【発明の詳細な説明】[Detailed description of the invention]
本発明はオフセツト印刷用の版材として使用す
る印刷用アルミニウム素板、特に粗面化後の色調
が優れ現像後画像がみやすく、且つ印刷中に非画
線部に汚れを生じない印刷用アルミニウム素板に
関するものである。
一般にアルミニウム（Al）は軽量で強度、表
面処理性及び耐食性が優れているため、オフセツ
ト印刷用の版材に広く用いられている。従来、版
材として使用する印刷用アルミニウム素板には純
Al系として、JIS1050（Al純度99.5重量％以上、
以下％は重量％を示す。）JIS1100（Al−0.05〜
0.20％Cu合金、Al純度99.0％以上）Al合金系と
してJIS3003（Al−1.0〜1.5％Mn−0.05〜0.20％Cu
合金）からなる厚さ0.1〜0.3mmの素板が用いられ
ている。これ等、素板は通常ボールグレーニン
グ、ブラシグレーニングなどの機械的な方法、又
は電解エツチングなどの化学的な方法により表面
を粗面化した後、感光剤が塗布され、印刷用の版
材となる。このようにして得られた版材は、露
光、現像等の製版処理を行なつたのち、印刷機の
版胴に巻きつけ湿し水の存在のもとに、インキを
画線部上に付着させて、ゴムブランケツトに転写
後紙面に印刷する。このように処理された印刷版
の耐刷力は３万枚前後である。前記粗面化は感光
剤の付着性と印刷中の保水性を向上させるもの
で、素板に印刷用版としての機能を与える不可欠
の要件である。また、耐刷力を向上させるため、
粗面化の後に陽極酸化処理を施して厚さ１〜3μ
程度の陽極酸化皮膜を形成してから感光剤を塗布
することもよく行なわれている。この陽極酸化処
理した場合の耐刷力は15万枚前後である。このよ
うな印刷用素板には次のような特性が要求されて
いる。
(A) 粗面化処理で均一な凹凸ができること。
(B) 感光膜の密着性が良いこと。
(C) 印刷中に非画線部に汚れを生じないこと。
(D) 現像後の画線部検査の際、画線部が見易いた
めに地の色調（粗面化後の色調）が白くなるこ
と。
これ等の特性中、(A)は基本的な特性であつて、凹
凸が不均一になると(B)〜(C)の特性に影響し、良い
耐刷力が得られない。電解エツチングにより印刷
用素板の表面を粗面化する場合には素板の選択が
重要であり、一般には、第１表に示す不純物を含
有する1050相当のAl素板が用いられている。し
かしながら1050相当のAl素板を使用した場合で
も前記(A)、(C)及び(D)の特性に難点がある。即ち、
電解エツチングにより、不均一で深い凹凸が形成
される結果、地の色調が黒味を帯びていること。
また印刷中に非画線部にインキが付着して印刷物
が汚れるという欠点があつた。
The present invention is an aluminum base plate for printing used as a plate material for offset printing, especially an aluminum base plate for printing that has excellent color tone after roughening and is easy to see an image after development, and does not cause stains in non-image areas during printing. It's about the board. In general, aluminum (Al) is widely used as a plate material for offset printing because it is lightweight and has excellent strength, surface treatment properties, and corrosion resistance. Conventionally, printing aluminum base plates used as plate materials contain pure
As Al-based, JIS1050 (Al purity 99.5% by weight or more,
Below, % indicates weight %. ) JIS1100 (Al−0.05~
0.20%Cu alloy, Al purity 99.0% or more) JIS3003 (Al-1.0~1.5%Mn-0.05~0.20%Cu)
A blank plate of 0.1 to 0.3 mm thick is used. The surface of these raw plates is usually roughened by mechanical methods such as ball graining or brush graining, or chemical methods such as electrolytic etching, and then a photosensitive agent is applied and used as a printing plate. becomes. After the plate material obtained in this way is subjected to plate-making processes such as exposure and development, it is wrapped around the plate cylinder of a printing press and ink is applied onto the image area in the presence of dampening water. Then, after transferring it to the rubber blanket, print it on the paper surface. The printing plate treated in this way has a printing durability of around 30,000 sheets. The surface roughening improves the adhesion of the photosensitive agent and the water retention during printing, and is an essential requirement for providing the base plate with the function of a printing plate. In addition, to improve printing durability,
After roughening, anodic oxidation treatment is applied to a thickness of 1 to 3 μm.
It is also common practice to apply a photosensitizer after forming a certain amount of anodized film. The printing durability after this anodizing treatment is approximately 150,000 sheets. Such printing blanks are required to have the following characteristics. (A) Uniform unevenness can be created through surface roughening treatment. (B) Good adhesion of the photoresist film. (C) No smearing should occur in non-print areas during printing. (D) When inspecting the image area after development, the color tone of the background (color tone after surface roughening) becomes white because the image area is easy to see. Among these characteristics, (A) is a basic characteristic, and if the unevenness becomes uneven, it will affect the characteristics (B) to (C), and good printing durability will not be obtained. When roughening the surface of a printing base plate by electrolytic etching, the selection of the base plate is important, and generally an Al base plate equivalent to 1050 containing the impurities shown in Table 1 is used. However, even when an Al blank plate equivalent to 1050 is used, there are problems with the characteristics (A), (C), and (D) above. That is,
As a result of electrolytic etching, uneven and deep unevenness is formed, resulting in a blackish tone to the background.
Another drawback was that ink adhered to non-image areas during printing, staining the printed matter.
【表】
本発明はこれに鑑み、印刷中に汚れが発生する
過程について、種々検討の結果、印刷中の版材は
非画線部において常に湿し水で濡れており長時間
の使用において、Alと水分が反応し、腐食生成
物が発生し、この部分にインキが付着するように
なつて印刷物に汚れを生ずることを知見し、更に
検討の結果、Al素板中の不純物であるCu元素を
厳しく制限することにより粗面化後の色調に優れ
（従つて現像後の画像がみやすく）印刷中に非画
線部に汚れを生じない印刷用アルミニウム素板を
開発したもので、不純物として含まれるCuが
0.003％以下であり、且つAl純度99.5％以上のAl
からなることを特徴とする印刷用アルミニウム素
板である。
即ち本発明は印刷中の汚れ発生が印刷版材の腐
食により起ることを知り、純Alの腐食に対する
不純物の影響について検討した結果、Al素板中
に不純分として含まれるCuが版材の場合、極く
微量であつても、その量によつてAlの耐食性が
変化し、その結果、汚れ性が異なつてくることが
認められた。即ちAl純度99.70％以上のAl地金を
用い、これよりCuの微量のものから多いものに
ついて選別し、又はCuを添加してCu量の異るAl
素板を作成し、各種テストを行なつた結果、Cu
量が0.005％、0.01％、0.05％と多くなるに従つて
汚れの発生する度合が多くなつた。更にCu量の
影響についてテストを行なつたところ実質的に含
有するCu量が0.003％以下であれば粗面化後の色
調が優れ、印刷中に非画線部に汚れが発生しない
ことが判つた。従来使用されている1050相当の
Al素板でも第１表に示す如く、不純物としてCu
を0.005〜0.05％含んでおり、これが汚れ発生の
原因となつているものである。
また、従来の1050相当のAl素板に含まれる其
の他の不純物の影響について調べたところ、Al
純度99.5％以上のAl素板に含まれる程度の不純物
であれば、Cuを除けば問題ないことが判つた。
即ちCu0.003％以下、Si0.25％以下、Fe0.40％以
下、Mn0.05％以下、Mg0.05％以下、Zn0.05％以
下、Ti0.03％以下、その他の元素がそれぞれ0.03
％以下で、Al純度99.5％以上のAlなら問題ない。
このようなAlからなる印刷用アルミニウム素材
は、電解エツチングによる粗面化において深い凹
凸が発生することなく、均一な粗面が得られるた
め、前記(A)、(B)、(D)の特性を向上し得るとともに
(C)の特性も向上し得るものである。
尚、本発明による印刷用アルミニウム素板を製
造するに当つては、最終素板のCu量0.003％以下、
Al純度99.5％以上とするため、Al純度99.70％以
上のAl地金よりCu量の適合するものを選んで使
用するのが望ましい。
次に本発明を実施例について説明する。
実施例 １
各種のグレードのAl地金（Al純度99.50％以
上、99.70％以上、99.85％以上、99.90％以上）を
用い、Cu、Si、Fe等の成分を必要に応じて添加
し、普通の方法で溶解鋳造して、第２表に示す組
成の鋳塊を得た。この鋳塊の両面を面削し、350
mm×1000mm×2000mmの鋳塊としたのち、普通の方
法で均質処理、熱間圧延し、続いて冷間圧延と中
間焼鈍を繰返して厚さ0.2mmの印刷用素板に仕上
げた。この板を下記の条件で処理して印刷版材に
仕上げ、これを印刷機にとりつけて３万枚の印刷
を行ない、印刷物の汚れを調べた。その結果を第
３表に示す。尚、電解エツチング後の明度（Ｌ
値）をハンター式測色計で測定した。その結果を
併記した。
処理条件
市販の洗剤にて脱脂後、液温50℃の５％水酸化
ナトリウム溶液を用いて１分間エツチングを行な
い、続いて液温20℃の1.5％硝酸液中で電流密度
30A／ｄm2により１分間交流電解エツチングを行
なつた。これを液温50℃の25％硫酸液中で５分間
スマツジ除去を行なつた後、水洗乾燥した。この
ようにして作成したエツチング材に感光剤を塗布
し、露光現像を行なつて版材を作成した。[Table] In view of this, the present invention has conducted various studies on the process by which stains occur during printing, and has found that the plate material during printing is always wet with dampening water in the non-printing area, and when used for a long time, It was discovered that aluminum reacts with moisture, producing corrosion products, and ink adheres to this area, causing stains on printed matter.As a result of further investigation, it was discovered that Cu element, which is an impurity in the Al base plate, We have developed an aluminum base plate for printing that has excellent color tone after roughening by strictly restricting the surface roughness (therefore, the image after development is easy to see) and does not cause stains in non-image areas during printing. Cu is
Al with an Al purity of 0.003% or less and an Al purity of 99.5% or more
This is an aluminum base plate for printing, characterized by consisting of: That is, the present invention found that staining during printing is caused by corrosion of the printing plate material, and as a result of studying the influence of impurities on the corrosion of pure Al, it was found that Cu, which is contained as an impurity in the Al base plate, is present in the plate material. In this case, it was found that even if the amount was extremely small, the corrosion resistance of Al changed depending on the amount, and as a result, the staining resistance varied. That is, using Al ingots with an Al purity of 99.70% or more, sorting them from those with a trace amount of Cu to those with a large amount of Cu, or adding Cu to produce Al with different amounts of Cu.
As a result of creating a raw plate and conducting various tests, Cu
As the amount increased from 0.005% to 0.01% to 0.05%, the degree of staining increased. Furthermore, we conducted a test on the effect of the amount of Cu and found that if the actual amount of Cu contained is 0.003% or less, the color tone after roughening is excellent and no stains occur in non-image areas during printing. Ivy. Equivalent to the conventionally used 1050
Even in the Al base plate, as shown in Table 1, Cu is present as an impurity.
This is the cause of stains. In addition, when we investigated the effects of other impurities contained in conventional Al blank plates equivalent to 1050, we found that Al
It was found that there would be no problem with impurities as long as they were contained in Al base plates with a purity of 99.5% or higher, with the exception of Cu.
That is, Cu 0.003% or less, Si 0.25% or less, Fe 0.40% or less, Mn 0.05% or less, Mg 0.05% or less, Zn 0.05% or less, Ti 0.03% or less, and other elements each 0.03% or less.
% or less, and there is no problem if the Al purity is 99.5% or more.
This kind of aluminum material for printing made of Al can be roughened by electrolytic etching without producing deep unevenness, and a uniformly roughened surface can be obtained, so it has the characteristics (A), (B), and (D) above. as well as improve
The properties of (C) can also be improved. In addition, when manufacturing the printing aluminum base plate according to the present invention, the Cu content of the final base plate is 0.003% or less,
In order to achieve an Al purity of 99.5% or higher, it is preferable to select and use an Al base metal with an Al purity of 99.70% or higher that has a suitable amount of Cu. Next, the present invention will be explained with reference to examples. Example 1 Al ingots of various grades (Al purity of 99.50% or more, 99.70% or more, 99.85% or more, 99.90% or more) were used, and components such as Cu, Si, and Fe were added as necessary, and ordinary The ingots having the compositions shown in Table 2 were obtained by melting and casting according to the method. Both sides of this ingot were face-milled and
After forming an ingot with dimensions of mm x 1000 mm x 2000 mm, it was homogenized and hot rolled using the usual method, followed by repeated cold rolling and intermediate annealing to produce a printing plate with a thickness of 0.2 mm. This plate was processed under the following conditions to produce a printing plate material, which was attached to a printing machine and printed 30,000 sheets, and the printed matter was examined for stains. The results are shown in Table 3. In addition, the brightness after electrolytic etching (L
value) was measured using a Hunter colorimeter. The results are also listed. Processing conditions: After degreasing with a commercially available detergent, etching is performed for 1 minute using a 5% sodium hydroxide solution at a temperature of 50°C, followed by etching at current density in a 1.5% nitric acid solution at a temperature of 20°C.
AC electrolytic etching was performed at 30 A/dm 2 for 1 minute. This was smeared in a 25% sulfuric acid solution at a temperature of 50° C. for 5 minutes, and then washed with water and dried. A photosensitive agent was applied to the etching material thus prepared, and exposure and development were performed to prepare a plate material.
【表】【table】
【表】
第２表及び第３表から判るようにAl純度99.5％
以上のAlでCu不純物が0.003％以下である本発明
アルミニウム素板を用いたものは、電解エツチン
グ後の明度が高く、印刷物の汚れは全く認められ
なかつた。これに対し、Cu不純物が0.003％を越
えるAl及びCu不純物が0.003％未満でもAl純度が
99.5％未満のものは何れも電解エツチング後の明
度が劣り、印刷物には汚れが発生している。
実施例 ２
第２表に示す組成の鋳塊を用い、実施例(1)と同
様にして厚さ0.2mmの印刷用素板に仕上げ、これ
を実施例(1)と同様にして電解エツチング、スマツ
ジ除去を行なつた後、液温20℃の15％硫酸液中で
電流密度1A／ｄm2により３分間直流電解を行な
い、表面に厚さ約1μの陽極酸化皮膜を形成し、
これに感光剤を塗布して露光、現像を行なつて版
材を作成した。これ等の版材を印刷機にとりつ
け、それぞれ印刷を行なつたところ、本発明素板
を用いたものは、20万枚の印刷を行なつても印刷
物には汚れが全く認められなかつた。
これに対し比較素板を用いたものは、何れも15
万枚程度で印刷物に点状の汚れが発生した。
このように本発明素板は粗面化後の色調が優
れ、現像後の画線部検査が容易で、印刷中に非画
線部に汚れを生じない等、顕著な効果を奏するも
のである。[Table] As seen from Tables 2 and 3, Al purity is 99.5%
When using the aluminum base plate of the present invention containing the above Al and Cu impurities of 0.003% or less, the brightness after electrolytic etching was high, and no stains were observed on the printed matter. On the other hand, even if the Cu impurity exceeds 0.003% and the Cu impurity is less than 0.003%, the Al purity
If the value is less than 99.5%, the brightness after electrolytic etching is poor and the printed matter is stained. Example 2 Using an ingot having the composition shown in Table 2, a printing plate with a thickness of 0.2 mm was finished in the same manner as in Example (1), and this was electrolytically etched and etched in the same manner as in Example (1). After removing smudges, DC electrolysis was performed for 3 minutes at a current density of 1A/ dm2 in a 15% sulfuric acid solution at a temperature of 20°C to form an anodic oxide film with a thickness of about 1μ on the surface.
A photosensitive agent was applied to this material, and exposure and development were performed to prepare a plate material. When these plate materials were attached to a printing machine and printed on each, no stains were observed on the printed matter using the base plate of the present invention even after printing 200,000 sheets. On the other hand, those using comparison blanks were all 15
Dot-like stains appeared on the printed matter after about 10,000 copies. As described above, the base plate of the present invention has remarkable effects such as excellent color tone after roughening, easy inspection of image areas after development, and no staining in non-image areas during printing. .