Paper including watermarks and/or embossing
The invention relates to improvements in paper, and in particular to the use of watermarks and/or embossings for strengthening paper sheets and documents made therefrom. The invention therefore provides a sheet of paper having at least three corners and three sides joined at said corners, wherein corner reinforcing watermarks are provided at each of said corners. Alternatively, or in addition, corner reinforcing embossings are provided at each of said corners.
1. A sheet of security paper having at least three edges and at least three corners, said corners being formed where a pair of adjacent edges adjoin each other, said sheet having a mean paper grammage and a mean stiffness, and said sheet including reinforcing watermarks in each of said corners, wherein said reinforcing watermarks comprise a plurality of substantially parallel stripes, each of which stripes substantially extends at an angle between 35° and 55° from an edge of the sheet, said stripes having a paper grammage greater than said mean paper grammage and providing a stiffness in said corners greater than said mean paper stiffness to thereby increase the paper stiffness in a direction in which corner folds form.
2. A sheet of paper as claimed in claim 1 in which the reinforcing watermarks are positive watermarks.
3. A sheet of paper as claimed in claim 1 in which the stripes are straight.
4. A sheet of paper as claimed in claim 1 in which the stripes are undulating.
5. A sheet of paper as claimed in claim 1 in which the stripes of the corner reinforcing watermarks substantially extend at an angle of 45° to the edges of the sheet.
6. A sheet of paper as claimed in claim 1 , in which the stripes have a width in a range of 1 to 2.5 mm.
7. A sheet of paper as claimed in claim 6 in which the width of the stripes lies in a range of 1.5 mm to 2 mm.
8. A sheet of paper as claimed in claim 1 having corner and edge reinforcing watermarks.
9. A sheet of paper as claimed in claim 8 , in which the edge reinforcing watermarks comprise stripes which are substantially parallel to the edges of the sheet.
10. A sheet of paper as claimed in claim 1 in which the reinforcing watermarks are joined by watermark patterns.