US3884576A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure unit for a copying machine having a variable magnification
Assignee: Ricoh Co Ltd
•
Filing: 1973-12-03
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Granted: 1975-05-20
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Expires: 1993-12-03
Abstract
Abstract In a copying machine having a variable magnification, a plurality of light sources are used to provide an exposure. By controlling the respective timer periods during which the plurality of light sources are energized, the distribution of the exposure is maintained uniform.
Inventors
- 👤 Hideaki Mochimaru
- 👤 Shigeru Suzuki
- 👤 Yohei Ikezu
- 👤 Masao Yaeshima
- 👤 Takeshi Ukai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:14
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/04; G03G15/04036; G03B; G03B27/00; G03B27/72; G03B27/722; G03G15/041
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
142 words
An exposure unit for a copying machine having a variable magnification, the exposure unit comprising a. an optical system, including a lens having an optical axis, for projecting an image of an original to be copied, said optical system being adjustable, to vary the magnification of the image, in a manner effecting lateral displacement of the optical axis of said lens relative to the original; b. a plurality of light sources for illuminating the original, disposed in succession along the path of displacement of said optical axis; and c. means for controlling time periods during which the plurality of light sources are energized such that different ones of said light sources respectively disposed at different locations along said path are energizable for respectively different time periods to compensate for displacement of said optical axis and thereby to maintain a uniform exposure distribution.
Claim 2
Dependent Claim
142 words
An exposure unit for a copying machine having a variable magnification, the exposure unit comprising a. an optical system, including a lens having an optical axis, for projecting an image of an original to be copied, said optical system being adjustable, to vary the magnification of the image, in a manner effecting lateral displacement of the optical axis of said lens relative to the original; b. a plurality of light sources for illuminating the original, disposed in succession along the path of displacement of said optical axis; and c. means for controlling time periods during which the plurality of light sources are energized such that different ones of said light sources respectively disposed at different locations along said path are energizable for respectively different time periods to compensate for displacement of said optical axis and thereby to maintain a uniform exposure distribution.
Claim 3
Dependent Claim
67 words
An exposure unit according to claim 1 in which the time periods during which the plurality of light sources are illuminated are controlled in interlocked relationship with the adjustable optical system of the copying machine such that displacement of said optical axis produces corresponding variation in the respective time periods during which different ones of said light sources are energized, thereby to maintain a uniform exposure distribution.
Claim 4
Dependent Claim
34 words
An exposure unit according to claim 2, further including a plurality of timers which are interlocked with the adjustable optical system, said timers controlling the respective time periods for the plurality of light sources.
Claim 5
Dependent Claim
30 words
An exposure unit according to claim 3, further including an exposure dial which is operative to change the time periods of the plurality of timers without changing the ratio thereof.
Claim 6
Dependent Claim
22 words
An exposure unit according to claim 3 in which the timers initiate their operation by a print switch of the copying machine.
Claim 7
Dependent Claim
44 words
An exposure unit according to claim 1, wherein said controlling means comprises means for varying the respective time periods of energization of different ones of said light sources respectively disposed at different locations along said path in response to displacement of said optical axis.
Claim 8
Dependent Claim
39 words
An exposure unit according to claim 6, further including means for concurrently adjusting the time periods of energization of all of said light sources without varying the relationship between the respective durations of different ones of said time periods.
References Cited (Backward Citations)
US2561535A
Cited
US3227039A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |