Developing device and image forming apparatus
First Claim
1. A developing device having comprising:
- a housing that houses a two-component developer containing a carrier and a toner, wherein the developer is replenished in the housing while the developer is gradually ejected to outside from an outlet of the housing;
a transport passage provided in the housing and in which the developer is transported;
a transport member provided in the housing and configured to rotate to transport the developer;
an ejection passage which diverges from the transport passage such that a part of the developer transported in the transport passage is conveyed in the ejection passage to the outlet; and
a restriction unit configured to restrict an amount of developer ejected from the outlet so that a first amount of developer is ejected per rotation of the transport member from the outlet when the transport member rotates at a first speed, and a second amount of developer is ejected per rotation of the transport member from the outlet when the transport member rotates at a second speed that is higher than the first speed, wherein the second amount of developer ejected per rotation of the transport member when the transport member rotates at the second speed is smaller than the first amount of developer ejected per rotation of the transport member when the transport member rotates at the first speed, andwherein the restriction unit comprises;
a shutter configured to move and close the outlet by covering the outlet; and
a moving mechanism configured to move the shutter so that the outlet is opened for a first time period per rotation of the transport member when the transport member rotates at the first speed, and the outlet is opened for a second time period per rotation of the transport member when the transport member rotates at the second speed, the second time period being shorter than the first time period,wherein the moving mechanism moves the shutter so as to close the outlet so that developer is not ejected from the outlet during periods other than the first time period or the second time period.
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Accused Products
Abstract
A developing device having a housing that houses two-component developer containing carrier and toner, replenishing replenishment carrier to the housing while gradually ejecting developer to outside from an outlet. The developing device includes: transport passage provided in the housing so that developer is transported therein; transport member provided in the housing and rotates to transport the developer; ejection passage having diverged from the transport passage so that a part of the developer transported in the transport passage is conveyed therein to the outlet; and restriction unit configured to restrict an amount of ejected developer so that a first amount of developer is ejected from the outlet when the transport member rotates at a first speed, and a second amount of developer is ejected when it rotates at a second speed. The second amount is smaller than the first amount. The second speed is higher than the first speed.
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Citations
10 Claims
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1. A developing device having comprising:
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a housing that houses a two-component developer containing a carrier and a toner, wherein the developer is replenished in the housing while the developer is gradually ejected to outside from an outlet of the housing; a transport passage provided in the housing and in which the developer is transported; a transport member provided in the housing and configured to rotate to transport the developer; an ejection passage which diverges from the transport passage such that a part of the developer transported in the transport passage is conveyed in the ejection passage to the outlet; and a restriction unit configured to restrict an amount of developer ejected from the outlet so that a first amount of developer is ejected per rotation of the transport member from the outlet when the transport member rotates at a first speed, and a second amount of developer is ejected per rotation of the transport member from the outlet when the transport member rotates at a second speed that is higher than the first speed, wherein the second amount of developer ejected per rotation of the transport member when the transport member rotates at the second speed is smaller than the first amount of developer ejected per rotation of the transport member when the transport member rotates at the first speed, and wherein the restriction unit comprises; a shutter configured to move and close the outlet by covering the outlet; and a moving mechanism configured to move the shutter so that the outlet is opened for a first time period per rotation of the transport member when the transport member rotates at the first speed, and the outlet is opened for a second time period per rotation of the transport member when the transport member rotates at the second speed, the second time period being shorter than the first time period, wherein the moving mechanism moves the shutter so as to close the outlet so that developer is not ejected from the outlet during periods other than the first time period or the second time period. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A developing device comprising:
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a housing that houses a two-component developer containing a carrier and a toner, wherein the developer is replenished in the housing while the developer is gradually ejected to outside from an outlet of the housing; a transport passage provided in the housing and in which the developer is transported; a transport member provided in the housing and configured to rotate to transport the developer; an ejection passage which diverges from the transport passage such that a part of the developer transported in the transport passage is conveyed in the ejection passage to the outlet; and a restriction unit configured to restrict an amount of developer ejected from the outlet so that a first amount of developer is ejected per rotation of the transport member from the outlet when the transport member rotates at a first speed, and a second amount of developer is ejected per rotation of the transport member from the outlet when the transport member rotates at a second speed that is higher than the first speed, wherein the second amount of developer ejected per rotation of the transport member when the transport member rotates at the second speed is smaller than the first amount of developer ejected per rotation of the transport member when the transport member rotates at the first speed, wherein; the restriction unit includes; a shutter configured to move and cover the outlet; and a moving mechanism configured to move the shutter so that an opening area of the outlet is a first size when a rotation speed of the transport member is the first speed, and an opening area of the outlet is a second size when the rotation speed of the transport member is the second speed, the second size being smaller than the first size, the ejection passage comprises a first cylindrical member, and the outlet is provided in a circumferential surface of the first cylindrical member, the shutter comprises a second cylindrical member which has a hole provided in a circumferential surface thereof and which has one axial end which is open and another axial end which has a bottom, and the shutter is fixed on the first cylindrical member at a side of the open end thereof so as to be rotatable in a circumferential direction relative to the first cylindrical member. - View Dependent Claims (8, 9)
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10. An image forming apparatus comprising:
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a developing device; a driver configured to drive a transport member included in the developing device; and a controller configured to control the driver to stop the transport member from rotating, to be in a state in which an outlet of an ejection passage in the developing device is closed by a shutter provided in the developing device, wherein the developing device comprises; a housing that houses a two-component developer containing a carrier and a toner, wherein the developer is replenished in the housing while the developer is gradually ejected to outside from the outlet; a transport passage provided in the housing so that the developer is transported therein; the transport member, wherein the transport member is provided in the housing and configured to rotate to transport the developer; the ejection passage, wherein the ejection passage diverges from the transport passage so that a part of the developer transported in the transport passage is conveyed through the ejection passage to the outlet; and a restriction unit configured to restrict an amount of developer ejected from the ejection passage so that a first amount of developer is ejected per rotation of the transport member from the outlet when the transport member rotates at a first speed, and a second amount of developer is ejected per rotation of the transport member from the outlet when the transport member rotates at a second speed that is higher than the first speed, wherein the second amount of developer ejected per rotation of the transport member when the transport member rotates at the second speed is smaller than the first amount of developer ejected per rotation of the transport member when the transport member rotates at the first speed, wherein the restriction unit includes; a shutter configured to move and close the outlet by covering the outlet; and a moving mechanism configured to move the shutter so that the outlet is opened for a first time period per rotation of the transport member when the transport member rotates at the first speed, and the outlet is opened for a second time period per rotation of the transport member when the transport member rotates at the second speed, the second time period being shorter than the first time period, and wherein; the ejection passage comprises a first cylindrical member, the outlet is provided in a circumferential surface of the first cylindrical member, the shutter comprises a second cylindrical member having a hole provided in a circumferential surface thereof, and the shutter is fixed on the first cylindrical member to be rotatable in a circumferential direction relative to the first cylindrical member, and is disposed at a position where the hole is aligned with the outlet in an axis direction of the first cylindrical member, the shutter is rotatable to a position where the hole overlaps with the outlet in a radial direction of the first cylindrical member, and to a position where the hole does not overlap with the outlet such that the shutter closes the outlet, and the moving mechanism causes the shutter to rotate in a same direction as a rotation of the transport member in coordination with the transport member.
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Specification