US4896625A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Developing device
Assignee: Ricoh Co Ltd
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Filing: 1988-05-31
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Granted: 1990-01-30
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Expires: 2008-05-31
Abstract
Abstract A developing device for developing an electrostatic latent image formed on an image bearing member such as a photosensitive member for use in an electrophotographic copying machine and the like using magnetic toner particles includes a rotatable sleeve, a magnet roll disposed inside of the sleeve and a doctor blade pressed against the sleeve for charging and forming a thin film of toner particles to be used in developing the latent image. In one form, the blade is provided movably in parallel with the rotating axis of the sleeve. In another form, an electrically conductive brush is provided to remove residual charges from the sleeve after each developing operation. In a further form, the tip end of the blade is disposed between the two adjacent magnetic poles of the magnet roll. In a still further form, the blade is constructed to have a two-part structure.
Inventors
- 👤 Koji Sakamoto
- 👤 Toshio Kaneko
- 👤 Wataru Yasuda
- 👤 Fuchio Kanno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:38
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/09
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
198 words
A developing device for developing an electrostatic latent image formed on an image bearing member using toner particles, comprising: toner carrier means for carrying said toner particles along a predetermined path, a part of which defines a developing section where said electrostatic latent image is developed by said toner particles; supplying means for supplying said toner particles to said toner carrier means; pressure means disposed between said supplying means and said developing section in pressure contact with said toner carrier means for forming a thin film of toner particles which are charged to a predetermined polarity; and discharging means disposed downstream of said developing section but upstream of said supplying means for removing any excess remaining charge from those portions of said toner carrier means where said toner particles have been transferred to said image bearing member as a result of development at said developing section while keeping those toner particles which have not been used at said developing section carried on said toner carrier means, said discharging means being disposed at a position where said toner particles to be supplied to said toner carrier means is absent and in contact with said toner carrier means after development.
Claim 2
Dependent Claim
198 words
A developing device for developing an electrostatic latent image formed on an image bearing member using toner particles, comprising: toner carrier means for carrying said toner particles along a predetermined path, a part of which defines a developing section where said electrostatic latent image is developed by said toner particles; supplying means for supplying said toner particles to said toner carrier means; pressure means disposed between said supplying means and said developing section in pressure contact with said toner carrier means for forming a thin film of toner particles which are charged to a predetermined polarity; and discharging means disposed downstream of said developing section but upstream of said supplying means for removing any excess remaining charge from those portions of said toner carrier means where said toner particles have been transferred to said image bearing member as a result of development at said developing section while keeping those toner particles which have not been used at said developing section carried on said toner carrier means, said discharging means being disposed at a position where said toner particles to be supplied to said toner carrier means is absent and in contact with said toner carrier means after development.
Claim 3
Dependent Claim
40 words
The device of claim 1 wherein said toner carrier means includes an electrically conductive layer, a dielectric layer formed on said conductive layer and a plurality of floating electrodes provided in said dielectric layer and spaced apart from one another.
Claim 4
Dependent Claim
24 words
The device of claim 2 further comprising attracting means for attracting said toner particles to said toner carrier means with a predetermined attracting force.
Claim 5
Dependent Claim
53 words
The device of claim 3 wherein said toner particles are magnetically attractable substantially and said attracting means includes means for generating a magnetic field to be applied to said toner carrier means for causing said magnetic toner particles to be attracted to said toner carrier means while being transported along said predetermined path.
Claim 6
Dependent Claim
35 words
The device of claim 4 wherein said pressure means is directed in a direction counter to a movement of said magnetic toner particles at a contact between said pressure means and said toner carrier means.
Claim 7
Dependent Claim
41 words
The device of claim 5 wherein said toner carrier means is formed in a shape of a sleeve which is driven to rotate in a predetermined direction so that said predetermined path is defined by a peripheral surface of said sleeve.
Claim 8
Dependent Claim
32 words
The device of claim 6 wherein said discharging means includes an electrically conductive brush disposed in contact with or spaced apart over a small distance from the peripheral surface of said sleeve.
Claim 9
Dependent Claim
40 words
The device of claim 7 further comprising means for applying a predetermined potential connected to said conductive layer, said brush and said pressure means thereby maintaining said conductive layer, said brush and said pressure means substantially at said predetermined potential.
Claim 10
Dependent Claim
45 words
The device of claim 4 further comprising moving means for moving said pressure means in a direction perpendicular to a relative moving direction between said toner carrier means and said pressure means while maintaining said pressure means in pressure contact with said toner carrier means.
Claim 11
Dependent Claim
68 words
The device of claim 4 wherein said pressure means has a Young's modulus E in N·m -2 thickness d in meters and length l in meters from its supporting point to a contact point between said pressure means and said toner carrier means, and these parameters satisfy the condition of Ed 3 /l 3 being equal to or larger than 2,500 but equal to or smaller than 250,000.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-01-29 | 1993-07-31 | 1994-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-29 | 1997-07-31 | 1998-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-29 | 2001-07-31 | 2002-01-30 | $7700.00 | Window Closed / Lapsed |