Developing device with a detachably mounted toner cartridge

A developing device comprising a toner cartridge receiver, and a toner cartridge to be mounted detachably on the toner cartridge receiver, wherein

• the toner cartridge includes a container body having a toner discharge opening, a shutter member mounted on the container body so as to be free to reciprocate between a closing position where it covers the toner discharge opening and an opening position where it is displaced from the toner discharge opening, and a flexible band-like sealing member;
• the shutter member is situated at the closing position, and that sealing portion of the sealing member which lies between the container body and the shutter member is bonded strippably to the container body at the peripheral edge of the toner discharge opening, thus sealing the toner discharge opening;
• when the shutter member is forwarded from the closing position to the opening position, the sealing portion of the sealing member is stripped from the container body and displaced from the toner discharge opening to unclose the toner discharge opening, while when the shutter member is returned from the opening position to the closing position, the sealing portion of the sealing member and the shutter member cover the toner discharge opening again;
• by inserting the container body of the toner cartridge to a predetermined position of insertion in a direction perpendicular to the direction of the reciprocation of the shutter member, and then moving the container body to a predetermined position of mounting in the direction of the returning of the shutter member relative to the container body in the toner cartridge, the toner cartridge is mounted on the toner cartridge receiver;
• by moving the container body of the toner cartridge from the position of mounting to the position of insertion in the direction of the forwarding of the shutter member relative to the container body in the toner cartridge, and then withdrawing the container body in a direction perpendicular to the direction of the reciprocation of the shutter member, the toner cartridge is released from the toner cartridge receiver;
• the toner cartridge receiver is provided with a shutter member forwarding means and a shutter member returning means;
• when the toner cartridge is inserted as far as the position of insertion, the shutter member forwarding means is positioned so as to face the rear edge of the shutter member when viewed in the direction of the forwarding of the shutter member relative to the container body, while the shutter member returning means is positioned so as to face the rear edge of the shutter member when viewed in the direction of the returning of the shutter member relative to the container body;
• when the container body is moved from the position of insertion to the position of mounting, the shutter member is inhibited by the shutter member forwarding means from moving as an accompaniment to the container body, and is thus forwarded relative to the container body to unclose the toner discharge opening;
• and when the container body is moved from the position of mounting to the position of insertion, the shutter member is inhibited by the shutter member returning means from moving as an accompaniment to the container body, and is thus returned relative to the container body to cover the toner discharge opening again with the sealing portion of the sealing member and the shutter member.