Patent US4448872A successfully refreshed from Google Patents.
US4448872A
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Duplex imaging with pressure transfixing
Assignee: Delphax Systems Inc
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Filing: 1982-09-29
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Granted: 1984-05-15
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Expires: 2002-09-29
Abstract
Abstract Method and apparatus for duplex electrostatic imaging wherein a toner image is transferred and simultaneously fixed to two sides of a receptor medium using high pressure. The first toner image is created on a dielectric image roller and pressure transferred to a transfer roller moving at an identical surface velocity. A second toner image is subsequently formed on the image roller, and the two images are simultaneously transferred and fused to opposite sides of a receptor sheet at the nip. The image roller advantageously includes a hard, very smooth dielectric surface, while the transfer roller has a moderately smooth, compliant surface. The transfer roller surface preferably comprises an engineering thermoplastic or thermoset material characterized by a relatively low coefficient of friction in order to provide high transfer efficiency to the receptor sheet. The duplex imaging apparatus may be incorporated into electrostatic printers and copiers with suitable adaptations in the image generating stages.
Inventors
- 👤 Casey S. Vandervalk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:38
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/22; G03G15/23; G03G15/231; G03G15/232; G03G15/24
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
172 words
A method of duplex imaging which comprises forming a first toner image on the surface of an image roller, said image surface having a smoothness in excess of 20 microinch rms and a modulus of elasticity in compression of at least 10 7 PSI; transferring said first toner image to the surface of a transfer roller in rolling contact with said image roller under a compressive load, said transfer roller having a surface layer of a material selected from the group consisting of engineering thermoplastic and engineering thermoset materials; creating a second toner image on the surface of the image roller; passing an image receptor sheet between said image roller and said transfer roller; and transferring said first toner image from said transfer roller to one side of said image transfer sheet and simultaneously transferring said second toner image from said image roller to an opposite side of said image receptor sheet, wherein the rollers are pressed together sufficiently to fuse the toner images to said image receptor sheet at ambient temperatures.
Claim 2
Independent Claim
172 words
A method of duplex imaging which comprises forming a first toner image on the surface of an image roller, said image surface having a smoothness in excess of 20 microinch rms and a modulus of elasticity in compression of at least 10 7 PSI; transferring said first toner image to the surface of a transfer roller in rolling contact with said image roller under a compressive load, said transfer roller having a surface layer of a material selected from the group consisting of engineering thermoplastic and engineering thermoset materials; creating a second toner image on the surface of the image roller; passing an image receptor sheet between said image roller and said transfer roller; and transferring said first toner image from said transfer roller to one side of said image transfer sheet and simultaneously transferring said second toner image from said image roller to an opposite side of said image receptor sheet, wherein the rollers are pressed together sufficiently to fuse the toner images to said image receptor sheet at ambient temperatures.
Claim 3
Dependent Claim
60 words
The method of claim 1 wherein the image roller has a dielectric surface layer, and wherein the steps of forming the first and second toner images each comprise forming a latent electrostatic image on said dielectric surface layer, and applying toner to said dielectric surface layer to form a toner image as a visible counterpart to the latent electrostatic image.
Claim 4
Dependent Claim
40 words
The method of claim 1 wherein the image receptor sheet passes between the image roller and transfer roller with a surface speed differential with respect to the roller surfaces, thereby to enhance transfer and fusing of the toner images thereto.
Claim 5
Dependent Claim
38 words
The method of claim 2 wherein the image roller is comprised of aluminum anodized to form an oxide surface layer, which is impregnated with a dielectric material and polished to a smoothness in excess of 20 microinch rms.
Claim 6
Dependent Claim
79 words
The method of claim 1, for electrographic printing, wherein the steps of creating the first and second latent electrostatic images on the image roller are effected by a matrix print head comprising a multiplicity of row electrodes and column electrodes forming cross points in a matrix array, such that a matrix point latent electrostatic image is created for a given cross point location in response to actuating signals to the row and column electrodes forming the given cross point.
Claim 7
Dependent Claim
32 words
The method of claim 1, further comprising the step of skewing the image and transfer rollers sufficiently to ensure substantially complete toner transfer from the image roller to the image receptor sheet.
Claim 8
Dependent Claim
25 words
The method of claim 1 wherein the transfer roller is comprised of a material selected from the group consisting of copolymers and homopolymers of polyoxymethylene.
Claim 9
Dependent Claim
22 words
The method of claim 1 wherein the surface layer of the transfer roller is comprised of a material of low frictional coefficient.
Claim 10
Dependent Claim
14 words
The method of claim 1 wherein the toner comprises a hydrophobic, single component powder.
Claim 11
Dependent Claim
19 words
The method of claim 1 wherein the dielectric surface of the image roller comprises a hard, abrasion resistant material.
Claim 12
Independent Claim
178 words
A method of duplex imaging which comprises forming a first toner image on the surface of an image roller comprised of aluminum anodized to form an oxide surface layer, which is impregnated with a dielectric material and polished to a smoothness in excess of 20 microinch rms; transferring said first toner image to the surface of a transfer roller in rolling contact with said image roller under a compressive load, said transfer roller having a surface layer of a material selected from the group consisting of copolymers and homopolymers of polyoxymethylene, polyesters, polyvinylchloride, and polycarbonates; forming a second toner image on the surface of said image roller; passing an image receptor sheet between said image roller and said transfer roller; and transferring said first toner image from said transfer roller to one side of said image receptor sheet and simultaneously transferring said second toner image from said image roller to an opposite side of said image receptor sheet, wherein the rollers are pressed together sufficiently to fuse the toner images to said image receptor sheet at ambient temperatures.
Claim 13
Independent Claim
178 words
A method of duplex imaging which comprises forming a first toner image on the surface of an image roller comprised of aluminum anodized to form an oxide surface layer, which is impregnated with a dielectric material and polished to a smoothness in excess of 20 microinch rms; transferring said first toner image to the surface of a transfer roller in rolling contact with said image roller under a compressive load, said transfer roller having a surface layer of a material selected from the group consisting of copolymers and homopolymers of polyoxymethylene, polyesters, polyvinylchloride, and polycarbonates; forming a second toner image on the surface of said image roller; passing an image receptor sheet between said image roller and said transfer roller; and transferring said first toner image from said transfer roller to one side of said image receptor sheet and simultaneously transferring said second toner image from said image roller to an opposite side of said image receptor sheet, wherein the rollers are pressed together sufficiently to fuse the toner images to said image receptor sheet at ambient temperatures.
Claim 14
Dependent Claim
60 words
The method of claim 11 wherein the image roller has a dielectric surface layer, and wherein the steps of forming the first and second toner images each comprise forming a latent electrostatic image on said dielectric surface layer, and applying toner to said dielectric surface layer to form a toner image as a visible counterpart to the latent electrostatic image.
Claim 15
Dependent Claim
31 words
The method of claim 11, further comprising the step of skewing the image and transfer rollers sufficiently to ensure substantially complete toner transfer from the image roller to the image receptor.
Claim 16
Dependent Claim
40 words
The method of claim 11 wherein the image receptor sheet passes between the image roller and transfer roller with a surface speed differential with respect to the roller surfaces, thereby to enhance transfer and fusing of the toner images thereto.
Claim 17
Dependent Claim
14 words
The method of claim 11 wherein the toner comprises a hydrophobic, single component powder.
Claim 18
Independent Claim
177 words
A method of duplex imaging which comprises creating a first toner image on the surface of an image roller, said image surface having a smoothness in excess of 20 microinch rms and a modulus of elasticity in compression of at least 10 7 PSI; transferring said first toner image to the surface of a transfer roller in rolling contact with said image roller under a compressive load, said transfer roller having a surface layer of an engineering thermoplastic or thermoset material; creating a second toner image on the surface of the image roller; passing an image receptor sheet between said image roller and said transfer roller; and transferring said first toner image from said transfer roller to one side of said image transfer sheet and simultaneously transferring said second toner image from said image roller to an opposite side of said image receptor sheet, wherein the image roller and transfer roller are disposed at an axial skew, and the rollers are pressed together sufficiently to fuse the toner images to said image receptor sheet at ambient temperatures.
Claim 19
Independent Claim
177 words
A method of duplex imaging which comprises creating a first toner image on the surface of an image roller, said image surface having a smoothness in excess of 20 microinch rms and a modulus of elasticity in compression of at least 10 7 PSI; transferring said first toner image to the surface of a transfer roller in rolling contact with said image roller under a compressive load, said transfer roller having a surface layer of an engineering thermoplastic or thermoset material; creating a second toner image on the surface of the image roller; passing an image receptor sheet between said image roller and said transfer roller; and transferring said first toner image from said transfer roller to one side of said image transfer sheet and simultaneously transferring said second toner image from said image roller to an opposite side of said image receptor sheet, wherein the image roller and transfer roller are disposed at an axial skew, and the rollers are pressed together sufficiently to fuse the toner images to said image receptor sheet at ambient temperatures.
Claim 20
Dependent Claim
60 words
The method of claim 16 wherein the image roller has a dielectric surface layer, and wherein the steps of forming the first and second toner images each comprise forming a latent electrostatic image on said dielectric surface layer, and applying toner to said dielectric surface layer to form a toner image as a visible counterpart to the latent electrostatic image.
Claim 21
Dependent Claim
14 words
The method of claim 16 wherein the toner comprises a hydrophobic, single component powder.
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) | 1987-05-15 | 1987-11-14 | 1988-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-15 | 1991-11-14 | 1992-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-15 | 1995-11-14 | 1996-05-15 | $7700.00 | Window Closed / Lapsed |