Developing apparatus and image forming apparatus

A developing apparatus comprising:

• a housing that has a pair of wall portions, and a top cover which extends between the pair of wall portions;
• an additional-developer storage portion that is detachably mounted to the housing and stores additional developer to be supplied into the housing;
• a developing roller that is rotatably supported, by the housing, between the pair of wall portions, and that carries developer;
• a developer conveying path that includes a first conveying path which is disposed in the housing so as to be spaced from the developing roller, and in which the developer is conveyed in a first direction, and a second conveying path which is disposed between the developing roller and the first conveying path, in which the developer is conveyed in a second direction opposite to the first direction, and by which the developer is supplied to the developing roller, the developer conveying path having an upper portion defined by the top cover, and allowing the developer to be circulated and conveyed therein;
• a developer reception opening that is formed in the housing so as to oppose a position on a downstream side, in the first direction, of the first conveying path, and that allows the additional developer to be received therethrough and supplied into the developer conveying path;
• a conveying member that is disposed in the first conveying path, is driven to rotate, and conveys the developer in the first direction such that the developer passes by a position where the developer reception opening opposes the first conveying path;
• and
• a conveying capability reduction wall that is disposed downstream of the developer reception opening in the first direction so as to project from the top cover toward the conveying member, and that locally reduces a developer conveying capability, for the developer, of the conveying member, to form an accumulation portion in which the developer is accumulated at a position opposing the developer reception opening.

An image forming apparatus comprising:

• a developing apparatus;
• an image carrier which has a surface on which an electrostatic latent image is formed, and to which developer is supplied from the developing apparatus, and
• a transfer device that transfers an image from the image carrier to a sheet, wherein
• the developing apparatus includes:
• a housing that has a pair of wall portions, and a top cover which extends between the pair of wall portions;
• an additional-developer storage portion that is detachably mounted to the housing and stores additional developer to be supplied into the housing;
• a developing roller that is rotatably supported, by the housing, between the pair of wall portions, and that carries developer;
• a developer conveying path that includes a first conveying path which is disposed in the housing so as to be spaced from the developing roller, and in which the developer is conveyed in a first direction, and a second conveying path which is disposed between the developing roller and the first conveying path, in which the developer is conveyed in a second direction opposite to the first direction, and by which the developer is supplied to the developing roller, the developer conveying path having an upper portion defined by the top cover;
• a divider that is disposed in the housing and that divides the first conveying path and the second conveying path from each other;
• a first communication path disposed between one of the paired wall portions and a corresponding one of end portions of the divider, and a second communication path disposed between the other of the paired wall portions and the other of the end portions of the divider, the first communication path having a function of delivering the developer from the first conveying path to the second conveying path, the second communication path having a function of delivering the developer from the second conveying path to the first conveying path;
• a developer reception opening that is formed in the housing so as to oppose a position on a downstream side, in the first direction, of the first conveying path, and that allows the additional developer to be received therethrough and supplied into the developer conveying path;
• a conveying member that is disposed in the first conveying path, is driven to rotate, and conveys the developer in the first direction such that the developer passes by a position where the developer reception opening opposes the first conveying path;
• a downstream-side conveying capability reduction portion that is disposed, in the conveying member or the housing, downstream of the developer reception opening in the first direction, and that locally reduces a developer conveying capability, for the developer, of the conveying member, to form a first accumulation portion in which the developer is accumulated at a position opposing the developer reception opening;
• and
• an upstream-side conveying capability reduction wall that is disposed upstream of the developer reception opening in the first direction so as to project from the top cover toward the conveying member, and that locally reduces a developer conveying capability, for the developer, of the conveying member, to form a second accumulation portion in which the developer is accumulated upstream of the developer reception opening in the first direction.

An image forming apparatus comprising:

• a developing apparatus;
• an image carrier which has a surface on which an electrostatic latent image is formed, and to which developer is supplied from the developing apparatus, and
• a transfer device that transfers an image from the image carrier to a sheet, wherein
• the developing apparatus includes:
• a housing that has a pair of wall portions, and a top cover which extends between the pair of wall portions;
• an additional-developer storage portion that is detachably mounted to the housing and stores additional developer to be supplied into the housing;
• a developing roller that is rotatably supported, by the housing, between the pair of wall portions, and that carries developer;
• a developer conveying path that includes a first conveying path which is disposed in the housing so as to be spaced from the developing roller, and in which the developer is conveyed in a first direction, and a second conveying path which is disposed between the developing roller and the first conveying path, in which the developer is conveyed in a second direction opposite to the first direction, and by which the developer is supplied to the developing roller, the developer conveying path having an upper portion defined by the top cover, and allowing the developer to be circulated and conveyed therein;
• a developer reception opening that is formed in the housing so as to oppose a position on a downstream side, in the first direction, of the first conveying path, and that allows the additional developer to be received therethrough and supplied into the developer conveying path;
• a conveying member that is disposed in the first conveying path, is driven to rotate, and conveys the developer in the first direction such that the developer passes by a position where the developer reception opening opposes the first conveying path;
• and
• a conveying capability reduction wall that is disposed downstream of the developer reception opening in the first direction so as to project from the top cover toward the conveying member, and that locally reduces a developer conveying capability, for the developer, of the conveying member, to form an accumulation portion in which the developer is accumulated at a position opposing the developer reception opening.