Patent ID: 6081283
Filing Date: 2000-06-27
Classification: B41J

Abstract:
A direct electrostatic printing device including a pigment particle source, a voltage source, a printhead structure, and a control unit, the pigment particle source providing pigment particles, an image receiving member and the printhead structure are moving relative to each other during printing, the image receiving member having a first face and a second face, the printhead structure being placed in between the pigment particle source and the first face of the image receiving member, the voltage source being connected to the pigment particle source and the back electrode thereby creating an electrical field for transport of pigment particles from the pigment particle source toward the first face of the image receiving member, the printhead structure including control electrodes connected to the control unit to thereby selectively open or close apertures through the printhead structure to permit or restrict the transport of pigment particles to thereby enable the formation of a pigment image on the first face of the image receiving member, wherein the control unit controls the control electrodes of the apertures in such a way as to compensate for a difference in behaviour of the individual apertures during transport of pigment particles to thereby enable a percepted uniform printed image density across the apertures for a specific desired image density.