Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F5/00—Screening processes; Screens therefor
  • G03F5/20—Screening processes; Screens therefor using screens for gravure printing

Definitions

• the metallic support utilised for theprinting form '(plateQcyIinderorthe like) is coated with l copied at the same' time upon the light sensitive .layer of the printing form.
• the treatment with an etching solution is performed in accordance to the present invention.
• etching solutions which, besides the usual mordant, like ferric chloride, contain an acid of such a kind, as for instance lactic acid or the like, which attacks or penetrates and swells the not hardened colloid layer but does not corrode or attack the metal of the plate or the like.
• an acid of such a kind as for instance lactic acid or the like
• the half tone image and the screen are transferred directly to a light sensitive layer which has previously been arranged on the metallic support.
• a light sensitive layer which has previously been arranged on the metallic support.
• the least hardened part lies on the underside, i. e. in contact with the metallic support.
• the time, for copying thescreen should be longer by about one quarter of the time required for copying the half tone image, say for instance 8 minutes for. the screen against 6 minutes for the half tone image. -Now, all other things being equal, it has proved .suitable, when using the process of the present invention, to expose for the copying of the screen about thrice as long as for the copying of the half to'neimage, say for instance about 18 minutes against 6 minutes.
• the process according to the present invention may be executed in different ways andmanners.
• the layer of the light sensitive colloid may consist of a chromatised glue. soluble in warm water, like the chromatised so-called Beka. photoengraving glue (as manufactured by Messrs. Dr. Bekk 8: Kaulen Chemische Fabrik G. m. b. H., of Loevenich, .near Cologne), or chromatised gum arable. After the screen and the diapositive or the like are copied on this .only to a relatively low degree.
• the etching solution in this case is composed in such a way, that is to say it shall suitably have such a viscosity, that the copying layer, even if not exposed to the light, would not be influenced by the ferric chloride solution as such, but that the added weak acid attacks and penetrates those parts of the colloid layer, which are not hardened at all or
• an etching solution adapted for this purpose may be taken a ferric chloride solution of 48-50 B with an addition of 3-5% lactic acid.
• a treatment with an etching bath of the usual kind for instance a ferric.
• a layer of chromatise'd gelatine may be employed which is produced by means of the unchanged gelatine as it is on sale and which quickly sets and only swells in warm water without dissolving.
• the image after having been; transferred to the chromatised layer in an adequate manner and after the latter having been screened by exposure may first be developed 'in water. The temperature of the developing water, however, then ought to be such, that the gelatine is not dissolved even at the spots not exposed to the light and consequently not hardened, but.
• the mordant will penetrate morequickly or more slowly through the gelatine layer to the metal and will efiect herethe correspondingly graduated etching. .
• the gelatine layer may be removed in a corresponding manner as in the procedure described before.
• the degreeof hardening and of swelling dependent thereupon may be, more 3 or less of the filler will be washed out of a certain partof thegelatine layer. The latter, however, will be more readily penetrated by the etching means at the spots more freed from the filler than at those places, which retain still more or all of it. Thus the gradation of the tone in the etched image will be furthermore influenced favourably.
• pigments may be used, I. i. the red pigment of Messrs. H. Schmincke 8; Co., of Dusseldorf. ,
• the use of such pigmentsyet offers theparticular advantage that at the same time a coloration of the gelatine layer is, caused and therefore the inspection of the developed gelatine image is facilitated, as during the development more or less of thepigment is dissolved out of, the parts of the layer hardened not or ,less.
• a cleaned copper plate may be coated for this purpose in the whirler with a copying mixture composed of 1000 mm of water, 120 gr. of edible gelatine, 100 com. of Beka photoengraving glue,
• the plate or the like is exposed under the diapositiveor the like and under the screen during the required time, the development is carried out.
• the plate is suitably first put into warm water where it is left, for instance,
• the tanning agent may consist of 1000 ccm. of water, 20 to 30 gr. of water-soluble aniline dye, like methyl violet, and 40 to 50 gr. of alum. After some minutes the plate is taken out of this bath, and the development then is finished in warm water.
• the used water soluble aniline dye also serves the purpose to facilitate the examination of the developed image or of the degree of development reached, since during the final development in warm water this'dye is washed out or away from those places where the unhardened swollen or relatively little It is selfexplanatory that the dyeing with aniline dye, if desired, may be employed also where no filler like a pigment was added to the colloid solution.
• the tanning agent f. i.
• alum added to the middle bath confers to the layer the necessary stability during etching and contributes furthermore to promotethe gradation of the latter according to the tone values of the image or picture.
• any othersuitable tanning agent maybe used, f. i. formaline or the like.
• the tanning means in the same bath as with the dyeing solution, but they may be effected independently from one another. Also, the treatment with the tanning agent or with the dyeing solution, or with both agents may be omitted.
• the tanning may be combined with the etching by adding the tanperformed in the otherwise usual way, for instance with ferric chloride solution of varying composition and concentration.
• the etching may be performed under full daylight, in contrast to the first example of execution where the undeveloped image was to be etched.
• the varnish is removed and then the remaining copying layer, if desired by means of water and emery powder or the like.
• the process according to the present invention is suited in first line for the manufacture of planographlc intaglio printing forms, but'it may also bev employed for the'manufacture of rotary intaglio printing forms.
• metal for the plates or the like copper is the most important, but in certain cases other metals, such' as brass, zinc or aluminum may also-be employed.
• A. process for the photomechanical manufacture of printing forms for intaglio printing by means of a doctor which comprises covering a metallic body used as the basis for the printing form with a light sensitive chromatized colloid layer, exposing the same twice, under a diapositive of a continuous unscreened half-tone image and under a photogravuro screen in any succession, the one after the other, and then treating said metallic body coyered with the undeveloped, twice exposed colloid layer with a swelling means and. an etching means.
• a process for the photomechanical manufacture of printing forms for intaglio printing by means of a doctor which comprises covering a metallic body used as the basis for the printing form 'with a light sensitive chromatized colloid layer, exposing the same tWice under a diapositive of a continuous half-tone image and under a photogravure screen in any succession, the one photogravure screen being" made for a longer period than that independently made for copying the continuous halt-tone image and for such a time, that those parts of the sensitive layer the,
• I 3. A process for the photomechanicalmanuiac-ture of printing-forms forintaglioprinting by meansof a, doctor which comprises covering" a metallic body used as the basis for the printing form with a layer of gelatine of .thetrade of such a kind which only will swell on being treated with warm. water without dissolving and which is rendered light sensitive by chromatizing exposing said sensitive layer twice, under a diapositive of a'continuous'halI-toneimage and under a photogravure screen-in any succession, the one 1 after the other, then treating said twice exposed gelatine layertwlth water ot such a temperature,
• a process for the photomechanicalmanufacture of printing forms forintaglio printing by means ot a doctor which comprises covering a metallic-body used as the basis forthe printing form with alight sensitivechrornatized colloid layer, exposing the same twice, under a diaposi- 1 tive of a continuous half-tone'imageand under a photogravure screen inanysuccession, the one after theother, and 'then tre'ating' said metallic body with the undeveloped, twice exposed colloid layer simultaneously with swelling-etching means, said means consisting. of a mixture of an etching salt and a weak organic acid, said organic'acid,
• a process for the 'phot'omechanical manufacture of printingforms for intaglio printing by means of adoctor which comprises covering a metallic body used as'the basis for the printing form with a light sensitive chromatized colloid layer, exposing the sametwice, under a diapositive of a continuous halt-tone image and under 1 aphotogravure screen in any succession, the one after the other, and then treating said metallic body with the undeveloped, twice exposed colloid layer simultaneously with swelling-etching means, saidmeans consisting of a mixture of ferric chloride and lactic acid.
• a process for the photomechanical manufacture of printing forms ,ior intaglio' printing by means of a doctor which comprises covering a metallic body used as the basis for the printing i'orm with a layer of gelatine of the trade of such a kind which only will swell on being treated with warm water without dissolving and which is rendered 'light sensitive by.
• a process for the photomechanical manuiacture ofprinting forms for intaglio printing by means of a doctor which comprises covering a metallic body used as the basis for the printing form with a layer of gelatine of the trade of -such a kind which only will swell on being treated with warm water without, dissolving and which is rendered light sensitive by chromatizing, exposing said sensitive layer twice, under a diaposi- "tive of a continuous half-tone image and under a photogravure screen in any succession, the one after the other, then treating said twice exposed gelatine layer with water of such 'a temperature, that ,the gelatine is not dissolved even at the qunexposed spots but is only caused to swell at saidspots, dissolved dyes, being added during this treatmenhthen removing said dyes again from the unexposed spots of said gelatine layer by an after-treatment with water, and thereafter bringing an etching means on said treated gelatine layer, said etching means penetrating the previously swelle
• a process for the photomechanical'manu facture of printing forms for intaglio printing by means of a doctor which comprises covering a metallic body used as the basis for the printing form with a layer of gelatine of the trade of such a kind which only will swell on being treated with warm water without dissolving and which is rendered light sensitive by chromatizing, ex-
• gelatine is not dissolved even at the unexposed spots but is only caused to swell at said spots, dissolved dyes and a tanning agent being added during this treatment, then removing said dyes again from the unexposedspots of said gelatine layer by-an' after-treatment with water, and thereafter bringing an etching means on said treated gelatine layer, said etching means penetrating the previously swelled parts ofsaid gelatine layer and etching theparts'of said metallic body beneath said swelled gelatine parts.
• Aprocess for the photomechanical manui'acture of printing forms for intaglio printing by means of a doctor which comprises covering a metallic body used as the basis for the printing form with a layer of gelatine of the trade of such a kind which only will swell on being treated with warm water without dissolving and which is rendered light-sensitive by chromatizing, ex-

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Photosensitive Polymer And Photoresist Processing (AREA)
• Manufacture Or Reproduction Of Printing Formes (AREA)
• Printing Plates And Materials Therefor (AREA)
• Printing Methods (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=48614223

Family Applications (1)

Country Status (6)

Cited By (4)

Families Citing this family (1)

• 1935
  • 1935-04-02 DE DEB169309D patent/DE746727C/de not_active Expired
• 1936
  • 1936-02-12 GB GB4289/36A patent/GB458968A/en not_active Expired
  • 1936-02-22 NL NL76694A patent/NL48129C/xx active
  • 1936-03-04 US US67068A patent/US2159588A/en not_active Expired - Lifetime
  • 1936-03-05 FR FR804072D patent/FR804072A/fr not_active Expired
  • 1936-03-23 BE BE414579D patent/BE414579A/xx unknown
• 1937
  • 1937-05-03 FR FR48536D patent/FR48536E/fr not_active Expired
  • 1937-05-04 GB GB12758/37A patent/GB482230A/en not_active Expired

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