JP5203477B2 - Support for lithographic printing plate and lithographic printing plate precursor - Google Patents

Description

  The present invention relates to a lithographic printing plate support and a lithographic printing plate precursor obtained using the support.

  The lithographic printing method is a printing method that utilizes the fact that water and oil are not essentially mixed. The printing plate surface of the lithographic printing plate used for this is a region that accepts water and repels oil-based ink (hereinafter referred to as “removal”). This region is referred to as a “non-image portion”) and a region that repels water and receives oil-based ink (hereinafter, this region is referred to as “image portion”).

  An aluminum support for a lithographic printing plate used for a lithographic printing plate (hereinafter simply referred to as a “support for a lithographic printing plate”) is used so that its surface bears a non-image portion, and therefore has hydrophilicity and water retention. Are required to have various performances which are contradictory to each other, for example, excellent adhesion, and excellent adhesion to an image recording layer provided thereon. If the hydrophilicity of the support is too low, ink will adhere to the non-image area during printing, and the blanket cylinder will be soiled, and so-called background soiling will occur. On the other hand, if the water holding capacity of the support is too low, the shadow portion is clogged unless dampening water is increased during printing. Therefore, the so-called water width is narrowed.

  Various studies have been made to obtain a lithographic printing plate support having good performance. For example, in Patent Document 1, after the surface of the roughened aluminum plate is anodized as the first stage, the pore diameter is smaller than the micropores of the first stage anodized film as the second stage. A method for producing a lithographic printing plate support by anodizing again is disclosed. The lithographic printing plate obtained by using the lithographic printing plate support is described to improve the adhesion with the photosensitive layer without deteriorating the ink removal, and it has excellent printing durability with no highlights flying. Yes.

  On the other hand, when printing, printing may be temporarily stopped. In this case, the lithographic printing plate is left in a state where it is attached to the plate cylinder, and the non-image area becomes dirty due to the influence of contamination in the atmosphere. For this reason, when printing is paused and resumed, it becomes necessary to print several sheets until normal printing is performed, and there is a disadvantage that printing paper is wasted. This inconvenience has been found to be particularly noticeable in lithographic printing plates that have been electrochemically roughened in an acidic solution containing hydrochloric acid. In the following, the number of damaged paper sheets generated when printing is paused and restarted is evaluated as neglectability, and the fact that the number of damaged sheets is small is referred to as good neglectability.

  In addition, many studies have been conducted on computer-to-plate (CTP) systems that have made remarkable progress in recent years. In particular, there is a need for a lithographic printing plate precursor that can be mounted on a printing machine as it is and printed without being subjected to development processing after exposure, in order to further streamline the process and solve the waste liquid treatment problem.

  One method of eliminating the processing step is to mount the exposed lithographic printing plate precursor on the plate cylinder of the printing press, and supply dampening water and ink while rotating the plate cylinder to remove the lithographic printing plate precursor. There is a method called on-machine development that removes the image area. That is, the lithographic printing plate precursor is exposed to light and mounted on a printing machine as it is, and development processing is completed in a normal printing process. A lithographic printing plate precursor suitable for on-press development has an image recording layer soluble in dampening water or an ink solvent, and is suitable for development on a printing press placed in a bright room. It is necessary to have good light room handling. In the following, the on-machine development on the printing machine in the unexposed area is completed, and the number of printing sheets required until the ink is not transferred to the non-image area is evaluated as on-machine developability. On-machine developability is said to be good when the number of sheets is small.

JP 11-291657 A

  The present inventors have examined various performances of a lithographic printing plate and a lithographic printing original plate obtained using the lithographic printing plate support specifically described in Patent Document 1, and found that It has been found that printing durability, or on-press developability and printing durability are in a trade-off relationship, and the two cannot be compatible and are not always satisfactory in practice. Furthermore, it has been found that the scratch resistance of the lithographic printing plate support needs to be improved.

  Therefore, in view of the above circumstances, the present invention can provide a lithographic printing plate precursor exhibiting excellent neglectability and printing durability when used as a lithographic printing plate, and exhibiting excellent on-press developability. An object of the present invention is to provide a lithographic printing plate support excellent in scratch resistance and a lithographic printing plate precursor.

As a result of intensive studies to achieve the above object, the present inventors have found that the above problems can be solved by controlling the shape of the micropores in the anodized film.
That is, the present invention provides the following (1) to (5).

(1) A lithographic printing plate support comprising an aluminum plate and an aluminum anodized film thereon, and having micropores extending in the depth direction from the surface opposite to the aluminum plate in the anodized film Because
The micropore communicates with a large-diameter hole extending from the surface of the anodized film to a position having a depth of 5 to 60 nm (depth A) and a bottom of the large-diameter hole, and having a depth of 900 to 2000 nm from the communication position. Consists of a dendritic small-diameter hole extending while branching to a position,
The average diameter (large-diameter hole diameter) of the large-diameter hole on the surface of the anodized film is 10 to 100 nm, and the large-diameter hole diameter and the depth A are (depth A / large-diameter hole diameter) = Satisfies the relationship of 0.1 to 4.0,
The average diameter (small diameter hole diameter) at the communication position of the small diameter hole is greater than 0 and less than 20 nm,
A lithographic printing support having a ratio of the large-diameter hole diameter to the small-diameter hole diameter (small-diameter hole diameter / large-diameter hole diameter) of 0.85 or less.

(2) The lithographic printing plate support according to (1), wherein the thickness of the anodized film from the bottom of the small-diameter hole to the surface of the aluminum plate is 3 nm or more.
(3) The lithographic printing plate support according to (1) or (2), wherein the density of the small-diameter holes in the cross section of the anodized film at the communication position is 100 to 3000 / μm ² .

(4) The density (density B) of the small diameter hole in the cross section of the anodized film at the center position in the depth direction of the small diameter hole is the density of the small diameter hole in the cross section of the anodized film at the communication position ( The support for a lithographic printing plate according to any one of (1) to (3), wherein the support is larger than the density A) and the density B is 300 to 9000 / μm ² .
(5) A lithographic printing plate precursor comprising an image recording layer on the lithographic printing plate support according to any one of (1) to (4).

  According to the present invention, it is possible to obtain a lithographic printing plate precursor exhibiting excellent neglectability and printing durability and excellent on-press developability when used as a lithographic printing plate. A support for a printing plate and a planographic printing plate precursor can be provided.

It is a typical sectional view of one embodiment of a lithographic printing plate support of the present invention. It is a typical sectional view of another mode of one embodiment of a lithographic printing plate support of the present invention. It is a typical sectional view of another mode of one embodiment of a lithographic printing plate support of the present invention. It is typical sectional drawing of the board | substrate and anodized film which show the manufacturing method of the support body for lithographic printing plates of this invention in order of a process. It is a graph which shows an example of the alternating waveform current waveform figure used for the electrochemical roughening process in the manufacturing method of the support body for lithographic printing plates of this invention. It is a side view which shows an example of the radial type cell in the electrochemical roughening process using alternating current in the manufacturing method of the support body for lithographic printing plates of this invention. It is a side view which shows the concept of the process of the brush graining used for the mechanical roughening process in preparation of the support body for lithographic printing plates of this invention. It is the schematic of the anodizing apparatus used for the anodizing process in preparation of the support body for lithographic printing plates of this invention.

The lithographic printing plate support of the present invention and the production method thereof will be described below.
The lithographic printing plate support of the present invention comprises an aluminum plate and an anodized film formed thereon, and the micropores in the anodized film have large diameter holes with a large average diameter and a small average diameter. A dendritic small-diameter hole has a shape configured by being connected along the depth direction (the thickness direction of the film). In particular, in the present invention, the depth of the large-diameter hole portion having a large average diameter in the micropore is controlled, and the small-diameter hole portion has a dendritic shape. The relationship between printability and printing durability, or on-press developability and printing durability can be made compatible at a higher level.

FIG. 1 is a schematic cross-sectional view of an embodiment of the lithographic printing plate support of the present invention.
The planographic printing plate support 10 shown in FIG. 1 has a laminated structure in which an aluminum plate 12 and an aluminum anodic oxide film 14 are laminated in this order. The anodized film 14 has a micropore 16 extending from the surface thereof toward the aluminum plate 12, and the micropore 16 includes a large-diameter hole 18 and a dendritic small-diameter hole 20. Here, the term micropore is a commonly used term representing the pore in the anodized film and does not define the size of the pore.
First, the aluminum plate 12 and the anodized film 14 will be described in detail.

<Aluminum plate>
The aluminum plate 12 (aluminum support) used in the present invention is a metal whose main component is aluminum that is dimensionally stable, and is made of aluminum or an aluminum alloy. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, or a plastic film or paper laminated or vapor-deposited with aluminum (alloy) is selected. Furthermore, a composite sheet in which an aluminum sheet is bonded to a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 may be used.

  In the following description, the above-described plate made of aluminum or aluminum alloy is collectively referred to as an aluminum plate 12. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium, etc., and the content of the foreign element in the alloy is 10% by mass or less. In the present invention, a pure aluminum plate is suitable. However, since pure aluminum is difficult to manufacture in terms of smelting technology, it may contain a slightly different element. Thus, the composition of the aluminum plate 12 applied to the present invention is not specified, and conventionally known and used materials such as JIS A 1050, JIS A 1100, JIS A 3103, JIS A 3005, etc. Can be used as appropriate.

  Further, the aluminum plate 12 used in the present invention is usually processed while continuously running in a web shape, the width is about 400 mm to 2000 mm, and the thickness is about 0.1 mm to 0.6 mm. The width and thickness can be changed as appropriate according to the size of the printing press, the size of the printing plate, and the desire of the user.

  The aluminum plate is appropriately subjected to substrate surface treatment described later.

<Anodized film>
The anodized film 14 is an anodized aluminum film that is generally produced on the surface of the aluminum plate 12 by anodizing treatment and that has an extremely fine micropore 16 that is substantially perpendicular to the film surface and is uniformly distributed. Point to. The micropores 16 extend along the thickness direction (aluminum plate 12 side) from the surface of the anodized film opposite to the aluminum plate 12.

The micropores 16 in the anodic oxide film 14 include a large-diameter hole 18 extending from the surface of the anodic oxide film to a depth of 5 to 60 nm (depth A: see FIG. 1), and a bottom of the large-diameter hole 18. A small-diameter hole portion 20 having a dendritic shape extending while branching from a communication position (communication position C: see FIG. 1) to a position having a depth of 900 to 2000 nm.
Below, the large diameter hole part 18 and the small diameter hole part 20 are explained in full detail.

(Large hole)
The average diameter (average opening diameter) of the large-diameter hole 18 on the surface of the anodized film is 10 to 100 nm. Within this range, excellent printing durability and neglectability of the lithographic printing plate obtained using the lithographic printing plate support, and excellent on-board of the lithographic printing plate precursor obtained using the support. Developability is achieved. The average diameter is preferably 10 to 50 nm, more preferably 15 to 50 nm, and more preferably 20 to 50 nm, in that the printing durability of the lithographic printing plate obtained using the lithographic printing plate support is more excellent. More preferably.
When the average diameter is less than 10 nm, a sufficient anchor effect cannot be obtained, and the printing durability of the lithographic printing plate cannot be improved. Further, when the average diameter exceeds 100 nm, the roughened grain is broken, and various performances such as printing durability and neglectability cannot be improved.

The average diameter of the large-diameter hole portion 18 is in the range of 400 × 600 nm ² in the four images obtained by observing the surface of the anodic oxide film 14 with N = 4 FE-SEM at a magnification of 150,000 times. It is the value obtained by measuring the diameter of the micropore (large-diameter hole) and averaging it.
In addition, when the shape of the large-diameter hole 18 on the image is not circular, an equivalent circle diameter is used. The “equivalent circle diameter” is a diameter of the circle when the shape of the opening is assumed to be a circle having the same projected area as the projected area of the opening.

The bottom of the large-diameter hole 18 is located at a depth of 5 to 60 nm (hereinafter also referred to as depth A) from the anodized film surface. That is, the large-diameter hole 18 is a hole extending 5 to 60 nm in the depth direction (the thickness direction of the anodized film) from the anodized film surface. In the point that the lithographic printing plate obtained by using the lithographic printing plate support is more excellent in printing durability, neglectability, and on-press developability of the lithographic printing plate precursor obtained by using the support, The thickness is preferably 10 to 50 nm.
When the depth is less than 5 nm, a sufficient anchor effect cannot be obtained and the printing durability of the lithographic printing plate cannot be improved. When the depth exceeds 60 nm, the neglectability of the lithographic printing plate or the on-press developability of the lithographic printing plate precursor is poor.
In addition, the said depth is the value which took the photograph (150,000 times) of the cross section of the anodic oxide film 14, measured the depth of the 25 or more large diameter hole part, and averaged it.

The relationship between the average diameter (large diameter hole diameter) of the large diameter hole 18 on the surface of the anodic oxide film and the depth A where the bottom is located (depth A / large diameter hole diameter) is 0.1-4. Satisfies the relationship of .0. In the point that the printing durability of the lithographic printing plate obtained by using the lithographic printing plate support, the neglectability, and the on-press developability of the lithographic printing plate precursor obtained by using the support are ( Depth A / average diameter) is preferably 0.3 or more and less than 3.0, and more preferably 0.3 or more and less than 2.5.
When (depth A / large diameter hole portion diameter) is less than 0.1, the printing durability of the lithographic printing plate cannot be improved. When (depth A / large diameter hole diameter) exceeds 4.0, the neglectability of the lithographic printing plate and the on-press developability of the lithographic printing plate precursor are inferior.

  The shape of the large-diameter hole portion 18 is not particularly limited, and is substantially straight tubular (substantially cylindrical), an inverted conical shape (tapered shape) whose diameter decreases from the anodized film surface toward the aluminum plate 12 side, an anodized film Examples include a substantially conical shape (reverse taper shape) whose diameter increases from the surface toward the aluminum plate 12 side. Preferably, it is a substantially straight tube shape or a reverse taper shape.

  When the large-diameter hole 18 is substantially straight, the inner diameter of the large-diameter hole 18 may have a difference of about 1 to 5 nm as compared with the opening diameter on the surface of the anodized film 16.

FIG. 2 shows a case where the large-diameter hole has a substantially conical shape (reverse taper shape) in which the diameter increases from the anodized film surface toward the aluminum plate 12 side.
The diameter (inner diameter) of the large-diameter hole 18a in the lithographic printing plate support 10a gradually increases from the anodized film surface toward the aluminum plate side. The shape of the large-diameter portion 18a is not particularly limited as long as the diameter condition is satisfied, but is substantially conical or bell-shaped. When the large-diameter hole has the above structure, the lithographic printing plate is excellent in various properties such as printing durability, neglectability, and ink repellency.

  The difference between the average diameter (surface layer average diameter) of the large-diameter hole portion 18a on the surface of the anodized film and the average diameter (bottom portion average diameter) at the communication position C between the small-diameter hole portion 20 is preferably 1 nm or more. Within such a range, the lithographic printing plate has excellent properties such as printing durability, neglectability, and ink repellency. Especially, it is preferable that it is 1 nm or more at the point which printing durability is more excellent, and it is more preferable that it is 10-30 nm.

  The shape of the bottom of the large-diameter hole 18 is not particularly limited, and may be a curved surface (convex shape) or a flat shape.

(Small hole)
As shown in FIG. 1, the small-diameter hole portion 20 is a dendritic hole portion that communicates with the bottom portion of the large-diameter hole portion 18 and branches further from the communication position C in the depth direction (thickness direction). One small-diameter hole 20 usually communicates with one large-diameter hole 18, but two or more small-diameter holes 20 may communicate with the bottom of one large-diameter hole 18.
The average diameter (small-diameter hole diameter) at the communication position C of the small-diameter hole 20 is greater than 0 and less than 20 nm. In terms of neglectability and on-press developability, the average diameter is preferably 15 nm or less, more preferably 13 nm or less, and particularly preferably 5 to 10 nm.
When the average diameter is 20 nm or more, the neglectability of the lithographic printing plate using the lithographic printing plate support of the present invention and the on-press developability of the lithographic printing plate precursor are poor.

The average diameter of the small-diameter hole 20 is such that the surface of the anodic oxide film 14 is observed with N = 4 FE-SEMs with a magnification of 150,000 times, and the obtained four images have a microscopic range of 400 × 600 nm ^2. It is the value obtained by measuring the diameter of the pore (small-diameter hole) and averaging it. When the depth of the large-diameter hole is deep, the upper part of the anodic oxide film 14 (region having the large-diameter hole) is cut (for example, cut with argon gas) as necessary, and then the anodic oxide film 14 is cut. The surface may be observed with the FE-SEM to determine the average diameter of the small diameter holes.
Note that when the shape of the small-diameter hole 20 is not circular on the image, the equivalent circle diameter is used. The “equivalent circle diameter” is a diameter of the circle when the shape of the opening is assumed to be a circle having the same projected area as the projected area of the opening.

The bottom of the small-diameter hole 20 is located at a location extending 900 to 2000 nm further in the depth direction from the communication position C with the large-diameter hole 18. In other words, the small-diameter hole 20 is a hole extending further in the depth direction (thickness direction) from the communication position with the large-diameter hole 18, and the depth of the small-diameter hole 20 is 900 to 2000 nm. From the viewpoint of better scratch resistance of the lithographic printing plate support, the bottom is preferably located at a location extending 900 to 1500 nm from the communication position C.
When the depth is less than 900 nm, the scratch resistance of the lithographic printing plate support is poor. When the depth exceeds 2000 nm, the treatment time is prolonged, and the productivity and economy are inferior.
In addition, the said depth is the value which took the photograph (50,000 times) of the cross section of the anodic oxide film 14, measured the depth of 25 or more small diameter hole parts, and averaged it.

Ratio of the average diameter (small-diameter hole diameter) at the communicating position of the small-diameter hole 20 and the average diameter (large-diameter hole diameter) of the large-diameter hole 18 on the surface of the anodized film (small-diameter hole diameter / large-diameter hole) (Diameter) is 0.85 or less. The lower limit of the ratio is more than 0, preferably 0.02 to 0.85, and more preferably 0.1 to 0.70. Within the above range, the lithographic printing plate is more excellent in printing durability, neglectability and on-press developability of the lithographic printing plate precursor.
When the ratio of the average diameters exceeds 0.85, it is impossible to achieve both printing durability and neglectability / on-press developability.

  As shown in FIG. 1, the shape of the small-diameter hole portion 20 is a branched shape (dendritic shape) along the depth direction (the thickness direction of the anodized film 14). In other words, the small diameter hole portion 20 has one or a plurality of branch points along the depth direction. When the small-diameter hole portion 20 has such a shape, the photosensitive layer component formed in the upper layer of the anodized film is less likely to penetrate into the micropores. As a result, on-machine developability, stability over time, and the like are improved. More improved.

The number of branch points included in the small-diameter hole 20 is not particularly limited and can be adjusted as appropriate. In FIG. 1, there are three branch points.
In FIG. 1, the small-diameter hole 20 is bifurcated at the branch point, but the number of branch branches is not particularly limited. For example, you may branch into three from a branch point.
The distance between branch points in the depth direction (thickness direction) of the anodized film is not particularly limited and can be adjusted as appropriate.

  The size of the inner diameter of the small-diameter hole portion 20 in the depth direction of the anodized film is not particularly limited, but may be the same size as the diameter at the communication position, or may be smaller or larger than the diameter. Note that the inner diameter of the small-diameter hole 20 may have a difference of about 1 to 5 nm along the thickness direction of the anodized film 16.

The density of the small diameter holes in the cross section of the anodized film 14 at the communication position C is preferably 100 to 3000 / μm ² . Within this range, printing durability and neglectability are further improved. Of these, from the viewpoint of excellent more effective, it is preferable that 300 to 800 pieces / [mu] m ^2.

The small-diameter hole is a hole that branches from the communication position toward the aluminum plate as described above, and the density of the small-diameter hole in the cross section of the anodized film (transverse section) increases as it goes toward the aluminum plate. To do. More specifically, the density (density B) of the small diameter hole in the cross section of the anodized film at the center position in the depth direction of the small diameter hole is the density of the small diameter hole in the cross section of the anodized film at the communication position C. It is larger than (density A), and the density B is preferably 300 to 9000 / μm ² . If it is the said range, on-machine developability and progress stability will be more excellent. Among them, more preferably 500 to 3000 pieces / μm ^2. In addition, the center position in the depth direction of the small diameter hole means a place located in the middle of the entire depth of the small diameter hole (corresponding to the center position P in FIG. 1).

  The thickness of the anodized film from the bottom of the small-diameter hole 20 to the surface of the aluminum plate 12 (corresponding to the thickness X in FIG. 1A) is not particularly limited, but is preferably 20 nm or more. The portion of the anodized film located at the thickness X is sometimes called a barrier layer. When the thickness X is in the above range, the resulting lithographic printing plate is excellent in anti-smudge resistance. Especially, it is preferable that the thickness X is 22 nm or more, and it is preferable that it is 24 nm or more at the point which this effect is more excellent. The upper limit is not particularly limited, but is preferably 35 nm or less from the viewpoints of uniform film formation and formation speed.

(Preferred embodiment of small diameter hole)
As shown in FIG. 3, a preferred embodiment of the small-diameter hole is a small-diameter hole 20a having an enlarged-diameter hole 30 whose diameter is increased at its end. In FIG. 3, a portion constituting the small diameter hole portion 20 a other than the enlarged diameter hole portion 30 is referred to as a main hole portion 32. The small diameter hole portion 20 a is configured by connecting the main hole portion 32 and the large diameter hole portion 30 along the thickness direction of the anodized film 16. When the small-diameter hole has such a configuration, the stencil resistance of the lithographic printing plate obtained using the lithographic printing plate support is more excellent.

The enlarged-diameter hole 30 is located at the end of the small-diameter hole 20a. In other words, it is a hole that communicates with the end of the main hole 32 and extends toward the aluminum plate 12 and has a maximum diameter larger than the maximum value of the inner diameter of the main hole 30. As the shape of the enlarged diameter hole portion 30, for example, a substantially bell-shaped hole portion (reverse tapered hole portion) whose hole diameter (diameter) increases from the end of the main hole portion 30 toward the aluminum plate 12 side. Good.
6 nm or more is preferable and, as for the average value of the largest diameter of the diameter expansion hole part 30, 8-30 nm or more is more preferable.
The average value of the difference between the maximum diameter of the enlarged diameter hole portion 30 and the maximum value of the inner diameter of the main hole portion 30 is preferably 3 nm or more, and more preferably 6 to 25 nm.

  As described above, the main hole portion 32 is a hole portion extending in a dendritic shape along the depth direction (thickness direction) of the anodized film.

  Of the total depth from the communication position C of the small-diameter hole 20a to the bottom of the small-diameter hole 20a, the ratio occupied by the depth of the main hole 32 is usually 40 to 98%. 30 occupies the remainder.

The coating amount of the anodic oxide coating 14 is not particularly limited, but is preferably 2.3 to 5.5 g / m ^{2 and} more preferably 2.3 to 4.0 g / m ^{2 in} that the scratch resistance of the lithographic printing plate support is more excellent. ² is more preferable.

  In addition, an image recording layer described later can be provided on the surface of the above-described lithographic printing plate support so that it can be used as a lithographic printing original plate.

<Method for producing support for lithographic printing plate>
Below, the manufacturing method of the said lithographic printing plate support body is demonstrated. Although the manufacturing method of the support for lithographic printing plates is not specifically limited, The manufacturing method which implements the following processes in order is preferable.
(Roughening treatment step) A step of roughening the aluminum plate (first anodizing step) A step of anodizing the roughened aluminum plate (pore wide treatment step) In the first anodizing step The obtained aluminum plate having an anodized film was brought into contact with an aqueous acid solution or an aqueous alkali solution to increase the diameter of the micropores in the anodized film (second anodizing process step). Step of anodizing aluminum plate (third anodizing step) Step of anodizing aluminum plate obtained in second anodizing step (hydrophilizing step) Aluminum plate obtained in second anodizing step The process of applying a hydrophilic treatment to the above process will be described in detail below. Note that the roughening treatment step, the pore wide treatment step, the third anodizing treatment step, and the hydrophilization treatment step may be omitted if not necessary.
FIG. 4 is a schematic cross-sectional view of the substrate and the anodized film showing the first anodizing step to the third anodizing step in the order of steps.

<Roughening treatment process>
The roughening treatment step is a step of subjecting the surface of the aluminum plate to a roughening treatment including an electrochemical roughening treatment. This step is preferably performed before the first anodizing step described later, but may not be performed as long as the surface of the aluminum plate already has a preferable surface shape.

The surface roughening treatment may be performed only by electrochemical surface roughening treatment, but may be performed by combining electrochemical surface roughening treatment with mechanical surface roughening treatment and / or chemical surface roughening treatment. Also good.
When the mechanical surface roughening treatment and the electrochemical surface roughening treatment are combined, it is preferable to perform the electrochemical surface roughening treatment after the mechanical surface roughening treatment.

  In the present invention, the electrochemical surface roughening treatment is preferably performed in an aqueous solution of nitric acid or hydrochloric acid.

The mechanical surface roughening treatment is generally performed for the purpose of setting the surface of the aluminum plate to a surface roughness _Ra : 0.35 to 1.0 μm.
In the present invention, the conditions for the mechanical surface roughening treatment are not particularly limited, but for example, it can be applied according to the method described in Japanese Patent Publication No. 50-40047. The mechanical surface roughening treatment can be performed by brush grain processing using a pumiston suspension or can be performed by a transfer method.
Further, the chemical surface roughening treatment is not particularly limited, and can be performed according to a known method.

After the mechanical surface roughening treatment, the following chemical etching treatment is preferably performed.
The chemical etching process performed after the mechanical roughening process smoothes the uneven edges of the surface of the aluminum plate, prevents ink from being caught during printing, and improves the stain resistance of the lithographic printing plate At the same time, it is performed to remove unnecessary materials such as abrasive particles remaining on the surface.
As the chemical etching treatment, acid etching or alkali etching is known, but as a method that is particularly excellent in terms of etching efficiency, chemical etching treatment using an alkaline solution (hereinafter also referred to as “alkali etching treatment”). ).

The alkaline agent used in the alkaline solution is not particularly limited, and preferred examples include caustic soda, caustic potash, sodium metasilicate, sodium carbonate, sodium aluminate, and sodium gluconate.
Each alkaline agent may contain aluminum ions. The concentration of the alkaline solution is preferably 0.01% by mass or more, more preferably 3% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less. preferable.
Furthermore, the temperature of the alkaline solution is preferably room temperature or higher, more preferably 30 ° C. or higher, preferably 80 ° C. or lower, and more preferably 75 ° C. or lower.

The etching amount is preferably 0.1 g / m ² or more, more preferably 1 g / m ² or more, more preferably 20 g / m ² or less, and 10 g / m ² or less. Is more preferable.
The treatment time is preferably 2 seconds to 5 minutes corresponding to the etching amount, and more preferably 2 to 10 seconds from the viewpoint of improving productivity.

In the present invention, when an alkali etching treatment is performed after the mechanical surface roughening treatment, a chemical etching treatment (hereinafter referred to as “desmut treatment”) is performed using a low-temperature acidic solution in order to remove products generated by the alkali etching treatment. It is also preferable to apply.
Although the acid used for an acidic solution is not specifically limited, For example, a sulfuric acid, nitric acid, and hydrochloric acid are mentioned. The concentration of the acidic solution is preferably 1 to 50% by mass. Moreover, it is preferable that the temperature of an acidic solution is 20-80 degreeC. When the concentration and temperature of the acidic solution are within this range, the spot-like stain resistance of the lithographic printing plate using the lithographic printing plate support of the present invention is further improved.

  In the present invention, the roughening process is a process of applying an electrochemical roughening process after performing a mechanical roughening process and a chemical etching process as desired. Even when the electrochemical surface roughening treatment is performed without performing the chemical surface roughening treatment, the chemical etching treatment can be performed using an alkaline aqueous solution such as caustic soda before the electrochemical surface roughening treatment. Thereby, impurities existing in the vicinity of the surface of the aluminum plate can be removed.

The electrochemical roughening treatment is suitable for making a lithographic printing plate having excellent printability because it is easy to impart fine irregularities (pits) to the surface of the aluminum plate.
The electrochemical surface roughening treatment is performed using direct current or alternating current in an aqueous solution mainly composed of nitric acid or hydrochloric acid.

  Moreover, it is preferable to perform the following chemical etching process after an electrochemical roughening process. Smut and intermetallic compounds exist on the surface of the aluminum plate after the electrochemical roughening treatment. In the chemical etching process performed after the electrochemical surface roughening process, it is preferable to first perform a chemical etching process (alkali etching process) using an alkaline solution in order to efficiently remove smut. Regarding various conditions of the chemical etching treatment using an alkaline solution, the treatment temperature is preferably 20 to 80 ° C., and the treatment time is preferably 1 to 60 seconds. Moreover, it is preferable to contain aluminum ion in an alkaline solution.

Furthermore, after the electrochemical surface roughening treatment, a chemical etching treatment using an alkaline solution is performed, and then a chemical etching treatment (desmut treatment) is performed using a low-temperature acidic solution in order to remove the resulting products. Is preferred.
Even when the alkali etching treatment is not performed after the electrochemical surface roughening treatment, it is preferable to perform a desmut treatment in order to efficiently remove the smut.

  In the present invention, any of the above-described chemical etching treatments can be performed by a dipping method, a shower method, a coating method, or the like, and is not particularly limited.

<First anodizing process>
In the first anodizing treatment step, the aluminum plate having the micropores extending in the depth direction (thickness direction) is formed on the surface of the aluminum plate by anodizing the aluminum plate subjected to the roughening treatment. This is a step of forming a film. By this first anodic oxidation treatment, an aluminum anodic oxide film 14a having micropores 16a is formed on the surface of the aluminum plate 12, as shown in FIG. 4A.

The first anodizing treatment can be performed by a method conventionally performed in this field, but manufacturing conditions are appropriately set so that the above-described micropore 16 can be finally formed.
Specifically, the average diameter (average opening diameter) of the micropores 16a formed in the first anodizing treatment step is usually about 5 to 40 nm, and preferably 7 to 20 nm. If it is in the said range, the micropore 16 which has the predetermined shape mentioned above will be easy to form, and the performance of the obtained lithographic printing plate and lithographic printing plate precursor will be more excellent.
Further, the depth of the micropore 16a is usually about 10 nm or more and less than 100 nm, and preferably 20 to 60 nm. If it is in the said range, the micropore 16 which has the predetermined shape mentioned above will be easy to form, and the performance of the obtained lithographic printing plate and lithographic printing plate precursor will be more excellent.

The pore density of the micropore 16a is not particularly limited, but the pore density is preferably 50 to 4000 / μm ² , and more preferably 100 to 3000 / μm ² . Within the above range, the resulting lithographic printing plate is excellent in printing durability and neglectability and on-press developability of the lithographic printing plate precursor.

Moreover, 35-120 nm is preferable and, as for the film thickness of the anodic oxide film obtained by a 1st anodizing process process, More preferably, it is 40-90 nm. Within the above range, the lithographic printing plate using the lithographic printing plate support obtained through this step is excellent in printing durability and neglectability, and on-press developability of the lithographic printing plate precursor.
Furthermore, the film amount of the anodized film obtained by the first anodizing treatment step is preferably 0.1 to 0.3 g / m ² , more preferably 0.12 to 0.25 g / m ² . Within the above range, the lithographic printing plate using the lithographic printing plate support obtained through this step is excellent in printing durability and neglectability, and on-press developability of the lithographic printing plate precursor.

In the first anodizing treatment step, an aqueous solution of sulfuric acid, phosphoric acid, oxalic acid or the like can be mainly used as an electrolytic bath. Depending on the case, chromic acid, sulfamic acid, benzenesulfonic acid, etc., or an aqueous solution or a non-aqueous solution combining two or more of these may be used. When direct current or alternating current is passed through the aluminum plate in the electrolytic bath as described above, an anodized film can be formed on the surface of the aluminum plate.
The electrolytic bath may contain aluminum ions. Although content of aluminum ion is not specifically limited, 1-10 g / L is preferable.

The conditions for anodizing treatment are appropriately set depending on the electrolytic solution used. In general, the concentration of the electrolytic solution is 1 to 80% by mass (preferably 5 to 20% by mass), and the liquid temperature is 5 to 70 ° C. ( Preferably 10 to 60 ° C., current density 0.5 to 60 A / dm ² (preferably 5 to 50 A / dm ² ), voltage 1 to 100 V (preferably 5 to 50 V), electrolysis time 1 to 100 seconds (preferably The range of 5 to 60 seconds is appropriate.

  Among these anodizing treatments, the method of anodizing at a high current density in sulfuric acid described in British Patent 1,412,768 is particularly preferable.

<Pore wide processing process>
The pore wide treatment step is a treatment (pore diameter enlargement treatment) for enlarging the diameter (pore diameter) of the micropores present in the anodized film formed by the first anodizing treatment step described above. By this pore wide processing, as shown in FIG. 4B, the diameter of the micropore 16a is enlarged, and an anodized film 14b having the micropore 16b having a larger average diameter is formed.
By this pore wide processing, the average diameter of the micropores 16b is expanded to a range of 10 to 100 nm. The micropore 16b is a portion corresponding to the large-diameter hole 18 described above.
Moreover, it is preferable to adjust so that the depth from the surface of the micropore 16b may become comparable with the depth A mentioned above by this process.

  The pore-wide treatment is performed by bringing the aluminum plate obtained by the above-described first anodizing treatment step into contact with an acid aqueous solution or an alkali aqueous solution. The method of making it contact is not specifically limited, For example, the immersion method and the spray method are mentioned. Of these, the dipping method is preferred.

When an alkaline aqueous solution is used in the pore wide treatment step, it is preferable to use at least one alkaline aqueous solution selected from the group consisting of sodium hydroxide, potassium hydroxide, and lithium hydroxide. The concentration of the alkaline aqueous solution is preferably 0.1 to 5% by mass.
After adjusting the pH of the alkaline aqueous solution to 11 to 13, the aluminum plate is placed in the alkaline aqueous solution for 1 to 300 seconds (preferably 1 to 50 seconds) under conditions of 10 to 70 ° C. (preferably 20 to 50 ° C.). It is appropriate to make it contact.
At this time, the alkali treatment liquid may contain a metal salt of a polyvalent weak acid such as carbonate, borate or phosphate.

When an aqueous acid solution is used in the pore-wide treatment step, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, or a mixture thereof. The concentration of the acid aqueous solution is preferably 1 to 80% by mass, more preferably 5 to 50% by mass.
In addition, it is appropriate that the aluminum plate is brought into contact with the acid aqueous solution for 1 to 300 seconds (preferably 1 to 150 seconds) under the condition of the liquid temperature of the acid aqueous solution of 5 to 70 ° C. (preferably 10 to 60 ° C.).
The alkaline aqueous solution or the acidic aqueous solution may contain aluminum ions. Although content of aluminum ion is not specifically limited, 1-10 g / L is preferable.

<Second anodizing process>
The second anodizing treatment step is a step of forming micropores extending in the depth direction (thickness direction) by subjecting the aluminum plate subjected to the above-described pore wide treatment to anodizing treatment. By this second anodizing treatment step, as shown in FIG. 4C, an anodized film 14c having micropores 16c extending in the depth direction is formed.
By this second anodizing treatment step, the average diameter is communicated with the bottom of the micropore 16b, and the average diameter at the communication position is smaller than the average diameter of the micropore 16b (corresponding to the large-diameter hole 18). A new dendritic hole is formed that extends while branching in the depth direction. The hole corresponds to the small diameter hole 20 described above.

  In the second anodizing treatment step, treatment is performed so that the average diameter of newly formed holes is greater than 0 and less than 20 nm, and the depth from the communication position with the large-diameter hole 20 is within the predetermined range described above. Is implemented. In addition, the electrolytic bath used for a process is suitably set as a process condition according to the material used, and what was illustrated by said 1st anodizing process process can be used.

A well-known material can be used for the electrolyte solution etc. which are used at a 2nd anodizing treatment process.
The conditions of the second anodizing treatment step are not particularly limited as long as the dendritic hole is formed. For example, there is a method of performing the treatment while gradually decreasing the current density. In the process, the scanning waveform shows a simple decreasing pattern. The initial current density at that time varies depending on the type of electrolyte used, but is often about 10 to 30 A / dm ² .
Further, the degree of gradual decrease of the current density is not particularly limited, but the current density is from about 25 to 95% (preferably about 30 to 60%) of the initial current density from the point that the branching points of the small-diameter holes are increased. Is preferably gradually reduced.
The scanning time varies depending on the type of electrolyte used, but is preferably about 0.1 to 30 seconds.

The film thickness of the anodized film obtained by the second anodizing treatment step is usually 900 to 2000 nm, preferably 900 to 1500 nm. Within the above range, the lithographic printing plate using the lithographic printing plate support obtained through this step is excellent in printing durability and neglectability, and on-press developability of the lithographic printing plate precursor.
Moreover, the film amount of the anodized film obtained by the second anodizing treatment step is usually 2.2 to 5.4 g / m ² , preferably 2.2 to 4.0 g / m ² . Within the above range, the lithographic printing plate using the lithographic printing plate support obtained through this step is excellent in printing durability and neglectability, and on-press developability of the lithographic printing plate precursor.

  Ratio (film thickness 1 / film thickness) of the thickness of the anodized film obtained by the first anodizing process (film thickness 1) and the thickness of the anodized film obtained by the second anodizing process (film thickness 2) 2) is preferably from 0.01 to 0.15, more preferably from 0.02 to 0.10. Within the above range, the lithographic printing plate support is excellent in scratch resistance.

Further, in order to manufacture the shape of the small-diameter hole 20a described above, the applied voltage may be increased stepwise or continuously immediately before the end of the second anodizing process, or the temperature of the electrolytic solution may be increased. It may be lowered. By performing this treatment, the diameter of the formed hole is increased, and as a result, a shape like the small diameter hole 20a described above is obtained.
Note that, by increasing the voltage applied in the second anodizing treatment step, the thickness of the anodized film between the bottom of the obtained small diameter hole and the aluminum plate tends to increase. If the anodized film between the bottom of the small-diameter hole and the aluminum plate has a predetermined thickness by performing the above-described treatment, the third anodizing treatment step described later may not be performed. .

<Third anodizing process>
In the third anodizing step, the anodizing treatment is mainly performed between the bottom of the small-diameter hole and the aluminum plate by further anodizing the aluminum plate subjected to the second anodizing treatment. This is a step of increasing the thickness of the coating (the thickness of the barrier layer). By this third anodizing treatment step, the thickness X becomes a predetermined size as shown in FIG.
As described above, in the second anodizing process, when the micropores having a desired shape have already been obtained, the third anodizing process need not be performed.

The conditions for the anodizing treatment in the third anodizing treatment step are set as appropriate depending on the electrolyte used. Usually, the treatment is performed at a voltage higher than the voltage applied in the second anodizing treatment step, or the second The process using the electrolyte solution which shows a temperature lower than the electrolyte solution used in the anodizing treatment step is performed.
.
Moreover, the kind of electrolyte solution used is not specifically limited, The electrolyte solution mentioned above can be used. For example, by using an aqueous solution containing boric acid as an electrolytic bath, the thickness X can be efficiently increased without changing the shape of the small-diameter hole portion obtained by the second anodizing treatment.

Moreover, the film amount of the anodized film obtained by the third anodizing treatment step is usually 0.13 to 0.65 g / m ² , preferably 0.26 to 0.52 g / m ² . Within the above range, the printing durability, neglectability, and anti-smudge resistance of the lithographic printing plate using the lithographic printing plate support obtained through this step, and the lithographic printing plate precursor on-machine Excellent developability.

  Note that the micropores may extend further to the aluminum plate side by performing the third anodizing treatment step.

<Hydrophilic treatment process>
The method for producing a lithographic printing plate support of the present invention may have a hydrophilization treatment step in which a hydrophilization treatment is performed after the above-described third anodizing treatment step. As the hydrophilization treatment, a known method disclosed in paragraphs [0109] to [0114] of JP-A-2005-254638 can be used.

  Hydrophilization by a method of immersing in an aqueous solution of an alkali metal silicate such as sodium silicate or potassium silicate, or a method of forming a hydrophilic undercoat layer by applying a hydrophilic vinyl polymer or hydrophilic compound. It is preferable to carry out the treatment.

  Hydrophilization treatment with an aqueous solution of an alkali metal silicate such as sodium silicate and potassium silicate is described in US Pat. No. 2,714,066 and US Pat. No. 3,181,461. It can be performed according to methods and procedures.

  On the other hand, the lithographic printing plate support of the present invention is preferably a lithographic printing plate support obtained by subjecting the above-described aluminum plate to the treatments shown in the following A and B aspects in the order shown below. From the viewpoint of printing durability, the A mode is particularly preferable. In addition, it is desirable to perform water washing between the following processes. However, when two steps (processes) to be performed in succession use a liquid having the same composition, washing with water may be omitted.

(A mode)
(2) Chemical etching treatment in alkaline aqueous solution (first alkali etching treatment)
(3) Chemical etching treatment in acidic aqueous solution (first desmutting treatment)
(4) Electrochemical roughening treatment in an aqueous solution mainly composed of nitric acid (first electrochemical roughening treatment)
(5) Chemical etching treatment in an aqueous alkali solution (second alkali etching treatment)
(6) Chemical etching treatment in acidic aqueous solution (second desmut treatment)
(7) Electrochemical roughening treatment in an aqueous solution mainly composed of hydrochloric acid (second electrochemical roughening treatment)
(8) Chemical etching treatment in an alkaline aqueous solution (third alkali etching treatment)
(9) Chemical etching treatment in acidic aqueous solution (third desmut treatment)
(10) Anodizing treatment (first anodizing treatment, pore wide treatment, second anodizing treatment, third anodizing treatment)
(11) Hydrophilization treatment

(B mode)
(2) Chemical etching treatment in alkaline aqueous solution (first alkali etching treatment)
(3) Chemical etching treatment in acidic aqueous solution (first desmutting treatment)
(12) Electrochemical roughening treatment in an aqueous solution mainly composed of hydrochloric acid (5) Chemical etching treatment in an aqueous alkali solution (second alkali etching treatment)
(6) Chemical etching treatment in acidic aqueous solution (second desmut treatment)
(10) Anodizing treatment (first anodizing treatment, pore wide treatment, second anodizing treatment, third anodizing treatment)
(11) Hydrophilization treatment

In addition, you may implement a mechanical surface roughening process as needed before the process of (2) of the said A aspect and B aspect. From the viewpoint of printing durability and the like, it is preferable that the process (1) is not included in each embodiment.
Here, the mechanical surface roughening treatment, electrochemical surface roughening treatment, chemical etching treatment, anodizing treatment and hydrophilization treatment in the above (1) to (12) are the same as the above-described treatment methods and conditions. However, the treatment is preferably performed under the treatment method and conditions described below.

The mechanical roughening treatment is preferably mechanically roughened with a rotating nylon brush roll having a bristle diameter of 0.2 to 1.61 mm and a slurry liquid supplied to the aluminum plate surface.
Although a well-known thing can be used as an abrasive | polishing agent, quartz sand, quartz, aluminum hydroxide, or a mixture thereof is preferable.
The specific gravity of the slurry liquid is preferably 1.05 to 1.3. Of course, a method of spraying a slurry liquid, a method of using a wire brush, a method of transferring the surface shape of an uneven rolling roll to an aluminum plate, or the like may be used.

The concentration of the alkaline aqueous solution used for the chemical etching treatment in the alkaline aqueous solution is preferably 1 to 30% by mass, and the alloy component contained in aluminum and the aluminum alloy may contain 0 to 10% by mass.
As the alkaline aqueous solution, an aqueous solution mainly composed of caustic soda is particularly preferable. The liquid temperature is preferably from room temperature to 95 ° C., and the treatment is preferably performed for 1 to 120 seconds.
After the etching process is completed, it is preferable to perform liquid draining with a nip roller and water washing with a spray so as not to bring the processing liquid into the next process.

Dissolution amount of the aluminum plate in the first alkali etching treatment is preferably from 0.5 to 30 g / m ^2, more preferably from ^{1.0~20g / m 2, 3.0~15g / m} 2 More preferably.
Dissolution amount of the aluminum plate in the second alkali etching treatment is preferably 0.001~30g / m ^2, more preferably from 0.1-4 g / m ^2, 0.2 to 1.5 g / even more preferably in the range of m ^2.
Dissolution amount of the aluminum plate in the third alkali etching treatment is preferably 0.001~30g / m ^2, more preferably from 0.01~0.8g / m ^2, 0.02~0. More preferably, it is 3 g / m ² .

In chemical etching treatment (first to third desmutting treatment) in an acidic aqueous solution, phosphoric acid, nitric acid, sulfuric acid, chromic acid, hydrochloric acid, or a mixed acid containing two or more acids thereof is preferably used.
The concentration of the acidic aqueous solution is preferably 0.5 to 60% by mass.
Moreover, the alloy component contained in aluminum and aluminum alloy may melt | dissolve 0-5 mass% in acidic aqueous solution.
The liquid temperature is from room temperature to 95 ° C., and the treatment time is preferably 1 to 120 seconds. After the desmut treatment is completed, it is preferable to carry out liquid removal by a nip roller and water washing by spraying in order not to bring the treatment liquid into the next process.

The aqueous solution used for the electrochemical surface roughening treatment will be described.
The aqueous solution mainly composed of nitric acid used in the first electrochemical surface roughening treatment can be one used for an electrochemical surface roughening treatment using ordinary direct current or alternating current, and an aqueous nitric acid solution of 1 to 100 g / L. One or more of hydrochloric acid or nitric acid compound having nitric acid ions such as aluminum nitrate, sodium nitrate and ammonium nitrate; hydrochloric acid ions such as aluminum chloride, sodium chloride and ammonium chloride; be able to.
Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, and a silica, may melt | dissolve in the aqueous solution which has nitric acid as a main component.
Specifically, it is preferable to use a solution in which aluminum chloride and aluminum nitrate are added so that aluminum ions are 3 to 50 g / L in a 0.5 to 2 mass% nitric acid aqueous solution.
The temperature is preferably 10 to 90 ° C, more preferably 40 to 80 ° C.

On the other hand, the aqueous solution mainly composed of hydrochloric acid used in the second electrochemical surface roughening treatment can be one used for an electrochemical surface roughening treatment using normal direct current or alternating current, and has an amount of 1 to 100 g / L. One or more of hydrochloric acid or nitric acid compound having nitric acid ions such as aluminum nitrate, sodium nitrate and ammonium nitrate; hydrochloric acid ions such as aluminum chloride, sodium chloride and ammonium chloride; Can be used.
Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, and a silica, may melt | dissolve in the aqueous solution which has hydrochloric acid as a main component.
Specifically, it is preferable to use a solution in which aluminum chloride and aluminum nitrate are added so that the aluminum ion is 3 to 50 g / L in an aqueous solution of 0.5 to 2% by mass of hydrochloric acid.
Moreover, 10-60 degreeC is preferable and 20-50 degreeC is more preferable. Hypochlorous acid may be added.
On the other hand, the aqueous solution mainly composed of hydrochloric acid used in the electrochemical surface roughening treatment in the aqueous hydrochloric acid solution in the embodiment B can be used for the electrochemical surface roughening treatment using ordinary direct current or alternating current, It can be used by adding 0-30 g / L of sulfuric acid to 1-100 g / L hydrochloric acid aqueous solution. Also, to this solution, one or more of hydrochloric acid or nitric acid compound having nitrate ions such as aluminum nitrate, sodium nitrate, ammonium nitrate; hydrochloric acid ions such as aluminum chloride, sodium chloride, ammonium chloride, etc. are added to 1 g / L to saturation. Can be used.
Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, and a silica, may melt | dissolve in the aqueous solution which has hydrochloric acid as a main component.
Specifically, it is preferable to use a solution obtained by adding aluminum chloride, aluminum nitrate, or the like so that the aluminum ion is 3 to 50 g / L in an aqueous solution of 0.5 to 2% by mass of nitric acid.
Moreover, 10-60 degreeC is preferable and 20-50 degreeC is more preferable. Hypochlorous acid may be added.

  A sine wave, a rectangular wave, a trapezoidal wave, a triangular wave, or the like can be used as the AC power supply waveform for the electrochemical roughening treatment. The frequency is preferably 0.1 to 250 Hz.

FIG. 5 is a graph showing an example of an alternating waveform current waveform diagram used for electrochemical surface roughening treatment in the method for producing a lithographic printing plate support of the present invention.
In FIG. 5, ta is the anode reaction time, tc is the cathode reaction time, tp is the time until the current reaches the peak from 0, Ia is the peak current on the anode cycle side, and Ic is the peak current on the cathode cycle side It is. In the trapezoidal wave, the time tp until the current reaches a peak from 0 is preferably 1 to 10 msec. Due to the influence of the impedance of the power supply circuit, if tp is less than 1, a large power supply voltage is required at the rise of the current waveform, and the equipment cost of the power supply increases. When it is longer than 10 msec, it is easily affected by a trace component in the electrolytic solution, and uniform surface roughening is difficult to be performed. The condition of one cycle of alternating current used for electrochemical surface roughening is that the ratio tc / ta of the anode reaction time ta to the cathode reaction time tc of the aluminum plate is 1 to 20, the quantity of electricity Qc when the aluminum plate is anode and the anode It is preferable that the ratio Qc / Qa of the amount of electricity Qa is 0.3 to 20 and the anode reaction time ta is 5 to 1000 msec. tc / ta is more preferably 2.5 to 15. Qc / Qa is more preferably 2.5 to 15. The current density is preferably a trapezoidal wave peak value of 10 to 200 A / dm ² for both the anode cycle side Ia and the cathode cycle side Ic of the current. Ic / Ia is preferably in the range of 0.3-20. The total amount of electricity furnished to anode reaction of the aluminum plate at the time the electrochemical graining is finished preferably 25~1000C / dm ^2.

  In the present invention, as an electrolytic cell used for electrochemical surface roughening using alternating current, known electrolytic cells such as vertical, flat and radial types can be used. A radial electrolytic cell as described in Japanese Patent No. 195300 is particularly preferred.

The apparatus shown in FIG. 6 can be used for electrochemical surface roughening using alternating current.
FIG. 6 is a side view showing an example of a radial cell in an electrochemical surface roughening treatment using alternating current in the method for producing a lithographic printing plate support of the present invention.
In FIG. 6, 50 is a main electrolytic cell, 51 is an AC power source, 52 is a radial drum roller, 53a and 53b are main electrodes, 54 is an electrolyte supply port, 55 is an electrolyte, 56 is a slit, 57 is an electrolyte passage, 58 is an auxiliary anode, 60 is an auxiliary anode tank, and W is an aluminum plate. When two or more electrolytic cells are used, the electrolysis conditions may be the same or different.
The aluminum plate W is wound around a radial drum roller 52 disposed so as to be immersed in the main electrolytic cell 50, and is subjected to electrolytic treatment by main electrodes 53a and 53b connected to the AC power source 51 in the course of conveyance. The electrolytic solution 55 is supplied from the electrolytic solution supply port 54 to the electrolytic solution passage 57 between the radial drum roller 52 and the main poles 53a and 53b through the slit 56. The aluminum plate W treated in the main electrolytic cell 50 is then subjected to electrolytic treatment in the auxiliary anode cell 60. An auxiliary anode 58 is disposed opposite to the aluminum plate W in the auxiliary anode tank 60, and the electrolytic solution 55 is supplied so as to flow in the space between the auxiliary anode 58 and the aluminum plate W.

  On the other hand, in the electrochemical surface roughening process (first and second electrochemical surface roughening processes), a direct current is applied between the aluminum plate and the electrode facing the aluminum plate to electrochemically roughen the surface. There may be.

<Drying process>
After obtaining the lithographic printing plate support obtained by the steps described above, it is preferable to perform a treatment (drying step) for drying the surface of the lithographic printing plate support before providing an image recording layer described later.
Drying is preferably performed after the final treatment of the surface treatment, after washing with water and draining with a nip roller. Although it does not restrict | limit especially as specific conditions, It is preferable to dry with a hot air (50-200 degreeC) or a cold-air natural drying method.

<Lithographic printing plate precursor>
The lithographic printing plate support of the present invention can be provided with an image recording layer such as a photosensitive layer and a heat-sensitive layer exemplified below to form the lithographic printing plate precursor of the present invention. The image recording layer is not particularly limited. For example, conventional positive type, conventional negative type, photopolymer type, thermal positive type, thermal negative type, described in paragraphs [0042] to [0198] of JP-A-2003-1956, A non-processing type that can be developed on the machine is preferable.
Hereinafter, a suitable image recording layer will be described in detail.

<Image recording layer>
A preferred image recording layer that can be used in the lithographic printing plate precursor according to the present invention is a layer that can be removed by printing ink and / or fountain solution. Specifically, an infrared absorber, a polymerization initiator, An image recording layer having a polymerizable compound and capable of recording by irradiation with infrared rays is preferred.
In the lithographic printing plate precursor of the present invention, the exposed portion of the image recording layer is cured by infrared irradiation to form a hydrophobic (lipophilic) region, and the unexposed portion is dampened with water, ink or ink at the start of printing. It is quickly removed from the support by an emulsion of fountain solution and ink.
Hereinafter, each component of the image recording layer will be described.

(Infrared absorber)
When forming an image of the lithographic printing plate precursor according to the present invention using a laser emitting infrared rays of 760 to 1200 nm as a light source, an infrared absorber is usually used.
The infrared absorber has a function of converting the absorbed infrared ray into heat and a function of being excited by the infrared ray and transferring electrons / energy to a polymerization initiator (radical generator) described later.
The infrared absorbent that can be used in the present invention is a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 nm.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used.
Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned. For example, the dyes disclosed in paragraphs [0096] to [0107] of JP2009-255434A can be suitably used.

  On the other hand, as the pigment, for example, pigments described in paragraphs [0108] to [0112] of JP2009-255434A can be used.

(Polymerization initiator)
The polymerization initiator is a compound that generates radicals by energy of light, heat, or both, and initiates and accelerates polymerization of a compound having a polymerizable unsaturated group. In the present invention, it generates radicals by heat. It is preferable to use a compound (thermal radical generator).
As the polymerization initiator, a known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, a photopolymerization initiator, or the like can be used.
As the polymerization initiator, for example, polymerization initiators described in paragraphs [0115] to [0141] of JP-A-2009-255434 can be used.

  An onium salt or the like can be used as a polymerization initiator, and an oxime ester compound, a diazonium salt, an iodonium salt, or a sulfonium salt is preferable in terms of reactivity and stability.

  These polymerization initiators are added in a proportion of 0.1 to 50% by mass, preferably 0.5 to 30% by mass, particularly preferably 1 to 20% by mass, based on the total solid content constituting the image recording layer. Can do. Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained.

(Polymerizable compound)
The polymerizable compound is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is selected from compounds having at least one, preferably two or more terminal ethylenically unsaturated bonds. In the present invention, those compounds widely known in the technical field of the present invention can be used without any particular limitation.
As the polymerizable compound, for example, polymerizable compounds exemplified in paragraphs [0142] to [0163] of JP-A-2009-255434 can be used.

  Also suitable are urethane-based addition polymerizable compounds produced by the addition reaction of isocyanate and hydroxyl groups. Specific examples thereof include a vinyl monomer containing a hydroxyl group represented by the following general formula (A) in a polyisocyanate compound having two or more isocyanate groups per molecule described in JP-B-48-41708. And vinyl urethane compounds containing two or more polymerizable vinyl groups in one molecule to which is added.

^{_{CH 2 = C (R 4)}} COOCH 2 CH (R 5) OH (A)
(However, R ⁴ and R ⁵ represent H or CH _3. )

  The polymerizable compound is used in an amount of preferably 5 to 80% by mass, more preferably 25 to 75% by mass, based on the nonvolatile component in the image recording layer. These may be used alone or in combination of two or more.

(Binder polymer)
In the present invention, a binder polymer can be used for the image recording layer in order to improve the film forming property of the image recording layer.
Conventionally known binder polymers can be used without limitation, and polymers having film properties are preferred. Specifically, as such a binder polymer, for example, acrylic resin, polyvinyl acetal resin, polyurethane resin, polyurea resin, polyimide resin, polyamide resin, epoxy resin, methacrylic resin, polystyrene resin, novolac phenolic resin, Polyester resin, synthetic rubber, natural rubber and the like can be mentioned.
The binder polymer may have crosslinkability in order to improve the film strength of the image area. In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization.
As the binder polymer, for example, binder polymers disclosed in paragraphs [0165] to [0172] of JP-A-2009-255434 can be used.

The content of the binder polymer is 5 to 90% by mass, preferably 5 to 80% by mass, and more preferably 10 to 70% by mass with respect to the total solid content of the image recording layer. Within this range, good image area strength and image formability can be obtained.
Moreover, it is preferable to use a polymeric compound and a binder polymer in the quantity used as 0.5 / 1-4/1 by mass ratio.

(Surfactant)
In the image recording layer, it is preferable to use a surfactant in order to promote on-press developability at the start of printing and to improve the coated surface state.
Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants.
As the surfactant, for example, surfactants disclosed in paragraphs [0175] to [0179] of JP-A-2009-255434 can be used.

Surfactant can be used individually or in combination of 2 or more types.
The content of the surfactant is preferably 0.001 to 10% by mass and more preferably 0.01 to 5% by mass with respect to the total solid content of the image recording layer.

  In addition to these, various compounds may be added to the image recording layer as necessary. For example, colorants, print-out agents, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic fine particles, low molecular weight hydrophilic compounds and the like disclosed in paragraphs [0181] to [0190] of JP-A-2009-255434 are disclosed. Can be mentioned.

<Formation of image recording layer>
The image recording layer is formed by preparing a coating solution by dispersing or dissolving the necessary components described above in a solvent and then coating the coating solution on a support. Here, as a solvent to be used, ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, Although water etc. can be mentioned, it is not limited to this.
These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.

Further, the coating amount (solid content) of the image recording layer on the lithographic printing plate support obtained after coating and drying varies depending on the use, but is generally preferably 0.3 to 3.0 g / m ² . Within this range, good sensitivity and good film characteristics of the image recording layer can be obtained.
Examples of the coating method include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

<Undercoat layer>
In the lithographic printing plate precursor according to the invention, it is desirable to provide an undercoat layer between the image recording layer and the lithographic printing plate support described above.

The undercoat layer preferably contains a polymer having a substrate adsorptive group, a polymerizable group, and a hydrophilic group.
As the polymer having a substrate adsorptive group, a polymerizable group and a hydrophilic group, a monomer having an adsorptive group, a monomer having a hydrophilic group, and a monomer having a polymerizable reactive group (crosslinkable group) were copolymerized. Mention may be made of polymer resins for undercoat layers.
Examples of the monomer that can be used in the polymer resin for the undercoat layer include monomers described in paragraphs [0197] to [0210] of JP-A-2009-255434.

Various known methods can be used as a method of applying the undercoat layer coating solution containing the constituent material of the undercoat layer to the support. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.
The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / m ^2, and more preferably 1 to 50 mg / m ^2.

<Protective layer>
In the lithographic printing plate precursor according to the present invention, a protective layer is provided on the image recording layer as necessary in order to prevent the occurrence of scratches in the image recording layer, to block oxygen, and to prevent ablation during high-illuminance laser exposure. Can do.
Various studies have been made on the protective layer. For example, the protective layer is described in detail in US Pat. No. 3,458,311 and JP-B-55-49729.
As a material used for the protective layer, for example, materials described in paragraphs [0213] to [02227] of JP-A-2009-255434 (water-soluble polymer compounds, inorganic layered compounds, etc.) are used. be able to.

  The prepared protective layer coating solution is applied onto the image recording layer provided on the support and dried to form a protective layer. The coating solvent can be appropriately selected in relation to the binder, but when a water-soluble polymer is used, it is preferable to use distilled water or purified water. The coating method of the protective layer is not particularly limited, and examples thereof include a blade coating method, an air knife coating method, a gravure coating method, a roll coating coating method, a spray coating method, a dip coating method, and a bar coating method.

The coating amount of the protective layer, the coating amount after drying is preferably in the range of 0.01 to 10 g / m ^2, more preferably in the range of 0.02 to 3 g / m ^2, and most preferably 0. It is in the range of 02 to 1 g / m ² .

  The lithographic printing plate precursor according to the present invention having the image recording layer as described above exhibits excellent neglectability and printing durability when formed into a lithographic printing plate, and in the case of an on-press development type, on-press development. A lithographic printing plate precursor with improved properties is obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

<Manufacture of lithographic printing plate support>
The following treatments (a) to (n) were applied to an aluminum alloy plate of material 1S having a thickness of 0.3 mm to produce a lithographic printing plate support. In addition, the water washing process was performed between all the process steps, and the liquid draining was performed with the nip roller after the water washing process.

(A) Mechanical roughening treatment (brush grain method)
Using a device as shown in FIG. 7, a mechanical rough surface by a rotating bundle-planting brush while supplying a suspension of pumice (specific gravity 1.1 g / cm ³ ) as a polishing slurry to the surface of an aluminum plate. The treatment was performed. In FIG. 7, 1 is an aluminum plate, 2 and 4 are roller-like brushes (bundling brushes in this embodiment), 3 is a polishing slurry, and 5, 6, 7 and 8 are support rollers.
In the mechanical surface roughening treatment, the median diameter (μm) of the abrasive was 30 μm, the number of brushes was 4, and the number of rotations (rpm) of the brushes was 250 rpm. The material of the bunch planting brush was 6 · 10 nylon, with a bristle diameter of 0.3 mm and a bristle length of 50 mm. The brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. The distance between the two support rollers (φ200 mm) at the bottom of the bundle-planting brush was 300 mm. The bundle brush was pressed until the load of the drive motor for rotating the brush became 10 kW plus with respect to the load before the bundle brush was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate.

(B) Alkaline etching treatment The aluminum plate obtained above was etched by spraying a caustic soda aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% with a spray tube at a temperature of 70 ° C. Then, water washing by spraying was performed. The amount of aluminum dissolved was 10 g / m ² .

(C) Desmutting treatment in acidic aqueous solution Next, desmutting treatment was performed in an aqueous nitric acid solution. The nitric acid aqueous solution used for the desmut treatment was nitric acid used for electrochemical roughening in the next step. The liquid temperature was 35 ° C. The desmutting liquid was sprayed and sprayed for 3 seconds.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of nitric acid electrolysis 60 Hz. As the electrolytic solution at this time, an electrolytic solution in which aluminum nitrate was adjusted to 4.5 g / L by adding aluminum nitrate to an aqueous solution having a temperature of 35 ° C. and nitric acid of 10.4 g / L was used. The AC power supply waveform is the waveform shown in FIG. 5, the time tp until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, and the trapezoidal rectangular wave AC is used with the carbon electrode as the counter electrode. An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 6 was used. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. Amount of electricity (C / dm ²⁾ the aluminum plate was 185C / dm ² as the total quantity of electricity when the anode. Then, water washing by spraying was performed.

(E) Alkaline etching treatment The aluminum plate obtained above was etched by spraying an aqueous caustic soda solution having a caustic soda concentration of 5 mass% and an aluminum ion concentration of 0.5 mass% with a spray tube at a temperature of 50C. Then, water washing by spraying was performed. The amount of dissolved aluminum was 0.5 g / m ² .

(F) Desmutting treatment in acidic aqueous solution Next, desmutting treatment was performed in an aqueous sulfuric acid solution. The sulfuric acid aqueous solution used for the desmut treatment was a solution having a sulfuric acid concentration of 170 g / L and an aluminum ion concentration of 5 g / L. The liquid temperature was 60 ° C. The desmutting liquid was sprayed and sprayed for 3 seconds.

(G) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of hydrochloric acid electrolysis 60 Hz. As the electrolytic solution, an electrolytic solution in which aluminum chloride was adjusted to 4.5 g / L by adding aluminum chloride to an aqueous solution having a liquid temperature of 35 ° C. and hydrochloric acid of 6.2 g / L was used. The AC power supply waveform is the waveform shown in FIG. 5, the time tp until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, and the trapezoidal rectangular wave AC is used with the carbon electrode as the counter electrode. An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode. The electrolytic cell shown in FIG. 6 was used. The current density was 25A / dm ² at the peak of electric current amount of hydrochloric acid electrolysis (C / dm ²⁾ the aluminum plate was 63C / dm ² as the total quantity of electricity when the anode. Then, water washing by spraying was performed.

(H) Alkaline etching treatment The aluminum plate obtained above was etched by spraying a caustic soda aqueous solution having a caustic soda concentration of 5 mass% and an aluminum ion concentration of 0.5 mass% with a spray tube at a temperature of 50C. Then, water washing by spraying was performed. The amount of aluminum dissolved was 0.1 g / m ² .

(I) Desmutting treatment in acidic aqueous solution Next, desmutting treatment was performed in an aqueous sulfuric acid solution. Specifically, desmutting treatment was performed for 4 seconds at a liquid temperature of 35 ° C. using an aqueous sulfuric acid solution used in the anodizing step (dissolving 5 g / L of aluminum ions in an aqueous solution of 170 g / L sulfuric acid). The desmutting liquid was sprayed and sprayed for 3 seconds.

(J) First Anodizing Treatment A first stage anodizing treatment was performed using an anodizing apparatus using direct current electrolysis having the structure shown in FIG. Anodization was performed under the conditions shown in Table 1 to form an anodized film having a predetermined film thickness. The electrolytic solution used is an aqueous solution containing the components in Table 1.
In the anodizing apparatus 610, the aluminum plate 616 is transported as indicated by arrows in FIG. The aluminum plate 616 is charged (+) by the power supply electrode 620 in the power supply tank 612 in which the electrolytic solution 618 is stored. Then, the aluminum plate 616 is conveyed upward by the roller 622 in the power supply tank 612, and the direction is changed downward by the nip roller 624. Then, the aluminum plate 616 is conveyed toward the electrolytic treatment tank 614 in which the electrolytic solution 626 is stored, and by the roller 628. The direction is changed horizontally. Next, the aluminum plate 616 is charged to (−) by the electrolytic electrode 630 to form an anodized film on the surface thereof, and the aluminum plate 616 exiting the electrolytic treatment tank 614 is transported to a subsequent process. In the anodizing apparatus 610, the direction changing means is constituted by the roller 622, the nip roller 624 and the roller 628, and the aluminum plate 616 is disposed between the power supply tank 612 and the electrolytic treatment tank 614 between the rollers 622, 624 and 628. Thus, it is conveyed into a mountain shape and an inverted U shape. The feeding electrode 620 and the electrolytic electrode 630 are connected to a DC power source 634.

(K) Pore-wide treatment The above-mentioned anodized aluminum plate was immersed in an aqueous caustic soda solution having a temperature of 35 ° C., a caustic soda concentration of 5 mass%, and an aluminum ion concentration of 0.5 mass%, and the pore-wide treatment was performed. It was. Then, water washing by spraying was performed.
In addition, this process was not implemented in Examples 1-6, 13-14, 17-19, and Comparative Examples 1 and 3-9.

(L) Second Anodizing Treatment A second stage anodizing treatment was performed using a direct current electrolysis anodizing apparatus having the structure shown in FIG. Anodization was performed under the conditions shown in Table 1 to form an anodized film having a predetermined film thickness.
The electrolytic solution used is an aqueous solution containing the components in Table 1.

(M) Third Anodizing Treatment A third stage anodizing treatment was performed using an anodizing apparatus using direct current electrolysis having the structure shown in FIG. Anodization was performed under the conditions shown in Table 1 to form an anodized film having a predetermined film thickness. The electrolytic solution used is an aqueous solution containing the components in Table 1.
In addition, this process was implemented in Examples 4-20 and Comparative Examples 1-9.

(N) Silicate treatment In order to ensure the hydrophilicity of the non-image area, a silicate treatment was performed by dipping at 50 ° C. for 7 seconds using a 2.5 mass% No. 3 sodium silicate aqueous solution. The adhesion amount of Si was 8.5 mg / m ² . Then, water washing by spraying was performed.

  The average diameter (large-diameter hole portion) of the large-diameter hole portion in the anodized film having micropores after the second anodizing treatment step (or after the third anodizing treatment step) obtained above. Diameter), the average diameter (small diameter hole diameter) at the communication position of the small diameter hole, the depth of the large diameter hole and the small diameter hole, the thickness of the anodized film from the bottom of the small diameter hole to the aluminum plate surface ( Table 2 summarizes the barrier layer thickness), the shapes of the large-diameter holes and the small-diameter holes, the density of the small-diameter holes, and the ratio (small-diameter hole diameter / large-diameter hole diameter).

The average diameter of the micropores (average diameter of the large-diameter hole portion and the small-diameter hole portion) was obtained by observing N = 4 surfaces of the large-diameter hole surface and the small-diameter hole portion surface with an FE-SEM at a magnification of 150,000 times. In the obtained four images, the diameters of the micropores (large-diameter holes and small-diameter holes) existing in the range of 400 × 600 nm ² were measured and averaged. In addition, when the depth of the large-diameter hole portion was deep and it was difficult to measure the diameter of the small-diameter hole portion, the upper part of the anodized film was cut, and thereafter various diameters were obtained.
The depth of the micropores (depths of the large-diameter hole portion and the small-diameter hole portion) was obtained by observing the cross section of the support (anodized film) with FE-SEM (large-diameter hole depth observation: 150,000 times). , Small diameter hole depth observation: 50,000 times) In the obtained image, the depth of 25 arbitrary micropores was measured and averaged.

In addition, the electrolyte solution used at each process is an aqueous solution containing the components in Table 1. In Table 1, “-” means not implemented. In Table 1, “concentration” represents the concentration (g / l) of the component described in the “solution” column.
In Table 2, “communication density” means the density of the small diameter hole in the cross section of the anodized film at the communication position C between the small diameter hole and the large diameter hole. “Center density” means the density of the small diameter hole in the cross section of the anodized film at the center position in the depth direction of the small diameter hole (thickness direction of the anodized film) (corresponding to the center position P in FIG. 1). ). “Shape” in the large-diameter hole section means the shape of the large-diameter hole, and the case of a substantially straight tube is described as “straight tube”, and the diameter increases from the anodized film surface to the aluminum plate side. (In the case of a substantially conical shape) is expressed as “conical shape”. “Shape” in the small-diameter hole section means the shape of the small-diameter hole, and a case having a branch point is expressed as “dendritic”, and a case where there is no branch point and a substantially straight tube is expressed as “straight tube”.
In addition, when the shape of a large diameter hole part is conical, the average diameter (large diameter hole part diameter) in the anodic oxide film surface of a large diameter hole corresponds to a surface layer average diameter.

In Examples 1 to 20, micropores having a predetermined average diameter and depth were formed in the anodized film of aluminum.
The production conditions of Comparative Examples 10 to 14 are the same as those of Examples 1 to 5 described in paragraph [0136] of JP-A No. 11-219657. In Comparative Examples 10 to 14, a micropore having a substantially straight tubular small-diameter hole was formed.

<Manufacture of lithographic printing plate precursor>
The following undercoat layer coating solution was applied to each of the lithographic printing plate supports produced above so that the dry coating amount was 28 mg / m ² , thereby providing an undercoat layer.

<Coating liquid for undercoat layer>
-Undercoat layer compound (1) having the following structure: 0.18 g
・ Hydroxyethyliminodiacetic acid 0.10g
・ Methanol 55.24g
・ Water 6.15g

Next, the image recording layer coating solution is bar-coated on the undercoat layer formed as described above, and then oven-dried at 100 ° C. for 60 seconds to form an image recording layer having a dry coating amount of 1.3 g / m ^2. did.
All the image recording layer coating solutions were obtained by mixing and stirring the respective photosensitive solutions and microgel solutions immediately before coating.

<Photosensitive solution>
-Binder polymer (1) [the following structure] 0.24 g
Infrared absorber (1) [the following structure] 0.030 g
-Radical polymerization initiator (1) [the following structure] 0.162 g
Polymerizable compound Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
・ Low molecular weight hydrophilic compound tris (2-hydroxyethyl) isocyanurate
0.062g
・ Low molecular weight hydrophilic compound (1) [the following structure] 0.052 g
-Sensitizing agent Phosphonium compound (1) [the following structure] 0.055 g
・ Sensitizer Benzyl-dimethyl-octylammonium ・ PF ₆ salt 0.018g
-Betaine compound (C-1) [the following structure] 0.010 g
Fluorine-based surfactant (1) (average weight molecular weight: 10,000) [the following structure] 0.008 g
・ Methyl ethyl ketone 1.091g
・ 1-methoxy-2-propanol 8.609g

<Microgel solution>
・ Microgel (1) 2.640 g
・ Distilled water 2.425g

  The binder polymer (1), infrared absorber (1), radical polymerization initiator (1), phosphonium compound (1), low molecular weight hydrophilic compound (1), betaine compound (C-1), and fluorine-based interface The structure of the active agent (1) is as shown below.

  The microgel (1) described above is synthesized as follows.

<Synthesis of Microgel (1)>
As oil phase components, trimethylolpropane and xylene diisocyanate adduct (Takenate D-110N, manufactured by Mitsui Takeda Chemical Co., Ltd.) 10 g, pentaerythritol triacrylate (SR444, manufactured by Nippon Kayaku Co., Ltd.) 3.15 g, and Pionein A- 0.1 g of 41C (manufactured by Takemoto Yushi) was dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of PVA-205 was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 50 ° C. for 3 hours. The microgel solution thus obtained was diluted with distilled water to a solid content concentration of 15% by mass, and this was used as the microgel (1). When the average particle size of the microgel was measured by a light scattering method, the average particle size was 0.2 μm.

Then, a protective layer coating solution having the following composition was further bar-coated on the image recording layer formed as described above, and then oven-dried at 120 ° C. for 60 seconds to provide a dry coating amount of 0.15 g / m ² . A layer was formed to obtain a lithographic printing plate precursor.

<Coating liquid for protective layer>
・ Inorganic layered compound dispersion (1) 1.5 g
-Polyvinyl alcohol (CKS50, sulfonic acid modification, saponification degree 99 mol% or more, polymerization degree 300, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 6% by mass aqueous solution 0.55 g
-Polyvinyl alcohol (PVA-405, saponification degree 81.5 mol%, polymerization degree 500, Kuraray Co., Ltd.) 6 mass% aqueous solution 0.03g
-1% by weight aqueous solution of surfactant (Emalex 710, manufactured by Nippon Emulsion)
8.60g
・ Ion-exchanged water 6.0g

  The inorganic layered compound dispersion (1) described above is prepared as follows.

(Preparation of inorganic layered compound dispersion (1))
6.4 g of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) was added to 193.6 g of ion-exchanged water, and dispersed using an homogenizer until the average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed particles was 100 or more.

<Evaluation of planographic printing plate>
(On-press developability)
The resulting lithographic printing plate precursor was exposed under the conditions of an external drum rotation speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi using a Fujifilm Corporation Luxel PLASETTER T-6000III equipped with an infrared semiconductor laser. The exposure image includes a solid image and a 50% dot chart of a 20 μm dot FM screen.
The obtained exposed original plate was attached to a plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation without developing. Equality-2 (manufactured by FUJIFILM Corporation) / tap water = 2/98 (volume ratio) dampening water and Values-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) After dampening water and ink were supplied by the standard automatic printing start method of LITHRONE 26 and developed on the machine, 100 sheets were printed on Tokuhishi Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.
Measures the number of print sheets required until the on-press development on the printing machine in the unexposed area of the 50% halftone chart is completed and the ink is not transferred to the halftone dot non-image area as the on-press developability. did. In order from the one with the best on-machine developability, it was represented by ◎ (20 sheets or less of damaged paper), ○ (21 to 30 sheets of damaged paper), △ (31 to 40 sheets of damaged paper), × (41 or more sheets of damaged paper). . The results are shown in Table 3. In practice, it is preferably not x.

(Number of neglected payments)
After the on-press development is completed, after a good printed matter can be obtained, the printing is temporarily stopped, and the printing is resumed after being left on the printing press for 1 hour in a room at 25 ° C. and a humidity of 50%. Then, the number of damaged sheets of printing paper required until a good print with no stain was obtained was evaluated. In order from the one with the best neglectability, it was represented by ◎ (75 sheets or less of damaged paper), ○ (76 to 200 sheets of damaged paper), △ (201 to 300 sheets of damaged paper), × (301 or more sheets of damaged paper). The results are shown in Table 3. In practice, it is preferably not x.

(Print life)
After on-press development using the same printing machine and method as described above, printing was further continued. The printing durability was evaluated based on the number of printed sheets when it was visually recognized that the density of the solid image started to decrease. XX for printing less than 10,000 pages XX, 10000 for 10,000 or more and less than 15,000 pages, XX for 15,000 or more and less than 20,000 pages, 20,000 or more 2 Those with less than 55,000 sheets were rated as ○, those with 25,000 or more but less than 30,000 were ◎, and those with 30,000 or more were rated as ◎◎. The results are shown in Table 3.
In practice, it is preferable not to be “xxx”, “xxx”, or “x”.

(Scratch resistance)
The scratch resistance of the lithographic printing plate support was evaluated by a scratch test on the surface of the obtained lithographic printing plate support.
The scratch test was performed using a continuous load-type scratch strength tester (SB-53, manufactured by Shinto Kagaku Co., Ltd.) under the conditions of a sapphire needle of 0.4 mmφ and a needle moving speed of 10 cm / second under a load of 100 g.
As a result, the case where scratches by the needle did not reach the surface of the aluminum alloy plate (base) was evaluated as “◯” as being excellent in scratch resistance, and the case where it was reached was evaluated as “×”. The support for a lithographic printing plate having a weight value of 100 g and excellent scratch resistance can suppress the transfer of scratches to the image recording layer during winding and lamination when it is used as a lithographic printing plate precursor. Dirt can be suppressed.

As shown in Table 3 above, a lithographic printing plate and a lithographic printing plate precursor using a lithographic printing support provided with an anodic oxide coating of aluminum on which micropores having an average diameter and depth in a predetermined range are formed (implementation) In Examples 1 to 20), it was confirmed that excellent printing durability, neglectability, on-press developability and scratch resistance were exhibited.
In addition, the shape of the large diameter hole part which comprises the micropore obtained in Examples 1-6, 13-14, and 17-19 becomes large in diameter toward the aluminum plate side from the anodized film surface (surface layer average). The bottom average diameter was larger than the diameter). In this example, the difference between the bottom average diameter and the surface average diameter was about 25 nm.
Moreover, the shape of the large diameter hole part which comprises the micropore obtained in Examples 5-12, 15-16, and 20 was a substantially straight tube shape.
Furthermore, in Examples 1-20, the shape of the small diameter hole part was dendritic. In Examples 4 to 20, the small-diameter hole portion was constituted by a substantially straight main hole portion and a substantially conical diameter-enlarged hole portion as shown in FIG. The maximum value of the expanded hole portion was about 1 to 8 nm larger than the maximum value of the main hole portion. Further, the ratio of the main hole portion to the total depth of the small diameter hole portion was about 90%.

On the other hand, in Comparative Examples 1 to 14 that do not satisfy the relationship between the average diameter and depth of the present invention, only inferior results were obtained as compared with Examples 1 to 20.
In particular, Comparative Examples 10 to 14 reproducing Examples 1 to 5 specifically disclosed in JP-A No. 11-291657 have inferior results in neglectability, on-press developability, and scratch resistance. It was.

(Pots-like stain resistance)
The obtained lithographic printing plate precursor was conditioned with interleaving paper at 25 ° C. and 70% RH for 1 hour, packaged with aluminum kraft paper, and then heated in an oven set at 60 ° C. for 10 days. .
Thereafter, the temperature was lowered to room temperature, and after on-press development was performed with the same printing machine and method as described above, 500 sheets were printed. The 500th printed matter was visually confirmed, and the number of print stains of 20 μm or more per 80 cm ² was calculated. The results are shown in Table 3.
The number of spot-like stains was 250 or more, “XX”, 150 or more and less than 250 “×”, and less than 150 “◯”.
In practice, it is preferably not “XX” or “X”.
When the above-mentioned pot-like stain resistance was evaluated using the lithographic printing original plate obtained in Examples 4 to 20, it was “◯” in Examples 4 to 20.
On the other hand, when the spot-like stain resistance was evaluated using the lithographic printing original plates obtained in Comparative Examples 10 and 13, it was “x” in Comparative Example 10 and “xxx” in Comparative Example 13.

DESCRIPTION OF SYMBOLS 1,12 Aluminum plate 2, 4 Roller-like brush 3 Polishing slurry liquid 5, 6, 7, 8 Support roller ta Anode reaction time tc Cathode reaction time tp Time until current reaches peak from 0 Ia At peak time on anode cycle side Current Ic Peak current on the cathode cycle side 10, 10a, 10b Lithographic printing plate support 14, 14a, 14b, 14c, 14d Aluminum anodic oxide coating 16, 16a, 16b, 16c, 16d Micropore 18, 18a Large Diameter hole portion 20, 20a Small diameter hole portion 30 Large diameter hole portion 32 Main hole portion 50 Main electrolytic cell 51 AC power source 52 Radial drum roller 53a, 53b Main electrode 54 Electrolytic solution supply port 55 Electrolytic solution 56 Auxiliary anode 60 Auxiliary anode vessel W Aluminum plate 610 Anodizing device 612 Power supply tank 614 Electrolytic treatment tank 616 Aluminum plate 618, 626 Electrolyte 620 Feed electrode 622, 628 Roller 624 Nip roller 630 Electrode electrode 632 Tank wall 634 DC power supply

Claims (5)

A lithographic printing plate support comprising an aluminum plate and an aluminum anodized film thereon, and having micropores extending in the depth direction from the surface opposite to the aluminum plate in the anodized film. ,
The micropore communicates with a large-diameter hole extending from the surface of the anodized film to a position having a depth of 5 to 60 nm (depth A) and a bottom of the large-diameter hole, and having a depth of 900 to 2000 nm from the communication position. Consists of a dendritic small-diameter hole extending while branching to a position,
The average diameter (large-diameter hole diameter) of the large-diameter hole on the surface of the anodized film is 10 to 100 nm, and the large-diameter hole diameter and the depth A are (depth A / large-diameter hole diameter) = Satisfies the relationship of 0.1 to 4.0,
The average diameter (small diameter hole diameter) at the communication position of the small diameter hole is greater than 0 and less than 20 nm,
A lithographic printing support having a ratio of the large-diameter hole diameter to the small-diameter hole diameter (small-diameter hole diameter / large-diameter hole diameter) of 0.85 or less.   The lithographic printing plate support according to claim 1, wherein the thickness of the anodized film from the bottom of the small-diameter hole to the surface of the aluminum plate is 20 nm or more. The support for a lithographic printing plate according to claim 1 or 2, wherein a density of the small-diameter holes in the cross section of the anodized film at the communication position is 100 to 3000 / μm ² . The density (density B) of the small diameter hole in the cross section of the anodized film at the center position in the depth direction of the small diameter hole is the density (density A) of the small diameter hole in the cross section of the anodized film at the communication position. The lithographic printing plate support according to any one of claims 1 to 3, wherein the support is larger and the density B is 300 to 9000 pieces / µm ² . A planographic printing plate precursor comprising an image recording layer on the planographic printing plate support according to any one of claims 1 to 4.