Abstract: An image forming apparatus includes a developer bearing member configured to bear a developer to develop a latent image, a developer regulating member configured to regulate an amount of the developer carried on the bearing member, a voltage application unit that can apply a plurality of direct current voltages of different values between the bearing member and the regulating member, and a current detection unit that can detect a plurality of direct currents of different values flowing in the regulating member when the voltage application unit applies the plurality of direct current voltages, wherein the image forming apparatus sets a direct current voltage value Vb applied by the voltage application unit when developing the latent image, so that the following expression is satisfied: |Vb|>|Vbmin|, where Vbmin indicates a direct current voltage value when the direct current detected by the current detection unit is a minimum value.

Abstract: An image forming apparatus includes a developer bearing member configured to bear a developer to develop a latent image, a developer regulating member configured to regulate an amount of the developer carried on the bearing member, a voltage application unit that can apply a plurality of direct current voltages of different values between the bearing member and the regulating member, and a current detection unit that can detect a plurality of direct currents of different values flowing in the regulating member when the voltage application unit applies the plurality of direct current voltages, wherein the image forming apparatus sets a direct current voltage value Vb applied by the voltage application unit when developing the latent image, so that the following expression is satisfied: |Vb|>|Vbmin|, where Vbmin indicates a direct current voltage value when the direct current detected by the current detection unit is a minimum value.

Abstract: An image forming apparatus includes an image bearing member; a developer carrying member, contactable to the image bearing member, for carrying a developer to a developing position to develop an electrostatic image formed on the image bearing member with the developer; a supplying member for supplying the developer to the developer carrying member, wherein a peripheral speed of the developer carrying member is not less than 1.05 times and not more than 1.20 times a peripheral speed of the image bearing member, and an arithmetic average roughness Ra is not less than 0.20 times and not more than 0.33 times a volume average particle size of the developer, wherein a potential applied to the supplying member is different from a potential applied to the developer carrying member toward a larger potential of a regular charge polarity of the developer.

Abstract: An amount-of-developer regulating apparatus configured to restrict the amount of developer carried on a developer bearing member. The amount-of-developer regulating apparatus includes a flexible developer amount regulation member having a contact portion configured to contact with a developer bearing member, and first and second holding portions configured to hold the developer amount regulation member and to contact with the developer amount regulation member at further upstream and further downstream in a direction where the developer bearing member is rotationally moved than the contact portion. With a pressure distribution of the contact portion as to the developer bearing member, there are a plurality of local maximum values in the direction where the developer bearing member is rotationally moved. Thus, the apparatus can be reduced in size, and also image concentration unevenness after long-term use can be prevented.

Abstract: An image forming apparatus includes an image bearing member; a developer carrying member, contactable to the image bearing member, for carrying a developer to a developing position to develop an electrostatic image formed on the image bearing member with the developer; a supplying member for supplying the developer to the developer carrying member, wherein a peripheral speed of the developer carrying member is not less than 1.05 times and not more than 1.20 times a peripheral speed of the image bearing member, and an arithmetic average roughness Ra is not less than 0.20 times and not more than 0.33 times a volume average particle size of the developer, wherein a potential applied to the supplying member is different from a potential applied to the developer carrying member toward a larger potential of a regular charge polarity of the developer.

Abstract: A developing apparatus has a developer carrying member carrying a developer thereon, a developer supplying member for supplying the developer to the developer carrying member, and a scraping member for contacting the developer carrying member upstream of the closest position between the developer carrying member and the developer supplying member with respect to the movement direction of the developer carrying member to thereby scrape off the developer from the developer carrying member. There is formed a developer supplying portion surrounded by the scraping member, the developer carrying member and the developer supplying member for supplying the developer from the developer supplying member to the developer carrying member, and the developer scraped off by the scraping member is conveyed to a collecting passage differing from the closest position.

Abstract: An amount-of-developer regulating apparatus configured to restrict the amount of developer carried on a developer bearing member. The amount-of-developer regulating apparatus includes a flexible developer amount regulation member having a contact portion configured to contact with a developer bearing member, and first and second holding portions configured to hold the developer amount regulation member and to contact with the developer amount regulation member at further upstream and further downstream in a direction where the developer bearing member is rotationally moved than the contact portion. With a pressure distribution of the contact portion as to the developer bearing member, there are a plurality of local maximum values in the direction where the developer bearing member is rotationally moved. Thus, the apparatus can be reduced in size, and also image concentration unevenness after long-term use can be prevented.

Abstract: An amount-of-developer regulating apparatus configured to restrict the amount of developer carried on a developer bearing member. The amount-of-developer regulating apparatus includes a flexible developer amount regulation member having a contact portion configured to contact with a developer bearing member, and first and second holding portions configured to hold the developer amount regulation member and to contact with the developer amount regulation member at further upstream and further downstream in a direction where the developer bearing member is rotationally moved than the contact portion. With a pressure distribution of the contact portion as to the developer bearing member, there are a plurality of local maximum values in the direction where the developer bearing member is rotationally moved. Thus, the apparatus can be reduced in size, and also image concentration unevenness after long-term use can be prevented.

Abstract: An image forming apparatus includes an image bearing member; a developer carrying member, contactable to the image bearing member, for carrying a developer to a developing position to develop an electrostatic image formed on the image bearing member with the developer; a supplying member for supplying the developer to the developer carrying member, wherein a peripheral speed of the developer carrying member is not less than 1.05 times and not more than 1.20 times a peripheral speed of the image bearing member, and an arithmetic average roughness Ra is not less than 0.20 times and not more than 0.33 times a volume average particle size of the developer, wherein a potential applied to the supplying member is different from a potential applied to the developer carrying member toward a larger potential of a regular charge polarity of the developer.

Abstract: A developing apparatus in which a toner has a volume-average particle diameter R that is in a range of 4.0 ?m?R?6.2 ?m, a developing roller has an arithmetic mean roughness Ra (?m) that is not more than 0.10 times the volume-average particle diameter R of the toner, a voltage applied to a supply roller is of negative polarity, that is, a normal charging polarity of the toner, triboelectrification polarity of the supply roller with respect to the toner is negative, that is, of the normal charging polarity of the toner, and an abutment width S in which the developing roller and the supply roller abut each other is in a range of 2.5 mm?S?5.5 mm.

Abstract: An image forming apparatus is provided, which controls an appropriate developer amount for a desired image so that an image defect such as an unclear font or a white area is prevented, resulting in a stable image formation for a long term. A developer regulating member has a resistance value varying depending on a voltage to be applied. A control device changes over the voltage to be applied to the developer regulating member during the image formation according to image information and changes a potential difference between the developer carrying member and the developer regulating member.

Abstract: An image forming apparatus includes a developer bearing member configured to bear a developer to develop a latent image, a developer regulating member configured to regulate an amount of the developer carried on the bearing member, a voltage application unit that can apply a plurality of direct current voltages of different values between the bearing member and the regulating member, and a current detection unit that can detect a plurality of direct currents of different values flowing in the regulating member when the voltage application unit applies the plurality of direct current voltages, wherein the image forming apparatus sets a direct current voltage value Vb applied by the voltage application unit when developing the latent image, so that the following expression is satisfied: |Vb|>|Vbmin|, where Vbmin indicates a direct current voltage value when the direct current detected by the current detection unit is a minimum value.

Abstract: A developing apparatus has a developer carrying member carrying a developer thereon, a developer supplying member for supplying the developer to the developer carrying member, and a scraping member for contacting the developer carrying member upstream of the closest position between the developer carrying member and the developer supplying member with respect to the movement direction of the developer carrying member to thereby scrape off the developer from the developer carrying member. There is formed a developer supplying portion surrounded by the scraping member, the developer carrying member and the developer supplying member for supplying the developer from the developer supplying member to the developer carrying member, and the developer scraped off by the scraping member is conveyed to a collecting passage differing from the closest position.

Abstract: A developing apparatus has a developer carrying member carrying a developer thereon, a developer supplying member for supplying the developer to the developer carrying member, and a scraping member for contacting the developer carrying member upstream of the closest position between the developer carrying member and the developer supplying member with respect to the movement direction of the developer carrying member to thereby scrape off the developer from the developer carrying member. There is formed a developer supplying portion surrounded by the scraping member, the developer carrying member and the developer supplying member for supplying the developer from the developer supplying member to the developer carrying member, and the developer scraped off by the scraping member is conveyed to a collecting passage differing from the closest position.

Abstract: A developing apparatus in which a toner has a volume-average particle diameter R that is in a range of 4.0 ?m?R?6.2 ?m, a developing roller has an arithmetic mean roughness Ra (?m) that is not more than 0.10 times the volume-average particle diameter R of the toner, a voltage applied to a supply roller is of negative polarity, that is, a normal charging polarity of the toner, triboelectrification polarity of the supply roller with respect to the toner is negative, that is, of the normal charging polarity of the toner, and an abutment width S in which the developing roller and the supply roller abut each other is in a range of 2.5 mm?S?5.5 mm.

Abstract: An image forming apparatus is provided, which controls an appropriate developer amount for a desired image so that an image defect such as an unclear font or a white area is prevented, resulting in a stable image formation for a long term. A developer regulating member has a resistance value varying depending on a voltage to be applied. A control device changes over the voltage to be applied to the developer regulating member during the image formation according to image information and changes a potential difference between the developer carrying member and the developer regulating member.

Abstract: An amount-of-developer regulating apparatus configured to restrict the amount of developer carried on a developer bearing member. The amount-of-developer regulating apparatus includes a flexible developer amount regulation member having a contact portion configured to contact with a developer bearing member, and first and second holding portions configured to hold the developer amount regulation member and to contact with the developer amount regulation member at further upstream and further downstream in a direction where the developer bearing member is rotationally moved than the contact portion. With a pressure distribution of the contact portion as to the developer bearing member, there are a plurality of local maximum values in the direction where the developer bearing member is rotationally moved. Thus, the apparatus can be reduced in size, and also image concentration unevenness after long-term use can be prevented.

Abstract: An image forming apparatus includes an image bearing member; a developer carrying member, contactable to the image bearing member, for carrying a developer to a developing position to develop an electrostatic image formed on the image bearing member with the developer; a supplying member for supplying the developer to the developer carrying member, wherein a peripheral speed of the developer carrying member is not less than 1.05 times and not more than 1.20 times a peripheral speed of the image bearing member, and an arithmetic average roughness Ra is not less than 0.20 times and not more than 0.33 times a volume average particle size of the developer, wherein a potential applied to the supplying member is different from a potential applied to the developer carrying member toward a larger potential of a regular charge polarity of the developer.

Abstract: A developing apparatus has a developer carrying member carrying a developer thereon, a developer supplying member for supplying the developer to the developer carrying member, and a scraping member for contacting with the developer carrying member upstream of the closest position between the developer carrying member and the developer supplying member with respect to the movement direction of the developer carrying member to thereby scrape off the developer from the developer carrying member, wherein there is formed a developer supplying portion surrounded by the scraping member, the developer carrying member and the developer supplying member for supplying the developer from the developer supplying member to the developer carrying member, and the developer scraped off by the scraping member is conveyed to a collecting passage differing from the closest position.

Abstract: An image forming apparatus, including: an image bearing member on a surface of which an electrostatic latent image is formed; a developing device which contains a developer and which has a rotatable developer carrying member, which abuts against the surface of the image bearing member, and a storage device storing information on image formation history, the developing device being adapted to visualize the electrostatic latent image on the surface of the image bearing member as the developer carrying member carries the developer to the electrostatic latent image; a moving mechanism which moves the developing device to one of a first position where development is performed and a second position where development is not performed; and a control device which controls, based upon the information on image formation history stored in the storage device, an operation for giving a charge to the developer according to a lapsed time from a finish time of image formation, in a state in which the developing device is move