Claims
- 1. A method for making a printing member for a press with dampening comprising the steps of:
- forming a metal body with an exposed oxidized surface having a grained surface structure which renders said surface hydrophilic, and
- heating said body surface at selected image points thereon without contacting said surface and without penetrating through said body so that there is a transformation of said surface structure which renders said surface oleophilic at said image points.
- 2. The method defined in claim 1 and including the step of continuing said heating until molten metal flows from the interior of said body through said surface structure at said image points.
- 3. The method defined in claim 2 including the step of forming said body of aluminum.
- 4. The method defined in claim 2 including the step of forming said body as a flexible layer which can extend around a print cylinder.
- 5. The method define in claim 7 including the step of forming said body as a rigid cylinder having an oxidized cylindrical surface.
- 6. The method defined in claim 1 including the step of heating said surface by spacing said surface opposite a point electrode and establishing a potential difference between said electrode and said body at said image points so as to produce spark discharges between said electrode and said surface at said image points.
- 7. The method defined in claim 6 including the step of producing said spark discharges by applying momentary voltage pulses image-wise between said electrode and said body so that a multiplicity of image-representing oleophilic spots are formed on the otherwise hydrophilic body surface.
- 8. The method defined in claim 7 and including the step of pulsing said electrode negative relative to said body.
- 9. The method defined in claim 1 including the step of
- coating said surface with waterless ink after the body surface is heated at said selected image points;
- applying dampening liquid to the coated surface to dislodge the ink from said surface except at said image points thereon thereby leaving ink spots at said image points; and
- setting said ink spots.
- 10. The method defined in claim 9 including the steps of
- selecting a radiation curable ink; and
- applying radiation to said ink spots to set same.
- 11. A printing member for a press with dampening comprising
- a metal body having an exposed oxidized surface with a grained surface structure which renders said surface hydrophilic, said body surface being heated at selected image points thereon without contacting said surface and without penetrating through said body whereby there is a transformation of said grained surface structure which renders said surface oleophilic at said image points.
- 12. The printing member defined in claim 11 wherein said body is of aluminum.
- 13. The printing member defined in claim 11 wherein said body is a flexible layer which can extend around a print cylinder.
- 14. The printing member defined in claim 11 wherein said body is a rigid cylinder and said oxidized surface is a cylindrical surface of said cylinder.
- 15. The printing member defined in claim 11 and further including a coating of waterless ink covering said transformed surface structure.
- 16. The printing member defined in claim 15 wherein said ink is a radiation curable link.
RELATED APPLICATION
This application is a division of Ser. No. 234,475, filed Aug. 19, 1988, now Pat. No. 4,911,075.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4063949 |
Uhlig et al. |
Dec 1977 |
|
4082902 |
Suzuki et al. |
Apr 1978 |
|
4718340 |
Love, III |
Jan 1988 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
0062051 |
Apr 1983 |
JPX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
234475 |
Aug 1988 |
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