Method and an apparatus for printing sequential characters

1. A numbering box for carrying out sequential printing of numerical characters, wherein said numbering box comprises at least six numbering wheels with numbers engraved on the peripheral surface thereof, namely a unit wheel, a 10 th wheel, a 100 th wheel, a 1000 th wheel, a 10000 th wheel and a 100000 th wheel, which numbering wheels are provided with combinations of ratchet and groove profiles on side surfaces thereof,

and wherein said numbering wheels are actuated by an actuation lever which cooperates with said combinations of ratchet and groove profiles on the numbering wheels through first and second actuation pawls,

said first actuation pawl being a two-teeth actuation pawl that cooperates with ratchet and groove profiles provided on the right side of the unit wheel and of the 10 th wheel,

said second actuation pawl being a five-teeth actuation pawl that cooperates with ratchet and groove profiles provided on the left side of the 10 th wheel, 100 th wheel, 1000 th wheel, 10000 th wheel and 100000 th wheel.

2. A method for sequential printing of numerical characters on successive sheets each bearing a plurality of locations to be numbered, which locations are arranged in a matrix of maximum rows (mr) and of maximum columns (mc), wherein product mr×mc is a multiple of ten, said method comprising the steps of:

(a) providing mr×mc sequential numbering boxes as defined in claim 1 each having a plurality of numbering wheels;

(b) arranging said numbering boxes in a matrix of maximum rows (mr) and of maximum columns (mc) corresponding to the matrix of locations to be numbered on the sheets, a first of said numbering boxes being located at matrix location (mr ; mc), a second of said numbering boxes being located at matrix location (mr−1 ; mc), and so on until a last one of said numbering boxes is located at matrix location ( 1 ; 1 );

(c) setting the position of the numbering wheels of the numbering boxes to form determined sequences of numerical characters so that adjacent numbering boxes exhibit sequences of numerical characters with a value difference of 100 row wise and a value difference of mr×100 column wise;

(d) printing a first one of a series of hundred sheets with said numbering boxes, thereby printing said sequences of numerical characters on said locations on the sheet;

(e) actuating all said numbering boxes so that all the sequences of numerical characters formed by said numbering wheels are decremented by one;

(f) printing a subsequent sheet with said numbering boxes, thereby printing said sequences of numerical characters decremented by one on said locations on the second sheet;

(g) repeating steps (e) and (f) until hundred sheets have been printed;

(h) resetting the position of the numbering wheels of the numbering boxes, so that the sequences of numerical characters formed by the numbering boxes correspond respectively to the sequences of numerical characters at the time of the printing of the first of the series of hundred sheets at step (d) decremented by a value of mr×mc×100;

(i) repeating steps (d) to (h) for subsequent series of hundred sheets.

3. The method as claimed in claim 2 , wherein each sheet carries a matrix of fifty locations and wherein mr and mc can be selected from any one of the following matrix combinations (mr=5; mc=10), (mr=10; mc=5), (mr=25; mc=2), or (mr=2; mc=25).

4. The method as claimed in claim 3 , wherein mr=10 and mc=5.

5. The method as claimed in claim 2 , wherein each sheet carries a matrix of forty locations and wherein mr and mc can be selected from any one of the following matrix combinations (mr=5; mc=8), (mr=8; mc=5), (mr=10; mc=4), (mr=4; mc=10), (mr=20; mc=2), or (mr=2; mc=20).

6. The method as claimed in claim 5 , wherein mr=8 and mc=5.

7. The method as claimed in claim 2 , wherein each sheet carries a matrix of twenty locations and wherein mr and mc can be selected from any one of the following matrix combinations (mr=2; mc=10), (mr=10; mc=2), (mr=5; mc=4), or (mr=4; mc=5).

8. The method as claimed in claim 7 , wherein mr=10 and mc=2.

9. The method according to claim 2 , wherein said sheets are sheets for the production of banknotes, securities or passports.