Patent ID: 6174048
Filing Date: 2001-01-16
Classification: B41J

Abstract:
A direct electrostatic printing device which prints an image onto an information carrier, the device comprising:a pigment particle source, which provides pigment particles;a voltage source;a control unit;at least one printhead structure having a plurality of apertures through the at least one printhead structure and having control electrodes proximate to the apertures, the control electrodes being coupled to the control unit;a back electrode; andan image receiving member; wherein:the image receiving member and the at least one printhead structure move relative to each other during printing;the image receiving member has a first face and a second face;the at least one printhead structure is positioned between the pigment particle source and the first face of the image receiving member;the voltage source is connected to the pigment particle source and the back electrode to thereby create an electrical field for transport of pigment particles from the pigment particle source toward the first face of the image receiving member;the control electrodes of the at least one printhead structure are responsive to the control unit to thereby selectively open or close the apertures through the at least one printhead structure to permit or restrict the transport of pigment particles to form a pigment image on the first face of the image receiving member nominally aligned with a dot matrix; andthe control unit controls the transport of pigment particles by controllably applying time displacements to the selective opening and closing of apertures to thereby adjust a dot position from the dot matrix in a direction mainly parallel to the direction of the relative movement between the image receiving member and the at least one printhead structure, so that edges of image features not aligned with the dot matrix of the image printed onto the information carrier appear smoother.