Developing apparatus, image formation apparatus, and process cartridge

A developing apparatus, comprising:

• a developer carrier, having a magnetic field generating device therein, for carrying a developer containing a toner and a magnetic carrier and transferring the developer to move on a surface of the developer carrier;
• a developer regulating unit, for regulating an amount of the developer that is carried on the developer carrier and transferred towards a developing area;
• a developer container, for containing the developer that is regulated by the developer regulating unit and transferred towards a developing area;
• a toner container, having a toner supply gate facing a surface of the developer carrier at a position adjacent to an upstream side of a developer transfer direction in the developer container;
• an initial developer case, for containing a non-used initial developer that is transferred to the developer container;
• a sealing material, for sealing an initial developer input opening installed on one side of the initial developer case, and capable of being stripped off along a central axis line of the developer carrier;
• wherein by moving the developer when the developer is transferred on the developer carrier, the toner in the toner container is taken into the developer according to a toner concentration of the developer on the developer carrier;
• wherein at least the initial developer case is removable from an image forming device that the developing apparatus is installed in;
• and
• wherein a plurality of partitions are formed inside the initial developer case so that a plurality of partition spaces are divided along the central axis line of the developer carrier inside the initial developer case, and wherein based on the initial developer input opening, a partition surface facing to the partition space of each partition is tilted to one end of the central axis line of the developer carrier with respect to an imaginary plane perpendicular to the central axis line of the developer carrier such that movement of the initial developer is reduced when the initial developer case is tilted to strip off the sealing material.