Toner dispersing mechanism, developing device including the toner dispersing mechanism, and image forming apparatus

1. A toner dispersing mechanism, comprising;

a housing arranged between a toner storage container and a developing device, the housing having a toner filling port communicating with toner storage container, and a toner discharge port communicating with the developing device;

a toner dispersing member including

a rotary shaft rotatably supported in the housing, and

a large number of dispersing protrusions, made of an elastic material and formed on an outer peripheral surface of the rotary shaft, for dispersing a lump of toner to come into contact with the large number of dispersing protrusions by rotating the toner dispersing member about the rotary shaft; and

a projecting portion formed continuously at least at a part of an inner wall surface in a longitudinal direction of the housing, the large number of dispersing protrusions facing the inner wall surface part and coming into contact with the projecting portion,

wherein toner replenished from the toner storage container is dispersed and discharged into the developing device,

wherein the large number of dispersing protrusions are formed by wrapping a flexible film member around the outer peripheral surface of the rotary shaft,

wherein the flexible film member includes a large number of cuts formed on one side thereof, and

wherein the cuts are directed outward.

2. A toner dispersing mechanism according to claim 1 , wherein the projecting portion is formed in a vicinity of a downstream side with respect to an opening edge of the toner discharge port in a rotational direction of the toner dispersing member.

3. A toner dispersing mechanism according to claim 1 , further comprising a protrusion projecting to an upstream side in a rotational direction of the toner dispersing member, the protrusion being formed at an end portion of the projecting portion on the upstream side in the rotational direction of the toner dispersing member.

4. A toner dispersing mechanism according to claim 3 , wherein a distance from the inner wall surface of the housing and the protrusion is 50% or more of a distance from the inner wall surface of the housing to the outer peripheral surface of the rotary shaft.

5. A toner dispersing mechanism according to claim 1 ,

wherein an opening width of the toner discharge port in a longitudinal direction of the toner dispersing member is set to be larger than an opening width of the toner filling port, and

wherein the toner dispersing member disperses toner injected from the toner filling port into the housing and discharges the toner from substantially an entire region of the toner discharge port.

6. A toner dispersing mechanism according to claim 1 ,

wherein the dispersing protrusions are fixed while being inclined with respect to an axial direction of the rotary shaft, and

wherein a projection length of each of the dispersing protrusions with respect to the rotary shaft is larger than a pitch between the dispersing protrusions in a direction of the rotary shaft.

7. A toner dispersing mechanism according to claim 6 , wherein the dispersing protrusions are helically arranged with respect to the rotary shaft.

8. A toner dispersing mechanism according to claim 1 , wherein the toner dispersing member further comprises a first support member for supporting the large number of dispersing protrusions at a predetermined angle with respect to the outer peripheral surface of the rotary shaft.

9. A toner dispersing mechanism according to claim 8 ,

wherein the first support member comprises a plurality of first support members annularly provided at a predetermined pitch around the outer peripheral surface of the rotary shaft, and

wherein the dispersing protrusions are formed of a plurality of fan-like film members each including a large number of cuts from an outer edge to an inner edge and wrapped around the outer peripheral surface of the rotary shaft respectively along the plurality of first support members, the fan-like film members each having an inner peripheral side free from the cuts and serving as a fixation portion.

10. A toner dispersing mechanism according to claim 8 ,

wherein the first support member is helically provided at a predetermined pitch around the outer peripheral surface of the rotary shaft, and

wherein the dispersing protrusions are formed of a ribbon-like film member including a large number of cuts longitudinally along one side and helically wrapped around the outer peripheral surface of the rotary shaft along the first support member, the ribbon-like film member having a side free from the cuts and serving as a fixation portion.

11. A toner dispersing mechanism according to claim 8 , wherein the first support member is formed integrally with the rotary shaft.

12. A toner dispersing mechanism according to claim 8 , wherein the toner dispersing member further comprises a flexible second support member which is formed on a downstream side with respect to the first support member in a projecting direction of each of the large number of dispersing protrusions, and which has a distal end projecting radially outward with respect to a largest diameter portion of the first support member.

13. A toner dispersing mechanism according to claim 8 , wherein the first support member is formed of a film member having an L-shape in cross section, which comprises:

a fixation portion to be fixed to the rotary shaft; and

a support portion provided substantially perpendicularly upright on one side in a longitudinal direction of the fixation portion and including cuts orthogonal to the longitudinal direction,

the film member being wrapped around the outer peripheral surface of the rotary shaft.

14. A toner dispersing mechanism according to claim 1 ,

wherein the rotary shaft includes a screw portion which exerts a conveying force directed from the toner filling port to the toner discharge port and which is formed adjacently to the large number of dispersing protrusions, and

wherein the toner filling port is formed immediately above the screw portion.

15. A toner dispersing mechanism according to claim 1 , wherein the toner dispersing member is capable of reciprocating in a thrust direction.

16. A developing device, comprising:

the toner dispersing mechanism according to claim 1 ; and

a developing container having an upper portion to which the toner dispersing mechanism is coupled.

17. An image forming apparatus, comprising:

the developing device, according to claim 16 ; and

the toner storage container, the toner storage container being detachably arranged above the toner dispersing mechanism, for storing toner to he replenished into the developing device through intermediation of the toner dispersing mechanism.

18. An image forming apparatus according to claim 17 , further comprising control means for changing a rotational speed of the toner dispersing member based on at least one of an amount of toner to be replenished from the toner storage container and toner fluidity.

19. A toner dispersing mechanism, comprising;

a housing arranged between a toner storage container and a developing device, the housing having a toner filling port communicating to with the toner storage container, and a toner discharge port communicating with the developing device;

a toner dispersing member including

a rotary shaft rotatably supported in the housing, and

a large number of dispersing protrusions, made of an elastic material and formed on an outer peripheral surface of the rotary shaft, for dispersing a lump of toner to come into contact with the large number of dispersing protrusions by rotating the toner dispersing member about the rotary shaft; and

a projecting portion formed continuously at least at a part of an inner wall surface in a longitudinal direction of the housing, the large number of dispersing protrusions facing the inner wall surface part and coming into contact with the projecting portion,

wherein toner replenished from the toner storage container is dispersed and discharged into the developing device, and

wherein the toner dispersing member is forward-and-reverse rotatable.

20. A developing device for use in an image forming apparatus having toner storage container, the developing device comprising:

a toner dispersing mechanism;

a developing container having an upper portion to which toner dispersing mechanism is coupled; and

a stirring-and-conveying member located in the developing container,

the toner dispersing mechanism including

a housing arranged between the toner storage container and the developing container, the housing having a toner filling port communicating with the toner storage container, and a toner discharge port communicating with the developing container, and

a toner dispersing member including a rotary shaft rotatbly supported in the housing, a large number of dispersing protrusions, made of an elastic material and formed on an outer peripheral surface of the rotary shaft, for dispersing a lump of toner to come into contact with the large number of dispersing protrusions by rotating the toner dispersing member about the rotary shaft, and a projecting portion formed continuously at least at a part of an inner wall surface in a longitudinal direction of the housing, the large number of dispersing protrusions facing the inner wall surface part and coming into contact with the projecting portion, wherein toner replenished from the toner storage container is dispersed and discharged into the developing container, and

the stirring-and-conveying member comprising a stirring-and-conveying blade formed on an outer peripheral surface of a stirring-and-conveying rotary shaft, which is provided at a toner dropping position to which toner discharged from the toner discharge port drops, for circulatorily conveying developer in the developing container, the developer existing also at the toner dropping position.

21. A developing device according to claim 20 , wherein the developer existing at the toner dropping position is smaller in height in comparison with an upper surface of the stirring-and-conveying rotary shaft.