EP0513820A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Conditioning roller and method of operation for use with a photoconductive drum in an electrophotographic color printer
Assignee: HP Inc
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Filing: 1992-05-15
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Granted: —
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Expires: 2012-05-15
Abstract
Abstract Liquid toner conditioning apparatus and method for use in an electrophotographic color printer and including a stabilizing roller (76) (Figure 3) positioned adjacent to the surface of a photoconductive drum (10) and operative for transforming discrete color toner particles on the surface of the drum (10) into a stabilized unitary polymeric film structure which may be directly transferred onto an adjacent print medium. Advantageously, the stabilizing roller (76) comprises a deformable roller member including a soft open cell conductive foam (78), such as a wettable polyurethane foam which is disposed on a biased slip ring (80). The bias slip ring (80) is in turn formed on the outer surface of a central motor driven metal roller core member (82), and a suitable DC bias connection (86, 88) is applied to the slip ring. The applied DC bias voltage (88) has the same polarity as the desired charge on the toner and of an opposite polarity to the counter ions within the isopar carrier fluid for transporting the toner on the surface of the photoconductive drum (10). Therefore, when the conductive deformable conditioning roller (76) is rotatably driven (48, 50) against the surface of the photoconductive drum (10), it provides three (3) critically important functions. First, it absorbs isopar fluid from the surface of the photoconductive drum (10) which reduces isopar carry out on the media (30). Secondly, it compresses the toner image electrostatically on the drum (10) to preserve its fidelity inasmuch as the polarity of the applied DC bias (88) repels the like charged toner ions into the surface of the photoconductive drum. Thirdly, the DC bias (88) applied to the slip ring (80) pulls counter ions in the isopar fluid from the surface of the drum (10) to thereby leave a desirable positive net charge on the toner as its proceeds to the print media (30).
Inventors
- 👤 Thomas Camis
- 👤 James G. Bearss
- 👤 James A. Hall
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 23:42
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/14; G03G15/16; G03G15/169; G03G15/01; G03G15/0105; G03G15/0131; G03G15/0142; G03G15/0147; G03G15/0152; G03G15/0157; G03G15/0163
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
116 words
A method of electrophotographic color printing where color images are developed using liquid toner on the surface of a photoconductive drum (10) and then transferred to an adjacent print media (30) which passes between a surface of said drum (10) and the surface of an adjacent transfer roller (28), which method comprises the steps of: a. absorbing isopar fluid from the surface of said photoconductive drum (10), while simultaneously, b. electrostatically compressing a toner image on the surface of said drum (10) to preserve the fidelity of said image, while simultaneously c. removing counter ions from said isopar fluid to leave a net charge on said liquid toner as it proceeds to said print media (30).
Claim 2
Dependent Claim
52 words
The method defined in Claim 1 wherein said steps of absorbing, compressing and removing are accomplished simultaneously by rolling a deformable soft wettable conductive foam (78), such as a polyurethane foam, against a surface of said photoconductive drum (10) upon which said liquid toner is used in the development of color images.
Claim 3
Dependent Claim
35 words
A liquid toner conditioner for an electrophotographic color printer of the type having a photoconductive drum (10) therein, said conditioner comprising a deformable roller (76) formed of a soft open cell wettable conductive foam (78).
Claim 4
Dependent Claim
27 words
The conditioner defined in Claim 3 wherein said conductive foam is disposed on a slip ring (80) which is operative to receive a DC bias voltage (88).
Claim 5
Dependent Claim
95 words
The conditioner defined in Claim 4 wherein said slip ring is disposed on a roller core member (82) which is rotatably driven to thereby rotate said conductive foam (78) against the surface of said photoconductive drum (10), whereby said liquid toner conditioner absorbs isopar fluid from the surface of said drum, compresses toner images on the surface of said drum to preserve their fidelity, and attracts counter ions from said isopar fluid from the surface of said drum to leave a desirable net charge on the toner as it proceeds toward a print medium (30).
Claim 6
Dependent Claim
110 words
Electrophotographic color printing apparatus comprising: a photoconductive drum (10), a source of liquid toner (20, 22, 24, 26) adjacent to said photoconductive drum (10), electrostatic transfer means associated with said source of liquid toner for transferring said liquid toner to the surface of said photoconductive drum (10), means (12, 14) adjacent to said photoconductive drum (10) for developing images in said toners thereon, and characterized by liquid toner conditioning means (46, 76) positioned in intimate contact with said photoconductive drum (10) for preparing and conditioning the developed color liquid toner layers on said drum (10) for direct transfer from the surface of said drum to an adjacent print medium (30).
Claim 7
Dependent Claim
90 words
The apparatus as claimed in Claim 6 wherein said liquid toner conditioning means includes a roller member rotatably mounted adjacent to said photoconductive drum (10) and having an inner core member (56, 82) and an outer cover (70, 72, 78) thereon operative to rotate in direct contact with the surface of said photoconductive drum (10), thereby stabilizing the image on the surface of said drum (10) and preserving its fidelity and preventing it from adhering to said roller member while the amount of fluid vehicle carrying said toners is reduced.
Claim 8
Independent Claim
142 words
The apparatus as claimed in claims 6 or 7 further characterized in that said liquid toner conditioning means includes a deformable roller (76) comprising a wettable soft open cell conductive foam (78), such as a polyurethane foam, disposed on a slip ring (80), with said slip ring (80) being, in turn, formed on an inner motor driven metal roller core member (82), whereby a suitable DC bias (88) may be applied to said slip ring (80) with a polarity opposite to that of the charge on counter ions within a carrier fluid for said color toner on said photoconductive drum, whereby when said conditioning roller (76) is rotatably driven against the surface of said photoconductive drum (10) it absorbs isopar fluid from said surface and also compresses the toner image electrostatically on the surface of said photoconductive drum to preserve its fidelity.
Claim 9
Dependent Claim
56 words
The apparatus defined in claim 7 which further includes: a. means for affixing a source of heat (52) adjacent to said inner core member (56) of said conditioning means, and b. means (62) connecting said inner core member (56) of said condition means to a source (66) of either AC bias or DC bias or both.
Claim 10
Independent Claim
26 words
The apparatus claimed in any one of Claims 6, 7 or 9 wherein said outer cover (70) of said conditioning means is a soft elastomeric material.
Claim 11
Dependent Claim
41 words
The apparatus as claimed in Claim 6 wherein said liquid toner conditioning means (46) includes means for stabilizing and compressing the toner image on the surface of said photoconductive drum (10) using both thermal (52), electrostatic (66) and mechanical (72) forces.
Claim 12
Independent Claim
84 words
A method for directly transferring developed color images on the surface of a photoconductive drum (10) to an adjacent print media (30) characterized by converting developed color toner layers on the surface of a photoconductive drum (10) from discrete particle form to a thin stabilized polymeric film structure containing said developed images and further reducing the liquid content of said toner layers from the level used to initially apply the liquid toners (20, 22, 24, 26) to the surface of said photoconductive drum (10).
Claim 13
Dependent Claim
73 words
The method claimed in Claim 12 wherein said conversion is accomplished by using either electrostatic forces (66) or mechanical forces (72) or both and further and alternatively using thermal energy applied to said photoconductive drum (10) if desired, whereby a controlled low level heating (52) applied to the surface of said drum (10) serves to initiate the transformation of said toner layers from discrete toner particles into a unitary stabilized polymeric film structure.
Claim 14
Dependent Claim
121 words
Conditioning and stabilizing apparatus for integrating and converting toner from discrete particle form into a cohesive and unitary polymeric film, comprising: a. photoconductive means (10) having an outer surface thereof for receiving successive films of cyan, yellow, magenta, and black liquid toners (20, 22, 24, 26), and b. conditioning and stabilizing means (46, 76) positioned in intimate contact with said surface of said photoconductive member (10) and operative for applying a combination of mechanical pressure (72, 84) and electrostatic forces (66, 88) to said surface of said photoconductive member, whereby said liquid toners (20, 22, 24, 26) may be compressed into a unitary and cohesive polymeric film with the toner particles therein recharged for subsequent transfer to a selected print medium.
Claim 15
Dependent Claim
82 words
The apparatus claimed in Claim 14 wherein said conditioning and stabilizing means includes: a. a roller apparatus having an inner core member (56) containing a heating element (52) and connected to a source of either AC bias or DC bias (66) or both, and b. an outer roller member (70) surrounding said inner core member and operative to be driven against the surface of said photoconductive member (10) for applying a combination of thermal (52), mechanical (72), and electrical forces (66) thereto.
Claim 16
Dependent Claim
89 words
The apparatus claimed in Claim 14 wherein said conditioning and stabilizing means includes a deformable roller (76) comprising a wettable soft open cell conductive foam (78), such as a polyurethane foam, disposed on a slip ring (80), with said slip ring (80) being, in turn, formed on an inner motor driven metal roller core member (82), whereby a suitable DC bias (88) may be applied to said slip ring (80) with a polarity opposite to that of the charge on counter ions within a carrier fluid for said toner.
Claim 17
Independent Claim
80 words
A method for converting toners in discrete particle form into a cohesive and unitary polymeric film which comprises the steps of: a. developing a plurality of color and black liquid transparent toners (20, 22, 24, 26) on the surface of a photoconductive member (10), and b. simultaneously applying mechanical (72, 84), and electrical (66, 88) energy in series to said multiple liquid color toners in discrete particle form to thereby convert said toners into said cohesive and unitary polymeric film.
Claim 18
Dependent Claim
45 words
The method defined in Claim 10 which further includes, in step b., simultaneously removing toner carrier fluid such as an isopar from the unitary polymeric film being developed to thereby reduce the amount of carrier fluid that is ultimately transferred to a print medium (30).
Claim 19
Independent Claim
39 words
The method defined in Claims 17 or 18 which includes rotatably driving a toner conditioning roller (46) against the surface of said photoconductive member (10) to thereby convert said discrete toner particles to said cohesive and unitary polymeric film.
Claim 20
Dependent Claim
266 words
Electrophotographic color printing apparatus of the type including a photoconductive drum (10) for receiving a source of liquid toner adjacent to one surface thereof, means (20, 22, 24, 26) associated with the liquid toner for transferring the liquid toner to the surface of the photoconductive drum, development means (12, 14) adjacent to the photoconductive drum (10) for developing images in toners thereon, and transfer means (28) for transferring images from the surface of the photoconductive drum (10) to an adjacent print media (30), characterized in that: an improved conditioning roller apparatus (76) is rotatably mounted and rotatably driven in intimate contact with the surface of the photoconductive drum (10) and includes a deformable soft open cell conductive foam roller (78) disposed upon the surface of a biased slip ring (80), and a motor driven metal roller core member (82) positioned within the interior of the biased slip ring (80), and means (86) for applying a DC bias voltage (88) to said slip ring (80) with a polarity opposite to the polarity of the charge on the counter ions within an isopar carrier fluid for color toner on the photoconductive drum, so that when the conductive deformable conditioning roller (76) is rotatably driven against the surface of the photoconductive drum (10), it not only absorbs isopar fluid from the surface of the photoconductive drum (10), but it also compresses the toner image electrostatically on the surface of the drum to preserve its fidelity and thereby further operates to leave a net charge on the toner as is desirable as the toner proceeds toward the print media (30).
References Cited (Backward Citations)
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