Patent ID: 8744319

Claim:
A developing device comprising: a developer tank for containing a two-component developer; a partition for dividing an internal space of the developer tank; a first developer conveyance path and a second developer conveyance path which are separated by the partition and arranged in parallel for conveying and circulating the two-component developer in pairs, a first conveyance member provided in the first developer conveyance path in a freely rotatable manner for conveying the two-component developer in one direction, the first conveyance member having: a first rotation axis; a first helical blade fixed to the first rotation axis; and a first passive gear provided to an end of the first rotation axis extended out of the developer tank; a second conveyance member provided in the second developer conveyance path in a freely rotatable manner for conveying the two-component developer in one direction, the second conveyance member having: a second rotation axis; a second helical blade fixed to the second rotation axis; and a second passive gear provided to an end of the second rotation axis extended out of the developer tank; a first communicating path for guiding the two-component developer in the first developer conveyance path to the second developer conveyance path; a second communicating path for guiding the two-component developer in the second developer conveyance path to the first developer conveyance path; a developing roller for bearing and supplying the two-component developer in the second developer conveyance path to a photoconductor drum; and a rotation axis bending prevention belt provided so as to be put around with tension applied the first rotation axis and the second rotation axis outside the developer tank.