CA1088363A - Smoothing roughened polytetrafluoroethylene film by exposing to laser radiation - Google Patents
Smoothing roughened polytetrafluoroethylene film by exposing to laser radiationInfo
- Publication number
- CA1088363A CA1088363A CA253,896A CA253896A CA1088363A CA 1088363 A CA1088363 A CA 1088363A CA 253896 A CA253896 A CA 253896A CA 1088363 A CA1088363 A CA 1088363A
- Authority
- CA
- Canada
- Prior art keywords
- roughened
- film
- printing
- exposing
- radiation
- 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
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
- B41C1/00—Forme preparation
- B41C1/10—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme
- B41C1/1041—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme by modification of the lithographic properties without removal or addition of material, e.g. by the mere generation of a lithographic pattern
-
- 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
- B41N1/003—Printing plates or foils; Materials therefor with ink abhesive means or abhesive forming means, such as abhesive siloxane or fluoro compounds, e.g. for dry lithographic printing
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Manufacture Or Reproduction Of Printing Formes (AREA)
- Photosensitive Polymer And Photoresist Processing (AREA)
- Printing Plates And Materials Therefor (AREA)
Abstract
Abstract of the Disclosure This invention relates to an improvement in the process for the manufacture of a planographic printing form by imagewise exposure to radiation of a roughened polytetrafluoroethylene film, the improvement comprising exposing the film to laser light until the film surface is smooth.
Description
~ 108~3363 K-2395 PROCESS FOR THE PRODUCTION OF PLANOGRAPHIC PRINTING ~ -FORMS BY MEANS OF LASER BEAMS
.
The present invention relates to a process for the production of planographic printing forms in which a roughened polytetrafluoroethyLene film is imagewise expased to a laser beam and ink repellent non-image areas are thereby produced.
In the photomechanical production of planographic prLnting forms a copying material usually provided with a light-sensitive layer is imagewise exposed to light and then developed with a suitable developer solution, whereby oleophilic image areas and hydrophilic non-image areas are obtained. The oleophilic image areas of the layer usually re-main after development, whereas the non-image areas are usually dissolv-ed during development, leaving the carrier surface bared.
For development, organic solvents or alkaline or acidic aqueous -solutions are generally used, depending upon the nature of the layer. In working with these solutions, certain safety measures, for example dis-tillation or neutralization, must be observed. It would be desirable, therefore, to eliminate such developer solutions.
It is known that polytetrafluoroethylene films having a smooth surface repel all printing ink ~greasy ink and water-based ink) and that polytetrafluoroethylene films having a roughened surface are ink recep-tive.
The films are usually roughened in solutions of sodium in liquid ammonia or by means of a corona discharge. Further methods are de-scribed in the journal "Kunststoff-Rundschau" (1964), Volume 10, pages 574 ff.
It is also known to use polytetrafluoroethylene films as printing form carriers for lithographic printing. U. S. Patent No. 3,368,483, - ~ K-2395 ` 1088363 discloses the production of a lithographic two-color printing form in-cluding the following steps:
1. roughenlng of polytetrafluoroethylene,
.
The present invention relates to a process for the production of planographic printing forms in which a roughened polytetrafluoroethyLene film is imagewise expased to a laser beam and ink repellent non-image areas are thereby produced.
In the photomechanical production of planographic prLnting forms a copying material usually provided with a light-sensitive layer is imagewise exposed to light and then developed with a suitable developer solution, whereby oleophilic image areas and hydrophilic non-image areas are obtained. The oleophilic image areas of the layer usually re-main after development, whereas the non-image areas are usually dissolv-ed during development, leaving the carrier surface bared.
For development, organic solvents or alkaline or acidic aqueous -solutions are generally used, depending upon the nature of the layer. In working with these solutions, certain safety measures, for example dis-tillation or neutralization, must be observed. It would be desirable, therefore, to eliminate such developer solutions.
It is known that polytetrafluoroethylene films having a smooth surface repel all printing ink ~greasy ink and water-based ink) and that polytetrafluoroethylene films having a roughened surface are ink recep-tive.
The films are usually roughened in solutions of sodium in liquid ammonia or by means of a corona discharge. Further methods are de-scribed in the journal "Kunststoff-Rundschau" (1964), Volume 10, pages 574 ff.
It is also known to use polytetrafluoroethylene films as printing form carriers for lithographic printing. U. S. Patent No. 3,368,483, - ~ K-2395 ` 1088363 discloses the production of a lithographic two-color printing form in-cluding the following steps:
1. roughenlng of polytetrafluoroethylene,
2. sensitizing with the ald of a water-soluble diazo compound,
3. first exposure under a (negative) original for the first (water-based) printing ink and devetopment, and
4. second exposure under a (positive) original, whereby the roughened surface is to be changed back into its original smooth condition in the areas struck by light.
The result is a printlng form comprising three areas that have -different affinities towards printing ink and thus allowing,among other thlngs, to obtaln a two-color print with greasy and water-based printing ink from one printing form.
A considerable disadvantage of this process is the low light-sensitivity to UV llght of the roughened polytetrafluoroethytene surface. -~It has been found that exposure to conventlonal UV light sources must be sustained for many hours in order to change the roughened, ink re-ceptive material back into its original ink repellent state.
A simSlar process is disclosed in DL Patent No. 103,977, in which polyvinyl chloride surfaces or polyamide surfaces are Imagewise exposed to high-energy radiation. Thus their wetting propertles relative to liquids are changed. There is no information as to the nature of the high-energy radiation and the llquid used for measuring the contact angle. It Ss not evident whether or not the treatment described in the above-mentioned patent leads at all to a differentiation sufficient for practical use in planographic printing.
'` ~0~38363 K-2395 In German Offenlegungsschrift No. 1,960,959, a process for the production of printing plates is described in which a relief pattern is engraved in the surface of a polymer, e.g. a tetrafluoroethylene polymer, ~ ~
by means of laser radiation. This process also requires relatively high ~ -energies, i.e. Iong exposure tlmes, since relief depths of about 0.2 to 0.8 mm are produced (see Table I, page 14).
It is the object of the present invention to provide a process for the production of planographic printing plates by exposure to light of light-insensitive or of iow light-sensitivity material, which process works with considerably shorter exposure times.
The invention is a process for the production of planographic printing forms by imagewise irradiation of a roughened polytetrafluoro-ethylene film.
In the process, the film is exposed to laser light until the film surface is smooth.
The invention achieves a reduction of the exposure time from several hours to a few minutes, through the use of U~J light.
The process according to the invention provides a new and ex-ceptionally simple method of producing planographic printing forms. The recording material used ln the process is relatively insensitive to day-light and artificial light as well as to aging. It has a practically un-Iimited storage life. The only process step is the imagewise exposure of the material to laser beams.
The exposed plate is placed into an offset printing machine with-out further treatment, and greasy printing ink and fountain solution are applied in the usual manner. In the case of an optimum differentiation between image areas and non-image areas, and if printing ink adjusted accordingly is used, no fountain solution is required in the offset ..
. - . . . .............. .
: , .
`~ 1088363 K-2395 printing machine, i.e. printing may be carried out according to the dry offset process with printing ink based on oil.
Lasers suitable for the purposes of the invention are efficient lasers which emit radiation having shorter wavelengths, for example Ar-lasers, krypton-ion lasers and the like, that emit radiation of wave-lengths between 300 and 600 nm. A 3 to 30 watts argon laser having an amperage of between 15 and 35 amperes and linear deflection speeds of more than 10 cm/sec are preferred.
By focusing the làser beam by means of an optical system, foci are produced on the surface to be irradiated that have a diameter of less `~
than 50,4m.
It is suitable to control the laser beam with the aid of a prede-termined linear movement and/or screen movement. The process and apparatus for controlling the laser beam by means of computers as well as focusing, modulation or deflection of the beam are described, for example, in German Offenlegungsschriften Nos. 2,318,133, pages 3 ff; 2,344,233, pages 8 ff, and in U. S. Patents Nos. 3,7S1,587; -3,745,586; 3,747,117; 3,475,760; 3,506,779, and 3,664,737.
A particular advantage of the process according to the invention is that the carrier whlch has been imagewise exposed to radiation may be placed into an offset printing machine either immediately or after storage for any time desired, and printing may be begun immediately.
The need for development or decoating of the image-free areas of the - carrier, as is necessary for the known customer-coated and presensi-tized offset printing plates and which often must be carried out in bulky and exper.sive developing machines, is completely eliminated. This advantage considerably supports the efforts made to speed up and rationalize offset printing.
_ 4 _ ~1088363 K-2 3 9 5 The invention wiLl be further illustrated by reference to the following specific example:
Example In order to roughen it, a polytetrafluoroethylene film is dipped for 60 seconds into a 3 per cent by weight solution of sodium in liquid ammonia and is then cleaned, rinsed and dried. The roughening causes the surface tension to increase from 18 dynes/cm to more than 60 dynes/cm, and the surface becomes a dark brown color. For the manu~
facture of the printing form, imagewise exposure to radiation is carried out with the aid of an argon/krypton laser having a total capacity of 13 watts and a current intensity o~ 32 amperes, the deflection speed amounting to more than 100 mm/sec.
By focusing the beam by means of an optical system, a focus -having a diameter of about 7~m is produced in the case of a power den-sity of about 7.5 megawatts/cm2.
The areas exposed to radiation have a light color. The printlng film is put into an offset printing machine without further treatment and printing is begun, the non-exposed areas accepting greasy printing ink.
More than 40,000 prints are obtained.
It will be obvious to those skilled in the art that many modifi-cations may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
The result is a printlng form comprising three areas that have -different affinities towards printing ink and thus allowing,among other thlngs, to obtaln a two-color print with greasy and water-based printing ink from one printing form.
A considerable disadvantage of this process is the low light-sensitivity to UV llght of the roughened polytetrafluoroethytene surface. -~It has been found that exposure to conventlonal UV light sources must be sustained for many hours in order to change the roughened, ink re-ceptive material back into its original ink repellent state.
A simSlar process is disclosed in DL Patent No. 103,977, in which polyvinyl chloride surfaces or polyamide surfaces are Imagewise exposed to high-energy radiation. Thus their wetting propertles relative to liquids are changed. There is no information as to the nature of the high-energy radiation and the llquid used for measuring the contact angle. It Ss not evident whether or not the treatment described in the above-mentioned patent leads at all to a differentiation sufficient for practical use in planographic printing.
'` ~0~38363 K-2395 In German Offenlegungsschrift No. 1,960,959, a process for the production of printing plates is described in which a relief pattern is engraved in the surface of a polymer, e.g. a tetrafluoroethylene polymer, ~ ~
by means of laser radiation. This process also requires relatively high ~ -energies, i.e. Iong exposure tlmes, since relief depths of about 0.2 to 0.8 mm are produced (see Table I, page 14).
It is the object of the present invention to provide a process for the production of planographic printing plates by exposure to light of light-insensitive or of iow light-sensitivity material, which process works with considerably shorter exposure times.
The invention is a process for the production of planographic printing forms by imagewise irradiation of a roughened polytetrafluoro-ethylene film.
In the process, the film is exposed to laser light until the film surface is smooth.
The invention achieves a reduction of the exposure time from several hours to a few minutes, through the use of U~J light.
The process according to the invention provides a new and ex-ceptionally simple method of producing planographic printing forms. The recording material used ln the process is relatively insensitive to day-light and artificial light as well as to aging. It has a practically un-Iimited storage life. The only process step is the imagewise exposure of the material to laser beams.
The exposed plate is placed into an offset printing machine with-out further treatment, and greasy printing ink and fountain solution are applied in the usual manner. In the case of an optimum differentiation between image areas and non-image areas, and if printing ink adjusted accordingly is used, no fountain solution is required in the offset ..
. - . . . .............. .
: , .
`~ 1088363 K-2395 printing machine, i.e. printing may be carried out according to the dry offset process with printing ink based on oil.
Lasers suitable for the purposes of the invention are efficient lasers which emit radiation having shorter wavelengths, for example Ar-lasers, krypton-ion lasers and the like, that emit radiation of wave-lengths between 300 and 600 nm. A 3 to 30 watts argon laser having an amperage of between 15 and 35 amperes and linear deflection speeds of more than 10 cm/sec are preferred.
By focusing the làser beam by means of an optical system, foci are produced on the surface to be irradiated that have a diameter of less `~
than 50,4m.
It is suitable to control the laser beam with the aid of a prede-termined linear movement and/or screen movement. The process and apparatus for controlling the laser beam by means of computers as well as focusing, modulation or deflection of the beam are described, for example, in German Offenlegungsschriften Nos. 2,318,133, pages 3 ff; 2,344,233, pages 8 ff, and in U. S. Patents Nos. 3,7S1,587; -3,745,586; 3,747,117; 3,475,760; 3,506,779, and 3,664,737.
A particular advantage of the process according to the invention is that the carrier whlch has been imagewise exposed to radiation may be placed into an offset printing machine either immediately or after storage for any time desired, and printing may be begun immediately.
The need for development or decoating of the image-free areas of the - carrier, as is necessary for the known customer-coated and presensi-tized offset printing plates and which often must be carried out in bulky and exper.sive developing machines, is completely eliminated. This advantage considerably supports the efforts made to speed up and rationalize offset printing.
_ 4 _ ~1088363 K-2 3 9 5 The invention wiLl be further illustrated by reference to the following specific example:
Example In order to roughen it, a polytetrafluoroethylene film is dipped for 60 seconds into a 3 per cent by weight solution of sodium in liquid ammonia and is then cleaned, rinsed and dried. The roughening causes the surface tension to increase from 18 dynes/cm to more than 60 dynes/cm, and the surface becomes a dark brown color. For the manu~
facture of the printing form, imagewise exposure to radiation is carried out with the aid of an argon/krypton laser having a total capacity of 13 watts and a current intensity o~ 32 amperes, the deflection speed amounting to more than 100 mm/sec.
By focusing the beam by means of an optical system, a focus -having a diameter of about 7~m is produced in the case of a power den-sity of about 7.5 megawatts/cm2.
The areas exposed to radiation have a light color. The printlng film is put into an offset printing machine without further treatment and printing is begun, the non-exposed areas accepting greasy printing ink.
More than 40,000 prints are obtained.
It will be obvious to those skilled in the art that many modifi-cations may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In the process for the production of a planographic printing form by imagewise exposure to radiation of a roughened polytetrafluoroethylene film, the improvement wherein said exposure to radiation comprises exposing the film to laser light until the film surface is smooth.
2. A process according to claim 1 in which the laser light has a wavelength in the range of about 300 to 600 nm.
3. A process according to claim 2 in which the laser is an argon laser.
4. A process accord to claim 1 wherein said roughened film is obtained by treatment with a solution of sodium in liquid ammonia.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP2524701.2 | 1975-06-04 | ||
| DE19752524701 DE2524701A1 (en) | 1975-06-04 | 1975-06-04 | PROCESS FOR THE PRODUCTION OF FLAT PRINTING FORMS WITH LASER BEAMS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1088363A true CA1088363A (en) | 1980-10-28 |
Family
ID=5948177
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA253,896A Expired CA1088363A (en) | 1975-06-04 | 1976-06-02 | Smoothing roughened polytetrafluoroethylene film by exposing to laser radiation |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS60228B2 (en) |
| CA (1) | CA1088363A (en) |
| DE (1) | DE2524701A1 (en) |
| FR (1) | FR2313209A1 (en) |
| GB (1) | GB1511626A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2725093C3 (en) * | 1977-06-03 | 1984-04-05 | Rudolf Dr.-Ing. 2300 Kiel Hell | Printing process and arrangement for its implementation |
| JPH0671787B2 (en) * | 1983-12-21 | 1994-09-14 | 旭化成工業株式会社 | Method for producing lithographic printing plate |
| JPS62156523U (en) * | 1986-03-28 | 1987-10-05 | ||
| DE3714157A1 (en) * | 1987-04-28 | 1988-11-17 | Hans Grabensee | Method for offset printing and offset printing plate |
| US5713287A (en) * | 1995-05-11 | 1998-02-03 | Creo Products Inc. | Direct-to-Press imaging method using surface modification of a single layer coating |
| JPH08310148A (en) * | 1995-05-16 | 1996-11-26 | Nippon Paint Co Ltd | Laser direct engraving lithographic printing plate material requiring no liquid developing step, and printing method using the same |
| GB9714526D0 (en) * | 1997-07-11 | 1997-09-17 | Horsell Graphic Ind Ltd | Pattern Formation |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3368483A (en) * | 1965-05-10 | 1968-02-13 | Duriron Co | Two-color lithographic printing form, method of preparing same, and method of use |
| DE2043140C3 (en) * | 1970-08-31 | 1981-06-19 | Agfa-Gevaert Ag, 5090 Leverkusen | Method for producing a planographic printing plate and device for carrying out the method |
| DE2302398A1 (en) * | 1973-01-18 | 1974-07-25 | Du Pont Deutschland | Direct production of polymeric printing plates - using laser beam |
-
1975
- 1975-06-04 DE DE19752524701 patent/DE2524701A1/en not_active Withdrawn
-
1976
- 1976-06-02 GB GB2276776A patent/GB1511626A/en not_active Expired
- 1976-06-02 JP JP6444776A patent/JPS60228B2/en not_active Expired
- 1976-06-02 CA CA253,896A patent/CA1088363A/en not_active Expired
- 1976-06-03 FR FR7616787A patent/FR2313209A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| GB1511626A (en) | 1978-05-24 |
| JPS60228B2 (en) | 1985-01-07 |
| FR2313209B1 (en) | 1978-05-19 |
| JPS5212006A (en) | 1977-01-29 |
| FR2313209A1 (en) | 1976-12-31 |
| DE2524701A1 (en) | 1976-12-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |