US4382420A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Development apparatus
Assignee: Ricoh Co Ltd
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Filing: 1981-01-28
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Granted: 1983-05-10
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Expires: 2001-01-28
Abstract
Abstract An apparatus for developing a latent electrostatic image formed on a photoconductive recording material in a dry type electrophotographic copying machine typically employing a one-component type developer comprises a conductive electrode held in contact with the developer. The electrode is connected to a power source through a switching device and serves to charge the developer to a predetermined polarity with a predetermined potential before the latent image is developed. In this way, the latent image can be developed selectively as either a normal image or a reverse image quite easily.
Inventors
- 👤 Teruyuki Ohnuma
- 👤 Seiichi Miyakawa
- 👤 Nobuo Mochizuki
- 👤 Hajime Oyama
- 👤 Yukio Tabata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:49
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/0806; G03G15/0812; G03G2215/00; G03G2215/06; G03G2215/0602; G03G2215/0604; G03G2215/0607; G03G2215/0614; G03G2215/0634; G03G2215/0636; G03G2215/0641
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
152 words
A development apparatus for developing a latent electrostatic image formed on a photoconductor, comprising: container means for holding a one-component type developer and having an outlet for discharging said developer therefrom, said developer having a volume resistivity of no less than about 10 9 ohm-cm; developer supplying means, having an endless conductive surface of a material having a volume resistivity no greater than about 10 8 ohm-cm, for supplying said developer discharged from said container means to said photoconductor; means including a conductive element located at said outlet and held in contact with said developer for forming a toner layer with a predetermined thickness on said endless conductive surface when said developer is supplied from said container means to said photoconductor by said developer supplying means; and power source means connected to said conductive element for providing a voltage of a predetermined polarity thereto for charging said developer to a predetermined polarity.
Claim 2
Dependent Claim
152 words
A development apparatus for developing a latent electrostatic image formed on a photoconductor, comprising: container means for holding a one-component type developer and having an outlet for discharging said developer therefrom, said developer having a volume resistivity of no less than about 10 9 ohm-cm; developer supplying means, having an endless conductive surface of a material having a volume resistivity no greater than about 10 8 ohm-cm, for supplying said developer discharged from said container means to said photoconductor; means including a conductive element located at said outlet and held in contact with said developer for forming a toner layer with a predetermined thickness on said endless conductive surface when said developer is supplied from said container means to said photoconductor by said developer supplying means; and power source means connected to said conductive element for providing a voltage of a predetermined polarity thereto for charging said developer to a predetermined polarity.
Claim 3
Dependent Claim
29 words
An apparatus as in claim 1 further comprising current control means connected between said conductive element and said power source means for controlling the current to said conductive element.
Claim 4
Dependent Claim
42 words
An apparatus as in claim 1 wherein said developer supplying means comprises a roller and further comprising switch means for opening and closing the connection between said conductive element and said power source means in response to the rotation of said roller.
Claim 5
Dependent Claim
19 words
An apparatus as in claim 1 further comprising means for applying a bias voltage to said endless conductive surface.
Claim 6
Dependent Claim
24 words
An apparatus as in claim 4 further comprising means for selectively increasing the voltage of said power source means and said bias voltage means.
Claim 7
Dependent Claim
50 words
An apparatus as in claim 1, further comprising conductive electrode means formed by a first electrode disposed above said endless conductive surface and a second electrode disposed beneath and in contact with said endless conductive surface, one of said first and second electrode being connected to said power source means.
Claim 8
Dependent Claim
25 words
An apparatus as in claim 1 further comprising switch means for reversing the predetermined polarity of said power source means applied to said conductive element.
Claim 9
Dependent Claim
34 words
An apparatus as in claim 1 wherein the volume resisitivity of said material is not more than 10 5 ohm-cm and the volume resistivity of said developer is greater than about 10 14 ohm-cm.
Claim 10
Independent Claim
117 words
An apparatus for developing a latent electrostatic image formed on a charged photoconductor by exposure of an original, comprising a supply of developer having a volume resistivity of at least about 10 9 ohm-cm; transport means for bringing said developer into contact with said latent image; and charging means including a conductive electrode connected to a source of potential for applying a voltage to said developer for causing it to be attracted to selected portions of said latent image, said charging means including selection means for changing the polarity of the potential connected to said electrode for selectively applying a voltage to said electrode suitable for developing a positive or negative image of the original, as desired.
Claim 11
Independent Claim
117 words
An apparatus for developing a latent electrostatic image formed on a charged photoconductor by exposure of an original, comprising a supply of developer having a volume resistivity of at least about 10 9 ohm-cm; transport means for bringing said developer into contact with said latent image; and charging means including a conductive electrode connected to a source of potential for applying a voltage to said developer for causing it to be attracted to selected portions of said latent image, said charging means including selection means for changing the polarity of the potential connected to said electrode for selectively applying a voltage to said electrode suitable for developing a positive or negative image of the original, as desired.
Claim 12
Dependent Claim
47 words
An apparatus as in claim 9, said transport means including an endless surface having a volume resistivity no greater than 10 8 ohm-cm, said electrode being spaced from a portion of said surface to provide a gap for applying a potential to the developer within said gap.
Claim 13
Dependent Claim
33 words
An apparatus as in claim 10, said electrode being positioned adjacent to where said developer leaves its supply so that the size of said gap controls the thickness of developer on said surface.
Claim 14
Dependent Claim
38 words
An apparatus as in claim 10, including bias means for applying a potential to said endless surface whereby the voltage level of said charged developer depends on the potential applied to both said electrode and said endless surface.
Claim 15
Dependent Claim
24 words
An apparatus as in claim 12, including means for adjusting the voltage level of said bias means cooperatively with that of said charging means.
Claim 16
Dependent Claim
19 words
An apparatus as in claim 9, further including means for limiting the level of current applied to said electrode.
Claim 17
Dependent Claim
37 words
An apparatus as in claim 9, said selection means including a switch connecting either a positive terminal or a negative terminal of a power source to said electrode while connecting the other of said terminals to ground.
Claim 18
Dependent Claim
158 words
A developement apparatus for developing a latent electrostatic image formed on a photoconductor, comprising: container means for holding a one-component type developer and having an outlet for discharging said developer therefrom, said developer having a volume resistivity of no less than about 10 9 ohm-cm; developer supplying means, having an endless conductive surface of a material having a volume resistivity no greater than about 10 8 ohm-cm, for supplying said developer discharged from said container means to said photoconductor; doctor means for forming a toner layer with a predetermined thickness on said endless conductive surface when said developer is supplied from said container means to said photoconductor by said developer supplying means; power source means for providing a voltage of a predetermined polarity; and conductive electrode means connected to said power source means for charging said developer to a predetermined polarity; said conductive electrode means being disposed within said container means so as to contact said developer therewithin.
Claim 19
Dependent Claim
158 words
A developement apparatus for developing a latent electrostatic image formed on a photoconductor, comprising: container means for holding a one-component type developer and having an outlet for discharging said developer therefrom, said developer having a volume resistivity of no less than about 10 9 ohm-cm; developer supplying means, having an endless conductive surface of a material having a volume resistivity no greater than about 10 8 ohm-cm, for supplying said developer discharged from said container means to said photoconductor; doctor means for forming a toner layer with a predetermined thickness on said endless conductive surface when said developer is supplied from said container means to said photoconductor by said developer supplying means; power source means for providing a voltage of a predetermined polarity; and conductive electrode means connected to said power source means for charging said developer to a predetermined polarity; said conductive electrode means being disposed within said container means so as to contact said developer therewithin.
Claim 20
Dependent Claim
68 words
An apparatus as in claim 16, said container means serving to hold a supply of developer in contact with the endless surface of said developer supply means, said doctor means including an element located at the outlet of said container, said element being spaced from said endless surface a distance less than the spacing between said endless surface and said conductive electrode means disposed within said container means.
Claim 21
Dependent Claim
30 words
An apparatus as in claim 16 further comprising current control means connected between said conductive electrode means and said power source means for controlling the current to said electrode means.
Claim 22
Dependent Claim
43 words
An apparatus as in claim 16 wherein said developer supplying means comprises a roller and further comprising switch means for opening and closing the connection between said conductive electrode means and said power source means in response to the rotation of said roller.
Claim 23
Dependent Claim
19 words
An apparatus as in claim 16 further comprising means for applying a bias voltage to said endless conductive surface.
Claim 24
Dependent Claim
24 words
An apparatus as in claim 20, further comprising means for selectively increasing the voltage of said power source means and said bias voltage means.
Claim 25
Dependent Claim
48 words
An apparatus as in claim 16 wherein said conductive electrode means comprises a first electrode disposed above said endless conductive surface and a second electrode disposed beneath and in contact with said endless surface, one of said first and second electrodes being connected to said power supply means.
Claim 26
Dependent Claim
26 words
An apparatus as in claim 16 further comprising switch means for reversing the predetermined polarity of said power source means applied to said conductive electrode means.
Claim 27
Dependent Claim
34 words
An apparatus as in claim 16 wherein the volume resistivity of said material is not more than 10 5 ohm-cm and the volume resistivity of said developer is greater than about 10 14 ohm-cm.
Claim 28
Dependent Claim
38 words
An apparatus as in claim 1 or 16 wherein said developer supplying means comprises a roller comprising a metal core, an elastic layer on said metal core, and a thin, comparatively hard surface layer on said elastic layer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-05-09 | 1986-11-08 | 1987-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-09 | 1990-11-08 | 1991-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-09 | 1994-11-08 | 1995-05-10 | $7700.00 | Window Closed / Lapsed |