| 摘要 |
A method for printing information on a substrate comprising security features is provided, being a Direct Electrostatic Printing (DEP) method, comprising the steps of : i) passing a substrate comprising security features and having thickness T in mu m, in a spacing, having a width L in mu m, between a printhead structure (106) and a back electrode (105), ii) providing, from a toner delivery means (101), a cloud (104) of toner particles in the vicinity of printing apertures (107) in the printhead structure (106), iii) image wise depositing toner particles on the substrate through the printing apertures and iv) fixing the toner particles to the substrate. Preferably L ≥ 1.5T and between the back electrode and the toner delivery means a DC potential difference (DCTB) such that ¦DCTB¦/L ≥ 1.0, where ¦DCTB¦/L is expressed in V/ mu m. <IMAGE>
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