Powder filling processes

A method of manufacturing an elongate carrier with microdepressions containing finely divided powder said process comprising:

• providing a web comprising a plurality of microdepressions in a major surface of the web, said microdepressions having a depth of about 5 to 500 microns but less than the thickness of the web and an opening at the surface of the web of about 10 to 500 microns in width,
• continuously feeding the web to and through a powder filling stage
• at the powder filling stage, filling the powder into said microdepressions on the surface of the web using a driven roller, wherein said roller is rotating about an axis generally transverse to said direction of web movement, while the surface speed of the roller and the web speed are different and wherein the roller and web are positioned relative to one another, such that between the upper surface of the web and the outer surface of the roller there is a gap;
• removing from said surface of the web excess powder not filled within the microdepressions and remaining on areas of the surface between the depressions;
• and optionally slitting and/or cutting the web in predetermined widths and/or predetermined lengths
• wherein the powder is fed either onto the web upstream of the roller of the powder filling stage or to the roller of the powder filling stage;
• and
• wherein the method further comprises sensing accumulation of powder on the roller and/or on the web upstream of the roller and in response to said sensing automatically controlling the powder feed.