EP0159985A1 - Improvements in or relating to electro-sensitive materials - Google Patents
Improvements in or relating to electro-sensitive materialsInfo
- Publication number
- EP0159985A1 EP0159985A1 EP84900089A EP84900089A EP0159985A1 EP 0159985 A1 EP0159985 A1 EP 0159985A1 EP 84900089 A EP84900089 A EP 84900089A EP 84900089 A EP84900089 A EP 84900089A EP 0159985 A1 EP0159985 A1 EP 0159985A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- recording sheet
- layer
- opaque
- protective layer
- sheet
- 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.)
- Ceased
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
- B41M5/00—Duplicating or marking methods; Sheet materials for use therein
- B41M5/24—Ablative recording, e.g. by burning marks; Spark recording
- B41M5/245—Electroerosion or spark recording
-
- 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
- G03F7/20—Exposure; Apparatus therefor
- G03F7/2002—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image
- G03F7/2014—Contact or film exposure of light sensitive plates such as lithographic plates or circuit boards, e.g. in a vacuum frame
- G03F7/2016—Contact mask being integral part of the photosensitive element and subject to destructive removal during post-exposure processing
- G03F7/202—Masking pattern being obtained by thermal means, e.g. laser ablation
Definitions
- the present invention relates to an electro-sensitive recording sheet on which written or pictorial records may be inscribed by means of a recording stylus and to the use of such a recording sheet in the preparation of offset lithographic plates.
- the over-layer was coated with a solid and electrically partially conductive over-layer formed from a mixture of electrically partially conductive solid material and a film forming resin material.
- the over-layer was to be totally removable by treatment with a solvent which left the under-layer and over-layer intact, the protective over-layer serving to inhibit mechanical abrasion of the under-layer during ins cription of the blank with an electrical stylus.
- an eletrical current was passed between the blank and a stylus while producing relative movement therebetween so as to remove locally bo th the protecti ve layer and the over- lay er .
- the inscribed blank was treated with solvent to remove the remainder of the protective layer whilst leaving the over- layer and the under-layer intact.
- Lithos can plates can be made to produce good line reproduction as well as excellent tone reproduction. By using colour filters it is possible to cut four colour separation plates to produce process colour work. But such plates have the disadvantage of lasting only for relatively short runs and they cannot ordinarily produce more than 2000 copies . This is because the hydrophi lic part of the plate in the practical commerically sold version is a thin vacuum deposited aluminium layer. It is impossible to increase the run life of lithoscan plates by increasing the thickness of the aluminium layer because doing so adversely af fects the electrical properties of the plate system, which reduces spark erosion and results in weak offset litho copies.
- the coating could be fused by a trace electrode or stylus i nto tran sparency a l ong the path fo l low ed by the e l ectrod e .
- a trace electrode or stylus i nto tran sparency a l ong the path fo l low ed by the e l ectrod e In the pra cti ca l embodi ment a fi l m of polyester or other transparent material was coated with a thin optical ly trans mis s ive deposit of aluminium coated with an electrosensitised blushed lacquer or other coating material that preferably fused to transparency (as opposed to disintegrating) on pas sage of an electrical current.
- the invention is based on the dis covery that a transparent carrier sheet or under-layer can be coated with an opaque aluminium over layer and then with a second opaque protective layer having el ectrically conductive particles dispersed in a res in to produce a recording sheet , that both the protective layer and the over-layer can be eroded away by passing electric current between the recording sheet and a moving electrical stylus , and that the resulting positive or negative imaged recording sheet can be employed in transmis sion either to produce fi lm intermediate positives or negatives or by contacting with pre-sensiti zed offset litho plates to produce long run plates capable of producing tens or even thousands of copies.
- the invention provides a normally opaque recording sheet that can be converted by spark erosion into an image of an original that has low background in areas corresponding to black areas of the original, comprising in combination: an optically transmissive insulating carrier sheet; an opaque layer of aluminium, chromium or nickel deposited on the carrier sheet which layer is from 0.025 to 1 micron thick and has a surface resistance of from 2 to 0.5 ohms per square; and insoluble opaque spark-erodible protective layer comprising electrically conductive particles dispersed in a resin and coated onto the aluminium layer in an amount of from 3 to 18 g.s .m.
- the under-layer is coated with a layer of metal, preferably vacuum deposited aluminium. It is a requirement that the over-layer should be capable of acting as an electrode for the stylus current during inscription of the recording sheet whilst at the same time being capable of being removed by the stylus . If the resistivity is greater than 2 ohms per square the optical transmissivity of the over-layer will start to become significant. If the resistivity is less than 0.3 ohms per square the over-layer cannot be eroded successfully. In Hills et al the over-layer is transparent and not opaque and any erosion thereof while inscription is taking place is incidental and contributes to image formation as it does in the present invention.
- the over-layer In addition to its opacity, the over-layer must consist of a resin or a mixture of resins plus a pigment or a mixture of pigments and must have a coating weight of from 3 to 18 grams per square metre. It should have good handling properties and be sufficiently hard and abrasion
- Non cross-linked water soluble resins are unsuitable as the resin or as a major constituent of the resin " mixture because they are attacked by sweat from the hands.
- Examples of preferred resins are polyvinyl acetates, acrylic resins, vinyl/acrylate copolymers and styrenated resins.
- the protective layer should be sufficiently pigmented that it contributes significantly to the total opacity of the two layers (the protective layer and the over-layer) to UV and visible light. It is preferred that the protective layer should be entirely opaque to light so that any slight coating faults in the metal over-layer are entirely obscured.
- the conductive pigment particles present are preferably of zinc oxide, zinc sulphide or carbon black and they are preferably present in an amount such as will give a DC breakdown voltage between an electrical stylus and the over-layer of from 10 to 400 volts.
- zinc oxide or zinc sulphide are incorporated into the protective layer, they are preferably present in an amount of from 14% to 50% by total dry weight and in order to achieve good opacity up to 40% by total dry weight of titanium dioxide may be added.
- carbon black is employed it should have a high electrical resistivity and suitable carbon blacks incude Mogul L, Special Black 4 and Raven 1255.
- the carbon black may be present in an amount of from 5 to 20% by total dry weight and it may be desirable to incorporate 25 to 40% by total dry weight of a filler such as a clay.
- the protective layer may be applied as by roller coating a suspension of the pigment particles in a solution of the resin in a volatile organic solvent such as toluene and allowing the solvent to evaporate.
- the recording sheet is inscribed in an electroresponsive spark erosion scanner in which a current is passed between the blank and the stylus while relative movement is produced therebetween.
- O. ⁇ PI is locally exposed.
- the protective layer serves to prevent abrasion of the over-layer while this is taking place.
- a cylindrical drum is mounted concentrically on a rotatable shaft.
- An original document to be reprodu ced and a f lexib le e l ectro- responsi ve recording sheet are stretched side-by-side around the cylindrica l sur face of the drum .
- On an ax ia lly displaceable shaft parallel to the rotatable shaft is mounted a s tyl us -carrying arm that supports an electronically operable stylus adjacent to the blank.
- An optical scanning device is also mounted on the shaft and it has a photohead supported adjacent to the document.
- the shaft As the shaft is rotated, the blank and the document rotate with the drum. Simultaneous ly, the shaft is made to traverse the drum axially so that the photohead scans the surface of the document and the stylus synchronously scans the surface of the recording sheet.
- the original can be inscribed successively using red, blue and green filters . B ecause the pattern cut by the stylus is random, there is no Moire effect when the three resultant images are combined even where the original is screened.
- a coloured original can be s canned to produce an image that can be used for black and white printing.
- the imaged recording sheet may be used directly to produce a lithographic plate by direct contact exposure after which the exposed plate is treated to remove non- image areas .
- a photographic proofing material may be exposed through the ins cribed recording sheet and developed to produce an internegative which is then used to expose a presens itised offs et lithographic plate .
- the invention is believed to be particularly suited to the needs of small jobbing printers who wish to offer a colour printing facility without involving themselves in time consum ing procedures and elaborate equipment.
- I t provides a method for reproduction from a screened printed copy without resorting to photographic origination. Also it forms the basis of a process not involving a darkroom.
- the invention is illustrated in the following
- a formulation of the following composition was made up and ground in a ball mill for 4 hours
- Synolac 608S (vinyl acrylic copolymer resin supplied by Cray Valley Products) 13 grams Ethyl Cellulose K5000 (supplied by Hercules)
- Example II A formulation of the following composition was treated as in Example I but giving a black opaque top layer at a solids weight of 12 grams per square metre.
Abstract
Feuille d'enregistrement normalement opaque pouvant être convertie au moyen d'une érosion par étincelles en une image d'un original possédant un fond clair dans les parties correspondantes aux parties noires de l'original. Elle comprend une feuille de support isolante optiquement transmettrice, une couche opaque d'aluminium, de chrome ou de nickel déposée sur la feuille de support, cette couche ayant une épaisseur de 0,025 à 1 micron et une résistance de surface de 2 à 0,5 ohms par carré, ainsi qu'une couche de protection pouvant être érodée par étincelles, insoluble et opaque, contenant des particules électriquement conductrices dispersées dans une résine et enduisant la couche d'aluminium dans une quantité de 3 à 18 g/m2. Il est possible d'éroder la couche de protection et la couche supérieure en faisant passer un courant électrique entre la feuille d'enregistrement et un style électrique mobile. La feuille d'enregistrement résultante imprimée positivement ou négativement peut être utilisée en transmission soit pour produire des positifs ou des négatifs intermédiaires de film, soit par contact avec des plaques lithographiques offset présensibilisées afin de produire des plaques lithographiques de tirage prolongé. La couche supérieure opaque et la partie imprimante opaque restent dans des parties non imprimantes et sont présentes dans des parties imprimées, de façon à donner un fond clair.A normally opaque recording sheet which can be converted by spark erosion into an image of an original having a light background in portions corresponding to black portions of the original. It comprises an optically transmitting insulating support sheet, an opaque layer of aluminum, chromium or nickel deposited on the support sheet, this layer having a thickness of 0.025 to 1 micron and a surface resistance of 2 to 0.5 ohms per square, as well as an opaque, insoluble spark-erodible protective layer containing electrically conductive particles dispersed in a resin and coating the aluminum layer in an amount of 3 to 18 g/m2. It is possible to erode the protective layer and the top layer by passing an electric current between the recording sheet and a moving electric pen. The resulting positively or negatively printed recording sheet can be used in transmission either to produce intermediate positives or negatives of film, or by contact with presensitized offset lithographic plates to produce extended run lithographic plates. The opaque upper layer and the opaque printing part remain in non-printing parts and are present in printed parts, so as to give a light background.
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8235737 | 1982-12-15 | ||
GB8235737 | 1982-12-15 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0159985A1 true EP0159985A1 (en) | 1985-11-06 |
Family
ID=10534999
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP84900089A Ceased EP0159985A1 (en) | 1982-12-15 | 1983-12-08 | Improvements in or relating to electro-sensitive materials |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0159985A1 (en) |
JP (1) | JPS59114543A (en) |
IL (1) | IL70435A0 (en) |
WO (1) | WO1984002308A1 (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB8702281D0 (en) * | 1987-02-02 | 1987-03-11 | Figov M | Electro-responsive recording sheet |
WO1991011754A1 (en) * | 1990-01-31 | 1991-08-08 | Presstek, Inc. | Improved method and means for producing photomasks |
US5217829A (en) * | 1990-02-22 | 1993-06-08 | Presstek, Inc. | Method for producing photomasks |
US5354633A (en) * | 1993-09-22 | 1994-10-11 | Presstek, Inc. | Laser imageable photomask constructions |
JP3515836B2 (en) * | 1995-08-29 | 2004-04-05 | 株式会社きもと | Plate material for lithographic printing and a method of making a lithographic printing plate using the same |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3411948A (en) * | 1964-04-08 | 1968-11-19 | Hewlett Packard Co | Electrosensitive recording medium |
US3514325A (en) * | 1966-11-17 | 1970-05-26 | Hewlett Packard Co | Electrosensitive recording article and method of making the same |
GB1244177A (en) * | 1968-03-04 | 1971-08-25 | Marconi Internat Marine Compan | Improvements in or relating to electro-sensitive record mediums |
AU6984274A (en) * | 1973-06-08 | 1975-12-11 | Grace W R & Co | Printing plate process |
US4086853A (en) * | 1973-07-11 | 1978-05-02 | Vickers Limited | Lithographic printing plate preparation |
DE2434105B2 (en) * | 1974-07-16 | 1976-06-24 | Robert Bosch Gmbh, 7000 Stuttgart | ELECTRO-SENSITIVE RECORDING MEDIA AND METHOD FOR ITS MANUFACTURING |
DE2553385A1 (en) * | 1975-11-27 | 1977-06-08 | Siemens Ag | PROCESS FOR MANUFACTURING PRECISE PATTERNS IN THIN METALIZATIONS ON PLASTIC FILM |
GB1545726A (en) * | 1976-07-08 | 1979-05-16 | Sekisui Chemical Co Ltd | Electric discharge recording method and material |
CA1144418A (en) * | 1979-12-17 | 1983-04-12 | Ari Aviram | Erosion process for generation of offset masters |
-
1983
- 1983-06-14 JP JP58105073A patent/JPS59114543A/en active Pending
- 1983-12-08 EP EP84900089A patent/EP0159985A1/en not_active Ceased
- 1983-12-08 WO PCT/GB1983/000327 patent/WO1984002308A1/en not_active Application Discontinuation
- 1983-12-12 IL IL70435A patent/IL70435A0/en unknown
Non-Patent Citations (1)
Title |
---|
See references of WO8402308A1 * |
Also Published As
Publication number | Publication date |
---|---|
IL70435A0 (en) | 1984-03-30 |
JPS59114543A (en) | 1984-07-02 |
WO1984002308A1 (en) | 1984-06-21 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19850607 |
|
AK | Designated contracting states |
Designated state(s): DE FR GB |
|
17Q | First examination report despatched |
Effective date: 19870108 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED |
|
18R | Application refused |
Effective date: 19880515 |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: JUDE, RODNEY FRANCIS Inventor name: FIGOV, MURRAY Inventor name: STEPHENSON, RAYMOND OWEN |