JP4048872B2 - Plate inspection method for printing plate materials - Google Patents

Description

【０１１５】
本発明では糖類を含有する層を水溶液で塗布形成することが好ましいため、水溶液から形成された場合は、層中に存在するオリゴ糖が水和物を形成するオリゴ糖である場合は、その融点は水和物の融点であると考えられる。このように、比較的低融点を有しているため、熱溶融性微粒子が溶融する温度範囲や熱融着性微粒子が融着する温度範囲でオリゴ糖も溶融し、熱溶融性微粒子の多孔質親水性層への溶融浸透や熱融着性微粒子の融着といった画像形成を妨げることがない。
【０１１６】
オリゴ糖の中でもトレハロースは、比較的純度の高い状態のものが工業的に安価に入手可能であり、水への溶解度が高いにもかかわらず、吸湿性は非常に低く、機上現像性及び保存性共に非常に良好である。
【０１１７】
又、オリゴ糖水和物を熱溶融させて水和物を除去した後に凝固させると（凝固後短時間のうちは）無水物の結晶となるが、トレハロースは水和物よりも無水物の融点が１００℃以上も高いことが特徴的である。これは赤外線露光で熱溶融し、再凝固した直後の露光済部は高融点で溶融しにくい状態となることを意味し、バンディング等の露光時の画像欠陥を起こしにくくする効果がある。層中のオリゴ糖の含有量としては、層全体の１〜９０質量％が好ましく、１０〜８０質量％がさらに好ましい。
【０１１８】
［赤外線による印刷版材料の画像形成］
本発明に好ましく用いることができる印刷版材料の画像形成は熱により行うことができるが、特に赤外線レーザーによる露光によって行うことが好ましい。
【０１１９】
本発明に係る露光に関し、より具体的には、赤外および／または近赤外領域で発光する、すなわち７００〜１５００ｎｍの波長範囲で発光するレーザーを使用した走査露光が好ましい。レーザーとしてはガスレーザーを用いてもよいが、近赤外領域で発光する半導体レーザーを使用することが特に好ましい。
【０１２０】
本発明の走査露光に好適な装置としては、該半導体レーザーを用いてコンピュータからの画像信号に応じて印刷版材料表面に画像を形成可能な装置であればどのような方式の装置であってもよい。
【０１２１】
一般的には、
（１）平板状保持機構に保持された印刷版材料に一本もしくは複数本のレーザービームを用いて２次元的な走査を行って印刷版材料全面を露光する方式、
（２）固定された円筒状の保持機構の内側に、円筒面に沿って保持された印刷版材料に、円筒内部から一本もしくは複数本のレーザービームを用いて円筒の周方向（主走査方向）に走査しつつ、周方向に直角な方向（副走査方向）に移動させて印刷版材料全面を露光する方式、
（３）回転体としての軸を中心に回転する円筒状ドラム表面に保持された印刷版材料に、円筒外部から一本もしくは複数本のレーザービームを用いてドラムの回転によって周方向（主走査方向）に走査しつつ、周方向に直角な方向（副走査方向）に移動させて印刷版材料全面を露光する方式があげられる。
【０１２２】
本発明に関しては特に（３）の走査露光方式が好ましく、特に印刷装置上で露光を行う装置においては、（３）の露光方式が用いられる。
【０１２３】
【実施例】
実施例１
（基材１〜３）
ａ．基材１
厚さ１７５μｍの透明ＰＥＴフィルムの両面に下記の手順で下塗り層を形成し、基材１とした。基材１の透過濃度をマクベス濃度計：ＴＤ９０４を用いて黒白濃度（Ｖｉｓｕａｌ）で測定したところ、０．０４であった。
【０１２４】
１）第一下塗り層
ＰＥＴ基材の塗布面にコロナ放電処理を施した後、下記組成の塗布液を、２０℃、相対湿度５５％の雰囲気下でワイヤーバーにより乾燥後の膜厚が０．４μｍとなるように塗布した。その後、１４０℃で２分間乾燥を行った。
【０１２５】
〈第１下塗層塗布液〉

以上に蒸留水を加えて１０００ｍｌとし、塗布液とした。
【０１２６】
２）第二下塗り層
上記フィルムの第一下塗り層を形成した面にコロナ放電処理を施した後、下記組成の塗布液を、３５℃、相対湿度２２％の雰囲気下でエアーナイフ方式により乾燥後の膜厚が０．１μｍとなるように塗布した。その後、１４０℃で２分間乾燥を行った。
【０１２７】
〈第２下塗層塗布液〉
ゼラチン ９．６ｇ
界面活性剤（Ａ） ０．４ｇ
硬膜剤（ｂ） ０．１ｇ
【０１２８】
【化１】

【０１２９】
ｂ．基材２
厚さ１７５μｍの医用感材用のブルーに透過着色されたＰＥＴフィルムを用いた以外は基材１と同様にして基材２を得た。基材２の透過濃度は０．１７であった。
【０１３０】
ｃ．基材３
厚さ１７５μｍの白色ＰＥＴフィルムを用いた以外は基材１と同様にして基材３を得た。基材３の透過濃度は０．４２であった。
【０１３１】
（塗布液の作製）
ａ．親水性層塗布液の作製
表２の組成の素材をホモジナイザを用いて十分に攪拌混合した後、濾過して親水性層の塗布液を作製（表中単位記載のない数値は質量部を示す）した。
【０１３２】
【表２】

【０１３３】
ｂ．画像形成層塗布液の作製
表３の組成を十分に混合攪拌した後、濾過して画像形成層用塗布液を作製（表中単位記載のない数値は質量部を示す）した。
【０１３４】
【表３】

【０１３５】
（印刷版材料の作製）
表４に示した基材を用い、親水性層および画像形成層をワイヤーバーで表４に示した乾燥付量となるように塗布して印刷版材料１〜５を作製した。親水性層の塗布乾燥条件は８０℃３分間とし、親水性層を形成した段階で６０℃２４時間のエイジングを行った。次いで、画像形成層を塗布した。画像形成層塗布後の乾燥条件は５５℃３分間とした。各印刷版材料の透過濃度を測定し、表４に示した。
【０１３６】
【表４】

【０１３７】
（画像形成）
画像形成は赤外線レーザー露光により行った。露光には波長８３０ｎｍ、スポット径約１８μｍのレーザービームを用い、レーザービームの焦点を印刷版材料１〜５の表面に合わせて、露光エネルギーを３００ｍｊ／ｃｍ²とした条件で、２４００ｄｐｉ（ｄｐｉとは１インチ、即ち２．５４ｃｍ当たりのドット数を表す）、１７５線で画像を形成した。評価用の画像として、ベタ画像と１〜９９％の網点画像および縦、横、斜め線によるライン＆スペース画像を用いた。
【０１３８】
（印刷方法、印刷評価）
印刷機として三菱重工業（株）製ＤＡＩＹＡ１Ｆ−１を用い、その版胴に露光済の印刷版材料１〜５を取り付け、コート紙、湿し水：アストロマーク３（日研化学研究所製）２質量％、インク（東洋インク（株）製トーヨーキングハイエコーＭ紅）を使用して印刷を行った。印刷開始のシークエンスはＰＳ版の印刷シークエンスで行い、特別な機上現像操作は行わなかった。
【０１３９】
刷り出し時、良好なＳ／Ｎ（非画像部に地汚れがなく、すなわち、画像形成層の非画像部が印刷機上で除去され、かつ、画像部の濃度が適正範囲となっている）を有した印刷物が得られるまでの印刷枚数を評価したところ、印刷版材料１〜５すべてが２０枚以内の良好な刷り出し性を示した。
【０１４０】
（検版時の可視画性評価）
露光済の印刷版材料１〜５を画像形成層側を上にして表５に示すような部材の上に乗せ、上から白色光で照らしながら目視およびルーペで下記の評価基準により可視画性を評価し、結果を表５に示す。
【０１４１】
目視観察での可視画性
◎：非常に良好
○：良好
△：やや不良
×：不良
ルーペ観察での可視画性
◎：ライン＆スペース画像まで明瞭に見える
○：２〜９８％の網点が確認できる
△：不明瞭ではあるが網点が確認できる
×：網点が確認しにくい。
【０１４２】
【表５】

【０１４３】
表５から、本発明の透過濃度を有する、印刷機の版胴に取付けられてから印刷版材料の表面に形成された層の少なくとも一部を除去することにより画像を形成するタイプの印刷版材料に対して、本発明の検版方法が非常に有効であることがわかる。
【０１４４】
【発明の効果】
本発明により、特定の透過濃度を有する印刷版材料を露光して画像形成を行った後のより明瞭でかつ安定した検版を可能とする検版方法を提供することができた。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plate inspection method for a printing plate material, and more particularly to a plate inspection method for a printing plate material capable of forming an image by a computer-to-plate (CTP) method.
[0002]
[Prior art]
With the digitization of print data, there is a need for CTPs that are inexpensive, easy to handle, and have the same printability as conventional PS plates. In particular, in recent years, there is an increasing expectation for a so-called processless plate that does not require a development process using a special agent and can be applied to a printing press having a direct imaging (DI) function.
[0003]
As such a processless plate, at present, it is substantially provided only for DI printing press applications, and a processless plate having sufficient performance as a general-purpose printing plate material is not provided.
[0004]
One reason why the processless plate is still insufficient for use as a general-purpose printing plate material is the low exposure visibility.
[0005]
In the DI printing machine, since the printing plate material is mounted on the plate cylinder, exposed for the image, and the printing plate material is not substantially inspected before printing is performed, even if the exposure visibility is low. Although it does not become a big problem, as a general-purpose printing plate material, even if it is a case where an image is formed by the CTP method, a plate inspection may be required, and exposure visibility is required.
[0006]
The processless plate is mainly a so-called thermal type that forms an image by infrared laser exposure, but the thermal type can be roughly divided into two types.
[0007]
One type of thermal type printing plate material is an ablation type, for example, by laminating two layers having different affinity for dampening water or ink used for printing on a substrate, The surface-side layer is ablated by laser exposure and completely removed. In this type, by changing the color tone of the above-mentioned two layers of visible light, it becomes possible to give exposure visible image quality. For example, printing with a configuration as disclosed in JP-T-2002-514984 A plate material can be mentioned. However, this type of printing plate material has a problem in that it is necessary to attach to the exposure apparatus a mechanism for completely sucking and removing the scattered matter on the ablated surface side layer, and the apparatus cost is greatly increased. In addition, since the energy required for exposure is relatively high, it is necessary to reduce the beam linear velocity during exposure (for example, to reduce the rotation speed of the exposure drum), which may reduce image formation productivity.
[0008]
Another type of thermal type printing plate material is an on-press development type. In this type, for example, two layers having different affinity for dampening water or ink used for printing are laminated on a substrate, and the adhesion between the surface side layer and the layer below it is improved by laser exposure. It is made to change and a part with weak adhesive force is removed on a printing machine. Various methods such as contact with a dampening water supply roller, dissolution or swelling by application of dampening water, contact with an ink roller, peeling by ink tack, contact with a blanket cylinder, etc. are used to remove a weakly adhesive part. Can be used.
[0009]
In the on-press development type printing plate, since at least a part of the surface layer is removed on the printing press, the layer to be removed is colored to prevent coloring contamination of dampening water and ink in the printing press. It is desirable not to. Therefore, it is difficult to provide good visible image properties.
[0010]
For example, Japanese Patent Application Laid-Open No. 11-240270 discloses a printing plate material imparted with visible image quality by providing a heat-sensitive layer containing an infrared absorbing dye whose optical density changes upon exposure. However, such infrared absorbing dyes generally fade when exposed to infrared light, but the color is not completely lost. For this reason, even when the exposed portion of the surface layer is removed, some colored matter is mixed / contaminated in the dampening water or ink of the printing press. Further, when the unexposed portion of the surface layer is removed, it is necessary to improve the contrast of the unexposed portion / exposed portion in order to improve the visibility, that is, to increase the coloring density of the unexposed portion. Visibility and printing press contamination are in conflicting performance.
[0011]
In the on-press development type printing plate material, JP-A-2001-322226 discloses a method for obtaining the contrast between the exposed portion and the unexposed portion without including a material that is substantially colored in the on-press developed layer. Then, using a lithographic printing plate provided with a recording layer mainly composed of heat-fusible particles and a porous layer having voids on a support, the heat-melting particles are heated and melted in the voids in the porous layer. An image recording method has been proposed in which a transparent and opaque contrast image is recorded. According to this method, it is possible to obtain a relatively good visible image quality without causing contamination of the printing press. However, since the light transmittance of the printing plate material is used for forming a contrast, the printing plate material alone is used. There was also a drawback that a constant visible image quality (for example, a difference in reflection density between an exposed area and an unexposed area) was not always obtained.
[0012]
[Problems to be solved by the invention]
An object of the present invention is to provide a plate inspection method that enables a clearer and more stable plate inspection after exposing a printing plate material having a specific transmission density to form an image.
[0013]
[Means for Solving the Problems]
The above object of the present invention has been achieved by the following constitutions.
[0014]
  1.Having at least a porous hydrophilic layer on the substrate and a layer containing a heat-meltable material having a melting point of 40 ° C. or higher and 300 ° C. or lower;After exposing a printing plate material having a transmission density of 0.05 or more and 0.5 or less, the printing plate material is placed on a colored member, and is irradiated with light from above the printing plate material.Light scattering is suppressed and light transmittance is improvedWith exposure sectionHigh light scatteringA plate inspection method for a printing plate material, wherein the plate inspection is performed while enhancing contrast with an unexposed portion.
[0015]
2. 2. The plate inspection method for a printing plate material according to 1 above, wherein the reflection density of the colored member is 0.5 or more and 3.0 or less.
[0016]
  3.Having at least a porous hydrophilic layer on the substrate and a layer containing a heat-meltable material having a melting point of 40 ° C. or higher and 300 ° C. or lower;After exposing a printing plate material having a transmission density of 0.05 or more and 0.5 or less, the printing plate material is placed on a reflective member and irradiated with light from above the printing plate material. MaterialLight scattering is suppressed and light transmittance is improvedWith exposure sectionHigh light scatteringA plate inspection method for a printing plate material, wherein the plate inspection is performed while enhancing contrast with an unexposed portion.
[0017]
4). 4. The plate inspection method for a printing plate material as described in 3 above, wherein the reflectance of the reflective member is 50% or more.
[0018]
5. The printing plate material of the type that forms an image by removing at least a part of a layer formed on the surface of the printing plate material after being attached to the plate cylinder of the printing press, 5. A plate inspection method for a printing plate material according to any one of 4 above.
[0019]
6). 6. The printing plate material according to 5 above, wherein the operation of removing at least part of the layer formed on the surface is performed by applying at least one of dampening water and ink to the surface of the printing plate material. Plate inspection method.
[0021]
The present invention will be described in more detail. According to the first and second aspects of the present invention, the difference in reflection density in the visible light region between the unexposed portion and the exposed portion of the printing plate material in which the light transmittance of the printing plate material as a whole changes by exposure is more emphasized. This is a plate inspection method for improving plate quality. The change of the light transmittance by exposure may be the case where the light transmittance is improved or decreased by the exposure. A method in which the transmission density of the printing plate material in the unexposed area is set to 0.05 or more and 0.5 or less, the exposed printing plate material is placed on a colored member, and light is applied from above the printing plate material. Thus, it is possible to enhance the difference in reflection density regardless of whether the light transmittance is improved or decreased by exposure. The reflection density of the colored member is preferably 0.5 or more, more preferably 1.0 or more, and further preferably 1.5 or more. The reflection density has no particular upper limit, but if it exceeds 3.0, the practicality is poor.
[0022]
In the inventions of claims 3 and 4, the light transmittance of the printing plate material as a whole changes by exposure, and the difference in reflectance in the visible light region between the unexposed portion and the exposed portion of the printing plate material is further emphasized. This is a plate inspection method for improving plate quality. The change of the light transmittance by exposure may be the case where the light transmittance is improved or decreased by the exposure. The transmission density of the printing plate material in the unexposed area is set to 0.05 or more and 0.5 or less, the exposed printing plate material is placed on a reflective member, and light is applied from above the printing plate material. By this method, it is possible to enhance the difference in reflectance even when the light transmittance is improved or decreased by exposure. The reflectivity of the reflective member is preferably 50% or more, more preferably 75% or more, and further preferably 90% or more and 100% or less.
[0023]
The plate inspection method of the invention of claims 5 to 7 is particularly suitable for an on-press development type printing plate material that is difficult to impart visible imageability, and particularly has at least a porous hydrophilic layer and a melting point on the substrate. Is a plate inspection method most suitable for a printing plate material having a layer (hereinafter, image forming layer) containing a heat-meltable material having a temperature of 40 ° C. or higher and 300 ° C. or lower.
[0024]
This type of printing plate material melts the heat-melting material in the image-forming layer upon exposure and penetrates into the porous hydrophilic layer, thereby blocking the light scattering and blocking light scattering. To improve the rate.
[0025]
By forming the heat-melting material into a fine particle form and using a binder having a refractive index different from that of the heat-melting material, the image-forming layer itself is highly light-scattering when not exposed, and the heat-melting material particles are exposed during exposure. By melting and integrating, the light scattering property is lowered, and it contributes to the improvement of the light transmittance by exposure of the printing plate material.
[0026]
Furthermore, the surface of the printing plate material is roughened to improve the light scattering property. After exposure, the image forming layer is melted and leveled, and the light scattering property is also lowered by smoothing the surface. It contributes to the improvement of the light transmittance by this exposure.
[0027]
Next, the printing plate material according to the present invention will be described.
[Base material]
As the base of the printing plate material according to the present invention, a known flexible material conventionally used as a base of a printing plate can be used as long as the transmission density is at least 0.5 or less. However, since the layer applied on the substrate in order to function as a printing plate also has a certain transmission density, the transmission density of the substrate is preferably 0.3 or less, and is substantially 0 or 0. More preferably, it is 1 or less. In general, a highly transparent plastic film is used.
[0028]
Examples of the plastic film include polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polycarbonate, polysulfone, polyphenylene oxide, and cellulose esters. In particular, polyethylene terephthalate and polyethylene naphthalate are preferable. These plastic films are preferably subjected to easy adhesion treatment or undercoat layer coating on the coated surface in order to improve adhesion with the coated layer. Examples of the easy adhesion treatment include corona discharge treatment, flame treatment, plasma treatment, and ultraviolet irradiation treatment. Examples of the undercoat layer include a layer containing gelatin or latex. Moreover, the antistatic layer containing a well-known tin sol etc. may be formed, and the well-known backcoat layer may be formed. However, it is necessary that the transmission density of the functional coating layer itself be considered so that the transmission density as the printing plate material falls within the scope of the present invention. The film may be subjected to a known treatment for improving strength and improving dimensional stability.
[0029]
[Hydrophilic layer]
Examples of the material used for the hydrophilic layer of the printing plate material according to the present invention include the following.
[0030]
[Material for forming hydrophilic layer matrix]
As a material for forming the hydrophilic layer matrix, a metal oxide is preferable. The metal oxide preferably contains metal oxide fine particles. Examples thereof include colloidal silica, alumina sol, titania sol, and other metal oxide sols. The form of the metal oxide fine particles may be spherical, needle-like, feather-like, or any other form. The average particle diameter is preferably 3 to 100 nm, and several kinds of metal oxide fine particles having different average particle diameters can be used in combination. The surface of the particles may be surface treated.
[0031]
The metal oxide fine particles can be used as a binder by utilizing the film forming property. The decrease in hydrophilicity is less than when an organic binder is used, and it is suitable for use in a hydrophilic layer.
[0032]
Among the above, colloidal silica can be preferably used in the present invention. Colloidal silica has the advantage of high film-forming properties even under relatively low temperature drying conditions, and can provide good strength.
[0033]
The colloidal silica preferably includes necklace-like colloidal silica, which will be described later, and fine particle colloidal silica having an average particle size of 20 nm or less, and the colloidal silica preferably exhibits alkalinity as a colloidal solution.
[0034]
The necklace-like colloidal silica used in the present invention is a general term for an aqueous dispersion of spherical silica whose primary particle diameter is on the order of nm. The necklace-like colloidal silica used in the present invention means “pearl necklace-like” colloidal silica in which spherical colloidal silica having a primary particle diameter of 10 to 50 nm is bonded to a length of 50 to 400 nm. The pearl necklace shape (that is, the pearl necklace shape) means that the image in a state in which the silica particles of colloidal silica are connected and connected has a shape like a pearl necklace. The bond between the silica particles constituting the necklace-shaped colloidal silica is presumed to be —Si—O—Si— in which —SiOH groups present on the surface of the silica particles are dehydrated. Specific examples of the colloidal silica in the form of necklace include “Snowtex-PS” series manufactured by Nissan Chemical Industries, Ltd.
[0035]
Product names include “Snowtex-PS-S (average particle size in the connected state is about 110 nm)”, “Snowtex-PS-M (average particle size in the connected state is about 120 nm)” and “Snowtex- PS-L (the average particle size in the connected state is about 170 nm) ", and acidic products corresponding to these are" Snowtex-PS-SO "," Snowtex-PS-MO "and “Snowtex-PS-LO”.
[0036]
By adding necklace-like colloidal silica, it becomes possible to maintain the strength while ensuring the porosity of the layer, and it can be preferably used as a porous material for the hydrophilic layer matrix.
[0037]
Among these, when “Snowtex PS-S”, “Snowtex PS-M”, and “Snowtex PS-L”, which are alkaline, are used, the strength of the hydrophilic layer is improved and the number of printed sheets is large. However, it is particularly preferable because the occurrence of soiling is suppressed.
[0038]
Further, it is known that the colloidal silica has a stronger binding force as the particle diameter is smaller, and it is preferable to use colloidal silica having an average particle diameter of 20 nm or less in the present invention, and more preferably 3 to 15 nm. preferable. In addition, as described above, alkaline colloidal silica is particularly preferable because alkaline colloidal silica has a high effect of suppressing the occurrence of soiling.
[0039]
Alkaline colloidal silica having an average particle size within this range includes “Snowtex-20 (particle size 10-20 nm)”, “Snowtex-30 (particle size 10-20 nm)”, “Snowtex” manufactured by Nissan Chemical Co., Ltd. -40 (particle diameter 10-20 nm) "," Snowtex-N (particle diameter 10-20 nm) "," Snowtex-S (particle diameter 8-11 nm) "," Snowtex-XS (particle diameter 4-6 nm) ) ".
[0040]
Colloidal silica having an average particle size of 20 nm or less is particularly preferable because it can be further improved in strength while maintaining the porous property of the layer when used in combination with the aforementioned necklace-like colloidal silica.
[0041]
The ratio of colloidal silica having an average particle diameter of 20 nm or less to necklace-like colloidal silica is preferably 95: 5 to 5:95, more preferably 70:30 to 20:80, and still more preferably 60:40 to 30:70.
[0042]
As the porous material of the hydrophilic layer matrix of the present invention, porous metal oxide particles having a particle size of less than 1 μm can be contained. As the porous metal oxide particles, porous silica, porous aluminosilicate particles, or zeolite particles described later can be preferably used.
[0043]
[Porous silica particles or porous aluminosilicate particles]
The porous silica particles are generally produced by a wet method or a dry method. In the wet method, it can be obtained by drying and pulverizing a gel obtained by neutralizing an aqueous silicate solution, or by pulverizing a precipitate deposited after neutralization. In the dry method, silicon tetrachloride is burned together with hydrogen and oxygen to obtain silica. These particles can be controlled in porosity and particle size by adjusting the production conditions. As the porous silica particles, those obtained from a wet gel are particularly preferable.
[0044]
The porous aluminosilicate particles are produced, for example, by the method described in JP-A-10-71764. That is, amorphous composite particles synthesized by hydrolysis using aluminum alkoxide and silicon alkoxide as main components. The ratio of alumina to silica in the particles can be synthesized in the range of 1: 4 to 4: 1. In addition, those produced as composite particles of three or more components by adding an alkoxide of another metal during production can also be used in the present invention. These composite particles can also control the porosity and particle size by adjusting the production conditions.
[0045]
The porosity of the particles is preferably 0.5 ml / g or more in terms of pore volume, more preferably 0.8 ml / g or more, and 1.0 to 2.5 ml / g or less. Further preferred.
[0046]
The pore volume is closely related to the water retention of the coating film. The larger the pore volume, the better the water retention and the less smudged during printing, and the greater the water volume latitude, but greater than 2.5 ml / g. Then, since the particles themselves become very brittle, the durability of the coating film decreases. When the pore volume is less than 0.5 ml / g, the printing performance may be slightly insufficient.
[0047]
[Zeolite particles]
Zeolite is a crystalline aluminosilicate and is a porous body having regular three-dimensional network voids having a pore diameter of 0.3 to 1 nm. The general formula combining natural and synthetic zeolite is expressed as follows:
[0048]
(M¹, M² _1/2)_m(Al_mSi_nO₂ ^{(m + n)}XH₂O
Where M¹, M²Is an exchangeable cation, and M¹Li⁺, Na⁺, K⁺, Tl⁺, Me_FourN⁺(TMA), Et_FourN⁺(TEA), Pr_FourN⁺(TPA), C₇H₁₅N²⁺, C₈H₁₆N⁺Etc., M²Is Ca²⁺, Mg²⁺, Ba²⁺, Sr²⁺, C₈H₁₈N_{twenty two} ⁺Etc. Further, n ≧ m, and the value of m / n, that is, the Al / Si ratio is 1 or less. The higher the Al / Si ratio, the greater the amount of exchangeable cations, and thus the higher the polarity and therefore the higher the hydrophilicity. A preferable Al / Si ratio is 0.4 to 1.0, and more preferably 0.8 to 1.0. x represents an integer.
[0049]
The zeolite particles used in the present invention are preferably synthetic zeolites having a stable Al / Si ratio and a relatively sharp particle size distribution, such as zeolite A: Na.₁₂(Al₁₂Si₁₂O₄₈27H₂O: Al / Si ratio 1.0, zeolite X: Na₈₆(Al₈₆Si₁₀₆O₃₈₄) ・ 264H₂O: Al / Si ratio 0.811, zeolite Y: Na₅₆(Al₅₆Si₁₃₆O₃₈₄) ・ 250H₂O; Al / Si ratio 0.412 and the like.
[0050]
By containing highly hydrophilic porous particles having an Al / Si ratio of 0.4 to 1.0, the hydrophilicity of the hydrophilic layer itself is greatly improved, it is difficult to get dirty during printing, and the water latitude is widened. In addition, the dirt on the fingerprint marks is greatly improved. When the Al / Si ratio is less than 0.4, the hydrophilicity is insufficient, and the effect of improving the performance becomes small.
[0051]
Further, the hydrophilic layer matrix of the printing plate material according to the present invention can contain layered mineral particles. Examples of the layered mineral particles include layered minerals such as kaolinite, halloysite, talc, smectite (montmorillonite, beidellite, hectorite, sabonite, etc.), vermiculite, mica (mica), chlorite, hydrotalcite, layered polysilicate ( Kanemite, macatite, ialite, magadiite, kenyaite, etc.). Among them, it is considered that the higher the charge density of the unit layer (unit layer), the higher the polarity and the higher the hydrophilicity. The charge density is preferably 0.25 or more, more preferably 0.6 or more. Examples of the layered mineral having such a charge density include smectite (charge density 0.25 to 0.6; negative charge), vermiculite (charge density 0.6 to 0.9; negative charge) and the like. In particular, synthetic fluoromica is preferable because it can be obtained with stable quality such as particle size. Among the synthetic fluorine mica, those that are swellable are preferable, and those that are free swell are more preferable.
[0052]
Also used are intercalation compounds of the above-mentioned layered minerals (pillar crystals, etc.), those subjected to ion exchange treatment, and those subjected to surface treatment (silane coupling treatment, compounding treatment with organic binder, etc.) can do.
[0053]
As the size of the flat lamellar mineral particles, the average particle diameter (maximum length of the particles) is less than 1 μm in the state of being contained in the layer (including the case where the swelling process and the dispersion peeling process have been performed). The aspect ratio is preferably 50 or more. When the particle size is in the above range, the continuity and flexibility in the planar direction, which are the characteristics of the thin layered particles, are imparted to the coating film, and it is difficult for cracks to occur, and a tough coating film can be obtained in a dry state. Moreover, in the coating liquid containing many particulate matters, sedimentation of particulate matter can be suppressed by the thickening effect of the layered mineral. When the particle diameter is larger than the above range, the coating film may be non-uniform, and the strength may be locally reduced. On the other hand, when the aspect ratio is not more than the above range, the number of tabular grains with respect to the addition amount is reduced, the viscosity is insufficient, and the effect of suppressing sedimentation of the particulate matter is reduced.
[0054]
The content of the layered mineral particles is preferably 0.1 to 30% by mass, and more preferably 1 to 10% by mass based on the entire layer. In particular, swellable synthetic fluorinated mica and smectite are preferable because they are effective even when added in a small amount. The layered mineral particles may be added as a powder to the coating solution, but in order to obtain a good degree of dispersion even with a simple preparation method (no need for a dispersion step such as media dispersion), the layered mineral particles are used alone. It is preferable that the gel swollen in water is prepared and then added to the coating solution.
[0055]
A silicate aqueous solution can also be used as another additive material in the hydrophilic layer matrix of the present invention. Alkali metal silicates such as silicate Na, silicate K, and silicate Li are preferred, and their SiO₂/ M₂The O ratio is preferably selected so that the pH of the entire coating solution when the silicate is added does not exceed 13 in order to prevent dissolution of the inorganic particles.
[0056]
Further, an inorganic polymer or an organic-inorganic hybrid polymer using a metal alkoxide by a so-called sol-gel method can also be used. The formation of an inorganic polymer or an organic-inorganic hybrid polymer by the sol-gel method is described in, for example, “Application of the sol-gel method” (Sakuo Sakuo / Published by Agne Jofusha) or cited in this book. Known methods described in the published literature can be used.
[0057]
Moreover, you may contain water-soluble resin or water-dispersible resin. Examples of water-soluble resins and water-dispersible resins include polysaccharides, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyethylene glycol (PEG), polyvinyl ether, styrene-butadiene copolymers, and conjugated diene systems of methyl methacrylate-butadiene copolymers. Examples thereof include resins such as polymer latex, acrylic polymer latex, vinyl polymer latex, polyacrylamide, and polyvinyl pyrrolidone. In the present invention, it is preferable to use a polysaccharide as the water-soluble resin.
[0058]
As polysaccharides, starches, celluloses, polyuronic acids, pullulans and the like can be used, but cellulose derivatives such as methyl cellulose salts, carboxymethyl cellulose salts, hydroxyethyl cellulose salts are particularly preferable, and sodium salts and ammonium salts of carboxymethyl cellulose are preferable. More preferred.
[0059]
This is because the effect of forming the surface shape of the hydrophilic layer in a preferable state can be obtained by including the polysaccharide in the hydrophilic layer.
[0060]
The surface of the hydrophilic layer preferably has a concavo-convex structure with a pitch of 0.1 to 20 μm like the aluminum grain of the PS plate, and this concavo-convex improves water retention and image area retention.
[0061]
Such a concavo-convex structure can be formed by adding an appropriate amount of a filler having an appropriate particle size to the hydrophilic layer matrix. However, the above-mentioned alkaline colloidal silica and the above-mentioned water-soluble solution are added to the hydrophilic layer coating solution. It is preferable that a structure having better printability can be obtained by forming a phase separation when the hydrophilic polysaccharide is applied and dried.
[0062]
The shape of the concavo-convex structure (such as pitch and surface roughness) is the type and amount of alkaline colloidal silica, the type and amount of water-soluble polysaccharides, the type and amount of other additives, the solid content concentration of the coating solution, and the wet film. The thickness and drying conditions can be appropriately controlled.
[0063]
The water-soluble resin added to the hydrophilic matrix in the present invention is preferably present in a state where at least a part thereof is water-soluble and can be eluted in water. This is because even if it is a water-soluble material, when it is cross-linked by a cross-linking agent or the like and becomes insoluble in water, its hydrophilicity is lowered and printability may be deteriorated.
[0064]
Further, a cationic resin may be contained, and as the cationic resin, polyalkylene polyamines such as polyethylene amine and polypropylene polyamine or derivatives thereof, an acrylic resin having a tertiary amino group or a quaternary ammonium group, And diacrylamine. The cationic resin may be added in the form of fine particles. Examples thereof include a cationic microgel described in JP-A-6-161101.
[0065]
The hydrophilic layer coating solution of the present invention may contain a water-soluble surfactant for the purpose of improving coating properties. A surfactant such as Si-based or F-based can be used, but it is particularly preferable to use a surfactant containing Si element because there is no fear of causing printing stains. The content of the surfactant is preferably 0.01 to 3% by mass, more preferably 0.03 to 1% by mass, based on the entire hydrophilic layer (solid content as the coating solution).
[0066]
The hydrophilic layer of the present invention can contain a phosphate. In the present invention, since the hydrophilic layer coating solution is preferably alkaline, the phosphate is preferably added as trisodium phosphate or disodium hydrogen phosphate. By adding phosphate, the effect of improving the mesh opening at the time of printing can be obtained. The addition amount of phosphate is preferably 0.1 to 5% by mass, and more preferably 0.5 to 2% by mass as an effective amount excluding hydrate.
[0067]
Furthermore, the photothermal conversion raw material mentioned later can also be contained. As the photothermal conversion material, in the case of a particulate material, the particle size is preferably less than 1 μm.
[0068]
[Particles coated with an inorganic or inorganic material having a particle size of 1 μm or more]
In order to appropriately control the surface shape, the hydrophilic layer can contain particles coated with an inorganic or inorganic material having a particle size of 1 μm or more. As the inorganic particles, known metal oxide particles such as silica, alumina, titania, zirconia and the like can be used, but in order to suppress sedimentation in the coating solution, porous metal oxide particles can be used. preferable.
[0069]
As the porous metal oxide particles, the aforementioned porous silica particles and porous aluminosilicate particles can be preferably used.
[0070]
Examples of the particles coated with an inorganic material include particles obtained by coating a core material of organic particles such as PMMA and polystyrene with inorganic particles having a smaller particle diameter than the core material particles. The particle size of the inorganic particles is preferably about 1/10 to 1/100 of the core particles. As the inorganic particles, known metal oxide particles such as silica, alumina, titania, zirconia, etc. can be used.
[0071]
As the coating method, various known methods can be used, but the core material particles and the coating material particles are collided at high speed in the air like a hybridizer to cause the coating material particles to bite into the surface of the core material particles. A dry coating method of fixing and coating can be preferably used.
[0072]
Moreover, the particle | grains which carried out the metal plating of the core material of an organic particle can also be used. Examples of such particles include “Micropearl AU” manufactured by Sekisui Chemical Co., Ltd., in which resin particles are plated with gold.
[0073]
The particle size of the particles coated with an inorganic or inorganic material having a particle size of 1 μm or more is preferably 1 to 10 μm, more preferably 1.5 to 8 μm, and even more preferably 2 to 6 μm.
[0074]
If the particle diameter of the particles coated with an inorganic or inorganic material having a particle diameter of 1 μm or more exceeds 10 μm, there is a concern that the resolution of image formation is reduced and the blanket stain is deteriorated.
[0075]
The addition amount of the particles coated with an inorganic or inorganic material having a particle size of 1 μm or more is preferably 1 to 50% by mass, more preferably 5 to 40% by mass based on the entire hydrophilic layer.
[0076]
The hydrophilic layer as a whole preferably has a low content ratio of materials containing carbon such as organic resin and carbon black in order to improve hydrophilicity, and the total of these materials is preferably less than 9% by mass. More preferably, it is less than 5 mass%.
[0077]
[Underlayer]
When a lower layer is provided, the same material as the hydrophilic layer can be used as the material used for the lower layer.
[0078]
However, the lower layer is less advantageous in that it is porous, and the nonporous material improves the coating strength, so the content of the porous material of the hydrophilic matrix is higher than that of the hydrophilic layer. Is preferably less, more preferably not contained.
[0079]
In order to appropriately control the surface shape of the lower layer, particles coated with an inorganic or inorganic material having a particle size of 1 μm or more can be contained. The addition amount of particles having a particle diameter of 1 μm or more is preferably 1 to 50% by mass, more preferably 5 to 40% by mass based on the entire lower layer.
[0080]
Similarly to the hydrophilic layer as the entire lower layer, a low content ratio of materials containing carbon such as organic resin and carbon black is preferable for improving hydrophilicity, and the total of these materials is less than 9% by mass. It is preferable that it is less than 5% by mass.
[0081]
[Photothermal conversion material]
The hydrophilic layer, the lower layer, the backcoat layer, the layer formed on the surface of the plate cylinder, and the other layers provided in the present invention can contain a photothermal conversion material.
[0082]
The following materials can be added as the photothermal conversion material.
General infrared absorbing dyes such as cyanine dyes, croconium dyes, polymethine dyes, azurenium dyes, squalium dyes, thiopyrylium dyes, naphthoquinone dyes, anthraquinone dyes, organic compounds such as phthalocyanine dyes and naphthalocyanine dyes , Azo-based, thioamide-based, dithiol-based, and indoaniline-based organometallic complexes. Specifically, JP-A-63-139191, JP-A-64-33547, JP-A-1-160683, JP-A-1-280750, JP-A-1-293342, JP-A-2-2074, Kaihei 3-26593, JP-A-3-30991, JP-A-3-34891, JP-A-3-36093, JP-A-3-36094, JP-A-3-36095, JP-A-3-42281, JP-A-3-42281 Examples thereof include compounds described in JP-A-3-97589, JP-A-3-103476, and the like. These can be used alone or in combination of two or more.
[0083]
Examples of the pigment include carbon, graphite, metal, metal oxide and the like. As carbon, furnace black or acetylene black is particularly preferable. The particle size (d50) is preferably 100 nm or less, and more preferably 50 nm or less.
[0084]
As the graphite, fine particles having a particle size of 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less can be used.
[0085]
As the metal, any metal can be used as long as the particle diameter is 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less. The shape may be any shape such as a spherical shape, a piece shape, or a needle shape. Colloidal metal fine particles (Ag, Au, etc.) are particularly preferable.
[0086]
As the metal oxide, a material that is black in the visible light region, or a material that has conductivity or is a semiconductor can be used.
[0087]
As the former, black iron oxide (Fe_ThreeO_Four) And black composite metal oxides containing two or more of the aforementioned metals.
[0088]
Examples of the latter include SnO doped with Sb, for example.₂(ATO), In with Sn added₂O_Three(ITO), TiO₂TiO₂And TiO (titanium oxynitride, generally titanium black) reduced. These metal oxides can also be used as a core material (BaSO_FourTiO₂, 9Al₂O_Three・ 2B₂O, K₂O · nTiO₂Etc.) can also be used. These particle sizes are 0.5 μm or less, preferably 100 nm or less, and more preferably 50 nm or less.
[0089]
Among these photothermal conversion materials, black composite metal oxides containing two or more metals are more preferable materials.
[0090]
Specifically, it is a composite metal oxide composed of two or more metals selected from Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sb, and Ba. These are disclosed by methods disclosed in JP-A-8-27393, JP-A-9-25126, JP-A-9-237570, JP-A-9-241529, JP-A-10-231441, and the like. Can be manufactured.
[0091]
The composite metal oxide used in the present invention is particularly preferably a Cu-Cr-Mn-based or Cu-Fe-Mn-based composite metal oxide. In the case of a Cu—Cr—Mn system, it is preferable to perform the treatment disclosed in JP-A-8-27393 in order to reduce the elution of hexavalent chromium. These composite metal oxides are colored with respect to the amount added, that is, they have good photothermal conversion efficiency.
[0092]
These composite metal oxides preferably have an average primary particle size of 1 μm or less, and more preferably have an average primary particle size in the range of 0.01 to 0.5 μm. When the average primary particle diameter is 1 μm or less, the photothermal conversion ability with respect to the addition amount becomes better, and when the average primary particle diameter is within the range of 0.01 to 0.5 μm, the photothermal conversion ability with respect to the addition amount is obtained. Better. However, the photothermal conversion ability with respect to the addition amount is greatly affected by the degree of dispersion of the particles, and the better the dispersion, the better. Therefore, it is preferable to disperse these composite metal oxide particles by a known method separately before adding them to the layer coating solution to prepare a dispersion (paste). An average primary particle size of less than 0.01 is not preferable because dispersion becomes difficult. A dispersing agent can be appropriately used for the dispersion. The addition amount of the dispersant is preferably 0.01 to 5% by mass, and more preferably 0.1 to 2% by mass with respect to the composite metal oxide particles.
[0093]
As addition amount of these composite metal oxides, it is 0.1-50 mass% with respect to a hydrophilic layer or a lower layer, 1-30 mass% is preferable, and 3-25 mass% is more preferable.
[0094]
[Image-forming functional layer containing heat-fusible and / or heat-fusible fine particles]
The printing plate material according to the present invention can have an image-forming functional layer containing heat-meltable and / or heat-fusible fine particles, and the image-forming functional layer can contain the following materials.
[0095]
[Hot-melting fine particles]
The heat-meltable fine particles used in the present invention are fine particles formed of a material that has a low viscosity when melted, and is generally classified as a wax, among thermoplastic materials. The physical properties are preferably a softening point of 40 ° C. or higher and 120 ° C. or lower, a melting point of 60 ° C. or higher and 150 ° C. or lower, more preferably a softening point of 40 ° C. or higher and 100 ° C. or lower, and a melting point of 60 ° C. or higher and 120 ° C. or lower. When the melting point is less than 60 ° C., storage stability is a problem, and when the melting point is higher than 300 ° C., ink deposition sensitivity is lowered.
[0096]
Usable materials include paraffin, polyolefin, polyethylene wax, microcrystalline wax, fatty acid wax and the like. These have a molecular weight of about 800 to 10,000. In order to facilitate emulsification, these waxes can be oxidized to introduce polar groups such as hydroxyl groups, ester groups, carboxyl groups, aldehyde groups, and peroxide groups. Furthermore, in order to lower the softening point and improve the workability, these waxes are stearamide, linolenamide, laurylamide, myristamide, hardened beef fatty acid amide, palmitoamide, oleic acid amide, rice sugar fatty acid amide, palm fatty acid amide. Alternatively, methylolated products of these fatty acid amides, methylene bisstellaramide, ethylene bisstellaramide, and the like can be added. Coumarone-indene resin, rosin-modified phenol resin, terpene-modified phenol resin, xylene resin, ketone resin, acrylic resin, ionomer, and copolymers of these resins can also be used.
[0097]
Among these, it is preferable to contain any of polyethylene, microcrystalline, fatty acid ester, and fatty acid. Since these materials have a relatively low melting point and a low melt viscosity, high-sensitivity image formation can be performed. In addition, since these materials have lubricity, damage when a shearing force is applied to the surface of the printing plate material is reduced, and resistance to printing stains due to scratches or the like is improved.
[0098]
The heat-meltable fine particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle size is smaller than 0.01 μm, when the coating liquid for the layer containing the heat-meltable fine particles is applied onto the porous hydrophilic layer described later, the heat-meltable fine particles are not removed from the pores of the hydrophilic layer. It becomes easy to enter inside or into the gaps between fine irregularities on the surface of the hydrophilic layer, and the on-press development becomes insufficient, which may cause scumming. When the average particle size of the heat-meltable fine particles is larger than 10 μm, the resolution is lowered.
[0099]
Further, the composition of the heat-meltable fine particles may vary continuously between the inside and the surface layer, or may be coated with a different material. As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used. As content of the heat-meltable microparticles | fine-particles in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is more preferable.
[0100]
[Heat-adhesive fine particles]
Examples of the heat-fusible fine particles of the present invention include thermoplastic hydrophobic polymer fine particles, and there is no specific upper limit for the softening temperature of the thermoplastic hydrophobic polymer fine particles, but the temperature is high. It is preferably lower than the decomposition temperature of the coalesced fine particles. The mass average molecular weight (Mw) of the polymer is preferably in the range of 10,000 to 1,000,000.
[0101]
Specific examples of the polymer constituting the polymer particles include, for example, diene (co) polymers such as polypropylene, polybutadiene, polyisoprene and ethylene-butadiene copolymer, styrene-butadiene copolymer, Synthetic rubbers such as methyl methacrylate-butadiene copolymer, acrylonitrile-butadiene copolymer, polymethyl methacrylate, methyl methacrylate- (2-ethylhexyl acrylate) copolymer, methyl methacrylate-methacrylic acid copolymer, methyl acrylate- ( N-methylolacrylamide) copolymer, (meth) acrylic acid ester such as polyacrylonitrile, (meth) acrylic acid (co) polymer, polyvinyl acetate, vinyl acetate-vinyl propionate copolymer, vinyl acetate-ethylene copolymer Vinyl etc. of polymers Ester (co) polymer, vinyl acetate - (2-ethylhexyl acrylate) copolymers, polyvinyl chloride, polyvinylidene chloride, polystyrene and copolymers thereof.
[0102]
The polymer polymer fine particles may be composed of a polymer polymer polymerized by any known method such as emulsion polymerization, suspension polymerization, solution polymerization, and gas phase polymerization. As a method of microparticulating a polymer polymer polymerized by a solution polymerization method or a gas phase polymerization method, a method of spraying a solution in an organic solvent of the polymer polymer into an inert gas and drying to form particles, Examples thereof include a method in which a high molecular weight polymer is dissolved in a water-immiscible organic solvent, this solution is dispersed in water or an aqueous medium, and the organic solvent is distilled off to form fine particles. In any of the methods, a surfactant, such as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, polyethylene glycol, or a water-soluble resin, such as polyvinyl alcohol, is used as a dispersant or stabilizer in polymerization or micronization as necessary. May be used.
[0103]
The heat-fusible fine particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle size is smaller than 0.01 μm, when the coating liquid for the layer containing the heat-fusible fine particles is applied onto the porous hydrophilic layer described later, the heat-fusible fine particles It becomes easy to get into the pores or into the gaps between the fine irregularities on the surface of the hydrophilic layer, and the on-press development becomes insufficient, resulting in fear of soiling. When the average particle size of the heat-fusible fine particles is larger than 10 μm, the resolution is lowered.
[0104]
Moreover, the composition of the heat fusible particles may be continuously changed between the inside and the surface layer, or may be coated with a different material.
[0105]
As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used.
The content of the heat-fusible fine particles in the layer is preferably 1 to 90% by mass, and more preferably 5 to 80% by mass of the entire layer.
[0106]
[Water-soluble material]
The image-forming functional layer containing the heat-fusible and / or heat-fusible fine particles of the present invention can further contain a water-soluble material. By including the water-soluble material, when the image forming functional layer in the unexposed area is removed using dampening water or ink on the printing press, the removability can be improved.
[0107]
As the water-soluble material, the water-soluble resins mentioned as materials that can be contained in the hydrophilic layer can also be used. However, as the image forming functional layer of the present invention, it is preferable to use saccharides, particularly oligosaccharides. Is preferred.
[0108]
Since the oligosaccharide dissolves quickly in water, the removal of the image forming functional layer in the unexposed area on the printing apparatus becomes very quick, and the normal PS plate printing operation is unaware of the special removal operation. Can be removed by printing in the same manner as in the above, and printing waste paper does not increase.
[0109]
In addition, the oligosaccharide can maintain good printability of the hydrophilic layer without concern for lowering the hydrophilicity of the hydrophilic layer.
[0110]
An oligosaccharide is a crystalline substance that is soluble in water and generally has a sweet taste, and is obtained by dehydrating and condensing several monosaccharides by glycosidic bonds. Oligosaccharide is a kind of o-glycoside with sugar as aglycone, so it is easily hydrolyzed with acid to produce monosaccharide, and disaccharide, trisaccharide, tetrasaccharide, pentasaccharide, etc. depending on the number of molecules of monosaccharide produced are categorized. The oligosaccharide in the present invention refers to those from disaccharide to decasaccharide.
[0111]
These oligosaccharides are roughly classified into reducing oligosaccharides and non-reducing oligosaccharides depending on the presence or absence of a reducing group, and are composed of homooligosaccharides composed of a single monosaccharide and two or more types of monosaccharides. It is also classified as a hetero-oligosaccharide.
[0112]
Oligosaccharides exist naturally as free or glycosides and can also be obtained by partial hydrolysis of polysaccharides with acids or enzymes. Various oligosaccharides are also generated by glycosyl transfer by other enzymes.
[0113]
Oligosaccharides often exist as hydrates in a normal atmosphere. In addition, hydrates and anhydrides have different melting points, and examples are as shown in Table 1.
[0114]
[Table 1]

[0115]
In the present invention, it is preferable to coat and form a saccharide-containing layer with an aqueous solution. Therefore, when the oligosaccharide is formed from an aqueous solution, if the oligosaccharide present in the layer is an oligosaccharide that forms a hydrate, its melting point. Is considered to be the melting point of the hydrate. Thus, since it has a relatively low melting point, the oligosaccharide also melts in the temperature range in which the heat-fusible fine particles melt and the temperature range in which the heat-fusible fine particles fuse, Image formation such as melt penetration into the hydrophilic layer and fusion of heat-fusible fine particles is not hindered.
[0116]
Among oligosaccharides, trehalose, which is relatively high in purity, is commercially available at low cost, and despite its high solubility in water, its hygroscopicity is very low, and it is easy to develop and preserve on-machine. The sex is very good.
[0117]
In addition, when oligosaccharide hydrate is melted by heat and solidified after removing the hydrate (for a short time after solidification), it becomes an anhydrous crystal. It is characteristic that it is higher than 100 ° C. This means that the exposed portion immediately after being melted by infrared exposure and re-solidified is in a state of being difficult to melt at a high melting point, and has the effect of making it difficult to cause image defects during exposure such as banding. As content of the oligosaccharide in a layer, 1-90 mass% of the whole layer is preferable, and 10-80 mass% is more preferable.
[0118]
[Infrared printing plate material image formation]
Image formation of a printing plate material that can be preferably used in the present invention can be performed by heat, but it is particularly preferably performed by exposure with an infrared laser.
[0119]
More specifically, the exposure according to the present invention is preferably scanning exposure using a laser that emits light in the infrared and / or near infrared region, that is, in the wavelength range of 700 to 1500 nm. A gas laser may be used as the laser, but it is particularly preferable to use a semiconductor laser that emits light in the near infrared region.
[0120]
As an apparatus suitable for scanning exposure according to the present invention, any apparatus can be used as long as it can form an image on the surface of a printing plate material in accordance with an image signal from a computer using the semiconductor laser. Good.
[0121]
In general,
(1) A method of exposing the entire surface of the printing plate material by performing two-dimensional scanning using one or a plurality of laser beams on the printing plate material held by the plate-like holding mechanism,
(2) The circumferential direction of the cylinder (main scanning direction) using one or a plurality of laser beams from the inside of the cylinder to the printing plate material held along the cylindrical surface inside the fixed cylindrical holding mechanism ), Scanning the entire surface of the printing plate material by moving it in a direction perpendicular to the circumferential direction (sub-scanning direction),
(3) A printing plate material held on the surface of a cylindrical drum that rotates about an axis as a rotating body is rotated in the circumferential direction (main scanning direction) by rotating the drum using one or a plurality of laser beams from the outside of the cylinder. ) And moving in the direction perpendicular to the circumferential direction (sub-scanning direction) to expose the entire surface of the printing plate material.
[0122]
In the present invention, the scanning exposure method (3) is particularly preferable, and the exposure method (3) is used particularly in an apparatus that performs exposure on a printing apparatus.
[0123]
【Example】
Example 1
(Substrate 1-3)
a. Base material 1
An undercoat layer was formed on both sides of a transparent PET film having a thickness of 175 μm by the following procedure to obtain a substrate 1. The transmission density of the substrate 1 was measured by a black and white density (Visual) using a Macbeth densitometer: TD904, and found to be 0.04.
[0124]
1) First undercoat layer
After the corona discharge treatment is applied to the coated surface of the PET base material, a coating solution having the following composition is coated with a wire bar in an atmosphere of 20 ° C. and a relative humidity of 55% so that the film thickness after drying is 0.4 μm. did. Thereafter, drying was performed at 140 ° C. for 2 minutes.
[0125]
<First undercoat layer coating solution>

Distilled water was added to make 1000 ml, and a coating solution was obtained.
[0126]
2) Second undercoat layer
After the surface of the film having the first undercoat layer formed thereon is subjected to a corona discharge treatment, a coating solution having the following composition is dried by an air knife method in an atmosphere of 35 ° C. and a relative humidity of 22% so that the thickness after drying is 0 It was applied so as to be 1 μm. Thereafter, drying was performed at 140 ° C. for 2 minutes.
[0127]
<Second undercoat layer coating solution>
9.6 g of gelatin
Surfactant (A) 0.4g
Hardener (b) 0.1g
[0128]
[Chemical 1]

[0129]
b. Base material 2
A base material 2 was obtained in the same manner as the base material 1 except that a PET film transparently colored in blue for a medical sensitive material having a thickness of 175 μm was used. The transmission density of the substrate 2 was 0.17.
[0130]
c. Base material 3
A substrate 3 was obtained in the same manner as the substrate 1 except that a white PET film having a thickness of 175 μm was used. The transmission density of the substrate 3 was 0.42.
[0131]
(Preparation of coating solution)
a. Preparation of hydrophilic layer coating solution
The raw materials having the composition shown in Table 2 were sufficiently stirred and mixed using a homogenizer, and then filtered to prepare a coating solution for the hydrophilic layer (numerical values not indicated in the table indicate parts by mass).
[0132]
[Table 2]

[0133]
b. Preparation of coating solution for image forming layer
After sufficiently mixing and stirring the compositions shown in Table 3, the mixture was filtered to prepare a coating solution for an image forming layer (numerical values not shown in the table indicate parts by mass).
[0134]
[Table 3]

[0135]
(Preparation of printing plate material)
Using the base material shown in Table 4, the hydrophilic layer and the image forming layer were coated with a wire bar so as to have the dry weight shown in Table 4, and printing plate materials 1 to 5 were produced. The coating and drying conditions for the hydrophilic layer were 80 ° C. for 3 minutes, and aging was performed at 60 ° C. for 24 hours when the hydrophilic layer was formed. Next, an image forming layer was applied. The drying conditions after application of the image forming layer were 55 ° C. for 3 minutes. The transmission density of each printing plate material was measured and shown in Table 4.
[0136]
[Table 4]

[0137]
(Image formation)
Image formation was performed by infrared laser exposure. A laser beam having a wavelength of 830 nm and a spot diameter of about 18 μm is used for exposure, and the focus of the laser beam is adjusted to the surface of the printing plate materials 1 to 5, and the exposure energy is 300 mj / cm.²Under these conditions, an image was formed with 2400 dpi (dpi represents 1 inch, that is, the number of dots per 2.54 cm) and 175 lines. As an image for evaluation, a solid image, a dot image of 1 to 99%, and a line & space image by vertical, horizontal, and diagonal lines were used.
[0138]
(Printing method, printing evaluation)
Using DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd. as a printing machine, the exposed printing plate materials 1 to 5 are attached to the plate cylinder, coated paper, dampening water: Astro Mark 3 (manufactured by Nikken Chemical Laboratory) 2 Printing was performed using mass%, ink (Toyo King High Echo M Red manufactured by Toyo Ink Co., Ltd.). The printing start sequence was the PS printing sequence, and no special on-press development operation was performed.
[0139]
Good S / N at the time of printing (the non-image area is free of background stain, that is, the non-image area of the image forming layer is removed on the printing machine, and the density of the image area is within an appropriate range) As a result of evaluating the number of printed sheets until a printed matter having a print quality was obtained, all of the printing plate materials 1 to 5 exhibited good printability within 20 sheets.
[0140]
(Visibility evaluation during plate inspection)
The exposed printing plate materials 1 to 5 are placed on a member as shown in Table 5 with the image-forming layer side up, and visually and magnified with the following evaluation criteria while illuminating with white light from above. The results are shown in Table 5.
[0141]
Visibility in visual observation
A: Very good
○: Good
Δ: Somewhat bad
×: Defect
Visibility in loupe observation
◎: Line and space images are clearly visible
○: A halftone dot of 2 to 98% can be confirmed.
Δ: Although it is unclear, a halftone dot can be confirmed.
X: It is difficult to confirm halftone dots.
[0142]
[Table 5]

[0143]
From Table 5, a printing plate material of the type that forms an image by removing at least part of the layer formed on the surface of the printing plate material after being attached to the plate cylinder of the printing press having the transmission density of the present invention On the other hand, it can be seen that the plate inspection method of the present invention is very effective.
[0144]
【The invention's effect】
According to the present invention, it is possible to provide a plate inspection method that enables clearer and more stable plate inspection after performing image formation by exposing a printing plate material having a specific transmission density.

Claims (6)

At least the porous hydrophilic layer and the melting point and a layer containing the heat fusible material is 300 ° C. or less 40 ° C. or higher, the transmission density of 0.05 or more and 0.5 or less of the printing plate material onto a substrate After the exposure, the printing plate material is placed on a colored member, and is irradiated with light from above the printing plate material. Light scattering of the printing plate material is suppressed and light transmittance is improved and light is improved. A plate inspection method for a printing plate material, wherein plate inspection is performed while enhancing contrast with an unexposed portion having high scattering properties .   2. The plate inspection method for a printing plate material according to claim 1, wherein the colored member has a reflection density of 0.5 or more and 3.0 or less. A printing plate material having at least a porous hydrophilic layer on a substrate and a layer containing a heat-meltable material having a melting point of 40 ° C. or higher and 300 ° C. or lower and having a transmission density of 0.05 or higher and 0.5 or lower. after exposure and the printing plate material is placed superimposed on a member having a reflective, illuminated from above of the printing plate material, the plate exposing unit light scattering has improved the suppressed light transmission of the material A plate inspection method for a printing plate material, wherein the plate inspection is performed with emphasis on the contrast between the light-scattering property and the unexposed portion having a high light scattering property .   4. The plate inspection method for a printing plate material according to claim 3, wherein the reflectance of the reflective member is 50% or more.   2. A printing plate material of a type that forms an image by removing at least a part of a layer formed on a surface of the printing plate material after being attached to a printing drum of a printing press. The plate inspection method of the printing plate material of any one of -4.   6. The printing plate material according to claim 5, wherein the operation of removing at least a part of the layer formed on the surface is performed by applying at least one of dampening water and ink to the surface of the printing plate material. Plate inspection method.