US2969014A - Photochemical stencil and method for manufacture - Google Patents

Photochemical stencil and method for manufacture Download PDF

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Publication number
US2969014A
US2969014A US716099A US71609958A US2969014A US 2969014 A US2969014 A US 2969014A US 716099 A US716099 A US 716099A US 71609958 A US71609958 A US 71609958A US 2969014 A US2969014 A US 2969014A
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US
United States
Prior art keywords
stencil
coating
negative
photochemical
silver halide
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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
Application number
US716099A
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English (en)
Inventor
Donald E Hanson
Mary K Ormsbee
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AB Dick Co
Original Assignee
AB Dick Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to NL103914D priority Critical patent/NL103914C/xx
Priority to BE575893D priority patent/BE575893A/xx
Priority to NL236208D priority patent/NL236208A/xx
Application filed by AB Dick Co filed Critical AB Dick Co
Priority to US716099A priority patent/US2969014A/en
Priority to GB5111/59A priority patent/GB857632A/en
Priority to FR787063A priority patent/FR1221970A/fr
Priority to DED30034A priority patent/DE1184215B/de
Application granted granted Critical
Publication of US2969014A publication Critical patent/US2969014A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/12—Production of screen printing forms or similar printing forms, e.g. stencils

Definitions

  • This invention relates to a multiple copy process and it relates more particularly to a new and improved photochemical stencil and to the method for the preparation of a stencilized master therefrom.
  • the stencil duplicating process for the preparation of multiple copies makes use of a stencil sheet formed of a stencil base tissue which is provided with a continuous coating of an ink impervious material which prevents the passage of ink but which is formu- "lated to permit displacement of the coating responsive without blocking the passage of ink from the plate cylinder to the copy sheets brought into surface contact therewith.
  • the described normal method for the preparation of the imaged stencil is not applicable to the preparation of 'a stencil either directly or indirectly from an original.
  • a stencil sheet embodying a coating containing a light-sensitive material which operates upon exposure to render the coating insoluble so that the coating can be dissolved out from the unexposed areas to provide the stencil openings.
  • a stencil sheet which can be imaged for reproduction from an original; which can be prepared at a common source of supply in a simple and economical *manner; which can be fabricated of low cost and readily available materials; which avoids the necessity for sensi- -tization at the station of use, and which can therefore be presensitized long in advance of the use of the stencil at a common source for supply; which has good shelf life and stability; which can be imaged in a simple and efficient manner without the use of extensive equipment and labor and without an excessive number of operations, and which can be used as a conventional stencil on a stencil duplicating machine to produce a large number of copies of good quality.
  • Fig. 1 is a perspective view partially in section of a stencil sheet embodying the features of this invention
  • Fig. 2 is a perspective view similar to that of Fig. 1 showing a modification in the construction of a stencil sheet embodying the features of this invention
  • Fig. 3 is a perspective view similar to that of Fig. 1 illustrating the construction of the stencil sheet following exposure
  • Fig. 4 is a perspective view similar to that of Fig. 1 showing the constructionof the stencilized stencil sheet.
  • fogging agents use is made of a substance capable of promoting the reduction of silver halides without requiring the action of light, such for example as colloidal silver, colloidal forms of sulphur, silver sulfides, hypophosphites, stannous chloride, and organic compounds which are capable of splitting off sulphur in the form of bivalent ions, as represented by thiosinamine and thiocyanates.
  • Such fogging agents are preferably embodied in the copy sheet during the manufacture thereof or they can otherwise be incorporated by a subsequent coating or impregnation.
  • the concepts of this invention are embodied in the manufacture of a stencil which is capable of development by a diffusion transfer technique to provide a one step exposure process for imaging the stencil directly from an original.
  • the stencil is fabricated in accordance with the practice of this invention of a conventional base tissue 10, such as is formed of Kozu fibers and the like,
  • nucleating or reactive agent which operates to form a more dis P FSGd image in the coating thereby to achieve better and more complete degradation of the gelatin to enhance removal from the imaged areas of the coating.
  • materials of the type previously described as being employed in the single copy process of Rott and best results are secured in the combination which makes use of a sulfide in the, form of ammonium or metal sulfide and preferably an alkali metal sulfide such as sodium or potassium sulfide and a soluble silver salt such as silver nitrate.
  • the combination of materials can be used in the coating in combination with other nucleating agents as listed above, such as ammonium thiosulfate and the like.
  • nucleating materials are present in the gelatin coating in .an amount greater than 0.05 percent by weight of the coating. It is preferred to make use of the nucleating agent in a concentration in the coating ranging from 0.1-0.5 percent by Weight of the coating. The upper limit of concentration is not critical but little additional benefit is derived from the portions of the nucleating agent which are present in an amount greater than 2 percent by weight of the coating and use in amounts greater than described leads to difficulties in formulation and in the characteristics of the coating that is formed on the stencil base tissue.
  • the complex silver salts transfer by diffusion from the unexposed portions of the negative to the gelatin coating, the salts are reacted with the nuclcating agents in the coating to produce a dispersed silver image.
  • The, subsequent etching reaction leads to the degradation of the gelatin in the imaged areas 14 of the coating which reduces the gelatin to a condition which enables it to be removed by the treating or etching solution which has no effect on the unreacted, hardened portions of the gelatin emulsion or coating in the non-imaged areas. This leaves the hardened gelatin in the non-imaged areas while the gelatin coating in the imaged areas is removed to provide stencil openings 16 through which the ink may pass.
  • gelatin in an emulsified form in the manufacture of the coating 12 on the stencil base sheet 10
  • gelatin in other hardenable forms can be used. Though not exactly equivalent,
  • proteinaceous colloids such as the alginates, caseins,
  • albumens and the like may be used as the polymeric material forming the coating and containing the nucleating substances leading to the degradation of the colloid n t s e wnta n s ma ed ar as e o n up re t on with. he e chin i reatin s n- T e tol wins i i us rate t e pr c i e f h sh icn in. he fabricat on o ne ad mp ov ar sensitized stencil sheets and in the use thereof to image the stencil from an original:
  • EXAMPLE 1 Stencil sheet manufacture The materials are formulated into a hot melt at a temperature of about F. and applied to form a coating onto a high wet strength stencil base tissue having about 5 pounds basis weight.
  • the coating is applied in amounts to provide a coating weight of 3 grams per square meter and then the coated base tissue is sheeted into stencil sheets.
  • the coating may be achieved by conventional roller coating processes or other conventional coating processes represented by the dip squeeze process and the like.
  • Coating weights other than 3 grams per square meter may be employed including weights as low as 2 grams per square meter to as high as 10 grams per square meter but it is preferred to keep the coating weight on the low side so as to facilitate the removal of the coating in the imaged areas of the stencil sheet during the subsequent etch treatment.
  • the exposed photographic negative is developed in a solution containing the normal developing components employed in the photographic art plus a material which is capable of functioning as a solvent for the silver halide or the silver halide complex that is formed.
  • a typical mono-bath developer including a developer and a fixer such as are ordinarily employed in the photographic practice, as represented by a solution formulated of the following:
  • the exposed negative and the stencil base tissue will be run together into a bath of the developing solution and then will be brought into surface contact with each other between squeeze rolls as the sheets issue from the developing solution.
  • the soluble silver complex formed of the silver halide present in the unexposed portions of the negative coating transfers by diffusion to the corresponding areas of the stencil coating 12. Transfer may be instantaneous upon contact but it is preferred to provide means for maintaining contact for a greater length of time ranging from a few seconds up to as much as 2 minutes.
  • the silver nitrate and sodium sulfide together or in combination with the ammonium thiosulfate in the stencil coating 12 promote the reduction of the silver halide complex that is transferred to the stencil coating to produce a silver image.
  • a degradation of the gelatin in the imaged areas to reduce the gelatin to a form capable of being removed from the stencil base sheet is brought about by treatment with an acid etch solution as represented by the following composition published by Eastman Kodak Company under the designation EB-2.
  • etch solution 750 cc. water, 120 grams copper sulfate, 150 grams citric acid and 7.5 grams potassium bromide are dissolved in water in amounts to make up 1 liter.
  • the two compositions are mixed to form a composite etch solution through which the processed stencil sheet is passed.
  • the etch solution operates to degrade (probably by reaction with the silver and gelatin in the imaged areas) and remove the gelatin in the imaged areas to provide stencil openings 16 while it has practically no effect upon the hardened gelatin in the non-imaged areas so that the latter will remain as a coating on the stencil base tissue to prevent the passage of ink.
  • the processed stencil base tissue is treated by passage through the etch solution subsequent to its separation from the exposed negative.
  • etch compositions can be employed containing similar copper salts, bromides and acids efiective to remove the gelatin in the degraded areas.
  • the formed stencil can be mounted on a conventional ink cylinder of a stencil duplicating machine to produce multiple copies. It will be apparent that the concept described can also be employed as a photochemical means for the preparation of stencils used in the silk screen processes for printing and the like.
  • the concepts herein described are capable of being adapted to a one sheet process wherein the negative coating is embodied as a component of the stencil sheet.
  • the colloid coating containing the silver halide of the conventional negative is fabricated as an overcoating on the coating 12 applied to the stencil base tissue 10.
  • EXAMPLE 3 To the point where the stencil base sheet 10 is formed with the coating 12 of a hardened ink impervious colloid, the process corresponds to that of Example 1.
  • the negative coating 20 is applied as a separate coating onto the 6 surfaceof the coating 12.
  • the negative coating is of a conventional formulation represented by the following:
  • mixtures A and B are combined and then mixture C is added and the composite is digested for 16 minutes at about F.
  • the final materials Prior to application of the coating composition onto the previously applied coating 12, the final materials are added including 0.2 gram citric acid, 12.0 ml. ethyl alcohol and 2.8 ml. of water.
  • the final composition is mixed and applied by conventional coating means at a temperature of about 120 F. and in a coating weight of about 10-20 grams per square meter.
  • Exposure with the original operates in the same way as a conventional photographic negative to produce a latent image in the silver halide coating 20 without effect on the underlying colloid coating containing the nucleating agents.
  • Transfer of the soluble complex silver salts from the non-exposed portions of the negative coating 20 to the underlying stencil coating 12 during development by the fixing and developing bath containing a solvent for the silver halide occurs by diffusion from the one coating to the other during the development by the fixing and developing bath containing a solvent for the silver halide.
  • the negative coating and the imaged portions of the colloid in the stencil coating 12 are all removed by the etch solution to produce the imaged stencil.
  • the described stencilization of a stencil by photographic technique from an original embodies the simplicity char acteristic of the diffusion transfer process to provide a means for stencilization capable of use with a wide range of originals.
  • the concepts of this invention permit the preparation of a stencil master from many types of originals by reflex, print-through contact or projection printing methods.
  • the prepared stencil is prehardened and insensitive to light so that it can be prepared in quantity for storage and shipment to distant stations of use with readily available presensitized negative papers.
  • the described concept further provides a simple, rapid and economical means for producing an imaged stencil master by a photographic technique.
  • a photochemical stencil comprising a stencil base tissue and an ink impervious coating on the stencil base tissue formed of a hardened proteinaceous colloid containing a nucleating agent for the release of silver upon reaction with a silver halide complex.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Printing Plates And Materials Therefor (AREA)
  • Silver Salt Photography Or Processing Solution Therefor (AREA)
  • Manufacture Or Reproduction Of Printing Formes (AREA)
  • Photosensitive Polymer And Photoresist Processing (AREA)
US716099A 1958-02-19 1958-02-19 Photochemical stencil and method for manufacture Expired - Lifetime US2969014A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
NL103914D NL103914C (en(2012)) 1958-02-19
BE575893D BE575893A (en(2012)) 1958-02-19
NL236208D NL236208A (en(2012)) 1958-02-19
US716099A US2969014A (en) 1958-02-19 1958-02-19 Photochemical stencil and method for manufacture
GB5111/59A GB857632A (en) 1958-02-19 1959-02-13 Improvements in or relating to photochemical stencils
FR787063A FR1221970A (fr) 1958-02-19 1959-02-18 Stencil photochimique et son procédé de fabrication
DED30034A DE1184215B (de) 1958-02-19 1959-02-19 Verfahren zur Herstellung von Vervielfaeltigungsschablonen auf photochemischem Wege

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US716099A US2969014A (en) 1958-02-19 1958-02-19 Photochemical stencil and method for manufacture

Publications (1)

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US2969014A true US2969014A (en) 1961-01-24

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US716099A Expired - Lifetime US2969014A (en) 1958-02-19 1958-02-19 Photochemical stencil and method for manufacture

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US (1) US2969014A (en(2012))
BE (1) BE575893A (en(2012))
DE (1) DE1184215B (en(2012))
FR (1) FR1221970A (en(2012))
GB (1) GB857632A (en(2012))
NL (2) NL236208A (en(2012))

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3131628A (en) * 1961-10-10 1964-05-05 Anken Chemical & Film Corp Diffusion transfer thermographic stencil and process
US3181458A (en) * 1961-02-16 1965-05-04 Anken Chemical & Film Corp Transfer process for producing stencils
US3260600A (en) * 1960-10-20 1966-07-12 Gevaert Photo Prod Nv Photographic image-receiving material
US3547641A (en) * 1966-06-20 1970-12-15 Du Pont Planographic offset printing masters
US5816269A (en) * 1997-11-24 1998-10-06 Mohammed; Khadija Tatoo stencil mechanism

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1294267B (de) * 1963-05-29 1969-04-30 Bundesrepublik Deutschland D D Treibladung fuer rueckstossfrei abfeuerbare Geschosse
US3383210A (en) * 1963-10-28 1968-05-14 Gevaert Photo Prod Nv Photochemical stencils

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1494667A (en) * 1921-09-06 1924-05-20 John D Coe Photographic stencil and method for making same
US1588574A (en) * 1920-12-15 1926-06-15 Gestetner Ltd Duplicating
US2352014A (en) * 1941-07-21 1944-06-20 Rott Andre Photomechanical printing process and printing material for carrying out the same
US2665986A (en) * 1939-11-02 1954-01-12 Gevaert Photo Prod Nv Process of producing colored reversal images

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1588574A (en) * 1920-12-15 1926-06-15 Gestetner Ltd Duplicating
US1494667A (en) * 1921-09-06 1924-05-20 John D Coe Photographic stencil and method for making same
US2665986A (en) * 1939-11-02 1954-01-12 Gevaert Photo Prod Nv Process of producing colored reversal images
US2352014A (en) * 1941-07-21 1944-06-20 Rott Andre Photomechanical printing process and printing material for carrying out the same

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3260600A (en) * 1960-10-20 1966-07-12 Gevaert Photo Prod Nv Photographic image-receiving material
US3181458A (en) * 1961-02-16 1965-05-04 Anken Chemical & Film Corp Transfer process for producing stencils
US3131628A (en) * 1961-10-10 1964-05-05 Anken Chemical & Film Corp Diffusion transfer thermographic stencil and process
US3547641A (en) * 1966-06-20 1970-12-15 Du Pont Planographic offset printing masters
US5816269A (en) * 1997-11-24 1998-10-06 Mohammed; Khadija Tatoo stencil mechanism

Also Published As

Publication number Publication date
FR1221970A (fr) 1960-06-07
DE1184215B (de) 1964-12-23
NL103914C (en(2012))
BE575893A (en(2012))
GB857632A (en) 1961-01-04
NL236208A (en(2012))

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