Photosensitive lithographic printing plate precursors and methods of preparing printing plate therefrom

A photosensitive lithographic printing plate precursor which has a camera speed together with all the advantageous features inherent to positive type, conventional PS plates is disclosed. On an aluminum support having a hydrophilic surface, one provides first a positive type non-silver photosensitive layer capable of forming an oleophilic image, and then superposes thereon an unfogged positive type internally sensitized silver halide photographic emulsion coating.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a photosensitive lithographic printing plate 
precursor making use of the high sensitivity to light of silver halide and 
also to a method of printing master preparation using such precursors. 
More specifically, the present invention relates to a high speed 
photosensitive lithographic printing plate precursor of the positive 
working type and to a method of preparing a printing plate therefrom. 
2. Description of the Prior Art 
There are a variety of well known positive type photosensitive lithographic 
printing plate precursors including silver halide as an emulsion layer as 
described in, for example, U.S. Pat. Nos. 3,083,097, 3,161,508, 3,721,559 
and 3,146,104, etc. However, most of these suffer from various 
disadvantages including a low degree of printing durability, a high 
probability of staining, insufficient oleophilicity in the image areas, 
etc. 
On the other hand, British Pat. No. 1,227,603, U.S. Pat. No. 3,245,793, 
U.S. Defensive Publication T870,022, German Patent Application (OLS) Nos. 
2,517,711 and 2,646,763, U.S. Pat. No. 3,567,445, etc., describe 
photosensitive lithographic printing plate precursors in which the 
non-silver photosensitive layer which typically is used in the 
conventional PS plate is overcoated with a silver halide emulsion layer. 
Moreover, as the first British Patent cited above mentions that 
electrophotographic processes or a silver halide diffusion transfer 
process (hereafter abbreviated DTR process) can also be used to provide a 
masking image which prevents active light from reaching the positive type 
non-silver photosensitive layer. However, electrophotographic processes 
are complicated and the reproduced image lacks stability in comparison to 
that obtained with PS plates. On the other hand, a DTR process suffers 
from its complicated processing steps. 
U.S. Pat. No. 4,168,167 discloses a positive type PS plate utilizing a 
photosensitive coating containing unfogged and internally sensitized 
silver halide grains provided on an aluminum support. The lithographic 
printing plate prepared from this precursor still needs improvement for a 
tendency to smudge in non-image areas, for ink receptivity in image areas, 
tone reproduction capability, etc. 
Furthermore, as the above-cited U.S. Pat. No. 3,567,445 sets forth, one can 
produce a positive type PS plate by superimposing a conventional negative 
type silver halide coating on a conventionally known negative type 
non-silver photosensitive layer. However, in such a combination, one must 
recall that most of the photosensitive materials used in a negative type 
non-silver photosensitive layer (e.g., diazonium compounds) tend to 
adversely affect the photographic properties of the silver halide grains. 
In the case of a photopolymerizable monomer or photo-crosslinkable 
oligomer type PS material, another disadvantage is that an organic solvent 
must be used at development. Accordingly, intricate manufacturing 
operations and relatively high manufacturing costs are inevitable, and the 
cost of printing plate preparation tends to increase. 
SUMMARY OF THE INVENTION 
In view of the present technology, the inventors have found, as a result of 
an extensive study, that a specific combination of a certain type of 
non-silver photosensitive layer and a certain type of silver halide 
emulsion can markedly improve the conventional technology. Thus, the 
present invention provides a photosensitive lithographic printing plate 
precursor comprising an aluminum support having a hydrophilic surface, (a) 
a positive type non-silver photosensitive layer capable of providing an 
oleophilic image or a layer comprising a water-insoluble, oleophilic 
resinous material, and (b) a photographic silver halide emulsion coating, 
these two coatings (a) and (b) being superimposed on the support in that 
order, characterized in that the silver halide emulsion is an unfogged 
internally sensitized emulsion and further the emulsion does not contain 
any tanning developing agent. 
In accordance with the present invention, positive working images having 
good image quality and durability are formed in a PS material using an 
internally sensitized silver halide emulsion layer. The exposed and 
developed emulsion layer forms an image which acts as a resist image or an 
optical mask depending on whether the layer underlying the image is a 
layer of a non-sensitive oleophilic resinous material in accordance with 
one embodiment of the present invention, or a positive-type photosensitive 
layer in accordance with another embodiment of the invention. Where the 
photosensitive lithographic plate of the invention comprises a 
non-sensitive oleophilic resinous material, the silver halide emulsion 
layer is tanning developed to provide a resist image and the unprotected 
regions of the oleophilic resin-containing layer are eliminated with a 
suitable solvent to expose the hydrophilic surface of the aluminum 
support. In the other embodiment of the invention, a positive-type 
photosensitive layer is employed under the silver halide emulsion layer 
and a silver image is formed in the emulsion layer, which acts as an 
optical mask through which the underlying photosensitive layer is exposed. 
The photosensitive layer is developed to uncover the aluminum support in 
the areas not masked by the silver image. 
DETAILED DESCRIPTION OF THE INVENTION 
Generally speaking, the latent image distribution in an individual silver 
halide grain involved in image recording is controlled depending on the 
purpose of the finished product. In the case of high-speed negative film 
for ordinary photographic use, the latent image is located at the surface. 
Such a silver halide grain is designated as a surface sensitized grain. On 
the other hand, internally sensitized grains are also possible which form 
latent images predominantly inside the crystals without giving rise to 
surface latent images. In the past, internally sensitized silver halide 
grains have been said to be made of chemically unsensitized, relatively 
low-speed crystals. The internally sensitized grains used in the present 
invention exhibit sufficiently high photographic speed from practical 
viewpoint and can be specially prepared. For example, one can prepare such 
grains by covering chemically sensitized grains with silver halide or 
performing such surface covering with conversion of grain surface to 
different silver halide as described in U.S. Pat. No. 3,622,318 and 
British Pat. No. 635,841, or by forming deactivating sensitivity speck at 
grain surface by oxidation, etc. 
The present invention is characterized by the use of silver halide 
photographic emulsions which are internally sensitized and unfogged. The 
term "internally sensitized type" as used in this specification means 
emulsions containing silver halide grains capable of predominantly giving 
rise to internal latent images by image exposure, and conforming to the 
definition set forth in British Pat. No. 1,385,039 (page 2, lines 65-98). 
In order to identify an internally sensitized emulsion, one prepares two 
strips coated with the emulsion using a common exposure conditions. One of 
the strips is processed with surface developer X, while the other is 
processed with internal developer Y, and both are fixed at 20.degree. C. 
for 6 minutes. If the maximum density D.sub.max obtained by internal 
developer Y exceeds that obtained by surface developer X by a factor of 2 
or more, or if the photographic speed realized by internal developer Y is 
at least 5 times as great as that with surface developer X, then the 
emulsion is an internally sensitized emulsion. (Developers X and Y are 
employed for identifying the silver halide only. They are not the 
developers preferred for use in the present invention.) 
______________________________________ 
Internal Developer Y 
Metol (N-methyl-p-aminophenol sulfate) 
2.0 g 
Hydroquinone 8.0 g 
Sodium Sulfite (anhydrous) 
90 g 
Sodium Carbonate (monohydrate) 
52.5 g 
Potassium Bromide 5.0 g 
Potassium Iodide 0.5 g 
Water to make 1,000 ml 
Surface Developer X 
Metol (N-methyl-p-aminophenol sulfate) 
2.5 g 
Ascorbic Acid 10.0 g 
Borax 35.0 g 
Potassium Bromide 1.0 g 
Fixer 
Sodium Thiosulfate 150 g 
Sodium Sulfite 10 g 
Water to make 1,000 ml 
______________________________________ 
The internally sensitized silver halide emulsion used in the present 
invention can be obtained by any of the following methods: under such 
conditions as to suppress surface sensitization, defects are introduced in 
the crystal structure itself, or the grains are chemically sensitized 
during the course of physical ripening. Further, foreign metal ions such 
as, for example, rhodium ion, iridium ion, etc., are doped in the internal 
part of the crystal, or crystals once formed are converted by making use 
of the difference in the solubility product of silver salts. Such methods 
are described in detail in U.S. Pat. Nos. 3,317,322 and 3,761,276. The 
resulting emulsion can provide a positive silver image directly from a 
positive original when processed with a surface developer in the presence 
of a fogging agent. The average grain size for the silver halide is 
preferably about 0.1 to 5 microns, and in particular about 0.5 to 2 
microns. The silver halide grains can be spectrally sensitized. One can 
further incorporate in the emulsion additives such as mercapto compounds, 
triazole compounds, etc. 
In order to fog the emulsion upon development, various compounds can be 
used including fogging agent precursors. Representative examples are 
described in U.S. Pat. Nos. 2,588,982, 3,227,552, 3,615,615, 3,719,494 and 
3,734,738, etc. Specific examples include the following compounds: 
2-methyl-3-[3-(p-sulfophenylhydrazine)propyl]benzothiazolium bromide, 
2-methyl-3-(.beta.-hydroxyethyl)benzothiazolium bromide, 
p-methanesulfonamideethylphenylhydrazine, 
1,2-dihydro-3-methyl-4-phenylpyrido[2,1-b]benzothiazolium bromide, etc. 
Precursors such as 3-(2-acetylethyl)-2-benzylbenzoselenazolium bromide, 
etc., can be present in the emulsion layer. These fogging agents are 
preferably incorporated into the silver halide emulsion in an amount of 
about 100 mg to about 1,500 mg per mol of silver in the silver halide 
emulsion. 
Grain formation of silver halide can be performed in a binder such as 
gelatin, gelatin derivatives, polyvinylpyrrolidone, acrylamide containing 
polymers, cellulose derivatives, etc., which are used as the binder for 
the emulsion layer. In one embodiment of the present invention, one can 
use polymers that are tanning developable by the oxidation product (having 
a quinone form) of the developing agent. 
A suitable coating weight for the emulsion is from 0.1 to 10 g/m.sup.2. 
Where the surface developer works also as tanning developer, it has been 
surprisingly found that the fogging development used in the present 
invention provides not only a high quality positive image with perfectly 
clear highlight areas, but that the coexistent of the fogging agent 
precursor also promote the function of tanning. 
The internally sensitized silver halide photographic emulsion prepared in 
accordance with the present invention is not fogged prior to image 
exposure. As described in, for example, The Theory of the Photographic 
Process by C. E. K. Mees and T. H. James (Macmillan Co., third Edition), 
positive images can be directly reproduced from positive originals using 
an internally sensitized emulsion which has been found prior to image 
exposure. Furthermore, it is well known to those skilled in the art that 
such emulsions can be applied in the preparation of printing plates as 
taught, for example, in Japanese Patent Application (OPI) No. 15502/74 
(the term "OPI" as used herein refers to a "published unexamined Japanese 
patent application"). It is emphasized that this type of emulsion is based 
on an entirely different imaging mechanism, lacking high photographic 
speed and suffering from a low degree of highlight clearness as well as a 
poor shelf life and is not used in the present invention. In accordance 
with the present invention, the internally sensitized emulsion is the type 
not fogged prior to exposure. 
In a particularly preferred embodiment of the present invention, the 
internally sensitized silver halide emulsion coating described in detail 
hereinbefore contains a substantially water-insoluble, oleophilic resinous 
material in a finely dispersed state. 
An "oleophilic resin" is one which, when applied to a support in a 
thickness of about 2 microns or more (the caoted support is referred to as 
a specimen), the surface of the resin layer forms a substantially positive 
angle of contact with the support. As taught by Mitsuo Obana in Wetting on 
a Lithographic Printing PLate, Insatsu Zasshi (Journal of Printing), Vol. 
25, October issue, 1968, and by A. W. Adamson, Physical Chemistry of 
Surfaces, John Wiley & Sons, Inc., (1967), pp. 342-344, the angle of 
contact is defined as .theta.=-[.theta.o/w-.theta.w/o] wherein .theta.o/w 
is the angle of contact of kerosine in water as measured with a goniometer 
by the "captive bubble method" wherein fine particles (bubbles) of 
kerosine are brought into contact with the surface of the specimen 
immersed in water at 24.degree. C., and .theta.w/o is the angle of contact 
of water in kerosine as measured with a goniometer likewise bringing fine 
particles (bubbles) of water into contact with the surface of the specimen 
immersed in kerosine. Examples of such substantially water-insoluble 
oleophilic resins are such as shellac, polyamide resins, phenolic resins, 
polyvinyl acetal resins, linear polyurethane resins, phenolic novolak 
resins and polyester resins. Besides these resins, polyvinyl cinnamate 
resins and photosensitive polymers such as photosensitive polyesters can 
also be used. The following resins A, B and C are particularly preferred. 
A: Resins having a repeating unit of the following formula (I): 
##STR1## 
wherein Z is a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 
carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a carboxyl 
group. 
B: Resins formed by polycondensation of polyvalent unsubstituted phenol and 
ketone having 3 to 5 carbon atoms. 
C: Resins having a repeating unit of the following formula (II): 
##STR2## 
wherein R.sub.1 is a hydrogen atom or an alkyl group having 1 to 4 carbon 
atoms; X is a halogen atom; n is 1 or 2. 
Specific examples of the resin (C) include polymers of hydroxystyrenes such 
as polymers or copolymers of hydroxystyrene, chlorohydroxystyrene, 
bromohydroxystyrene, dibromohydroxystyrene and 
hydroxy-.alpha.-methylstyrene, copolymers with other monomers, and 
modified products of these polymers. Illustrative monomers copolymerizable 
with the hydroxystyrenes mentioned above include styrene, maleic 
anhydride, acrylonitrile, acrylic acid, methacrylic acid, ethyl acrylate, 
butyl acrylate, methyl acrylate, and hydroxyethyl metacrylate. 
Illustrative modified products of polymers or copolymers of hydroxystyrene 
include those wherein a hydroxyl group is esterified with an acid 
anhydride or acid halide (e.g., acetic anhydride, propionyl chloride, 
pivaloyl chloride, or benzoyl chloride), or etherified with an epoxy 
compound (e.g., glycidyl butyl ether or glycidyl tolyl ether), or 
urethanated with an isocyanate compound (e.g., phenyl isocyanate or 
hexamethylene diisocyanate). Preferably, these modified products contain 
at least 50 mol% of the unit represented by formula (II). The polymers 
have a weight average molecular weight of from about 500 to about 50,000, 
preferably from about 1,000 to about 20,000. These hydroxystyrene polymers 
can be synthesized by the methods described in J. Polym. Sci., A-1, 7, 
2175 (1969), and Maruzen Sekiyu Gijutsu Hokoku (Maruzen Sekiyu Technical 
Report), 21 1 (1976) or similar methods. Some of these polymers are 
commercially avaiable. 
Specific examples of the resin (B) include phenol/ketone resins; effective 
polyvalent phenols are resorcinol, catechol and pyrogallol, and effective 
aliphatic ketones are acetone and methyl ethyl ketone. These polymers have 
a weight average molecular weight of from about 500 to about 5,000 and can 
be synthesized by the methods described in Ind. Eng. Chem., 52, 324 (1960) 
and U.S. Pat. No. 3,635,709 or similar methods. Also effective are 
modified phenol/ketone resins wherein a hydroxyl group is modified in the 
same manner as in the case of the aforementioned polymers of 
hydroxystyrenes. Modified phenol/ketone resins preferably retain about 
half of the hydroxyl groups contained in the unmodified resins. 
The resin (A) include, for example, phenolic novolak resins and cresol 
resins, and can be synthesized by a well known methods. 
Of the resins (A), (B) and (C), resin (A) is particularly preferred. 
These resins are contained in the internal latent image type silver halide 
emulsion in the form of fine particles. To provide the fine particles of 
the resin, it is dissolved in an organic solvent whose solubility in water 
is not more than 10 wt% and is then dispersed in a hydrophilic colloid 
with the aid of an anionic surfactant such as sodium 
alkylbenzenesulfonate, taurine derivative or Turkey red oil. Illustrative 
hydrophilic colloids suitable for use in the emulsion layer are polyvinyl 
pyrrolidone, polyvinyl imidazole, polyvinyl alcohol, polyacrylic acid 
amide, and copolymers thereof, and gelatin or their derivatives. 
Particularly preferred are gelatin and their derivatives of the type 
described in U.S. Pat. Nos. 2,614,928, 2,763,639, 3,118,766, 3,132,945, 
and Japanese Patent Publication Nos. 5514/64 and 26845/67. These colloids 
may be used in combination with a high-boiling plasticizer such as 
tricresyl phosphate, dioctyl butyrate or dodecyl succinic acid ester. 
The olephilic resins are preferably dispersed in the hydrophilic colloid as 
particles having a size of about 0.01 to 10 microns. These resins can be 
contained in the internal latent image type silver halide emulsion in an 
amount of from about 0.1 to about 20 parts by weight per 10 parts by 
weight of the hydrophilic colloid. Preferably, they are present in the 
emulsion in an amount of about 1 to 10 and more preferably about 2 to 5 
parts by weight per 10 parts by weight of hydrophilic colloid. 
Suitable supports used in the present invention are aluminum supports 
having a hydrophilic surface including a plastic or a composite sheet 
where an aluminum sheet is laminated onto a film. The support is desirably 
subjected to a surface treatment, for example, a sand graining treatment, 
dipping in an aqueous solution of sodium silicate, potassium 
fluorozirconate, phosphates or the like, or anodization. 
Additionally, the aluminum plate which is treated by dipping in an aqueous 
solution of sodium silicate after sand graining as described in U.S. Pat. 
No. 2,714,066 and an aluminum plate which is firstly anodized and then 
dipped in an aqueous solution of a silicic acid alkali metal salt as 
described in U.S. Pat. No. 3,181,461 are preferably used in this 
invention. The above anodization treatment is carried out by passing a 
current through an aluminum plate in an aqueous or non-aqueous solution of 
an inorganic acid, e.g., phosphoric acid, chromic acid, sulfuric acid, 
boric acid, etc., an organic acid, e.g., oxalic acid, sulfamic acid, etc., 
or the salt thereof, or in a solution comprising two or more of the 
foregoing, particularly preferably in an aqueous solution of phosphoric 
acid or a mixture thereof. 
Silicate electric deposition as described in U.S. Pat. No. 3,658,662 is 
also effective. Moreover, an aluminum plate which is electrolyzed in an 
electrolyte of hydrochloric acid using an alternating current and then 
anodized in an electrolyte of sulfuric acid as described in British Pat. 
No. 1,208,224 is preferred. Furthermore, it is preferred from the 
standpoint of preventing scum in printing to provide on the aluminum plate 
anodized as described above an undercoating layer of a cellulose based 
resin containing a water-soluble salt of a metal, e.g., zinc, etc., as 
described in U.S. Pat. No. 3,860,426. 
A layer containing the water-insoluble, oleophilic resinous material used 
in the present invention can accept printing ink and thus constitute the 
image area of printing plate itself. The term "oleophilic resinous 
material" implies one that exhibits a positive value for 
.theta.=-[.theta.o/w-.theta.w/o] obtained from the contact angles 
.theta.w/o and .theta.o/w measured in accordance with the above. Specific 
examples of such materials include, for example, shellac, those resins set 
forth in British Pat. Nos. 1,460,978 and 1,505,739 which comprise 
hydroxyethyl acrylate or hydroxyethyl methacrylate as a chief recurring 
unit, polyamide resins such as are shown in U.S. Pat. No. 3,751,257, 
phenol resins as set forth in British Pat. No. 1,074,392, polyvinyl acetal 
including polyvinyl butyral, linear polyurethanes as set forth in U.S. 
Pat. No. 3,660,097, those resins containing an amino moiety such as 
polyaminostyrene, poly(alkylaminomethacrylate) or 
poly(alkylaminoacrylate), cellulose derivatives such as cellulose acetate, 
cellulose alkyl ether, cellulose acetate-phthalate, etc. 
Moreover, novolak type phenol resins are preferred, including 
phenol-formaldehyde resin, o-cresol-formaldehyde resin, 
m-cresol-formaldehyde resin, etc. More preferably, together with one of 
these phenol resins, one can use the condensation product of formaldehyde 
with a phenol or cresol substituted with a C.sub.3 -C.sub.8 alkyl group 
exemplified by t-butylphenol-formaldehyde resin. 
As the positive type non-silver photosensitive layer capable of giving rise 
to an oleophilic image, those containing o-quinonediazide compounds are 
particularly suited. 
Particularly preferred o-quinonediazide compounds are 
o-naphthoquinonediazide compounds, which are described in, for example, 
U.S. Pat. Nos. 2,766,118, 2,767,092, 2,772,972, 2,859,112, 2,907,665, 
3,046,110, 3,046,111, 3,046,115, 3,046,118, 3,046,119, 3,046,120, 
3,046,121, 3,046,122, 3,046,123, 3,061,430, 3,102,809, 3,106,465, 
3,635,709, and 3,647,443. Many other publications illustrate 
o-quinonediazide compounds that can be used in this invention with 
advantage. Particularly preferred are o-naphthoquinonediazidesulfonate 
ester or o-naphthoquinonediazidecarboxylate ester of aromatic hydroxy 
compounds as well as o-naphthoquinonediazidesulfonic acid amide or 
o-naphthoquinonediazidecarboxylic acid amide of aromatic amino compounds. 
Particularly effective compounds include a condensate of pyrogallol and 
acetone that is esterified with o-naphthoquinonediazidesulfonic acid as 
described in U.S. Pat. No. 3,635,709; a polyester having an end hydroxyl 
group that is esterified with o-naphthoquinonediazidesulfonic acid or 
o-naphthoquinonediazidecarboxylic acid as described in U.S. Pat. No. 
4,028,111, and a homopolymer of p-hydroxystyrene or a copolymer of 
p-hydroxystyrene and another copolymerizable monomer that is esterified 
with o-naphthoquinonediazidesulfonic acid or 
o-naphthoquinonediazidecarboxylic acid as described in British Pat. No. 
1,494,043. 
These o-quinonediazide compounds may be used independently, but they are 
preferably used in combination with an alkali-soluble resin. Suitable 
alkali-soluble resins include phenolic novolak resins such as a 
phenolformaldehyde resin, o-cresol-formaldehyde resin and 
m-cresol-formaldehyde resin. More preferably, as described in U.S. Pat. 
No. 4,123,279, these phenolic resins are used in combination with a 
condensate of formaldehyde with a phenol or cresol substituted by an alkyl 
group of C.sub.3 -C.sub.8 such as t-butylphenol-formaldehyde resin. The 
alkali-soluble resin is contained in an amount of from about 50 to about 
85%, preferably from 60 to 80%, based on the total weight of the 
photosensitive resist-forming composition. 
The photosensitive composition containing the o-quinonediazide compound may 
further contain a pigment, dye or plasticizer, as required. 
The layer containing an oleophilic resinous material or the posi type 
non-silver photosensitive layer which gives rise to an oleophilic image 
explained heretofore should be provided on an aluminum support at a 
coating rate of about 0.1 to 5 g/m.sup.2 on dry base. 
Next, the method of preparing a planographic printing plate from the 
photosensitive planographic plate produced in accordance with the present 
invention will be described. 
First of all, an image exposure is performed with light of such a spectral 
distribution and/or an intensity that only the internal type, unfogged 
silver halide emulsion can photographically respond. Such an image 
exposure can be done by contact or projection exposure with a transparent 
positive original, or by scanning with a laser beam. Then the exposed 
plate is subjected to a first development with a surface developer in the 
presence of a fogging agent. The fogging agent may be present either in 
the internal type silver halide emulsion coating or in the surface 
developer; among these two embodiments, the former is preferred whereby 
the surface developer is free from such a fogging agent. Via this 
processing, the exposed areas in the internal type silver halide emulsion 
coating are reduced to give a positive silver image. 
Various types of surface developer which are well known to those skilled in 
the art can be applied to the present invention. Though surface developers 
should contain substantially no silver halide solvent, use of such a 
solvent is permitted, however, to improve the stability of the developer 
(shelf life expansion) provided that the finished developer can give a 
maximum density not greater than 0.4 in the exposed areas. Additionally, 
the surface developer desirably does not cause cracking of the silver 
halide grains, nor promote recrystallization to a substantial degree. 
The principal examples of reducing agents for the developer include 
hydroquinone derivatives, catechols, aminophenols, 3-pyrazolidones, 
ascorbic acid, redactones, p-phenylenediamines, etc. Such compounds may be 
used in combination and be present in the photographic material. Suitable 
compounds include: p-phenylenediamine derivatives; 
N,N-diethyl-p-phenylenediamine hydrochloride, 
2-amino-5-diethylaminotoluene hydrochloride, 
2-amino-5-(N-ethyl-N-laurylamino)toluene, 
4-[N-ethyl-N-(.beta.-hydroxyethyl)amino]aniline sulfate, 
2-methyl-4-[N-ethyl-N-(.beta.-hydroxyethyl)amino]aniline sulfate, 
N-ethyl-N-(.beta.-methanesulfoaminoethyl)-3-methyl-4-aminoaniline 
sesquisulfate, monohydrate which is set forth in U.S. Pat. No. 2,193,015, 
N-(2-amino-5-diethylaminophenylethyl)methanesulfonamide sulfate set forth 
in U.S. Pat. No. 2,592,364, N,N-dimethyl-p-phenylenediamine hydrochloride, 
4-amino-3-methyl-N-ethyl-N-methoxyethylaniline set forth in U.S. Pat. No. 
3,656,950, 4-amino-3-methyl-N-ethyl-N-.beta.-ethoxyethylaniline, 
4-amino-3-methyl-N-ethyl-N-.beta.-butoxyethylaniline, etc. The last few 
compounds may be used also in the form of salt including sulfate, 
hydrochloride, sulfite, p-toluenesulfonate, etc. 
In the developer there can be incorporated an anti-foggant or a development 
suppressing agent, or they may be present in the photosensitive member, if 
desired. Particularly desirable results are realized when the first 
development is carried out in the presence of an anti-foggant as described 
in U.S. Pat. No. 2,497,917 typical examples being benzotriazole compounds, 
benzoimidazole compounds, benzothiazole compounds, heterocyclic thione 
derivatives, triazole compounds, benzoxazole compounds, pyrrole compounds, 
etc. 
The pH of the developer preferably lies in the range of from about 7 to 15. 
A relatively wide range of developing temperatures are permitted. 
Typically it is from about 15.degree. to 40.degree.. 
The emulsion coating is fixed immediately after the first development. 
Where the surface developer functions as a tanning developer, the 
undeveloped silver halide emulsion can be washed off with warm water 
instead of fixing. 
Where the photosenstive lithographic plate of the invention comprises layer 
(a) of an oleophilic resinous material, the latter method of development 
is adapted to provide a resist image, and then the unprotected region of 
the oleophilic resin-containing layer is eliminated with a suitable 
solvent to leave the hydrophilic surface of the aluminum support exposed. 
On the other hand, when layer (a) is a non-silver, positive type 
photosensitive layer, the silver image formed in the internal type silver 
halide emulsion coating is used as an optical mask through which radiation 
active to the underlying non-silver layer is given. Then the plate is 
processed with a second developer capable of developing the non-silver 
photosensitive layer whereby the hydrophilic surface of the aluminum 
support is exposed. In the latter embodiment, one can remove, prior to the 
second development and after the irradiation with light active to the 
non-silver layer, the internally sensitized silver halide emulsion coating 
in its entirety. For the development of a non-silver photosensitive layer 
comprising an o-quinonediazide compound, the aqueous solution of an alkali 
metal silicate is recommended. Some typical formulations for such 
developers are found in German Patent Application (OLS) No. 2,846,256.

Below, there are illustrated some practical examples of the present 
invention, which is, as a matter of course, not limited thereto. In the 
examples, all percentages are based on weight unless otherwise designated. 
EXAMPLE 1 
A 2S grade aluminum sheet mechanically surface grained was immersed in a 2% 
aqueous sodium hydroxide solution kept at 40.degree. C. for 1 minute to 
partially etch the surface. After rinsing with water, the sheet was 
immersed in a mixture of sulfuric acid and chromic acid for about 1 minute 
whereby a fresh aluminum surface appeared. Then the sheet was subjected to 
anodizing in a 20% sulfuric acid bath kept at 30.degree. C. with a passage 
of electric current of 1.5 D.C. volt with a current density of 3 
A/dm.sup.2 for 2 minutes, and then to water rinse followed by drying. A 
coating mixture for a non-silver photosensitive layer of the following 
composition was applied on the sheet by means of roll coater so as to give 
a dry coating rate of 2 g/m.sup.2. The coated sheet was dried at 100 
.degree. C. for 2 minutes. 
______________________________________ 
The naphthoquinone-1,2-diazide (2)-5- 
2.5 g 
sulfonic acid ester of an acetone/pyrogallol 
resin prepared in accordance with Example 1 
of U.S. Pat. No. 3,635,709 
Hitanol #3110 (a cresol/formaldehyde resin, 
5.0 g 
produced by Hitachi Chemical Ind.) 
Methyl ethyl ketone 75 g 
Cyclohexanone 60 g 
______________________________________ 
Next, photosensitive coating mixture (I) of the following composition was 
applied on the plate in a continuous mode so as to give a coating weight 
of 5 g/m.sup.2 on dry base whereafter drying was performed with hot air at 
90.degree. C. as the final step. The resulting sample is Sample No. 1. 
45 g of phenol/formaldehyde resin with a commercial designation MP120HH (a 
product of GUN-EI Chemical Ind., Ltd.) was dissolved in a mixture of 330 g 
ethyl acetate and 120 g methyl ethyl ketone, to which 20 g of tricresyl 
phosphate was further dissolved. This solution was emulsified into an 
aqueous solution comprising 600 ml of an aqueous 10% gelatin solution, 60 
ml of an aqueous 10% solution of sodium nonylbenzene sulfonate and 150 ml 
of a 10% methanol solution of turkey red oil. Using this dispersion, 
another coating fluid was prepared as follows: 
Photosensitive Coating Mixture (I) 
______________________________________ 
The dispersion described above 
1,300 g 
A silver iodobromide crude emulsion 
2,000 g 
(internally sensitized type; containing 
45 g gelatin and 0.59 mol of silver 
iodobromide per 1 kg, the iodide content: 
2 mol %, and the average grain size: 
1.2 microns) 
Potassium iodide 0.5% aqueous solution 
80 ml 
2% aqueous solution of 2-methyl-3-(.beta.- 
40 ml 
hydroxyethyl)benzothiazolium bromide 
Water 1,300 g 
______________________________________ 
Sample No. 1 was converted into a lithographic printing plate by the 
following procedures. A reflective positive original containing text was 
projected onto the sample by means of a process camera provided with a 
light source of 500 lux through a lens with an opening of F-11 for 20 
seconds. The plate precursor was then fed into an automatic processor to 
be processed as follows. First Developer (I) of the following composition 
was supplied to the processor at a temperature of 32.degree. C. for 60 
seconds, then brushing was carried out with the use of 45.degree. C. hot 
water for 30 minutes to eliminate the non-image areas. A positive image 
resulted. 
Developer (I) 
The following two fluids I-a and I-b were mixed just before use in equal 
volumes to give Developer (I). 
Fluid I-a 
______________________________________ 
Pyrogallol 6 g 
p-Monomethylaminophenol Hemisulfate 
2 g 
Citric Acid 2 g 
Water to make 1,000 ml 
______________________________________ 
Fluid I-b 
______________________________________ 
Sodium Carbonate (monohydrate) 
225 g 
Potassium Bromide 3 g 
Sodium Hexametaphosphate 2 g 
Water to make 1,000 ml 
______________________________________ 
Then, the plate precursor was passed through an exposure station installed 
with three reflector type mercury lamps for 15 seconds, and then processed 
with Developer (II) of the following composition kept at 30.degree. C. for 
30 seconds. Finally, the plate was coated with 14.degree. Be gum arabic 
solution to give a finished printing plate. 
Developer (II) 
______________________________________ 
JIS-1 Grade Sodium Silicate 
10 g 
Sodium Metasilicate 5 g 
Purified Water 180 ml 
______________________________________ 
When the plate was subjected to printing with a Heidel GTO printer, 
printing plates with excellent edge sharpness were obtained. 
EXAMPLE 2 
On the same aluminum support as described in Example 1, the non-silver 
photosensitive coating mixture shown in Example 1 was coated to give a 
coating weight of 2 g/m.sup.2 after drying. 
Photosensitive coating mixture (II) of the following composition was then 
overcoated in a continuous manner so as to provide a coating rate of 8 
g/m.sup.2 after drying. The resulting plate is designated Sample No. 2. 
Photosensitive Coating Mixture (II) 
______________________________________ 
A dispersion of an oleophilic phenol/ 
total amount 
formaldehyde resin MP120HH (a product 
of Gun-Ei Chemical Ind.) obtained by 
dissolving 20 g of said resin together 
with 20 g dioctyl adipate in a mixture 
comprising 154 ml ethyl acetate and 
56 ml methyl ethyl ketone, which was 
dispersed under rapid stirring with 
a homogeneous blender into a mixture 
comprising 280 g of a 10% gelatin 
solution, 28 ml of a 10% aqueous 
solution of sodium dodecylbenzene- 
sulfonate and 70 ml of a 10% methanol 
solution of turkey red oil 
A silver iodobromide crude emulsion 
1,000 g 
(internally sensitized type; containing 
55 g gelatin and 0.6 mol of silver 
iodobromide per 1 kg emulsion, the 
iodide content: 2 mol %, and the 
average grain size: 1.2 microns) 
Potassium iodide 0.5% aqueous solution 
20 ml 
A 0.15% methanol solution of 3-ethyl- 
65 ml 
5-[2-(1-ethyl-4-methyltetrazolidine- 
ethylydine]-2-thioxo-4-oxazolydine-one 
A 0.5% aqueous solution of 4-hidroxy-6- 
21 ml 
methyl-1,3,3a,7-tetrazaindene 
A 2% aqueous solution of 2,4-dichloro- 
35 ml 
6-hydroxy-s-triazine 
______________________________________ 
Sample No. 2 was converted into a lithographic printing plate via the 
following procedures. A reflective positive original containing text was 
projected onto the sample by means of a process camera provided with two 
500 lux lamps with a lens aperture of F-22 for about 30 seconds. The plate 
was then fed into an automatic processor and processed as follows. First 
Developer (III) of the following composition was supplied to the processor 
at a temperature of 30.degree. C. for 20 seconds, and then Fixing Solution 
(I) shown below was fed at room temperature for 10 seconds. 
Developer (III) 
______________________________________ 
Water 700 ml 
Hydroquinone 10 g 
Sodium Sulfite 30 g 
4-Methyl-1-phenyl-3-pyrazolidone 
1 g 
Sodium Orthophosphate 40 g 
Sodium Hydroxide 10 g 
p-Tolylhydrazine 0.2 g 
5-Nitrobenzotriazole 0.02 g 
Water to make 1,000 ml 
______________________________________ 
Fixing Solution (I) 
______________________________________ 
Water 700 ml 
Ammonium Thiosulfate 224 g 
Sodium Sulfite 20 g 
Water to make 1,000 ml 
______________________________________ 
Then the plate was passed through an exposure station installed with three 
reflector type mercury lamps for 15 seconds, and then processed with 
Developer II set forth in Example 1 at 30.degree. C. for 30 seconds. 
Finally, the plate was coated with 14.degree. Be gum arabic solution to 
give a finished printing plate. 
The plate was set up in a Heidel KOR printer for printing, giving 
high-quality prints of 100,000, free of smudge and with sharp edges. 
Separately, the silver iodobromide crude emulsion used in the example was 
coated on a cellulose triacetate film support to give a coating thickness 
of 3 microns. Image exposure was performed in strictly the same manner as 
set forth above, and one exposed piece was developed with the internal 
developer Y described hereinbefore, and another piece with the surface 
developer X described hereinbefore at 20.degree. C. for 6 minutes. The 
both pieces were fixed for 5 minutes. While D.sub.max obtained by 
developer Y was 2.3, that obtained by developer X at the same exposure 
amount was only 0.15. From these results, the crude emulsion used was 
confirmed to be of the internally sensitized type. 
EXAMPLE 3 
A 2S grade aluminum sheet mechanically surface grained was immersed in a 2% 
aqueous sodium hydroxide solution kept at 40.degree. C. for 1 minute to 
etch the surface fractionally. After rinsing with water, the sheet was 
immersed in a mixture of sulfuric acid and chromic acid for about 1 minute 
whereby a fresh and clean aluminum surface was exposed. Then, the sheet 
was subjected to anodizing in a 20% sulfuric acid bath kept at 30.degree. 
C. with a passage of 1.5 volt D.C. electric current with current density 
of 3 A/dm.sup.2 for 2 minutes. After water rinse, the sheet was immersed 
in a 10% phosphoric acid solution for 30 seconds at 50.degree. C., 
followed by another water rinse and immersion in a 2% sodium silicate (JIS 
3 grade) solution kept at 70.degree. C. for 2 minutes. After water rinse, 
the sheet was heated for drying. The dried sheet, after cooled to room 
temperature, was coated with the following subbing fluid by a roll coater. 
Subbing Fluid 
______________________________________ 
Carboxymethyl Cellulose 2.5 g 
Nickel Acetate 2.5 g 
Water 1,000 ml 
______________________________________ 
After rinsing with water and drying, an oleophilic resin layer was provided 
by coating Vilon 300 (a commercial product available from Toyobo Co., a 
saturated polyester resin) dissolved in methyl ethyl ketone to give a 
dried coating rate of about 1 g/m.sup.2. On this coating, Photosensitive 
Coating Mixture (I) used in Example 1 was overcoated and dried to give a 
coating weight of 6 g/m.sup.2 on a dry base. The finished member is 
designated Sample No. 3. According to the method described in Example 1, 
the member was imagewise exposed. The member was developed with Developer 
(I) at 32.degree. C. for 60 seconds, subjected to a washing-off operation 
for the non-image areas performed at 40.degree. C. for 30 minutes to give 
rise to a positive image. After drying, a 15% aqueous solution of Demol EP 
(a product of Kao Soap Co.) was spread over the entire surface of the 
sheet with the aid of a piece of absorbent cotton, and the sheet surface 
was lightly rubbed for about 30 seconds to remove the Vilon 300 layer at 
the non-image areas. Finally, the sheet was coated with Gum GN-3 made by 
Fuji Photo Film Co. to provide a printing master. When this master was set 
up in a Hamade 900 CDX printer and printed, 20,000 prints were possible. 
While the invention has been described in detail and with reference to 
specific embodiments thereof, it will be apparent to one skilled in the 
art that various changes and modifications can be made therein without 
departing from the spirit and scope thereof.