JP2003513824A - Fluid for plate making and how to use the fluid - Google Patents

Abstract

  (57) [Summary] A simple and inexpensive way to produce offset lithographic printing plates in a process using a novel inkjet fluid that can be easily dried on uncoated printing plates, while providing excellent jettability with high consistency and quality The direct computer-to-plate (CTP) method. The inkjet fluid has a preselected viscosity and comprises a two-phase emulsion system, ie, a lipophilic internal phase and a continuous aqueous dispersion medium. By adjusting the viscosity of the ink jet fluid, it is possible to control the size of the dots of the fluid deposited on the printing surface, resulting in high quality and toughness even after multiple runs of the offset printing press. A printed image is provided.

Description

Detailed Description of the Invention

    (Field of the invention)

The present invention relates generally to the production of printing plates using the computer-to-plate (CTP) method with inkjet printing, and more particularly to novel inkjet marking fluids and offset lithographic printing. Printing plate (offset litho
Direct CTP creation method for graphic printing plates).

BACKGROUND OF THE INVENTION The offset lithographic printing method is mainly used because a printing plate can be produced relatively easily.
It has been regarded as a popular printing method for many years. At present, the most widely used plate-making method still utilizes a specially manufactured masking film in which a pre-sensitized printing blank is selectively cured or softened by exposure to UV light-according to the chemistry of the plate- Has become a way to do. The plate is then subjected to a development process during which the more soluble areas of the plate are washed away. For a detailed description of a typical system and the plates used, see Bob Thompson (Bob
Thompson) book title "Printing Materials: Science and Technology:
Science and Technology) "(Laser Head, Surrey, UK)
Leatherhead], Pira Int., 1998), Chapter 20.

In recent years, various considerations have emerged that address the benefits of modifying what has heretofore been generally accepted. With the advent of computers, printing information has been digitally processed, and it has therefore become desirable to use this digital information as directly as possible in plate making. One obvious way would be to eliminate the masking film. Not only are these films a source of expense, but the most widely used films are based on silver chemistry, so exposure and handling of the films must be done in a light-excluded environment. In addition, exposed films must be processed with unstable, cumbersome, and environmentally problematic chemical solutions. One answer can be found in computer-to-plate (CTP) systems, which results in offset litho plates.
The graphic plate is imaged directly by a light source that is modulated to correspond to digital information from the computer. Thus, the film intermediate material is omitted altogether. Such printing plates generally still require solution processing, although attempts have been made to develop an unprocessed CTP system. A more detailed description of the subject of the CTP system can be found in the above cited book (Thompson, supra), Chapter 21.

US Pat. No. 5,339,737 to Lewis et al. Describes a method for making unprocessed offset lithographic printing plates in which the upper layer or layers of the plate are removed by ablation. Has been done. The upper layer is a waterless printing plate (wa
It is either oleophobic for terless plates) or hydrophilic for conventional wet process printing plates. The substrate is lipophilic in both cases. Another patent similar to that described above is US Pat. No. 5,353,705 to Lewis et al., Which describes an additional layer for the second partial ablation. Yet another patent that utilizes ablation is US Pat. No. 5,487,338 to Lewis et al., Which patent involves the use of a reflective layer. All of these prior art inventions are expensive,
In addition, it requires a multi-layer printing plate that takes time to create. Further, it is more difficult to maintain a quality standard that does not vary from printing plate to printing plate. Moreover, they utilize inherently expensive laser imaging systems. Due to these disadvantages, the demands of many small to medium sized businesses are not addressed by these prior art inventions.

There is a need for a platemaking process that has the highest degree of simplicity, eliminates any chemical processing, and can be performed at the least cost for platemaking and associated equipment. This method should also be quick.

Inkjet printing is a non-impact digital printing method that allows images to be created and printed under computer control. Inkjet inks are jetted through very fine nozzles and the resulting ink droplets form an image directly on a substrate. These are two important types of inkjet method. In one method, commonly referred to as "continuous inkjet printing", a stream of ink droplets is charged and then either directly or indirectly by an electric field onto a substrate. Biased. The viscosity of the ink used in such systems is typically 2 or 3 centipoise. "Drop-on-
In a second method, commonly referred to as the “drop on demand (DOD) inkjet printing method”, the ink is supplied by the Trident Ultrajet printhead (
It is regulated by an actuator, such as a piezoelectric actuator of the type used in the Trident Ultrajet Printhead). The pressure created during operation forces the droplet through the nozzle and onto the substrate. The inks for the DOD inkjet printing method need not be conductive and their viscosities are typically 2-40 centipoise.

The prior art has shown some applications of the inkjet printing principle to the production of offset lithographic printing plates.

[0008] In US Pat. No. 4,833,486 to Zerillo, a hydrophobic solid inkjet ink--a phase change inking medium.
Also referred to as change inking medium) -contains a wax that is held at a temperature high enough to eject the ink through a DOD head. This solid phase change ink technology is described in US Pat. No. 4,390,390 to Merritt et al.
369 and 4,484,948 and U.S. Pat. No. 4,593,292 to Lewis. The substrate is
A hydrophilic offset printing plate-either paper or aluminum-on which ink is jetted to form an image. When the ink hits the plate, it immediately cools and solidifies. One problematic and significant drawback of such methods is that it is difficult to obtain a sufficiently high antiplate adhesion of the wax in the ink medium for multiple printing during lithographic printing. is there.

European Patent EP 503 owned by Nippon Paint Co.
No. 621 describes two methods. One method describes jetting ink onto a pre-sensitized printing plate, which plate then requires further processing, including a development step with a liquid developer. Another method uses a non-presensitized printing plate, the inkjet ink of which is photosensitive so that it can be cured on the plate.

European Patent EP 533168, owned by Nippon Paint Co., Ltd., describes the use of a photopolymerizable ink jet ink with an ink-absorbing layer on a lithographic printing plate surface.

[0011] European Patent EP 6972282 to Leanders, owned by Agfa, is a lipophilic reduction which allows the ink to be used in an offset printing process when it hits the plate. A two-component system is described in which one reactive component is present in the ink and the other component is present in the lithographic plate surface so as to produce a silver image.

[0012] Gerber Scientific Products (Gerber Scientific Produc
US Patent No. 5,495,80 to Gerber owned by ts, Inc)
No. 3, a coated presensitized printing plate is imaged with a UV opaque hot melt inkjet ink, which ink is used as a photomask to expose the plate. The non-exposed pre-photopolymer and the ink are subsequently removed by washing.

US Pat. No. 5,738,013 to Kellet includes the use of a reactive inkjet ink that is bound to a lithographic printing plate in a chemical reaction that is activated by radiant energy. It describes how to make a printing plate. This assumes that such inks have very good stability at room temperature, so that ink that does not pass through the inkjet nozzles is blocked.
Moreover, it is envisaged that the ink will have good reactivity at high temperatures so that it becomes insoluble with good offset plate adhesion and good lipophilicity.

Thus, there have been prior art attempts to use the inkjet method for direct imaging of printing plates, but in an attempt to provide acceptable quality and run length while maintaining reasonable costs and run times. If that is still difficult. Both water-based and solvent-based inks have the problem of spreading on a hydrophilic printing plate with high surface energy due to the properties required to eject the ink. Phase change inks have the problem that wax-like inks bond to the plate. In addition, there is a need to eliminate further liquid processing and to provide a simple platemaking process, i.e., to eliminate printing plate components and form an image directly on the printing surface of a lithographic press.

SUMMARY OF THE INVENTION Accordingly, a primary object of the present invention is to provide a simple and inexpensive method for making offset lithographic printing plates by using the inkjet method, thereby providing a computer-to-computer method of the prior art. Overcoming the disadvantages associated with the plate method. This method uses a novel inkjet fluid that can be easily dried on an uncoated lithographic printing plate while providing excellent jettability with a high degree of consistency and quality. .

[0016]   According to one preferred method of the present invention, a direct CTP preparation method of a printing plate comprising:

Providing a digital image produced by a computer system; providing an ink jet marking fluid having a preselected viscosity,
Where the marking fluid comprises a two-phase emulsion system consisting of a lipophilic internal phase and a continuous aqueous dispersion medium;

[0018]   Jetting the marking fluid onto the printing surface; and   Dry the marking fluid on the printed surface A method as described above is provided that comprises steps.

In this preferred method, the inkjet marking fluid is deposited in a pattern that is digitally defined to provide information directly from the computer to the printing plate. According to the method of the present invention, the dot size of the inkjet fluid deposited on the printing surface of an offset printing press is controlled by adjusting the viscosity of the fluid, thus relating to the quality of the image to be printed. Good control is achieved.

In another preferred method, the novel inkjet marking fluids of the present invention can be used directly in a plateless lithographic printing system to print large quantities of good quality impressions. Form a strong, stable lipophilic image.

Other features and advantages of the invention will be apparent from the more detailed description and examples.

For the purpose of better understanding the invention with respect to aspects of the invention, the accompanying drawings (
(No scale). In the accompanying drawings, like numbers indicate corresponding elements or parts throughout.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIGS. 1A, 1B and 1C, which illustrate steps in a widely used prior art method of making a plate using a pre-sensitized printing plate. 1
An example is shown.

FIG. 1A shows a film 2 containing the image 4 to be printed in negative form. The pre-sensitized printing plate 6 comprises a grained anodized aluminum substrate 8 and is coated with a photosensitive polymer layer 10 comprising a photosensitive prepolymer and a carrier resin. The film 2 is placed in emulsion-to-emulsion contact with the presensitized printing plate 6 and is flood illuminated with ultraviolet light 12 as shown in FIG. 1B. The transparent area 4 of the negative film 2 represents the image area to be printed, U
V light 12 reacts to form a hard insoluble lipophilic region 14 photopolymer layer 1
Allows transmission to zero. The black areas 5 of the negative film 2 correspond to the background areas of the print and prevent the UV light 12 from passing therethrough and thus the photosensitive layer 10
Those parts of remain in the prepolymer state. The negative film 2 is then removed, and the printing plate 6--usually with an aqueous solution of high pH in which the unpolymerized parts of the layer 10 are easily dissolved--is processed. This exposes the grained anodized surface 16 of the substrate 8 and its processed hydrophilic background region is now ready for mounting in a conventional offset lithographic press, as shown in FIG. 1C. It can be used for printing plates.

2A, 2B and 2C are enlarged views showing the steps of a simplified, infrared ablatable computer-to-plate method known in the prior art. FIG. 2A depicts an unprocessed printing plate 26 including a substrate 8 which may be, for example, aluminum; an infrared absorbing layer 22; and a hydrophilic top coating 24. In FIG. 2B, plate 26 is imaged with digitally modulated infrared radiation 28 absorbed by layer 22. The absorbed energy causes a very fast temperature rise, resulting in ablation of layer 22. This ablation removes portions of hydrophilic coating 22 as well as layer 22.
FIG. 2C shows the obtained printing plate, which is a part of the coating 24 that becomes the hydrophilic background region of the printing plate 26 and the surface 16 of the substrate 8 that becomes the lipophilic image forming part of the printing plate 26. With exposed parts of.

Turning now to FIG. 3, which illustrates a computer-to-plate inkjet printing system 3 constructed and operated in accordance with the principles of the present invention.
0 is shown. Computer 20 is used to generate a data pulse sequence 42 which energizes transducer 45. The transducer 45 emits an electrical signal that activates the piezoelectric crystal 36. The crystals 36 create a pressure wave inside the ink chamber 38, which causes the ink jet fluid 32 in the ink chamber 38 to drop through the ink jet printer nozzle 34 onto the surface 16 of a typical plate substrate 8. Inject into the flow of. The substrate 8 can be any type of substrate known to those skilled in the art in which offset lithographic printing plates are processed, but in a preferred embodiment of the invention it is a grained anodized hydrophilic. It is based on aluminum with a textured surface. Although any type of inkjet system is useful with the present invention, FIG. 3 illustrates a comprehensive impulse drop-on-demand system. This is the preferred system of the present invention. As the inkjet head 39 moves over the surface 16, a pattern of dots 44 forming the image to be printed with it is deposited on the surface 16 of the substrate 8. After fluid deposition, the plate 46 is heated by any means known to those skilled in the art to evaporate any water in the fluid and fuse the resin onto the substrate 8. To be done.

FIG. 4 illustrates a plate 46 made according to the method of the present invention described above and shown in FIG. 3 in a cylinder 48 of an offset lithographic press 56 used in combination with a CTP inkjet system 30. Fig. 5 shows a further aspect of the method of the invention, which is mounted. The inkjet marking fluid is deposited in a digitally defined pattern that provides information directly from the computer to the plate.
A sequence of data pulses 42 originating from a computer workstation 20 activates a transducer 45, which controls the flow of inkjet marking fluid provided by the inkjet system 30, thereby causing the marking fluid to flow, It is ejected into a stream of droplets 40 that fall through an inkjet printer nozzle 34 onto the surface of a printing plate 46. The droplet 40 is the inkjet head 3
As 9 moves over the surface of plate 46, it creates a pattern of halftone dots 44, thus forming an image on the surface of plate 46. After the marking fluid is deposited on the printing plate 46, by heating the printing plate 46 with a drying system 62, which can be any drying system known to one of ordinary skill in the art. , Plate 4
All the water remaining on the surface of 6 is evaporated, and the resin is fused to the substrate of the printing plate 46. The plate 46 is then wetted with a fountain solution applied by a wetting cylinder 58, and the imaged area is inked by an inking cylinder 60, which is then rotated by the cylinder press to blanket cylinder 5;
Moved to 0. Thus, the inked image is further transferred to paper 54 as it is pressed between blanket cylinder 50 and impression cylinder 52.

In a further aspect of the invention shown in FIG. 5, the printed image is erasable and the offset lithographic press is a plateless plate. The inkjet system 30 is
The marking fluid 40 is depicted as being jetted onto the surface of an erasable cylinder 48. The erasable cylinder 48 serves as a substrate for direct deposition of the marking fluid droplets 40 and includes any type of hydrophilic surface known to those skilled in the art. In this preferred embodiment, the cylinder 48 comprises a grained anodized aluminum surface. Although any type of inkjet system is useful with the present invention, FIG. 5 illustrates a generic impulse drop-on-demand system 30. This is the preferred system of the present invention. Data pulse sequence 4 for activating transducer 45 using computer 20
Gives rise to 2. The transducer 45 causes the nozzle 3 to create a pattern of dots 44 as the inkjet head 39 moves over the surface of the erasable cylinder 48.
An electrical signal for controlling the ejection of the ink jet marking fluid ejected from the ink jet head 39 into the flow of the droplet 40 via the nozzle 4 is emitted. Thus,
The inkjet marking fluid in the form of droplets 44 is deposited in a digitally defined pattern to provide information directly from a computer workstation 20 to a plateless erasable cylinder 48. After the marking fluid 44 is deposited on the erasable cylinder 48, it is dried by a drying system 62, which can be any heating method known to one of ordinary skill in the art, in the fluid. Water is evaporated and the resin is fused to the substrate. During printing, the fountain solution is applied to the erasable cylinder 48 by the wetting cylinder 58, and the imaged area consisting of the pattern of dots 44 is inked by the inking cylinder 60 and then the lithographic printing machine 56. The rotation of the cylinders causes them to be transferred to the blanket cylinders 50, thus the inked image consists of paper 54 in the example shown, which is pressed between the blanket cylinder 50 receiving the inked image and the impression cylinder 52. Transferred to the printing surface. The dried image may be rubbed or with the aid of an aqueous fluid having either a high or low pH after the printing process, or to decompose any remaining cured image and clean the erasable cylinder 48. It can be erased by either applying a high temperature to (the cylinder is now ready to accept a new image).

In accordance with the principles of the present invention, the inkjet medium is provided in the form of a dispersion. True solutions, whether they are water-based, oil-based, or solvent-based,
It is known to those skilled in the art to provide poorly imaged printing plates due to their tendency to spread over the surface of the plate.

The present invention has overcome this difficulty by utilizing a two-phase fluid containing a combination of resin dispersions in water. Upon contact with the plate, the outer aqueous phase of the inkjet fluid is separated from the inner phase by both capillary action and evaporation onto the hydrophilic plate surface, providing a smooth, clear printed image on the plate. It leaves behind a relatively high viscosity internal phase of the coalescing dispersion.

In a preferred embodiment of the invention, inkjet marking fluids based on an internal dispersed phase and a continuous aqueous dispersion medium are utilized. The particle size of the inner phase is 4 nm to 3 microns. The inkjet marking fluid in this preferred embodiment is characterized by a viscosity of greater than 2 centipoise but less than 40 centipoise, and more specifically a viscosity of 3-25 centipoise. The surface tension of this marking fluid should be in the range of 28-60 dynes / cm. The amount of polymeric binder that constitutes the internal phase of the dispersion should be at least 5% by weight, and in the preferred embodiment should be in the range of 8-20% by weight.

In a preferred embodiment of the invention, the internal phase of the dispersion is a polymer selected from the group:

[0033]     Urethanes     Acrylates     Methacrylates     styrene     Vinyl acetate and other vinyl esters (eg, laurate)     ethylene     butadiene     Vinyl chloride     Vinylidene chloride     Copolymer of the above substances

Other ingredients present in the inkjet fluid are known to those of ordinary skill in the art. These include humectants, dyes, pigments, cosolvents and coalescing agents. The preferred additive in these fluids is a water-soluble low molecular weight polymer which acts as a surfactant in stabilizing the system and at the same time helps maintain the sharpness of the print on the imaged printing plate. It is united. Another preferred type of component is that the dispersed polymer particles ensure that the image coalesces on the surface of the plate and that the water is necessary to form a smooth image after leaving the system. It is an auxiliary agent. Although the system requires some coloring or dyeing material to make the image on the plate visible, the preferred embodiment provides, but is not limited to, mechanical resistance of the image to the printing process. Intrinsically lipophilic carbon black at a concentration of up to 15% by weight for this purpose serves this purpose.

The above rheological properties enable the ink jet marking fluid to produce small droplets (3 picoliters minimum) that provide high resolution. At the same time, the combination of high viscosity and surface tension of the dispersion limits the spreading of the inkjet marking fluid on the high surface energy surface of the hydrophilic printing plate. Thus, the size of the particle dots in the image can be controlled by a suitable combination of the properties of the marking fluid, especially by adjusting the viscosity of the marking fluid.

By introducing various forms of energy, it is possible to further improve the abrasion resistance of the jetted image and increase the run length. This is about 2 images holding plate
This can be done by heating to a temperature of up to 00 ° C. to increase the crosslink density of the polymer. In a preferred embodiment of the invention, the imaged printing plate is 100-14.
Heat to a temperature of 0 ° C. Alternatively, when the composition of the inkjet marking fluid is based on a photosensitive monomer or oligomer with a photoinitiator, drying is performed by exposing the imaged printing plate to UV light.

The ink-jet printing system can, by itself, simply function and operate as a plate-making device, or it can be incorporated directly into a lithographic printing press. In the latter case, printing can be started immediately after the image is applied to a blank printing plate and dried, which considerably reduces the set-up time of the printing press. The inkjet imaging system can be arranged either as a flatbed printing system or as a cylinder printing system in which a lithographic printing plate blank is mounted on the flatbed printing system or attached to the outer surface of a cylindrical surface.

In another aspect of the invention, the inkjet marking fluid is deposited directly onto the erasable cylinder of an offset printing machine which serves as the printing surface in a plateless system.

The following are examples of preferred embodiments of marking fluids used in the printing method of the present invention. In these examples, all parts are given by weight.

Example 1 S. C. 7 parts of acrylic polymer emulsion, 12 parts of ethylene glycol sold by SC Johnson under the trade name of Joncryl 538.
Part, di-propylene glycol-monomethyl ether (DPM) 1 part, a black pigment sold under the trade name of Hostafine Black TS by Clariant GmbH (or Bayscript by BAYER). An ink jet marking fluid was prepared consisting of 1 part magenta dye sold under the trade name Bayscript Magenta) and 12 parts deionized water. Then
A 200 micron thick grained anodized aluminum printing plate was placed on an XY bed where the plate was transferred to European Patent E assigned to Scitex.
An image (600 dpi image) was formed using an inkjet printhead using the above liquid described in P6404041. The plate is then heated to 140 ° C. and heated for 2 minutes, then Heidleberg GT
It was mounted on an O-printing machine where it printed 50,000 good impressions on high quality coated paper.

Example 2 S. C. 7 parts acrylic polymer emulsion, 12 parts ethylene glycol, 1 part DPM, sold by Johnson under the trade name John Cryl 537, and a black pigment sold by Clariant under the trade name Hostafine Black TS (or Bayer by Bay An ink jet marking fluid was prepared consisting of 1 part magenta dye sold under the trade name Script Magenta) and 13 parts deionized water. Imaging, heat treatment and testing were performed as described in Example 1. This process gave results similar to those reported in Example 1.

Example 3 S. C. 7 parts acrylic emulsion, 12 parts ethylene glycol, sold by Johnson under the trade name John Krill 2177, black pigment sold by Clariant under the trade name Hostafine Black TS (or a product by Bayscript Magenta by Buyer). An ink jet marking fluid was prepared consisting of 1 part magenta dye sold under the trade name) and 13 parts deionized water. The imaging, heat treatment and testing described in Example 1 gave results similar to those reported in Example 1.

Example 4 Morton sells 7 parts acrylic emulsion polymer under the trade name Lucidene 366, 12 parts ethylene glycol, Clariant sells under the trade name Hostafine Black TS. An ink jet marking fluid was prepared consisting of 1 part black pigment (or magenta dye sold by Bayer under the trade name Magenta Bayscript) and 14 parts deionized water. The imaging, heat treatment and testing described in Example 1 gave results similar to those of Example 1.

Example 5 8 parts acrylic emulsion polymer sold by Morton, Inc. under the trade name Luciden 388, 12 parts ethylene glycol; a black pigment sold by Clariant under the trade name Hostafine Black TS (or Buyer Inc.). An ink jet marking fluid consisting of 1 part of magenta dye sold under the trade name of Magenta Bayscript) and 13 parts of deionized water was prepared. The imaging, heat treatment and testing described in Example 1 gave results similar to those of Example 1.

Example 6 11 parts styrene / acrylic emulsion polymer sold by Morton under the trade name Luciden 410, 12 parts ethylene glycol, 1 part DPM, black sold under the trade name Hostafine Black TS by Clariant. An inkjet marking fluid was prepared consisting of 1 part pigment (or magenta dye sold by Bayer under the trade name Magenta Bayscript) and 9 parts deionized water. The imaging, heat treatment and testing described in Example 1 gave results similar to those of Example 1.

EXAMPLE 7 7 parts styrene / acrylic emulsion polymer sold by Morton under the trade name Lucidene 5025, 12 parts ethylene glycol, a black pigment sold by Clariant under the trade name Hostafine Black TS (or 1 part of magenta dye sold by the buyer under the trade name of Magenta Bayscript), and deionized water 1
A 3 part ink jet marking fluid was prepared. The imaging, heat treatment and testing described in Example 1 gave results similar to those reported in Example 1.

Example 8 6 parts vinylidene chloride / acrylic copolymer emulsion sold by BF-Goodrich under the trade name Permax 801; 12 parts ethylene glycol; Hostafine from Clariant. An ink jet marking fluid was prepared consisting of 1 part black pigment sold under the trade name Black TS (or magenta dye sold under the trade name Magenta Bayscript by Bayer) and 13 parts deionized water. The image formation, heat treatment and test described in Example 1
Results similar to those of Example 1 were given.

Example 9 10 parts of an aliphatic urethane polymer dispersion sold by BF-Goodrich under the trade name Sancure 776, from a polymer-dispersed solid of a photoinitiator melamine.
． 6 parts, ethylene glycol 12 parts, 1 part black pigment sold by Clariant under the trade name Hostafine Black TS (or magenta dye sold by Bayer under the trade name Bayscript Magenta) and 11 parts deionized water A fluid for inkjet marking was prepared. The imaging, heat treatment and testing described in Example 1 gave results similar to those of Example 1. The printing plate can be cured to provide exceptional wear resistance by cross-linking the polymer system.

Example 10 10 parts aliphatic urethane polymer dispersion sold by BF-Goodrich under the trade name Suncure 850, sold by Biddle Sawyar under the trade name Quantacure ITX. From photo-initiator polymer dispersed solid to 0.6
Part, ethylene glycol 12 parts, Clariant company Hosta Fine Black T
An ink jet marking fluid was prepared consisting of 1 part black pigment sold under the tradename S (or magenta dye sold under the tradename Magenta Bayscript by Bayer) and 11 parts deionized water. The imaging, heat treatment and testing described in Example 1 gave results similar to those of Example 1. The printing plate can be UV cured to provide exceptional wear resistance by cross-linking the polymer system.

Example 11 This example demonstrates the viscosity of an ink jet marking fluid and the commercially available brush-brush-grained and post-anodized uncoated aluminum. This is the most clear proof of the relationship between the size of dots on an offset printing plate.

S. C. An ink jet marking fluid was prepared and imaged consisting of a variable quantity of an acrylic polymer sold by Johnson under the name John Kryl 538 and the other ingredients described in Example 1.

Table I shows the dot diameters (microns) obtained by using the above ink jet marking fluids at various viscosities.

[0053]

[Table 1]

Example 12 This example demonstrates the viscosity of an ink jet marking fluid and a commercially available brush-grained and post-anodized uncoated aluminum offset printing plate. It proves the relationship between the size of halftone dots.

An inkjet marking fluid was prepared consisting of a variable quantity of an aliphatic urethane polymer dispersion sold by BF-Goodrich under the trade name Sancure 850, and the other ingredients described in Example 10, and Image formed.

Table II shows dot diameters (microns) obtained by using the above ink jet marking fluids having various viscosities.

[0057]

[Table 2]

Although the present invention has been described above with reference to certain specific embodiments, further modifications will be apparent to those skilled in the art, and the above description is not intended to limit the present invention. It should be understood that it is intended to cover such modifications as may fall within the scope of the present invention.

[Brief description of drawings]

FIG. 1A shows an enlarged cross-sectional view of a typical multi-layer offset lithographic printing plate known in the art, depicting the process of forming an image using UV light on the plate. .

FIG. 1B shows an enlarged cross-sectional view of a typical multi-layer offset lithographic printing plate known in the art, depicting the process of forming an image using UV light on the plate. .

FIG. 1C shows an enlarged cross-sectional view of a typical multi-layer offset lithographic printing plate known in the art, depicting the process of forming an image using UV light on the plate. .

FIG. 2A is an enlarged cross-sectional view of a typical multi-layer offset lithographic printing plate known in the prior art, showing the process of forming an image using the infrared laser ablation method on the plate. It is drawn.

FIG. 2B shows an enlarged cross-sectional view of a typical multi-layer offset lithographic printing plate known in the prior art, showing the process of forming an image using the infrared laser ablation method on the plate. It is drawn.

FIG. 2C shows an enlarged cross-sectional view of a typical multi-layer offset lithographic printing plate known in the art, in which the process of forming an image using infrared laser ablation It is drawn.

FIG. 3 illustrates a computer-to-plate system featuring droplet deposition of inkjet marking fluid from an inkjet printhead on a printing plate in accordance with the present invention.

FIG. 4 shows a computer-to-plate system, depicting an offset lithographic printing plate made according to the present invention mounted on an offset printing press.

FIG. 5 shows another embodiment of the method of the present invention in which the image to be formed is provided by direct deposition of inkjet marking fluid onto a lithographic printing cylinder in a plateless system.

[Procedure for Amendment] Submission for translation of Article 34 Amendment of Patent Cooperation Treaty

[Submission date] November 18, 2001 (2001.11.18)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Contents of correction]

Title: Fluid for plate making and method of using the fluid

[Claims]

Detailed Description of the Invention     (Field of the invention)

The present invention relates generally to the production of printing plates using the computer-to-plate (CTP) method with inkjet printing, and more particularly to novel inkjet marking fluids and offset lithographic printing. Printing plate (offset litho
Direct CTP creation method for graphic printing plates).

BACKGROUND OF THE INVENTION The offset lithographic printing method is mainly used because a printing plate can be produced relatively easily.
It has been regarded as a popular printing method for many years. At present, the most widely used plate-making method still utilizes a specially manufactured masking film in which a pre-sensitized printing blank is selectively cured or softened by exposure to UV light-according to the chemistry of the plate- Has become a way to do. The plate is then subjected to a development process during which the more soluble areas of the plate are washed away. For a detailed description of a typical system and the plates used, see Bob Thompson (Bob
Thompson) book title "Printing Materials: Science and Technology:
Science and Technology) "(Laser Head, Surrey, UK)
Leatherhead], Pira Int., 1998), Chapter 20.

In recent years, various considerations have emerged that address the benefits of modifying what has heretofore been generally accepted. With the advent of computers, printing information has been digitally processed, and it has therefore become desirable to use this digital information as directly as possible in plate making. One obvious way would be to eliminate the masking film. Not only are these films a source of expense, but the most widely used films are based on silver chemistry, so exposure and handling of the films must be done in a light-excluded environment. In addition, exposed films must be processed with unstable, cumbersome, and environmentally problematic chemical solutions. One answer can be found in computer-to-plate (CTP) systems, which results in offset litho plates.
The graphic plate is imaged directly by a light source that is modulated to correspond to digital information from the computer. Thus, the film intermediate material is omitted altogether. Such printing plates generally still require solution processing, although attempts have been made to develop an unprocessed CTP system. A more detailed description of the subject of the CTP system can be found in the above cited book (Thompson, supra), Chapter 21.

US Pat. No. 5,339,737 to Lewis et al. Describes a method for making unprocessed offset lithographic printing plates in which the upper layer or layers of the plate are removed by ablation. Has been done. The upper layer is a waterless printing plate (wa
It is either oleophobic for terless plates) or hydrophilic for conventional wet process printing plates. The substrate is lipophilic in both cases. Another patent similar to that described above is US Pat. No. 5,353,705 to Lewis et al., Which describes an additional layer for the second partial ablation. Yet another patent that utilizes ablation is US Pat. No. 5,487,338 to Lewis et al., Which patent involves the use of a reflective layer. All of these prior art inventions are expensive,
In addition, it requires a multi-layer printing plate that takes time to create. Further, it is more difficult to maintain a quality standard that does not vary from printing plate to printing plate. Moreover, they utilize inherently expensive laser imaging systems. Due to these disadvantages, the demands of many small to medium sized businesses are not addressed by these prior art inventions.

There is a need for a platemaking process that has the highest degree of simplicity, eliminates any chemical processing, and can be performed at the least cost for platemaking and associated equipment. This method should also be quick.

Inkjet printing is a non-impact digital printing method that allows images to be created and printed under computer control. Inkjet inks are jetted through very fine nozzles and the resulting ink droplets form an image directly on a substrate. These are two important types of inkjet method. In one method, commonly referred to as "continuous inkjet printing", a stream of ink droplets is charged and then either directly or indirectly by an electric field onto a substrate. Biased. The viscosity of the ink used in such systems is typically 2 or 3 centipoise. "Drop-on-
In a second method, commonly referred to as the “drop on demand (DOD) inkjet printing method”, the ink is supplied by the Trident Ultrajet printhead (
It is regulated by an actuator, such as a piezoelectric actuator of the type used in the Trident Ultrajet Printhead). The pressure created during operation forces the droplet through the nozzle and onto the substrate. The inks for the DOD inkjet printing method need not be conductive and their viscosities are typically 2-40 centipoise.

The prior art has shown some applications of the inkjet printing principle to the production of offset lithographic printing plates.

[0008] In US Pat. No. 4,833,486 to Zerillo, a hydrophobic solid inkjet ink--a phase change inking medium.
Also referred to as change inking medium) -contains a wax that is held at a temperature high enough to eject the ink through a DOD head. This solid phase change ink technology is described in US Pat. No. 4,390,390 to Merritt et al.
369 and 4,484,948 and U.S. Pat. No. 4,593,292 to Lewis. The substrate is
A hydrophilic offset printing plate-either paper or aluminum-on which ink is jetted to form an image. When the ink hits the plate, it immediately cools and solidifies. One problematic and significant drawback of such methods is that it is difficult to obtain a sufficiently high antiplate adhesion of the wax in the ink medium for multiple printing during lithographic printing. is there.

European Patent EP 503 owned by Nippon Paint Co.
No. 621 describes two methods. One method describes jetting ink onto a pre-sensitized printing plate, which plate then requires further processing, including a development step with a liquid developer. Another method uses a non-presensitized printing plate, the inkjet ink of which is photosensitive so that it can be cured on the plate.

European Patent EP 533168, owned by Nippon Paint Co., Ltd., describes the use of a photopolymerizable ink jet ink with an ink-absorbing layer on a lithographic printing plate surface.

[0011] European Patent EP 6972282 to Leanders, owned by Agfa, is a lipophilic reduction which allows the ink to be used in an offset printing process when it hits the plate. A two-component system is described in which one reactive component is present in the ink and the other component is present in the lithographic plate surface so as to produce a silver image.

[0012] Gerber Scientific Products (Gerber Scientific Produc
US Patent No. 5,495,80 to Gerber owned by ts, Inc)
No. 3, a coated presensitized printing plate is imaged with a UV opaque hot melt inkjet ink, which ink is used as a photomask to expose the plate. The non-exposed pre-photopolymer and the ink are subsequently removed by washing.

US Pat. No. 5,738,013 to Kellet includes the use of a reactive inkjet ink that is bound to a lithographic printing plate in a chemical reaction that is activated by radiant energy. It describes how to make a printing plate. This assumes that such inks have very good stability at room temperature, so that ink that does not pass through the inkjet nozzles is blocked.
Moreover, it is envisaged that the ink will have good reactivity at high temperatures so that it becomes insoluble with good offset plate adhesion and good lipophilicity.

International Patent Publication No. WO 9743122 to Kelet has a hydrophilic receptive surface with an ink jet fluid marking material comprising a liquid carrier medium and at least one transition metal complex reactive component or organic reactive component. Media-ink jet fluid ma
rking material set). This fluid is a clear solution in which all components are water soluble and the reactive components undergo chemical reactions. The Kellet patent provides low resolution because the viscosity and thus the droplet size is not controllable.

European Patent EP 0 571 190 to Sano et al. Describes pigments;
Disclosed is an inkjet printing ink containing a component selected from the group consisting of a polysaccharide, a derivative thereof and a polyol having 5 or 6 or more hydroxyl groups; and a resin emulsion. This is a non-aqueous printing ink, not an aqueous fluid for making a printing plate.

European Patent EP 0 808 882 to Spinelli is
It uses a two-phase dispersion that allows the solution to be used for bleed by placing the pigment in one phase.

European Patent EP 0 922 737 to Parazak is
The present invention provides a pigment-based ink composition using a pigment precursor that is soluble in a non-aqueous solvent. The ink composition is preferably in the form of an aqueous two-phase system in which the pigment precursor is solubilized in a high boiling water-insoluble organic compound. The use of two phases is due to the pigment.

Thus, while there have been prior art attempts to use the inkjet method for direct imaging of printing plates, they seek to provide satisfactory quality and run length while maintaining reasonable cost and run time. If that is still difficult. Both water-based and solvent-based inks have the problem of spreading on a hydrophilic printing plate with high surface energy due to the properties required to eject the ink. Phase change inks have the problem that wax-like inks bond to the plate. In addition, there is a need to eliminate further liquid processing and to provide a simple platemaking process, i.e., to eliminate printing plate components and form an image directly on the printing surface of a lithographic press.

SUMMARY OF THE INVENTION Accordingly, a primary object of the present invention is to provide a simple and inexpensive method of making offset lithographic printing plates by use of the inkjet method, thereby providing a computer-to-computer method of the prior art. Overcoming the disadvantages associated with the plate method. This method uses a novel inkjet fluid that can be easily dried on an uncoated lithographic printing plate while providing excellent jettability with a high degree of consistency and quality. .

[0020]   According to one preferred method of the present invention, a direct CTP preparation method of a printing plate comprising:

Providing a digital image made by a computer system; providing an inkjet marking fluid having a preselected viscosity,
Where the marking fluid comprises a two-phase dispersion system consisting of a lipophilic internal phase containing any combination of resin dispersions in water and a continuous aqueous dispersion medium;

[0022]   Jetting the marking fluid onto the printing surface; and   Dry the marking fluid on the printed surface A method as described above is provided that comprises steps.

In this preferred method, the inkjet marking fluid is deposited in a pattern that is digitally defined to provide information directly from the computer to the printing plate. According to the method of the present invention, the dot size of the inkjet fluid deposited on the printing surface of an offset printing press is controlled by adjusting the viscosity of the fluid, thus relating to the quality of the image to be printed. Good control is achieved.

In another preferred method, the novel inkjet marking fluids of the present invention can be used directly in plateless lithographic printing systems to print large quantities of good quality impressions. Form a strong, stable lipophilic image.

Other features and advantages of the invention will be apparent from the more detailed description and examples.

For the purpose of better understanding the invention with respect to aspects of the invention, the accompanying drawings (
(No scale). In the accompanying drawings, like numbers indicate corresponding elements or parts throughout.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIGS. 1A, 1B and 1C, which illustrate steps in a widely used prior art method of making a plate using a pre-sensitized printing plate. 1
An example is shown.

FIG. 1A shows a film 2 containing the image 4 to be printed in negative form. The pre-sensitized printing plate 6 comprises a grained anodized aluminum substrate 8 and is coated with a photosensitive polymer layer 10 comprising a photosensitive prepolymer and a carrier resin. The film 2 is placed in emulsion-to-emulsion contact with the presensitized printing plate 6 and is flood illuminated with ultraviolet light 12 as shown in FIG. 1B. The transparent area 4 of the negative film 2 represents the image area to be printed, U
V light 12 reacts to form a hard insoluble lipophilic region 14 photopolymer layer 1
Allows transmission to zero. The black areas 5 of the negative film 2 correspond to the background areas of the print and prevent the UV light 12 from passing therethrough and thus the photosensitive layer 10
Those parts of remain in the prepolymer state. The negative film 2 is then removed, and the printing plate 6--usually with an aqueous solution of high pH in which the unpolymerized parts of the layer 10 are easily dissolved--is processed. This exposes the grained anodized surface 16 of the substrate 8 and its processed hydrophilic background region is now ready for mounting in a conventional offset lithographic press, as shown in FIG. 1C. It can be used for printing plates.

2A, 2B and 2C are enlarged views of the steps of the simplified, infrared ablatable computer-to-plate method known in the prior art. FIG. 2A depicts an unprocessed printing plate 26 including a substrate 8 which may be, for example, aluminum; an infrared absorbing layer 22; and a hydrophilic top coating 24. In FIG. 2B, plate 26 is imaged with digitally modulated infrared radiation 28 absorbed by layer 22. The absorbed energy causes a very fast temperature rise, resulting in ablation of layer 22. This ablation removes portions of hydrophilic coating 22 as well as layer 22.
FIG. 2C shows the obtained printing plate, which is a part of the coating 24 that becomes the hydrophilic background region of the printing plate 26 and the surface 16 of the substrate 8 that becomes the lipophilic image forming part of the printing plate 26. With exposed parts of.

Referring now to FIG. 3, there is shown a computer-to-plate inkjet printing system 3 constructed and operated in accordance with the principles of the present invention.
0 is shown. Computer 20 is used to generate a data pulse sequence 42 which energizes transducer 45. The transducer 45 emits an electrical signal that activates the piezoelectric crystal 36. The crystals 36 create a pressure wave inside the ink chamber 38, which causes the ink jet fluid 32 in the ink chamber 38 to drop through the ink jet printer nozzle 34 onto the surface 16 of a typical plate substrate 8. Inject into the flow of. The substrate 8 can be any type of substrate known to those skilled in the art in which offset lithographic printing plates are processed, but in a preferred embodiment of the invention it is a grained anodized hydrophilic. It is based on aluminum with a textured surface. Although any type of inkjet system is useful with the present invention, FIG. 3 illustrates a comprehensive impulse drop-on-demand system. This is the preferred system of the present invention. As the inkjet head 39 moves over the surface 16, a pattern of dots 44 forming the image to be printed with it is deposited on the surface 16 of the substrate 8. After fluid deposition, plate 46 is heated by any means known to those skilled in the art to evaporate any water in the fluid and fuse the resin onto substrate 8. To be done.

FIG. 4 illustrates a plate 46 made according to the method of the present invention described above and shown in FIG. 3 in a cylinder 48 of an offset lithographic press 56 used in combination with a CTP inkjet system 30. Fig. 5 shows a further aspect of the method of the invention, which is mounted. The inkjet marking fluid is deposited in a digitally defined pattern that provides information directly from the computer to the plate.
A sequence of data pulses 42 originating from a computer workstation 20 activates a transducer 45, which controls the flow of inkjet marking fluid provided by the inkjet system 30, thereby causing the marking fluid to flow, It is ejected into a stream of droplets 40 that fall through an inkjet printer nozzle 34 onto the surface of a printing plate 46. The droplet 40 is the inkjet head 3
As 9 moves over the surface of plate 46, it creates a pattern of halftone dots 44, thus forming an image on the surface of plate 46. After the marking fluid is deposited on the printing plate 46, by heating the printing plate 46 with a drying system 62, which can be any drying system known to one of ordinary skill in the art. , Plate 4
All the water remaining on the surface of 6 is evaporated, and the resin is fused to the substrate of the printing plate 46. The plate 46 is then wetted with a fountain solution applied by a wetting cylinder 58, and the imaged area is inked by an inking cylinder 60, which is then rotated by the cylinder press to blanket cylinder 5;
Moved to 0. Thus, the inked image is further transferred to paper 54 as it is pressed between blanket cylinder 50 and impression cylinder 52.

In a further aspect of the invention shown in FIG. 5, the printed image is erasable and the offset lithographic press is a plateless plate. The inkjet system 30 is
The marking fluid 40 is depicted as being jetted onto the surface of an erasable cylinder 48. The erasable cylinder 48 serves as a substrate for direct deposition of the marking fluid droplets 40 and includes any type of hydrophilic surface known to those skilled in the art. In this preferred embodiment, the cylinder 48 comprises a grained anodized aluminum surface. Although any type of inkjet system is useful with the present invention, FIG. 5 illustrates a generic impulse drop-on-demand system 30. This is the preferred system of the present invention. Data pulse sequence 4 for activating transducer 45 using computer 20
Gives rise to 2. The transducer 45 causes the nozzle 3 to create a pattern of dots 44 as the inkjet head 39 moves over the surface of the erasable cylinder 48.
An electrical signal for controlling the ejection of the ink jet marking fluid ejected from the ink jet head 39 into the flow of the droplet 40 via the nozzle 4 is emitted. Thus,
The inkjet marking fluid in the form of droplets 44 is deposited in a digitally defined pattern to provide information directly from a computer workstation 20 to a plateless erasable cylinder 48. After the marking fluid 44 is deposited on the erasable cylinder 48, it is dried in a drying system 62, which can be any heating method known to one of ordinary skill in the art. Water is evaporated and the resin is fused to the substrate. During printing, the fountain solution is applied to the erasable cylinder 48 by the wetting cylinder 58, and the imaged area consisting of the pattern of dots 44 is inked by the inking cylinder 60, and then the lithographic printing machine 56. The rotation of the cylinders causes them to be transferred to a blanket cylinder 50, thus the inked image is composed of paper 54 in the example shown, which is pressed between the blanket cylinder 50 receiving the inked image and the impression cylinder 52. Transferred to the printing surface. The dried image may be rubbed or with the aid of an aqueous fluid having either a high or low pH after the printing process, or to decompose any remaining cured image and clean the erasable cylinder 48. It can be erased by either applying a high temperature to (the cylinder is now ready to accept a new image).

In accordance with the principles of the present invention, the inkjet medium is provided in the form of a dispersion. True solutions, whether they are water-based, oil-based, or solvent-based,
It is known to those skilled in the art to provide poorly imaged printing plates due to their tendency to spread over the surface of the plate.

The present invention has overcome this difficulty by utilizing a two-phase fluid containing a combination of resin dispersions in water. Upon contact with the plate, the outer aqueous phase of the inkjet fluid is separated from the inner phase by both capillary action and evaporation onto the hydrophilic plate surface, providing a smooth, clear printed image on the plate. It leaves behind a relatively high viscosity internal phase of the coalescing dispersion.

A preferred embodiment of the present invention utilizes an inkjet marking fluid based on an internal dispersed phase and a continuous aqueous dispersion medium. The particle size of the inner phase is 4 nm to 3 microns. The inkjet marking fluid in this preferred embodiment is characterized by a viscosity of greater than 2 centipoise but less than 40 centipoise, and more specifically a viscosity of 3-25 centipoise. The surface tension of this marking fluid should be in the range of 28-60 dynes / cm. The amount of polymeric binder that constitutes the internal phase of the dispersion should be at least 5% by weight, and in the preferred embodiment should be in the range of 8-20% by weight.

In a preferred embodiment of the invention, the internal phase of the dispersion is a polymer selected from the following group:

[0037]     Urethanes     Acrylates     Methacrylates     styrene     Vinyl acetate and other vinyl esters (eg, laurate)     ethylene     butadiene     Vinyl chloride     Vinylidene chloride     Copolymer of the above substances

Other components present in the inkjet fluid are known to those of ordinary skill in the art. These include humectants, dyes, pigments, cosolvents and coalescing agents. The preferred additive in these fluids is a water-soluble low molecular weight polymer which acts as a surfactant in stabilizing the system and at the same time helps maintain the sharpness of the print on the imaged printing plate. It is united. Another preferred type of component is that the dispersed polymer particles ensure that the image coalesces on the surface of the plate and that the water is necessary to form a smooth image after leaving the system. It is an auxiliary agent. Although the system requires some coloring or dyeing material to make the image on the plate visible, the preferred embodiment provides, but is not limited to, mechanical resistance of the image to the printing process. Intrinsically lipophilic carbon black at a concentration of up to 15% by weight for this purpose serves this purpose.

The above rheological properties enable the inkjet marking fluid to produce small droplets (3 picoliters minimum) that provide high resolution. At the same time, the combination of high viscosity and surface tension of the dispersion limits the spreading of the inkjet marking fluid on the high surface energy surface of the hydrophilic printing plate. Thus, the size of the particle dots in the image can be controlled by a suitable combination of the properties of the marking fluid, especially by adjusting the viscosity of the marking fluid.

By introducing various forms of energy, it is possible to further improve the abrasion resistance of the jetted image and increase the run length. This is about 2 images holding plate
This can be done by heating to a temperature of up to 00 ° C. to increase the crosslink density of the polymer. In a preferred embodiment of the invention, the imaged printing plate is 100-14.
Heat to a temperature of 0 ° C. Alternatively, when the composition of the inkjet marking fluid is based on a photosensitive monomer or oligomer with a photoinitiator, drying is performed by exposing the imaged printing plate to UV light.

The ink-jet printing system can, by itself, simply function and operate as a plate-making device, or it can be integrated directly into a lithographic printing press. In the latter case, printing can be started immediately after the image is applied to a blank printing plate and dried, which considerably reduces the set-up time of the printing press. The inkjet imaging system can be arranged either as a flatbed printing system or as a cylinder printing system in which a lithographic printing plate blank is mounted on the flatbed printing system or attached to the outer surface of a cylindrical surface.

In another aspect of the invention, the inkjet marking fluid is deposited directly on the erasable cylinder of an offset printing machine which serves as the printing surface in a plateless system.

The following are examples of preferred embodiments of marking fluids used in the printing method of the present invention. In these examples, all parts are given by weight. In the examples below, the term "emulsion" is used by the manufacturer, but the term "emulsion" is a strict term as the formulations described are chemically dispersions and not emulsions. It is not used as a chemical language.

Example 1 S. C. 7 parts of acrylic polymer emulsion, 12 parts of ethylene glycol sold by SC Johnson under the trade name of Joncryl 538.
Part, di-propylene glycol-monomethyl ether (DPM) 1 part, a black pigment sold under the trade name of Hostafine Black TS by Clariant GmbH (or Bayscript by BAYER). An ink jet marking fluid was prepared consisting of 1 part magenta dye sold under the trade name Bayscript Magenta) and 12 parts deionized water. Then
A 200 micron thick grained anodized aluminum printing plate was placed on an XY bed where the plate was transferred to European Patent E assigned to Scitex.
An image (600 dpi image) was formed using an inkjet printhead using the above liquid described in P6404041. The plate is then heated to 140 ° C. and heated for 2 minutes, then Heidleberg GT
It was mounted on an O-printing machine where it printed 50,000 good impressions on high quality coated paper.

Example 2 S. C. 7 parts acrylic polymer emulsion, 12 parts ethylene glycol, 1 part DPM, sold by Johnson under the trade name John Cryl 537, and a black pigment sold by Clariant under the trade name Hostafine Black TS (or Bayer by Bay An ink jet marking fluid was prepared consisting of 1 part magenta dye sold under the trade name Script Magenta) and 13 parts deionized water. Imaging, heat treatment and testing were performed as described in Example 1. This process gave results similar to those reported in Example 1.

Example 3 S. C. 7 parts acrylic emulsion, 12 parts ethylene glycol, sold by Johnson under the trade name John Krill 2177, black pigment sold by Clariant under the trade name Hostafine Black TS (or a product by Bayscript Magenta by Buyer). An ink jet marking fluid was prepared consisting of 1 part magenta dye sold under the trade name) and 13 parts deionized water. The imaging, heat treatment and testing described in Example 1 gave results similar to those reported in Example 1.

Example 4 Morton sells 7 parts acrylic emulsion polymer under the trade name Lucidene 366, 12 parts ethylene glycol, Clariant sells under the trade name Hostafine Black TS. An ink jet marking fluid was prepared consisting of 1 part black pigment (or magenta dye sold by Bayer under the trade name Magenta Bayscript) and 14 parts deionized water. The imaging, heat treatment and testing described in Example 1 gave results similar to those of Example 1.

Example 5 Morton Co. sells 8 parts of acrylic emulsion polymer sold under the trade name of Luciden 388, 12 parts of ethylene glycol, Clariant sells black pigment sold under the trade name of Hostafine Black TS (or Buyer Co.). An ink jet marking fluid consisting of 1 part of magenta dye sold under the trade name of Magenta Bayscript) and 13 parts of deionized water was prepared. The imaging, heat treatment and testing described in Example 1 gave results similar to those of Example 1.

Example 6 11 parts styrene / acrylic emulsion polymer sold by Morton, Inc. under the trade name Luciden 410, 12 parts ethylene glycol, 1 part DPM, black sold under the trade name Hostafine Black TS by Clariant. An inkjet marking fluid was prepared consisting of 1 part pigment (or magenta dye sold by Bayer under the trade name Magenta Bayscript) and 9 parts deionized water. The imaging, heat treatment and testing described in Example 1 gave results similar to those of Example 1.

Example 7 7 parts styrene / acrylic emulsion polymer sold by Morton under the trade name Lucidene 5025, 12 parts ethylene glycol, a black pigment sold by Clariant under the trade name Hostafine Black TS (or 1 part of magenta dye sold by the buyer under the trade name of Magenta Bayscript), and deionized water 1
A 3 part ink jet marking fluid was prepared. The imaging, heat treatment and testing described in Example 1 gave results similar to those reported in Example 1.

Example 8 6 parts vinylidene chloride / acrylic copolymer emulsion sold by BF-Goodrich under the trade name of Permax 801 6 parts ethylene glycol, Clariant company Hostafine An ink jet marking fluid was prepared consisting of 1 part black pigment sold under the trade name Black TS (or magenta dye sold under the trade name Magenta Bayscript by Bayer) and 13 parts deionized water. The image formation, heat treatment and test described in Example 1
Results similar to those of Example 1 were given.

Example 9 10 parts of an aliphatic urethane polymer dispersion sold by BF-Goodrich under the trade name Sancure 776, from a polymer-dispersed solid of a photoinitiator melamine.
． 6 parts, ethylene glycol 12 parts, 1 part black pigment sold by Clariant under the trade name Hostafine Black TS (or magenta dye sold by Bayer under the trade name Bayscript Magenta) and 11 parts deionized water A fluid for inkjet marking was prepared. The imaging, heat treatment and testing described in Example 1 gave results similar to those of Example 1. The printing plate can be cured to provide exceptional wear resistance by cross-linking the polymer system.

Example 10 10 parts aliphatic urethane polymer dispersion sold by BF-Goodrich under the trade name Suncure 850, sold by Biddle Sawyar under the trade name Quantacure ITX. From photo-initiator polymer dispersed solid to 0.6
Part, ethylene glycol 12 parts, Clariant company Hosta Fine Black T
An ink jet marking fluid was prepared consisting of 1 part black pigment sold under the tradename S (or magenta dye sold under the tradename Magenta Bayscript by Bayer) and 11 parts deionized water. The imaging, heat treatment and testing described in Example 1 gave results similar to those of Example 1. The printing plate can be UV cured to provide exceptional wear resistance by cross-linking the polymer system.

Example 11 This example demonstrates the viscosity of an ink jet marking fluid and the commercially available brush-brush-grained and post-anodized uncoated aluminum. This is the most clear proof of the relationship between the size of dots on an offset printing plate.

S. C. An ink jet marking fluid was prepared and imaged consisting of a variable quantity of an acrylic polymer sold by Johnson under the name John Kryl 538 and the other ingredients described in Example 1.

Table I shows the dot diameters (microns) obtained using the ink jet marking fluids at various viscosities.

[0057]

[Table 1]

Example 12 This example demonstrates the viscosity of an ink jet marking fluid and a commercially available brush-grained and post-anodized uncoated aluminum offset printing plate. It proves the relationship between the size of halftone dots.

An ink jet marking fluid was prepared consisting of a variable quantity of an aliphatic urethane polymerized dispersion sold by BF-Goodrich under the trade name Sancure 850, and the other ingredients described in Example 10, and Image formed.

Table II shows dot diameters (microns) obtained by using the above ink jet marking fluids having various viscosities.

[0061]

[Table 2]

Although the present invention has been described above with reference to certain specific embodiments, further modifications will be apparent to those skilled in the art, and the above description is not intended to limit the present invention. It should be understood that it is intended to cover such modifications as may fall within the scope of the present invention.

[Brief description of drawings]

FIG. 1A shows an enlarged cross-sectional view of a typical multi-layer offset lithographic printing plate known in the art, depicting the process of forming an image using UV light on the plate. .

FIG. 1B shows an enlarged cross-sectional view of a typical multi-layer offset lithographic printing plate known in the art, depicting the process of forming an image using UV light on the plate. .

FIG. 1C shows an enlarged cross-sectional view of a typical multi-layer offset lithographic printing plate known in the art, depicting the process of forming an image using UV light on the plate. .

FIG. 2A is an enlarged cross-sectional view of a typical multi-layer offset lithographic printing plate known in the prior art, showing the process of forming an image using the infrared laser ablation method on the plate. It is drawn.

FIG. 2B shows an enlarged cross-sectional view of a typical multi-layer offset lithographic printing plate known in the prior art, showing the process of forming an image using the infrared laser ablation method on the plate. It is drawn.

FIG. 2C shows an enlarged cross-sectional view of a typical multi-layer offset lithographic printing plate known in the art, in which the process of forming an image using infrared laser ablation It is drawn.

FIG. 3 illustrates a computer-to-plate system featuring droplet deposition of inkjet marking fluid from an inkjet printhead on a printing plate in accordance with the present invention.

FIG. 4 shows a computer-to-plate system, depicting an offset lithographic printing plate made according to the present invention mounted on an offset printing press.

FIG. 5 shows another embodiment of the method of the present invention in which the image to be formed is provided by direct deposition of inkjet marking fluid onto a lithographic printing cylinder in a plateless system.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), OA (BF , BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, G M, KE, LS, MW, MZ, SD, SL, SZ, TZ , UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, B Z, CA, CH, CN, CR, CU, CZ, DE, DK , DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, J P, KE, KG, KP, KR, KZ, LC, LK, LR , LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, R O, RU, SD, SE, SG, SI, SK, SL, TJ , TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Kimel Bratt, Junkieru             Hatavos, Rana, Israel             Treat 3 F-term (reference) 2C056 EA24 FB01                 2H084 AA25 AE05 BB02 BB13 CC05                 4J039 AD01 AD03 AD05 AD08 AD10                       AD21 AE04 BA04 BC09 BC13                       BE01 BE02 CA06 EA06 GA02                       GA24

Claims (41)

[Claims] 1. A method for direct CTP production of a printing plate, comprising preparing a digital image produced by a computer system; preparing a fluid for inkjet marking having a viscosity selected in advance,
Wherein the inkjet marking fluid comprises a two-phase emulsion system consisting of a lipophilic internal phase and a continuous aqueous dispersion medium; the marking fluid is jetted onto the printing surface using an inkjet printing device;
And a method as described above, comprising drying the marking fluid on the printing surface. 2. The method of claim 1, wherein the internal phase of the marking fluid comprises any combination of resin dispersions in water. 3. The method of claim 1, wherein the internal phase of the marking fluid comprises a binder having 8-20% by weight of the liquid medium in the marking fluid. 4. The method of claim 1, wherein the marking fluid has an internal phase characterized by a particle size of 4 nm to 3 microns. 5. The marking fluid has a viscosity of 2-40 centipoise.
The method of claim 1. 6. The method of claim 1, wherein the marking fluid has a surface tension in the range of 28-60 dynes / cm. 7. The dispersion comprises urethanes, acrylates, methacrylates,
A process according to claim 2 comprising a polymer selected from the group comprising styrene, ethylene, butadiene, vinyl chloride, vinylidene chloride, vinyl acetate and other vinyl esters, copolymers of these substances and mixtures thereof. 8. The dispersion comprises a photosensitive monomer in combination with a photoinitiator, wherein the marking fluid is cured on the printing plate when exposed to UV light.
The method described. 9. The method of claim 2, wherein the dispersion comprises a photo-sensitive oligomer in combination with a photoinitiator, wherein the marking fluid is cured on the printing plate when exposed to UV light. 10. The method of claim 2, wherein the marking fluid further comprises humectants, dyes, pigments, cosolvents and coalescing agents. 11. The method of claim 10, wherein the humectant is selected from the group comprising glycols, glycol ethers, glycol ether acetates, N-methylpyrrolidone and substituted pyrrolidones. 12. The method according to claim 10, wherein the dye comprises less than 15% by weight concentration of carbon black. 13. The method of claim 10, wherein the pigment comprises less than 15 wt% concentration of carbon black. 14. The method of claim 10, wherein the coalescing agent is selected from the group comprising glycol ethers, glycol acetates and butyl carbitol. 15. The method of claim 1, wherein the printing surface is hydrophilic. 16. The method of claim 1, wherein the printing surface comprises a polyester printing plate. 17. The method of claim 16, wherein the polyester printing plate comprises a grained anodized aluminum substrate. 18. The method of claim 16 further comprising the step of incorporating the printing plate into an offset lithographic printing press system. 19. The printing press system includes a lithographic printing platen system.
8. The method according to 8. 20. The method of claim 18, wherein the printing press system comprises an offset lithographic cylinder-press system. 21. The drying step is accomplished by exposure to UV light,
The method of claim 1. 22. The method of claim 1, wherein the drying step is accomplished by thermal processing.
The method described. 23. The method of claim 22, wherein the thermal processing is accomplished by raising and heating the printing surface to a temperature of 100-140 ° C. 24. The method of claim 1, wherein the inkjet printing device comprises a drop-on-demand system. 25. The method of claim 1, wherein the inkjet printing device comprises a continuous system. 26. The method of claim 1, wherein the printing surface comprises a plateless lithographic press cylinder. 27. The method of claim 1, wherein the printing surface comprises a plateless lithographic printing press. 28. An ink jet marking fluid for use in a direct CTP making method of a printing plate comprising a two phase emulsion system having a lipophilic internal phase and a continuous aqueous dispersion medium. 29. The marking fluid of claim 28, wherein the internal phase comprises any combination of resin dispersions in water. 30. The marking fluid according to claim 28, wherein the internal phase comprises a binder having 8-20% by weight of the liquid medium in the marking fluid. 31. The internal phase is characterized by a particle size of 4 nm to 3 microns.
8. The marking fluid according to item 8. 32. The marking fluid of claim 28, having a viscosity of 2-40 centipoise. 33. The marking fluid according to claim 28, having a surface tension in the range of 28-60 dynes / cm. 34. The dispersion comprises urethanes, acrylates, methacrylates, styrene, ethylene, butadiene, vinyl chloride, vinylidene chloride, vinyl acetate and other vinyl esters, copolymers of these substances and mixtures thereof. 30. The marking fluid according to claim 29, which comprises a polymer selected from the group consisting of: 35. The dispersion comprises a photosensitive monomer in combination with a photoinitiator,
30. The marking fluid of claim 29, wherein the marking fluid is cured on the printing plate when exposed to UV light. 36. The marking fluid according to claim 29, wherein the dispersion comprises a photosensitive oligomer in combination with a photoinitiator, wherein the marking fluid is cured on the printing plate when exposed to UV light. . 37. The marking fluid of claim 29, further comprising humectants, dyes, pigments, cosolvents and coalescing agents. 38. The marking fluid of claim 37, wherein the humectant is selected from the group comprising glycols, glycol ethers, glycol ether acetates, N-methylpyrrolidone and substituted pyrrolidones. 39. The marking fluid of claim 37, wherein the dye comprises less than 15% by weight concentration of carbon black. 40. The marking fluid of claim 37, wherein the pigment comprises less than 15 wt% concentration of carbon black. 41. The marking fluid of claim 37, wherein the coalescing agent is selected from the group comprising glycol ethers, glycol acetates and butyl carbitol.