The disclosed structure includes a belt-shaped conveying member configured to convey developer. The conveying member includes a partitioning portion, which is a partition for developer contained in a casing with respect to a conveying direction in which the developer is conveyed, wherein, when the developer container is new, a first developer amount which is an amount of the developer contained at an upstream side that is upstream of the partitioning portion in the conveying direction, is larger than a second developer amount which is an amount of the developer contained at a downstream side that is downstream of the partitioning portion in the conveying direction.

A sheet-shaped sealing member to be pulled out from a front side of the sheet-shaped sealing member in a pull-out direction that is a longitudinal direction of the sheet-shaped sealing member includes a sealing portion and a cutout portion. The sealing portion seals a sealed portion. The cutout portion is cut out to be cantilevered with a position different from the sealing portion as a root portion. The cutout portion has a free end as a fixing portion to be removably fixed to the sealed portion or a fixed portion of a housing in which the sheet-shaped sealing member is installed.

An operation guide label is made to perform a display urging a seal member for sealing a toner replenishment port of a toner container received in an image forming apparatus to be pulled out. The image forming apparatus has a first side surface provided with a power switch and a second side surface adjacent to the first side surface and provided with an opening and closing cover for toner container exchange. The seal member has a grasping part which protrudes from a surface of the toner container. The operation guide label includes a first label part adhered to the first side surface so as to cover at least a part of the power switch, a second label part adhered to a predetermined surface part on the side of the opening and closing cover in the image forming apparatus, and a connection part for connecting the both label.

A developing device including a holding body, a supply unit, a filling portion, a closing portion, and a duct portion is provided. The holding body holds a developer. The agitating unit agitates the developer. The supply unit supplies the developer that flows in from the agitating unit to the holding body. The filling portion is provided above the agitating unit and filled with the developer. The closing portion closes a lower portion of the filling portion, and causes the developer to drop from the filling portion into the agitating unit in a case where the closing portion is removed. The duct portion connects a space in the filling portion and a portion above the holding body.

The disclosed structure includes a belt-shaped conveying member configured to convey developer. The conveying member includes a partitioning portion, which is a partition for developer contained in a casing with respect to a conveying direction in which the developer is conveyed, wherein, when the developer container is new, a first developer amount which is an amount of the developer contained at an upstream side that is upstream of the partitioning portion in the conveying direction, is larger than a second developer amount which is an amount of the developer contained at a downstream side that is downstream of the partitioning portion in the conveying direction.

An operation guide label is made to perform a display urging a seal member for sealing a toner replenishment port of a toner container received in an image forming apparatus to be pulled out. The image forming apparatus has a first side surface provided with a power switch and a second side surface adjacent to the first side surface and provided with an opening and closing cover for toner container exchange. The seal member has a grasping part which protrudes from a surface of the toner container. The operation guide label includes a first label part adhered to the first side surface so as to cover at least a part of the power switch, a second label part adhered to a predetermined surface part on the side of the opening and closing cover in the image forming apparatus, and a connection part for connecting the both label.

A developing device detachably mountable to an image forming apparatus includes a developer carrying member and a developer accommodating container including first and second chambers for circulating developer and a supply opening. An openable mechanism maintains a closed state of a discharge opening in the developer accommodating container before initial drive input into the developing device and opens and closes the discharge opening in interrelation with a mounting and demounting operation of the developing device after initial drive of the developing device. The openable mechanism includes a shutter, a spring member for urging the shutter in a closing direction, a sealing sheet for unsealably sealing the discharge opening and for sealing an initial developer in the accommodating container, and a winding-up shaft for winding up the sealing sheet. The sealing sheet is removed from the discharge opening after the initial drive of the developing device.

A developing device includes a developing roller, a developer supply rotator, a removable sheet-shaped member, an upper developing case, and a lower developing case. The developer supply rotator is opposite the developing roller to supply developer to the developing roller. The removable sheet-shaped member separates the developing roller and the developer supply rotator to form a developer pre-storage portion storing the developer in an inner space in which the developer supply rotator is disposed in the developing device. The upper developing case is above the sheet-shaped member to cover the developing roller. The lower developing case is below the sheet-shaped member to form a developing case together with the upper developing case and is divided into a first lower developing case and a second lower developing case. The sheet-shaped member is removably attached directly or indirectly to the first lower developing case and the second lower developing case.