JP2001175006A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method applicable to a negative image forming material capable of directly recording from digital data using infrared laser, unnecessary for a large-sized device or energy and capable of providing a planographic printing plate excellent in image forming property and printing durability. SOLUTION: An exposure process for image-exposing the negative image forming material provided with a photosensitive layer containing an infrared adsorbent A, a radical generating agent B, a radically polymerizable compound and a binder polymer D on a supporting body, a heating process for heating the exposed image forming material at 60-120 deg.C for 1-20 sec and a developing process for developing the heated image forming material with an alkali aqueous solution are included. The development is preferably performed with the weak alkaline aqueous solution having pH 7-12 and the image forming material preferably has a water soluble over coat layer formed on the photosensitive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method which can be applied to a so-called direct plate making negative type image forming material which can make a plate directly by scanning an infrared laser based on a digital signal from a computer or the like.

[0002]

2. Description of the Related Art Heretofore, as a system for directly making a plate from digital data of a computer, an electrophotographic system, a photopolymerization system for exposing with a laser emitting blue or green light, and a silver salt on a photosensitive resin are known. Laminated ones, silver salt diffusion transfer methods, and the like have been proposed.

However, in the case of using the electrophotographic method, the processes of image formation such as charging, exposure, and development are complicated, and the apparatus is complicated and large. In the case of the photopolymerization system, since a plate material having high sensitivity to blue or green light is used, handling in a bright room becomes difficult. The methods (1) and (2) have drawbacks in that processing such as development becomes complicated because silver salts are used, and silver is contained in the processing waste liquid.

On the other hand, the development of lasers in recent years has been remarkable, and in particular, solid-state lasers and semiconductor lasers that emit infrared light having a wavelength of 760 nm to 1200 nm have become easily available with high output and small size. These lasers are very useful as a recording light source when making a plate directly from digital data of a computer or the like. However, many photosensitive recording materials that are practically useful have a photosensitive wavelength in the visible light range of 760 nm or less, and therefore cannot record images with these infrared lasers. Therefore, a material that can be recorded by an infrared laser is desired.

As an image recording material recordable by such an infrared laser, there is a recording material comprising an onium salt, a phenol resin and a spectral sensitizer described in US Pat. No. 4,708,925. This image recording material is a positive type image recording material utilizing the effect of suppressing dissolution in a developer, which is exhibited by an onium salt and a phenol resin, and is not a negative type as in the present invention. On the other hand, as a negative type image recording material, a recording material comprising an infrared absorber, an acid generator, a resol resin and a novolak resin is disclosed in US Pat.
0,699. However, such a negative type image recording material requires a heat treatment of heating at 140 to 200 ° C. for about 50 to 120 seconds after laser exposure in order to form an image. It required extensive equipment and energy.
For example, JP-A-8-108621 discloses a negative-type image forming material using a photopolymerizable composition. Here, in order to promote thermal polymerization of a recording layer, heating is performed simultaneously with image exposure. There is a statement to the effect. Simultaneous heating in the exposure process has problems such as heating giving thermal fluctuations to the nearby air, blurring the laser focus, affecting image forming properties, and shortening the life of the laser element due to heat. Is not preferred.

Japanese Patent Publication No. 7-103171 discloses a heat treatment after imagewise exposure comprising a cyanine dye having a specific structure, an iodonium salt and an addition-polymerizable compound having an ethylenically unsaturated double bond. Although a recording material that is not required is described, this image recording material has a problem that polymerization is inhibited by oxygen in the air during a polymerization reaction, resulting in a decrease in sensitivity and an insufficient strength of a formed image portion. was there.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a negative type image forming material which can be directly recorded from digital data of a computer or the like by recording using a solid-state laser or a semiconductor laser emitting infrared rays. An object of the present invention is to provide an image forming method capable of obtaining a lithographic printing plate which is applicable and does not require a large-scale apparatus or energy, and has excellent image forming properties and printing durability.

[0008]

Means for Solving the Problems The present inventor paid attention to the physical properties of a negative-type image forming material, and as a result of intensive studies, after forming an image, a mild heat treatment was carried out for a short time prior to development before the above problem. Was found to be able to be solved, and the present invention was completed. That is, according to the image forming method of the present invention, a photosensitive layer containing (A) an infrared absorber, (B) a radical generator, (C) a radical polymerizable compound, and (D) a binder polymer is formed on a support. An exposure step of exposing the negative image forming material provided to an image with an infrared laser, and subjecting the exposed negative image forming material to a temperature of 60 to 120 ° C. for 1 hour.
A heating step of heating for up to 20 seconds, and a developing step of developing the heated negative-type image forming material with an aqueous alkaline solution.

Here, in the developing step, the pH is 7 to 1
It is preferable to develop using a weak alkaline aqueous solution in the range of 2. Further, in order to prevent polymerization inhibition by oxygen, it is preferable to provide a water-soluble overcoat layer on the photosensitive layer in the negative-type image forming material.
It is a preferred embodiment to include a washing step of removing the water-soluble overcoat layer by washing before the developing step. The heating condition in the heating step, which is a characteristic step of the present invention, is preferably controlled by plate information of a negative image forming material on which an image is formed.

Although the operation of the present invention is not clear, heating for a short period of time under mild conditions before development may cause undesired curing of the non-exposed area due to undesired curing of the non-exposed area as in heating by high energy. It is considered that by applying a small amount of energy, only the curing of the exposed portion of the photosensitive layer is accelerated, and clear on / off can be performed to form a good image, and the printing durability is also improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The image forming method of the present invention will be described below in detail according to the steps. Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. In the present embodiment, as shown in FIG. 1, the method of the present invention is applied to a plate making system including a personal computer 10, a work station 12, a plate setter (exposure device) 14, and an image forming material processor (automatic developing device) 16. The case where is applied will be described.

Further, a negative type image forming material used in the present embodiment (hereinafter, also simply referred to as an image forming material as appropriate).
As an example, an aluminum support having a back coat layer on the back surface, an organic undercoat layer, a photopolymerizable photosensitive layer, and an overcoat layer may be provided in this order. The details of the image forming material will be described later.

The plate making system according to the present embodiment includes a personal computer 10, a work station 12, a plate setter 1,
4 and the processor 16 are all connected online, and various setting information such as image data, plate thickness, plate size, and type (plate type) of the image forming material input to the personal computer 10 are online. Can be output up to

The personal computer 10 includes, for example, an application that edits an image read from image reading means such as a scanner while displaying the image on a display, creates characters and images on the display, and creates an image to be printed. Is installed. This application outputs an image created by a user to the workstation 12 as vector-format image data such as an outline, a drawing command for designating an area ratio of a filled area, a transmittance of the filled area, and the like.
Further, various setting information such as a plate type, a plate thickness, and a plate size of an image forming material to be exposed, which are input by a user from a keyboard at the same time as the creation of an image, are written in text data together with the vector format image data. Is output to the workstation 12.

The workstation 12 has a raster image processor (hereinafter referred to as RIP) and driver software for the platesetter 14 installed therein. The RIP interprets vector-format image data and develops it as an array of dots having gradations, and is a TIFF-format file (hereinafter referred to as a TIFF file) or GIF.
This is an application for converting image data in a raster format such as a file. In the present embodiment, the image data in a vector format is converted into a TIFF file including a header portion in a tag format and an image data portion.

The driver software of the plate setter 14 converts various setting information such as the plate type, plate thickness, and plate size of the TIFF file and the text-form image forming material into an image format that can be analyzed by the plate setter 14, and converts the information into a plate setter. 14 is software to be output.

Therefore, the workstation 12 converts the vector-format image data such as the drawing command input from the personal computer 10 into a TIFF file, and then converts the TIFF file and the plate type, plate thickness, and plate size of the image forming material. The driver software of the platesetter 14 sends various setting information such as
After being converted into an image format that can be analyzed by the above, the image is output to the platesetter 14.

The plate setter 14 includes a ROM and a RAM.
And a setter control section 18 composed of a CPU.
Various programs for controlling the plate setter 14 are stored in the ROM, and a TIFF in an image format that can be analyzed by the plate setter 14 is stored in the RAM.
The file and various setting information are temporarily stored.

The CPU calls various programs from the ROM, and reads T from the RAM based on the programs.
Based on the IFF file and the various kinds of setting information described above, for example, a control signal for controlling a transport speed of a transport unit (not shown) of the plate setter 14, an on / off drive signal of a laser light source (not shown), and a light amount A variety of control signals such as a laser drive signal for performing the adjustment are generated, and the driving of the platesetter 14 is controlled by the various control signals. As a result, the plate setter 14 can use the personal computer 1
The exposure process of the image forming material 110 is performed under the optimum condition according to the image selected on the image No. 0. This is the above-mentioned exposure step for exposing an image. In addition, since the exposure processing of the plate setter 14 is publicly known, detailed description is omitted here.

Further, a driver software of the processor 16 is installed in the ROM of the setter control unit 18, and various setting information such as a plate type, a plate thickness, and a plate size are stored in the ROM of the processor 16. After converting into a format that can be analyzed by the above, it is output to the processor 16.

The processor 16 includes, as shown in FIG.
Generally, the heating unit 20, the first washing unit 22, the developing unit 24,
The image-forming material, which has been exposed to the image, is first washed by the heating unit 20 by a transport mechanism including a second washing unit 26, a finisher unit 28, a drying unit 29, and a processor control unit 30. In this configuration, the sheet is transported in the order of the section 22, the developing section 24, the second washing section 26, the finisher section 28, and the drying section 29.

The heating unit 20 comprises a pair of pull-in rollers 31 for rotating the image forming material between the pair of rollers while holding the image forming material therebetween, thereby drawing the exposed image forming material 110 into the processor 16, and a heating device 32. By heating the image forming material 110 before the development processing, the image area in the photosensitive layer of the image forming material 110 is heated.
(I.e., accelerate the curing of the exposed areas).

As shown in FIG. 2, the heating device 32 includes a heating unit 34 and an image forming material 1 on the lower surface side of the image forming material 110.
And a plurality of transport rollers 36 for transporting the heating control unit 3
8 and a temperature detection sensor 40 (see FIG. 1).

The temperature detection sensor 40 is connected to the processor 16
The temperature in the exposure section of the plate setter 14 provided in the preceding stage or the temperature of the image forming material 110 before the heat treatment, converts the temperature change into an electrical level change, and outputs it as a temperature signal Vt. A warm sensation element can be used. The heating conditions in the heating section are preferably controlled by the plate information of the image forming material, as described below.
In the range of 120 ° C., the heating time needs to be in the range of 1 second to 20 seconds. When the heating temperature is lower than 60 ° C., the effect of improving the printing durability is small, and when the heating is performed at a high temperature exceeding 120 ° C., a residual film is easily generated in the non-image area. A preferred heating temperature range is 70C to 110C. As for the heating time, a short heating time of less than 1 second has a small effect on the printing durability, and an undesired curing reaction of the photosensitive layer occurs by heating for more than 20 seconds for a long time. It is easy for stains to occur in the part. Preferred heating times range from 5 seconds to 15 seconds.

Here, the means for controlling the heating conditions based on the plate information will be described. The version information referred to in the present invention is:
It contains at least one of the plate thickness, plate size, and plate type (such as the composition constituting the photosensitive layer), and when such information is used for determining heating conditions, such plate information is used by the user Rather than manually inputting, the heating conditions are determined based on the plate information input as information necessary for processing the image forming material in the apparatus at the previous stage, so that forgetting to change or inputting mistakes, etc. Therefore, it is possible to surely heat the image forming material to be heated under the optimal heating condition without causing the operation error of the above.

The plate thickness is, for example, 0.12 mm,
0.15mm, 0.2mm, 024mm, 0.3mm,
There are types such as 0.4 mm. As the plate size, the small plate is, for example, 254 mm × 391 mm, the medium plate is, for example, 650 mm × 550 mm in length × width, and the large plate is, for example, 1030 mm × length × width. 800mm or 1130mm
× 930 mm.

As a typical example of the plate size and thickness, the plate size is 254 mm × 391 mm and the thickness is 0.1 mm.
12mm lithographic printing plate or plate size 650mm x 55
A flat printing plate with a thickness of 0 mm and a thickness of 0.24 mm, or a plate size of 1030 mm x 800 mm or 1130 mm x 930 m
and a flat printed board having a thickness of 0.3 mm. of course,
It is not limited to these plate sizes and thicknesses.

When the thickness of the lithographic printing plate is input as the plate information, if the thickness of the lithographic printing plate is large, the thickness of the aluminum plate as the support is also large. The heating capacity is controlled to be large. Also, when the thickness of the lithographic printing plate is thin, the thickness of the aluminum plate as the support is also thin, so that the heat capacity is smaller than when the thickness of the aluminum plate is thick. The heating capacity to be controlled is controlled to be smaller than when the thickness of the lithographic printing plate is large. Thereby, the surface temperature of the lithographic printing plate can be made uniform regardless of the thickness. In addition,
The heating capacity is a value determined by the product of the heating temperature and the heating time.

When a plate size is input as plate information, if the planographic printing plate has a large width and a long length (hereinafter, referred to as L size), the area of the aluminum plate is small. As the heat capacity increases, the heat capacity is large, and the heating capacity applied to the lithographic printing plate from the heating means is controlled to be large.
It is called S size. In the case of the planographic printing plate of (1), since the heat capacity is small, the heating capacity applied to the planographic printing plate is controlled to be smaller than that of the L-sized planographic printing plate.

Further, when a plate type is input as plate information, for example, when a resin which is relatively hard to undergo a polymerization reaction is used, the heating conditions are set so that the heating temperature is increased and the heating time is shortened. Once determined, control is performed so that a sufficiently large heating capacity is provided to improve the printing durability. In addition, when the plate type is made of a high printing durability resin, sufficient heating is required to improve the printing durability, but when the heating temperature is increased, the solubility of the protective layer is reduced, Since there is a possibility that thermal polymerization may occur and development failure may occur, the heating conditions are determined so as to secure the necessary heating capacity by increasing the heating time without increasing the heating temperature so as to improve the printing durability. Control to provide a sufficiently large heating capacity. Furthermore, when the plate type is for high image quality, determine the heating temperature and the heating time so as to have a medium heating capacity,
Control is performed so that the dot quality is made uniform by uniformly heating the entire surface.

For example, for plate type A, the required heating capacity is 8
Assuming that the temperature is 0 ° C. or more and 120 ° C. or less and 10 seconds, the minimum heat amount actually required is 80 ° C. for 10 seconds or 100 ° C. for 5 seconds. As described above, if the heating temperature is increased, the solubility of the protective layer may be reduced, or thermal polymerization of the photosensitive layer may occur, resulting in poor development. Therefore, it is necessary to adjust the heating temperature not to be so high. In some cases, 10 seconds at 80 ° C,
When the heating temperature may be increased, the temperature is set to 100 ° C. for 5 seconds. The upper limit temperature varies depending on the components constituting the photosensitive layer, but according to the method of the present invention, the upper limit is 120 ° C.
It is. There is an appropriate temperature range for each type of plate used, but it is easy for those skilled in the art to determine an appropriate temperature range for the photosensitive layer because its constituent components are clear.

Here, the heating control section 38 used for controlling the heating conditions is composed of a RAM, a ROM and a CPU.
When the detection result from the temperature detection sensor 40 is output and the above-described various setting information is input to the plate setter 14, the various setting information is acquired online before starting the heating control.

Various setting information obtained from the plate setter 14 is stored in the RAM. The ROM stores a table of standard heating capacity (product of heater output and heating time) given to the image forming material in accordance with the combination of the plate type, plate thickness, and plate size of the image forming material. For example, the table of the standard heating capacity is divided into a short run and a long run, and the standard heating capacity is determined according to the combination of the thickness and the size.

The relationship between the heating capacities is that, in the case of a short run, the larger the size, the larger the heat capacity and the larger the heating, and the larger the thickness, the larger the heat capacity. Become. For the same reason, in the case of a long run, the larger the size, the larger the heat capacity and the larger the heating, and the thicker the thickness, the larger the heat capacity.

Further, since it is necessary to apply a larger amount of heat to a long run than to a short run, there is a relationship that the smallest amount of heat in a long run is larger than the largest amount of heat in a short run.

In the ROM, based on the various setting information stored in the RAM, for example, a standard heating capacity optimum for the read setting information is selected from the standard heating capacity table as described above. , And a temperature detection sensor 40
When the temperature signal Vt is large, that is, when the detected temperature is high, the temperature of the image forming material itself is also high, so that the heating capacity smaller than the standard heating capacity is given to the image forming material. By correcting the standard heating capacity, the temperature signal Vt from the temperature detection sensor 40 is small,
That is, when the detected temperature is low, the temperature of the image forming material itself is also low, so that the standard heating capacity is corrected so as to give the image forming material a heating capacity that is larger than the standard heating capacity, A heating capacity determination program shown in FIG. 3 for generating a control signal Vc for controlling the heater driving voltage based on the corrected heating capacity is stored.

Here, the control of the drive voltage executed by the CPU of the heating control unit 38 will be described with reference to the flowchart of FIG. In step 200, first,
The various setting information stored in the RAM is read.

In the next step 202, a standard heating capacity is selected from a standard heating capacity table based on various setting information read from the RAM. For example, when the standard heating capacity table described above is used, if the plate type is short run, the plate size is M size, and the thickness is d2, an appropriate condition is selected from a heating capacity table prepared in advance.

In the next step 204, in accordance with the temperature signal Vt input from the temperature detection sensor 40, the standard heating capacity is set to be larger, smaller, or one of the standard heating capacities. Correct heating capacity of.

In the next step 206, a control signal Vc to be supplied to a heater driving circuit (not shown) and a transport control signal for controlling the transport speed of the image forming material 110 by the transport mechanism are generated so that the adjusted heating conditions are obtained. Then, this routine ends. The control signal Vc controls the heater output and the transport speed of the heating device 32 so that the heating conditions are adjusted.

For example, black-coated 500
M size high-quality image formation using a heating device in which two halogen lamp heaters of W are provided at a distance of 50 mm from the image forming material and having a 0.3 mm thick aluminum substrate as the image forming material The case where the material is used and the conveying speed of the image forming material is 19 mm / sec will be described.

In the above conditions, the standard temperature condition is that the temperature detected by the temperature detection sensor 40 is 25 ° C.
(Ie, room temperature), the output of the heating device 32 is 470 W
When the temperature is lower than 25 ° C., the output of the heating device 32 is made larger than that at 25 ° C. to increase the amount of heat given to the image forming material 110. When the temperature is higher than 25 ° C., the output of the heating device 32 is increased. Is made smaller than that at 25 ° C. to reduce the amount of heat applied to the image forming material 110.

Specifically, when the temperature detected by the temperature detection sensor 40 is 10 ° C., the output of the heating device 32 is
0 W, when the temperature is 15 ° C., the output of the heating device 32 is set to 5
When the temperature is 30 W, the output of the heating device 32 is 500 W when the temperature is 20 ° C., and when the temperature is 30 ° C., the output of the heating device 32 is 440 W.

Instead of storing a standard heating capacity table, a heating capacity conversion characteristic graph table individually determined according to various setting information is stored, and a heating capacity corresponding to the read various setting information is stored. It is also possible to read the conversion characteristic graph and calculate the heating capacity corresponding to the temperature detected by the temperature detection sensor 40 from the graph.

As described above, the heating means of the present embodiment determines the heating condition based on various setting information inputted online from the plate setter 14, thereby reducing the surface temperature of the image forming material 110. Plate type, plate thickness,
Under the optimal heating conditions for the combination of plate sizes, the temperature can be made uniform regardless of the temperature in the exposed portion of the plate setter 14 or the temperature of the image forming material 110 before the heat treatment. Inconvenience can be solved and favorable heat treatment can be performed.

Further, since there is no need for the user to input various setting information, it is possible to avoid the occurrence of loss due to an operation error or the like, and it is possible to efficiently switch to the next heating condition. The processing efficiency over the processing can also be improved.

The image forming material 110 that has been subjected to the heat treatment in the heating section 20 is conveyed to the first washing section 22 provided at the subsequent stage.

As shown in FIG. 2, the first washing section 22 includes a pair of pull-in rollers 62 and a first washing water supply in the first washing tank 60 in order from the upstream side along the conveying direction of the image forming material 110. A nozzle 64a, a first rotating brush roller 66 and a backup roller 67, a second cleaning water supply nozzle 64b,
An overcoat layer formed on the outermost surface of the image forming material 110 is removed by washing with water before development with a pair of delivery rollers 68.

Further, a first overflow pipe 61 is provided in the first washing tank 60, and when the liquid level of the washing water accumulated in the first washing tank 60 exceeds a predetermined level, the first washing water is discharged. It is adjusted so that it flows into the overflow pipe 61 and is guided to the washing water tank 63 so that a constant amount of washing water is always held in the first washing tank 60. Wash water tank 6
3, a pump P is provided, and the pump P pumps up the internal cleaning water and supplies it to the first cleaning water supply nozzle 64a and the second cleaning water supply nozzle 64b.

The first rinsing section 2 is driven by the pull-in roller pair 62.
The heated image forming material 110 drawn into 2 is sandwiched between the first first rotating brush roller 66 and the backup roller 67 in a state where the cleaning water is supplied to the surface by the first cleaning water supply nozzle 64a. When transported
The surface is polished by the first rotating brush roller 66,
The top overcoat layer of the image forming material 110 is removed.

A second stage is provided after the first rotating brush roller 66.
A cleaning water supply nozzle 64b is provided, and is removed by the first rotating brush roller 66 attached to the surface of the image forming material 110 by the cleaning water supplied from the second cleaning water supply nozzle 64b to the surface of the image forming material 110. The residue of the overcoat layer thus removed is removed. As a result, the overcoat layer is removed from the surface of the image forming material 110, and the image forming material 110 is sent out to the developing unit 24 provided after the first washing unit 22 by the sending roller pair 68. If the image forming material used does not have an overcoat layer, this washing step can be omitted.

As shown in FIG. 2, the developing section 24 includes a pair of pull-in rollers 72, a developing solution spray nozzle 74, and a dilution water spray in the developing tank 70 in order from the upstream side along the conveying direction of the image forming material 110. Nozzle 76, first spray pipe 7
8, a first rotating brush roller 71a, a second rotating brush roller 71b, and a delivery roller pair 75, and perform a developing process by immersing the image forming material 110 in a developing solution.

The pull-in roller pair 72 is connected to the first washing section 22.
Is drawn into the developing unit 24 at an angle in the range of about 15 ° to 31 ° with respect to the horizontal direction. The developer injection nozzle 74 applies the developer pumped up from the developer storage tank 82 by the pump P to the developing tank 70.
Inject into. The drive of the pump P is controlled by the processor control unit 30. Similarly, the dilution water injection nozzle 76 injects the dilution water pumped up from the water storage tank 84 by the pump P into the development tank 70. The drive of the pump P is also controlled by the processor control unit 30.

The processor controller 30 controls the amount of the developing solution and the amount of the diluting water to be supplied according to the area ratio of the image forming area. In other words, the larger the developing area, the faster the deterioration of the developing solution. Therefore, the dilution water is reduced and the developing solution is supplied so as to increase, and the smaller the developing area, the slower the deterioration of the developing solution. The concentration of the developing solution is adjusted by reducing the dilution water and supplying the developing solution so as to increase.

Further, a second overflow pipe 79 for collecting the developing solution overflowing from the developing tank 70 is provided in the developing tank 70, and the liquid level of the developing solution accumulated in the developing tank 70 is maintained at a predetermined level. Is exceeded, the developer flows into the second overflow pipe 79 and the waste liquid tank 8
The developing tank 70 is adjusted so that a constant amount of the developing solution is always held in the developing tank 70.

As a base of the developing solution and the replenishing solution used in the image forming method of the present invention, a conventionally known alkaline aqueous solution can be used. It is preferable to use a weak alkaline aqueous solution in the range of 12, and more preferably a weak alkaline aqueous solution having a pH of about 8 to 10. The conventional general-purpose developer has a pH of 12.5 to 13.5, but according to the method of the present invention, only the curing of the image area is promoted without affecting the unexposed area. Even if a weak alkaline aqueous solution is used, there is no concern that a residual film is generated, and there is also an advantage that good development can be performed without impairing the printing durability of the image area.

As a developing solution, a so-called “silicate developing solution” using an alkali silicate and containing silicon dioxide,
A non-reducing sugar and a base, or a surfactant and a base,
There are "non-silicate developers" that are substantially free of silicon dioxide. Here, “substantially” means that the presence of trace amounts of silicon dioxide as unavoidable impurities and by-products is allowed. In the developing step of the image forming material of the present invention, any of the above-mentioned developing solutions can be applied, but from the viewpoint of the effect of suppressing the generation of scratches, it is preferable to use a non-silicate developing solution.

First, the "silicate developer" will be described. The alkali silicate exhibits alkalinity when dissolved in water, and examples thereof include alkali metal silicates such as sodium silicate, potassium silicate, and lithium silicate, and ammonium silicate. The alkali silicate may be used alone or in combination of two or more. The aqueous alkali solution contains silicon oxide SiO _{2 as} a component of silicate and alkali oxide M ₂ O (M
Represents an alkali metal or ammonium group. ) Can be easily adjusted by adjusting the mixing ratio and the concentration, for example, an alkali metal described in JP-A-54-62004 and JP-B-57-7427. Silicates are used effectively. Among the alkali aqueous solutions, those having a mixing ratio (SiO ₂ / M ₂ O: molar ratio) of the silicon oxide SiO ₂ and the alkali oxide M ₂ O of 0.5 to 3.0 are preferable, and 1.0 to 3.0. 2.
0 is more preferred. When the SiO ₂ / M ₂ O is 0.
If it is less than 5, the alkali strength increases,
When a general-purpose aluminum plate or the like is etched as a support for a lithographic printing original plate, a bad effect may occur, and when it exceeds 3.0, developability may be reduced.

The concentration of the alkali silicate in the developer is 1 to 10% by weight based on the weight of the aqueous alkali solution.
Is preferably 3 to 8% by weight, and most preferably 4 to 7% by weight. If the concentration is less than 1% by weight, the developability and the processing capacity may be reduced. If the concentration is more than 10% by weight, precipitates and crystals are easily formed. And it may interfere with waste liquid treatment.

Next, the “non-silicate developer” will be described. Non-silicate developers suitable for the method of the present invention include:
As described above, a non-reducing sugar is composed of a non-reducing sugar and a base, or a surfactant and a base, wherein the non-reducing sugar has no free aldehyde group or ketone group, and thus has no reducing ability. Which are classified into trehalose-type oligosaccharides in which reducing groups are bonded to each other, glycosides in which reducing groups of saccharides are bonded to non-saccharides, and sugar alcohols obtained by hydrogenating and reducing saccharides. In the present invention, any of these can be suitably used.

The trehalose-type oligosaccharides include, for example, saccharose and trehalose, and the glycosides include, for example, alkyl glycosides, phenol glycosides, and mustard oil glycosides. Examples of the sugar alcohol include D, L-arabit, ribit, xylit, D, L-sorbit, D, L-annit,
D, L-idit, D, L-talit, zuricit, allozurcit and the like. Further, maltitol obtained by hydrogenation of a disaccharide, a reductant (reduced starch syrup) obtained by hydrogenation of an oligosaccharide, and the like can also be preferably mentioned.

Among the above, the non-reducing sugars are preferably sugar alcohols and saccharose, and among them, D-sorbitol, saccharose and reduced starch syrup are more preferable in that they have a buffering action in an appropriate pH range. These non-reducing sugars may be used alone or in combination of two or more, and the ratio in the developer is preferably 0.1 to 30% by weight,
1-20% by weight is more preferred.

Among the above, non-reducing sugars are preferably sugar alcohols and saccharose, and among them, D-sorbitol, saccharose, and reduced starch syrup are more preferable because they have a buffering action in an appropriate pH range. These non-reducing sugars may be used alone or in combination of two or more, and the ratio in the developer is preferably 0.1 to 30% by weight,
1-20% by weight is more preferred.

The alkali silicate or the non-reducing sugar can be combined with an alkali agent as a base by appropriately selecting from those conventionally known. Examples of the alkaline agent include sodium hydroxide, potassium hydroxide,
Lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate And inorganic alkali agents such as ammonium bicarbonate, sodium borate, potassium borate and ammonium borate, potassium citrate, tripotassium citrate and sodium citrate. In addition, monomethylamine, dimethylamine, trimethylamine,
Monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine,
Organic alkali agents such as triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanol amici, ethyleneimine, ethylenediamine, and pyridine can also be suitably mentioned. These alkaline agents may be used alone or in combination of two or more.

Of these, sodium hydroxide and potassium hydroxide are preferred. The reason is that adjusting the amount of addition to the non-reducing sugar enables pH adjustment in a wide pH range. Also, trisodium phosphate,
Tripotassium phosphate, sodium carbonate, potassium carbonate, and the like are also preferable because they themselves have a buffering action.

The non-silicate developer which can be suitably used in the present invention may further include a weakly alkaline aqueous solution of a surfactant and a base having a pH of 7 to 12. Preferred surfactants that can be used in this developer include polyoxyethylene alkyl ethers,
Polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol fatty acid partial esters, propylene glycol monofatty acid Esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, polyoxyethylenated castor oil, polyoxyethylene Glycerin fatty acid partial esters, fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamines, Polyoxyethylene alkyl amines,
Nonionic surfactants such as triethanolamine fatty acid esters and trialkylamine oxides, fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, alkanesulfonic acid salts, dialkylsulfosuccinic acid ester salts, linear alkylbenzenesulfonic acid salts , Branched-chain alkylbenzenesulfonates, alkylnaphthalenesulfonates, alkylphenoxypolyoxyethylenepropylsulfonates, polyoxyethylenealkylsulfophenylether salts, N-methyl-N-oleyltaurine sodium salt, N-alkylsulfosuccinic acid Monoamide disodium salts, petroleum sulfonates, sulfated castor oil, sulfated tallow oil, sulfates of fatty acid alkyl esters, alkyl sulfates, polyoxy Tylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkyl phenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ethers phosphates, Anions such as polyoxyethylene alkyl phenyl ether phosphates, partially saponified styrene-maleic anhydride copolymers, partially saponified olefin-maleic anhydride copolymers, and naphthalene sulfonate formalin condensates Surfactants,

Cationic surfactants such as alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylenepolyamine derivatives;
Examples include amphoteric surfactants such as carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfates, and imidazolines. Among the surfactants mentioned above, those with polyoxyethylene can be read as polyoxyalkylenes such as polyoxymethylene, polyoxypropylene, and polyoxybutylene, and these surfactants are also included. You.

Preferred bases include carbonates, bicarbonates, and amines. Suitable carbonates and bicarbonates include alkali metal carbonates and bicarbonates, alkaline earth metal carbonates and bicarbonates, ammonium carbonates and bicarbonates, and the like. Particularly preferred are sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate and the like. These carbonates and bicarbonates may be anhydrous or hydrated. Further, two or more kinds of carbonates and bicarbonates can be used as a mixture. Preferred amines include the amines described above.

Known additives can be used in the developer used in the method of the present invention, if necessary, as long as the effects of the present invention are not impaired. Examples of such additives include surfactants, reducing agents such as sodium salts and potassium salts of inorganic acids such as hydroquinone, resorcinol, sulfurous acid and bisulfite, organic carboxylic acids, organic solvents such as benzyl alcohol, and defoaming agents. And water softeners.

When developing with an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than the developing solution is added to the developing solution, so that the developing solution in the developing tank can be replaced for a long time. It is known that large quantities of lithographic printing plates can be processed. In the present invention, this replenishment method is preferably applied.
It is preferably in the range of 12.

In this embodiment, for the sake of explanation, one personal computer is connected to the workstation 12 online. However, the number of computers is not limited to one, and a plurality of personal computers can be connected online. Similarly,
In this embodiment, for the sake of explanation, one processor 16 is connected online to the platesetter 14, but it is needless to say that the number of processors 16 is not limited to one.
4 can connect a plurality of personal computers online.

When a plurality of personal computers are connected online to the plate setter 14, conditions such as changing heating conditions can be set more efficiently, so that the loss time can be reduced and the efficiency is improved.

In this embodiment, the image data output from the workstation is a TIFF file. Of course, the present invention is not limited to a TIFF file. A standard PPF file containing image data such as a PPF file composed of transfer characteristic curves, types of registration marks, color density information for quality control of position data, and information of trimming marks and cutting. Formatted image data can be used.

In the present embodiment, the plate setter 14 and the processor 16 are connected online. However, the present invention is not limited to the online connection, and the plate setter 14 and the processor 16 may be connected via a communication line or used as a storage medium. The information of the plate setter 14 may be stored as setter information, and the storage medium may be read by the processor 16 to transfer the setter information.

In this embodiment, the case where the ROM stores a standard heating capacity table corresponding to the combination of the plate type, the plate thickness, and the plate size has been described. At least one of a heating capacity table, a standard heating capacity table according to the plate thickness, and a standard heating capacity table according to the plate size is stored, and the standard heating capacity is stored based on the stored table. It may be determined.

The image forming method of the present invention comprises the steps of:
(A) an infrared absorber, (B) a radical generator,
The present invention is applied to a negative image forming material provided with a photosensitive layer containing (C) a radical polymerizable compound and (D) a binder polymer. Further, it is preferable to form an overcoat layer on the photosensitive layer to prevent polymerization inhibition of the (C) radical polymerizable compound by oxygen and to protect the photosensitive layer.

Here, the negative type image forming material will be described. This image forming material is used as a photosensitive layer as (A)
The photosensitive layer includes an infrared absorber, (B) a radical generator, (C) a radical polymerizable compound, and (D) a binder polymer. Such an image forming material undergoes photo-thermal conversion of the (A) infrared absorbing agent in the exposed portion by imagewise exposure with an infrared laser, and the generated heat decomposes (B) the radical generator to generate radicals. As a result, the photosensitive layer containing (C) the radical polymerizable compound and (D) the binder polymer cures to form an image area. Thereafter, by developing with a weak alkaline aqueous solution as described above, the uncured unexposed photosensitive layer is removed, and a non-image portion is formed.

The components of the photosensitive layer will be described sequentially. [(A) Infrared absorbing agent] An object of the present invention is to record an image with a laser emitting infrared rays. To this end, it is essential to use an infrared absorber. The infrared absorbent has a function of converting the absorbed infrared light into heat.
The heat generated at this time decomposes the radical generator to generate radicals. The infrared absorber used in the present invention is a dye or pigment having an absorption maximum at a wavelength of 760 nm to 1200 nm.

As the dye, commercially available dyes and known dyes described in literatures such as “Dye Handbook” (edited by the Society of Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, and metal thiolate complexes Is mentioned.

Preferred dyes include, for example, those described in
Cyanine dyes described in JP-A-8-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, etc .;
No. 96, JP-A-58-181690, JP-A-58-1
No. 94595, etc., methine dyes described in
8-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59-73996,
Naphthoquinone dyes described in JP-A-60-52940 and JP-A-60-63744;
Squarylium dyes described in No. 12792, etc.,
Cyanine dyes described in British Patent 434,875 and the like can be mentioned.

Further, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) described in US Pat. No. 3,881,924 is also preferable. Pyrylium salt, JP-A-57-142645
No. (U.S. Pat. No. 4,327,169) described in JP-A-58-181051, JP-A-58-220143, JP-A-59-41363, and JP-A-59-41363.
Nos. -84248, 59-84249, 59-14
Nos. 6063 and 59-146061, pyranyl compounds, cyanine dyes described in JP-A-59-216146, pentamethinethiopyrylium salts described in U.S. Pat. No. 4,283,475, and the like. Fairness 5-13
Pyrylium compounds disclosed in JP-A-514 and JP-A-5-19702 are also preferably used.

Further, as another preferred example of the dye, US Pat. No. 4,756,993 discloses formula (I):
Near-infrared absorbing dyes described as (II) can be mentioned.

Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and nickel thiolate complexes. Further, a cyanine dye is preferable, and a cyanine dye represented by the following general formula (I) is most preferable.

[0084]

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In the general formula (I), X ¹ is a halogen atom,
Or an X ² -L ^1. Here, X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms. R ¹ and R ² each independently represent a hydrocarbon group having 1 to 12 carbon atoms. From the viewpoint of storage stability of a photosensitive layer coating liquid, R ¹ and R ² are preferably a hydrocarbon group having two or more carbon atoms, further, R ¹ and R ²
And particularly preferably combine with each other to form a 5- or 6-membered ring.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Preferred examples of the substituent include a hydrocarbon group having 12 or less carbon atoms, a halogen atom, and an alkoxy group having 12 or less carbon atoms. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different, and represent a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms,
Examples include a carboxyl group and a sulfo group. R ⁵ , R ⁶ , R
⁷ and R ⁸ may be the same or different,
It represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the viewpoint of availability of raw materials, a hydrogen atom is preferable. Z ^1- represents a counter anion. However, when any of R ^{1 to} R ⁸ is substituted with a sulfo group, Z ^1- is not required. Preferred Z ¹⁻ is, from the storage stability of the photosensitive layer coating solution, a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion,
And sulfonate ions, particularly preferably perchlorate ion, hexafluorophosphate ion and arylsulfonate ion.

In the present invention, specific examples of the cyanine dye represented by the general formula (I) which can be suitably used include paragraph [0] of Japanese Patent Application No. 11-310623.
017] to [0019].

The pigment used in the present invention includes:
Commercial Pigment and Color Index (CI) Handbook,
"Latest Pigment Handbook" (edited by Japan Pigment Technical Association, 1977), "Latest Pigment Application Technology" (CMC Publishing, 1986), "Printing Ink Technology" CMC Publishing, 1984)
Can be used.

The pigments include black pigment, yellow pigment, orange pigment, brown pigment, red pigment, purple pigment,
Blue pigment, green pigment, fluorescent pigment, metal powder pigment, etc.
Polymer-bound dyes. Specifically, insoluble azo pigments, azo lake pigments, condensation azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments,
Perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, dyeing lake pigments,
Azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like can be used.
Preferred among these pigments is carbon black.

These pigments may be used without surface treatment, or may be used after surface treatment. Examples of the surface treatment include a method of surface coating a resin or wax, a method of attaching a surfactant, and a method of bonding a reactive substance (eg, a silane coupling agent, an epoxy compound, a polyisocyanate, etc.) to the pigment surface. Can be considered. The above surface treatment methods are described in "Properties and Applications of Metallic Soap" (Koshobo),
It is described in "Printing Ink Technology" (CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986).

The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm.
Is preferably within the range. Pigment particle size 0.01μ
If it is less than m, the dispersion is not preferred in terms of stability in the coating solution of the image-sensitive layer.

As a method for dispersing the pigment, a known dispersion technique used in the production of ink or toner can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. For details, refer to “Latest Pigment Application Technology” (CMC Publishing, 1
986).

These infrared absorbers may be added to the same layer as the other components or may be added to another layer provided there. However, when a negative type image forming material is prepared, It is preferable that the optical density of the photosensitive layer at the absorption maximum in the wavelength range of 760 nm to 1200 nm is between 0.1 and 3.0. Outside of this range, sensitivity tends to decrease. Since the optical density is determined by the amount of the infrared absorbing agent added and the thickness of the recording layer, a predetermined optical density can be obtained by controlling both conditions. The optical density of the recording layer can be measured by a conventional method. As a measuring method, for example, on a transparent or white support, a coating layer after drying is formed to a recording layer having a thickness appropriately determined in a range necessary for a lithographic printing plate, and a transmission type optical densitometer is used. Examples include a method of measuring, a method of forming a recording layer on a reflective support such as aluminum, and measuring a reflection density.

[(B) Radical generator] The radical generator used in the present invention refers to a compound which is used in combination with (A) an infrared absorber and generates a radical when irradiated with an infrared laser. Examples of the radical generator include an onium salt, a triazine compound having a trihalomethyl group, a peroxide, an azo-based polymerization initiator, an azide compound, and quinonediazide. An onium salt is preferable because of its high sensitivity. The onium salt that can be suitably used as a radical polymerization initiator in the present invention will be described. Preferred onium salts include iodonium salts, diazonium salts, and sulfonium salts. In the present invention,
These onium salts function not as acid generators but as radical polymerization initiators. Onium salts suitably used in the present invention are onium salts represented by the following general formulas (III) to (V).

[0095]

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In the formula (III), Ar ¹¹ and Ar ¹² each independently represent an aryl group having 20 or less carbon atoms which may have a substituent. When the aryl group has a substituent, preferred substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or a 12 or less carbon atom. Aryloxy groups. Z ^11- represents a counter ion selected from the group consisting of a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, and is preferably a perchlorate ion or a hexafluorophosphate. And arylsulfonate ions.

In the formula (IV), Ar ²¹ represents an optionally substituted aryl group having 20 or less carbon atoms. Preferred substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, an aryloxy group having 12 or less carbon atoms, and a 12 or less carbon atom. Alkylamino group, dialkylamino group having 12 or less carbon atoms, 1 carbon atom
An arylamino group having 2 or less or a diarylamino group having 12 or less carbon atoms is exemplified. Z ^{21 -} is Z ^11-
Represents a counter ion having the same meaning as

In the formula (V), R ³¹ , R ³² and R ³³ may be the same or different and represent a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, and an aryloxy group having 12 or less carbon atoms. Z ^31- represents a counter ion having the same ^meaning as Z ^11- .

In the present invention, specific examples of onium salts that can be suitably used as a radical generator include:
Paragraph number [003 of Japanese Patent Application No. 11-310623]
0] to [0033].

The radical generator used in the present invention preferably has a maximum absorption wavelength of 400 nm or less, more preferably 360 nm or less. By setting the absorption wavelength in the ultraviolet region, the image forming material can be handled under a white light.

These radical generators are used in an amount of 0.1 to 50% by weight, preferably 0.1 to 50% by weight, based on the total solid content of the coating solution for the photosensitive layer.
It can be added to the photosensitive layer coating solution at a ratio of 5 to 30% by weight, particularly preferably 1 to 20% by weight. If the amount is less than 0.1% by weight, the sensitivity is lowered, and if it exceeds 50% by weight, the non-image area is stained during printing. One of these radical generators may be used alone, or 2
More than one species may be used in combination. In addition, these radical generators may be added to the same layer as other components, or another layer may be provided and added thereto.

[(C) Radical polymerizable compound] The radical polymerizable compound used in the present invention is a radical polymerizable compound having at least one ethylenically unsaturated double bond, and has a terminal ethylenically unsaturated bond. At least one
, Preferably two or more compounds. Such compounds are widely known in the industrial field, and they can be used in the invention without any particular limitation. These have chemical forms such as, for example, monomers, prepolymers, ie, dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) and esters and amides thereof, and are preferred. As the ester, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and an aliphatic polyamine compound are used. Further, an unsaturated carboxylic acid ester having a nucleophilic substituent such as a hydroxyl group, an amino group or a mercapto group, an addition reaction product of an amide with a monofunctional or polyfunctional isocyanate, an epoxy, a monofunctional or A dehydration-condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an isocyanate group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, and further, halogen A substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving group such as a group or a tosyloxy group with a monofunctional or polyfunctional alcohol, amine or thiol is also suitable.
As another example, it is also possible to use a group of compounds in which the above unsaturated carboxylic acid is replaced with unsaturated phosphonic acid, styrene or the like.

Specific examples of the radically polymerizable compound, which is an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid, such as acrylic acid ester, methacrylic acid ester, itaconic acid ester, crotonic acid ester, isocrotonic acid ester and maleic acid ester For example, Japanese Patent Application No. Hei 11-3
No. 10623, paragraphs [0037] to [004]
2], and these can be applied to the present invention.

Examples of other esters include aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, JP-A-59-5240 and JP-A-59-5240. 59-524
1, those having an aromatic skeleton described in JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used.

Specific examples of the amide monomer of the aliphatic polyamine compound and the unsaturated carboxylic acid include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6- Hexamethylene bis-methacrylamide,
Examples include diethylenetriaminetrisacrylamide, xylylenebisacrylamide, xylylenebismethacrylamide, and the like.

Examples of other preferable amide-based monomers include those having a cyclohexylene structure described in JP-B-54-21726.

A urethane-based addition-polymerizable compound produced by an addition reaction between an isocyanate and a hydroxyl group is also suitable.
JP-A-8-41708 discloses a polyisocyanate compound having two or more isocyanate groups in one molecule to which a vinyl monomer having a hydroxyl group represented by the following formula (VI) is added. And vinyl urethane compounds containing at least two polymerizable vinyl groups.

Formula (VI) CH ₂ ＣC (R ⁴¹ ) COOCH ₂ CH (R ⁴² ) OH (where R ⁴¹ and R ⁴² represent H or CH ₃ )

Further, urethane acrylates described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, and JP-B-58-16765 can be used.
No. 49860, No. 56-17654, No. 62
Urethane compounds having an ethylene oxide skeleton described in JP-B-39417 and JP-B-62-39418 are also suitable.

Further, radical polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277563, JP-A-63-260909 and JP-A-1-105238 may be used. good.

As another example, see JP-A-48-641.
No. 83, JP-B-49-43191, JP-B-52-30
No. 490, polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid as described in each publication. Also,
JP-B-46-43946, JP-B-1-40337,
Specific unsaturated compounds described in JP-B-1-40336,
Vinyl phosphonic acid compounds described in JP-A-2-25493 can also be mentioned. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Japan Adhesion Association Journal vol. 20, No. 7, pages 300-308 (198
(4 years) as photocurable monomers and oligomers can also be used.

These radical polymerizable compounds are:
Details of the method of use, such as what kind of structure is used, whether it is used alone or in combination, and how much is added, can be arbitrarily set in accordance with the final performance design of the recording material. For example, it is selected from the following viewpoints. From the viewpoint of sensitivity, a structure having a large content of unsaturated groups per molecule is preferable, and in many cases, a bifunctional or more functional structure is preferable. In order to increase the strength of the image area, that is, the cured film, a compound having three or more functional groups is preferable, and a compound having a different functional number and a different polymerizable group (for example, an acrylate compound, a methacrylate ester) It is also effective to control both the photosensitivity and the intensity by using a combination of a compound and a styrene compound. Compounds with large molecular weight and compounds with high hydrophobicity are excellent in sensitivity and film strength,
It may not be preferable in terms of development speed and precipitation in a developer. In addition, the selection and use of the radical polymer compound is also an important factor for the compatibility and dispersibility with other components (for example, a binder polymer, an initiator, a colorant, and the like) in the photosensitive layer. Use of low purity compounds, 2
The compatibility may be improved by the combined use of at least one compound. In addition, a specific structure may be selected for the purpose of improving the adhesion of the support, the overcoat layer, and the like. Regarding the compounding ratio of the radical polymerizable compound in the image recording layer, a higher ratio is advantageous in sensitivity, but if the ratio is too large, undesired phase separation occurs or the production process due to the stickiness of the image recording layer. (For example, poor production resulting from transfer of recording layer components and adhesion) and problems such as precipitation from a developer. From these viewpoints, the preferable compounding ratio of the radical polymerizable compound is, in many cases, 5 to 80% by weight, preferably 20 to 80% by weight, based on all components of the composition.
75% by weight. These may be used alone or in combination of two or more. In addition, the method of using the radical polymerizable compound can be arbitrarily selected from the viewpoint of the degree of inhibition of polymerization with respect to oxygen, resolution, fogging, refractive index change, surface tackiness, etc. Depending on the case, a layer structure and a coating method such as undercoating and overcoating may be performed.

[(D) Binder polymer] In the present invention, a binder polymer is further used. It is preferable to use a linear organic polymer as the binder. Any of such “linear organic polymers” may be used. Preferably, a linear organic polymer which is soluble or swellable in water or weakly alkaline water is selected to enable development with water or weakly alkaline water. The linear organic polymer is selected and used not only as a film forming agent for forming a photosensitive layer but also as a developer for water, weakly alkaline water or an organic solvent.
For example, when a water-soluble organic polymer is used, water development becomes possible. Examples of such a linear organic polymer include a radical polymer having a carboxylic acid group in a side chain, for example,
Nos. 9-44615, JP-B-54-34327, JP-B-58-12577, JP-B-54-25957, JP-A-54-92723, JP-A-59-53836, and JP-A-59-71048. Those described, that is, methacrylic acid copolymer, acrylic acid copolymer, itaconic acid copolymer, crotonic acid copolymer, maleic acid copolymer, partially esterified maleic acid copolymer, and the like. Similarly, there is an acidic cellulose derivative having a carboxylic acid group in the side chain. In addition, a polymer obtained by adding a cyclic acid anhydride to a polymer having a hydroxyl group is useful.

Among these, a (meth) acrylic resin having a benzyl group or an allyl group and a carboxyl group in the side chain is particularly preferred because of its excellent balance of film strength, sensitivity and developability.

Further, Japanese Patent Publication No. 7-12004, Japanese Patent Publication No.
JP-A-120041, JP-B-7-120042, JP-B-8-12424, JP-A-63-287944, JP-A-63-287947, JP-A-1-271174,
The urethane-based binder polymer containing an acid group described in Japanese Patent Application No. 10-116232 is very excellent in strength, and therefore is advantageous in terms of printing durability and low exposure suitability.

Further, as the water-soluble linear organic polymer, polyvinyl pyrrolidone and polyethylene oxide are useful. In order to increase the strength of the cured film, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, and the like are also useful.

The weight average molecular weight of the polymer used in the present invention is preferably 5,000 or more, more preferably 10,000 to 300,000, and the number average molecular weight is preferably 1,000 or more, more preferably Is in the range of 2000 to 250,000. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1 or more, and more preferably in the range of 1.1 to 10.

These polymers are random polymers,
Any of a block polymer and a graft polymer may be used, but a random polymer is preferable.

The polymer used in the present invention can be synthesized by a conventionally known method. As a solvent used in the synthesis, for example, tetrahydrofuran, ethylene dichloride, cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, diethylene glycol dimethyl ether, 1-methoxy -2-propanol, 1-methoxy-2-propyl acetate, N, N-
Dimethylformamide, N, N-dimethylacetamide, toluene, ethyl acetate, methyl lactate, ethyl lactate,
Dimethyl sulfoxide, water and the like. These solvents are used alone or in combination of two or more. As the radical polymerization initiator used for synthesizing the polymer used in the present invention, known compounds such as an azo initiator and a peroxide initiator can be used.

The binder polymer used in the present invention may be used alone or as a mixture. These polymers are 20 to 95% by weight based on the total solid content of the photosensitive layer coating solution,
Preferably, it is added to the photosensitive layer at a ratio of 30 to 90% by weight. When the addition amount is less than 20% by weight, the strength of the image portion is insufficient when an image is formed. 95% by weight
If the number exceeds, no image is formed. The weight ratio of the radical polymerizable compound having an ethylenically unsaturated double bond and the linear organic polymer is preferably in the range of 1/9 to 7/3.

[Other Components of Photosensitive Layer] In the present invention, various compounds other than these may be further added, if necessary. For example, a dye having a large absorption in the visible light region can be used as a colorant for an image. In particular,
Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black B
Y, oil black BS, oil black T-505
(Orient Chemical Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI4255)
5), methyl violet (CI42535), ethyl violet, rhodamine B (CI145170B),
Malachite green (CI42000), methylene blue (CI52015), etc., and JP-A-62-29324
No. 7 can be mentioned. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, and titanium oxide can be suitably used.

It is preferable to add these colorants since it is easy to distinguish between image areas and non-image areas after image formation. The addition amount is based on the total solid content of the photosensitive layer coating solution.
The ratio is 0.01 to 10% by weight.

Further, in the present invention, a small amount of thermal polymerization inhibitor is used to prevent unnecessary thermal polymerization of a compound having an ethylenically unsaturated double bond which can be radically polymerized during preparation or storage of a photosensitive layer coating solution. It is desirable to add an agent. Hydroquinone, as a suitable thermal polymerization inhibitor,
p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol), 2,2'-methylenebis (4 -Methyl-6-t-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01% to about 5% by weight based on the weight of the whole composition. If necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide may be added to prevent polymerization inhibition by oxygen, and may be unevenly distributed on the surface of the photosensitive layer in a drying process after coating. . The amount of the higher fatty acid derivative to be added is about 0.1% of the total composition.
1% to about 10% by weight is preferred.

The photosensitive layer coating solution of the present invention may contain a nonionic solvent such as described in JP-A-62-251740 and JP-A-3-208514 in order to increase the stability of processing under development conditions. Surfactant, JP-A-59
An amphoteric surfactant as described in JP-A-121044 and JP-A-4-13149 can be added.

Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, monoglyceride stearate, polyoxyethylene nonyl phenyl ether and the like.

Specific examples of the amphoteric surfactant include alkyl di (aminoethyl) glycine, alkyl polyaminoethyl glycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, N-tetradecyl-N , N-betaine type (for example,
(Trade name: Amogen K, manufactured by Dai-ichi Kogyo Co., Ltd.). The proportion of the nonionic surfactant and amphoteric surfactant in the photosensitive layer coating solution is preferably 0.05 to 15% by weight, more preferably 0.1 to 5% by weight.

Further, a plasticizer may be added to the coating solution for the photosensitive layer according to the present invention, if necessary, in order to impart flexibility to the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, and the like are used.

To produce the image-forming material according to the present invention, the above-mentioned components necessary for the photosensitive layer coating solution are usually dissolved in a solvent and coated on a suitable support. What is necessary is just to apply the coating liquid of a coat layer. Examples of the solvent used for the photosensitive layer coating solution include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, and 1-methoxy-2.
-Propyl acetate, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide,
N-dimethylformamide, tetramethylurea, N-
Examples include, but are not limited to, methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. These solvents are used alone or as a mixture. The concentration of the above components (total solids including additives) in the solvent is preferably 1 to 5
0% by weight.

The coating amount (solid content) of the photosensitive layer on the support obtained after coating and drying varies depending on the application, but generally ranges from 0.5 to 5.0 g / m2 for the image forming material.
² is preferred. Various methods can be used as the method of coating, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating. As the coating amount decreases, the apparent sensitivity increases, but the film characteristics of the photosensitive layer that performs the function of image recording deteriorate.

The photosensitive layer coating solution according to the present invention may contain a surfactant for improving coating properties, for example, JP-A-62-17.
No. 0950 can be added. The preferable addition amount is 0.01 to 1% by weight, more preferably 0.05 to 0.5% by weight, based on the solid content of the material of the entire photosensitive layer.

In the negative-type image recording material to which the method of the present invention is applied, the energy of the irradiated infrared laser or the like is converted into heat by the infrared absorbent (A).
(B) The radical generator generates a radical by its heat. By the action of the radical, the radical polymerizable compound (C) and the binder polymer (D) accelerate the polymerization and curing reaction, thereby performing image recording, that is, plate making of the recording material. However, compounds such as water, bases, acids, and oxygen that trap radicals generated during exposure in the photosensitive layer and inhibit the polymerization reaction are suspended in the air. Since these suspended matters inhibit the above-mentioned polymerization reaction due to heat, it is preferable to provide an overcoat layer in the negative image forming material to which the method of the present invention is applied.

[Overcoat layer] The overcoat layer according to the present invention is particularly so long as it is transparent to actinic rays, that is, rays used for image exposure, and has a certain degree of adhesiveness to an adjacent photosensitive layer. There is no limitation, and known ones can be selected and used. Such an overcoat layer is provided in order to inhibit the compound in the photosensitive layer and the compound generated by exposure to actinic light from being affected by the outside air. Therefore, it is preferable that the low molecular compound existing in the air and the low molecular compound generated in the photosensitive layer have low permeability. That is, the overcoat layer is formed of a substance that traps a compound generated during exposure in the photosensitive layer, or a compound such as water, a base, an acid or oxygen that exists in the air that inhibits a reaction that occurs in the photosensitive layer. Any material can be used as long as it can be prevented from being mixed into the photosensitive layer and the overcoat layer in the non-image area can be removed before or during development. That is, a film having low gas permeability or a film is preferable.

Specific examples of the compound forming the overcoat layer include polyvinyl alcohol, polyvinylidene chloride, poly (meth) acrylonitrile, polysulfone, acetylcellulose, polyvinyl chloride, polyvinyl acetate, and ethylene-vinyl alcohol copolymer. Coalescence, polyethylene, polycarbonate, polystyrene, polyethylene, polyamide, cellophane, acrylic resin, gelatin,
Gum arabic and the like. These can be used alone or
You may use together. More preferably, water-soluble polymers such as polyvinyl alcohol, water-soluble acrylic resin, polyvinylpyrrolidone, gelatin, and gum arabic can be mentioned from the viewpoint of ease of removal during development and ease of coating.
Still more preferably, polyvinyl alcohol, which can be coated with water as a solvent and can be removed with an aqueous developer,
Polyvinylpyrrolidone, gelatin, and gum arabic are preferred, and in order to improve their removability, these water-soluble polymers include a nitrogen-containing water-soluble polymer having a partial structure such as an amine, and a water-soluble polymer having an acid group such as sulfonic acid. You may use together.

The polyvinyl alcohol used in the overcoat layer of the present invention can be partially substituted with an ester, ether or acetal as long as it contains a substantial amount of unsubstituted vinyl alcohol units having the required water solubility. May be. In addition, similarly, a part thereof may contain another copolymerization component. As specific examples of polyvinyl alcohol,
71-100% hydrolyzed, polymerization degree 300-240
And those in the range of 0. Specifically, Kuraray Co., Ltd., PVA-105, PVA-110, PVA-11
7, PVA-117H, PVA-120, PVA-12
4, PVA-124H, PVA-CS, PVA-CS
T, PVA-HC, PVA-203, PVA-204,
PVA-205, PVA-210, PVA-217, P
VA-220, PVA-224, PVA-217EE,
PVA-220, PVA-224, PVA-217E
E, PVA-217E, PVA-220E, PVA-2
24, PVA-405, PVA-420, PVA-61
3, L-8 and the like. As the above copolymer,
88-100% hydrolyzed polyvinyl acetate chloroacetate or propionate, polybierformal and polybieracetal and copolymers thereof. Other useful polymers include polyvinylpyrrolidone, gelatin and gum arabic, which may be used alone or in combination.

The solvent used for applying the overcoat layer is preferably pure water, but alcohols such as methanol and ethanol, and ketones such as acetone and methyl ethyl ketone may be mixed with the pure water. The concentration of the solid content in the coating solution is suitably from 1 to 20% by weight.

The overcoat layer may further contain known additives such as a surfactant for improving coating properties and a water-soluble plasticizer for improving physical properties of the film. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, and sorbitol. Further, a water-soluble (meth) acrylic polymer or the like may be added.

The amount of the coating is about 0.1 / m 2 after drying.
A range from ² to about 15 / m ² is suitable. More preferably, it is 1.0 / m ² to about 5.0 / m ² .

[Support] The negative image-forming material according to the method of the present invention is formed by applying the photosensitive layer on a support. The support that can be used here is not particularly limited as long as it is a dimensionally stable plate-like material. For example, paper, plastic (eg, polyethylene, polypropylene, polystyrene, etc.) laminated paper, metal plate ( For example, aluminum, zinc, copper, etc.), plastic film (for example, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate,
Examples thereof include cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or vapor-deposited. Preferred supports include a polyester film or an aluminum plate.

As the support used in the image forming material of the present invention, it is preferable to use an aluminum plate which is lightweight and has excellent surface treatment properties, workability and corrosion resistance. Aluminum materials used for this purpose include JIS 1050
Material, JIS 1100 material, JIS 1070 material, Al-
Mg-based alloy, Al-Mn-based alloy, Al-Mn-Mg-based alloy, Al-Zr-based alloy. Al-Mg-Si alloys and the like can be mentioned.

Suitable aluminum plates are a pure aluminum plate and the above-mentioned alloy plates containing aluminum as a main component and a trace amount of a different element, and may be a plastic film on which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy include silicon,
There are iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel and titanium. The content of the foreign element in the alloy is 10% by weight or less. As the aluminum plate, pure aluminum is preferable. However, since pure aluminum is difficult to produce due to refining technology, it may contain a slightly different element. As described above, the composition of the aluminum plate is not specified, and an aluminum plate of a conventionally known and used material can be appropriately used. The thickness of the aluminum plate is preferably about 0.1 to 0.6 mm, and 0.15 to 0.4 mm.
mm is more preferable, and 0.2 to 0.3 mm is particularly preferable.

Prior to roughening the aluminum plate, if necessary, a degreasing treatment with a surfactant, an organic solvent or an alkaline aqueous solution is performed to remove rolling oil on the surface. The surface roughening treatment of the surface of the aluminum plate is performed by various methods, for example, a method of mechanically roughening the surface, a method of electrochemically dissolving the surface, and a method of selectively dissolving the surface chemically. It is performed by the method of causing. Known mechanical methods such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method can be used as the mechanical method. Further, as an electrochemical surface roughening method, there is a method of performing an alternating or direct current in a hydrochloric acid or nitric acid electrolyte.

The aluminum plate thus roughened is
Alkaline etching treatment and neutralization treatment as necessary
After removal, if necessary, the water retention and abrasion resistance of the surface can be increased.
Anodizing treatment is performed for the purpose. Anodizing, by anodizing
1.0 g / m ^TwoThe above is preferred. Anodic acid
1.0 g / m^TwoIf less than, press life
Is insufficient or used as a lithographic printing plate
Indicates that the non-image area is easily scratched and
So-called "scratch stain" that ink adheres to the surface
Sometimes. After being subjected to the anodizing treatment,
The surface of the minium is subjected to a hydrophilic treatment if necessary.
You.

Further, such an aluminum support is treated with an organic acid or a salt thereof after anodizing treatment, or
An undercoat layer applied to a photosensitive layer can be applied for use.

An intermediate layer for improving the adhesion between the support and the photosensitive layer may be provided. To improve adhesion,
Generally, the intermediate layer is made of a diazo resin or a phosphoric acid compound adsorbed on aluminum, for example. The thickness of the intermediate layer is arbitrary, and must be such a thickness that a uniform bond-forming reaction with the upper photosensitive layer can be performed when exposed. Normal,
The dry solid has a good coating ratio of about 1 to 100 mg / m ² ,
5-40 mg / m ² are particularly good. The usage ratio of the diazo resin in the intermediate layer is 30 to 100%, preferably 60 to 100%.

After the above-described treatment or undercoating is applied to the surface of the support, a back coat is provided on the back surface of the support, if necessary. As such a back coat, a coating layer comprising a metal oxide obtained by hydrolysis and polycondensation of an organic polymer compound described in JP-A-5-45885 and an organic or inorganic metal compound described in JP-A-6-35174 is used. It is preferably used.

The preferred characteristics of the lithographic printing plate support are center line average roughness of 0.10 to 1.2 μm. If it is less than 0.10 μm, the adhesion to the photosensitive layer is reduced,
Significant reduction in printing durability occurs. If it is larger than 1.2 μm, the stain on printing will be deteriorated. Further, the color density of the support is 0.15 to 0.5 as a reflection density value.
65, and when it is whiter than 0.15, the halation at the time of image exposure is too strong and hinders image formation.
When it is darker than 0.65, the image is difficult to see in the plate inspection work after development, and the plate inspection property is extremely poor.

As described above, on the support obtained by performing a predetermined treatment, the above-mentioned photosensitive layer and any other optional layers such as a surface protective layer and a back coat layer are formed. Thus, a negative image forming material to which the method of the present invention can be applied can be obtained. In the method of the present invention, an image is recorded on this image forming material with an infrared laser. Also, thermal recording with an ultraviolet lamp or a thermal head is possible. In the present invention, it is preferable that the image is exposed by a solid-state laser or a semiconductor laser that emits infrared rays having a wavelength of 760 nm to 1200 nm. Laser output is 100mW
The above is preferable, and in order to shorten the exposure time, it is preferable to use a multi-beam laser device. Further, the exposure time per pixel is preferably within 20 μsec. The energy applied to the recording material is 10 to 300 m
It is preferably J / cm ² .

After the image forming material is exposed to infrared laser, it is developed with a developing solution, preferably a weakly alkaline aqueous solution described in detail above, to obtain a lithographic printing plate.

The image-forming material which has been developed using the developing solution and the replenisher described above may be, if desired, a washing solution, a rinsing solution containing a surfactant or the like, or a desensitizing solution containing gum arabic or a starch derivative. After post-processing, it is used as a lithographic printing plate.

In recent years, in the plate making / printing industry, automatic developing machines for printing plate materials have been widely used in order to rationalize and standardize plate making operations. This automatic developing machine generally includes a developing section and a post-processing section, and includes a device for transporting a printing plate material, each processing solution tank, and a spray device. The developing process is performed by spraying each pumped processing liquid from a spray nozzle. Recently, a method is also known in which a printing plate material is immersed and conveyed by a submerged guide roll or the like into a processing liquid tank filled with a processing liquid to perform processing. In such automatic processing,
Processing can be performed while replenishing each processing solution with a replenisher according to the processing amount, operating time, and the like. In addition, the electric conductivity can be detected by a sensor and replenished automatically. Further, a so-called disposable processing method in which processing is performed with a substantially unused processing liquid can also be applied.

The lithographic printing plate obtained as described above can be subjected to a printing step after applying a desensitized gum if desired, but when it is desired to obtain a lithographic printing plate having higher printing durability. Is subjected to a burning process.

In the case of burning a lithographic printing plate, prior to burning, Japanese Patent Publication Nos. 61-2518 and 55-280.
No. 62, JP-A-62-131859 and JP-A-61-1596.
It is preferable to treat with a surface-regulating liquid as described in each of the publications No. 55.

[0153] As a method for this, a sponge or absorbent cotton impregnated with the surface conditioning liquid is applied onto a lithographic printing plate,
A method in which a printing plate is immersed in a vat filled with a surface conditioning liquid to apply the printing plate, an application using an automatic coater, or the like is applied. Further, it is preferable to make the application amount uniform with a squeegee or a squeegee roller after the application. The application amount of the surface conditioning liquid is generally 0.03 to 0.8 g / m ^2.
(Dry weight) is appropriate.

The lithographic printing plate to which the surface conditioning liquid has been applied is dried if necessary, and then burned with a burning processor (for example,
It is heated to a high temperature by a burning processor (BP-1300) sold by Fuji Photo Film Co., Ltd. The heating temperature and time in this case depend on the type of the component forming the image, but may be 1 to 180 ° C. to 300 ° C.
A range of up to 20 minutes is preferred.

The burned lithographic printing plate can be subjected to a conventional treatment such as washing with water or gumming if necessary. However, a surface conditioning solution containing a water-soluble polymer compound or the like can be used. When is used, so-called desensitizing treatment such as gumming can be omitted.

The lithographic printing plate obtained by the image forming method of the present invention is applied to an offset printing machine or the like and used for printing a large number of sheets.

[0157]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited to these examples. (Target Example 1) [Preparation of Support] 99.5% or more of aluminum and F
e 0.30%, Si 0.10%, Ti 0.02%, C
u A molten metal of JIS A1050 alloy containing 0.013% was subjected to cleaning treatment and cast. In the cleaning treatment, a degassing treatment was performed to remove unnecessary gases such as hydrogen in the molten metal, and a ceramic tube filter treatment was performed. The casting was performed by DC casting. The solidified ingot having a thickness of 500 mm was chamfered from the surface by 10 mm, and homogenized at 550 ° C. for 10 hours to prevent the intermetallic compound from becoming coarse. Next, after hot rolling at 400 ° C. and intermediate annealing in a continuous annealing furnace at 500 ° C. for 60 seconds, cold rolling was performed to obtain a rolled aluminum sheet having a sheet pressure of 0.30 mm. The center line average surface roughness Ra after cold rolling was controlled to 0.2 μm by controlling the roughness of the rolling roll. Then, it was subjected to a tension leveler to improve the flatness.

Next, a surface treatment for forming a lithographic printing plate support was performed. First, in order to remove the rolling oil on the surface of the aluminum plate, a degreasing treatment was performed with a 10% aqueous sodium aluminate solution at 50 ° C. for 30 seconds, and a 30% sulfuric acid aqueous solution was neutralized at 50 ° C. for 30 seconds and a smut removal treatment was performed.

Next, in order to improve the adhesion between the support and the photosensitive layer and to impart water retention to the non-image area, a so-called graining treatment for roughening the surface of the support was performed. 1%
Aqueous solution containing 0.5% nitric acid and 0.5% aluminum nitrate
° C while flowing an aluminum web in an aqueous solution, the anode-side electricity quantity 240 C / dm ² with an alternating waveform having a current density of 20 A / dm ² and a duty ratio of 1: 1 by an indirect feeding cell.
Electrolytic graining was performed by giving ² . Then 10%
Perform an etching treatment with a sodium aluminate aqueous solution at 50 ° C for 30 seconds, and neutralize with a 30% aqueous sulfuric acid solution at 50 ° C for 30 seconds.
Smut removal processing was performed.

In order to further improve abrasion resistance, chemical resistance and water retention, an oxide film was formed on the support by anodic oxidation. An anodic oxide film of 2.5 g / m ^{2 is} obtained by performing an electrolytic treatment with a direct current of 14 A / dm ² by an indirect power supply cell while carrying an aluminum web through the electrolyte using a 20% aqueous solution of sulfuric acid at 35 ° C. as an electrolyte. It was created.

Thereafter, a silicate treatment was performed to ensure hydrophilicity as a non-image portion of the printing plate. For the treatment, a 1.5% aqueous solution of sodium silicate No. 3 was maintained at 70 ° C., passed through the aluminum web so that the contact time was 15 seconds, and further washed with water. S
The attached amount of i was 10 mg / m ² . Ra (center line surface roughness) of the support thus prepared was 0.25 μm.

[Undercoating] Next, the following undercoating solution was applied to this aluminum support with a wire bar, and dried at 90 ° C. for 30 seconds using a hot air drier. The coating amount after drying was 10 mg / m ² .

<Undercoat liquid> 0.1 g of a copolymer of ethyl methacrylate and 2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt in a molar ratio of 75:15 0.1 g 2-aminoethylphosphonic acid 0.1 g 50 g of methanol 50 g of ion exchange water

[Photosensitive layer] Next, the following photosensitive layer coating solution [P]
Is applied to the undercoated aluminum plate using a wire bar, and dried at 115 ° C. for 45 seconds with a hot air drier to form a photosensitive layer, and a negative type lithographic printing plate precursor [P- 1] to obtain Example 1. The coating amount after drying was in the range of 1.2 to 1.3 g / m ^2.

<Coating solution for photosensitive layer [P]> • Infrared absorber [IR-6] 0.08 g • Onium salt [OI-6] 0.30 g • Dipentaerythritol hexaacrylate 1.00 g • Allyl methacrylate and methacrylic acid Copolymer having a molar ratio of 80:20 (weight average molecular weight 120,000) 1.00 g-Victoria pure blue naphthalene sulfonate 0.04 g-Fluorosurfactant 0.01 g (MegaFac F-176, Dainippon Japan)・ Methyl ethyl ketone 9.0g ・ Methanol 10.0g ・ 1-Methoxy-2-propanol 8.0g

[0166]

Embedded image

[Exposure] The obtained negative type lithographic printing plate precursor [P-1] was used as a Trendsetter 3244VF manufactured by Creo Corporation equipped with a water-cooled 40 W infrared semiconductor laser.
At S, the output is 9 W, the rotation speed of the outer drum is 210 rpm, the plate surface energy is 100 mJ / cm ² , and the resolution is 2400 dp.
Exposure was performed under the conditions of i.

[Development processing] After exposure, development processing was performed using an automatic developing machine Stublon 900N manufactured by Fuji Photo Film Co., Ltd. As a developing solution, a 1: 1 water-diluted solution of DN-3C (pH 10.5 at 25 ° C.) manufactured by Fuji Photo Film Co., Ltd. was used for both the charging solution and the replenishing solution. The temperature of the developing bath was 30 ° C. The finisher used was a 1: 1 water dilution of FN-6 manufactured by Fuji Photo Film Co., Ltd.

[Evaluation of Printing Durability and Smear] Next, a lithographic printing plate [P-1] was printed using a printing machine Lithrone manufactured by Komori Corporation. At this time, after the start of printing, it was visually evaluated how many prints sufficiently covered with ink were obtained. Further, the state of the stain on the non-image portion at that time was visually observed. As a result, 48,000 good printed matters were obtained. In addition, no stain was observed on the non-image portion of the obtained printed matter.

Example 1 An image was formed in the same manner as in Example 1 except that the following heating step was performed prior to the developing step after the exposure step, and a lithographic printing plate [P-2 ] Was obtained.

[Heat treatment] A black-coated halogen lamp heater having a diameter of 2.50 mm was used as a heating device, and the exposed negative type lithographic printing plate precursor was heated to 110 ° C.
For 12 seconds.

Next, the lithographic printing plate [P-2] was used as the target example 1.
Printing was performed in the same manner as described above, and printing durability and stain were evaluated. As a result, 80,000 good prints were obtained. Further, no stain was observed on the non-image portion of the obtained printed matter. From this, it can be seen that by performing a mild heat treatment prior to development after image exposure, the printing durability was significantly improved as compared to the target example, and no stain was generated in the non-image area. Was.

[0173]

According to the present invention, recording is performed using a solid-state laser and a semiconductor laser that emit infrared light.
An image which can be applied to a negative type image forming material which can be directly recorded from digital data of a computer or the like and which does not require a large-scale device or energy, and which can provide a lithographic printing plate excellent in image formability and printing durability. A forming method can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic flow of a plate making system to which a method of the present invention is applied.

FIG. 2 is an explanatory diagram showing a schematic configuration of the automatic developing machine shown in FIG.

FIG. 3 is a flowchart illustrating an operation of a CPU of a heating control unit illustrated in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Personal computer 12 Workstation 14 Plate setter 16 Processor 18 Setter control part 20 Heating part 22 Washing part 24 Developing part 26 Washing part 28 Finisher part 29 Drying part 30 Processor control part 32 Heating device 34 Heating means 36 Transport roller 38 Heating control part 110 Negative image forming material

Claims (4)

[Claims] 1. A support, comprising: (A) an infrared absorber;
An exposure step of exposing an image of a negative-type image forming material provided with a photosensitive layer containing (B) a radical generator, (C) a radical polymerizable compound, and (D) a binder polymer with an infrared laser; A heating step of heating the negative image forming material in a temperature range of 60 to 120 ° C. for 1 to 20 seconds; and a developing step of developing the heated negative image forming material with an aqueous alkaline solution. Image forming method. 2. The image forming method according to claim 1, wherein the developing step is a step of developing using a weak alkaline aqueous solution having a pH in a range of 7 to 12. 3. A water washing step in which the negative image forming material has a water-soluble overcoat layer on a photosensitive layer, and the water-soluble overcoat layer is removed by water washing before the developing step. The image forming method according to claim 1, further comprising: 4. The image forming method according to claim 1, wherein heating conditions in the heating step are controlled by plate information of the negative image forming material.