Developer agitating/conveying device

A developer agitating/conveying device for use with an image processing system, said developer agitating/conveying device comprising:

• a housing,
• an upstream-side partition wall and a downstream side partition wall disposed at spaced apart locations within the housing, each partition wall having a developer transfer port at the central portion thereof,
• a first agitating/conveying member disposed between the upstream-side partition wall and the downstream-side partition wall for conveying developer from opposite end portions of the housing toward the central portion thereof, the first agitating/conveying member having a first helical blade and a second helical blade helically wound in directions opposite to each other,
• a second agitating/conveying member disposed along the downstream side of the downstream-side partition wall for conveying the developer from the central portion of the housing toward the opposite end portions thereof, the second agitating/conveying member having a first helical blade and a second helical blade helically wound in directions opposite to each other, and
• a third agitating/conveying member disposed along the upstream side of the upstream-side partition wall for conveying the developer from the central portion of the housing toward the opposite end portions thereof, the third agitating/conveying member having a first helical blade and a second helical blade helically wound in directions opposite to each other,
• the first and second helical blades on the first agitating/conveying member having their respective inner end half pitches overlap with a phase angle of 180 degrees relative to each other so as not to intersect each other.