Development device, process cartridge and image forming apparatus

A development device developing a latent image on an image bearing member of an image forming apparatus, the development device comprising:

• an electrostatic conveyance device having an electrostatic conveyance surface and configured to move powder on the electrostatic conveyance surface by a phase-shifting electric field to a development area of the electrostatic conveyance device opposing the image bearing member to develop the latent image on the image bearing member;
• a supply device configured to supply the powder to the electrostatic conveyance device from a powder accommodation part accommodating the powder;
• and
• a collection device configured to collect the powder on the electrostatic conveyance surface of the electrostatic conveyance device passed the development area of the electrostatic conveyance device without contributing to development in the development area, and including
• a collection member configured to collect the powder on the electrostatic conveyance surface of the electrostatic conveyance device passed the development area of the electrostatic conveyance member by applying bias voltage to the collection member before the powder passed the development area of the electrostatic conveyance device reaches the development area again.

A process cartridge for an image forming apparatus, comprising:

• an image forming mechanism including at least one of an image bearing member for bearing an image, a charging device for charging a surface of the image bearing member, and a cleaning device for cleaning the surface of the image bearing member;
• and
• a development device configured to develop the image on the image bearing member, the development device including
• an electrostatic conveyance device having an electrostatic conveyance surface and configured to move powder on the electrostatic conveyance surface by a phase-shifting electric field to a development area of the electrostatic conveyance device opposing the image bearing member to develop the latent image on the image bearing member,
• a supply device configured to supply the powder to the electrostatic conveyance device from a powder accommodation part accommodating the powder, and
• a collection device configured to collect the powder on the electrostatic conveyance surface of the electrostatic conveyance device passed the development area of the electrostatic conveyance device without contributing to development in the development area, the collection device including a collection member for collecting the powder on the electrostatic conveyance surface of the electrostatic conveyance device passed the development area of the electrostatic conveyance device by applying bias voltage to the collection member before the powder passed the development area of the electrostatic conveyance device reaches the development area again.

An image forming apparatus, comprising:

• a process cartridge including
• a development device developing a latent image on an image bearing member of an image forming apparatus, the development device comprising:
• an electrostatic conveyance device having an electrostatic conveyance surface and configured to move toner particles on the electrostatic conveyance surface in a toner conveyance direction by a phase-shifting electric field, the electrostatic conveyance surface having an upstream side end where the phase-shifting electric field starts and a downstream side end where the phase-shifting electric field ends;
• a supply device arranged to oppose the upstream side end of the electrostatic conveyance surface of the electrostatic conveyance device to supply the toner particles onto the electrostatic conveyance surface of the electrostatic conveyance device, the toner particles supplied by the supply device onto the electrostatic conveyance surface of the electrostatic conveyance device being moved on the electrostatic conveyance surface by the phase-shifting electric field to a development area of the electrostatic conveyance device opposing the image bearing member for development of the latent image on the latent image bearing member;
• and
• a collection device arranged to oppose the downstream side end of the electrostatic conveyance surface of the electrostatic conveyance device and configured to collect the toner particles moved on the electrostatic conveyance surface to a downstream side of the development area of the electrostatic conveyance device in the toner conveyance direction without contributing to the development of the latent image in the development area.

An image forming apparatus, comprising:

• a development device developing a latent image on an image bearing member of an image forming apparatus, the development device including
• an electrostatic conveyance device having an electrostatic conveyance surface and configured to move powder on the electrostatic conveyance surface by a phase-shifting electric field to a development area of the electrostatic conveyance device opposing the image bearing member to develop the latent image on the image bearing member,
• a supply device configured to supply the powder to the electrostatic conveyance device from a powder accommodation part accommodating the powder, and
• a collection device configured to collect the powder on the electrostatic conveyance surface of the electrostatic conveyance device passed the development area of the electrostatic conveyance device without contributing to development in the development area, and including
• a collection member configured to collect the powder on the electrostatic conveyance surface of the electrostatic conveyance device passed the development area of the electrostatic conveyance member by applying bias voltage to the collection member before the powder passed the development area of the electrostatic conveyance device reaches the development area again.

A color image forming apparatus, comprising:

• a plurality of process cartridges corresponding to a plurality of elementary colors, each one of the plurality of process cartridges including
• an image forming mechanism including at least one of an image bearing member for bearing an image, a charging device for charging a surface of the image bearing member, and a cleaning device for cleaning the surface of the image bearing member, and
• a development device configured to develop the image on the image bearing member, the development device including
• an electrostatic conveyance device having an electrostatic conveyance surface and configured to move powder on the electrostatic conveyance surface by a phase-shifting electric field to a development area of the electrostatic conveyance device opposing the image bearing member to develop the latent image on the image bearing member,
• a supply device configured to supply the powder to the electrostatic conveyance device from a powder accommodation part accommodating the powder, and
• a collection device configured to collect the powder on the electrostatic conveyance surface of the electrostatic conveyance device passed the development area of the electrostatic conveyance device without contributing to development in the development area, the collection device including a collection member for collecting the powder on the electrostatic conveyance surface of the electrostatic conveyance device passed the development area of the electrostatic conveyance device by applying bias voltage to the collection member before the powder passed the development area of the electrostatic conveyance device reaches the development area again.