Toner replenishing device

A developing apparatus for an electrophotographic copying machine, said apparatus comprising a developing roller for developing a latent image on an image retainer with a developer containing toner particles and carrier particles;

• an agitating device for mixing toner particles and carrier particles therein to produce said developer wherein said agitating device feeds said developer to said developing roller;
• and
• a replenisher situated above said agitating means for releasably containing said toner particles, said replenisher having an opening disposed so as to form a space between said developer in said agitating device and said toner particles in said replenisher,
• a feed roller disposed above said opening, said feed roller including a plurality of magnets therein whereby said carrier particles in said agitating device are attracted to form a magnetic brush thereon,
• a preventing member surrounding a part of a lower portion of said roller, said preventing member being separated from said feed roller by a first clearance having a height less than or equal to that of said magnetic brush, said first clearance being sealed by said magnetic brush when said roller is not rotated, whereby said carrier particles are prevented from dropping through said opening between said roller and said replenisher and permitting said toner particles and said carrier particles to drop through said opening as said roller is rotated,
• said feed roller being rotatable in a direction such that a point on its periphery passes said preventing member and then said regulating member.

A device for feeding a developer to a developing apparatus, said developer comprising toner particles and carrier particles, said device comprising

• a replenishing room for receiving said toner particles and said carrier particles,
• an agitation chamber below said replenishing room and adjacent thereto, said chamber adapted to receive said toner particles and said carrier particles from said replenishing room,
• an agitator in said chamber to mix said toner particles and said carrier particles to produce said developer and to convey said developer to a developing means,
• an opening between said replenishing room and said chamber through which said toner particles and said carrier particles drop into said chamber, said opening having a first edge and a second edge,
• a feed roller, adjacent to and disposed above said opening, for feeding said toner particles and said carrier particles through said opening, said feed roller including a plurality of magnets therein whereby said carrier particles are attracted to form a magnetic brush, said feed roller rotatable in a direction such that a point on its periphery passes said first edge and then said second edge, whereby rotation of said feed roller permits said toner particles and said carrier particles to fall through said opening into said chamber,
• preventing means surrounding a part of a lower portion of said feed roller and separated therefrom by a first clearance, for restraining said toner particles and said carrier particles from dropping through a gap between said roller and said opening and permitting said toner particles and said carrier particles to drop through said opening as said roller is rotated,
• a regulator adjacent said second edge and spaced therefrom by a second clearance, said regulator regulating the height of said magnetic brush, and
• a stop means for stopping said feed roller so that none of said magnets is in an open area between said preventing means and said regulator.