US3892480A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure device for copying machine and the like
Assignee: Fujifilm Business Innovation Corp
•
Filing: 1973-11-21
•
Granted: 1975-07-01
•
Expires: 1993-11-21
Abstract
Abstract In an electrostatic copying machine where an original of a first size positioned on a transparent platen is illuminated by a light source and the image thereof is reflected onto a uniformly charged photosensitive layer to form a latent electrostatic image on the photosensitive layer, which is subsequently toner developed, the improvement of preventing toner deposition at a predetermined marginal area of the photosensitive layer when an original of a second size smaller than the first size is copied by the machine, the predetermined marginal area corresponding to the excess area of the first size original with respect to the second size original, the improvement comprising means for reducing the area illuminated by the light source to an area substantially the same as that of the second size original and for exposing the predetermined marginal area of the photosensitive layer in the same manner as the non-image areas of the latent electrostatic image so that when the image is toner developed, toner will deposit only on the image areas.
Inventors
- 👤 Ryuzo Okada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:42
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/04; G03G15/045; G03G15/047; G03G2215/00; G03G2215/04; G03G2215/0429; G03G2215/0431; G03G2215/0434; G03G2215/0436; G03G2215/0446; G03G2215/0448; G03G2215/0463
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
281 words
In an electrostatic copying machine where an original of a first size positioned on a transparent platen is illuminated by a light source and the image thereof is reflected onto a uniformly charged photosensitive layer to form a latent electrostatic image on the photosensitive layer, which is subsequently toner developed, the improvement of preventing toner deposition at a predetermined, marginal area of said photosensitive layer when an original of a second size smaller than said first size is copied by said machine, the predetermined marginal area corresponding to the excess area of said first size original with respect to said second size origianl, the improvement comprising a plate movably mounted with respect to said light source, said plate including an opening therein and moving means for moving said plate to: (1) a first position interposed between said light source and said transparent platen when said second size is copied, and (2) to a second position not interposed between said light source and said transparent platen when said first size original is copied, the size of the opening in said plate being such that it reduces the area illuminated by said light source to substantially that of said second size original when said plate is in said first position, the remaining light from said light source being affected by the area of said plate adjacent said opening to prevent toner deposition at said predetermined marginal area of the photosensitive lAyer by causing the predetermined marginal area of said photosensitive layer to be exposed in the same manner as the non-image areas of said latent electrostatic image so that when said image is toner developed, toner will deposit only on the image areas.
Claim 2
Dependent Claim
281 words
In an electrostatic copying machine where an original of a first size positioned on a transparent platen is illuminated by a light source and the image thereof is reflected onto a uniformly charged photosensitive layer to form a latent electrostatic image on the photosensitive layer, which is subsequently toner developed, the improvement of preventing toner deposition at a predetermined, marginal area of said photosensitive layer when an original of a second size smaller than said first size is copied by said machine, the predetermined marginal area corresponding to the excess area of said first size original with respect to said second size origianl, the improvement comprising a plate movably mounted with respect to said light source, said plate including an opening therein and moving means for moving said plate to: (1) a first position interposed between said light source and said transparent platen when said second size is copied, and (2) to a second position not interposed between said light source and said transparent platen when said first size original is copied, the size of the opening in said plate being such that it reduces the area illuminated by said light source to substantially that of said second size original when said plate is in said first position, the remaining light from said light source being affected by the area of said plate adjacent said opening to prevent toner deposition at said predetermined marginal area of the photosensitive lAyer by causing the predetermined marginal area of said photosensitive layer to be exposed in the same manner as the non-image areas of said latent electrostatic image so that when said image is toner developed, toner will deposit only on the image areas.
Claim 3
Dependent Claim
71 words
The improvement as in claim 1 where said light source comprises at least one elongated tube movably mounted with respect to said transparent platen for scanning an original, the opening in said plate being such that when said plate is interposed between said elongated tube and said platen, both ends of said tube are covered thereby reducing the area illuminated by said tube to approximately that of said second size original.
Claim 4
Dependent Claim
91 words
The improvement as in claim 2 where light tube is mounted within a light housing and said plate includes means for removably attaching said plate to said housing, said moving means moving said plate (1) to said first position to attach the plate to the housing so that said plate will move with the housing as the light source scans the second size original and (2) to said second position to remove the plate from the housing so that only the light source moves as it scans the first size document.
Claim 5
Dependent Claim
28 words
The improvement as in claim 1 where said first size original is B4 size (substantially legal size) and said second size original is A4 size (substantially letter size).
Claim 6
Dependent Claim
168 words
The improvement as in claim 1 where a positive copy is obtained from a positive original and said improvement comprises a light reflecting plate movably mounted with respect to said light source, said reflecting plate including an opening therein and means for moving said reflecting plate to (1) a first position interposed between said light source and said transparent platen when said second size original is copied and (2) to a second position not interposed between said light source and said transparent platen when said first size original is copied, the size of the opening in said reflecting plate being such that it reduces the area illuminated by said light source to substantially that of said second size original, the remaining light from said light source being reflected by said reflecting plate onto said photosensitive layer to discharge the charge at said predetermined marginal area and thereby prevent toner deposition thereat, said toner being charged to a polarity opposite to that of the charge on said photosensitive layer.
Claim 7
Dependent Claim
169 words
The improvement as in claim 1 where a positive copy is obtained from a negative original and said improvement comprises a light absorbing plate movably mounted with respect to said light source, said absorbing plate including an opening therein and means for moving said absorbing plate to (1) a first position interposed between said light source and said transparent platen when said second size original is copied and (2) to a second position not interposed between said light source and said transparent platen when said first size original is copied, the size of the opening in said reflecting plate being such that it reduces the area illuminated by said light source to substantially that of said second size original, the remaining light from said light source being absorbed by said absorbing plate to prevent the discharge of charge at said predetermined marginal area of the photosensitive layer and thereby prevent toner deposition thereat, said toner being charged to the same polarity as of the charge on said photosensitive layer.
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) | 1978-06-30 | 1978-12-30 | 1979-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-30 | 1982-12-30 | 1983-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-30 | 1986-12-30 | 1987-07-01 | $7700.00 | Window Closed / Lapsed |