Developing device and image forming apparatus
AssigneeSharp Kabushiki Kaisha
InventorYuhsuke YOSHIMOTO
Life of this patent
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Abstract
There are provided a developing device capable of preventing occurrence of image unevenness by releasing a developer residing on a surface of a developing roller reliably, and an image forming apparatus. An angle α formed by a first plane including a position at which a magnetic flux density in a normal direction by a removing pole becomes a maximal value on a surface of the developing sleeve and a rotational axis of a developing sleeve, and a second plane including a first axis of a first rotational shaft section of a first agitating conveyance section and the rotational axis of the developing sleeve 17 is 20° or more and 40° or less.
Claims9
A developing device, comprising:
- a developing roller having a cylindrical-shaped sleeve supported so as to be rotatable around an axis thereof and a magnet roller provided with a plurality of magnetic poles that are fixed in the cylindrical-shaped sleeve, the developing roller carrying a two-component developer including a toner and a carrier on a surface of the cylindrical-shaped sleeve to convey the two-component developer to a developing area facing a photoreceptor on which an electrostatic latent image is formed, the plurality of magnetic poles including a developing magnetic pole for supplying the toner to the photoreceptor in the developing area, and a removing pole disposed on a downstream side from the developing area in a rotational direction of the cylindrical-shaped sleeve, for removing the two-component developer residing on the surface of the cylindrical-shaped sleeve after the toner is supplied to the photoreceptor from the surface of the cylindrical-shaped sleeve;
- a developer supplying member that is disposed vertically below the developing roller and supplies the two-component developer to the surface of the cylindrical-shaped sleeve on an upstream side from the developing area in the rotational direction of the cylindrical-shaped sleeve;
- a collecting conveyance member that is disposed on the downstream side from the developing area in the rotational direction of the cylindrical-shaped sleeve and conveys the two-component developer removed from the surface of the cylindrical-shaped sleeve by the removing pole, the collecting conveyance member having a first rotational shaft section extending along a first axis parallel to a rotational axis of the cylindrical-shaped sleeve and a first spiral blade section attached in a spiral form to the first rotational shaft section, the collecting conveyance member conveying the two-component developer along the first axis by the first spiral blade section when the first rotational shaft section rotates around the first axis;
- and
- a movement regulating member that is disposed on a downstream side from the developer collecting conveyance member in the rotational direction of the cylindrical-shaped sleeve and on an upstream side from the developer supplying member in the rotational direction of the cylindrical-shaped sleeve, and regulates movement of the two-component developer residing on the surface of the cylindrical-shaped sleeve,
- an angle α formed by a first plane including a position at which a magnetic flux density in a normal direction by the removing pole becomes a maximal value on the surface of the cylindrical-shaped sleeve and the rotational axis of the cylindrical-shaped sleeve, and a second plane including the first axis of the first rotational shaft section and the rotational axis of the cylindrical-shaped sleeve being 20° or more and 40° or less.
Dependencies are inferred from the claim text.