| (19) |
 |
|
(11) |
EP 0 027 698 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
30.12.1981 Bulletin 1981/52 |
| (43) |
Date of publication A2: |
|
29.04.1981 Bulletin 1981/17 |
| (22) |
Date of filing: 06.10.1980 |
|
|
| (84) |
Designated Contracting States: |
|
AT BE CH DE FR GB IT LI LU NL SE |
| (30) |
Priority: |
22.10.1979 GB 7936520
|
| (71) |
Applicant: The Wiggins Teape Group Limited |
|
() |
|
|
| |
|
| (54) |
Sheet material carrying an unobtrusive image and method for its production |
(57) An unobtrusive image is applied to paper or other sheet material by means of a charged
droplet printer, for example an inkjet printer. The unobtrusive image applied may
perform the function usually associated with a watermark in paper, but in contrast
to a watermark, may be applied to papers during their production on high speed wide
deckle machines or to coated papers. The method is particularly suitable for unobtrusively
imaging pressure-sensitive copying material.