Developer for photographic materials used in the graphic arts
United States Patent [1 1 Okutsu et al.  
 [ Apr. s, 1975 1 DEVELOPER FOR PHOTOGRAPHIC MATERIALS USED IN THE GRAPHIC ARTS [75] Inventors: Eiichi Okutsu; Haruhiko Iwano,  
 both of Minami Ashigara-shi, Kanagawa, Japan [73] Assignec: Fugi Photo Film Co., Inc..  
 Minami Ashigara-shi, Kanagawa, Japan [22] Filed: Feb. I, 1973 [2]] Appl. No.: 328,808  
 [30] Foreign Application Priority Data Primary Examiner-Mary F. Kelley Attorney, Agent. or FirmSughrue, Rothwell, Mion, Zinn &amp; Macpeak [57] ABSTRACT A developer for photographic materials used in the graphic arts which has excellent preservability but no adverse influence upon image quality containing at least one compound represented by the general formula wherein R R R and R which may be the same or different, each represents H, OH, CH;, or COOM with M being a hydrogen atom. a water-soluble cation or a lower alkyl group of not more than 4 carbon atoms.  
 6 Claims, No Drawings DEVELOPER FOR PHOTOGRAPHIC MATERIALS USED IN THE GRAPHIC ARTS BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION This invention relates to a developer for photographic materials for the graphic arts. More particu larly, this invention is concerned with such a developer having excellent preservability.  
 2. DESCRIPTION OF THE PRIOR ART In general. in the graphic arts field. where it is desired to make photographic line and halftone reproductions. a high contrast photographic light-sensitive material called a lithographic light-sensitive material. and a developer different from usual black-andavhite developers. that is. an infectious developer (or lithodeveloper). are used. By using such particular developers. density changes in the continuous gradation of a copy can be divided into dots which change in surface area in response to the density.  
  A photographic silver halide material has the property that it produces. in addition to maximal and minimal density portions for the formation of dot images. areas of intermediate density. so that when the combination of a high contrast photographic light-sensitive material and a standard black-and-white developer is used an area of density gradation with a density less than the dot images. that is. fringe. is produced around the images. which is not desirable in plate making.  
  Fringe can be avoided to a certain extent by using a so called infectious developer comprising a dihydroxy benzene such as hydroquinone as a developing agent in combination with sodium sulfite and paraformaldehyde.  
  With normal developers. hydroquinone is converted during the development process to quinone. which is further reacted with sodium sulfite to give sodium hydroquinone monosulfonate. Sodium hydroquinone monosulfonate is of poor reducing power because its potential is higher than that of hydroquinone. and thus of little effect as a developing agent. Accordingly. with increased formation of sodium hydroquinone monosulfonate development suddenly ceases, thereby forming fringe.  
  On the other hand, in the case of an infectious developer. which has a low sodium sulfite content and con tains carbonyl groupbearing compounds such as paraformaldehyde. the free sulfite ion concentration is maintained low as a result. for example. of the reaction shown by the following equation:  
 Accordingly. it becomes difficult for the quinone (produced from hydroquinone during development) to react with the sulfite to give sodium hydroquinone monosulfonate. with the result that the concentration of the quinone increases. Semiquinone is produced as a result of a disproportionation reaction between quinone and hydroquinone. and due to its high developing activity the Semiquinone reduces silver halide and oxidizes itselfinto quinone. This process is infectiously repeated to give rapid development. which may be the predominant cause of development with high gamma values found in development of this type [see Yule,J. Frank. Inst.&#34; 239,221. (1945)].  
  Although it is known that a sulfite should function as a preservative in a developer. it is necessary to keep sulfite concentration low in order to attain a desired litho-effect. as described above. Thus, an infectious developer has a serious disadvantage in that it has esscn tially poor preservability. and the addition of sodium sulfite to improve the preservability results in a deterioration in dot quality. In an attempt to improve the preservability. it has been suggested to add. in place of or in addition to a sulfite. antioxidants other than a sulfite. For instance. it was proposed to add ascorbic acid to an infectious developer (see British Patent No. 928.390). However. due to its poor stability. ascorbic acid is decomposed with ease. particularly in a developer which contains metal ions such as copper ions and iron ions. Moreover, the resulting developer is of insufficient preservability. In addition. the use of ascorbic acid presents such drawbacks that it delays development to some extent and the addition of too large a quantity thereof leads to a deterioration in dot quality.  
 SUMMARY OF THE INVENTION Accordingly. one object of the invention is to provide a developer for printing photographic materials in the graphic arts field where it is desired to make photographic line and halftone reproductions. which dcvcloper has excellent preservability but no adverse influence upon image or dot quality (such materials are occasionally referred to as dot photographic materials).  
  Another object of the invention is to make it possible to manufacture a photographic printing plate which is of stable quality over a long period of time using a dcveloper having high preservability.  
  Another object ofthe invention is to simplify the handling and storing of such a developer.  
  Still another object of the invention is to reduce the make-up amounts of developer required during infectious development.  
  After research to reach the objects enumerated above we found that when at least one gamma-pyrrone represented by the following general formula wherein R R R and R which may be the same or different. each represents H. OH, CH,-; or COOM. with M being a hydrogen atom. a vvatersoluble cation e.g.. ammonia or an alkali metal such as sodium or potassium. or an alkyl group having four or less carbon atoms. is added to an infectious developer the preservability of the developer is remarkably improved without any adverse influence upon dot quality.  
 DETAILED DESCRIPTION OF THE INVENTION Representative examples of the compounds of the abovedescribed general formula are shown in the following. The invention is, of course. not limited to the use of such compounds.  
 Compound 1 Compound 2 Compound 3 Q a El Compound 4 Hill 011 Compound 5 CH O CH 3 U 3 Compound 6 H000 ul nj COOH 0 Compound 7 O COCH 0 Compound 8 COOCH3 Compound 9 0 cooc a The compounds ofthe present invention may be used in the form of their water-soluble salts such as the potassium. sodium and ammonium salts, or salts with sulfuric acid or hydrochloric acid.  
  As used in this specification, the term infectious developer denotes a developing composition essentially comprising. before use a dihydroxybenzene as a developing agent, an alkali a small amount of a sulfite and a sulfite ion buffer, the compound or compounds according to the invention being added to such a composition.  
  As dihydroxybenzenes used as developing agents, one may use any suitable compounds known for such purpose in the photographic arts. Examples of such compounds include hydroquinone, chlorohydroquinone, bromohydroquinone, isopropylhydroquinone, trihydroquinone, methylhydroquinone, 2,3- dichlorohydroquinone and 2,S-dimethylhydroquinone, of which hydroquinone is most commonly used.  
  These developing agents may be used either individually or as mixtures. The amount of the developing agent added can be in the range of from about 5 to about &#39;50 grams, preferably 10 to 30 grams, per liter of developer.  
  The sulfite ion buffer is used in an amount effective to keep the sulfite present in the developer at a low concentration level. Examples of such sulfite ion buffers include aldehydealkali hydrogen sulfite adducts such as formaldehyde-sodium hydrogen sulfite adduct, ketone-alkali hydrogen sulfite adducts such as acetonesodium hydrogen sulfite adduct, carbonyl bisulfiteamine condensation products such as sodium bis(2- hydroxyethyl )aminomethanesulfonate and the like. The sulfite ion buffer used in the invention is in no way limited to these specific examples. Thus, for example, each of the components in the adducts or condensation products may be added separately to the developer. The amount of the sulfite ion buffer can range from about 13 to about grams, and preferably from 30 to 60 grams, per liter of the developer used. The sulfite ion buffers are well known materials and many examples thereof are described in US. Pat. Nos. 3,294,540; 3,516,830; 3,573,914; 3,615,524; and 3,625,689.  
  An alkali is added to the developer to make the developer alkaline, more preferably to adjust the pH to 9 or more. One may employ any amount or kind of alkali known to the art which is suitable for the pH adjustment purpose, e.g., sodium hydroxide, potassium hydroxide and/or sodium carbonate.  
  In infectious developers in general it is normal to employ a sulfite ion buffer due to the inherent need for a low free sulfite ion content. In general. it is also possible to regulate the free sulfite ion concentration by adding to a sulfite ion buffer 5 grams. or less. per liter of the developer used. of an alkali sulfite such as so dium sulfite. In the usual case. 3 grams or less of a sulfite is in general added. and by this addition the preservability of the developer is improved to some extent. although dot quality more or less deteriorates. These effects are also maintained in this invention. but preservability is greatly improved by the addition of compounds according to the present invention.  
  Usually in any infectious developer the amount of free sulfite is less than 5 g/l.  
  The infectious developer according to the invention may contain. if desired or needed for some special development, in addition to the components specified above a pH buffering agent such as a water soluble acid. an alkali or salt. and/or a development restrainer such an alkali halide. Certain alkalis not only make the developer alkaline but also function as a pH buffering agent and development restrainer. The developer may contain an organic anti-fogging agent such as benzotriazole and l-phenyl-5-mercapto-tetrazole. a polyalkylene oxide. an amine compound and/or an organic solvent (in amounts ranging from 0 to 300 ml per liter of the developer) such as triethylene glycol. dimethyl formamide. methyl alcohol and cellosolve. With regard to the exact composition and amount of the abovementioned materials added to the infectious developer. one may use any of these components in an amount as is known in the art.  
 The compounds according to the invention may be used alone or as a mixture of two or more of such compounds. The amount of the compound of the invention used is generally within the range of0.1 to 30 grams per liter of the developer used and preferably within the range of from 0.5 to grams.  
  Development using the improved developer of the present invention is conducted at the temperature/time conditions for prior art infectious developers.  
  In the case of using developing compositions in liquid or powder form where the ingredients to be incorporated into the final developer are previously formulated into forms such that they can be used simply by mixing them with a diluent or by dissolving them in a solvent. it is efficient to add the gammapyrrone compounds of the invention to said compositions. This is so particularly when the formulated compositions are in liquid form where the addition of the compounds of the invention remarkably increases the preservability of the liquid compositions. Furthermore, in the case of liquid compositions of the type described above it is impossible. from the nature of the compositions. to incorporate thereinto sufficient amounts of salts such as a carbonyl bisulfite to attain satisfactory preservability. and thus it is difficult to obtain stable developing compositions. Accordingly, it is in particular desirable to add compounds of the invention to such liquid compositions since they will improve preservability. The liquid compositions in general consist of two compositions of liquid agents. in the usual case one containing a developing agent and the other containing an alkali.  
  The compounds according to the invention may be added to either composition. although it is in particular efficient to add them to the composition containing a developing agent since by the addition in this manner the preservability of the liquid developing composition and thus of the infectious developer obtained by diluting the composition are remarkedly improved.  
  Solvents for such developing compositions include any of those solvents known in the art. for example water. benzyl alcohol. ethylene glycol. diethylene glycol. triethylene glycol. glacial acetic acid or mixtures of such solvents.  
  In a similar manner. the compounds of this invention may be added to a developer for printing photographic materials to improve the preservability of the developer used.  
  Printing light-sensitive materials which may be used in the invention include any silver halide emulsion such as silver chloride. silver chlorobromide and silver chloroiodobromidc emulsions. of which a silver chlorobromide or silver chloroiodobromide emulsion containing 51) mole /1 or more silver chloride is in particular suitable. These silver halide emulsions may contain. as a dispersing agent. one or more hydrophilic colloidal substances. for example. gelatin or derivatives thereof such as gelatin modified with phthalic acid or malonic acid. cellulose derivatives such as collodion. hydroxy ethyl cellulose and carboxymethyl cellulose. soluble starches such as dextrin and alkalized starch. and hydrophilic polymers such as polyvinyl alcohol. polyvinyl pyrrolidonc. polyacrylamide and polystyrene sulfonic acid.  
  While there is no critical limitation on the emulsion systems used. preferred emulsions are those where the silver halide grain size is (1.1 to 1 micron and which contain a preferred amount of a hydrophilic colloid material such as gelatin in an amount of 30 to g per l mol of silver halide.  
  Furthermore. the silver halide emulsions may also contain hydrophobic polymers such as polyalkyl acrylates. polymethacrylates. polyacrylic acid and copolymers of an alkyl acrylate and acrylic acid. or gelatinplasticizers such as glycerin trimethanolpropane.  
  The emulsions used in the light-sensitive materials can be. when they are prepared or applied. sensitized by varied methods. For example. they may be chemically sensitized in various manners known to the art. for example by using sodium thiosulfate. alkyl thiourea or like sulfur-containing compounds. and/or a compound of gold such as a complex of an aurous compound and thiocyanic acid. They may also contain compounds of a heavy metal such as platinum, palladium. iridium. rhodium. cadmium or the like. Alternatively. they may be orthochromatically or panchromatically sensitized by adding a color sensitizer such as a cyanine dye or a merocyanine dye thereto.  
  The emulsions may contain dot quality-improving agents such as polyalkylene oxides and amine compounds (see Japanese Pat. Publication 14.402/64. which is the equivalent of U.S. Pat. No. 3.288.612. German Patent Application Laid Open to Public lnspection No. 1. 932. 882. Japanese Pat. Publication 23.466/65. equivalent to U.S. Pat. No. 3.345.175). sodium benzene thiosulfate and benzotriazole or 1. 3 3a. 7-tetrazaindene derivatives (see Japanese Patent Publication No. 15.715/64, equivalent to U.S. Pat. No. 3.375.114. and Japanese Patent Publication 17.903). They may also be hardened with a hardener such as formaldehyde. dimethylol urea. 2.. 4-dichloro-6-hydroxy- 1. 3. S-triazine (U.S. Pat. No. 3.325.287) or mucochloric acid and may contain a surface active agent such as saponin as a coating aid. Moreover. they may include a development improver such as a 3- pyrazolidone or pyrazolone derivative. and/or a de\ elopment accelerator such as a quaternary ammonium salt or a cationic surface active agent.  
  As the support for the emulsions used in the invention. one may employ any suitable support known in the art. for example glass. cellulose acetate. polystyrene. polycarbonate and polyethylene telephthalate.  
  Although the reason is not known at present why the preservability of the developer for printing photographic materials is improved by adding the compounds of the invention thereto. it is evident. as shown in examples illustrated below. that the compounds of the invention are much more superior from the viewpoint of preservation to any of the prior art preservatives such as sodium sulfite and ascorbic acid. and afford excellent dot quality at the same time.  
  To illustrate the effectiveness of the invention in more detail. specific examples thereof will now b given.  
 EXAMPLE l Developer A:  
 Sodium carbonate (monohydrate) X g. l t)rllltllLlCllyLlC-SOtllLllll hydrogen sullite adduct (\5 g. Potassium bromide g. Hydroquinone lo g. Sodium sulfitc I g. Boric acid b g.  
 Water to make Developer B:  
 Developer A plus 2.0 g Compound l of the invention Developer C:  
 Developer A plus 3.0 g sodium sullite Developer D:  
 Developer A plus l g LfilStIUl&#39;l lC acid The resulting photographic properties are shown in speed as with Developer A. &#39;l&#39;hc dot quality was classified into 10 equally spaced classes on a visual evaluation basis. where 10 was excellent and l was extremely poor. &#39;lhe term &#34;aged developer&#34;- means 1 liter of developer placed in a l liter beaker and kept in contact with thc air by allowing the developer to stand at room temperaturc for three days.  
  lhe results shown in l&#39;able l reveal that the relative speed of the aged de\eloper without any additive is remarlsably reduced in comparison with the aged developers containing additives. For comparison. Developer with 3.0 g sodium sulfite added thereto was aged with the result that the relative speed thereof reduced. al though less than Developer A. to a considerable extent. and in this case the dot quality obtained. even in the fresh developer. was relatively poor. Also. for comparison. Developer D to which 1.0 g Lascorbic acid. a preservative well known in the art. was added was aged with the result that its relative speed reduced approximately the same extent as Developer C. indicating that Developer D is not satisfactory. In contrast thereto. Devcloper B to which 1.0 g of Compound 1 of the present invention was added was aged to give the lowest degree of reduction in sensitivity without any deterioration in dot quality.  
 EXAMPLE 2 A silver halide emulsion consisting of 75 mol 9? of silver chloride and 0.2 mole &#34;/1 of silve iodide. remainder silver bromide. was subjected to gold-and sulfur-sensitizations followed by optical sensitization with 3- carboxymethyl-S-l2-(3- ethylthiazolinylidene)ethylidene] rhodamine. To the sensitized emulsion were added a polyoxyethylene bearing ethylene oxide groups. nonyl phenyl ether, a development accelerator as described in Japanese Patent Publication 23465/ (of the formula N-CH 2CH2CH2CH-NHCONH l 2 5 on and mucochloric acid. and the mixture was mixed with a polymethyl methacrylate polymer (molecular weight about 2000) and applied onto a film base to prepare a litho-film. Using the resulting film. sensitometry was 50 lable 1. performed by exposing the film to a sensitometric opti- Table l Deieloper Additive Amount .&#39;l ilnc of Dot quality Relative in g l Development Speed in min.  
 Fresh Aged Developer Developer A None 1.75 l0 l00 3) B Compound I 2.0 1.75 10 100 Sodium sullite 3.0 3 3 70 D L-ascorbic acid HI 3 8 100 65 The relative speed obtained by development for2. 75 (,5 cal wedge through a magenta contact screen minutes with Developer A was taken as 100. and the times of development for Developers B. C. and D set to he ones at which their relative speed reached the same lines). and development of the exposed film was carried out &#39;at a temperature of 20C in Developers E or F. the formulaeof which are shown below:  
 Developer E: Solution [1 Distilled water 60 ml. Triethylcne glycol 35 ml. Formaldehyde-sodium hydrogen sulfitc adduct 40 g. Hydroquinone 18 g. Sodium sulfitc 3 g. Distilled water to make 125 ml. Solution ll: Distilled water 80 ml. Potassium carbonate 30 g. Sodium hydroxide 3 g. Boric acid 3 g. Distilled water to make I25 ml.  
  Before use, Solution l was added to 750 ml water and then Solution ll added to make 1 liter of developer ready for use.  
 EXAMPLE 4 To each of two automatic developing machines for making printing plates was charged liters of Developer E in Example 2, and 200 sheets of a litho-film were processed using each of the machines, with 60 ml per sheet of the litho-film of a supplementary or makeup soluttion being added, the formula of which supplementary solution is shown below:  
  15 Developer F To Solution I used in preparing Developer E was ppl t&#39; Solution I:  
 added 3.0 g of Compound 2 according to the present Distilled water 5 invention. and the mixture mixed with Solution ll with y dif h d water added to make 1 liter. 20 mgen The resulting photographic properties are shown in Hydroquinone 17 g. Table ll. Sodium sulfitc 3 g Table 2 Developer Additive Amount Time of Dot quality Relative in g/] Development Speed in min.  
 Fresh Aged Developer Developer E None 2.75 l() 100 28 F Compound 2 3.0 2.75 10 100 Developer F containing Compound 2 according to Distilled water to make It? inl. the invention showed less reduction in relative speed in {li m] comparison with Developer E containing no additive. poitqssium cnrhsmdte 40 g All terms in Table 2 have the same meaning as in Ex- Sodium hydwxlgle 3 Potasslum bromide 2 g.  
 ample Distilled water to make 167 ml.  
 EXAMPLE 3 Using a commercially available litho-film, sensitometry was conducted by exposing the film to a sensitometric optical wedge through a magenta contact screen lines) and development of the exposed film carried out at a temperature of 27C in Developer G, H, l, J or K, the formulae of which are shown below:  
 Developer G:  
 Sodium carbonate Formaldehyde-sodium hydrogen sulfite adduct Potassium bromide Boric acid Hydroquinone Sodium sulfite Sodium hexametaphosphate Water to make Developers H. l, .l and K To Developer G was added Compound 3, 4, 5 or of the present invention, respectively.  
  The resulting photographic properties are shown in Table 3.  
  Before use, Solution 1 was added to 666 ml of water and then Solution II was added to make 1 liter of developer ready for use.  
  After development of the litho-film, one of the two automatic developing machines was allowed to stand for 64 hours while the other was allowed to stand, after addition of 50 g. of Compound 7 according to the invention, for the same period of time. Subsequently, lithofilm was developed using each of the two automatic developing machines to find, in the case of the developing machine to which the compound of the invention had been added, no reduction in relative speed but, in the case of the other developing machine, a marked reduction in relative speed.  
 EXAMPLE 5 Using a commercially available litho-film, sensitometry was conducted by exposing the film to a sensitometric optical wedge through a magenta contact screen (150 lines), and development of the exposed film then carried out at a temperature of 27C in Developer L, M or N, the formulae of which are shown below:  
 Developer L: Solution l:  
 wherein R R R and R which may be the same or different. each represents H, OH. CH;, or COOM, with M being a hydrogen atom, a water-soluble cation or lower alkyl group of not more than 4 carbon atoms.  
  2. The developer as claimed in claim 1 wherein said compound is from the group:  
 Sodium hydroxide 2 g. Potassium bromide 2 g. 0 O 0 0 0 Distilled water to make I67 ml 7 u 7| n a TOE; HO 4311 I i i ll O (i Before use. Solution 1 was added to 666 ml of water 0 /O and then Solution 11 added to make 1 liter of developer H0001 I CODE 00013 ready for use. i I U Developers M and N A ll To developer L was added Compound 8 or 9, respeco h I WCOOCzHs -oooc m The resulting photographic properties are shown in H0 i Table 4. 6 Y  
 Table 4 Developer Additive Amount Time of Dot quality Relative in g/l Development Speed In lTllI&#39;l.  
 Fresh Aged Development Development L None l% l0 I00 M Compound 8 3.0 1% 10 100 90 N Compound 9 3.0 1% I0 100 88 Table 4 ShOWS that the relative Speed of deVeIQPeYS 3. The developer as claimed in claim 1 where the dito which Compounds 8 and 9 have been added is re- 45 hydroxybenzene i hydroquinoney h| h d duced to a lesser degree than the developer free of qumone, b h d i ,i m d inone, compounds according to the invention. trihydroquinone, methylhydroquinone, 2,3-  
  Although the invention has been described in considdichlorohydroquinone or 2, 5 dimethy]hydr0quin0ne, erable detail with reference to certain preferred em- The develper as claimed in claim 1 where the f l. bodiments thereof, it will be understood that various lowing components are present in the following amoun-&#39; variations and modifications can be effected without ts per liter of developer: departing from thespirit and scope of the invention as compound(s): 0.1 30 g; described hereinabove and as defined in the appended dihydroxybenzene(s): 5 g; claims. sulfite ion buffer: 13 130 g;  
 What is claimed is: alkali to render developer alkaline.  
  An infectious deYeloper f photogrhphic materi 5. The developer as claimed in claim 1 where the 211s used I the g p arts F P l a hydro compound(s) is present in an amount of0.l 30 g. per qumone developing agent, an alkali, a sulfite and a sulliter f developer ft bff,th&#39; tff lft b&#39; l e u er 6 dmoun 0 Tee Su 1 e present emg 6. The developer as claimed in claim 4 where the deless than 5 g/l, and which contains at least one compound represented by the general formula veloper is at a pH of 9 or more.