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US 7,003,235 B2Granted
Developing device for suppressing variations in bulk density of developer, and an image forming apparatus including the developing device
AssigneeRicoh Company, Ltd.
InventorsAkira Azami, Takamasa Ozeki
Life of this patent
Estimating the term…
Abstract
A developing device includes a developer including toner having a coloring agent dispersed in a binder resin, and carrier having a core material, and a coating layer covering the core material and containing a binder resin and a powder. A toner density detecting device detects a toner density of the developer by use of a bulk density sensor, and a control device controls the toner density based on a detection result of the toner density detecting device. The toner density is controlled such that ratio (D/h) of an average particle diameter (D) of the powder to a thickness of the coating layer is greater than 1 and less than 10.
Claims20
A developing device, comprising:
- a developer comprising toner including a coloring agent dispersed in a first binder resin, and carrier including a core material, and a coating layer covering the core material and containing a second binder resin and a powder;
- a developer carrier configured to carry and transfer the developer to an image carrier disposed opposite to the developer carrier;
- a developer conveying member disposed opposite to the developer carrier and configured to convey the developer to the developer carrier;
- a toner density detecting device disposed opposite to the developer conveying member and configured to detect a toner density of the developer by use of a bulk density sensor;
- and
- a control device configured to control the toner density based on a detection result of the toner density detecting device, the toner density being controlled to satisfy the following relationship:
- 1<D/h<10,
- where (D) is an average particle diameter of the powder, and (h) is a thickness of the coating layer.
5 more elements
An image forming apparatus, comprising:
- an image carrier configured to carry an image;
- a latent image forming device configured to form a latent image on the image carrier;
- and
- a developing device configured to develop the latent image formed on the image carrier with a two-component developer including toner and carrier, the developing device comprising,
- the two-component developer comprising the toner including a coloring agent dispersed in a first binder resin, and the carrier including a core material, and a coating layer covering the core material and containing a second binder resin and a powder;
- a developing carrier disposed opposite to the image carrier and configured to carry and transfer the developer to the image carrier;
- a developer conveying member disposed opposite to the developer carrier and configured to convey the developer to the developer carrier;
- a toner density detecting device disposed opposite to the developer conveying member and configured to detect a toner density of the developer by use of a bulk density sensor, and
- a control device configured to control the toner density based on a detection result of the toner density detecting device, the toner density being controlled to satisfy the following relationship:
- 1<D/h<10,
- where (D) is an average particle diameter of the powder, and (h) is a thickness of the coating layer.
8 more elements
An image forming method, comprising:
- forming a latent image on an image carrier;
- conveying a two-component developer to a developer carrier from a developer conveying member disposed opposite to the developer carrier, the two-component developer comprising toner including a coloring agent dispersed in a binder resin, and carrier including a core material, and a coating layer covering the core material and containing a binder resin and a powder;
- developing the latent image formed on the image carrier with the developer carried on the developer carrier disposed opposite to the image carrier;
- detecting a toner density of the developer by use of a bulk density sensor disposed opposite to the developer conveying member;
- and
- controlling the toner density based on a detection result of the bulk density sensor, the toner density being controlled to satisfy the following relationship:
- 1<D/h<10,
- where (D) is an average particle diameter of the powder, and (h) is a thickness of the coating layer.
5 more elements
An image forming apparatus, comprising:
- means for carrying an image;
- means for forming a latent image on the means for carrying;
- and
- means for developing the latent image formed on the means for carrying with a two-component developer including toner and carrier, the means for developing comprising,
- the two-component developer comprising the toner including a coloring agent dispersed in a first binder resin, and the carrier including a core material, and a coating layer covering the core material and containing a second binder resin and a powder;
- means for carrying and transferring the developer to the means for carrying, the means for carrying and transferring being disposed opposite to the means for carrying;
- means for conveying the developer to the means for carrying and transferring, the means for conveying being disposed opposite to the means for carrying and transferring;
- means for detecting a toner density of the developer disposed opposite to the means for conveying;
- and
- means for controlling the toner density based on a detection result of the means for detecting, the toner density being controlled to satisfy the following relationship:
- 1<D/h<10,
- where (D) is an average particle diameter of the powder, and (h) is a thickness of the coating layer.
9 more elements
Dependencies are inferred from the claim text.