Developer cartridge, developing device and image forming apparatus

1. A developer cartridge comprising:

a storing portion that stores developer and has an opening;

a shutter member that opens and closes said opening, the shutter member having a groove; and

a seal member that is wrapped in the groove and seals between said shutter member and said storing portion, said seal member having an elongated shape, and including two end portions and a main part formed therebetween in a longitudinal direction thereof, the end potions facing each other, each end portion having a tip end, and a root end connected to said main part, said tip end and said root end being adjacent to each other in the longitudinal direction, a width of said tip end being smaller than a width of said main part and larger than a width of said root end, a sum of the width of said tip end and the width of said root end is not smaller than a width of said groove.

2. The developer cartridge according to claim 1 , wherein

each end portion of said seal member has a concave portion on one side of said seal member in a width direction of said seal member, said concave portion being disposed on said root end side of said end portion, and

at least one angled portion is provided on said concave portion.

3. The developer cartridge according to claim 1 , wherein, in the longitudinal direction of said seal member, a length L 1 of said concave portion of said end portion and a distance L 2 from a tip end edge of said end portion to said concave portion satisfy the relationship: L 1 >L 2 .

4. A developer cartridge, comprising:

a storing portion that stores developer and has an opening;

a shutter member that opens and closes said opening; and

a seal member that seals between said shutter member and said storing portion, said seal member having an elongated shape, and including two end portions and a main part formed therebetween in a longitudinal direction thereof, the end potions facing each other, each end portion having a tip end, and a root end connected to said main part, said tip end and said root end being adjacent to each other in the longitudinal direction, a width of said tip end being smaller than a width of said main part and larger than a width of said root end, wherein

each end portion of said seal member has an inclined end edge which is inclined with respect to said longitudinal direction of said seal member.

5. The developer cartridge according to claim 4 , wherein said inclined end edge extends from said root end to said tip end, and has an inclination such that said width of said tip end is larger than said width of said root end.

6. The developer cartridge according to claim 4 , wherein

said shutter member has a groove for winding said seal member, and

in a width direction of said seal member, a width L 3 of said groove, a width L 6 of said end portion at a root end thereof, and a width L 7 of said end portion at a tip end thereof satisfy the relationship:

L 3≦( L 6+L7).

7. The developer cartridge according to claim 1 , wherein said seal member is a band-shaped member.

8. The developer cartridge according to claim 1 , wherein said opening is an opening through which said developer stored in said storing portion is taken outside.

9. The developer cartridge according to claim 1 , wherein

said shutter member opens and closes said opening from inside of said storing portion, and

said seal member is provided on an outer circumferential surface of said shutter member so as to seal between said outer circumferential surface of said shutter member and an inner circumferential surface of said storing portion.

10. A developing device using said developer cartridge according to claim 1 .

11. An image forming apparatus including said developing device according to claim 10 .

12. The developer cartridge of claim 1 , wherein a side edge of one end portion of said seal member faces a side edge of the other end portion of said seal member.

13. The developer cartridge of claim 9 , wherein

said seal member is wounded around said shutter member in a direction in which said seal member is movable to open and close said opening, and

both the tip end and the root end of each of said end portions of said seal member extend substantially perpendicular to said direction.

14. The developer cartridge of claim 4 , wherein said seal member is of a band shape.

15. The developer cartridge of claim 4 , wherein said opening is an opening through which said developer stored in said storing portion is taken out.

16. The developer cartridge of claim 4 , wherein

said shutter member opens and closes said opening from an inside of said storing portion; and

said seal member is provided on an outer circumferential surface of said shutter member to seal between said outer circumferential surface of said shutter member and an inner circumferential surface of said storing portion.

17. The developer cartridge according to claim 16 , wherein

said seal member is wound around said shutter member in a direction in which said seal member is movable to open and close said opening, and

both the tip end and the root end of each of said end portions of said seal member extend substantially perpendicular to said direction.

18. The developer cartridge according to claim 4 , wherein a side edge of one end portion of said seal member faces a side edge of the other end portion of said seal member.

19. The developer cartridge according to claim 4 , wherein said inclined end edges of said end portions of said seal member face each other.

20. The developer cartridge according to claim 19 , wherein said inclined end edge extends from said root end to said tip end, and has an inclination in a manner that said width of said tip end is larger than said with of said root end.

21. A developing device using said developer cartridge according to claim 4 .

22. An image forming apparatus including said developing device according to claim 21 .