US2348943A - Planographic printing plate - Google Patents

Planographic printing plate Download PDF

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Publication number
US2348943A
US2348943A US484833A US48483343A US2348943A US 2348943 A US2348943 A US 2348943A US 484833 A US484833 A US 484833A US 48483343 A US48483343 A US 48483343A US 2348943 A US2348943 A US 2348943A
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US
United States
Prior art keywords
plate
printing
cellulose
parchmentized
sheets
Prior art date
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
US484833A
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English (en)
Inventor
William B Wescott
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
Multigraphics Inc
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 BE472881D priority Critical patent/BE472881A/xx
Priority to NL132918D priority patent/NL132918B/xx
Application filed by Multigraphics Inc filed Critical Multigraphics Inc
Priority to US484833A priority patent/US2348943A/en
Priority to GB434/44A priority patent/GB570035A/en
Priority to CH245700D priority patent/CH245700A/fr
Application granted granted Critical
Publication of US2348943A publication Critical patent/US2348943A/en
Priority to FR916254D priority patent/FR916254A/fr
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
    • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
    • B41N1/00—Printing plates or foils; Materials therefor
    • B41N1/12—Printing plates or foils; Materials therefor non-metallic other than stone, e.g. printing plates or foils comprising inorganic materials in an organic matrix
    • B41N1/14—Lithographic printing foils

Definitions

  • This invention relates to planographic printing and more particularly to a parchmentized cellulose planographic printing plate, and this application is a continuation-in-part of my copending application Serial No. 471,673, filed J anuary 8, 1943.
  • My prior patents, Nos. 2,134,165 and 2,205,998 may be referred to'as showing the state of this art.
  • Parchmentized cellulose planographic printing plates offer numerous advantages over the older planographic' printing plates of metal by reason of their flexibility and ease of handling in a typewriter, rendering them particularly adapted to ofice use in connection with cylinder oflset reproducing machines.
  • the use of parchmentized cellulose printing plates though extensive, has been limited in certain respects. Their use could have been greatly enlarged were it not for two conditions that have not heretofore been overcome, namely, (1) the very short useful life of unbacked parchmentized cellulose printing plates, and (2) the difliculties, expense, and complications encountered in making and handling the prior parchmentized cellulose'printing plates having backing layers.
  • Contamination of the printing surface may also occur as a result of pressure contact of the printing face of one sheet with the backing of another,
  • Objects of the present invention are to avoid the above difficulties and disadvantages, to provide a parchmentized cellulose printing element that is cheaper than the previous backed elements, and with which it is easy to avoid contamination in manufacture and handling.
  • the invention involves the discovery that by taking twosheets of cellulose water leaf, each in the process of being acted on by the acid in parchmentizing, at least one being adapted to serve as a planographic printing surface upon washing and drying, and then in a manner known in the making of laminated parchment, A laminating and cohering these together while under the influence of the acid and washing the acid therefrom, and drying, there can be made,
  • Fig. 1 is a perspective view of a printing plate made in accordance with the present invention.
  • Fig. 2 is an enlarged fragmentary edge view of the printing-plate of Fig. 1;
  • Fig. 3 is a schematic view indicating the principal steps in manufacturing the material of the printing plates of the present invention.
  • the material of the printing plate consists entirely of cellulose, consisting in part of the fibrous form of cellulose and in part of the amyloid non-fibrous form of cellulous resulting from the parchmentizing process.
  • parchmentized cellulose suitable for use as a planographic printing plate are: that it readily receives and retains the ink-receptive image-forming material (of which numerous examples are known to ducing the material for this planographic printing plate is as follows: a
  • Two webs 20 and 2! of unsized paper or waterleaf made from bleached sulphite stock. free from any of the undesirable added components or contaminants as explained above, are simultaneously subjected to a conventional parchmentizing treatment in a sulphuric acid bath 2!.
  • a sulphuric acid bath 2! Upon emerging from the bath and while their surfaces are still in the gelatinous state induced by the acid and still wet thereby, the two webs II and II are led into contact face to face and passed between a pair of press rolls 2! and 2
  • the acid and water are re-- moved by passing the composite web through any suitable washing apparatus 21 and drying apparatus 28.
  • the unified sheet thus produced is then cut up into printing plates which are provided with any desired structure at their ends for attaching them to the printing machine.
  • front and rear edges ll of inal webs. is substantially free of any fibrous the art and further examples are set forth in my copending application Serial No. 312,391, filed January 4, 1940); that it is readily wet by and absorptive of water; and that it is free from any added component or contaminant which either causes the printing ink to displace water previously applied or causes water later applied to displace the ink-receptive image-forming material which has been initially applied to the dry sheet.
  • the sheet is relatively strong and is highly resistant to disintegration by water.
  • both the outer printing face II and the correspondingrear face l2 are each constituted of non-fibrous amyloid cellulose overlaying the cellulose fibers.
  • the non-fibrous amyloid cellulose represented by the stippling in Fig. 2, becomes less ,dense ⁇ there forming a net-work which is integral with the amyloid cellulose on the surface and is bonded to the cellulose fibers with which it is intermingled.
  • the net-works of amyloid cellulose of the upper and lower halves are integrally joined by a dense stratum it of the same amyloid cellulose, free from fiber.
  • the whole plate thus consists of unifled cellulose, contains fibers in its two halves and has extending throughout the plate a continuum of non-fibrous amyloid cellulose which overlays the fibers near each face of the plate and also forms a fiber-free and dense stratum at its Junction between the two constituent sheets.
  • the thickness of the middle stratum I! of fiber-free cellulose is greater than the sum of the two thicknesses of the fiber-free cellulose which overlay the fibers near the two faces [I and I2.
  • the composite web ill, II is but surprisingly the increase in dimension due to absorption of water takes place, in its initial stages, at a much slower rate (one-fourth to onetenth) than in the case of a plate of equal weight and surface-parchmentization consisting of a single layer of parchmentized cellulose. Accordingly, within the limitation of the desired good quality of the impressions, four to ten times as many good impressions can be made.
  • the plate constitutes a valuable improvement over previous backed plates of parchmentized cellulose. There is no tendency of the absorbed water to weaken the bond between the front and back of the sheet. All tendency toward contamination of the printing surface by adhesive bondprinting surface.
  • whichare bonded together to form the material of the plate each may advantageously have a ream weight (24 x 36500 basis) of as low as pounds.
  • the back of the plate cannot exert any contaminating effect of the face of another plate with which it may contact for as indicated above, no added adhesive is applied and hence none is present to permeate the back of the sheet.
  • An advantage of the present invention is that the aggregate hardness of the printing plate is substantially greater than the aggregate hard- 1 ness of a plate of equal total thickness consisting of a front layer of parchmentlzed cellulose, an intermediate bonding layer, and a backing layer of kraft paper, the hardness of the parchmentized cellulose being substantially greater than that of' kraft backing paper.
  • This increased aggregate hardness of the plate results in a crisper image, particularly in typewriting upon the plate.
  • the two component faces of the plate be'approximately balanced as to density, that is, contribute substantially equally to the total density of the plate, in order that the plate may have as little tendency to curl as possible.
  • the expression density is herein used in reference to the compactness of the parchmentized cellulose.- Density of parchmentized cellulose varies with,.and may be satisfactorily expressed in terms of, translucency or opacity, bearing in mind the fact that the opacity of a sheet of given density varies with the thickness so that numerical values of opacity reflect comparative densities only for sheets of the same thickness.
  • the opacity of the parchmentized cellulose printing plate of this invention is a satisfactory criterion of density of the plate as a whole.
  • a parchmentized celluloseprinting plate of the present invention having a surface smoothness of from four to eight as determined by the Bekk smoothness tester and of pound ream weight and about 0.004inch in thickness should in order to have the proper density, have an opacity, as determined by the Bausch & Lomb opacimeter, of not over 0.60; the opacity of this same plate should also preferably be not less than 0.45 because lower opacities than 0.45, at this thickness, indicate such a high degree of parchmentization as results in too great brittleness for convenient handling. Plates of other thicknesses should'have the density of the p ate just described, the values of opacity corresponding to such density and the plate thickness.
  • the outer printing face II should, for typewriting and crayon work, have a smoothness of two or upwards, as determined by the Bekk smoothness tester? while for penmanship, whether writing or line drawing, the smoothness should be four or more. Although satisfactory results can be obtained at values corresponding toglossy surfaces, a smoothness in the optimum range of from four to eight is preferred.
  • the parchmentized cellose of the outer printing face ll necessarily has a positive absorption for water. But an advantageous improvement in life of the image under printing conditions occurs if, as is preferred, the outer printing face has a rate of lateral water diffusion of not more than 25 millimeters in four hours, while having the characteristics ,of density and smoothness as above described.
  • the lateral water diffusion rate herein referred to means the result of a test (as later herein described) of the sheet in its normal condition of'inherent density, and not while in a temporarily altered condition of density which would result, for example, from calendaring the sheetafter formation, it being well known that calendaring may give the sheet increased density, decreased porosity, and a changed diffusion rate, all of which characteristics may be restored to normal by soaking and drying the sheet.
  • the lateral diffusion rate of water in unified cellulosic material is defined as the height (expressed in millimeters) to which distilled water rises in a sheet of said material over a period of 4 hours when the edges thereof are sealed against absorption of water in any convenient manner and when the sheet is suspended over a quiescent bath of said water at room temperature under the following further conditions: (1) the lower end of the sheet is maintained below the level of the bath, this being conveniently accomplished by folding a bit of sheeted block tin over the bottom edge; (2)
  • the machine direction of the sheet is to be parof which time the rise from the marker is measured off in millimeters.
  • a preferred way of causing the parchmentized cellulose to have the desired low rate of lateral water diffusion, without loss of the desirable characteristics as to density and smoothness, consists in an accelerated oxidation of the surface of the material of the plate.
  • the increment in oxidation-products content due to such accelerated oxidation may be employed as a useful measure of the. effectiveness of the accelerated oxidation.
  • Bo oxidationproducts content is here meant the sum of the copper number and percentage cold alkali solubility.
  • Improvement in press performance may be expected to result from still greater increase 4 assaass in oxidation products content due to accelerated oxidation, but the accelerated oxidation should not be carried so far as to-cause marked discoloration or embrittlement.
  • Accelerated oxidation of the surface of the material of the plate may be brought about in a number of ways in which the surface of the plate is accessible to air, oxygen or ozone.
  • exposure to sunlight is effective but is not recommended as a commercial procedure.
  • Exposure to artificially produced ultra violet light is effective.
  • Ultra violet irradiation at 10 inches from a quartz mercury vapor arc lamp for from 2 to 15 minutes, depending upon the reactivity of the stock being treated, will suffice.
  • Other application of non-gaseous oxidizing agents thereto have been tried and found to yield more or less satisfactory results.
  • a suitable method of predisposing the surface to accelerated oxidation by contacting the surface with anhydrous chlorine gas is disclosed in my said copending application Serial No. 312,390, which may be referred to for details of such step. Following such predisposition to accelerated oxidation the desired increase in oxidation-products content will take place upon mere exposure of the surface to air for a time of the order of 1 to 3 weeks.
  • the materialfrom which the outer printing face is made is preferably initially selected from material which does not contain more than 0.5% of resinous extractives. Although some a preciable quantity of resinous extractives will be ound in all commercial grades of papermaking wood pulp availablefor manufacture of the plates, this requirement of an upper limit of 0.5% of resinous extractives can be met by the better grades of the paper-making wood 'pulp which is commercially available.
  • the cellulose of the printing plate is permeable to resinous material in the normal mobile condition of the resinous material. Traces of such mobile resinous material initially contained in the body of the plate tend to migrate through the non-fibrous surface continuum and finally appear on the printing surface of the plate. Even such traces of resinous material. when exposed on thesurface of the plate, become inkreceptive and ink-retentive.
  • the resinous extractives may be thus immobilized by sufllciently aging'either 5 plate from tendency to form ink-retentive spots due to resinous material at its printing surface may be ascertained by an. accelerated test of the printing plate comprising incubating the plate for 4 days at 150 F., irradiating the printing face by ultra violet light from a quartz mercury vapor are lamp (Hanovia type) for '15 minutes at a mean distance of 10 inches, thoroughly saturating the printing surface with the etching solution described in my United States. Patent No.
  • the macroscopically discernible pinpoint ink-retentive spots should not' on the average be more than 0.5 millimeter in diameter andnot of greater occurrence than one such spot for each has the preferred characteristics as to surface smoothness, low lateral water diffusion rate, low content of resinous extractives and substantial immobility of the resinous extractives', and is thus to be the only face intended for printing.
  • a parchmentized cellulose planographic printing plate the printing surface thereof having planographic printing characteristics, and the plate being formed of two superposed sheets of parchmentized cellulose, a continuum of nona fibrous amyloid cellulose extending throughoutv both sheets, said continuum overlaying the fibers near each face of the plate and also constituting a fiber-free and dense stratum at' the Junction between the two sheets, said Junction stratum integrally uniting the two constituent sheets,
  • the plate having a density such as corresponds in a plate of pound ream weight and 0.004 inch thickness to an opacity of from 0.45 to 0.60,
  • the sheet material which forms the printing surface being readily wet by and absorptive of water applied to the printing surface, so as to repel printing ink in the non-imaged areas under printing conditions, but the printing surface having a lateral water difiusion rate of not more than 25 millimeters in four hours.
  • a parchmentized cellulose planographic printing plate the printing surface thereof having planographic printing characteristics
  • u thezplate consisting of two superposed sheets of parchmentized cellulose, a continuum of nonfibrous amyloid cellulose extending throughout e both sheets, said continuum overlaying the fibers near each face of the plate and also constituting a fiber-free and dense stratum at the junc-' sheet which forms the printing surface portionthe wood pulp from which the waterleaf ismade, II of the plate being of wood origin containing traces of resinous material, and said resinous material being in an immobile state to prevent it from migrating to the printing face and there causing autogenous ink-receptive spotting.
  • a parchmentized cellulose planographic printing plate the printing surface thereof having planographic printing characteristics, and the plate being formed of two superposed sheets of parchmentized cellulose, a continuum of nonfibrous amyloid cellulose extending throughout both sheets, said bontinuum overlaying the fibers near each face of the plate and also constituting a fiber-free and dense stratum at the junction between the two sheets, said junction stratum integrally uniting the two constituent sheets and being free of extraneous bonding agents, the plate having a density such as corresponds in a plate of 60 pound ream weight and 0.004 inch thickness to an opacity of from 0.45 to 0.60.
  • a parchmentized cellulose planographic printing plate theprinting surface thereof hav-.
  • the plate being formed of two superposed sheets of parchmentized cellulose, a continuum of nonflbrous amyloid cellulose extending throughout both sheets, said continuum overlaying the fibers near each face of the plate and also constituting a fiber-free and dense'stratum at the junction between the two sheets, said junction stratum integrally uniting the two constituent sheets and being free of extraneous bonding agents, the sheet material which forms the printing surface being readily wet by and absorptive of water applied to the. printing surface, so as to repel printing ink in the non-imaged areas under printing conditions, but the lateral water diffusion rate of the printing surface being not more than 25 millimeters in four hours.
  • a parchmentized cellulose planographic printing-plate the printing surface thereof having planographic printing characteristics, and the plate consisting of two superposed fibrous sheets of parchmentized cellulose, a continuum of non-fibrous amyloid cellulose extending throughout the plate, said continuum overlaying the fibers near each face of the plate and also constituting a fiber-free and dense bonding stratum at the junction between the two sheets, said bonding stratum integrally uniting the two constituent sheets and being free of extraneous bonding agents, and an ink-receptive image on said printing surface and adapted to be retained by said surface when water is subsequently applied thereto in use of the plate.
  • a parchmentized cellulose planographic printing plate the printing surface thereof having planographic printing characteristics, and the plate consisting of two superposed fibrous sheets of parchmentized cellulose, a continuum of non-fibrous amyloid, cellulose extending throughout the plate, said continuum overlaying the fibers near each face of th plate and also constituting a fiber-free and'dense bonding stratum at the Junction between the two sheets; said the plate.
  • the plate having a thickness of approximately 0.004 inch, and an ink-receptive image on said printing surface and adapted to be retained by said surface when water is subsequently applied thereto in use of the plate.
  • a parchmentized cellulose planographic printing plate the printing surface thereof having planographic printing characteristics, and the plate being formed of two superposed sheets of parchmentized cellulose, a continuum of nonfibrous amyloid cellulose extending throughout both sheets, said continuum overlaying the fibers near each face of the plate and also constituting a fiber-free and dense stratum at the junction between the two sheets, said junction stratum integrally uniting the two constituent sheets and being free of extraneous bonding agents, the plate having a density such as corresponds in a plate of 60 pound ream weight and'0.004 inch thickness to an opacity of from 0.45 to 0.60, and an ink-receptive image on said printing surface and adapted to be retained by said surface when water is subsequently applied thereto in use of the plate.
  • a parchmentized cellulose planographic printing plate the printing surface thereof having planographic printing characteristics, and the plate consisting of two superposed fibrous sheets of parchmentized cellulose, a continuum of non-fibrous amyloid cellulose extending throughout the plate, said continuum overlaying the fibers near each face of the plate and also constituting a fiber-free and dense bonding stratum at the junction between the two sheets, said bonding stratum integrally uniting the two constituent sheets and being free of extraneous bonding agents, the density of the two constituent sheets of the plate being substantially the same, and an ink-receptive image on said printing surface and adapted to be retained by said surface when the water is' subsequently applied thereto in use of the plate.
  • a parchmentized cellulose planographic printing plate the printing surface thereof having planographic printing characteristics, and the plate consisting of two superposed fibrous sheets of parchmentized cellulose, a continuum WILLIAM B. WESCOTT.

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  • Printing Plates And Materials Therefor (AREA)
US484833A 1943-01-08 1943-04-28 Planographic printing plate Expired - Lifetime US2348943A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
BE472881D BE472881A (US07223432-20070529-C00017.png) 1943-01-08
NL132918D NL132918B (US07223432-20070529-C00017.png) 1943-01-08
US484833A US2348943A (en) 1943-01-08 1943-04-28 Planographic printing plate
GB434/44A GB570035A (en) 1943-01-08 1944-01-10 Improvements in or relating to planographic printing plates
CH245700D CH245700A (fr) 1943-01-08 1944-04-20 Plaque d'impression planographique en cellulose parcheminée et procédé de fabrication de cette plaque.
FR916254D FR916254A (fr) 1943-01-08 1945-09-11 Plaque dite planographique pour clichés d'imprimerie

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US47167343A 1943-01-08 1943-01-08
US484833A US2348943A (en) 1943-01-08 1943-04-28 Planographic printing plate

Publications (1)

Publication Number Publication Date
US2348943A true US2348943A (en) 1944-05-16

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ID=27043523

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Application Number Title Priority Date Filing Date
US484833A Expired - Lifetime US2348943A (en) 1943-01-08 1943-04-28 Planographic printing plate

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US (1) US2348943A (US07223432-20070529-C00017.png)
BE (1) BE472881A (US07223432-20070529-C00017.png)
CH (1) CH245700A (US07223432-20070529-C00017.png)
FR (1) FR916254A (US07223432-20070529-C00017.png)
GB (1) GB570035A (US07223432-20070529-C00017.png)
NL (1) NL132918B (US07223432-20070529-C00017.png)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2561353A (en) * 1947-02-03 1951-07-24 Finno James Lithographic printing plate
US2635537A (en) * 1950-07-19 1953-04-21 Warren S D Co Paper planographic printing plate with stabilized hydrophilic coating
US2741981A (en) * 1948-06-28 1956-04-17 Warren S D Co Planographic printing plate and treatment thereof
US3031957A (en) * 1957-01-25 1962-05-01 Addressograph Multigraph Printing plates
US4034671A (en) * 1975-01-13 1977-07-12 A. B. Dick Company Method of using an offset lithographic combination master blanket sheet

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2561353A (en) * 1947-02-03 1951-07-24 Finno James Lithographic printing plate
US2741981A (en) * 1948-06-28 1956-04-17 Warren S D Co Planographic printing plate and treatment thereof
US2635537A (en) * 1950-07-19 1953-04-21 Warren S D Co Paper planographic printing plate with stabilized hydrophilic coating
US3031957A (en) * 1957-01-25 1962-05-01 Addressograph Multigraph Printing plates
US4034671A (en) * 1975-01-13 1977-07-12 A. B. Dick Company Method of using an offset lithographic combination master blanket sheet

Also Published As

Publication number Publication date
BE472881A (US07223432-20070529-C00017.png)
NL132918B (US07223432-20070529-C00017.png)
CH245700A (fr) 1946-11-30
GB570035A (en) 1945-06-19
FR916254A (fr) 1946-12-02

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