Patent ID: 9594332
Date: 2017-03-14
CPC Classifications: G03G

Claim:
1. A developing device, comprising: a casing configured to contain developer; a developer conveyer disposed in the casing and configured to transport the developer through a developer conveyance passage formed in the casing; and a developer bearer disposed in the casing and configured to bear the developer, wherein at least one of the developer conveyer and the developer conveyance passage has a rough surface repellent to the developer having a surface roughness Ra uniform in a direction in which the developer is transported, the casing comprises a developer collecting compartment configured to collect the developer transported from the developer bearer, a developer supply compartment positioned below the developer collecting compartment and configured such that the developer is supplied from the developer supply compartment to the developer bearer, and a partition separating the developer supply compartment from the developer collecting compartment, the developing device comprises a first developer conveyor disposed in the developer collecting compartment and a second developer conveyor disposed in the developer supply compartment, the partition comprises a plurality of communicating portions formed at both longitudinal ends of the developer collecting compartment and the developer supply compartment such that the developer is circulated between the developer collecting compartment and the developer supply compartment through the communicating portions, and a guide face facing the developer collecting compartment, configured to guide the developer from the developer bearer to the developer collecting compartment, and having the rough surface repellent to the developer, and the surface roughness Ra is greater than 25 nm when measured by a scanning probe microscope in a measurement length of 2 μm, and is smaller than 5 μm when measured by a contact-type surface roughness meter according to ES B0601:′01.