US3411973A - Apparatus for etching a cellulosic printing plate - Google Patents

Apparatus for etching a cellulosic printing plate Download PDF

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Publication number
US3411973A
US3411973A US450971A US45097165A US3411973A US 3411973 A US3411973 A US 3411973A US 450971 A US450971 A US 450971A US 45097165 A US45097165 A US 45097165A US 3411973 A US3411973 A US 3411973A
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United States
Prior art keywords
belt
plate
cellulosic
etching
plush
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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
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US450971A
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English (en)
Inventor
Howard K Siler
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.)
Eastman Kodak Co
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Eastman Kodak Co
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Filing date
Publication date
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Priority to US450971A priority Critical patent/US3411973A/en
Priority to GB13169/66A priority patent/GB1092843A/en
Priority to BE679685D priority patent/BE679685A/xx
Priority to FR58083A priority patent/FR1476360A/fr
Priority to DE19661604514 priority patent/DE1604514B1/de
Application granted granted Critical
Publication of US3411973A publication Critical patent/US3411973A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C1/00—Forme preparation
    • B41C1/02—Engraving; Heads therefor
    • B41C1/025—Engraving; Heads therefor characterised by means for the liquid etching of substrates for the manufacturing of relief or intaglio printing forms, already provided with resist pattern

Definitions

  • FIG 3A l5 5 km HOWARD K. SILER I INVENTOR.
  • ABSTRACT OF THE DISCLOSURE A perforated plush belt for scrubbing the surface of a printing plate to etch the surface thereof wherein the perforations permit the removal of etchant and entrained cellulosic materials from the surface of the belt to prevent accumulation thereof in the pile.
  • This invention relates to halftone printing and particularly to an arrangement for solvent etching a relief halftone in a cellulosic sheet protected by a suitable resist stencil such as a photographically produced wash-01f gelatin image.
  • etching While the removal of material between the dots of a relief printing plate is normally referred to as etching, the actual operation is a softening of the cellulosic sheet by the solvent or etchant accompanied by a brushing to remove the softened areas. With hundred-line per inch halftones or finer, the hairs of the brush must be quite small to operate between the dots, even in the highlight regions where the dots are small, and particularly in the shadow regions where the dots merge and the cellulosic material to be removed leaves only a small hole.
  • the combined etchant and removed cellulosic material form what may be termed sludge.
  • a plush belt is disclosed for scrubbing the softened cellulosic sheet. However, it has been found that such a belt sometimes develops hard spots which tend to damage the plate. These hard spots are probably a result of'hardened sludge causing several fibers of the plush belt tostick together.
  • the primary object of the present invention i to provide a reliable etching arrangement having an improved belt for producing a halftone printing plate with excellent dot quality.
  • the light-sensitive gelatin layer on the plate to be etched may be of any of the forms used for the production of stencils. It is not necessary for the residual gelatin image or stencil to be clear. Accordingly, it is preferable to use one of the more eflicient types of recording systems, namely, that in which a silver salt is incorporated in the gelatin and in which a developer hardens the gelatin adjacent to the silver at the time the silver salt is reduced to silver.
  • a cellulosic plate is exposed, for example, to a halftone negative.
  • the exposed areas are developed with any of the standard hardening or tanning developers which reduce the silver salt to metallic silver and which harden the adjacent gelatin.
  • the unexposed gelatin areas of the plate are then removed by washing in warm water, just warm enough to remove the unhardened areas. All this is well known.
  • the environment of the present invention starts with an exposed, developed and washed-off plate consisting essentially of a cellulosic layer with a stencil thereon which is not soluble in the solvents to be used for softening the cellulosic layer.
  • the developed and washedoff, but not etched, plate is hereinafter referred to as a cellulosic plate with a developed stencil thereon.
  • the present invention works with such a cellulosic plate and stencil to provide an etched plate ready for inking and printing therefrom.
  • the machine using the invention includes a drivable drum having a cellulosic plate with developed stencil secured to its surface.
  • the plate on the drum engages, throughout its lowest segment, a plush belt continuously moistened with an etchant. Since the particlar etchants used are relatively ineffective without scrubbing, the belt is driven at a speed different from and in a plurality of directions relative to that of the exposed plate surface so that the pile of fibers of the belt continuously rubs against a major surface of the plate to apply etchant thereto and to remove softened portions of the exposed cellulosic material between resistant nodules or dots of the developed and tanned stencil. As the drum continues to rotate, moving the plate past the plush belt, the plate is wiped to remove excess etchant, dried by auxiliary heaters, and cooled prior to a next engagement of the etchant applied by the plush belt.
  • the plush belt is provided with a plurality of apertures spaced over its outer surface to allow etchant and cellulosic materials to escape therefrom in the form of sludge.
  • the plurality of escape routes for this sludge reduces the likelihood of collection of cellulosic material, as at the edge of the belt, to thereby form hard spots sometimes consisting of several bristles or fibers of plush pile secured together by 'undissolved cellulosic waste matter.
  • FIG. 1 is an elevation view partially in section of an etching arrangement using the present invention
  • FIG. 2 is a cross-sectional view taken along the line 2-2 of FIG. 1;
  • FIGS. 3A and B are magnified perspective views of a halftone plate unetched and etched respectively.
  • FIG. 4 is a detail view of the surface construction of the plush belt shown in FIGS. 1 and 2.
  • FIGS. 1 and 2 I have shown in FIGS. 1 and 2 a main drum 10 having a composite outer surface 12 and 13 for supporting a cellulosic plate 14 with a developed stencil thereon.
  • the stencil on the plate 14 consists of dots 15 (shown magnified in FIG. 3A) of hardened gelatin and the cellulosic layer is supported on a base material 16 such as metal.
  • the size of the dots 15 depends upon the relative halftone exposure of a particular area.
  • the plate takes the form shown in FIG. 3B.
  • one side of the drum 10 is exposed to the exterior of the machine to facilitate placing the plate 14 thereon and observation of the plate during etching.
  • the drum 10 with the plate 14 supported thereon is driven in a clockwise direction (FIG. 2) as indicated by an arrow 19 by a driving means such as a motor 17.
  • a driving means such as a motor 17.
  • a plush belt 18 supported by a pair of rollers 20 and 21.
  • the roller 21 is driven by a reversible motor 22 so that the surface of the plush belt 18 may be wiped in both directions across the lower surface of the cellulosic plate 14.
  • the rollers 20 and 21 and the plush belt 18 lie partially within a pan 24 having therein an etchant or solvent 26 somewhat like that used for thinning lacquer.
  • the etchant is replenished periodically by fresh etchant being applied directly to the belt 18 from a distributor pipe 27.
  • the plush belt is provided with a plurality of such holes or apertures 28 in a stag gered or diamond pattern, which holes allow escape of sludge as indicated by arrows 29.
  • the sludge dropping through the holes 28 falls onto a run-off pan 30. Holes of one-fourth inch diameter work satisfactorily.
  • the surface of the belt 18 travels at about 120 feet per minute and is reversed about 30 times per minute.
  • a plush roller 32 As the successive portions of the plate 14 leave the region of the plush belt 18, they are wiped by a plush roller 32 to remove susbtantially all of the sludge remaining thereon.
  • the plush roller 32 As it is rotated in a clockwise direction by a driving motor 33, the plush roller 32 is wiped clean by a rigid wiper 34. Used etchant and cellulosic matter (sludge) are removed from the plate 14 by the roller 32 and collected on the wiper 34, flows into a trough 36 and from there to a waste material collection receptacle.
  • this wiped-off sludge is of a thin enough consistency to flow through a waste pipe 37 without serious danger of clogging it.
  • the particular drying apparatus shown in FIG. 2 is a combination hot air and radiant heater system.
  • the hot air portion utilizes a plurality of parallel pipes 40 having inwardly opening apertures 41 which direct air, heated to temperatures of the order of 200 F., against the surfaces of the plate 14.
  • Several radiant heaters 42 may be added. These heaters 42 must be operated at temperatures below the ignition temperatures, such as 700 F., of the various chemicals being used.
  • exhaust means substantially surrounding the pipes 40 and the heaters 42 in the form of an exhaust hood 43 with a fan 44 (FIG. 1) for removing the heatedair containing the volatile solvents.
  • this contaminated air is removed both from the region of the subject etching arrangement and from the building housing the equipment.
  • the inlet to the hot air pipes 40 comprises a filter 52, a fan 53, a heater 54 and duct means 55 which conveys the heated air to both ends of the hood 43 wherein plenum chamber distributors 56 convey air to both of the ends of each of the pipes 40.
  • the capacity of the fan 44 is made larger than that of the fan 53.
  • the plate 14 is cooled to near room temperature prior to the next cycle.
  • Auxiliary cooling means such as cool air impingment is obtained from a distributor pipe 58 to assure suitable cooling.
  • additional or no cooling means may be employed.
  • a lateral drive of the plush belt 18 is preferably accomplished by an eccentric drive motor 60- connected by a lever 62 to a drive arm 63 of a support frame 64 for the rollers 20 and 21.
  • a speed of 60 r.p.m. is suitable for the eccentric drive motor 60 when the length of its stroke is of the order of one inch.
  • the platform 66 supporting the pan support rollers 67 must be at least this large.
  • the motor 22 will be most effective if it is mounted on the support frame 64 or provided with a universal drive linkage 68, as shown in FIG. 1.
  • An additional control feature enhances the attaining of quality plates, and that is regulation of the pressure between the plush belt 18 and the drum 10. Both the total pressure and the distributed pressure are important.
  • the total pressure is regulated by upward force developed by the support platforms 66. Pneumatic means such as air cylinders 70 will provide this force.
  • the distributed pressure is a function of the sag of the plush belt 18 between the rollers 20 and 21.
  • the apparatus including a rotatable drum for supporting the plate with the stencil surface thereof engaged by a plush belt which scrubs the surface, the plush belt having a flexible backing faced with a pile on the scrubbing surface thereof which is wet during scrubbing of the plate with an etchant to soften only the exposed areas of the cellulosic layer, the belt being driven at surface velocities different from that of the plate on the drum and in a plurality of directions relative to the surface of the plate so that the softened portions are scrubbed away, the improvement wherein:
  • the plush belt is provided at locations remote from the edges thereof with a plurality of holes through the flexible backing to remove etchant and entrained cellulosic materials from the scrubbing surface of said belt to reduce the accumulation thereof in said pile.
  • holes in said belt are at least about one-fourth inch diameter and are spaced about six holes per square foot of belt area.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Printing Plates And Materials Therefor (AREA)
US450971A 1965-04-26 1965-04-26 Apparatus for etching a cellulosic printing plate Expired - Lifetime US3411973A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US450971A US3411973A (en) 1965-04-26 1965-04-26 Apparatus for etching a cellulosic printing plate
GB13169/66A GB1092843A (en) 1965-04-26 1966-03-24 Improvements in or relating to etching apparatus
BE679685D BE679685A (enrdf_load_stackoverflow) 1965-04-26 1966-04-18
FR58083A FR1476360A (fr) 1965-04-26 1966-04-19 Appareil pour la morsure en continu de planches d'impression
DE19661604514 DE1604514B1 (de) 1965-04-26 1966-04-22 Vorrichtung zum aetzen von druckplatten aus zellulose die eine photographisch entwickelte schicht aufweisen

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US450971A US3411973A (en) 1965-04-26 1965-04-26 Apparatus for etching a cellulosic printing plate

Publications (1)

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US3411973A true US3411973A (en) 1968-11-19

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US450971A Expired - Lifetime US3411973A (en) 1965-04-26 1965-04-26 Apparatus for etching a cellulosic printing plate

Country Status (4)

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US (1) US3411973A (enrdf_load_stackoverflow)
BE (1) BE679685A (enrdf_load_stackoverflow)
DE (1) DE1604514B1 (enrdf_load_stackoverflow)
GB (1) GB1092843A (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4426250A (en) 1981-01-02 1984-01-17 Brailsford Michael I D Stripper system for surfaces
US4637856A (en) * 1985-12-12 1987-01-20 Dixon Industries Corporation Apparatus and process for etching fluoroplastics
US5167747A (en) * 1989-02-15 1992-12-01 Kadija Igor V Apparatus for manufacturing interconnects with fine lines and fine spacing
US5425840A (en) * 1992-10-07 1995-06-20 Photomeca Automated process for making flexible plates from a sheet introduced sensitive side facing upwards and device for implementing the process
US5507876A (en) * 1993-04-29 1996-04-16 Wandres; Claus G. Process for removal of particles adhering to surfaces by use of a wiping element
US5723019A (en) * 1994-07-15 1998-03-03 Ontrak Systems, Incorporated Drip chemical delivery method and apparatus

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3266196A (en) * 1962-10-22 1966-08-16 Sperry Rand Corp Tape cleaning means
US3271226A (en) * 1963-08-09 1966-09-06 Eastman Kodak Co Etching apparatus for making a cellulosic printing plate

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3266196A (en) * 1962-10-22 1966-08-16 Sperry Rand Corp Tape cleaning means
US3271226A (en) * 1963-08-09 1966-09-06 Eastman Kodak Co Etching apparatus for making a cellulosic printing plate

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4426250A (en) 1981-01-02 1984-01-17 Brailsford Michael I D Stripper system for surfaces
US4637856A (en) * 1985-12-12 1987-01-20 Dixon Industries Corporation Apparatus and process for etching fluoroplastics
US5167747A (en) * 1989-02-15 1992-12-01 Kadija Igor V Apparatus for manufacturing interconnects with fine lines and fine spacing
US5425840A (en) * 1992-10-07 1995-06-20 Photomeca Automated process for making flexible plates from a sheet introduced sensitive side facing upwards and device for implementing the process
US5507876A (en) * 1993-04-29 1996-04-16 Wandres; Claus G. Process for removal of particles adhering to surfaces by use of a wiping element
US5723019A (en) * 1994-07-15 1998-03-03 Ontrak Systems, Incorporated Drip chemical delivery method and apparatus
US5853522A (en) * 1994-07-15 1998-12-29 Ontrak Systems, Incorporated Drip chemical delivery apparatus

Also Published As

Publication number Publication date
GB1092843A (en) 1967-11-29
BE679685A (enrdf_load_stackoverflow) 1966-10-03
DE1604514B1 (de) 1971-08-12

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