Assembling and disassembling methods for developing cartridge

A disassembling method of a cartridge having a developing device, said cartridge being detachably mountable to a main assembly of an image forming apparatus, said method comprising the steps of:

• removing a side cover from a container unit, which comprises a toner frame for accommodating toner and a developing frame connected to the toner frame;
• said step including removing, from the side cover, a first shaft portion of a developing roller supported by the side cover at one longitudinal end thereof and a first shaft portion of a toner-supplying roller at the one longitudinal end of said developing roller, wherein the developing roller is effective to carry the toner to a developing position, and the toner-supplying roller is effective to supply the toner to the developing roller;
• removing a bearing unit from the container unit, said bearing-unit removing step including the step of removing, from the bearing unit, a second shaft portion of the developing roller supported by the bearing unit at the other longitudinal end of said developing roller and a second shaft portion of the toner-supplying roller at the other longitudinal end of said developing roller;
• removing the developing roller from the developing frame after the step of removing the side cover and after the step of removing the bearing unit;
• and
• removing a toner-layer-thickness-regulating member from the developing frame after the step of removing the developing roller, wherein the toner-layer-thickness-regulating member is effective to regulate a thickness of a layer of the toner carried on the developing roller.