development and commercialization of electrophotographic development systems and toner materials”
139-148, edited by the Society of Electrophotography, "Basics and Application of Electrophotographic Technology", 497-505 (Corona Co., 1988), Yuji Harazaki, "Electrophotography" 16 (No. 2), 44 (1977), etc. This is performed by using an electric detection material such as a charge control agent described in (1) and other additives.

Specifically, for example, British Patent No. 8934
No. 29, No. 934038, No. 11222397,
U.S. Patent Nos. 3,900,412 and 4,606,899,
JP-A-60-179751, JP-A-60-185963
And JP-A-2-13965. The charge 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 specific electric resistance of the ink from which the dispersed particles have been removed is lower than 10 ⁹ Ωcm, it becomes difficult to obtain a high-quality continuous tone image. desirable.

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

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

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A part of the white dispersion was centrifuged (rotation speed: 1 × 10 ⁴ rpm, rotation time: 60 minutes), and the precipitated resin particles were collected and dried. 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.

Examples 1 to 3 First, oil-based inks were 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 for ink particles, 2.5 g of the above nigrosine dispersion, FOC-1400 (manufactured by Nissan Chemical Co., Ltd., Tetradecyl Alcohol) and octene-half-maleic acid hexadecylamide copolymer 0.1 g.
08 g was 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 multi-channel head 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 precipitation 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 the plate material, a paper plate material provided with a hydrophilic image receiving layer on the surface shown below was used. Basis weight 10 as substrate
0 g / m ² high quality paper, kaolin on the surface of the substrate,
A dispersion A prepared as described below is applied on a paper support provided with a water-resistant layer containing a polyvinyl alcohol, an SBR latex and a resin component of a melamine resin as main components to obtain a coating amount of 6 g / m ² after drying. Thus, a paper plate material was provided with an image receiving layer.

Dispersion A Gelatin (Wako Pure Chemicals first grade) 3 g Colloidal silica (Nissan Chemical; Snowtex C, 20% aqueous dispersion) 20 g Silica gel (Fuji Silysia Chemical; Sylysia # 310) 7 g Hardener 0 4 g of 100 g of distilled water was dispersed with glass beads for 10 minutes using a paint shaker.

The plate material was set in an automatic plate feeder, and the plate material was mechanically mounted on a plate cylinder. Separate the dampening water supply device, the printing ink supply device, and the blanket cylinder so that they do not come into contact with the plate material, remove the dust on the plate material surface by suctioning with an air pump, and then move the discharge head close to the plate material to the drawing position and print. The image data to be transmitted was transmitted to the image data calculation control unit, and the 64-channel ejection head was moved while rotating the plate cylinder, thereby discharging oil-based ink onto the plate to form an image. At this time, the tip width of the ejection electrode of the ink jet head was 10 μm, and the distance between the plate material and the plate cylinder, that is, the lift was 0.1 mm according to the output from the optical gap detection device.
In the above case, before drawing, press plate roller (made of Teflon)
Was activated. Further, the distance between the head and the plate material was controlled to be always 1 mm ± 0.03 mm during drawing. A voltage of 2.5 kV is constantly applied as a bias voltage, and when performing ejection, a pulse voltage of 500 V is further superimposed, and the pulse voltage is reduced from 0.2 milliseconds to 0.0.
Writing was performed while changing the dot area by changing the dot area in 256 steps within a range of 5 milliseconds. In the first embodiment, when the plate material is lifted by 0.11 mm when the plate material is mounted on the plate cylinder, in the second embodiment, the plate material floats by 0.3 mm.
In the case of 0 mm, and in Example 3, the lifting of the plate material was 1.50 mm, and the damage of the head and the drawing property after being pressed by the pressing roller 48 according to the present invention were examined. Table 1 shows the results.

[0095]

[Table 1]

In Examples 1 to 3, the lifting was reduced to 0.03 mm or less by the pressing roller, and no damage to the head and no defective drawing due to a poor distance between the plate material and the head were observed after drawing. No image deterioration due to a change in the dot diameter was observed at all even by the change and the increase in the number of plate making, and good plate making was possible.

Further, a heat roller (300 W halogen type Teflon (registered trademark) sealed silicone rubber roller) is heated and pressurized by fixing (pressure 3 kgf / cm).
² (29.4 N / cm ² )) A printing plate was prepared by strengthening the image. Next, in order to protect the ink jet discharge head, the ink jet recording apparatus is retracted by 50 mm from the position in proximity to the plate cylinder together with the sub-scanning means, and then, as described above, the normal lithographic printing method is used to coat the printing coated paper. Printing was done. That is, a printing image is formed by applying a printing ink and a fountain solution to the printing plate, and the printing ink image is transferred onto a blanket cylinder rotating with the plate cylinder, and then,
The printing ink image on the blanket cylinder was transferred onto the coated printing paper passing between the blanket cylinder and the impression cylinder.

The obtained printed matter was an extremely clear image without any skipping or blurring in the printed image even after passing 5,000 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.

Comparative Examples A and B Plate making and printing were performed in the same manner as in Example 1 except that the pressing roller was not operated. In Comparative Example A, the drawing property was degraded with the lift between the plate material and the plate cylinder remaining at 0.11 mm. In Comparative Example B, the lift was 0.5
It was even larger at 0 mm, and the drawing performance was further deteriorated, and the head was damaged.

The quality of the drawing properties in the table was judged by observing the fine lines, characters and halftone dots after plate making, and observing the thickening and thinning with a magnifier of 20 times.

[Examples 4 to 6] A dampening solution supply roller used at the time of printing was used in place of the plate material pressing roller.
The operation was the same as in Example 1 except that the print was dried with a heat lamp (300 W halogen lamp) before drawing when the dampening solution supply roller was operated. In Example 4, when the plate material was mounted on the plate cylinder, the lift of the plate material was 0.10.
mm, in Example 5, a case where the plate material was lifted by 0.31 mm, and in Example 6, a case where the plate material was lifted by 1.30 mm, respectively, according to the present invention. After the plate was pressed by the supply roller and the plate surface was dried by the heat lamp, the damage of the head and the drawing property were verified. In Examples 4 to 6, the lift was reduced to 0.02 mm or less due to the pressure of the dampening solution supply roller, and after drawing, no damage to the head, no defective drawing due to a poor distance between the plate material and the head, and the like were not observed at all. No image deterioration due to changes in dot diameter, etc., was observed even with changes in temperature and the number of plate making.
Good plate making was possible. The obtained printed matter was an extremely clear image without any jump or blur in the printed image even after 5,000 sheets were passed. Further, for 10 minutes after the completion of plate making, Isopar G is supplied to the head, and Isopar G is supplied from the head opening.
After cleaning by dripping, the head is stored in the cover filled with the vapor of Isopar G,
Good prints could be made for three months without the need for maintenance work.

[0102]

[Table 2]

[0103]

According to the present invention, the distance between the surface of the plate material and the recording head is monitored, and when the distance deviates from a predetermined value, the plate material mounted on the plate cylinder is pressed by a roller.
The floating between the plate material and the plate cylinder can be eliminated, so that 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 discharging apparatus 9 Plate material (printing plate) 10) Dust removing means 11 Plate cylinder 12 Blanket cylinder 13 Impression cylinder 14 Blanket cleaning device 14 'Impression cylinder cleaning device 15 Paper dust generation prevention device 20 Optical gap detection device 21 Image data calculation control unit 22 Discharge head 221 Upper unit 222 Lower part Unit 22a Discharge slit 22b Discharge electrode 23 Oil-based ink 24 Ink supply unit 25 Ink tank 26 Ink supply device 27 Stirring unit 28 Ink temperature management unit 29 Ink density control unit 30 Encoder 31 Head separation unit 32 Head sub-scanning unit 33 First Insulating base material 34 Second insulating base material 35 Slope of Second Insulating Base 36 Upper Surface of Second Insulating Base 37 Ink Inlet 38 Ink Recovery 39 Backing 40 Groove 41 Head Body 42, 42 ′ Meniscus Regulated Plate 43 Ink Groove 44 Partition 45 , 45 'discharge section 46 partition wall 47 partition end section 48 press roller 50, 50' support member 51, 51 'groove 52 partition wall 53 upper end section 54 rectangular section 55 partition wall upper end 56 guide projection P printing paper

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B41J 25/308 (72) Inventor Eiichi Kato 4000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Inside Fujisha Shin Film Co., Ltd. F term (reference) 2C056 EA07 EA16 EA24 EA27 EA28 EB20 EB30 EC19 EC23 EC44 EC45 EC46 EC53 FA07 FA13 FB01 HA12 HA46 JB15 JC06 JC13 KB16 2C064 CC02 DD07 DD11 2H084 AA25 AA38 AE05 BB04 BB16 CC05

Claims (19)

[Claims] An image is directly mounted on a plate cylinder of a printing press by an ink jet method in which an oil-based ink is ejected from a recording head by using an electrostatic field based on a signal of image data. In the on-press drawing lithographic printing method for forming a printing plate by forming and subsequently performing lithographic printing using the printing plate in that state, after mounting the plate material on a plate cylinder, the surface of the plate material and An on-press lithographic printing method comprising monitoring a distance between the recording heads and adjusting the distance when the distance deviates from a predetermined value. 2. The method according to claim 1, wherein the plate material is brought into close contact with the plate cylinder by pressing the plate material mounted on the plate cylinder with a roller to adjust the distance between the plate material and the recording head. 2. The on-press lithographic printing method according to 1. 3. The method according to claim 1, wherein the oil-based ink has a specific electric resistance value of 10.
The on-press drawing according to claim 1 or 2, wherein solid and hydrophobic resin particles are dispersed at least at room temperature in a non-aqueous solvent having a dielectric constant of ⁹ Ωcm or more and a dielectric constant of 3.5 or less. Lithographic printing method. 4. An image forming means for forming an image directly on a plate material mounted on a plate cylinder of a printing press based on a signal of image data, and lithographic printing is performed by a printing plate on which an image is formed by the image forming means. Lithographic printing means, wherein the image forming means comprises a recording head for discharging an oil-based ink using an electrostatic field. An on-press lithographic printing apparatus comprising a distance monitoring means for monitoring a distance between a surface of a material and the recording head. 5. A distance adjusting means for adjusting a distance between a surface of the plate material mounted on the plate cylinder and the recording head, wherein the distance adjusting means is provided in accordance with a result of monitoring by the distance monitoring means. The on-press lithographic printing apparatus according to claim 4, wherein the lithographic printing apparatus is operated. 6. An on-press lithographic printing apparatus according to claim 5, wherein said distance adjusting means is a pressing means for bringing a plate material on said plate cylinder into close contact with said plate cylinder. 7. The ink according to claim 6, wherein the oil-based ink has a specific electric resistance of 10 ^9.
7. The on-press lithographic printing plate according to claim 4, 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. Printing device. 8. An on-press lithographic printing apparatus according to claim 4, wherein said image forming means includes a fixing device for said ink. 9. The image forming apparatus according to claim 4, wherein at the time of drawing on said plate material, said image forming means performs main scanning by rotating a plate cylinder on which said plate material is mounted. 1
Item. 10. The recording head comprises a single-channel head or a multi-channel head, and performs sub-scanning by moving the recording head in the axial direction of the plate cylinder when drawing on the plate material. Claim 9
The on-press lithographic printing apparatus as described in the above. 11. An on-press lithographic printing apparatus according to claim 9, wherein said recording head comprises a full line head having a length substantially equal to a width of the plate cylinder. 12. The on-press lithographic printing apparatus according to claim 4, wherein the inkjet drawing apparatus includes an ink supply unit that supplies ink to the recording head. . 13. The on-press lithographic printing apparatus according to claim 12, 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. 14. The on-press lithographic printing apparatus according to claim 4, further comprising an ink agitating means in an ink tank for storing the oil-based ink. 15. The on-press drawing according to claim 4, 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. 16. An apparatus according to claim 4, further comprising an ink density control means for controlling an ink density of said ink.
An on-press lithographic printing apparatus according to claim 15. 17. The printing apparatus according to claim 17, 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 4 to 16, further comprising contact means. 18. The image forming apparatus according to claim 4, wherein said image forming means includes a print head cleaning means for cleaning said print head at least after the completion of plate making.
The on-press lithographic printing apparatus according to any one of claims 17 to 17. 19. The on-press drawing according to claim 4, wherein said lithographic printing means includes paper dust removing means for removing paper dust generated during lithographic printing. Lithographic printing equipment.