Device for removal of particles from a web of material

A device for removing particles from a surface of a web of material, the device comprising:

• a member made from an electrically non-conducting material, and having an electrostatically chargeable and dischargeable surface which is movable along a path to and from a particle removal area, wherein the particle removal area is configured for interaction between the member and the web of material to transfer particles from the web of material to the charged member surface by electrostatic attraction;
• a charging device arranged along the path of the member surface upstream of the particle removal area, wherein the charging device is configured for charging the member surface;
• and
• a vacuum cleaning device arranged along the path of the member surface downstream of the particle removal area, wherein the vacuum cleaning device is configured to generate a flow of air over the member surface for removal of particles from the member surface, the vacuum cleaning device comprising an ionization device configured for neutralizing the member surface and particles on the member surface,
• wherein the member comprises a hollow member cylinder which is rotatable around an axis, wherein said member surface is an outer surface of the member cylinder and said path is circular;
• and
• the charging device comprises:
• outside the member cylinder, a first charge generating device for generating electrical charges;
• and
• inside the member cylinder, a counter-electrode configured to be in mechanical contact with the inner surface of the member cylinder, wherein the counter-electrode is made at least partly from an electrically conducting material, is configured to be kept at neutral potential or earth potential, and is arranged opposite to the first charge generating device, for directing the electrical charges generated by the first charge generating device to an area of the outer surface of the member cylinder.

A method of removing particles from a surface of a web of material, the method comprising:

• providing a member made from an electrically non-conducting material, and having an electrostatically chargeable and dischargeable surface;
• moving the surface along a path to and from a particle removal area, wherein in the particle removal area the member and the web of material interact with each other to transfer particles from the web of material to the charged member surface by electrostatic attraction;
• upstream of the particle removal area, electrostatically charging the member surface;
• and
• downstream of the particle removal area, generating a flow of air over the member surface for removal of particles from the member surface, while electrically neutralizing the member surface and particles on the member surface,
• wherein the member comprises a hollow member cylinder, wherein said surface is an outer surface of the member cylinder and said path is circular;
• and
• the method further comprises:
• rotating the member cylinder around an axis, and charging the member surface by:
• providing, outside the member cylinder, a first charge generating device for generating electrical charges;
• and
• providing, inside the member cylinder, a counter-electrode configured to be in mechanical contact with the inner surface of the member cylinder, wherein the counter-electrode is made at least partly from an electrically conducting material, is kept at neutral potential or earth potential, and is arranged opposite to the first charge generating device, for directing the electrical charges generated by the first charge generating device to a predetermined area of the outer surface of the member cylinder.