Developing apparatus

A developing apparatus for electrophotographic machines comprising:

• a magnetic roller including a magnet with a main polarity and a supplementary polarity and a rotating sleeve disposed around said magnet,
• said main polarity opposing a photosensitive drum and said supplementary polarity disposed upstream of said main polarity in the direction of rotation of said sleeve,
• said main polarity and said supplementary polarity being opposite in polarity to each other, said magnetic roller conveying a developer along the surface of said sleeve forming a magnetic brush on said sleeve at said supplementary polarity as said sleeve rotates,
• a developer-regulating means that is disposed upstream of said supplementary polarity for regulating the amount of developer conveyed on the surface of said sleeve, and
• a guiding means having a first surface area disposed downstream of said developer-regulating means in the direction of rotation of said sleeve extending downstream of said supplementary polarity, and a second surface area successively disposed downstream of said first surface area;
• wherein said first surface area of said guide means is spaced from the surface of said sleeve to such an extent as to allow the magnetic brush to come into contact with said first surface area,
• said second surface area being closer to the surface of said sleeve than said first surface area, and
• said first surface area, the surface of said sleeve, said second surface area and said developer-regulator means forming a hollow within which said magnetic brush is formed, said hollow and said magnetic brush acting to prevent the escape of excess toner forced past said developer-regulator means.