Developer container, developing apparatus, process cartridge, apparatus main body, and image forming apparatus

1. A developing apparatus comprising:

a developer bearing member for bearing developer;

a frame housing the developer;

a stirring member including a sheet-like stirring portion and a rotary shaft to which the stirring portion is attached; and

a first electrode and a second electrode which are used to detect a signal related to an amount of the developer housed in the frame and which are arranged with an interval therebetween, the first electrode and the second electrode being arranged along a wall surface of the frame,

wherein an area between the first electrode and the second electrode is positioned below the rotary shaft of the stirring member, and, as seen in a gravitation direction when the developing apparatus is mounted in an image forming apparatus, a trajectory of rotation around the rotary shaft by the stirring member overlaps the area, the first electrode, and the second electrode.

2. The developing apparatus according to claim 1 , wherein the first electrode and the second electrode are positioned below the rotary shaft of the stirring member.

3. The developing apparatus according to claim 1 , wherein the area is an area including a lowermost position in the frame.

4. The developing apparatus according to claim 1 , wherein the first electrode, the second electrode, and the area are arranged in an order of the second electrode, the area, and the first electrode in a rotational direction of the stirring member below a center of the rotary shaft.

5. The developing apparatus according to claim 1 ,

wherein the frame is divided into a first housing area and a second housing area from a side of an opening toward a distal side,

wherein a first stirring member is rotatably provided in the first housing area,

wherein a second stirring member is rotatably provided in the second housing area,

wherein the first electrode and the second electrode are arranged in the first housing area, and

wherein the developing apparatus further comprises a third electrode and a fourth electrode which are used to detect a signal related to an amount of the developer and which are arranged with an interval therebetween in the second housing area.

6. The developing apparatus according to claim 5 , wherein the second electrode and the third electrode are a single electrode member arranged so as to straddle the first housing area and the second housing area.

7. The developing apparatus according to claim 5 ,

wherein the first electrode is positioned below a rotary shaft of the first stirring member, and

wherein the fourth electrode is positioned below a rotary shaft of the second stirring member.

8. The developing apparatus according to claim 5 ,

wherein the first stirring member comes into contact with a first area between the first electrode and the second electrode in the first housing area due to rotation, and

wherein the second stirring member comes into contact with a second area between the third electrode and the fourth electrode in the second housing area due to rotation.

9. The developing apparatus according to claim 5 , wherein the first housing area and the second housing area are divided by a convex portion that protrudes upward in a vertical direction on the wall surface forming the frame.

10. The developing apparatus according to claim 1 ,

wherein the frame includes an opening, and

wherein a lower end of the opening is positioned above the rotary shaft.

11. The developing apparatus according to claim 1 , further comprising:

a contact portion which is capable of coming into contact with the rotating stirring member and which is capable of coming into contact so as push off developer on the stirring member such that the developer drops at a faster rate than when the developer drops from the stirring member by its own weight.

12. The developing apparatus according to claim 1 ,

wherein a difference between an initial value that is a value of capacitance between the first electrode and the second electrode immediately after start of use of a new image forming apparatus and a value of the capacitance at a predetermined timing is acquired,

wherein a remaining amount of developer in the frame is acquired based on the difference, and

wherein the initial value is a value of the capacitance acquired after the developer in the frame is stirred by the stirring member.

13. The developing apparatus according to claim 12 , wherein the initial value is a maximum value of the capacitance in a case where the capacitance increases after a temporary decrease.

14. The developing apparatus according to claim 12 , wherein the initial value is an average value of maximum values of the capacitance while the stirring member makes one round immediately after the start of use of the new image forming apparatus.

15. The developing apparatus according to claim 12 , wherein the initial value is a value of the capacitance after a developer bearing member that bears developer for developing an electrostatic latent image and the stirring member are driven for a predetermined period of time and is a maximum value of the capacitance while the stirring member makes one round.

16. The developing apparatus according to claim 1 , wherein the sheet-like stirring portion comes into contact with the area due to rotation of the stirring member.

17. A process cartridge that can be detachable from an apparatus main body of an image forming apparatus, the process cartridge comprising:

the developing apparatus according to claim 1 ; and

an image bearing member that bears an electrostatic image to be developed by developer.

18. An image forming apparatus which forms an image on a recording material using developer, the image forming apparatus comprising:

an main body; and

an image forming unit that forms an image on a recording material,

wherein the developing apparatus according to claim 1 is configured to be detachable from an the apparatus main body.