Developing apparatus having a sealing sheet and unsealing mechanism

A developing apparatus, comprising:

• a developer bearing member bearing and feeding developer including toner and carrier in order to develop an electrostatic image formed on an image bearing member;
• a developing container including a first chamber and a second chamber partitioned by a partition wall from the first chamber, and configured to contain the developer to be supplied to the developer bearing member;
• a first communication portion configured to permit movement of the developer from the first chamber to the second chamber;
• a second communication portion configured to permit movement of the developer from the second chamber to the first chamber;
• a first feeding screw arranged in the first chamber and feeding the developer in a first direction from the second communication portion toward the first communication portion;
• a second feeding screw arranged in the second chamber and including a first blade portion feeding the developer in a second direction from the first communication portion to the second communication portion, a second blade portion arranged downstream of the first blade portion in the second direction and feeding the developer in the first direction to deliver the developer through the second communication portion to the first chamber, and a third blade portion arranged downstream of the second blade portion in the second direction feeding the developer in the second direction;
• a developer replenishing portion configured to replenish replenishment developer to the developing container;
• a developer discharging portion configured to discharge a part of the developer contained in the developing container as the replenishment developer is replenished to the developing container by the developer replenishing portion;
• a sealing sheet arranged upstream of the developer discharging portion in the second direction and sealing initial developer contained in the developing container;
• and
• an unsealing mechanism unsealing the sealing sheet sealing the initial developer,
• wherein the sealing sheet is arranged downstream of the second blade portion and upstream of the third blade portion in the second direction.