Developing device and image forming apparatus including passing developer amount changing mechanism
First Claim
1. A developing device that circulates developer including carrier and toner in a circulation passage having first and second conveyance passages by conveying the developer in a first conveyance direction in the first conveyance passage and conveying the developer in a second conveyance direction in the second conveyance passage, so that the developer is supplied to a developing roller provided along one of the first and second conveyance passages, the developing device comprising:
- a first conveyance member provided in the first conveyance passage and driven to rotate to convey the developer in the first conveyance direction;
a communicating passage through which the developer flows from the first conveyance passage to the second conveyance passage;
a second conveyance member provided in the second conveyance passage and driven to rotate to convey the developer that has flowed through the communicating passage in the second conveyance direction;
a discharge passage extending from an end portion of the first conveyance passage located downstream in the first conveyance direction;
a passing developer amount changing mechanism configured to change an amount of developer per unit time passing through the communicating passage, according to a pressure applied to the developer at a junction between the first conveyance passage and the discharge passage, wherein the passing developer amount changing mechanism comprises a detection unit configured to acquire information indicating fluctuations of the pressure applied to the developer at the junction; and
a movement control unit to control a moving unit based on the acquired information to change a size of an opening of the communicating passage.
2 Assignments
0 Petitions
Accused Products
Abstract
A developing device that circulates developer in a circulation passage having first and second conveyance passages, so that the developer is supplied to a developing roller along the first or second conveyance passages, comprising: a first conveyance member in the first conveyance passage driven to rotate to convey the developer in a first conveyance direction; a communicating passage through which the developer flows from the first to second conveyance passages; a second conveyance member in the second conveyance passage driven to rotate to convey the developer in a second conveyance direction; a discharge passage extending from an end portion of the first conveyance passage located downstream in the first conveyance direction; and a passing developer amount changing mechanism configured to change an amount of developer passing through the communicating passage, according to a pressure applied to the developer at a junction between the first conveyance passage and the discharge passage.
10 Citations
19 Claims
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1. A developing device that circulates developer including carrier and toner in a circulation passage having first and second conveyance passages by conveying the developer in a first conveyance direction in the first conveyance passage and conveying the developer in a second conveyance direction in the second conveyance passage, so that the developer is supplied to a developing roller provided along one of the first and second conveyance passages, the developing device comprising:
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a first conveyance member provided in the first conveyance passage and driven to rotate to convey the developer in the first conveyance direction; a communicating passage through which the developer flows from the first conveyance passage to the second conveyance passage; a second conveyance member provided in the second conveyance passage and driven to rotate to convey the developer that has flowed through the communicating passage in the second conveyance direction; a discharge passage extending from an end portion of the first conveyance passage located downstream in the first conveyance direction; a passing developer amount changing mechanism configured to change an amount of developer per unit time passing through the communicating passage, according to a pressure applied to the developer at a junction between the first conveyance passage and the discharge passage, wherein the passing developer amount changing mechanism comprises a detection unit configured to acquire information indicating fluctuations of the pressure applied to the developer at the junction; and a movement control unit to control a moving unit based on the acquired information to change a size of an opening of the communicating passage. - View Dependent Claims (2, 3, 4, 5, 10, 11, 12)
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6. A developing device that circulates developer including carrier and toner in a circulation passage having first and second conveyance passages by conveying the developer in a first conveyance direction in the first conveyance passage and conveying the developer in a second conveyance direction in the second conveyance passage, so that the developer is supplied to a developing roller provided along one of the first and second conveyance passages, the developing device comprising:
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a first conveyance member provided in the first conveyance passage and driven to rotate to convey the developer in the first conveyance direction; a communicating passage through which the developer flows from the first conveyance passage to the second conveyance passage; a second conveyance member provided in the second conveyance passage and driven to rotate to convey the developer that has flowed through the communicating passage in the second conveyance direction; a discharge passage extending from an end portion of the first conveyance passage located downstream in the first conveyance direction; and a passing developer amount changing mechanism configured to change an amount of developer per unit time passing through the communicating passage, according to a pressure applied to the developer at a junction between the first conveyance passage and the discharge passage, wherein the passing developer amount changing mechanism is a valve made of a flexible material comprising a base fixed to a wall of the communicating passage so as to partially block an opening of the communicating passage and bend as pressure applied to the developer at the junction increases. - View Dependent Claims (7, 9)
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8. A developing device that circulates developer including carrier and toner in a circulation passage having first and second conveyance passages by conveying the developer in a first conveyance direction in the first conveyance passage and conveying the developer in a second conveyance direction in the second conveyance passage, so that the developer is supplied to a developing roller provided along one of the first and second conveyance passages, the developing device comprising:
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a first conveyance member provided in the first conveyance passage and driven to rotate to convey the developer in the first conveyance direction; a communicating passage through which the developer flows from the first conveyance passage to the second conveyance passage; a second conveyance member provided in the second conveyance passage and driven to rotate to convey the developer that has flowed through the communicating passage in the second conveyance direction; a discharge passage extending from an end portion of the first conveyance passage located downstream in the first conveyance direction; and a passing developer amount changing mechanism configured to change an amount of developer per unit time passing through the communicating passage, according to a pressure applied to the developer at a junction between the first conveyance passage and the discharge passage, wherein the passing developer amount changing mechanism is a valve made of a flexible material provided at the communicating passage so as to partially block an opening of the communicating passage and bend as pressure applied to the developer at the junction increases, and the valve has a flexible portion that becomes more flexible closer to a tip thereof.
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13. An image forming apparatus for forming an image by developing an electrostatic latent image on a photoreceptor using a developing device that circulates developer including carrier and toner in a circulation passage having first and second conveyance passages by conveying the developer in a first conveyance direction in the first conveyance passage and conveying the developer in a second conveyance direction in the second conveyance passage, so that the developer is supplied to a developing roller provided along one of the first and second conveyance passages, wherein
the developing device includes: -
a first conveyance member provided in the first conveyance passage and driven to rotate to convey the developer in the first conveyance direction; a communicating passage through which the developer flows from the first conveyance passage to the second conveyance passage; a second conveyance member provided in the second conveyance passage and driven to rotate to convey the developer that has flowed through the communicating passage in the second conveyance direction; a discharge passage extending from an end portion of the first conveyance passage located downstream in the first conveyance direction; a passing developer amount changing mechanism configured to change an amount of developer per unit time passing through the communicating passage, according to a pressure applied to the developer at a junction between the first conveyance passage and the discharge passage, wherein the passing developer amount changing mechanism comprises a detection unit configured to acquire information indicating fluctuations of the pressure applied to the developer at the junction; and a movement control unit to control a moving unit based on the acquired information to change a size of an opening of the communicating passage. - View Dependent Claims (14, 15, 16, 18, 19)
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17. An image forming apparatus for forming an image by developing an electrostatic latent image on a photoreceptor using a developing device that circulates developer including carrier and toner in a circulation passage having first and second conveyance passages by conveying the developer in a first conveyance direction in the first conveyance passage and conveying the developer in a second conveyance direction in the second conveyance passage, so that the developer is supplied to a developing roller provided along one of the first and second conveyance passages, wherein
the developing device includes: -
a first conveyance member provided in the first conveyance passage and driven to rotate to convey the developer in the first conveyance direction; a communicating passage through which the developer flows from the first conveyance passage to the second conveyance passage; a second conveyance member provided in the second conveyance passage and driven to rotate to convey the developer that has flowed through the communicating passage in the second conveyance direction; a discharge passage extending from an end portion of the first conveyance passage located downstream in the first conveyance direction; and a passing developer amount changing mechanism configured to change an amount of developer per unit time passing through the communicating passage, according to a pressure applied to the developer at a junction between the first conveyance passage and the discharge passage, wherein the passing developer amount changing mechanism is a valve made of a flexible material comprising a base fixed to a wall of the communicating passage so as to partially block an opening of the communicating passage and bend as pressure applied to the developer at the junction increases.
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Specification