【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板として使用す
るアルミニウム素板、特に粗面化処理により均一
な凹凸面を生成して感光膜との密着性を向上し、
版板として印刷中の非画線部の汚れを防止し、画
線部の調子再現性及び色調（明度）が良好で、更
に版板を版胴に巻付ける折曲げ部も十分な耐久力
を有するオフセツト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
ツト印刷用の版板に広く用いられている。従来版
板として使用するAl素板には、純Al系のJIS1050
（純度99.5wt％以上の純Al）、JIS1100（Al−0.05〜
0.20wt％Cu）、Al合金系のJIS3003（Al−1.0〜
1.5wt％Mn−0.05〜0.20wt％Cu）からなる厚さ
0.1〜0.3mmの板が用いられている。これ等Al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、感光剤を
塗布し、露光現像を行つて版板としている。
このような版板は通常印刷機の版胴に巻付けら
れて湿し水の存在のもとに、インキを画線部上に
付着させ、ゴムブランケツトに転写して表面に印
刷を行なつている。このような版板の耐刷力は３
万枚前後であり、前記粗面化は感光剤の付着性と
印刷中の保水性、更に印刷時の調子再現性を向上
させるもので、素板に版板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
塗布し、露光現像して版板とすることも行なわれ
ている。
この陽極酸化処理を施した版板の耐刷力は７万
〜15万枚程度である。
このような印刷用Al素板には次のような特性
が要求されている。
(A) 粗面化処理により均一な凹凸面を生成するこ
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が生じないこと。
(D) 画線部の調子再現性が良いこと。
(E) 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。
(F) 版板を版胴に巻付ける折曲げ部が十分な耐久
力を有すること。
これ等特性中(A)は基本的な特性であつて凹凸が
不均一になると(B)〜(D)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素板の表
面を均一に粗面化するためには、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JIS1050相当のAl素板が用いられている。
The present invention relates to an aluminum base plate used as a printing plate for offset printing, and in particular to a roughened aluminum plate that produces a uniform uneven surface to improve adhesion to a photoresist film.
It prevents staining of the non-image areas during printing as a printing plate, has good tone reproducibility and color tone (brightness) in the printing areas, and has sufficient durability at the folded part where the printing plate is wrapped around the printing cylinder. The present invention relates to an aluminum blank plate for offset printing. Aluminum (Al) is generally lightweight, strong,
Because of its excellent surface treatment properties and corrosion resistance, it is widely used in printing plates for offset printing. The Al base plate used as the conventional printing plate is pure Al based JIS1050.
(Pure Al with a purity of 99.5wt% or more), JIS1100 (Al−0.05~
0.20wt%Cu), Al alloy-based JIS3003 (Al−1.0~
Thickness consisting of 1.5wt%Mn−0.05~0.20wt%Cu)
A plate of 0.1 to 0.3 mm is used. The surface of these Al blank 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, followed by exposure and development. It is used as a board. This type of printing plate is usually wrapped around the printing cylinder of a printing press, and in the presence of dampening water, ink is deposited on the image area and transferred to a rubber blanket to print on the surface. ing. The printing durability of such a printing plate is 3
The roughening process improves the adhesion of photosensitizers, water retention during printing, and tone reproducibility during printing, and is an essential requirement for giving the base plate its function as a printing plate. be. In addition, in order to improve printing durability, anodizing treatment is applied after roughening the surface to a thickness of 1~
It is also practiced to form a printing plate by forming an anodic oxide film of about 3μ, applying a photosensitive agent, and exposing and developing it. The printing plate subjected to this anodizing treatment has a printing durability of approximately 70,000 to 150,000 sheets. The following properties are required for such printing Al base plates. (A) Generating a uniform uneven surface by roughening treatment. (B) Good adhesion of the photoresist film. (C) No stains should occur in non-print areas during printing. (D) Good tone reproducibility in the printed area. (E) 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. (F) The bending part where the plate is wrapped around the plate cylinder must have sufficient durability. Among these characteristics, (A) is a basic characteristic, and if the unevenness becomes uneven, it will affect the characteristics (B) to (D), and good printing durability will not be obtained. In order to uniformly roughen the surface of a blank plate by electrolytic etching, the selection of the blank plate is important, and generally an Al blank plate equivalent to JIS 1050 containing the impurities shown in Table 1 is used.
【表】
しかしながらJIS1050相当のAl素素板を使用し
た場合でも前記(A)，(C)，(D)及び(E)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、しかも地の色調が黒味を帯び
る。また版板として印刷中に非画線部にインキが
付着して印刷物を汚したり、画線部の調子再現性
が悪いという欠点があつた。
本発明はこれに鑑み種々研究の結果、前記(A)〜
(D)の特性を改善し、更に(E)の特性を満足すると同
時に(F)の特性も兼ねそなえたオフセツト印刷用ア
ルミニウム素板を開発したもので、Si含有量が
0.02〜0.15wt％（以下wt％を単に％と記載）、Fe
含有量が0.1〜0.5％、不純物としてのCu含有量が
0.003％以下、残部Alと不可避的不純物からなる
ことを特徴とするものである。
即ち、本発明者等は印刷中の汚れ発生の過程に
つにて種々検討の結果、印刷中の版板は非画線部
において常に湿し水により漏れており、長時間の
使用において、Alと水分が反応して腐食生成物
を発生し、この部分にインキが付着することによ
り、印刷物に汚れが生ずることを知見し、これに
基づいて純Alの腐食に及ぼす不純物の影響につ
いて検討した結果、Al素板中に不純物として含
まれるCuが、版板の場合には極く微量であつて
も、その含有量の増加と共に耐食性を低下し、版
板として印刷中に非画線部の汚れを増大させるこ
とが判つた。
例えばAl純度99.70％以上のAl地金を用い、そ
の中からCu含有量の微量なものから多いものを
選別し、またCuを添加してCu含有量の異なるAl
素板を作成し、これについて各種のテストを行な
つた結果、Cu含有量が0.005％、0.01％、0.05％
と多くなるに従つて版板として印刷中に印刷物の
汚れ発生が増大し、電解エツチングにおいても凹
凸の生成が不均一となる。
本発明はこれらの知見に基づき、更に検討の結
果、Al素板中の不純物であるCu含有量を厳しく
制限することにより、電解エツチングにおける凹
凸の生成を均一化し、かつAl素板の粗面化後の
色調、感光膜の密着性及び版板として印刷中の非
画線部の汚れ性を改善したものである。またAl
素板中に含まれるFe及びSi含有量を特定の範囲
に規制することにより、前記特性を損なうことな
く、版板として版胴へ巻付ける折曲げ部が印刷中
に折切れを生ずるのを防止する十分な強度を付与
したものである。
しかして本発明においてAl素板の組成を上記
の如く限定したのは次の理由によるものである。
不純物であるCu含有量を0.003％以下と限定し
したのは、0.003％を越えてCuを含有すると、電
解エツチングにより生成した凹凸が不均一とな
り、粗面化後の色調も低下し、版板として印刷中
の非画線部における汚れ性が低下するためであ
る。また素板中に含まれるSi含有量を0.02〜0.15
％、Fe含有量を0.1〜0.5％と限定したのは、何れ
かが下限未満では版板として印刷中に版胴へ巻付
けた折曲げ部より折切れを生じ、何れかが上限を
越えると、電解エツチングにより均一な凹凸が得
られないためである。
尚、本発明Al素板の製造において、最終素板
のCu含有量を0.003％以下、Fe含有量を0.1〜0.5
％Si含有量を0.02〜0.15％とする必要があるため、
Al純度99.70以上のAl地金より適合するものを選
んで使用するか又は、Fe、Siについては要に応
じて上記範囲に添加して使用することが望まし
い。またCu、Si、Fe以外の不純物としては、
JIS1050相当のAl地金に含まれる不純物（Mn0.05
％以下、Mg0.05％以下、Zn0.05％以下、Ti0.03
％以下）程度であれば、本発明Al素板の特性を
何等損なう恐れはない。
以下、本発明Al素板を実施例について詳細に
説明する。
実施例 (1)
各種グレードのAl地金（Al純度99.50％以上、
99.70％以上、99.90％以上）を用い、必要に応じ
てCu、Si、Feを添加して通常の方法により溶解
鋳造、Cu、Si、Feについて第２表に示す組成の
鋳魂を得た。この鋳魂の両面を面削して厚さ350
mm、巾1000mm、長さ2000mmとし、通常の方法で均
質処理した後熱間圧延し、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Al素板に仕上
げた。この素板を下記の条件で処理し、電解エツ
チングによる凹凸の均一性と、電解エツチング後
の明度を測定した。
また、露光現像を行なつた版板を印刷機に巻付
けて３万枚の印刷を行ない、印刷物の汚れと版板
の折切れを調べた。
これ等の結果を第２表に併記した。
尚、電解エツチングの明度（Ｌ値）はハンター
式測色計で測定した。
処理条件
市販の洗剤で脱脂した後、液温50℃の水酸化ナ
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％硝酸液中で５分間
スマツジ除却を行なつた後、水洗乾燥した。これ
に感光剤を塗布し、露光現像して版板とした。[Table] However, even when using an Al blank plate equivalent to JIS1050, there are problems with the characteristics (A), (C), (D), and (E) above. That is, due to electrolytic etching, non-uniform and deep unevenness is formed, and the background color tone becomes blackish. Further, during printing as a printing plate, ink adheres to non-image areas, staining the printed matter, and the tone reproducibility of image areas is poor. In view of this, the present invention has been developed as a result of various studies, and as a result,
We have developed an aluminum base plate for offset printing that improves the characteristics of (D), satisfies the characteristics of (E), and also has the characteristics of (F).
0.02-0.15wt% (hereinafter wt% is simply written as %), Fe
The content is 0.1~0.5%, Cu content as impurity
It is characterized by being composed of 0.003% or less, the balance being Al and unavoidable impurities. In other words, as a result of various studies on the process of stain generation during printing, the present inventors found that dampening water constantly leaks from non-printing areas of printing plates during printing, and that Al We discovered that the reaction between aluminum and moisture generates corrosion products, and ink adheres to these areas, causing stains on printed matter.Based on this, we investigated the effect of impurities on the corrosion of pure aluminum. Even if the amount of Cu contained as an impurity in the Al base plate is extremely small in the case of printing plates, corrosion resistance decreases as the content increases, and stains in non-image areas during printing as printing plates. It was found that it increases For example, using Al ingots with an Al purity of 99.70% or higher, selecting those with a trace amount of Cu content to those with a high amount of Cu, and adding Cu to produce Al ingots with different Cu contents.
After creating a blank plate and conducting various tests on it, the Cu content was found to be 0.005%, 0.01%, and 0.05%.
As the number increases, the occurrence of stains on the printed matter increases during printing as a printing plate, and unevenness becomes uneven even during electrolytic etching. The present invention is based on these findings, and as a result of further studies, it is possible to uniformize the formation of unevenness in electrolytic etching and to improve the surface roughness of the Al blank by strictly limiting the content of Cu, which is an impurity, in the Al blank. This improves the subsequent color tone, the adhesion of the photosensitive film, and the stain resistance of non-image areas during printing as a printing plate. Also Al
By regulating the Fe and Si contents contained in the base plate within a specific range, the folded part that is wrapped around the plate cylinder as a plate can be prevented from breaking during printing without impairing the above characteristics. It has been given sufficient strength to However, in the present invention, the composition of the Al blank plate is limited as described above for the following reasons. The reason why we limited the content of Cu, which is an impurity, to 0.003% or less is because if Cu content exceeds 0.003%, the unevenness generated by electrolytic etching will become uneven, and the color tone after roughening will also deteriorate. This is because the stain resistance in non-image areas during printing is reduced. In addition, the Si content contained in the base plate is 0.02 to 0.15.
% and Fe content are limited to 0.1 to 0.5%.If either of them is below the lower limit, the plate will break at the bent part wrapped around the plate cylinder during printing, and if any of them exceeds the upper limit, This is because uniform unevenness cannot be obtained by electrolytic etching. In the production of the Al blank plate of the present invention, the Cu content of the final blank plate is 0.003% or less, and the Fe content is 0.1 to 0.5%.
Since the %Si content needs to be 0.02-0.15%,
It is desirable to select and use a suitable Al base metal with an Al purity of 99.70 or higher, or to use Fe and Si by adding them within the above range as necessary. In addition, impurities other than Cu, Si, and Fe include:
Impurities contained in Al base metal equivalent to JIS1050 (Mn0.05
% or less, Mg 0.05% or less, Zn 0.05% or less, Ti 0.03
% or less), there is no fear that the properties of the Al blank plate of the present invention will be impaired in any way. Examples of the Al blank plate of the present invention will be described in detail below. Examples (1) Various grades of Al ingots (Al purity of 99.50% or more,
99.70% or more, 99.90% or more), and by adding Cu, Si, and Fe as necessary, melting and casting was performed in a usual manner to obtain a cast soul having the composition shown in Table 2 for Cu, Si, and Fe. Both sides of this cast soul are faceted to a thickness of 350 mm.
mm, width 1000 mm, and length 2000 mm. After homogenization using the usual method, hot rolling was carried out, followed by repeated cold rolling and intermediate annealing to produce a 0.2 mm thick aluminum base plate for printing. This blank plate was processed under the following conditions, and the uniformity of unevenness due to electrolytic etching and the brightness after electrolytic etching were measured. In addition, the exposed and developed plate was wrapped around a printing press and 30,000 copies were printed, and stains on the printed matter and breakage of the plate were examined. These results are also listed in Table 2. The brightness (L value) of electrolytic etching was measured using a Hunter colorimeter. Processing conditions: After degreasing with a commercially available detergent, etching was performed for 1 minute using a 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. After removing smudges from this in a 25% nitric acid solution at a temperature of 50° C. for 5 minutes, it was washed with water and dried. This was coated with a photosensitive agent, exposed and developed to form a printing plate.
【表】【table】
【表】
第２表から明らかなように、本発明素板No.１〜
No.６は電解エツチング後の明度Ｌが高く、電解エ
ツチングによる凹凸も均一で、版板として印刷中
の印刷物の汚れは発生せず、版板へ巻付けた折曲
げ部の折切れも発生しないことが判る。
これに対し、Si及びFe含有量が如何なる量で
あつてもCu含有量が0.003％を越える比較素板No.
７、No.９、No.11、No.13、No.15、No.17従来素板No.19
では何れも版板として印刷中の印刷物に汚れが認
められ、明度Ｌも低いことが判る。またCu含有
量が0.003％以下であつてもSi又はFeの含有量が
本発明で規制する範囲より低い比較素板No.８、No.
９、No.10、No.11、No.18では何れも版胴へ巻付ける
折曲げ部に折切れが生じ、Si又はFe含有量が本
発明で規制する範囲より高い比較素板No.12、No.
13、No.14、No.15、No.16、No.17、従来素板19では何
れも電解エツチングによる凹凸が不均一となるこ
とが判る。
実施例 (2)
第２表に示す組成の鋳魂を実施例(1)と同様にし
て厚さ0.2mmの印刷用素板とし、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％硫酸浴中で電流密度
1A／dm2により３分間直流電解し、表面に厚さ
約1μの陽極酸化皮膜を形成した。これに感光剤
を塗布し、露光現像して版板とし、印刷機に巻付
けて印刷を行なつた。
その結果、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
れず、明度も高く、版胴へ巻付けた折曲げ部の折
切れもなく、電解エツチングによる凹凸も均一で
あつた。
これに対し比較素板及び従来素板を用いたもの
はSi及びFeの含有量がいかなる量でもCu含有量
が0.003％を越えるものは印刷物に汚れが発生し、
またSi及びFe含有量が本発明で規制した範囲よ
り低いものでは版胴へ巻付けた折曲げ部に折切れ
を生じ、本発明で規制した範囲より高いものでは
電解エツチングによる凹凸が不均一であつた。
このように本発明によれば印刷物Al素板とし
て、Alの含まれる不純物としてのCu、Fe及ぼSi
の含有量を所定の範囲に規制することにより、粗
面化処理による凹凸を均一化して感光膜との密着
性を改善し、版板として印刷中の非画線部の汚れ
を防止すると共に、画線部の調子、再現性及び色
調を改善し、版板の折曲げ部も十分な耐久力を有
する顕著な効果を奏するものである。[Table] As is clear from Table 2, the present invention blank No. 1~
No. 6 has a high brightness L after electrolytic etching, and the unevenness caused by electrolytic etching is uniform, so there is no staining of printed matter during printing as a printing plate, and there is no breakage of the folded part wrapped around the printing plate. I understand that. On the other hand, comparative blank No. 1 has a Cu content exceeding 0.003% no matter what the Si and Fe contents are.
7, No.9, No.11, No.13, No.15, No.17 Conventional blank board No.19
It can be seen that in both cases, the printed matter being printed as a printing plate has stains and the lightness L is low. Furthermore, even if the Cu content is 0.003% or less, the Si or Fe content is lower than the range regulated by the present invention in Comparative Materials No. 8 and No.
9, No. 10, No. 11, and No. 18 all had breakage at the bent part wrapped around the plate cylinder, and comparative blank No. 12 had a Si or Fe content higher than the range regulated by the present invention. , No.
13, No. 14, No. 15, No. 16, No. 17, and the conventional blank plate 19, it can be seen that the unevenness due to electrolytic etching is non-uniform. Example (2) The casting soul having the composition shown in Table 2 was made into a base plate for printing with a thickness of 0.2 mm in the same manner as in Example (1), and this was used as Example (1).
After electrolytic etching and smudge removal in the same manner as above, the current density was
Direct current electrolysis was carried out at 1 A/dm 2 for 3 minutes to form an anodic oxide film with a thickness of about 1 μm on the surface. This was coated with a photosensitive agent, exposed and developed to form a printing plate, and then wrapped around a printing press for printing. As a result, even after printing 200,000 sheets using the base plate of the present invention, the printed matter showed no stains at all, had high brightness, and did not break at the bent portion wrapped around the plate cylinder. The unevenness caused by electrolytic etching was also uniform. On the other hand, for comparison blanks and those using conventional blanks, if the Cu content exceeds 0.003% no matter the amount of Si and Fe, the printed matter will be stained.
In addition, if the Si and Fe content is lower than the range regulated by the present invention, breakage will occur at the bent part wrapped around the plate cylinder, and if the Si and Fe content is higher than the range regulated by the present invention, unevenness due to electrolytic etching may be uneven. It was hot. As described above, according to the present invention, Cu, Fe, and Si as impurities contained in Al can be used as printed Al base plates.
By regulating the content within a predetermined range, unevenness caused by surface roughening treatment is made uniform, improving adhesion with the photosensitive film, and preventing staining of non-image areas during printing as a printing plate. This has the remarkable effect of improving the tone, reproducibility, and color tone of the printed area, and providing sufficient durability to the folded portion of the printing plate.