Patent US4083632A successfully refreshed from Google Patents.
US4083632A
Expired / Lapsed
US
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Multi-frequency screen
Assignee: Xerox Corp
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Filing: 1976-04-05
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Granted: 1978-04-11
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Expires: 1996-04-05
Abstract
Abstract A half-tone screen in which a substantially transparent substrate has a plurality of opaque regions disposed thereon. The opaque regions are arranged in at least a high frequency repetitive pattern and a low frequency repetitive pattern. This type of screen may be employed to modulate the light image of a color transparency being reproduced by an electrophotographic printing machine.
Inventors
- 👤 Louis D. Mailloux
- 👤 James E. Bollman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:32
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/04; G03G15/04027
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
122 words
An electrophotographic printing machine for reproducing a color transparency, including: a photoconductive member; means for charging at least a portion of said photoconductive member to a substantially uniform potential; a receiving member spaced from said photoconductive member; a screen member mounted on said receiving member, said screen member comprising a low frequency repetitive pattern of opaque regions and a high frequency repetitive pattern of opaque regions extending across said screen member and being superimposed over one another with each opaque region being substantially identical to one another; and means for projecting a light image of the color transparency through said screen member onto the charged portion of said photoconductive member discharging selectively the charge to record thereon a modulated electrostatic latent image.
Claim 2
Dependent Claim
122 words
An electrophotographic printing machine for reproducing a color transparency, including: a photoconductive member; means for charging at least a portion of said photoconductive member to a substantially uniform potential; a receiving member spaced from said photoconductive member; a screen member mounted on said receiving member, said screen member comprising a low frequency repetitive pattern of opaque regions and a high frequency repetitive pattern of opaque regions extending across said screen member and being superimposed over one another with each opaque region being substantially identical to one another; and means for projecting a light image of the color transparency through said screen member onto the charged portion of said photoconductive member discharging selectively the charge to record thereon a modulated electrostatic latent image.
Claim 3
Dependent Claim
62 words
A printing machine as recited in claim 1, further including: a composition frame disposed on said receiving member; and means for exposing the charged portion of said photoconductive member to a light image of said composition frame recording thereon a combined electrostatic latent image comprising the electrostatic latent image of the color transparency and the electrostatic latent image of said composition frame.
Claim 4
Dependent Claim
72 words
A printing machine as recited in claim 2, wherein said exposing means includes: a light source arranged to illuminate said composition frame on said receiving member; and a lens positioned to receive the light rays transmitted from said composition frame and the light image of the color transparency, said lens transmitting the low frequency components of the light image passing through said screen member and not transmitting the high frequency component therethrough.
Claim 5
Dependent Claim
23 words
A printing machine as recited in claim 1, wherein said screen member includes a substantially transparent substrate having the opaque regions disposed thereon.
Claim 6
Dependent Claim
15 words
A printing machine as recited in claim 4, wherein the opque regions include spaced dots.
Claim 7
Dependent Claim
33 words
A printing machine as recited in claim 5, wherein the dots include a pattern of first dots of a maximum area and a pattern of second dots of a lesser area disposed thereabout.
Claim 8
Dependent Claim
35 words
A printing machine as recited in claim 5, wherein said dots include a low frequency repetitive pattern of about 85 dots per inch and a high frequency repetitive pattern of about 300 dots per inch.
Claim 9
Dependent Claim
42 words
A printing machine as recited in claim 1, further including means for filtering the light image to form a single color light image which irradiates the charged portion of said photoconductive member to record thereon a modulated single color electrostatic latent image.
Claim 10
Dependent Claim
37 words
A printing machine as recited in claim 1, wherein said receiving member includes: a substantially transparent platen member having said screen member disposed thereon; and a field lens interposed between said platen member and said screen member.
Claim 11
Dependent Claim
19 words
A printing machine as recited in claim 9, wherein said field lens preferably includes about 200 gratings per inch.
Claim 12
Dependent Claim
55 words
A half-tone screen, including: a substantially transparent substrate; and a plurality of opaque regions disposed on said substrate, said opaque regions being arranged in a high frequency repetitive pattern and a low frequency repetitive pattern extending across said substrate and being superimposed over one another with each opaque region being substantially identical to one another.
Claim 13
Dependent Claim
55 words
A half-tone screen, including: a substantially transparent substrate; and a plurality of opaque regions disposed on said substrate, said opaque regions being arranged in a high frequency repetitive pattern and a low frequency repetitive pattern extending across said substrate and being superimposed over one another with each opaque region being substantially identical to one another.
Claim 14
Dependent Claim
14 words
A screen as recited in claim 11, wherein said opaque regions include spaced dots.
Claim 15
Dependent Claim
31 words
A screen as recited in claim 12, wherein the dots include a pattern of first dots of maximum area and a pattern of second dots of a lesser area disposed thereabout.
Claim 16
Dependent Claim
34 words
A screen as recited in claim 12, wherein said dots include a low frequency repetitive pattern of about 85 dots per inch and a high frequency repetitive pattern of about 300 dots per inch.
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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) | 1981-04-10 | 1981-10-10 | 1982-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-10 | 1985-10-10 | 1986-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-10 | 1989-10-10 | 1990-04-11 | $7700.00 | Window Closed / Lapsed |