Toner replenishing method and unit in image forming apparatus

A toner replenishing unit comprising a toner storing section which forms a fluid mixture of toner and air, toner supplying fluid conveying means for conveying the fluid mixture from said toner storing section, and a toner separating section which is provided away from said toner storing section and separates the fluid mixture into the toner and air, wherein the toner replenishing unit further comprises returning fluid conveying means for returning part of air separated from the toner from said toner separating section to said toner storing section.

A toner replenishing unit comprising a toner storing section which forms a fluid mixture of toner and air, toner supplying fluid conveying means for conveying the fluid mixture from said toner storing section, and a toner separating section which is provided away from said toner storing section and separates the fluid mixture into the toner and air, the toner separating section comprising an introducing chamber where the fluid mixture is introduced and separated into the toner and air, an exhaust chamber which communicates with said introducing chamber so as to discharge air separated from the toner, and a filter which is provided to a filter chamber communicating with said exhaust chamber, wherein said introducing chamber and said exhaust chamber communicate with each other through a meandering path.

An image forming apparatus comprising an image forming section which has a developing unit, a sheet feeding section which is provided below said image forming section, a toner storing section which is arranged below said image forming section and on a side of said sheet feeding section and forms a fluid mixture of toner and air, a toner separating section which is arranged away from said toner storing section and in the vicinity of said developing unit, a first transport pipe which transports the fluid mixture from said toner storing section to said toner separating section, a second transport pipe which returns part of air separated from the toner in said toner separating section to said toner storing section, a fluid mixture conveying pump which is provided midway along said first transport pipe, and a returning air conveying pump which is provided midway along said second transport pipe.