JP4362053B2 - Lithographic printing plate support and lithographic printing plate precursor using the same - Google Patents

Description

  The present invention relates to a support for a lithographic printing plate and a lithographic printing plate precursor, and in particular, when used as a lithographic printing plate, it is possible to achieve both stain resistance and printing durability, and to generate a pot-like residual film. The present invention relates to a lithographic printing plate support having an optimum surface shape and a lithographic printing plate precursor using the same.

  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, clogging of the shadow portion occurs unless dampening water is increased during printing. Therefore, the so-called water width is narrowed.

On the other hand, if there is a deep concave portion on the surface of the support that has been subjected to the roughening treatment, the image recording layer in that portion becomes thick, and thus development may be suppressed in shape. As a result of the development being suppressed, the image recording layer remains in the deep concave portion, and a local residual film (hereinafter also referred to as a “pot-like residual film”) is generated in the non-image portion. There is a problem that the non-image area is stained. For example, in a lithographic printing plate precursor provided with a so-called thermal type image recording layer in which the solubility in an alkali developer changes due to heat generated by photothermal conversion, the image formation reaction is insufficient at the bottom of the recess, and the pot-like residual film Occurs.
Such a pot-like residual film is likely to occur when the conditions of exposure and development are severe. For example, in a planographic printing plate precursor provided with a thermal type image recording layer, the exposure time is shortened to improve productivity, or the laser beam energy is lowered to extend the life of the laser. This is a case where the exposure amount is reduced. In addition, in order to use an image recording layer that tends to cause image omission in a portion that should originally become an image portion with respect to a highly active developer with high sensitivity, there is a case where development is performed using a developer with low sensitivity. is there.

In order to obtain a lithographic printing plate support having good performance, it is common to roughen the surface of the aluminum plate to give irregularities. As for the unevenness, various shapes (structures) have been proposed as shown below.
For example, a triple structure having a large wave, a medium wave and a small wave defining the opening diameters of the medium wave and the small wave (see Patent Document 1), and a structure defining the diameter of the small wave in a large and small double structure (for example, Patent Document 2) , See Patent Document 3), a technique for providing fine protrusions in addition to large and small double recesses (pits) (see Patent Document 4), and a double structure that defines an opening diameter (see Patent Document 5). ), A double structure (see Patent Document 6) defining a factor a30 indicating the smoothness of the surface, and a plurality of electrochemical roughening treatments (hereinafter also referred to as “electrolytic roughening treatment”). A structure (see Patent Document 7) that defines the ratio of the pit diameters to be formed has been proposed.

  This graining includes mechanical graining methods such as ball graining, brush graining, wire graining, and blast graining, and an electrolytic grained surface for electrolytic etching of an aluminum plate in an electrolyte containing hydrochloric acid and / or nitric acid. And a composite roughening method (see Patent Document 8) in which a mechanical roughening method and an electrolytic roughening method are combined.

JP-A-8-300844 JP 11-99758 A Japanese Patent Laid-Open No. 11-208138 JP 11-167207 A Japanese Patent No. 2023476 JP-A-8-300843 Japanese Patent Laid-Open No. 10-35133 US Pat. No. 4,476,006

However, in the above prior art, the stain resistance and the printing durability are in a trade-off relationship, and it is impossible to achieve both the stain resistance and the printing durability.
Therefore, the present invention solves this problem, can achieve both excellent stain resistance and high printing durability, and further includes a lithographic printing plate precursor free from the occurrence of a pot-like residual film and the lithographic printing used therefor An object is to provide a plate support.

In order to solve the above problems, the present inventor has intensively studied the size of the concavo-convex structure on the surface of the lithographic printing plate support, the combination thereof, etc. As a result, the surface has a centerline average roughness R in a specific range. was adjusted to _a, formed by combining a concavo-convex structure of a particular size, further, when reducing the number of depth 3μm or more recesses in the three-dimensional data, the balance between stain resistance and printing durability at high levels It can be maintained, and was Heading that there is no occurrence of pepper-like residual film even tightened condition of the exposure and development.
Moreover, when reducing the number of depth 4μm or more recesses in the three-dimensional data, the center line average roughness R _a in the range and depth 3μm or more recesses number more similarly stain resistance even in the wide range of the It was found that the balance with the printing durability could be maintained at a high level, and that no spot-like residual film was generated even when the conditions of exposure and development were strict, and the present invention was completed.

That is, the present invention provides the following (1) to ( 4 ).

( 1 ) A lithographic printing plate support obtained by subjecting an aluminum plate to a surface roughening treatment and an anodizing treatment,
The center line average roughness _Ra is less than 0.60 μm,
The grain shape of the surface is a structure in which a large wave structure with an average wavelength of 5 to 100 μm, a medium wave structure with an average opening diameter of 0.5 to 5 μm, and a small wave structure with an average opening diameter of 0.01 to 0.2 μm are superimposed. ,And,
For lithographic printing plates in which the number of recesses having a depth of 3 μm or more existing on the surface is 10 to 120 / mm ² and the number of recesses having a depth of 4 μm or more existing on the surface is 20 / mm ² or less Support.

( 2 ) In the aluminum plate, Fe is 0.20 to 0.50% by mass, Si is 0.03 to 0.15% by mass, Ti is 0.05% by mass or less, and Cu is 0.020 to 0%. The support for a lithographic printing plate as described in (1) above, which is an aluminum plate containing 0.040% by mass and the balance being Al and inevitable impurities.

( 3 ) The lithographic printing plate support according to (1) or (2) , wherein the average ratio of the depth to the opening diameter of the small wave structure is 0.2 or more.

( 4 ) A lithographic printing plate precursor comprising an image recording layer provided on the lithographic printing plate support according to any one of (1) to ( 3 ) above.

By using the lithographic printing plate support of the present invention characterized by the surface shape, the balance of stain resistance and printing durability that could not be removed from the conventional trade-off relationship is maintained at a high level, and exposure and development are performed. Even if the conditions are strict, the generation of a pot-like residual film can be suppressed.
Further, if an aluminum plate having a specific Cu content is used, the balance between stain resistance and printing durability can be maintained at a higher level.

Hereinafter, the present invention will be described in detail.
[Support for lithographic printing plate]
<Surface grain shape>
The first aspect of the flat plate printing plate support (hereinafter, also referred to as "first aspect of the lithographic printing plate support of the present invention".) Has a center line average roughness R _a after the roughening treatment is 0 Less than .55 μm, and the surface has a grain shape of a large wave structure with an average wavelength of 5 to 100 μm, a medium wave structure with an average opening diameter of 0.5 to 5 μm, and a small wave structure with an average opening diameter of 0.01 to 0.2 μm. A support for a lithographic printing plate, wherein the number of concave portions having a depth of 3 μm or more present on the surface is 10 to 60 / mm ² .

The inventor forms the surface of the support for a lithographic printing plate by combining the center line average roughness Ra of _a specific range and the uneven structure of _a specific size, and further has a depth of 3 μm existing on the surface. If the number of the above recesses is in a specific range, the balance between the stain resistance and the printing durability can be maintained at a high level, and even if the exposure and development conditions are strict, the occurrence of a pot-like residual film is generated. As a result, the first embodiment of the lithographic printing plate support of the present invention was completed.

The second aspect of the lithographic printing plate support of the present invention, the center line average roughness R _a after the roughening treatment is less than 0.60 .mu.m, grain shape of the surface, the mean wavelength 5~100μm of A structure in which a large wave structure, a medium wave structure with an average opening diameter of 0.5 to 5 μm, and a small wave structure with an average opening diameter of 0.01 to 0.2 μm are superimposed, and the number of recesses having a depth of 3 μm or more present on the surface there is a 10 to 120 pieces / mm ^2, a further support for a lithographic printing plate number of depth 4μm or more recesses present in said surface, characterized in that 20 or / mm ² or less.

The present inventors, when the depth 4μm or more recesses present in the surface to 20 / mm ² or less, the range of center line average roughness R _a in the first aspect of the lithographic printing plate support of the present invention In addition, even if the number of recesses having a depth of 3 μm or more existing on the surface is made wider, the balance between stain resistance and printing durability can be maintained at a high level, and the conditions for exposure and development can be maintained. It was found that even if it was strict, there was no occurrence of a pot-like residual film, and the second embodiment of the lithographic printing plate support of the present invention was completed.

Center line average roughness R _a of the surface of the lithographic printing plate support of the present invention, represents the state of the unevenness of the surface of the support.
In a first aspect of the lithographic printing plate support of the present invention, the center line average roughness R _a of the surface after the roughening treatment is less than 0.55 .mu.m.
In a first aspect of the lithographic printing plate support of the present invention, when R _a of the surface with a recess for a specific number of 3μm or more depths have grain structure to be described later is less than 0.55 .mu.m, lithographic printing Printing durability, stain resistance, and exposure stability can be achieved at a high level in a well-balanced manner.
When _Ra is 0.55 μm or more, the depth of the unevenness may be deep and a pot-like residual film may be generated.
Further, if the depth of the unevenness is shallow, the hydrophilicity of the support is lowered, ink may adhere to the non-image area during printing, and the blanket cylinder may be soiled, and so-called background soiling may occur. Further, if the depth of the unevenness is shallow, the water retention of the support is lowered, and if the fountain solution is not increased at the time of printing, the shadow portion is clogged. That is, the so-called water width is narrowed. Furthermore, if deposits such as ink components or paper dust adhere to the surface of the non-image area, the water retention amount decreases rapidly, and the ink moves along the deposit, so the image area (halftone dot) Ink easily moves to the adjacent non-image area. As a result, ink entanglement tends to occur.

In the first aspect of the lithographic printing plate support of the present invention, R _a is less than 0.55 μm and 0.50 μm or less in that these excellent performances can be realized in a more balanced manner. Is preferred.
Furthermore, R _a is the occurrence of background stain as described above, in that suppress the occurrence of entanglement of the ink, is preferably at least 0.40 .mu.m, and more preferably 0.45μm or more.

In a second aspect of the lithographic printing plate support of the present invention, the center line average roughness R _a of the surface after the roughening treatment is less than 0.60 .mu.m.
In a second aspect of the lithographic printing plate support of the present invention, R _a surface having a concave recess and 4μm or more of the depth of a certain number of 3μm or more depths have grain structure to be described later 0. When the thickness is less than 60 μm, the printing durability, stain resistance, and exposure stability when a lithographic printing plate is formed can be realized with a high level of balance.
When _Ra is 0.60 μm or more, the depth of the unevenness may be so deep that a pot-like residual film may be generated.
In addition, if the depth of the unevenness is shallow, as in the first aspect of the lithographic printing plate support of the present invention, scumming may occur, the water width becomes narrower, and further ink entanglement occurs. It becomes easy.

In the present invention (the lithographic printing plate support of the first and second aspects), the measuring method of a center line average roughness R _a of the surface is as follows.
Two-dimensional roughness measurement is performed with a stylus type roughness meter (for example, sufcom 575, manufactured by Tokyo Seimitsu Co., Ltd.), the average roughness defined in ISO 4287 is measured five times, and the average value is set as the centerline average roughness. .
The conditions for the two-dimensional roughness measurement are shown below.
Cut-off value 0.8mm, tilt correction FLAT-ML, measurement length 3mm, vertical magnification 10,000 times, scanning speed 0.3mm / sec, stylus tip diameter 2μm

The support for a lithographic printing plate of the present invention has a large wave structure with an average wavelength of 5 to 100 μm and an average opening diameter of 0.5 to 5 μm with a medium wave structure and an average on the surface in both the first and second embodiments. It has a grain shape with a structure in which a small wave structure with an opening diameter of 0.01 to 0.2 μm is superimposed.
In the present invention, the large wave structure having an average wavelength of 5 to 100 μm has an effect of increasing the water retention amount on the surface of the non-image portion of the planographic printing plate. The more water held on the surface, the less the surface of the non-image area is affected by contamination in the atmosphere, and a non-image area that is less likely to get dirty even when the plate is left in the middle of printing can be obtained.
If the large wave structure is formed, it becomes easy to visually confirm the amount of dampening water given to the printing plate during printing. That is, the plate inspection property of the planographic printing plate is excellent. If the average wavelength of the large wave structure is less than 5 μm, there may be no difference from the medium wave structure. If the average wavelength of the large wave structure exceeds 100 μm, the exposed non-image area may appear glaring after exposure and development, which may impair plate inspection. The average wavelength of the large wave structure is preferably 10 to 80 μm.

  The medium wave structure having an average aperture diameter of 0.5 to 5 μm superimposed on the large wave structure has a function of holding the image recording layer mainly by an anchor (throwing) effect and imparting printing durability. When the average opening diameter of the pits having a medium wave structure is less than 0.5 μm, the adhesiveness with the image recording layer provided on the upper layer is lowered, and the printing durability of the lithographic printing plate may be lowered. Further, when the average opening diameter of the pits having the medium wave structure exceeds 5 μm, the number of pit boundary portions serving as anchors is reduced, so that the printing durability may also be lowered.

  The small wave structure having an average opening diameter of 0.01 to 0.2 μm superimposed on the medium wave structure mainly plays a role of improving stain resistance. By combining the medium wave structure with the small wave structure, when dampening water is supplied to the lithographic printing plate during printing, a water film is uniformly formed on the surface of the lithographic printing plate, thereby suppressing the occurrence of stains on the non-image area. it can. When the average opening diameter of the pits having the small wave structure is less than 0.01 μm, a large effect may not be obtained in forming a water film. On the other hand, when the average opening diameter of the pits having the small wave structure exceeds 0.2 μm, the medium wave structure is destroyed, and the effect of improving the printing durability by the above-described medium wave structure may not be obtained.

  With this small wave structure, not only the opening diameter of the pit but also the depth of the pit can be controlled to obtain even better stain resistance. That is, it is preferable that the average of the ratio of the depth to the opening diameter of the small wave structure is 0.2 or more. As a result, the uniformly formed water film is reliably held on the surface, and the stain resistance of the surface of the non-image part is maintained for a long time.

  In the present invention, the average wavelength of the surface large wave structure, the average aperture diameter of the medium wave structure, the average aperture diameter of the small wave structure, and the average depth measurement method for the aperture diameter are as follows.

(1) the average wavelength stylus roughness meter large wave structure performs a two-dimensional roughness measurement, the average peak distance S _m as defined in ISO4287 were measured 5 times, and the average value as the average wavelength.

(2) Average aperture diameter of medium wave structure The surface of the support was photographed at a magnification of 2000 times from directly above using an electron microscope. At least 50 pits (medium wave pits) are extracted, and the diameter is read to obtain the opening diameter, and the average opening diameter is calculated. The same method is used for a structure with a large wave structure superimposed.
In addition, in order to suppress variation in measurement, it is possible to perform equivalent circle diameter measurement using commercially available image analysis software. In this case, the electron micrograph is captured by a scanner, digitized, and binarized by software, and then an equivalent circle diameter is obtained.
As a result of measurement by the present inventor, the result of visual measurement and the result of digital processing showed almost the same value. The same applies to the structure in which the large wave structure is superimposed.

(3) Average aperture diameter of the small wave structure The surface of the support was photographed at a magnification of 50000 times from directly above using a high resolution scanning electron microscope (SEM), and the pit (small wave pit) of the small wave structure in the obtained SEM photograph At least 50 are extracted, the diameter is read and set as the opening diameter, and the average opening diameter is calculated.

(4) Average ratio of depth to aperture diameter of wavelet structure The average ratio of depth to aperture diameter of wavelet structure is obtained by photographing the fracture surface of the support at a magnification of 50000 using a high-resolution SEM. In the SEM photograph, at least 20 wavelet pits are extracted, the aperture diameter and depth are read, the ratio is obtained, and the average value is calculated.

The first aspect of the lithographic printing plate support of the present invention, as described above, has a center line average roughness _Ra of less than 0.55 μm, and has a grained structure with a structure superimposed on the surface thereof, The number of recesses having a depth of 3 μm or more present on the surface is 10 to 60 / mm ² . As a result, both excellent stain resistance and high printing durability can be achieved, and even if exposure and development conditions are strict, no spot-like residual film is generated.
In addition, as described above, the second aspect of the lithographic printing plate support of the present invention has a centerline average roughness _Ra of less than 0.60 μm, and has a grained shape with a structure superimposed on the surface thereof. The number of recesses having a depth of 3 μm or more existing on the surface is 10 to 120 / mm ² , and the number of recesses having a depth of 4 μm or more existing on the surface is 20 / mm ² or less. As a result, both excellent stain resistance and high printing durability can be achieved, and even if exposure and development conditions are strict, no spot-like residual film is generated.

  As a result of earnest research on the relationship between the pot-like residual film and the deep concave portion of the support surface that causes the pop-like residual film, the number of concave portions having a depth of 3 μm or more present on the surface is the cause of the generation of the pot-like residual film. As a result, the present invention (first aspect) has been completed. In addition, the inventors have found that the number of recesses having a depth of 4 μm or more existing on the surface is more strongly related to the generation of a pot-like residual film, and have completed the present invention (second embodiment).

In the present invention, the method for measuring the number of recesses having a depth of 3 μm or more and the number of recesses having a depth of 4 μm or more are as follows.
Using a laser microscope, the surface of 400 μm × 400 μm (also referred to as “400 μm □” in the present invention) is scanned in a non-contact manner at a pitch of 0.01 μm to obtain three-dimensional data, and this three-dimensional data has a depth of 3 μm. The number of the recesses described above and the number of recesses having a depth of 4 μm or more are counted.

As a result of earnest research on the cause of the formation of a concave portion having a depth of 3 μm or more (including a concave portion having a size of 4 μm or more) by the roughening treatment described later, the present inventor estimated the cause as follows.
First, when a roughening process including a mechanical roughening process is performed, the ridges of the abrasive particles used in the mechanical roughening process pierce deeply into the surface of the aluminum plate to form a recess. To be done.
Second, when a roughening treatment including an electrolytic roughening treatment is performed, the current is concentrated at a specific location during the electrolytic roughening treatment.

As a result of estimating the cause in this way and further earnestly researching, the present inventor has 120 recesses / mm ² or less, preferably not more than 3 μm deep recesses generated by the roughening treatment by the following means. 60 / mm ² can be below, and was the depth 4μm or more recesses produced by roughening found to be able to 20 / mm ² or less.
That is, the following means (i) to (v) have been found for the piercing of abrasive particles used in the mechanical roughening treatment, which is the first cause.
(I) An abrasive having a small particle size is used.
For example, sedimentation separation is performed to remove large particles, and only small particles are used, or the particles of the abrasive are brought into contact with each other by re-grinding to reduce the particle size of the abrasive. can do.
(Ii) An abrasive with particles having few sharp edges is used.
Pumiston (hereinafter also referred to as “pumice”), which is usually used for mechanical surface roughening, is obtained by crushing volcanic ash. Yes. On the other hand, silica sand has a shape close to a dodecahedron or a 24-hedron, and has little sharpness.

(Iii) The bristle used for the mechanical surface roughening treatment is softened.
For example, by using a brush with a thin bristle diameter or using a soft brush, the brush hair can be softened.
(Iv) The rotational speed of the brush used for the mechanical surface roughening process is lowered.
By appropriately giving “escape” time to the abrasive particles contained in the slurry liquid, sticking is suppressed.
(V) Lowering the pressing pressure (load) of the brush used for the mechanical surface roughening treatment.

Further, the following means (vi) to (viii) have been found with respect to the fact that the current is concentrated at a specific location during the electrolytic surface-roughening treatment as the second cause.
(Vi) When an electrolytic solution mainly composed of nitric acid is used in the electrolytic surface-roughening treatment, the amount of Cu in the alloy component of the aluminum plate is lowered so that electrolysis can easily occur uniformly.
In the electrolytic surface-roughening treatment, a smut in which the aluminum dissolution reaction (pitting reaction) and the components generated by the dissolution are reattached to the dissolution reaction part by applying an alternating current in an acidic electrolytic solution. Adhesion reactions occur alternately according to an alternating cycle. Here, when the nitric acid electrolyte is used, it is very easily affected by the type and amount of alloy components contained in the aluminum plate, and particularly, the influence of Cu is large. This is presumably because the surface resistance during the electrolytic surface-roughening treatment increases due to the presence of Cu. Therefore, by setting the amount of Cu in the alloy component to 0.040% by mass or less, the surface resistance during the electrolytic surface roughening treatment is reduced, so that current concentration is suppressed and uniform without forming coarse pits. Pits can be formed on the entire surface.

(Vii) When an electrolytic solution mainly composed of nitric acid is used in the electrolytic surface roughening treatment, pre-electrolysis is performed before the electrolytic surface roughening treatment.
In pre-electrolysis, the starting point of pit formation can be formed uniformly. Thereby, uniform pits can be formed on the entire surface without forming coarse pits in the subsequent electrolytic surface roughening treatment.

By such means as described above, the number of depth 3μm or more recesses on the surface 120 / mm ² or less, preferably can be 60 pieces / mm ² or less, Re soil resistance is less than 10 / mm ² Sexuality may worsen. This is because when printing is performed, particularly when printing is performed in such a condition that the plate surface dries in the middle of printing (for example, when printing is temporarily interrupted), a deep recess in the non-image portion of the planographic printing plate is retained This is probably because the fountain solution suppresses the adhesion of dirt to the plate surface. Therefore, in the first aspect of the lithographic printing plate support of the present invention, the depth existing on the surface is excellent in that it is excellent in stain resistance and does not generate a pot-like residual film even if the conditions of exposure and development are strict. The number of recesses of 3 μm or more is 10 to 60 / mm ² . Similarly, in the second embodiment of the lithographic printing plate support of the present invention, the depth existing on the surface is excellent in that it is excellent in stain resistance and does not generate a pot-like residual film even when the exposure and development conditions are strict. The number of recesses of 3 μm or more is 10 to 120 / mm ² .

In the second aspect of the lithographic printing plate support of the present invention, the number of recesses having a depth of 4 μm or more present on the surface is further 20 / mm ² or less. By making the number of recesses with a depth of 4 μm or more present on the surface strongly affected by the generation of a pot-like residual film within the above range, the generation of a pot-like residual film can be achieved without impairing excellent printing durability and stain resistance. In addition, the range of the center line average roughness _Ra and the number of recesses having a depth of 3 μm or more present on the surface in the first embodiment of the lithographic printing plate support of the present invention can be broadened. .

As described above, the lithographic printing plate support of the present invention is free from the occurrence of a pot-like residual film and excellent in stain resistance and printing durability when used in a lithographic printing plate. In one embodiment, the center line average roughness _Ra is less than 0.55 μm, and the surface has a grain shape of a large wave structure with an average wavelength of 5 to 100 μm and a medium wave structure with an average aperture diameter of 0.5 to 5 μm. A structure in which a small wave structure having an average opening diameter of 0.01 to 0.2 μm is superposed, and the number of recesses having a depth of 3 μm or more existing on the surface is set to 10 to 60 / mm ² .

Similarly, the second embodiment of the support for a lithographic printing plate of the present invention is free from the occurrence of a pot-like residual film and is excellent in stain resistance and printing durability when used as a lithographic printing plate. , The center line average roughness _Ra is less than 0.60 μm, and the surface has a grainy shape with a large wave structure with an average wavelength of 5 to 100 μm and a medium wave structure with an average opening diameter of 0.5 to 5 μm. A structure in which a small wave structure having a diameter of 0.01 to 0.2 μm is superimposed, the number of recesses having a depth of 3 μm or more existing on the surface is 10 to 120 / mm ^2, and the depth existing on the surface is 4 μm. The number of the concave portions is 20 pieces / mm ² or less.

<Surface treatment>
The lithographic printing plate support of the present invention is one in which the above-mentioned surface grain shape is formed on the surface of the aluminum plate by subjecting the aluminum plate described later to surface treatment. The lithographic printing plate support of the present invention is obtained by subjecting an aluminum plate to a surface roughening treatment and an anodizing treatment, but the production process of this support is not particularly limited, and the surface roughening treatment and the anodizing treatment are performed. Various processes other than the above may be included.
In the following, as a representative method for forming the above-described surface grain shape,
A method of sequentially performing mechanical surface roughening treatment, alkali etching treatment, desmutting treatment with an acid and electrochemical surface roughening treatment using an electrolytic solution on an aluminum plate,
A method of performing mechanical surface roughening treatment, alkaline etching treatment, desmutting treatment with acid and electrochemical surface roughening treatment using different electrolytes a plurality of times on an aluminum plate,
A method of sequentially performing an alkali etching treatment, an acid desmutting treatment on an aluminum plate, and an electrochemical surface roughening treatment using an electrolytic solution,
Examples include a method of subjecting an aluminum plate to alkali etching treatment, desmutting treatment with an acid, and electrochemical surface roughening treatment using different electrolytic solutions a plurality of times, but the present invention is not limited thereto. In these methods, after the electrochemical surface roughening treatment, an alkali etching treatment and an acid desmutting treatment may be further performed.
The lithographic printing plate support of the present invention obtained by these methods has a structure in which three or more kinds of irregularities with different periods are superimposed on the surface, and is resistant to stain and resistance when used as a lithographic printing plate. Excellent printability.
Hereinafter, each step of the surface treatment will be described in detail.

<Mechanical roughening>
The mechanical roughening treatment is effective as a roughening treatment means because it can form an uneven surface with an average wavelength of 5 to 100 μm at a lower cost than the electrochemical roughening treatment. is there.
Examples of the mechanical surface roughening treatment include, for example, a wire brush grain method in which the aluminum surface is scratched with a metal wire, a ball grain method in which the aluminum surface is grained with a polishing ball and an abrasive, JP-A-6-135175, and Japanese Patent Publication A brush grain method in which the surface is grained with a nylon brush and an abrasive described in Japanese Patent No. 50-40047 can be used.
A transfer method in which the uneven surface is pressed against the aluminum plate can also be used. That is, in addition to the methods described in JP-A-55-74898, JP-A-60-36195, and JP-A-60-20396, transfer is performed several times. The method described in Japanese Patent Application No. -55871 and Japanese Patent Application No. 4-204235 (Japanese Patent Laid-Open No. 6-24168) characterized in that the surface is elastic is also applicable.

In addition, by using electric discharge machining, shot blasting, laser, plasma etching, etc., a method of performing repetitive transfer using a transfer roll in which fine irregularities are etched, and an uneven surface coated with fine particles on an aluminum plate It is also possible to use a method in which an uneven pattern corresponding to the average diameter of the fine particles is repeatedly transferred to the aluminum plate a plurality of times by contacting the surface and applying a pressure a plurality of times from above. As a method for imparting fine irregularities to the transfer roll, known methods described in JP-A-3-8635, JP-A-3-66404, JP-A-63-65017, etc. may be used. it can. Further, a fine groove may be cut in two directions using a die, a cutting tool, a laser, or the like on the roll surface, and a square unevenness may be formed on the surface. The roll surface may be subjected to a known etching process or the like so that the formed square irregularities are rounded.
Further, in order to increase the surface hardness, quenching, hard chrome plating, or the like may be performed.
In addition, as the mechanical roughening treatment, methods described in JP-A Nos. 61-162351 and 63-104889 can be used.
In the present invention, the above-described methods can be used in combination in consideration of productivity and the like. These mechanical surface roughening treatments are preferably carried out before the electrochemical surface roughening treatment.

Hereinafter, the brush grain method used suitably as a mechanical roughening process is demonstrated.
The brush grain method generally uses a roller-shaped brush in which a large number of brush hairs such as synthetic resin hair made of synthetic resin such as nylon (trade name), propylene, and vinyl chloride resin are implanted on the surface of a cylindrical body. This is carried out by rubbing one or both of the surfaces of the aluminum plate while spraying a slurry liquid containing an abrasive on a rotating roller brush. Instead of the roller brush and the slurry liquid, a polishing roller which is a roller having a polishing layer on the surface can be used.
When using a roller brush, the flexural modulus is preferably 10,000 to 40,000 kg / cm ² , more preferably 15,000 to 35,000 kg / cm ² , and the bristle strength is preferably Brush hair that is 500 g or less, more preferably 400 g or less is used. The diameter of the brush bristles is generally 0.2 to 0.9 mm. The length of the brush bristles can be appropriately determined according to the outer diameter of the roller brush and the diameter of the body, but is generally 10 to 100 mm.
In particular, the diameter of the brush hair is preferably 0.5 mm or less from the viewpoint that many deep concave portions are not formed.

The method of adjusting the center line average roughness Ra on the surface of the support after the roughening treatment to _a specific range is that the roughening treatment includes a plurality of treatments, so the conditions for each treatment are generally determined. Although not possible, in the mechanical surface roughening treatment, conditions relating to the roller brush, such as the density of the hair of the roller brush (hereinafter referred to as “brush hair density”) and the number of rotations are roughened. It was found to be effective for adjusting the center line average roughness R _a of the support surface after.

In the present invention, if the density of the hair of the roller brush (hereinafter referred to as “brush hair density”) and the number of rotations are lowered, it is effective to adjust the centerline average roughness Ra to _a specific range. It is.
Specifically, in the present invention, the hair density of the brush is preferably 600 / cm ² or less, more preferably 500 / cm ² or less, and particularly preferably 450 / cm ² or less.
The rotation speed of the roller brush is preferably 300 rpm or less.

A well-known thing can be used for an abrasive | polishing agent. For example, abrasives such as pumicestone, silica sand, aluminum hydroxide, alumina powder, silicon carbide, silicon nitride, volcanic ash, carborundum, and gold sand; a mixture thereof can be used. Of these, pumiston and silica sand are preferable. In particular, silica sand is preferable in that it is harder and less likely to break than pumicestone and is excellent in roughening efficiency, and that it is difficult to form many deep recesses.
The average particle diameter of the abrasive is preferably 3 to 50 μm, and more preferably 6 to 45 μm in terms of excellent surface roughening efficiency and a narrow graining pitch. In particular, it is preferably 30 μm or less for pumicestone and 20 μm or less for silica sand in that many deep recesses are not formed.
For example, the abrasive is suspended in water and used as a slurry. In addition to the abrasive, the slurry liquid may contain a thickener, a dispersant (for example, a surfactant), a preservative, and the like. The specific gravity of the slurry liquid is preferably 0.5-2.

  As an apparatus suitable for the mechanical surface roughening treatment, for example, an apparatus described in Japanese Patent Publication No. 50-40047 can be given.

<Electrochemical roughening treatment>
In the electrochemical surface roughening treatment, an electrolytic solution used for the electrochemical surface roughening treatment using a normal alternating current can be used. Among them, the concavo-convex structure characteristic of the present invention can be formed on the surface by using an electrolytic solution mainly composed of hydrochloric acid or nitric acid.
As the electrolytic surface roughening treatment in the present invention, it is preferable to perform the first and second electrolytic treatments with an alternating waveform current in an acidic solution before and after the cathodic electrolytic treatment. By cathodic electrolysis, hydrogen gas is generated on the surface of the aluminum plate and smut is generated to make the surface state uniform, and it is possible to obtain a uniform electrolytic surface during the subsequent electrolysis with an alternating waveform current. .
This electrolytic surface roughening treatment can be performed according to, for example, an electrochemical grain method (electrolytic grain method) described in Japanese Patent Publication No. 48-28123 and British Patent No. 896,563. This electrolytic grain method uses a sinusoidal alternating current, but it may be performed using a special waveform as described in JP-A-52-58602. Further, the waveform described in JP-A-3-79799 can also be used. JP-A-55-158298, JP-A-56-28898, JP-A-52-58602, JP-A-52-152302, JP-A-54-85802, JP-A-60-190392, JP-A-58-120531, JP-A-63-176187, JP-A-1-5889, JP-A-1-280590, JP-A-1-118489, JP-A-1-148592, and JP-A-1-17896. JP-A-1-188315, JP-A-1-1549797, JP-A-2-235794, JP-A-3-260100, JP-A-3-253600, JP-A-4-72079, JP-A-4-72098, The methods described in JP-A-3-267400 and JP-A-1-141094 can also be applied. In addition to the above, it is also possible to perform electrolysis using an alternating current having a special frequency that has been proposed as a method of manufacturing an electrolytic capacitor. For example, it is described in US Pat. Nos. 4,276,129 and 4,676,879.

Various electrolyzers and power sources have been proposed. U.S. Pat. No. 4,203,637, JP-A-56-123400, JP-A-57-59770, JP-A-53-12738, JP-A-53. -32821, JP-A 53-32822, JP-A 53-32823, JP-A 55-122896, JP-A 55-13284, JP-A 62-127500, JP-A-1-52100 JP-A-1-52098, JP-A-60-67700, JP-A-1-230800, JP-A-3-257199 and the like can be used.
Further, JP-A-52-58602, JP-A-52-152302, JP-A-53-12738, JP-A-53-12739, JP-A-53-32821, JP-A-53-32822, JP 53-32833, JP 53-32824, JP 53-32825, JP 54-85802, JP 55-122896, JP 55-13284, JP 48-28123, JP-B-51-7081, JP-A-52-13338, JP-A-52-133840, JP-A-52-133844, JP-A-52-133845, JP-A-53-149135 And those described in JP-A No. 54-146234 and the like can also be used.

  As an acidic solution which is an electrolytic solution, in addition to nitric acid and hydrochloric acid, U.S. Pat. Nos. 4,671,859, 4,661,219, 4,618,405, 4,600, 482, 4,566,960, 4,566,958, 4,566,959, 4,416,972, 4,374,710, The electrolyte solution described in each specification of 4,336,113 and 4,184,932 can also be used.

  The concentration of the acidic solution is preferably 0.5 to 2.5% by mass, but it is particularly preferably 0.7 to 2.0% by mass in consideration of use in the smut removal treatment. Moreover, it is preferable that liquid temperature is 20-80 degreeC, and it is more preferable that it is 30-60 degreeC.

An aqueous solution mainly composed of hydrochloric acid or nitric acid is an aqueous solution of hydrochloric acid or nitric acid having a concentration of 1 to 100 g / L, such as nitric acid compounds having nitrate ions such as aluminum nitrate, sodium nitrate, ammonium nitrate, or aluminum chloride, sodium chloride, ammonium chloride, etc. At least one hydrochloric acid compound having a hydrochloric acid ion can be added and used in a range from 1 g / L to saturation. Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, a silica, may melt | dissolve in the aqueous solution which has hydrochloric acid or nitric acid as a main component. It is preferable to use a solution obtained by adding aluminum chloride, aluminum nitrate or the like to an aqueous solution of hydrochloric acid or nitric acid having a concentration of 0.5 to 2% by mass so that aluminum ions are 3 to 50 g / L.
Here, “mainly” means that the main component in the aqueous solution is contained in an amount of 30% by mass or more, preferably 50% by mass or more based on the total components added to the aqueous solution. Hereinafter, the same applies to other components.

Further, by adding and using a compound capable of forming a complex with Cu, uniform graining is possible even for an aluminum plate containing a large amount of Cu. Examples of the compound capable of forming a complex with Cu include ammonia; hydrogen atom of ammonia such as methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, cyclohexylamine, triethanolamine, triisopropanolamine, EDTA (ethylenediaminetetraacetic acid), etc. Amines obtained by substituting with a hydrocarbon group (aliphatic, aromatic, etc.); and metal carbonates such as sodium carbonate, potassium carbonate, potassium hydrogencarbonate and the like. In addition, ammonium salts such as ammonium nitrate, ammonium chloride, ammonium sulfate, ammonium phosphate, and ammonium carbonate are also included.
The temperature is preferably 10-60 ° C, more preferably 20-50 ° C.

  The AC power supply wave used for the electrochemical surface roughening treatment is not particularly limited, and a sine wave, a rectangular wave, a trapezoidal wave, a triangular wave or the like is used, but a rectangular wave or a trapezoidal wave is preferable, and a trapezoidal wave is particularly preferable. A trapezoidal wave means what was shown in FIG. In this trapezoidal wave, the time (TP) until the current reaches a peak from zero is preferably 0.2 to 3 msec. If it is less than 0.2 msec, processing irregularities such as chatter marks that occur perpendicular to the traveling direction of the aluminum plate are likely to occur. When TP exceeds 3 msec, especially when a nitric acid electrolyte is used, it is easily affected by trace components in the electrolyte typified by ammonium ions and the like that spontaneously increase by electrolytic treatment, and uniform graining is performed. It becomes hard to be broken. As a result, the stain resistance tends to decrease when a lithographic printing plate is obtained.

A duty ratio of trapezoidal wave alternating current of 1: 2 to 2: 1 can be used. However, as described in Japanese Patent Laid-Open No. 5-195300, in an indirect power feeding method in which no conductor roll is used for aluminum, A duty ratio of 1: 1 is preferable.
A trapezoidal AC frequency of 0.1 to 120 Hz can be used, but 50 to 70 Hz is preferable in terms of equipment. If it is lower than 50 Hz, the carbon electrode of the main electrode is likely to be dissolved, and if it is higher than 70 Hz, it is easily affected by the inductance component on the power supply circuit, and the power supply cost is increased.

  One or more AC power supplies can be connected to the electrolytic cell. As shown in FIG. 3, the current ratio between the AC anode and cathode applied to the aluminum plate facing the main electrode is controlled to achieve uniform graining and to dissolve the carbon of the main electrode. In addition, it is preferable to install an auxiliary anode and divert part of the alternating current. In FIG. 3, 11 is an aluminum plate, 12 is a radial drum roller, 13a and 13b are main poles, 14 is an electrolytic treatment liquid, 15 is an electrolytic solution supply port, and 16 is a slit. , 17 is an electrolyte passage, 18 is an auxiliary anode, 19a and 19b are thyristors, 20 is an AC power source, 40 is a main electrolytic cell, and 50 is an auxiliary anode cell. An anodic reaction that acts on the aluminum plate facing the main electrode by diverting a part of the current value as a direct current to an auxiliary anode provided in a tank separate from the two main electrodes via a rectifier or switching element It is possible to control the ratio between the current value for the current and the current value for the cathode reaction. On the aluminum plate facing the main electrode, the ratio of the amount of electricity involved in the anodic reaction and the cathodic reaction (the amount of electricity at the time of cathode / the amount of electricity at the time of anode) is preferably 0.3 to 0.95.

  As the electrolytic cell, electrolytic cells used for known surface treatments such as a vertical type, a flat type, and a radial type can be used, but a radial type electrolytic cell as described in JP-A-5-195300 is particularly preferable. . The electrolytic solution passing through the electrolytic cell may be parallel to the traveling direction of the aluminum web or may be a counter.

(Nitric acid electrolysis)
Pits having an average opening diameter of 0.5 to 5 μm can be formed by electrochemical surface roughening using an electrolytic solution mainly composed of nitric acid. However, when the amount of electricity is relatively large, the electrolytic reaction is concentrated, and honeycomb pits exceeding 5 μm are also generated.
To obtain such a grain, the total amount of electricity furnished to anode reaction on the aluminum plate up until the electrolysis reaction is completed is preferably from ^{1~1000C / dm 2, 50~300C / dm} 2 It is more preferable that The current density at this time is preferably ²⁰ to 100 A / dm2.
In addition, when a nitric acid electrolyte having a high concentration and / or high temperature is used, a small wave structure having an average opening diameter of 0.2 μm or less can be formed.

If the following pre-electrolysis is performed before the electrolytic surface roughening treatment using the nitric acid electrolytic solution, many deep recesses are not formed in the electrolytic surface roughening treatment.
(Pre-electrolysis)
Pre-electrolysis is a process of forming the starting point of pit formation during nitric acid electrolysis. By performing slight electrolysis using hydrochloric acid that is hardly affected by the material of the aluminum plate and has very high corrosive properties, pits can be formed uniformly on the surface.
In the pre-electrolysis, the hydrochloric acid concentration is preferably 1 to 15 g / L, and the amount of electricity at the anode is preferably 30 to 70 C / m ² .
After pre-electrolysis, it is preferable to perform alkali etching to remove smut. The amount of aluminum dissolved in the alkali etching is preferably 0.2 to 0.6 g / m ² .

(Hydrochloric acid electrolysis)
Since hydrochloric acid has a strong aluminum dissolving power, it is possible to form fine irregularities on the surface with only slight electrolysis. The fine irregularities have an average opening diameter of 0.01 to 0.2 μm and are uniformly generated on the entire surface of the aluminum plate. Such grained total amount of electricity furnished to anode reaction on the aluminum plate up until the electrolysis reaction is completed in order to obtain the, is preferably from 1~100C / dm ^2, in 20~70C / dm ² More preferably. The current density at this time is preferably ²⁰ to 50 A / dm ² .

In such an electrochemical surface roughening treatment with an electrolyte mainly composed of hydrochloric acid, a large crater-like swell is simultaneously formed by increasing the total amount of electricity involved in the anode reaction to 400 to 1000 C / dm ^2. In this case, fine irregularities having an average opening diameter of 0.01 to 0.4 μm are formed on the entire surface by being superimposed on a crater-like wave having an average opening diameter of 10 to 30 μm. Therefore, in this case, since the medium wave structure with an average opening diameter of 0.5 to 5 μm cannot be superimposed, the grain shape of the surface that is a feature of the present invention cannot be made.

The aluminum plate is preferably subjected to cathodic electrolysis during the first and second electrolytic surface-roughening treatments performed in the above-described electrolytic solution such as nitric acid and hydrochloric acid. By this cathodic electrolysis treatment, smut is generated on the surface of the aluminum plate, and hydrogen gas is generated to enable more uniform electrolytic surface roughening treatment. This cathodic electrolysis treatment is carried out in an acidic solution at a cathode electric quantity of preferably 3 to 80 C / dm ² , more preferably 5 to 30 C / dm ² . If the amount of cathodic electricity is less than 3 C / dm ² , the amount of smut adhesion may be insufficient, and if it exceeds 80 C / dm ² , the amount of smut adhesion may be excessive. Further, the electrolytic solution may be the same as or different from the solution used in the first and second electrolytic surface roughening processes.

<Alkaline etching treatment>
The alkali etching treatment is a treatment for dissolving the surface layer by bringing the aluminum plate into contact with an alkali solution.

  Alkaline etching performed before the electrolytic surface roughening treatment removes rolling oil, dirt, natural oxide film, etc. on the surface of the aluminum plate (rolled aluminum) if mechanical surface roughening treatment is not performed. If the surface of the unevenness generated by the mechanical surface roughening treatment is dissolved, the surface with sharp undulations is smoothed. It is done for the purpose of changing.

If you do not mechanical surface-roughening treatment before the alkali etching treatment, the etching amount is preferably from 0.1 to 10 g / m ^2, and more preferably 1 to 5 g / m ^2. If the etching amount is less than 0.1 g / m ² , rolling oil, dirt, natural oxide film, etc. may remain on the surface, so that uniform pits cannot be generated in the subsequent electrolytic surface roughening treatment, resulting in unevenness. May occur. On the other hand, when the etching amount is 1 to 10 g / m ² , the surface rolling oil, dirt, natural oxide film and the like are sufficiently removed. An etching amount exceeding the above range is economically disadvantageous.

When performing mechanical surface-roughening treatment before the alkali etching treatment, the etching amount is preferably from 3 to 20 g / m ^2, and more preferably 5 to 15 g / m ^2. If the etching amount is less than 3 g / m ² , the unevenness formed by mechanical surface roughening may not be smoothed, and uniform pit formation may not be possible in subsequent electrolytic treatment. In addition, the stain may deteriorate during printing. On the other hand, when the etching amount exceeds 20 g / m ² , the concavo-convex structure may disappear.

The alkali etching treatment performed immediately after the electrolytic surface roughening treatment is performed for the purpose of dissolving the smut generated in the acidic electrolytic solution and dissolving the edge portion of the pit formed by the electrolytic surface roughening treatment. .
Since the pits formed by the electrolytic surface roughening treatment are different depending on the type of the electrolytic solution, the optimum etching amount is different, but the etching amount of the alkali etching treatment performed after the electrolytic surface roughening treatment is 0.1 to 5 g / m. ² is preferred. When a nitric acid electrolyte is used, the etching amount needs to be set larger than when a hydrochloric acid electrolyte is used.
When the electrolytic surface roughening treatment is performed a plurality of times, an alkali etching treatment can be performed as necessary after each treatment.

  Examples of the alkali used in the alkaline solution include caustic alkali and alkali metal salts. Specifically, examples of caustic alkali include caustic soda and caustic potash. Examples of the alkali metal salt include alkali metal silicates such as sodium metasilicate, sodium silicate, potassium metasilicate, and potassium silicate; alkali metal carbonates such as sodium carbonate and potassium carbonate; sodium aluminate and alumina. Alkali metal aluminates such as potassium acid; alkali metal aldones such as sodium gluconate and potassium gluconate; dibasic sodium phosphate, dibasic potassium phosphate, tribasic sodium phosphate, tertiary potassium phosphate, etc. An alkali metal hydrogen phosphate is mentioned. Among these, a caustic alkali solution and a solution containing both a caustic alkali and an alkali metal aluminate are preferable from the viewpoint of high etching rate and low cost. In particular, an aqueous solution of caustic soda is preferable.

  Although the density | concentration of an alkaline solution can be determined according to the etching amount, it is preferable that it is 1-50 mass%, and it is more preferable that it is 10-35 mass%. When aluminum ions are dissolved in the alkaline solution, the concentration of aluminum ions is preferably 0.01 to 10% by mass, and more preferably 3 to 8% by mass. The temperature of the alkaline solution is preferably 20 to 90 ° C. The treatment time is preferably 1 to 120 seconds.

  Examples of the method of bringing the aluminum plate into contact with the alkaline solution include, for example, a method in which the aluminum plate is passed through a tank containing the alkaline solution, a method in which the aluminum plate is immersed in a tank containing the alkaline solution, The method of spraying on the surface of a board is mentioned.

<Desmut treatment>
After the electrolytic surface roughening treatment or the alkali etching treatment, pickling (desmut treatment) is performed to remove dirt (smut) remaining on the surface. Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid.
The desmutting treatment is performed, for example, by bringing the aluminum plate into contact with an acidic solution having a concentration of 0.5 to 30% by mass (containing 0.01 to 5% by mass of aluminum ions) such as hydrochloric acid, nitric acid, and sulfuric acid. . Examples of the method of bringing the aluminum plate into contact with the acidic solution include a method in which the aluminum plate is passed through a tank containing the acidic solution, a method in which the aluminum plate is immersed in a tank containing the acidic solution, and the acidic solution being aluminum. The method of spraying on the surface of a board is mentioned.
In the desmutting treatment, the acidic solution is mainly composed of an aqueous solution mainly composed of nitric acid or an aqueous solution mainly composed of hydrochloric acid discharged in the electrolytic surface-roughening treatment described above, or sulfuric acid discharged in an anodic oxidation treatment described later. It is possible to use a waste solution of an aqueous solution.
It is preferable that the liquid temperature of a desmut process is 25-90 degreeC. Moreover, it is preferable that processing time is 1-180 second. Aluminum and aluminum alloy components may be dissolved in the acidic solution used for the desmut treatment.

<Anodizing treatment>
The aluminum plate treated as described above is further subjected to anodizing treatment. The anodizing treatment can be performed by a method conventionally used in this field. In this case, for example, in a solution having a sulfuric acid concentration of 50 to 300 g / L and an aluminum concentration of 5% by mass or less, an anodized film can be formed by energizing an aluminum plate as an anode. As a solution used for the anodizing treatment, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid and the like can be used alone or in combination of two or more.

  Under the present circumstances, the component normally contained at least in an aluminum plate, an electrode, tap water, groundwater, etc. may be contained in electrolyte solution. Furthermore, the 2nd, 3rd component may be added. Examples of the second and third components herein include metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn; Cation such as ammonium ion; anion such as nitrate ion, carbonate ion, chloride ion, phosphate ion, fluoride ion, sulfite ion, titanate ion, silicate ion, borate ion, etc., 0 to 10,000 ppm It may be contained at a concentration of about.

The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. In general, however, the electrolyte concentration is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 0.5. ˜60 A / dm ² , voltage 1 to 100 V, electrolysis time 15 seconds to 50 minutes are appropriate, and the amount of anodic oxide film is adjusted as desired.

  Further, JP-A-54-81133, JP-A-57-47894, JP-A-57-51289, JP-A-57-51290, JP-A-57-54300, JP-A-57-136596, JP-A-58-107498, JP-A-60-200366, JP-A-62-136696, JP-A-63-176494, JP-A-4-17697, JP-A-4-280997, JP-A-6-280997 The methods described in JP-A-207299, JP-A-5-24377, JP-A-5-32083, JP-A-5-125597, JP-A-5-195291 and the like can also be used.

  Of these, as described in JP-A-54-12853 and JP-A-48-45303, it is preferable to use a sulfuric acid solution as the electrolytic solution. The sulfuric acid concentration in the electrolytic solution is preferably 10 to 300 g / L (1 to 30% by mass), and the aluminum ion concentration is 1 to 25 g / L (0.1 to 2.5% by mass). It is preferable that it is 2 to 10 g / L (0.2 to 1% by mass). Such an electrolytic solution can be prepared, for example, by adding aluminum sulfate or the like to dilute sulfuric acid having a sulfuric acid concentration of 50 to 200 g / L.

When anodizing is performed in an electrolytic solution containing sulfuric acid, direct current may be applied between the aluminum plate and the counter electrode, or alternating current may be applied.
When a direct current is applied to the aluminum plate, the current density is preferably from 1 to 60 A / dm ^2, and more preferably 5 to 40 A / dm ^2.
In the case where continuous anodizing treatment is performed, a low current of 5 to 10 A / m ² is initially introduced so that current is concentrated on a part of the aluminum plate and so-called “burning” does not occur. It is preferable to increase the current density to 30 to 50 A / dm ² or more as the current is passed at the density and the anodization process proceeds.
When the anodizing treatment is continuously performed, it is preferable that the anodizing process is performed by a liquid power feeding method in which power is supplied to the aluminum plate through an electrolytic solution.
By performing anodizing treatment under such conditions, a porous film having many pores called micropores can be obtained. Usually, the average pore diameter is about 5 to 50 nm, and the average pore density is 300. ˜800 / μm ² or so.

The amount of the anodized film is preferably 1 to 5 g / m ² . If it is less than 1 g / m ² , the plate tends to be damaged, while if it exceeds 5 g / m ² , a large amount of electric power is required for production, which is economically disadvantageous. The amount of the anodized film is more preferably 1.5 to 4 g / m ² . Moreover, it is preferable to carry out so that the difference in the amount of the anodized film between the center portion of the aluminum plate and the vicinity of the edge portion is 1 g / m ² or less.

As the electrolysis apparatus used for the anodizing treatment, those described in JP-A-48-26638, JP-A-47-18739, JP-B-58-24517, and the like can be used.
Among these, the apparatus shown in FIG. 4 is preferably used. FIG. 4 is a schematic view showing an example of an apparatus for anodizing the surface of an aluminum plate. In the anodizing apparatus 410, the aluminum plate 416 is transported as indicated by arrows in FIG. In the power supply tank 412 in which the electrolytic solution 418 is stored, the aluminum plate 416 is charged to (+) by the power supply electrode 420. The aluminum plate 416 is transported upward by the roller 422 in the power supply tank 412, and the direction is changed downward by the nip roller 424, and then transported toward the electrolytic treatment tank 414 in which the electrolytic solution 426 is stored. The direction is changed horizontally. Next, the aluminum plate 416 is charged to (−) by the electrolytic electrode 430 to form an anodized film on the surface thereof, and the aluminum plate 416 exiting the electrolytic treatment tank 414 is conveyed to a subsequent process. In the anodizing apparatus 410, the roller 422, the nip roller 424, and the roller 428 constitute a direction changing unit, and the aluminum plate 416 is disposed between the power supply tank 412 and the electrolytic treatment tank 414 in the tank 422, 424, and By 428, it is conveyed into a mountain shape and an inverted U shape. The feeding electrode 420 and the electrolytic electrode 430 are connected to a DC power source 434.

  A feature of the anodizing apparatus 410 in FIG. 4 is that the feeding tank 412 and the electrolytic treatment tank 414 are partitioned by a single tank wall 432, and the aluminum plate 416 is conveyed in a mountain shape and an inverted U shape between the tanks. It is in. As a result, the length of the aluminum plate 416 in the inter-tank portion can be minimized. Therefore, the overall length of the anodizing apparatus 410 can be shortened, so that the equipment cost can be reduced. In addition, by conveying the aluminum plate 416 in a mountain shape and an inverted U shape, it is not necessary to form an opening for allowing the aluminum plate 416 to pass through the tank walls of the tanks 412 and 414. Therefore, since the liquid feeding amount required to maintain the liquid level height in each tank 412 and 414 at a required level can be suppressed, the operating cost can be reduced.

<Sealing treatment>
In this invention, you may perform the sealing process which seals the micropore which exists in an anodic oxide film as needed. The sealing treatment can be performed according to a known method such as boiling water treatment, hot water treatment, steam treatment, sodium silicate treatment, nitrite treatment, ammonium acetate treatment and the like. For example, Japanese Patent Publication No. 56-12518, Japanese Patent Application Laid-Open No. 4-4194, Japanese Patent Application No. 4-33952 (Japanese Patent Application Laid-Open No. 5-202496), Japanese Patent Application No. 4-33951 (Japanese Patent Application Laid-Open No. -179482) etc. may be used for sealing treatment.

<Hydrophilic treatment>
A hydrophilization treatment may be performed after the anodizing treatment or the sealing treatment. Examples of the hydrophilization treatment include treatment with potassium fluorozirconate described in US Pat. No. 2,946,638 and phosphomolybdate described in US Pat. No. 3,201,247. Treatment, alkyl titanate treatment described in British Patent 1,108,559, polyacrylic acid treatment described in German Patent 1,091,433, German Patent 1,134, No. 093 and British Patent No. 1,230,447, polyvinylphosphonic acid treatment, Japanese Patent Publication No. 44-6409, phosphonic acid treatment, US Pat. No. 3,307,951 Phytic acid treatment described in the specification of JP, No. 58-16893 and JP-A No. 58-18291 Treatment with a salt of a molecular compound and a divalent metal, as described in US Pat. No. 3,860,426, hydrophilic cellulose (eg, zinc acetate) containing a water-soluble metal salt (eg, zinc acetate) Carboxymethyl cellulose) is provided with a primer layer, and a water-soluble polymer having a sulfo group described in JP-A-59-101651.

Further, phosphates described in JP-A No. 62-019494, water-soluble epoxy compounds described in JP-A No. 62-033692, and JP-A No. 62-097892 Phosphate-modified starch, diamine compounds described in JP-A-63-056498, amino acid inorganic or organic acids described in JP-A-63-130391, JP-A-63-145092 Organic phosphonic acids containing carboxy group or hydroxy group, compounds having amino group and phosphonic acid group described in JP-A-63-165183, and JP-A-2-316290 Specific carboxylic acid derivatives, phosphate esters described in JP-A-3-215095, JP-A-3-261592 Compounds having one amino group and one oxygen acid group of phosphorus described in the publication, phosphoric esters described in JP-A-3-215095, and JP-A-5-246171 Aliphatic or aromatic phosphonic acids such as phenylphosphonic acid, compounds containing S atoms such as thiosalicylic acid described in JP-A-1-307745, and phosphorus described in JP-A-4-282737 Examples of the treatment include undercoating using a compound having a group of oxygen acids.
Further, coloring with an acid dye described in JP-A-60-64352 can also be performed.

  Hydrophilicity can also be achieved by soaking in an aqueous solution of an alkali metal silicate such as sodium silicate or potassium silicate, or by applying a hydrophilic vinyl polymer or hydrophilic compound to form a hydrophilic primer layer. 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.
Examples of the alkali metal silicate include sodium silicate, potassium silicate, and lithium silicate. The aqueous solution of alkali metal silicate may contain an appropriate amount of sodium hydroxide, potassium hydroxide, lithium hydroxide or the like.
The aqueous solution of alkali metal silicate may contain an alkaline earth metal salt or a Group 4 (Group IVA) metal salt. Examples of the alkaline earth metal salt include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; oxalates; Examples of Group 4 (Group IVA) metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, titanium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride. And zirconium tetrachloride. These alkaline earth metal salts and Group 4 (Group IVA) metal salts are used alone or in combination of two or more.

The amount of Si adsorbed by the alkali metal silicate treatment can be measured with a fluorescent X-ray analyzer, and the amount of adsorption is preferably about 1.0 to 15.0 mg / m ² .
By this alkali metal silicate treatment, the effect of improving the dissolution resistance to the alkaline developer on the surface of the lithographic printing plate support is obtained, the dissolution of the aluminum component into the developer is suppressed, and the developer fatigue It is possible to reduce the occurrence of development residue due to the above.

The hydrophilic treatment by forming a hydrophilic undercoat layer can also be performed according to the conditions and procedures described in JP-A Nos. 59-101651 and 60-149491.
Examples of the hydrophilic vinyl polymer used in this method include polyvinyl sulfonic acid, a sulfo group-containing vinyl polymerizable compound such as p-styrene sulfonic acid having a sulfo group, and ordinary vinyl polymerization such as (meth) acrylic acid alkyl ester. And a copolymer with a functional compound. Examples of hydrophilic compounds that may be used in this method include, -NH ₂ group, compounds having at least one selected from the group consisting of -COOH group and sulfo group.

<Washing treatment>
It is preferable to perform water washing after the completion of the above-described processes. For washing, pure water, well water, tap water, or the like can be used. A nip device may be used to prevent the processing liquid from being brought into the next process.

<Aluminum plate (rolled aluminum)>
In order to obtain the lithographic printing plate support of the present invention, a known aluminum plate can be used. The aluminum plate used in the present invention is a metal whose main component is dimensionally stable aluminum, 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 can also be used.

  In the present specification, various substrates made of the above-described aluminum or aluminum alloy are generically used as an aluminum plate. The foreign elements that may be contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium, and the content of the foreign elements in the alloy is 10% by mass or less. It is. Here, the copper content is preferably 0.040% by mass or less in order not to form many deep recesses in the electrolytic surface roughening treatment using the nitric acid electrolytic solution.

  Thus, the composition of the aluminum plate used in the present invention is not specified. For example, a conventionally known material described in the fourth edition of the Aluminum Handbook (1990, published by the Light Metal Association), for example, JIS Al-Mn aluminum plates such as A1050, JIS A1100, JIS A1070, JIS A3004 containing Mn, and internationally registered alloy 3103A can be appropriately used. For the purpose of increasing the tensile strength, an Al—Mg alloy or an Al—Mn—Mg alloy (JIS A3005) in which 0.1% by mass or more of magnesium is added to these aluminum alloys can also be used. Furthermore, an Al—Zr alloy or an Al—Si alloy containing Zr or Si can also be used. Furthermore, an Al—Mg—Si based alloy can also be used.

  Regarding the JIS 1050 material, the techniques proposed by the applicant of the present application are disclosed in Japanese Patent Application Laid-Open Nos. 59-153861, 61-51395, 62-146694, 60-215725, and 60-215725. JP 60-215726, JP 60-215727, JP 60-216728, JP 61-272367, JP 58-11759, JP 58-42493, JP 58- 221254, JP-A-62-148295, JP-A-4-254545, JP-A-4-165541, JP-B-3-68939, JP-A-3-234594, JP-B-1-47545, and JP-A-62. It is described in each publication of -140894. In addition, techniques described in Japanese Patent Publication No. 1-35910 and Japanese Patent Publication No. 55-28874 are also known.

  Regarding the JIS 1070 material, the techniques proposed by the applicant of the present application are disclosed in JP-A-7-81264, JP-A-7-305133, JP-A-8-49034, JP-A-8-73974, JP-A-8-108659 and It is described in JP-A-8-92679.

  Regarding Al-Mg alloys, the techniques proposed by the applicant of the present application are disclosed in Japanese Patent Publication Nos. Sho 62-5080, Sho 63-60823, Shoko 3-61753, JP Sho 60-20396, JP-A-60-203497, JP-B-3-11635, JP-A-61-274993, JP-A-62-23794, JP-A-63-47347, JP-A-63-47348, JP-A-63-47349. JP-A 64-1293, JP-A 63-135294, JP-A 63-87288, JP-B 4-73392, JP-B 7-100844, JP-A 62-149856, JP-B JP-A-4-73394, JP-A-62-181191, JP-B-5-76530, JP-A-63-30294, and JP-B-6-37116. Also described in JP-A-2-215599, JP-A-61-201747, and the like.

  With regard to Al—Mn alloys, techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 60-230951, 1-306288, and 2-293189. In addition, JP-B-54-42284, JP-B-4-19290, JP-B-4-19291, JP-B-4-19292, JP-A-61-35995, JP-A-64-51992, JP-A-4-19592, No. 226394, US Pat. No. 5,009,722, US Pat. No. 5,028,276 and the like.

  With regard to the Al—Mn—Mg alloy, techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 62-86143 and 3-2222796. JP-B 63-60824, JP-A 60-63346, JP-A 60-63347, JP-A-1-293350, European Patent No. 223,737, US Pat. No. 4,818, No. 300, British Patent No. 1,222,777, etc.

  Regarding the Al—Zr alloy, the technique proposed by the applicant of the present application is described in Japanese Patent Publication No. 63-15978 and Japanese Patent Application Laid-Open No. 61-51395. Also described in JP-A-63-143234 and JP-A-63-143235.

  The Al—Mg—Si alloy is described in British Patent 1,421,710.

  As an aluminum plate, the pits generated by the surface roughening treatment can be made uniform, and the average opening diameter of the medium wave structure and the small wave structure generated by the electrochemical surface roughening treatment can be increased. In this respect, Fe is 0.20 to 0.50 mass%, Si is 0.03 to 0.15 mass%, Ti is 0.05 mass% or less, and Cu is 0.040 mass% or less. An aluminum plate that contains Al and inevitable impurities is preferable.

  Hereinafter, the different metal elements contained in the aluminum plate will be described. The essential alloy components in the aluminum plate are Al, Fe and Si, and preferably contain Cu and Ti.

Fe has the effect of increasing the mechanical strength of the aluminum alloy and greatly affects the strength of the support. If the strength is too low, the plate tends to be cut when attached to the plate cylinder of the printing press or during printing. On the other hand, if it is too strong, it will be inferior in fitness when attached to the plate cylinder of a printing press, and will likely cause plate breakage.
The Fe content is preferably 0.20 to 0.50 mass%, more preferably 0.20 to 0.40 mass%.

  Si is an unavoidable compound and may be precipitated as elemental Si by heating during the manufacturing process. If this amount is excessive, the resistance to severe ink stains is lowered, which is not good. On the other hand, in order to eliminate variation in material difference, the content is preferably 0.02% by mass or more. Therefore, the Si content is preferably 0.03 to 0.15 mass%. More preferably, it is 0.04-0.10 mass%.

  Ti is usually contained in an amount of 0.01 to 0.04% by mass as a crystal refining material in order to make the crystal structure at the time of casting finer. If Ti is contained excessively, the resistance of the back oxide film becomes excessive in the electrochemical surface roughening treatment, so that uniform pits may not be formed. Therefore, the range of up to 0.05% by mass of the Ti content is effective. More preferably, it is 0.005-0.03 mass%.

  Cu is a very important element in controlling the electrolytic surface roughening treatment. In the electrolytic surface-roughening treatment, a smut in which the aluminum dissolution reaction (pitting reaction) and the components generated by the dissolution are reattached to the dissolution reaction part by passing an alternating current in an acidic electrolytic solution. Adhesion reactions occur alternately according to an alternating cycle. By repeating this, uniform concave portions (pits) can be formed on the entire surface of the aluminum alloy plate without the concentration of pitting reaction at a specific location. Pit uniformity is essential to obtain good printability.

If the Cu content is less than 0.002% by mass, the resistance of the surface oxide film when forming pits electrochemically becomes too low, and thus uniform pits may not be formed. In this respect, the Cu content is preferably 0.002% by mass or more, and more preferably 0.003% by mass or more.
Further, the present inventors can make the pits having a diameter of 0.5 μm or less generated by electrolytic surface roughening treatment in nitric acid solution by making the Cu content 0.020% by mass or more, and It has been found that the rate of increase of the surface area of the support can be maximized. By increasing the surface area increase ratio, the contact area with the image recording layer can be increased, so that the adhesion is improved, the printing performance is excellent, and the stain resistance when using a lithographic printing plate is further improved. It will be excellent.

On the other hand, if the Cu content exceeds 0.040% by mass, the diameter of the pit generated by the electrolytic surface roughening treatment in the nitric acid solution may become too large and the uniformity of the diameter may be reduced. Is too deep, the solid image portion is poorly deposited, which may affect stain resistance such as ink entanglement. In particular, the stain resistance may be inferior. Therefore, in this invention, it is preferable to make the upper limit of Cu content into 0.040 mass%.
When the Cu content is 0.030% by mass or less, the diameter of the pits generated by the electrolytic surface-roughening treatment in the nitric acid solution can be increased to some extent. A large amount of water can be secured, and the stain resistance is improved.
That is, by increasing the diameter of the pits generated by the electrolytic surface-roughening treatment in nitric acid solution uniformly, both the printing durability and the stain resistance can be improved. 0.040% by mass is preferable, and 0.020 to 0.030% by mass is more preferable.

The balance of the aluminum plate is made of Al and inevitable impurities. Most of inevitable impurities are contained in the Al ingot. If the inevitable impurities are contained in, for example, a metal having an Al purity of 99.7%, the effects of the present invention are not impaired. For inevitable impurities, see, for example, L.A. F. The amount of impurities described in Mondolfo's “Aluminum Alloys: Structure and properties” (1976) and the like may be contained.
Examples of inevitable impurities contained in the aluminum alloy include Mg, Mn, Zn, Cr, and the like, and each of these may be contained in an amount of 0.05% by mass or less. About elements other than these, you may be contained by conventionally well-known content.

  In order to use an aluminum alloy as a plate material, for example, the following method can be employed. First, a molten aluminum alloy adjusted to a predetermined alloy component content is subjected to a cleaning process and cast according to a conventional method. In the cleaning process, in order to remove unnecessary gas such as hydrogen in the molten metal, flux treatment, degassing process using argon gas, chlorine gas, etc., so-called rigid media filter such as ceramic tube filter, ceramic foam filter, A filtering process using a filter that uses alumina flakes, alumina balls or the like as a filter medium, a glass cloth filter, or a combination of a degassing process and a filtering process is performed.

  These cleaning treatments are preferably performed in order to prevent defects caused by foreign matters such as non-metallic inclusions and oxides in the molten metal and defects caused by gas dissolved in the molten metal. Regarding filtering of the molten metal, JP-A-6-57432, JP-A-3-162530, JP-A-5-140659, JP-A-4-231425, JP-A-4-276031, JP-A-5-311261, JP-A-5-311261 6-136466 and the like. Further, the degassing of the molten metal is described in JP-A-5-51659, Japanese Utility Model Laid-Open No. 5-49148, and the like. The applicant of the present application has also proposed a technique relating to degassing of molten metal in Japanese Patent Application Laid-Open No. 7-40017.

Next, casting is performed using the molten metal that has been subjected to the cleaning treatment as described above. As for the casting method, there are a method using a solid mold typified by a DC casting method and a method using a driving mold typified by a continuous casting method.
In DC casting, solidification occurs at a cooling rate of 0.5 to 30 ° C./second. When the temperature is less than 1 ° C., many coarse intermetallic compounds may be formed. When DC casting is performed, an ingot having a thickness of 300 to 800 mm can be manufactured. The ingot is chamfered as necessary according to a conventional method, and usually 1 to 30 mm, preferably 1 to 10 mm of the surface layer is cut. Before and after that, soaking treatment is performed as necessary. When performing a soaking treatment, heat treatment is performed at 450 to 620 ° C. for 1 to 48 hours so that the intermetallic compound does not become coarse. If the heat treatment is shorter than 1 hour, the effect of soaking may be insufficient.

  Then, hot rolling and cold rolling are performed to obtain a rolled aluminum plate. An appropriate starting temperature for hot rolling is 350 to 500 ° C. An intermediate annealing treatment may be performed before or after hot rolling or in the middle thereof. The conditions for the intermediate annealing treatment are heating at 280 to 600 ° C. for 2 to 20 hours, preferably 350 to 500 ° C. for 2 to 10 hours using a batch annealing furnace, or 400 to 600 ° C. using a continuous annealing furnace. Heating is performed for 6 minutes or less, preferably 450 to 550 ° C. for 2 minutes or less. The crystal structure can be made finer by heating at a heating rate of 10 to 200 ° C./second using a continuous annealing furnace.

  The flatness of the aluminum plate finished to a predetermined thickness, for example, 0.1 to 0.5 mm by the above steps may be further improved by a correction device such as a roller leveler or a tension leveler. The flatness may be improved after the aluminum plate is cut into a sheet shape, but in order to improve the productivity, it is preferably performed in a continuous coil state. Further, a slitter line may be used for processing into a predetermined plate width. Moreover, in order to prevent generation | occurrence | production of the damage | wound by friction between aluminum plates, you may provide a thin oil film on the surface of an aluminum plate. As the oil film, a volatile or non-volatile film is appropriately used as necessary.

  On the other hand, as the continuous casting method, a twin roll method (hunter method), a method using a cooling roll typified by the 3C method, a double belt method (Hazley method), a cooling belt or a cooling block typified by Al-Swiss Caster II type The method using is industrially performed. When the continuous casting method is used, it solidifies at a cooling rate of 100 to 1000 ° C./second. Since the continuous casting method generally has a higher cooling rate than the DC casting method, it has a feature that the solid solubility of the alloy component in the aluminum matrix can be increased. Regarding the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-3-79798, JP-A-5-201166, JP-A-5-156414, JP-A-6-262203, and JP-A-6-122949. JP-A-6-210406 and JP-A-6-26308.

  When continuous casting is performed, for example, if a method using a cooling roll such as a Hunter method is used, a cast plate having a thickness of 1 to 10 mm can be directly cast continuously, and the hot rolling step is omitted. The advantage of being able to In addition, when a method using a cooling belt such as the Husley method is used, a cast plate having a thickness of 10 to 50 mm can be cast. Generally, a hot rolling roll is arranged immediately after casting and continuously rolled. Thus, a continuous cast and rolled plate having a thickness of 1 to 10 mm is obtained.

  These continuous cast and rolled plates are subjected to processes such as cold rolling, intermediate annealing, improvement of flatness, slits, and the like in the same manner as described for DC casting. Finished to a thickness of 5 mm. Regarding the intermediate annealing condition and the cold rolling condition when using the continuous casting method, the techniques proposed by the applicant of the present application are disclosed in JP-A-6-220593, JP-A-6-210308, JP-A-7-54111, It is described in JP-A-8-92709.

Various characteristics described below are desired for the aluminum plate thus manufactured.
As for the strength of the aluminum plate, it is preferable that the 0.2% proof stress is 140 MPa or more in order to obtain the stiffness required for a lithographic printing plate support. Further, in order to obtain a certain level of waist strength even when performing the burning treatment, the 0.2% yield strength after heat treatment at 270 ° C. for 3 to 10 minutes is preferably 80 MPa or more, and 100 MPa or more. It is more preferable that In particular, when the waist strength is required for an aluminum plate, an aluminum material added with Mg or Mn can be used, but if the waist is strengthened, the ease of fitting to the plate cylinder of a printing press becomes inferior. Depending on the application, the material and the amount of trace components added are appropriately selected. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Application Laid-Open Nos. 7-126820 and 62-140894.

  The crystal structure of the aluminum plate may cause poor surface quality when the surface of the aluminum plate is subjected to chemical or electrochemical surface roughening. It is preferably not too coarse. The crystal structure on the surface of the aluminum plate preferably has a width of 200 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, and the length of the crystal structure is 5000 μm or less. Is preferably 1000 μm or less, and more preferably 500 μm or less. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 6-218495, 7-39906, and 7-124609.

  The alloy component distribution of the aluminum plate, when chemical surface roughening treatment or electrochemical surface roughening treatment is performed, poor surface quality occurs due to non-uniform distribution of the alloy component on the surface of the aluminum plate. Therefore, it is preferable that the surface is not very uneven. With regard to these, the techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 6-48058, 5-301478, and 7-132689.

  In the intermetallic compound of the aluminum plate, the size and density of the intermetallic compound may affect the chemical roughening treatment or the electrochemical roughening treatment. With regard to these, techniques proposed by the applicant of the present application are described in Japanese Patent Laid-Open Nos. 7-138687 and 4-254545.

  In the present invention, an aluminum plate as shown above can be used with unevenness by lamination rolling, transfer or the like in the final rolling step.

The aluminum plate used in the present invention is a continuous belt-like sheet material or plate material. That is, it may be an aluminum web or a sheet-like sheet cut to a size corresponding to a planographic printing plate precursor shipped as a product.
Since scratches on the surface of the aluminum plate may become defects when processed into a lithographic printing plate support, it is possible to generate scratches at the stage prior to the surface treatment process for making a lithographic printing plate support It is necessary to suppress as much as possible. For that purpose, it is preferable that the package has a stable form and is hardly damaged during transportation.
In the case of an aluminum web, for example, the packaging of aluminum is, for example, laying a hardboard and felt on an iron pallet, applying cardboard donut plates to both ends of the product, wrapping the whole with a polytube, and inserting a wooden donut into the inner diameter of the coil Then, a felt is applied to the outer periphery of the coil, the band iron is used to squeeze it, and the display is performed on the outer periphery. Moreover, a polyethylene film can be used as the packaging material, and needle felt and hard board can be used as the cushioning material. There are various other forms, but the present invention is not limited to this method as long as it is stable and can be transported without being damaged.

  The thickness of the aluminum plate used in the present invention is about 0.1 to 0.6 mm, preferably 0.15 to 0.4 mm, and more preferably 0.2 to 0.3 mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, the user's desires, and the like.

[Lithographic printing plate precursor]
Next, the planographic printing plate precursor of the present invention will be described. The lithographic printing plate precursor according to the invention comprises an image recording layer provided on the lithographic printing plate support according to the invention.

<Undercoat layer>
In the lithographic printing plate precursor according to the present invention, before providing an image recording layer on the lithographic printing plate support of the present invention obtained as described above, if necessary, for example, zinc borate or the like. An inorganic undercoat layer such as a water-soluble metal salt or an organic undercoat layer may be provided.

  Examples of the organic compound used in the organic undercoat layer include carboxymethyl cellulose; dextrin; gum arabic; polymers and copolymers having a sulfonic acid group in the side chain; polyacrylic acid; amino such as 2-aminoethylphosphonic acid Phosphonic acids having a group; phenylphosphonic acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid, ethylenediphosphonic acid, etc., which may have a substituent; Organic phosphoric acid such as phenylphosphonic acid, naphthylphosphoric acid, alkylphosphoric acid, glycerophosphoric acid, which may be substituted; phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid, glycerophosphinic acid, etc., which may have a substituent Organic phosphinic acids; amino acids such as glycine and β-alanine Amine hydrochloride having hydroxy group such as triethanolamine hydrochloride; and the yellow dye. These may be used alone or in combination of two or more.

The organic undercoat layer is provided by applying a solution obtained by dissolving the above organic compound in water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof on an aluminum plate and drying it. The concentration of the solution in which the organic compound is dissolved is preferably 0.005 to 10% by mass. The coating method is not particularly limited, and any method such as bar coater coating, spin coating, spray coating, and curtain coating can be used.
The coverage of the organic undercoat layer after drying is preferably ² to 200 mg / m ² , and more preferably 5 to 100 mg / m ² . When it is in the above range, the printing durability becomes better.

<Image recording layer>
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. Suitable examples of the image recording layer include a conventional positive type, a conventional negative type, a photopolymer type, a thermal positive type, a thermal negative type, and an unprocessable type that can be developed on the machine. Hereinafter, these suitable image recording layers will be described.

<Conventional positive type>
Examples of the photosensitive resin composition suitably used in the conventional positive type photosensitive layer include an o-quinonediazide compound and a water-insoluble and alkali-soluble polymer compound (hereinafter referred to as “alkali-soluble polymer compound”). The composition to contain is mentioned.
Examples of o-quinonediazide compounds include esters of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and phenol-formaldehyde resin or cresol-formaldehyde resin, and US Pat. No. 3,635,709. Examples include esters of 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride and pyrogallol / acetone resin as described.
Examples of the alkali-soluble polymer compound include phenol / formaldehyde resin, cresol / formaldehyde resin, phenol / cresol / formaldehyde co-condensation resin, polyhydroxystyrene, N- (4-hydroxyphenyl) methacrylamide copolymer, Carboxy group-containing polymers described in JP-A-7-36184, acrylic resins containing phenolic hydroxy groups as described in JP-A-51-34711, and JP-A-2-866. Examples thereof include acrylic resins having a sulfonamide group and urethane resins.

  Further, in the photosensitive resin composition, compounds such as a sensitivity adjusting agent, a baking agent, and a dye described in [0024] to [0027] of JP-A-7-92660 and [0031] of the same publication. It is preferable to add a surfactant for improving the coating property.

<Conventional negative type>
Examples of the photosensitive resin composition suitably used for the conventional negative type photosensitive layer include a composition containing a diazo resin and an alkali-soluble or swellable polymer compound (hereinafter referred to as “binder”).
Examples of the diazo resin include a condensate of an aromatic diazonium salt and an active carbonyl group-containing compound such as formaldehyde, a condensate of p-diazophenylamines and formaldehyde, and a hexafluorophosphate or a tetrafluoroborate. Organic solvent-soluble diazo resin inorganic salts which are reaction products of In particular, a high molecular weight diazo compound containing 20 mol% or more of a hexamer described in JP-A-59-78340 is preferable.

Suitable binders include, for example, a copolymer containing acrylic acid, methacrylic acid, crotonic acid or maleic acid as an essential component, specifically 2 as described in JP-A-50-118802. -Multi-component copolymers of monomers such as hydroxyethyl (meth) acrylate, (meth) acrylonitrile, (meth) acrylic acid, alkyl acrylates as described in JP-A-56-4144, (meth) acrylonitrile And multi-component copolymers composed of unsaturated carboxylic acids.
Furthermore, plastics for imparting flexibility and abrasion resistance to the photosensitive resin composition described in JP-A-7-281425, [0014] to [0015]. It is preferable to add a compound such as an agent and a development accelerator and a surfactant for improving the coating property.
As an undercoat layer of the conventional positive or negative photosensitive layer, a polymer having a component having an acid group and a component having an onium group as described in JP-A-2000-105462. An intermediate layer containing the compound is preferably provided.

<Photopolymer type>
A photopolymerization type photosensitive composition (hereinafter referred to as “photopolymerizable composition”) suitably used for a photopolymer type photosensitive layer is an addition-polymerizable ethylenically unsaturated bond-containing compound (hereinafter simply referred to as “ethylene”). ), A photopolymerization initiator, and a polymer binder as essential components, and if necessary, various compounds such as a colorant, a plasticizer, and a thermal polymerization inhibitor. Containing.
The ethylenically unsaturated bond-containing compound contained in the photopolymerizable composition is such that, when the photopolymerizable composition is irradiated with actinic rays, it undergoes addition polymerization by the action of the photopolymerization initiator, and is crosslinked and cured. It is a compound having an ethylenically unsaturated bond. The ethylenically unsaturated bond-containing compound can be arbitrarily selected from compounds having at least one terminal ethylenically unsaturated bond, preferably two or more, such as monomers, prepolymers (ie, dimers). Trimers and oligomers), mixtures thereof, and copolymers thereof. Examples of monomers include esters of unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid) and aliphatic polyhydric alcohol compounds, unsaturated carboxylic acids and aliphatic polyhydric compounds. And amides with a polyvalent amine compound. Urethane addition polymerizable compounds are also suitable.

As the photopolymerization initiator contained in the photopolymerizable composition, various photopolymerization initiators or a combination system (photoinitiation system) of two or more photopolymerization initiators are appropriately selected depending on the wavelength of the light source used. For example, an initiation system described in JP-A-2001-22079, [0021] to [0023] is preferable.
The polymer binder contained in the photopolymerizable composition not only functions as a film-forming agent for the photopolymerizable composition, but also needs to dissolve the photosensitive layer in an alkali developer. An organic high molecular weight polymer that is swellable is used. As the polymer binder, those described in [0036] to [0063] of the same publication are useful.
It is preferable to add an additive (for example, a surfactant for improving coating properties) described in [0079] to [0088] of the same publication to the photopolymerizable composition.
Further, it is preferable to provide an oxygen-blocking protective layer on the photosensitive layer in order to prevent the oxygen polymerization inhibiting action. Examples of the polymer contained in the oxygen barrier protective layer include polyvinyl alcohol and copolymers thereof.
Furthermore, it is also preferable to provide an adhesive layer as described in [0131] to [0165] of JP-A-2001-228608 as the undercoat layer of the photosensitive layer.

<Thermal positive type>
The thermal positive type heat-sensitive layer contains an alkali-soluble polymer compound and a photothermal conversion substance.
Alkali-soluble polymer compounds include homopolymers containing acidic groups in the polymer, copolymers thereof, and mixtures thereof, in particular, (1) phenolic hydroxy groups (—Ar—OH), (2) Those having an acidic group such as a sulfonamide group (—SO ₂ NH—R) are preferred from the viewpoint of solubility in an alkali developer. In particular, it is preferable to have a phenolic hydroxy group from the viewpoint of excellent image formability upon exposure with an infrared laser or the like. For example, phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (any of m-, p- and m- / p-mixed) mixed Preferred are novolak resins such as formaldehyde resin; pyrogallol acetone resin. More specifically, the polymers described in JP-A-2001-305722, [0023] to [0042] are preferably used.

The photothermal conversion substance converts exposure energy into heat and can efficiently cancel the interaction of the exposed area of the heat sensitive layer. From the viewpoint of recording sensitivity, a pigment or dye having a light absorption region in the infrared region with a wavelength of 700 to 1200 nm is preferable. Specific examples of the dye include 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 thiolates. Complex (for example, nickel thiolate complex) etc. are mentioned. Among these, cyanine dyes are preferable, and examples thereof include cyanine dyes represented by general formula (I) in JP-A No. 2001-305722.
In the composition used for the thermal positive type heat-sensitive layer, the same sensitivity control agent, bake-out agent, dye, etc. as those described in the conventional positive type and a surfactant for improving the coating property are added. It is preferable to add. Specifically, the compounds described in JP-A-2001-305722, [0053] to [0059] are preferable.

Further, the thermal positive type image recording layer is not limited to a single layer but may have a two-layer structure (for example, a two-layer structure as described in JP-A-11-218914).
As an image recording layer having a two-layer structure (multilayer image recording layer), a lower layer (hereinafter referred to as “A layer”) having excellent printing durability and solvent resistance is provided on the side close to the support, and a positive layer is provided thereon. A type provided with a layer having excellent image formability (hereinafter referred to as “B layer”) is preferable. This type has high sensitivity and can realize a wide development latitude. The B layer generally contains a photothermal conversion substance. Preferred examples of the photothermal conversion substance include the dyes described above.
As the resin used for the A layer, a polymer having a monomer having a sulfonamide group, an active imino group, a phenolic hydroxy group or the like as a copolymerization component is preferably used because it has excellent printing durability and solvent resistance. . As the resin used for the B layer, an alkaline aqueous solution-soluble resin having a phenolic hydroxy group is preferably exemplified.
In addition to the resin, the composition used for the A layer and the B layer can contain various additives as necessary. Specifically, various additives as described in [0062] to [0085] of JP-A-2002-3233769 are preferably used. Further, the additives described in [0053] to [0060] of JP-A-2001-305722 described above are also preferably used.
About each component which comprises A layer and B layer, and its content, it is preferable to make it describe in Unexamined-Japanese-Patent No. 11-218914.

  An undercoat layer is preferably provided between the thermal positive type heat-sensitive layer and the support. Examples of components contained in the undercoat layer include various organic compounds described in JP-A-2001-305722, [0068].

<Thermal negative type>
The thermal negative-type heat-sensitive layer is a negative-type heat-sensitive layer in which the infrared laser irradiation part is cured to form an image part.
A preferred example of such a thermal negative type heat-sensitive layer is a polymerization type layer (polymerization layer). The polymerization layer comprises (A) an infrared absorber, (B) a radical generator (radical polymerization initiator), a curing reaction caused by the generated radical (C) a radical polymerizable compound, and (D) a binder. Containing polymer.
In the polymerization layer, the infrared rays absorbed by the infrared absorber are converted into heat, and the generated heat decomposes radical polymerization initiators such as onium salts to generate radicals. The radically polymerizable compound is selected from compounds having a terminal ethylenically unsaturated bond, and a polymerization reaction is caused in a chain by the generated radicals and is cured.

  Examples of (A) infrared absorbers include the above-described photothermal conversion substances contained in the above-described thermal positive type heat-sensitive layer. In particular, specific examples of cyanine dyes are disclosed in JP-A No. 2001-133969. To [0019], and (B) radical generators include onium salts. Specific examples of onium salts that can be suitably used include those described in JP-A-2001-133969. The compounds described in [0030] to [0033] are mentioned, and the (C) radical polymerizable compound is selected from compounds having at least one terminal ethylenically unsaturated bond, preferably two or more. (D) It is preferable to use a linear organic polymer as the binder polymer, and a linear organic polymer that is soluble or swellable in water or weak alkaline water is selected. Of these, a (meth) acrylic resin having a benzyl group or an allyl group and a carboxy group in the side chain is particularly preferable because of its excellent balance of film strength, sensitivity, and developability. Regarding (C) the radical polymerizable compound and (D) the binder polymer, those described in detail in [0036] to [0060] of the same publication can be used. As other additives, it is also preferable to add additives described in [0061] to [0068] of the same publication (for example, a surfactant for improving coating properties).

  In addition to the polymerization type, an acid cross-linked layer (acid cross-linked layer) is preferably used as one of the thermal negative type heat-sensitive layers. The acid cross-linking layer includes (E) a compound that generates an acid by light or heat (hereinafter referred to as “acid generator”) and (F) a compound that cross-links by the generated acid (hereinafter referred to as “cross-linking agent”). And (G) an alkali-soluble polymer compound that can react with a crosslinking agent in the presence of an acid. In order to efficiently use the energy of the infrared laser, (A) an infrared absorber is blended in the acid crosslinking layer. Examples of the acid generator (E) include compounds capable of generating an acid upon thermal decomposition, such as a photoinitiator for photopolymerization, a photochromic agent for dyes, and an acid generator used for a microresist. . (F) As the crosslinking agent, (i) an aromatic compound substituted with a hydroxymethyl group or an alkoxymethyl group, (ii) a compound having an N-hydroxymethyl group, an N-alkoxymethyl group or an N-acyloxymethyl group, (Iii) An epoxy compound is mentioned. (G) Examples of the alkali-soluble polymer compound include novolak resins and polymers having a hydroxyaryl group in the side chain.

<Non-treatment type>
The untreated type heat-sensitive layer includes types such as a thermoplastic fine particle polymer type, a microcapsule type, and a sulfonic acid generating polymer-containing type.
In the thermoplastic fine particle polymer type, (H) hydrophobic hot-melt resin fine particles are dispersed in (J) a hydrophilic polymer matrix, and the hydrophobic polymer is melted by the heat of the exposed area and fused to each other. To form a hydrophobic region, that is, an image portion.
(H) Hydrophobic heat-meltable resin fine particles (hereinafter referred to as “fine-particle polymer”) are preferably those in which the fine-particle polymers are melted and coalesced by heat. Dispersed particulate polymers having a hydrophilic surface are preferred. As the fine particle polymer, Research Disclosure No. 33303 (January 1992), JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250, and European Patent Application Publication No. 931,647. Preferred examples thereof include thermoplastic fine particle polymers. Specific examples include homopolymers or copolymers of monomers such as ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, or mixtures thereof. . Of these, polystyrene and polymethyl methacrylate are preferably used. The fine particle polymer having a hydrophilic surface is such that the polymer itself constituting the fine particle is hydrophilic, or the polymer itself is hydrophilic, such as those obtained by introducing a hydrophilic group into the main chain or side chain of the polymer. A hydrophilic polymer such as polyvinyl alcohol or polyethylene glycol, a hydrophilic oligomer or a hydrophilic low molecular weight compound is adsorbed on the surface of the fine particle polymer to make the surface hydrophilic. As the fine particle polymer, a fine particle polymer having a thermally reactive functional group is more preferable. When the fine particle polymer as described above is dispersed in the (J) hydrophilic polymer matrix, the on-press development property is improved when the on-press development is performed, and the film strength of the thermosensitive layer itself is also improved.

Examples of the microcapsule type include a type described in JP-A No. 2000-118160 and a microcapsule type containing a compound having a thermally reactive functional group as described in JP-A No. 2001-277740. Preferably mentioned.
Examples of the sulfonic acid generating polymer used in the sulfonic acid generating polymer-containing type include, for example, a sulfonic acid ester group, a disulfone group, or a sec- or tert-sulfonamide group described in JP-A-10-282672 as a side chain. The polymer which has is mentioned.
By including a hydrophilic resin in the untreated type heat-sensitive layer, not only the on-press developability is improved, but also the film strength of the heat-sensitive layer itself is improved. In addition, a lithographic printing plate precursor that does not require development processing can be obtained by crosslinking and curing the hydrophilic resin. Examples of the hydrophilic resin include those having a hydrophilic group such as hydroxy group, carboxy group, hydroxyethyl group, hydroxypropyl group, amino group, aminoethyl group, aminopropyl group, carboxymethyl group, and hydrophilic sol-gel conversion. A system binder resin is preferred. Specific examples of the hydrophilic resin include those listed as the hydrophilic resin used as the above-mentioned (J) hydrophilic polymer matrix.
Among these, a sol-gel conversion binder resin is preferable.
It is necessary to add a photothermal conversion substance to the untreated type heat-sensitive layer. The photothermal conversion substance only needs to be a substance that absorbs light having a wavelength of 700 nm or more, and a dye similar to the dye used for the above-described thermal positive type is particularly preferable.

<Back coat layer>
Thus, the image recording layer in the case where the lithographic printing plate is overlaid on the back surface of the lithographic printing plate precursor obtained by providing various image recording layers on the lithographic printing plate support, if necessary. In order to prevent scratching, a backcoat layer made of an organic polymer compound can be provided.

<Application method>
As a method for applying the conventional type, photopolymer type, thermal type, and non-processing type image recording layer forming liquid to the roughened surface of the lithographic printing plate support, a method using a coating rod, an extrusion type Conventionally known methods such as a method using a coater and a method using a slide bead coater can be used, and can be performed according to known conditions.

  As an apparatus for drying the aluminum plate after coating the conventional type, photopolymer type, thermal type, and non-process type image recording layer forming liquid, there is a pass roll in the drying apparatus described in JP-A-6-63487. An arch dryer that is dried while being conveyed by the pass roll, an air dryer that is dried by supplying air from above and below by a nozzle, and a web is floated, a radiant heat dryer that is dried by radiant heat from a medium heated to a high temperature, In addition, there is a roller dryer or the like that heats the roller and dries by conduction heat transfer by contact with the roller.

[Lithographic printing plate]
The lithographic printing plate precursor according to the invention is made into a lithographic printing plate by various processing methods according to the image recording layer.
In general, image exposure is performed. Examples of the active light source used for image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, and a chemical lamp. Examples of the laser beam include a helium-neon laser (He-Ne laser), an argon laser, a krypton laser, a helium-cadmium laser, a KrF excimer laser, a semiconductor laser, a YAG laser, and a YAG-SHG laser.
After the exposure, when the image recording layer is any one of a thermal type, a conventional type, and a photopolymer type, it is preferable to develop with a developer and obtain a lithographic printing plate after the exposure. The preferred developer used for the lithographic printing plate precursor is not particularly limited as long as it is an alkaline developer, but an alkaline aqueous solution substantially not containing an organic solvent is preferred. Moreover, it can also develop using the developing solution which does not contain alkali metal silicate substantially. The method of developing using a developer substantially free of alkali metal silicate is described in detail in JP-A-11-109637, and the contents described in the publication can be used. . Moreover, the lithographic printing plate precursor can be developed using a developer containing an alkali metal silicate.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
1. Preparation of lithographic printing plate support ( Reference Example 1)
<Aluminum plate I>
Si: 0.06 mass%, Fe: 0.30 mass%, Cu: 0.005 mass%, Mn: 0.001 mass%, Mg: 0.001 mass%, Zn: 0.001 mass%, Ti: It contains 0.03% by mass, and the balance is prepared using Al and an inevitable impurity aluminum alloy. After the molten metal treatment and filtration, an ingot having a thickness of 500 mm and a width of 1200 mm is obtained by a DC casting method. Created. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, the temperature was kept constant at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Furthermore, after performing heat processing using a continuous annealing machine at 500 degreeC, it finished by cold rolling to 0.24 mm in thickness, and obtained the aluminum plate I which belongs to the component range of JIS1050 material. After making this aluminum plate I width 1030mm, it used for the surface treatment shown below.

<Surface treatment>
The surface treatment was performed by continuously performing the following various treatments (a) to (j). In addition, after each process and water washing, the liquid was drained with the nip roller.

(A) Mechanical surface roughening treatment Using an apparatus as shown in FIG. 1, a slurry of a polishing agent (pumice, average particle size 30 μm) and water (specific gravity 1.12) is used as a polishing slurry liquid to make aluminum. While being supplied to the surface of the plate 1, a mechanical surface roughening treatment was performed by a rotating roller-shaped nylon brush. In FIG. 1, 1 is an aluminum plate, 2 and 4 are roller brushes, 3 is a polishing slurry, and 5, 6, 7 and 8 are support rollers. The average particle size of the abrasive was 30 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.48 mm. The nylon brush was planted so as to be dense by making holes in a stainless steel tube having a diameter of 300 mm (the brush hair density was 450 / cm ² ). Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum plate I obtained above was subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 26 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C. m ^{2 was} dissolved. Then, water washing by spraying was performed.

(C) Desmutting treatment Desmutting treatment was performed by spraying with a 1% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions) at a liquid temperature of 50 ° C. The AC power supply waveform is the waveform shown in FIG. 2. The time TP until the current value reaches a peak from zero is 0.8 msec, the duty ratio is 1: 1, a 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. 3 was used.
The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Then, water washing by spraying was performed.

(E) Alkaline etching treatment An aluminum plate was subjected to an etching treatment at 32 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass%, and the aluminum plate was dissolved at 0.25 g / m ² . Removes the smut component mainly composed of aluminum hydroxide that was generated when electrochemical roughening treatment was performed using the alternating current of the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(F) Desmut treatment Desmut treatment by spraying was performed with a 15% by weight aqueous solution of sulfuric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / L aqueous solution (containing 5 g / L of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform is the waveform shown in FIG. 2, the time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, a 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. 3 was used.
The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode.
Then, water washing by spraying was performed.

(H) Alkaline etching treatment An aluminum plate was subjected to an etching treatment at 32 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass%, and the aluminum plate was dissolved at 0.10 g / m ² . Removes the smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening treatment was performed using alternating current in the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(I) Desmutting treatment A desmutting treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(J) Anodizing treatment Anodizing treatment was performed using an anodizing apparatus having the structure shown in FIG. 4 to obtain a lithographic printing plate support of Reference Example 1.
Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 170 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 38 ° C. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .

(Example 2 and Example 3)
In the above (a) mechanical roughening treatment, the lithographic printing plate supports of Examples 2 and 3 were prepared in the same manner as in Reference Example 1 except that the average particle size of the abrasive was 25 μm and 20 μm, respectively. Got the body.

(Example 4)
Reference Example 1 except that the average particle size of the abrasive was set to 20 μm in (a) mechanical surface roughening treatment, and the dissolution amount of the aluminum plate was set to 1 g / m ² in (h) alkali etching treatment. By the same method, a lithographic printing plate support of Example 4 was obtained.

(Example 5)
<Aluminum plate II>
Si: 0.06 mass%, Fe: 0.30 mass%, Cu: 0.023 mass%, Mn: 0.001 mass%, Mg: 0.001 mass%, Zn: 0.001 mass%, Ti: In the same manner as the aluminum plate I, an aluminum plate II belonging to the component range of the JIS 1050 material was obtained by using 0.03% by mass and the balance being aluminum and an aluminum alloy of inevitable impurities. This aluminum plate II was 1030 mm wide.
Using this aluminum plate II, surface treatment was performed in the same manner as in Reference Example 1 to obtain a lithographic printing plate support of Example 5.

(Example 6)
Using the aluminum plate II, surface treatment was performed in the same manner as in Example 2 to obtain a lithographic printing plate support of Example 6.

(Example 7)
Using the aluminum plate II, surface treatment was performed in the same manner as in Example 3 to obtain a lithographic printing plate support of Example 7.

(Comparative Example 1)
A lithographic printing plate support of Comparative Example 1 was obtained in the same manner as in Reference Example 1 except that (g), (h) and (i) were not performed.

(Comparative Example 2)
The same method as in Reference Example 1 except that (g), (h) and (i) are not carried out, and the average particle size of the abrasive is 25 μm in the mechanical surface roughening treatment (a). Thus, a lithographic printing plate support of Comparative Example 2 was obtained.

(Comparative Example 3)
The same method as in Reference Example 1 except that (d), (e) and (f) are not performed, and the average particle size of the abrasive is 25 μm in the mechanical surface roughening treatment (a). Thus, a lithographic printing plate support of Comparative Example 3 was obtained.

(Comparative Example 4)
The same method as in Reference Example 1 except that (d), (e) and (f) are not performed, and the average particle size of the abrasive is 20 μm in the mechanical surface roughening treatment (a). Thus, a lithographic printing plate support of Comparative Example 4 was obtained.

(Comparative Example 5)
A lithographic printing plate support of Comparative Example 5 was obtained in the same manner as in Reference Example 1 except that in the above (a) mechanical roughening treatment, the average particle size of the abrasive was 50 μm.

(Comparative Example 6)
The same method as in Reference Example 1 except that (g), (h) and (i) are not carried out, and the average grain size of the abrasive is 50 μm in the mechanical surface roughening treatment (a). Thus, a lithographic printing plate support of Comparative Example 6 was obtained.

(Comparative Example 7)
A lithographic printing plate support of Comparative Example 7 was obtained in the same manner as in Reference Example 1 except that (a), (g), (h) and (i) were not performed.

(Comparative Example 8)
A lithographic printing plate support of Comparative Example 8 was obtained in the same manner as in Reference Example 1 except that in the above (a) mechanical surface roughening treatment, the hair density of the brush was changed to 700 / cm ² .

(Comparative Example 9)
Using the aluminum plate II, surface treatment was performed in the same manner as in Comparative Example 1 to obtain a lithographic printing plate support of Comparative Example 9.

(Comparative Example 10)
Using the aluminum plate II, surface treatment was performed in the same manner as in Comparative Example 2 to obtain a lithographic printing plate support of Comparative Example 10.

(Comparative Example 11)
Using the aluminum plate II, surface treatment was performed in the same manner as in Comparative Example 3 to obtain a lithographic printing plate support of Comparative Example 11.

(Comparative Example 12)
Using the aluminum plate II, surface treatment was performed in the same manner as in Comparative Example 5 to obtain a lithographic printing plate support of Comparative Example 12.

2. Measurement of surface shape of lithographic printing plate support The following measurements (1) to (7) were performed on the concave portions on the surface of the lithographic printing plate support obtained above.
The results are shown in Tables 1 and 2. In Table 2, “-” indicates that there was no concave portion of the corresponding wavelength.

(1) Centerline average roughness _Ra
Two-dimensional roughness measurement is performed with a stylus type roughness meter (SUFCOM 575, manufactured by Tokyo Seimitsu Co., Ltd.), the average roughness specified in ISO 4287 is measured five times, and the average value is calculated as the centerline average roughness _Ra . did.
The conditions for the two-dimensional roughness measurement were a cut-off value of 0.8 mm, a tilt correction FLAT-ML, a measurement length of 3 mm, a vertical magnification of 10000 times, a scanning speed of 0.3 mm / sec, and a stylus tip diameter of 2 μm.

(2) Average wavelength of large wave structure Two-dimensional roughness measurement is performed with a stylus type roughness meter (SUFCOM 575, manufactured by Tokyo Seimitsu Co., Ltd.), and the average mountain spacing S _m defined in ISO 4287 is measured five times. The value was taken as the average wavelength. Two-dimensional roughness measurement was performed under the following conditions.
cut off 0.8, tilt correction FLAT-ML, measurement length 3 mm, longitudinal magnification 10000 times, scanning speed 0.3 mm / sec, stylus tip diameter 2 μm

(3) Medium Wave Structure Average Aperture Diameter The surface of the support was photographed using a SEM at a magnification of 2000 times from directly above. 50 medium pits) were extracted, and the diameter was read to obtain the opening diameter, and the average opening diameter was calculated.

(4) Average aperture diameter of small wave structure The surface of the support was photographed at a magnification of 50000 times from directly above using a high resolution SEM, and 50 small wave structure pits (small wave pits) were extracted from the obtained SEM photograph. The diameter was read and used as the opening diameter, and the average opening diameter was calculated.

(5) Average of the ratio of the depth to the aperture diameter of the wavelet structure The average of the ratio of the depth to the aperture diameter of the wavelet structure is obtained by photographing the fracture surface of the support at a magnification of 50000 times using a high-resolution SEM. In the SEM photograph, 20 small wave pits having an opening diameter of 0.3 μm or less were extracted, the opening diameter and the depth were read, the ratio was obtained, and the average value was calculated.

(6) Number of recesses with a depth of 3 μm or more Using a laser microscope (Micromap 520, manufactured by Ryoka System Co., Ltd.), surface 400 μm □ is scanned in a non-contact manner at a 0.01 μm pitch to obtain three-dimensional data. In the three-dimensional data, the number of recesses having a depth of 3 μm or more was counted, and the number per 1 mm ² was calculated. In Tables 1 and 2, the number of recesses per 1 mm ² is indicated as “the number of recesses is 3 μm or less”. As the laser microscope, in addition to the one used above, for example, an ultra-deep shape measuring microscope VK5800 manufactured by KEYENCE can be used in the same manner.

(7) counts the number of depth 4μm or more recesses in the three-dimensional data obtained in the same manner as the number of the number (6) the depth 3μm or more recesses of a depth 4μm or more recesses, the number per 1 mm ² Was calculated. In Tables 1 and 2, the number of recesses per 1 mm ² is indicated as “the number of recesses is 4 μm or less”.

3. Preparation of lithographic printing plate precursor A lithographic printing plate precursor was obtained by providing a thermal positive type image recording layer on each of the lithographic printing plate supports obtained above. Before providing the image recording layer, a hydrophilic treatment by an alkali metal silicate treatment was performed as described later.

The lithographic printing plate support obtained above is immersed in a treatment tank of a 1% by weight aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C. for 10 seconds, whereby alkali metal silicate treatment (silicate treatment) Went. Then, the water washing by the spray using well water was performed.
On the lithographic printing plate support after the alkali metal silicate treatment obtained as described above, an undercoat solution having the following composition was applied and dried at 80 ° C. for 15 seconds to form a coating film. The coating amount of the coating film after drying was 10 mg / m ² .

<Undercoat liquid composition>
・ The following polymer compound 0.2g
・ Methanol 100g
・ Water 1g

Furthermore, a heat-sensitive layer coating solution having the following composition was prepared, and the coating amount (heat-sensitive layer coating amount) after drying this heat-sensitive layer coating solution on a lithographic printing plate support that was undercoated was 1.7 g / m ^2. It was applied and dried to form a heat sensitive layer (thermal positive type image recording layer) to obtain a lithographic printing plate precursor.

<Thermosensitive layer coating solution composition>
・ Novolak resin (m-cresol / p-cresol = 60/40, weight average molecular weight 7,000, containing 0.5% by mass of unreacted cresol) 1.0 g
-Cyanine dye A 0.1 g represented by the following structural formula
・ Tetrahydrophthalic anhydride 0.05g
・ 0.002 g of p-toluenesulfonic acid
-Ethyl violet counter ion with 6-hydroxy-β-naphthalenesulfonic acid 0.02 g
-Fluorosurfactant (Megafac F-177, manufactured by Dainippon Ink & Chemicals, Inc.) 0.05g
・ Methyl ethyl ketone 12g

4). Exposure and Development Treatment Each lithographic printing plate precursor obtained above was subjected to image exposure and development treatment by the following method to obtain a lithographic printing plate.
Imagewise exposure of a planographic printing plate precursor using a TrendSetter 3244 manufactured by CREO equipped with a semiconductor laser having an output of 500 mW and a wavelength of 830 nm and a beam diameter of 17 μm (1 / e ² ) at a main scanning speed of 5 m / sec and a plate surface energy amount of 140 mJ / cm ² did. Incidentally, for the evaluation of pepper-like residual film to be described later, were prepared samples was exposed by changing the plate surface energy amount to 20~160mJ / cm ² to 10 mJ / cm ² intervals.
Thereafter, an aqueous solution containing 5.0% by mass of a potassium salt composed of D-sorbite / potassium oxide K ₂ O, which is a combination of a non-reducing sugar and a base, and 0.015% by mass of Orphine AK-02 (manufactured by Nissin Chemical) Development processing was performed using an alkaline developer in which the following compound a was added to 1 L. The development processing was performed using an automatic processor PS900NP (Fuji Photo Film Co., Ltd.) filled with the alkali developer under the conditions of a development temperature of 25 ° C. and 12 seconds. After completion of the development treatment, a lithographic printing plate in which plate making was completed was obtained through a water washing step and treatment with a gum (GU-7 (1: 1)). In addition, even if it was a case where the alkaline developing solution which added the following compound b or c by the same addition amount instead of the compound a was used, it was able to develop similarly.
<Compounds a to c>
Compound a: C ₁₂ H ₂₅ N (CH ₂ CH ₂ COONa) ₂
Compound _{b: C 12 H 25 O (} CH 2 CH 2 O) 7 H
Compound c: (C ₆ H ₁₃ ) ₂ CHO (CH ₂ CH ₂ O) ₂₀ H

5. Evaluation of planographic printing plate The following method was used to evaluate the occurrence of a pot-like residual film, stain resistance, and printing durability of the planographic printing plate obtained above.
(1) Presence or absence of pot-like residual film The non-image part after development of the sample exposed with each plate surface energy amount was observed with an optical microscope at a magnification of 100 times, and the presence or absence of a pot in an area of 1 mm square was examined. The presence or absence of a pot-like residual film was evaluated based on the minimum value of the plate surface energy amount of the sample in which no spots were observed. This means that the smaller the amount of plate surface energy, the harder the formation of a pot-like residual film.
The results are shown in Tables 1 and 2.

(2) Stain resistance With respect to the stain resistance, blanket stains and stains after being left (anti-stain resistance) were evaluated.
Using a Mitsubishi diamond type F2 printing machine (manufactured by Mitsubishi Heavy Industries, Ltd.), printing was performed using DIC-GEOS (s) red ink, and the blanket stain after printing 10,000 sheets was visually evaluated.
The results are shown in Tables 1 and 2. In order from the one with less dirt on the blanket, it is represented by ◎, ○, ○ △.

Moreover, the stain | pollution | contamination after standing was evaluated with the following method.
After evaluating the stain on the blanket, the ink was removed from the surface of the plate, once removed from the printing press, and left in the room for 1 hour. Thereafter, it was evaluated based on the ease of ink removal from the non-image area when the printer was attached to the printer again and printing was started (the number of printed sheets required until ink adhesion on the non-image area was not recognized).
The results are shown in Tables 1 and 2. Those that are easy to pay (one with a small number of printed sheets) have good stains and are represented by ○, ○ △, and Δ in order from the one that is easy to pay.

(3) Printing durability With a Lithlon printing machine manufactured by Komori Corporation, printing was performed using DIC-GEOS (N) black ink manufactured by Dainippon Ink & Chemicals, Inc. Printing durability was evaluated based on the number of printed sheets at the time when it was recognized.
The printing durability was expressed as a relative value when the number of printed lithographic printing plates provided with an image recording layer on the lithographic printing plate support of Comparative Example 1 was 100.

As is apparent from Tables 1 and 2, a lithographic printing plate support obtained by subjecting an aluminum plate to a surface roughening treatment and an anodizing treatment, having a center line average roughness _Ra of 0.55 μm. The grain shape of the surface is a structure in which a large wave structure, a medium wave structure and a small wave structure are superimposed, and the number of recesses having a depth of 3 μm or more existing on the surface is 10 to 60 / mm. the first aspect of the lithographic printing plate support of the present invention which is a ^2, and a center line average roughness R _a is less than 0.60 .mu.m, grain shape of the surface, large wave structure and the medium wave structure and small wave The number of recesses having a depth of 3 μm or more existing on the surface is 10 to 120 / mm ² , and the number of recesses having a depth of 4 μm or more existing on the surface is 20 this onset with a second aspect of the lithographic printing plate support of the present invention which is a number / mm ² or less The lithographic printing plate precursor of (Example 1, Example 2-7) can achieve both good stain resistance and high printing durability. Further, the lithographic printing plate precursor is less likely to generate a pot-like residual film even if the conditions of exposure and development are strict. This means that a pot-like residual film does not occur under normal conditions.
Further, the lithographic printing plate support of the present invention using the aluminum plate II having a Cu content of 0.20 to 0.40% by mass (Examples 5 to 7) has stain resistance and printing durability. Can be compatible at a higher level.

On the other hand, when the surface does not have a grain shape having a structure in which a large wave structure, a medium wave structure, and a small wave structure are superimposed, the stain resistance or the printing durability is poor.
Further, when the number of recesses having a depth of 3 μm or more was too large, the generation of a pot-like residual film was observed. Even when the number of recesses having a depth of 3 μm or more is within the range of the present invention, the occurrence of a pot-like residual film was also observed when the number of recesses having a depth of 4 μm or more was too large. That is, in these cases, there is a possibility that a pot-like residual film is generated when exposure and development are performed under normal conditions.
Furthermore, when the center line average roughness _Ra is 0.55 μm or more (first embodiment) or 0.60 or more (second embodiment), the occurrence of a pot-like residual film was observed.

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 a graph which shows an example of the alternating waveform current waveform figure used for the electrochemical roughening process in preparation 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 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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aluminum plate 2, 4 Roller-shaped brush 3 Polishing slurry liquid 5, 6, 7, 8 Support roller 11 Aluminum plate 12 Radial drum roller 13a, 13b Main electrode 14 Electrolytic process liquid 15 Electrolyte supply port 16 Slit 17 Electrolyte path 18 Auxiliary anode 19a, 19b Thyristor 20 AC power supply 40 Main electrolytic cell 50 Auxiliary anode tank 410 Anodizing device 412 Power supply tank 414 Electrolytic treatment tank 416 Aluminum plate 418, 426 Electrolytic solution 420 Power supply electrode 422, 428 Roller 424 Nip roller 430 Electrolytic electrode 432 Tank wall 434 DC power supply

Claims (4)

A lithographic printing plate support obtained by subjecting an aluminum plate to a surface roughening treatment and an anodizing treatment,
The center line average roughness _Ra is less than 0.60 μm,
The grain shape of the surface is a structure in which a large wave structure with an average wavelength of 5 to 100 μm, a medium wave structure with an average opening diameter of 0.5 to 5 μm, and a small wave structure with an average opening diameter of 0.01 to 0.2 μm are superimposed. ,And,
For lithographic printing plates in which the number of recesses having a depth of 3 μm or more existing on the surface is 10 to 120 / mm ² and the number of recesses having a depth of 4 μm or more existing on the surface is 20 / mm ² or less Support. In the aluminum plate, Fe is 0.20 to 0.50 mass%, Si is 0.03 to 0.15 mass%, Ti is 0.05 mass% or less, and Cu is 0.020 to 0.040 mass%. The support for a lithographic printing plate according to claim 1, wherein the support is an aluminum plate comprising Al and inevitable impurities. The lithographic printing plate support according to claim 1 or 2 , wherein an average of a ratio of a depth to an opening diameter of the small wave structure is 0.2 or more. A lithographic printing plate precursor comprising an image recording layer provided on the lithographic printing plate support according to any one of claims 1 to 3 .

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