Method and device for cleaning an electrode matrix of an electrographic printer

A device for improving the printing quality and performance of electrographical printers in which a latent electrical charge pattern of electrical signals is produced in a print unit, the print unit having an electrode matrix disposed between a particle carrier and a backing electrode, the electrode matrix comprising a screen or grid of electrodes connected through a controlling device to a voltage source and a plurality of passages which are partly opened and closed electrostatically in response to control signals corresponding to image information applied to the electrode matrix for the controlled transmission of pigment particles of toner to an information carrier which is located between the background electrode and a developer roller, the background electrode and developer roller each being connected to at least one voltage source for producing electrostatic fields therebetween, the device comprising:

• a slotted area in the print unit in close proximity to the electrode matrix;
• and
• means connected to the slotted area for producing a cleaning force to transport the pigment particles toward the developer roller and away from the electrode matrix, wherein the means for producing the cleaning force comprising a bellowed pigment particle container and means for expanding or compressing the container, wherein, when the container is expanded, a stream of air is produced to remove the pigment particles from the electrode matrix.

A device for improving the printing quality and performance of electrographical printers in which a latent electrical charge pattern of electrical signals is produced in a print unit, the print unit having an electrode matrix disposed between a particle carrier and a backing electrode, the electrode matrix comprising a screen or grid of electrodes connected through a controlling device to a voltage source and a plurality of passages which are partly opened and closed electrostatically in response to control signals corresponding to image information applied to the electrode matrix for the controlled transmission of pigment particles of toner to an information carrier which is located between the background electrode and a developer roller, the background electrode and developer roller each being connected to at least one voltage source for producing electrostatic fields therebetween, the device comprising:

• a slotted area in the print unit in close proximity to the electrode matrix;
• and
• means connected to the slotted area for producing a cleaning force to transport the pigment particles toward the developer roller and away from the electrode matrix, wherein the means for producing the cleaning force comprises a magnet disposed within the developer roller, the magnet being movable between a passive position wherein the magnet is spaced from the slotted area and an active position wherein said magnet is at the slotted area, the magnet producing a magnetic field to remove the pigment particles from the electrode matrix.

A device for improving the printing quality and performance of electrographical printers in which a latent electrical charge pattern of electrical signals is produced in a print unit, the print unit having an electrode matrix disposed between a particle carrier and a backing electrode, the electrode matrix comprising a screen or grid of electrodes connected through a controlling device to a voltage source and a plurality of passages which are partly opened and closed electrostatically in response to control signals corresponding to image information applied to the electrode matrix for the controlled transmission of pigment particles of toner to an information carrier which is located between the background electrode and a developer roller, the background electrode and developer roller each being connected to at least one voltage source for producing electrostatic fields therebetween, the device comprising:

• a slotted area in the print unit in close proximity to the electrode matrix;
• and
• means connected to the slotted area for producing a cleaning force to transport the pigment particles toward the developer roller and away from the electrode matrix, wherein the means for producing the cleaning force comprises a magnetic core disposed within the developer roller, the magnetic core having at least one decontamination pole which produces a magnetic field in the slotted area, the magnetic field having an extension which corresponds to an extension of the electrode matrix.