Direct electrostatic printing apparatus having a magnetic brush with a core rotating at high speed
AssigneeAgfa-Gevaert
InventorsGuido Desie, Dirk Broddin
Life of this patent
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Abstract
A DEP device is provided that comprises a printhead structure with control electrodes in combination with printing apertures and a magnetic brush assembly delivering a cloud of toner particles in the vicinity of the printing apertures, wherein the toner particles are, together with magnetically attractable carrier particles part of a multi-component developer further and the magnetic brush comprises a magnetic core rotating at a speed equal to or higher than 500 rpm (rotations per minute) and a sleeve rotating at a speed equal to or lower than 10 rpm (rotations per minute).
Claims5
A DEP device comprising:
- means for creating a flow of charged toner particles from a magnetic brush assembly, carrying a developer with magnetically attractable carrier particles and non-magnetic toner particles, to an image receiving substrate,
- a printhead structure with printing apertures and control electrodes, interposed in said flow of toner particles,
- a voltage source for applying an image-wise adaptable voltage on said control electrodes for image wise modulating said flow of toner particles,
- wherein said magnetic brush assembly has a core equiped with means for rotating said core at a rotational speed equal to or higher than 500 rotations per minute and a sleeve rotatably mounted around said core and equiped with means for rotating said sleeve at a rotational speed equal to or lower than 10 rotations per minute.
A method for direct electrostatic printing comprising the steps of:
- creating a DC potential difference between an image receiving substrate and a magnetic brush assembly assembly having a rotatably mounted core and a sleeve rotatably mounted around said core;
- rotating said core at a rotational speed equal to or higher than 500 rotations per minute and rotating said sleeve at a rotational speed equal to or lower than 10 rotations per minute;
- applying a developer with toner particles and magnetically attractable carrier particles on said magnetic brush assembly;
- creating a flow of toner particles directly from said magnetic brush assembly to said image receiving substrate;
- interposing a printhead structure, having printing apertures and control electrodes around said printing apertures, between said magnetic brush assembly and said substrate,
- applying a voltage to said control electrodes for image wise controlling said flow of toner particles;
- image wise depositing toner particles on said substrate through said printing apertures and
- fixing said toner particles to said substrate.
Dependencies are inferred from the claim text.