US4921768A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrophotographic image forming
Assignee: Seiko Epson Corp
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Filing: 1988-10-05
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Granted: 1990-05-01
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Expires: 2008-10-05
Abstract
Abstract A photoconductive image forming method in a which charged toner contacts a transparent insulating substrate and is exposed from within the substrate. Exposure reduces the resistivity of the toner so that its charge can be reversed by a bias voltage and the exposed toner will adhere to the image forming substrate simultaneously with exposure and then transfer to a transfer medium. In an alternative embodiment of the invention, a layer of toner is applied to an electroconductive substrate and the toner layer is exposed with a latent image. The charge of the exposed toner is reversed and the exposed toner is removed by an intermediate toner removal device. The remaining toner is then transferred to a transfer medium. Toner suitable for use includes azo-type metal containing black dyes which do not absorb the exposure and can be sensitized to the near infrared region. Multicolor toners, each sensitized to a different exposure wavelength are provided so that a single multiple wavelength exposure and a single development can be used to form multicolor images.
Inventors
- 👤 Masanao Kunugi
- 👤 Hajime Kurihara
- 👤 Teruyuki Mizumoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:34
CPC Classifications
G; G03; G03G; G03G13/00; G03G13/01; G03G13/016; G03G15/00; G03G15/22; G03G15/34; G03G15/344; G03G9/00; G03G9/08; G03G9/09; G03G9/0906; G03G9/091; G03G9/0916; G03G9/0926; G03G2215/00; G03G2215/04; G03G2215/0497; G03G2217/00; G03G2217/0091; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/101
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
196 words
A photoconductive image forming method, comprising: charging a quantity of photoconductive toner in which resistivity is reduced on exposure and forming a thin layer of the charged toner with electroconductive charge carriers on an electroconductive transport support; contacting the charged photoconductive toner on the electroconductive transport support to a transparent insulating image forming substrate and applying a DC bias voltage between the transparent insulating image forming substrate and the electroconductive support, the voltage insufficient to reverse the charge of unexposed toner but high enough to reverse the charge of exposed toner; exposing the photoconductive toner on the electroconductive transport support and in contact with the transparent insulating image forming substrate through the substrate to reduce the resistance of the exposed toner so that the bias voltage will selectively reverse the charge of exposed toner on the electroconductive transport support and cause charges to flow from the charge carriers to the toner to selectively transfer and adhere the exposed toner from the electroconductive transport support to the image forming substrate in the form of the image; and transferring the exposed toner adhering to the image forming substrate in the form of the image to a transfer medium.
Claim 2
Dependent Claim
196 words
A photoconductive image forming method, comprising: charging a quantity of photoconductive toner in which resistivity is reduced on exposure and forming a thin layer of the charged toner with electroconductive charge carriers on an electroconductive transport support; contacting the charged photoconductive toner on the electroconductive transport support to a transparent insulating image forming substrate and applying a DC bias voltage between the transparent insulating image forming substrate and the electroconductive support, the voltage insufficient to reverse the charge of unexposed toner but high enough to reverse the charge of exposed toner; exposing the photoconductive toner on the electroconductive transport support and in contact with the transparent insulating image forming substrate through the substrate to reduce the resistance of the exposed toner so that the bias voltage will selectively reverse the charge of exposed toner on the electroconductive transport support and cause charges to flow from the charge carriers to the toner to selectively transfer and adhere the exposed toner from the electroconductive transport support to the image forming substrate in the form of the image; and transferring the exposed toner adhering to the image forming substrate in the form of the image to a transfer medium.
Claim 3
Dependent Claim
64 words
The photoconductive image forming method of claim 1, wherein the toner is a mixture of differently colored toners, each color toner sensitized to a different exposure wavelength and the exposure is a combination of these different wavelengths corresponding to the sensitivity of the toners so that a single multiple wavelength exposure will adhere as many as each differently colored toner to form multicolor images.
Claim 4
Dependent Claim
39 words
The photoconductive image forming method of claim 1, wherein the photoconductive toner is triboelectrically charged by mixing with magnetic conductive carriers to form a two component magnetic brush of toner disposed on the carriers on the electroconductive transport support.
Claim 5
Dependent Claim
18 words
The photoconductive image forming method of claim 1, wherein the photoconductive toners include an azo-type metal black dye.
Claim 6
Dependent Claim
16 words
The photoconductive image forming method of claim 1, wherein the photoconductive toners include a cyanine-type dye.
Claim 7
Dependent Claim
21 words
The method of claim 1, wherein the photoconductive toner includes a colorant and a photoconductive agent dispersed in a binder resin.
Claim 8
Dependent Claim
47 words
The method of claim 6, wherein the toner includes a mixture of differently colored toners, each color toner sensitized to a different exposure wavelength so that a single multiple wavelength exposure will reduce the resistivity of as many as each differently colored toner to form multicolor images.
Claim 9
Dependent Claim
28 words
The method of claim 6, wherein the photoconductive agent is dispersed within a layer of binder resin and coats a particle, the particle including binder resin and colorant.
Claim 10
Dependent Claim
17 words
The toner of claim 6, wherein the toner contains between about 20 to 50% by weight dyestuff.
Claim 11
Dependent Claim
15 words
The toner of claim 6, wherein the photoconductive agent includes zinc oxide and cyanine dye.
Claim 12
Dependent Claim
22 words
The toner of claim 10, wherein the toner contains between about 0.1 to 5 mg cyanine dye per gram of zinc oxide.
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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) | 1993-04-30 | 1993-10-30 | 1994-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-30 | 1997-10-30 | 1998-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-30 | 2001-10-30 | 2002-05-01 | $7700.00 | Window Closed / Lapsed |