JPH038537B2 - - Google Patents
Info
- Publication number
- JPH038537B2 JPH038537B2 JP56070799A JP7079981A JPH038537B2 JP H038537 B2 JPH038537 B2 JP H038537B2 JP 56070799 A JP56070799 A JP 56070799A JP 7079981 A JP7079981 A JP 7079981A JP H038537 B2 JPH038537 B2 JP H038537B2
- Authority
- JP
- Japan
- Prior art keywords
- dispersion
- smoothness
- seconds
- photosensitive layer
- resin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000006185 dispersion Substances 0.000 claims description 60
- 239000011347 resin Substances 0.000 claims description 47
- 229920005989 resin Polymers 0.000 claims description 47
- 239000002253 acid Substances 0.000 claims description 35
- 238000007639 printing Methods 0.000 claims description 33
- 239000000463 material Substances 0.000 claims description 27
- 239000011230 binding agent Substances 0.000 claims description 23
- 239000007788 liquid Substances 0.000 claims description 22
- 239000000126 substance Substances 0.000 claims description 9
- 239000002904 solvent Substances 0.000 claims description 5
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 18
- 239000011248 coating agent Substances 0.000 description 13
- 238000000576 coating method Methods 0.000 description 13
- 230000035945 sensitivity Effects 0.000 description 10
- 239000011787 zinc oxide Substances 0.000 description 9
- 238000010998 test method Methods 0.000 description 8
- 239000002245 particle Substances 0.000 description 7
- 230000007423 decrease Effects 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000004925 Acrylic resin Substances 0.000 description 4
- 229920000178 Acrylic resin Polymers 0.000 description 4
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 239000008096 xylene Substances 0.000 description 4
- 239000005995 Aluminium silicate Substances 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 235000012211 aluminium silicate Nutrition 0.000 description 3
- 239000004927 clay Substances 0.000 description 3
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 3
- 239000003960 organic solvent Substances 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000000586 desensitisation Methods 0.000 description 2
- 239000004816 latex Substances 0.000 description 2
- 229920000126 latex Polymers 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 229920001909 styrene-acrylic polymer Polymers 0.000 description 2
- 229920005792 styrene-acrylic resin Polymers 0.000 description 2
- 238000001132 ultrasonic dispersion Methods 0.000 description 2
- WUPHOULIZUERAE-UHFFFAOYSA-N 3-(oxolan-2-yl)propanoic acid Chemical compound OC(=O)CCC1CCCO1 WUPHOULIZUERAE-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 239000002841 Lewis acid Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 239000005083 Zinc sulfide Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 229920000180 alkyd Polymers 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052980 cadmium sulfide Inorganic materials 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 150000007517 lewis acids Chemical class 0.000 description 1
- 238000001459 lithography Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000007645 offset printing Methods 0.000 description 1
- 239000011236 particulate material Substances 0.000 description 1
- 229920006267 polyester film Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 230000001235 sensitizing effect Effects 0.000 description 1
- 229920002050 silicone resin Polymers 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 229910052984 zinc sulfide Inorganic materials 0.000 description 1
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
- G03G5/10—Bases for charge-receiving or other layers
- G03G5/101—Paper bases
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
- G03G5/02—Charge-receiving layers
- G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
- G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
- G03G5/0528—Macromolecular bonding materials
- G03G5/0592—Macromolecular compounds characterised by their structure or by their chemical properties, e.g. block polymers, reticulated polymers, molecular weight, acidity
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
- G03G5/14—Inert intermediate or cover layers for charge-receiving layers
- G03G5/142—Inert intermediate layers
- G03G5/144—Inert intermediate layers comprising inorganic material
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Photoreceptors In Electrophotography (AREA)
- Printing Plates And Materials Therefor (AREA)
Description
本発明は、粒状性光導電性物質を含む電子写真
感光層形成用分散液に関し、特に電子写真平版印
刷材料を製造するのに適した感光層形成用分散液
およびその製造方法に関する。
電子写真感光材料は、導電性支持体の表面に酸
化亜鉛などの粒状性光導電性物質、結着剤樹脂お
よび有機溶媒を少なくとも含む感光層形成用分散
液を塗布し、乾燥して製造されている。
感光層上に画像を形成せしめてオフセツト印刷
の版として使用することは、その製版操作が簡
便、迅速であり、また安価であることから軽印刷
の分野に於て広く普及している。
電子写真平版印刷材料は、感度、調子、濃度、
カブリなどの一般の電子写真複写材料としての諸
特性の他に平版印刷材料としての性質、例えば耐
水性（印刷中の湿し水などによる伸びの防止）、
接着性（印刷中の感光層の膜剥れ）、インキのり
性、耐刷力などが優れていることが要求される。
本発明の目的は、上記したような電子写真特性
の改良された電子写真感光材料、特にその感光層
形成用分散液を提供することにある。
本発明の別の目的は、上記したような電子写真
特性の改良に加えて印刷特性の改良された電子写
真平版印刷材料、特にその感光層形成用分散液を
提供することにある。
一般に酸化亜鉛のような粒状性光導電性物質−
結着剤樹脂分散系層の被塗布物への接着は、粒状
性物質と、結着剤樹脂との混合比に大きく左右さ
れ、樹脂比の高い方がより強固な接着を示すこと
が知られている。優れた接着力は平版印刷中の湿
し水等の影響にも拘らず感光層の剥離を防止する
ことができるから望ましいことである。しかし、
光導電性を示す酸化亜鉛のような粒子が相互に接
触点を持つことなく、高絶縁性樹脂中に完全に離
れ離れとなつて分散した状態では十分な電子写真
特性を発揮できないために樹脂比を極端に高くす
ることは困難である。従つて、通常は光導電性粒
子100重量部に対して樹脂10〜40重量部の範囲く
らいで使用される。
一般に光導電性粒子に対する樹脂比を小さくす
る程高感度が得られ望ましいけれども、やはり感
光層の接着性を悪化することになる。さらに光導
電性粒子に対する樹脂比を小さくするに従つて、
高湿度条件下での濃度の低下あるいはインキのり
性の低下を招く欠点を有している。
本発明者等は、前述した如き諸特性の全部ある
いは殆んどは、或る性質の結合剤樹脂を用い、か
つ特別の性質を示す感光層形成用分散液によつて
極めて満足されるものであることを見出した。
電子写真感光材料は、広い範囲の温度および湿
度条件下でも良好な写真特性を示すものでなけれ
ばならない。特に30℃以上および相対湿度80％以
上のように高温、高湿下では既述したように一般
的に濃度が著しく低下する。それを改善する１つ
の方法として酸価の大きい結着剤樹脂を用いるこ
とは望ましい。しかし、例えば酸価が35〜40以上
の結着剤樹脂を酸化亜鉛のような粒状性光導電性
物質と組合わすと、その分散液粘度が高くなり過
ぎて実用上の問題が生じるだけでなく、増感剤と
しての染料を失効し易くなるという欠点を有す
る。
一方、酸価の小さい、例えば15以下の結着剤樹
脂は、高湿条件下に於る欠点を余り改善しえない
けれども、高分子量の樹脂が得られ易く従つて成
膜性と感光層の接着性とが良好な感光層形成用分
散液を得ることは可能となる。このようなことか
ら酸価の異なる２種以上の結着剤樹脂を組合わせ
て平均酸価３〜35程度とすることにより感光層の
接着性および高温高湿特性の良好な感光層形成用
分散液を得ることが可能となる。しかし、それぞ
れの特性が良好であるといつても、粒状性光導電
性物質に対して限られた量の結着剤樹脂では、そ
れぞれの特性を十分に発揮させることは困難であ
る。
酸価の異なる樹脂、換言すれば粒状性光導性物
質に対する親和力（吸着力）の異なる樹脂、例え
ば酸価15未満の樹脂の少なくとも１つと酸価15以
上の樹脂の少なくとも１つの組合わせからなり、
平均酸価３〜35、好ましくは５〜30である感光層
形成用分散液は下記試験法に合格するような性質
を付与したとき、それぞれの樹脂の特長が最大限
に発揮され、電子写真特性および印刷特性が飛躍
的に改良された電子写真感光材料ならびに電子写
真平版印刷材料を提供しうることを見出した。
本発明の電子写真感光層形成用分散液は、少な
くとも粒状性光導電性物質、酸価の異なる２種以
上の結着剤樹脂（平均酸価５〜30）および溶媒を
含む分散液であつて、該分散液はベツク平滑度が
実質的に無限大値の平滑な物体表面に被覆したと
き、その表面のベツク平滑度が約1000秒乃至4000
秒の範囲の値を示すものであることによつて特徴
づけられる。
上記試験法は、フイルムあるいは金属板（例え
ばアルミニウム板）の如き表面が極めて平滑な物
体、即ちベツク平滑度（JIS−P8119による）が
数万秒あるいは数十万秒のように実質的に無限大
値を示す物体表面に、通常の方法で塗布し、その
塗布物表面のベツク平滑度（JIS−P8119による）
を測定することによつて容易に実施することがで
きる。本発明の感光層形成用分散液は、酸化亜鉛
などの粒状性光導電性物質、酸価の異なる２種以
上の結着剤樹脂および有機溶媒さらには増感色素
あるいはルイス酸の如き増感剤などを混合し、ボ
ールミル、ロールミル、サンドミル、ホモミキサ
ー、ホモジナイザー、超音波振動機などで撹拌、
分散する従来の調製法と同様にして調製すること
ができる。
本発明の感光層形成用分散液の特別の性質は従
来法による分散の程度に比べて相当に分散度を強
くすることによつて、しかし過度の分散度合にな
らないように留意することによつて付与される。
その分散の度合は、前記したベツク平滑度の測定
による試験法によつて明確に規定することができ
ることが判明した。
前記の試験法において、ベツク平滑度が約4000
秒を越えると、減感、軟調化、濃度低下などの欠
点が生じ、約1000秒以下、通常約600秒以下の従
来法によるときは、低い濃度特に高温高湿度条件
下での濃度低下、インキ乗り不良、感光層の接着
不良などの欠点が生じる。
電子写真感光材料、殊に電子写真平版印刷材料
には通常は紙支持体が広く用いられ、感光層の平
滑性および耐水性、耐溶剤性を良くするために紙
基体と感光層との間に所謂プレコート層が設けら
れ、該プレコート層は、更にスーパーカレンダー
処理などが施こされることはよく知られている。
しかし、このようなプレコート層の平滑性を極
めて高いものにする従来法においては、従来法に
より調製した感光層形成用分散液を塗布しただけ
では、その塗布物表面の平滑性には自ずと限界が
ある。実際に市販されている各種の電子写真平版
印刷材料（プレコート層を持つ紙支持体）でも、
精々300秒前後までのベツク平滑度しか有してい
ない。
本発明は、プレコート層の平滑性アツプに基づ
く感光層の平滑性アツプよりもより平滑にするこ
とができ、かつ電子写真特性および印刷特性に卓
越した利点を与えることができる。
本発明の感光層形成用分散液は、粒状性光導電
性物質に対する結着剤樹脂の重量比を可能な限り
小さくすることができるため高感度であり、それ
にも拘らず高温、高湿度条件下での濃度低下もな
く、低湿度条件下でのカブリもなく、かつ感光層
の接着性、インキ乗り性および耐刷力が著しく改
良された電子写真感光材料ならびに電子写真平版
印刷材料を製造することができる。
前述の試験法に合格する本発明の感光層形成用
分散液は、塗布する支持体の違いによつて自ずと
そのベツク平滑度は異なる。一具体例によれば、
前述の試験法で約1000秒乃至約4000秒の平滑度を
与える分散液は、紙支持体表面のポリマーから成
るプレコート層上に塗布した場合、通常約500秒
乃至約1500秒のベツク平滑度を与える。従つて、
約500秒以下または約1500秒以上では既述した如
き欠点を生じることになる。
本発明によれば、紙基体上にプレコート層を介
して光導電層を有し、光導電層表面のベツク平滑
度が約600秒乃至約1400秒である改良された電子
写真平版印刷材料が提供される。
本発明は、前記したような分散方法によつて従
来法の分散程度よりも相当に分散時間を長くする
とか分散強度を強めるとかにより、しかしそれも
余り過度に行なわないある特定の範囲の分散程度
とすることによつて可能になるという予想外の事
実の発見に基づく。この特定の範囲の分散度を有
する感光層形成用分散液が相矛盾することの多い
電子写真特性および印刷特性の全て或いは殆んど
を極めて良好ならしめることは、従来の分散技術
の知見からは予期しえないことであつた。
前記試験法に合格する分散液を得るには、分散
法によつても異なるが、既述した紙支持体の平版
印刷材料で精々300秒までのベツク平滑度を得る
ために行なつていた分散度を数倍（時間あるいは
強度として）、一般には３〜６倍程度強化するこ
とによつて可能とすることができる。
本発明の感光層形成用分散液は、酸化亜鉛、硫
化亜鉛、硫化カドミウム顔料などの光導電性粒子
100重量部に対して酸価の異なる２種以上の結着
剤樹脂10〜40重量部、好ましくは10〜30重量部の
割合で含むことが好ましい。
結着剤樹脂は、アクリル樹脂、シリコン樹脂、
アルキツド樹脂など従来から知られているものを
２種以上組合わせて用いることができる。
用いられる結着剤樹脂の酸価（A.V）は、０〜
40もしくはそれ以上のものであることができる。
平均酸価が５〜30、好ましくは10〜25の範囲にな
るように２種以上の結着剤樹脂が組合わされる。
組合わされる結着剤樹脂の酸価の差は、少なく
とも５、好ましくは10以上であるような樹脂の組
合わせを少なくとも１つ有していることが好まし
い。
具体的な例として酸価10以下の樹脂１種と酸価
15以上の樹脂１種および必要により任意の酸価を
有する樹脂からなる組合わせを挙げることができ
る。
本明細書において平均酸価とは、２種以上の結
着剤樹脂の個々の酸価値（a1、a2、a3…）に全樹
脂量に占める各々の樹脂の重量％（w1、w2、w3
…）を積算し、それらの値を和算して求めること
ができる。この平均酸価は、樹脂固有の酸価を測
定する方法と同様にして測定することができ、そ
れは上記計算値とほぼ一致する。一例を挙げれば
酸価10の樹脂と酸価20の樹脂とを重量比で等しく
組合わせたとき、その平均酸価は15となる。
粒状性光導性物質に対する親和力の異なる２種
以上の結着剤樹脂を用いるとき、好ましくは酸価
の小さい樹脂として平均分子量10万以上の如き成
膜性および接着性が良好な樹脂を用いるとき、そ
の平均酸価と等しい酸価を有する樹脂を単独で用
いたときに比べて、前記試験法に合格するように
同じ条件の分散が施こされると、より良好な平滑
性を与えることができ、従つてより良好な電子写
真特性および印刷特性を付与することができるも
のである。
分散液の溶媒としては、トルエン、キシレンな
ど従来知られているものが任意に用いられる。
本発明の感光層形成用分散液は、紙基体上に設
けられたプレコート層上に塗布することによつて
電子写真平版印刷材料とすることができ、そのプ
レコート層は特公昭40−18708、同昭45−10272、
同昭47−23594、同昭47−37451、特開昭48−9803
などに記載のような耐水性あるいは耐有機溶剤性
の任意のポリマー層であることができ、感光層の
平滑性を上げるためにカオリンクレーなどの顔料
などを含むこともできる。
実施例 １
下記処方の感光層形成用塗布液を準備する。
酸化亜鉛 200重量部
結着剤樹脂 40 〃
ローズベンガル（１％液） 15 〃
キシレン 250 〃
結着剤樹脂は、市販されているものを用い、酸
価（A.V）の異なるものを下記表のように配合し
た。樹脂ａはアクリル系のA.V＝11.9、樹脂ｂは
アクリル系のA.V＝7.6、樹脂ｃはスチレン−ア
クリル系のA.V＝18.3、樹脂ｄはスチレン−アク
リル系のA.V＝27.7のものである。（ ）内は重
量比（％）を示す。
The present invention relates to a dispersion for forming an electrophotographic photosensitive layer containing a particulate photoconductive substance, and particularly to a dispersion for forming a photosensitive layer suitable for producing an electrophotographic lithographic printing material and a method for producing the same. Electrophotographic light-sensitive materials are produced by coating the surface of a conductive support with a photosensitive layer-forming dispersion containing at least a particulate photoconductive substance such as zinc oxide, a binder resin, and an organic solvent, and drying the dispersion. There is. Forming an image on a photosensitive layer and using it as a plate for offset printing is widely used in the field of light printing because the plate-making operation is simple, quick, and inexpensive. Electrophotographic lithographic printing materials are characterized by sensitivity, tone, density,
In addition to various properties as a general electrophotographic copying material such as fog, properties as a lithographic printing material, such as water resistance (prevention of stretching due to dampening water etc. during printing),
It is required to have excellent adhesion (peeling of the photosensitive layer during printing), ink adhesion, printing durability, etc. An object of the present invention is to provide an electrophotographic light-sensitive material with improved electrophotographic properties as described above, particularly a dispersion thereof for forming a light-sensitive layer. Another object of the present invention is to provide an electrophotographic lithographic printing material, particularly a dispersion for forming a photosensitive layer thereof, which has improved printing properties in addition to the above-mentioned improvements in electrophotographic properties. Generally particulate photoconductive materials such as zinc oxide
It is known that the adhesion of the binder resin dispersion layer to the coated object is largely influenced by the mixing ratio of the particulate material and the binder resin, and it is known that the higher the resin ratio, the stronger the adhesion. ing. Excellent adhesion is desirable because it can prevent the photosensitive layer from peeling off despite the influence of dampening water and the like during lithographic printing. but,
Particles such as zinc oxide, which exhibit photoconductivity, cannot exhibit sufficient electrophotographic properties when they are completely separated and dispersed in a highly insulating resin without having contact points with each other. It is difficult to make it extremely high. Therefore, the resin is usually used in an amount of about 10 to 40 parts by weight per 100 parts by weight of the photoconductive particles. Although it is generally desirable to obtain higher sensitivity as the ratio of resin to photoconductive particles is reduced, the adhesion of the photosensitive layer is also deteriorated. Furthermore, as the ratio of resin to photoconductive particles is reduced,
It has the disadvantage of causing a decrease in density or ink adhesion under high humidity conditions. The present inventors believe that all or most of the above-mentioned properties can be extremely satisfied by a dispersion for forming a photosensitive layer that uses a binder resin of certain properties and exhibits special properties. I discovered something. Electrophotographic materials must exhibit good photographic properties over a wide range of temperature and humidity conditions. In particular, at high temperatures and high humidity such as 30° C. or higher and relative humidity of 80% or higher, the concentration generally decreases significantly as described above. As one method to improve this, it is desirable to use a binder resin with a high acid value. However, when a binder resin with an acid value of 35-40 or higher is combined with a particulate photoconductive material such as zinc oxide, the viscosity of the dispersion becomes too high, which not only causes practical problems. However, it has the disadvantage that the dye as a sensitizer tends to expire. On the other hand, binder resins with a low acid value, for example, 15 or less, cannot improve the disadvantages under high humidity conditions much, but it is easy to obtain a high molecular weight resin and therefore improves film formability and the photosensitive layer. It becomes possible to obtain a dispersion for forming a photosensitive layer with good adhesiveness. For this reason, by combining two or more types of binder resins with different acid values to give an average acid value of about 3 to 35, a dispersion for forming a photosensitive layer with good adhesion and high temperature and high humidity characteristics can be obtained. It becomes possible to obtain liquid. However, even if each of the properties is good, it is difficult to fully exhibit each of the properties using a limited amount of binder resin for the particulate photoconductive material. Consists of a combination of resins with different acid values, in other words, resins with different affinities (adsorption powers) for particulate photoconductive substances, for example, at least one resin with an acid value of less than 15 and at least one resin with an acid value of 15 or more,
When a dispersion for forming a photosensitive layer with an average acid value of 3 to 35, preferably 5 to 30 is imparted with properties that pass the following test method, the features of each resin are maximized and the electrophotographic properties are improved. The present invention has also found that it is possible to provide an electrophotographic light-sensitive material and an electrophotographic lithographic printing material with dramatically improved printing properties. The dispersion liquid for forming an electrophotographic photosensitive layer of the present invention is a dispersion liquid containing at least a particulate photoconductive substance, two or more binder resins having different acid values (average acid value 5 to 30), and a solvent. When the dispersion is coated on a smooth object surface with a substantially infinite Bekk smoothness, the Bekk smoothness of the surface is approximately 1000 seconds to 4000 seconds.
It is characterized by indicating a value in the range of seconds. The above test method is applicable to objects with extremely smooth surfaces such as films or metal plates (e.g. aluminum plates), which have a Beck's smoothness (according to JIS-P8119) of tens of thousands or hundreds of thousands of seconds, which is virtually infinite. Apply the coating in the usual way to the surface of the object that shows the value, and check the base smoothness of the surface of the applied object (according to JIS-P8119).
This can be easily carried out by measuring. The dispersion for forming a photosensitive layer of the present invention comprises a particulate photoconductive substance such as zinc oxide, two or more binder resins with different acid values, an organic solvent, and a sensitizer such as a sensitizing dye or a Lewis acid. etc., and stir with a ball mill, roll mill, sand mill, homomixer, homogenizer, ultrasonic vibrator, etc.
It can be prepared in the same manner as the conventional preparation method of dispersion. The special properties of the dispersion liquid for forming a photosensitive layer of the present invention are achieved by making the degree of dispersion considerably stronger compared to the degree of dispersion obtained by conventional methods, but by being careful not to make the degree of dispersion excessive. Granted.
It has been found that the degree of dispersion can be clearly defined by the above-mentioned test method based on the measurement of Beck smoothness. In the above test method, the Beck smoothness was approximately 4000.
If the time exceeds 100 seconds, disadvantages such as desensitization, softening, and decrease in density will occur.If the conventional method is used for less than about 1000 seconds, usually about 600 seconds or less, it will cause disadvantages such as desensitization, softening, and decrease in density. There are drawbacks such as poor riding and poor adhesion of the photosensitive layer. Paper supports are commonly used in electrophotographic materials, especially electrophotographic lithographic materials, and in order to improve the smoothness, water resistance, and solvent resistance of the photosensitive layer, there is a layer between the paper substrate and the photosensitive layer. It is well known that a so-called precoat layer is provided, and the precoat layer is further subjected to a supercalender treatment or the like. However, in the conventional method of achieving extremely high smoothness of such a precoat layer, there is a limit to the smoothness of the surface of the coated material simply by applying a dispersion for forming a photosensitive layer prepared by the conventional method. be. Even with various electrophotographic lithographic printing materials (paper supports with precoat layers) that are actually commercially available,
It only has a Beck smoothness of around 300 seconds at most. The present invention can make the photosensitive layer smoother than the smoothness of the photosensitive layer based on the increased smoothness of the precoat layer, and can provide outstanding advantages in electrophotographic properties and printing properties. The dispersion liquid for forming a photosensitive layer of the present invention has high sensitivity because the weight ratio of the binder resin to the particulate photoconductive substance can be made as small as possible. To produce an electrophotographic light-sensitive material and an electrophotographic lithographic printing material, which have no decrease in density under low humidity conditions, no fogging under low humidity conditions, and have significantly improved adhesion of a photosensitive layer, ink transferability, and printing durability. Can be done. The dispersion liquid for forming a photosensitive layer of the present invention that passes the above-mentioned test method naturally has different base smoothness depending on the support to which it is applied. According to one specific example,
A dispersion that gives a smoothness of about 1000 seconds to about 4000 seconds according to the test method described above will usually give a Bec. give. Therefore,
If the time is less than about 500 seconds or more than about 1500 seconds, the above-mentioned drawbacks will occur. According to the present invention, there is provided an improved electrophotographic lithographic printing material which has a photoconductive layer on a paper substrate via a precoat layer and has a surface smoothness of about 600 seconds to about 1400 seconds. be done. The present invention uses the above-described dispersion method to significantly lengthen the dispersion time or strengthen the dispersion intensity compared to the dispersion level of the conventional method, but it is possible to achieve a dispersion level within a certain range that is not too excessive. It is based on the discovery of an unexpected fact that is made possible by From the knowledge of conventional dispersion technology, it is clear that a dispersion for forming a photosensitive layer having a dispersion degree in this specific range has extremely good all or most of the electrophotographic properties and printing properties, which are often contradictory. It was something unexpected. In order to obtain a dispersion that passes the above test method, although it varies depending on the dispersion method, the dispersion that was carried out in order to obtain a Betzk smoothness of up to 300 seconds at most with the lithographic printing material of the paper support mentioned above is necessary. This can be achieved by increasing the strength several times (in terms of time or intensity), generally by about 3 to 6 times. The photosensitive layer forming dispersion of the present invention comprises photoconductive particles such as zinc oxide, zinc sulfide, and cadmium sulfide pigments.
It is preferable that two or more binder resins having different acid values are contained in a ratio of 10 to 40 parts by weight, preferably 10 to 30 parts by weight, per 100 parts by weight. Binder resins include acrylic resin, silicone resin,
Two or more conventionally known alkyd resins can be used in combination. The acid value (AV) of the binder resin used is 0 to
It can be 40 or more.
Two or more binder resins are combined so that the average acid value is in the range of 5 to 30, preferably 10 to 25. It is preferable to have at least one resin combination in which the difference in acid value between the binder resins to be combined is at least 5, preferably 10 or more. A specific example is one type of resin with an acid value of 10 or less and an acid value
Examples include a combination of one type of resin of 15 or more and, if necessary, a resin having an arbitrary acid value. In this specification, the average acid value refers to the individual acid values (a 1 , a 2 , a 3 . . . ) of two or more binder resins, as well as the weight percent (w 1 , w2 , w3
...) and then add those values together. This average acid value can be measured in the same manner as the method for measuring the resin-specific acid value, and it almost agrees with the above calculated value. For example, when a resin with an acid value of 10 and a resin with an acid value of 20 are combined in equal weight ratio, the average acid value is 15. When using two or more binder resins with different affinities for particulate photoconductive substances, preferably when using a resin with a low acid value and good film forming properties and adhesive properties such as an average molecular weight of 100,000 or more, Compared to when a resin having an acid value equal to the average acid value is used alone, if dispersion is performed under the same conditions to pass the above test method, better smoothness can be provided. Therefore, it is possible to impart better electrophotographic properties and printing properties. As the solvent for the dispersion, any conventionally known solvent such as toluene and xylene can be used. The dispersion liquid for forming a photosensitive layer of the present invention can be made into an electrophotographic lithographic printing material by coating it on a precoat layer provided on a paper substrate, and the precoat layer is coated in Japanese Patent Publication No. 40-18708, Showa 45-10272,
1972-23594, 1977-37451, JP 48-9803
The photosensitive layer may be any water-resistant or organic solvent-resistant polymer layer as described in , et al., and may also contain a pigment such as kaolin clay in order to improve the smoothness of the photosensitive layer. Example 1 A coating solution for forming a photosensitive layer having the following formulation is prepared. Zinc oxide 200 parts by weight Binder resin 40 〃 Rose Bengal (1% liquid) 15 〃 Xylene 250 〃 Use commercially available binder resins, with different acid values (AV) as shown in the table below. It was blended into. Resin a is an acrylic type with an AV of 11.9, resin b is an acrylic type with an AV of 7.6, resin c is a styrene-acrylic type with an AV of 18.3, and resin d is a styrene-acrylic type with an AV of 27.7. Figures in parentheses indicate weight ratio (%).
【表】
これらをボールミルを用いて１昼夜（16時間）、
２昼夜（40時間）、３昼夜（64時間）および４昼
夜（88時間）分散し、厚み100μのポリエステル
フイルム上に20ｇ／m2（固形）となるように塗布
乾燥する。順次分散液イ，ロ，ハおよびニとし、
それぞれのベツク平滑度を測定した結果を下記表
にしている。[Table] Using a ball mill, process these for one day and night (16 hours).
The mixture was dispersed for 2 days and nights (40 hours), 3 days and nights (64 hours), and 4 days and nights (88 hours), coated and dried on a polyester film with a thickness of 100 μm to a weight of 20 g/m 2 (solid). Sequentially dispersion liquids A, B, C and D,
The results of measuring each Beck's smoothness are shown in the table below.
【表】
これらの分散液を用いて次のようにして平版印
刷材料を作製した。
Ｎ材パルプを主体とした紙基体の表側に下記組
成のプレコート層形成用塗布液を乾燥塗布量が９
ｇ／m2となるように塗布、乾燥し、そのプレコー
ト層表面をスーパーカレンダーにかける。
〈プレコート層形成用塗布液〉
カオリンクレー（50％水分散液） 200重量部
微粒状ポリスチレン（平均粒径0.5μ、48.5％
水分散液） 150 〃
ポリビニルアルコール（10％水溶液）
150 〃
SBRラテツクス（固形分50％） 150 〃
次いで、紙基体の裏側に下記組成の導電層形成
用塗布液を乾燥塗布量が13ｇ／m2となるように塗
布、乾燥する。
〈導電層形成用塗布液〉
カオリンクレー（50％水分散液） 600重量部
ポリビニルアルコール（10％水溶液）
200 〃
SBRラテツクス（固形分50％） 450 〃
ポリビニルベンジルトリメチルアンモニウム
クロライド（固形分30％） 200 〃
前記の分散液12種をプレコート層上に同様に塗
布、乾燥して平版印刷プレートとした。プレート
は、塗布液１〜３と分散液イ〜ニとの組合わせに
より、１−イ〜１−ニ、２−イ〜２−ニ、３−イ
〜３−ニと称する。
それらプレートの感光層表面のベツク平滑度を
下記第１表に示している。[Table] Using these dispersions, lithographic printing materials were produced in the following manner. A coating solution for forming a precoat layer with the following composition was applied on the front side of a paper base mainly made of N material pulp to a dry coating amount of 9.
g/m 2 , dried, and the surface of the precoat layer was supercalendered. <Coating liquid for pre-coat layer formation> Kaolin clay (50% aqueous dispersion) 200 parts by weight Finely divided polystyrene (average particle size 0.5μ, 48.5%
aqueous dispersion) 150 〃 Polyvinyl alcohol (10% aqueous solution)
150 〃 SBR latex (solid content 50%) 150 〃 Next, a coating liquid for forming a conductive layer having the following composition is applied to the back side of the paper base so that the dry coating amount is 13 g/m 2 and dried. <Coating liquid for forming conductive layer> Kaolin clay (50% aqueous dispersion) 600 parts by weight Polyvinyl alcohol (10% aqueous solution)
200 〃 SBR latex (solid content 50%) 450 〃 Polyvinylbenzyltrimethylammonium chloride (solid content 30%) 200 〃 The above 12 kinds of dispersions were similarly applied onto the precoat layer and dried to prepare a lithographic printing plate. The plates are referred to as 1-i to 1-ni, 2-i to 2-ni, and 3-i to 3-ni depending on the combination of coating liquids 1 to 3 and dispersion liquids a to ni. The Beck smoothness of the surface of the photosensitive layer of these plates is shown in Table 1 below.
【表】
これらのプレートを30℃、相対湿度85％の条件
下で電子写真製版機ダイヤフアツクスEP−11（三
菱製紙(株)製、液体現像用製版機）で製版し、電子
写真平版マスター用エツチ液ダイヤフアツクス
LOM−OH（三菱製紙(株)製）で不感脂化処理を施
し、印刷機トーコーMode1810（東京航空計器(株)
製）で印刷した。
各プレートの感光層上に於る最大濃度および相
対感度を第２表に示している。表中、上段は濃
度、下段は相対感度を表わす。相対感度は３−イ
のプレートを100とした。[Table] These plates were made using an electrophotographic plate making machine Diafax EP-11 (manufactured by Mitsubishi Paper Industries, Ltd., liquid development plate making machine) under conditions of 30°C and 85% relative humidity, and an electrophotographic lithography master was used. etchant diaphragm
Desensitized with LOM-OH (manufactured by Mitsubishi Paper Mills Co., Ltd.), and printing machine Toko Mode 1810 (manufactured by Tokyo Aircraft Instruments Co., Ltd.).
Printed by Manufacturer). The maximum density and relative sensitivity on the photosensitive layer of each plate are shown in Table 2. In the table, the upper row represents the concentration, and the lower row represents the relative sensitivity. The relative sensitivity was set at 100 for the 3-I plate.
【表】
第２表の結果は、本発明の感光層形成用分散液
を用いたプレート（２−ロ）、（２−ハ）、（３−
ロ）、および（３−ハ）は、高温高湿条件下にお
いても十分に高い濃度を有しており、酸価がほぼ
等しいプレート（１−ロ）および（１−ハ）より
も優れていることが判る。また、感度の低下も改
良され、高感度であることを示している。
これらのプレートを用いて印刷した結果、いず
れもイの分散液を用いたプレートよりインキ乗り
が良好であり、かつ１の塗布液よりも２および３
の塗布液の方がインキ乗りが良好でありさらに
7000枚以上の印刷での感光層の膜剥れ及び耐刷性
においても本発明の優秀性が明らかであつた。
尚、１−イ、２−イおよび３−イの各プレートに
おける平滑性は、各社メーカーの市販している平
版印刷プレートと同程度のものであつた。
実施例 ２
下記の感光層形成用分散液を用いる以外は、実
施例１を繰返した。但し、分散は超音波分散機を
用いて激しく分散しながら平滑度の異なるものを
調製した。
酸化亜鉛 200重量部
アクリル系樹脂（A.V＝6.2） 20 〃
アクリル系樹脂（A.V＝17.4） 10 〃
スチレンアクリル系樹脂（A.V＝25）
10 〃
ローズベンガル（１％液） 15 〃
キシレン 250 〃
以後、実施例１と同様に試験したところ同様な
結果が得られた。プレートの平滑度、30、80％
RHでの濃度および相対感度を第３表にまとめて
いる。[Table] The results in Table 2 are plates (2-B), (2-C), (3-3) using the photosensitive layer forming dispersion of the present invention.
b) and (3-c) have sufficiently high concentrations even under high temperature and high humidity conditions, and are superior to plates (1-b) and (1-c), which have approximately the same acid value. I understand that. Furthermore, the decrease in sensitivity was also improved, indicating high sensitivity. As a result of printing using these plates, the ink coverage was better than that of the plate using dispersion A, and coating liquids 2 and 3 were better than those using dispersion 1.
The coating liquid has better ink coverage, and
The superiority of the present invention was also evident in terms of peeling of the photosensitive layer and printing durability after printing 7000 sheets or more.
The smoothness of each of the plates 1-A, 2-I, and 3-I was comparable to that of commercially available lithographic printing plates from each manufacturer. Example 2 Example 1 was repeated except that the following dispersion for forming a photosensitive layer was used. However, the dispersion was performed using an ultrasonic dispersion machine, and while vigorously dispersing the particles, samples with different degrees of smoothness were prepared. Zinc oxide 200 parts by weight Acrylic resin (AV=6.2) 20 Acrylic resin (AV=17.4) 10 Styrene acrylic resin (AV=25)
10 Rose Bengal (1% liquid) 15 Xylene 250 Thereafter, tests were conducted in the same manner as in Example 1, and the same results were obtained. Plate smoothness, 30, 80%
Concentrations and relative sensitivities at RH are summarized in Table 3.
【表】
実施例 ３
下記の感光層形成用分散液を用いて実施例２と
同様に超音波分散機で激しく分散し、同様な平版
印刷材料を作製した。ベツク平滑度は925秒であ
つた。高温高湿下においても高感度で高濃度、か
つインキ乗り良好で感光層の膜剥れもなく高耐刷
力の印刷版であつた。
酸化亜鉛 200重量部
アクリル系樹脂（A.V＝11.9） 40 〃
スチレンアクリル系樹脂（A.V＝40.1）
10 〃
ローズベンガル（１％液） 20 〃
キシレン 250 〃[Table] Example 3 A similar lithographic printing material was prepared by vigorously dispersing the following dispersion liquid for forming a photosensitive layer using an ultrasonic dispersion machine in the same manner as in Example 2. The Beck smoothness was 925 seconds. Even under high temperature and high humidity conditions, the printing plate had high sensitivity, high density, good ink coverage, and no peeling of the photosensitive layer and had high printing durability. Zinc oxide 200 parts by weight Acrylic resin (AV=11.9) 40 Styrene acrylic resin (AV=40.1)
10 〃 Rose Bengal (1% liquid) 20 〃 Xylene 250 〃
Claims (1)
る２種以上の結着剤樹脂（その平均酸価は５〜
30）および溶媒を含む分散液であつて該分散液は
実質的に無限大値のベツク平滑度を有する物体表
面に被覆したとき、その表面のベツク平滑度が約
1000秒乃至約4000秒の値になるように分散度を制
御されたものであることを特徴とする改良された
電子写真感光層形成用分散液。 ２ 導電性支持体上にプレコート層を介して光導
電性層を有する電子写真平版印刷材料であつて、
該光導電性層は少なくとも粒状性光導電性物質お
よび酸価の異なる２種以上の結着剤樹脂（その平
均酸価は５〜30）を含み、実質的に無限大値のベ
ツク平滑度を有する物体表面に被覆したとき、そ
の表面のベツク平滑度が約1000秒乃至約4000秒に
なるように分散度を制御された分散液を塗布する
ことにより設けられたものであり、その表面のベ
ツク平滑度が約500秒乃至約1500秒の範囲である
ことを特徴とする電子写真平版印刷材料。[Scope of Claims] 1. At least a particulate photoconductive substance, two or more binder resins with different acid values (the average acid value is 5 to 5).
30) and a dispersion containing a solvent, when the dispersion is coated on the surface of an object having a substantially infinite Bekk's smoothness, the Bekk's smoothness of the surface is approximately
An improved dispersion liquid for forming an electrophotographic photosensitive layer, characterized in that the degree of dispersion is controlled to have a value of 1000 seconds to about 4000 seconds. 2. An electrophotographic lithographic printing material having a photoconductive layer on a conductive support via a precoat layer,
The photoconductive layer contains at least a particulate photoconductive substance and two or more types of binder resins having different acid values (the average acid value is 5 to 30), and has a substantially infinite Bekk smoothness. It is applied by applying a dispersion liquid whose degree of dispersion is controlled so that when coated on the surface of an object, the surface smoothness is from about 1000 seconds to about 4000 seconds. An electrophotographic lithographic printing material characterized in that its smoothness is in the range of about 500 seconds to about 1500 seconds.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7079981A JPS57186756A (en) | 1981-05-13 | 1981-05-13 | Improved electrophotographic photosensitive material |
| US06/354,799 US4427754A (en) | 1981-03-10 | 1982-03-04 | Electrophotographic lithographic printing plate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7079981A JPS57186756A (en) | 1981-05-13 | 1981-05-13 | Improved electrophotographic photosensitive material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57186756A JPS57186756A (en) | 1982-11-17 |
| JPH038537B2 true JPH038537B2 (en) | 1991-02-06 |
Family
ID=13441946
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7079981A Granted JPS57186756A (en) | 1981-03-10 | 1981-05-13 | Improved electrophotographic photosensitive material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57186756A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59170861A (en) * | 1983-03-16 | 1984-09-27 | Mitsubishi Paper Mills Ltd | Electrophotographic offset master |
| JPH0614198B2 (en) * | 1986-03-18 | 1994-02-23 | 三菱製紙株式会社 | Printing plate for electrophotographic plate making |
| JPS62288080A (en) * | 1986-06-06 | 1987-12-14 | Mitsubishi Paper Mills Ltd | Thermal transfer ink film |
| JPH03141369A (en) * | 1990-09-21 | 1991-06-17 | Mitsubishi Paper Mills Ltd | Electrophotographic offset master |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5031011A (en) * | 1973-07-26 | 1975-03-27 | ||
| JPS5644690A (en) * | 1979-09-20 | 1981-04-23 | Ricoh Co Ltd | Original form for offset printing |
-
1981
- 1981-05-13 JP JP7079981A patent/JPS57186756A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5031011A (en) * | 1973-07-26 | 1975-03-27 | ||
| JPS5644690A (en) * | 1979-09-20 | 1981-04-23 | Ricoh Co Ltd | Original form for offset printing |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57186756A (en) | 1982-11-17 |
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