US4894682A
Expired / Lapsed
US
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Variable magnification copying apparatus
Assignee: Canon Inc
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Filing: 1987-09-24
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Granted: 1990-01-16
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Expires: 2007-09-24
Abstract
Abstract A variable magnification image forming apparatus includes a photosensitive member, a light source, projecting device for forming and projecting on the photosensitive member an image of the original illuminated by the light source, the projecting device including lens system movable in accordance with a magnification of projection selected, a first limiting member for limiting light rays disposed with a fixed positional relation with respect to the lens system, and a second limiting member for limiting light rays in the lens system, the second limiting member being displaceable in a direction different from a direction of an optical axis of the lens system in accordance with magnification change to change the positional relation with respect to the first limiting member.
Inventors
- 👤 Kazuyuki Kondo
- 👤 Jun Koide
- 👤 Kanji Yano
- 👤 Makoto Tanaka
- 👤 Haruo Tsunoi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:28
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/04; G03G15/041
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
139 words
A variable magnification exposure apparatus, comprising: a light-receiving member; a light source for illuminating an original; projecting means for projecting through a slit an image of an original illuminated by said light source on said light-receiving member, said projecting means including lens means movable in accordance with a magnification of projection selected; a correcting member, disposed in a fixed positional relation to said lens means, for correcting non-uniformity of exposure of said light-receiving member to the projected image along a longitudinal direction of the slit; and an aperture stop member movable in a direction substantially perpendicular to an optical axis of said lens in accordance with the magnification selected; wherein, by movement of said aperture stop member, the relative position between said correcting member and the light rays that pass through said lens means, is maintained with high precision.
Claim 2
Dependent Claim
139 words
A variable magnification exposure apparatus, comprising: a light-receiving member; a light source for illuminating an original; projecting means for projecting through a slit an image of an original illuminated by said light source on said light-receiving member, said projecting means including lens means movable in accordance with a magnification of projection selected; a correcting member, disposed in a fixed positional relation to said lens means, for correcting non-uniformity of exposure of said light-receiving member to the projected image along a longitudinal direction of the slit; and an aperture stop member movable in a direction substantially perpendicular to an optical axis of said lens in accordance with the magnification selected; wherein, by movement of said aperture stop member, the relative position between said correcting member and the light rays that pass through said lens means, is maintained with high precision.
Claim 3
Dependent Claim
26 words
An apparatus according to claim 1, wherein said light source provides luminous intensity distribution wherein it is higher in marginal positions than in a central position.
Claim 4
Dependent Claim
40 words
An apparatus according to claim 1, wherein said correcting means is disposed behind said lens means, and said correcting member does not limit central rays having passed through said lens means when the selected magnification is a predetermined reference magnification.
Claim 5
Dependent Claim
30 words
An apparatus according to claim 3, wherein said correcting means does not limit in a direction of a length of the slit the rays having passed through said lens means.
Claim 6
Dependent Claim
14 words
An apparatus according to claim 3, wherein the reference magnification is a unit magnification.
Claim 7
Dependent Claim
14 words
An apparatus according to claim 3, wherein the reference magnification is an enlarging magnification.
Claim 8
Dependent Claim
20 words
An apparatus according to claim 1, wherein said aperture stop member is disposed at a center of said lens means.
Claim 9
Dependent Claim
52 words
An apparatus according to claim 1, further comprising means for converting a force for driving said lens means into a force in a different direction, means for operatively coupling said converting means with said aperture stop member, wherein said aperture stop member is moved by said converting means and said coupling means.
Claim 10
Dependent Claim
103 words
A variable magnification exposure apparatus, comprising: a light-receiving member; an elongated light source for exposing through a slit said light-receiving member to a light image of an original, said light source extending in a direction parallel to the slit; lens means for imaging the light from said light source on said light-receiving member; a correcting member for correcting non-uniformity, due to magnification change of the exposure on said light receiving member along the longitudinal direction of the slit; and wherein said light source has such a luminous intensity distribution that the luminous intensity is higher in the marginal areas than the central area.
Claim 11
Dependent Claim
103 words
A variable magnification exposure apparatus, comprising: a light-receiving member; an elongated light source for exposing through a slit said light-receiving member to a light image of an original, said light source extending in a direction parallel to the slit; lens means for imaging the light from said light source on said light-receiving member; a correcting member for correcting non-uniformity, due to magnification change of the exposure on said light receiving member along the longitudinal direction of the slit; and wherein said light source has such a luminous intensity distribution that the luminous intensity is higher in the marginal areas than the central area.
Claim 12
Dependent Claim
42 words
An apparatus according to claim 9, wherein said correcting member is partly in an optical path of said lens means, in a degree which is different at the central areas than at the marginal areas along the longitudinal direction of the slit.
Claim 13
Dependent Claim
25 words
An apparatus according to claim 10, wherein said correcting member is more into the optical path at the central area than at the marginal areas.
Claim 14
Dependent Claim
21 words
An apparatus according to claim 9, wherein said correcting member is disposed in a fixed positional relation with said lens means.
Claim 15
Dependent Claim
24 words
An apparatus according to claim 9, wherein said correcting member has correcting portions at both sides of the optical axis of said lens means.
Claim 16
Dependent Claim
104 words
A variable magnification exposure apparatus, comprising: an elongated light source for exposing through a slit a light-receiving member to a light image of an original, said light source extending in a direction parallel to the slit; lens means movable in accordance with a magnification selected; a correcting member for correcting non-uniformity, due to magnification change, of the exposure along the longitudinal direction of the slit said correcting member having correcting portions which are above and below the slit; and wherein said light source has such a luminous intensity distribution that the luminous intensity is higher in the marginal areas than in the central area.
Claim 17
Dependent Claim
104 words
A variable magnification exposure apparatus, comprising: an elongated light source for exposing through a slit a light-receiving member to a light image of an original, said light source extending in a direction parallel to the slit; lens means movable in accordance with a magnification selected; a correcting member for correcting non-uniformity, due to magnification change, of the exposure along the longitudinal direction of the slit said correcting member having correcting portions which are above and below the slit; and wherein said light source has such a luminous intensity distribution that the luminous intensity is higher in the marginal areas than in the central area.
Claim 18
Dependent Claim
14 words
An apparatus according to claim 14, wherein said correcting portions have different correcting functions.
Claim 19
Dependent Claim
43 words
An apparatus according to claim 15, wherein one of said correcting portions blocks more of the rays at the end area, than at the central area, and the other blocks more of the rays at the central area than at the marginal areas.
Claim 20
Dependent Claim
66 words
A variable magnification copying apparatus, comprising: zoom lens means for changing its focal length in accordance with a magnification selected; a movable member movable in accordance with the selected magnification to limit light rays; a first cam for changing the focal length of said zoom lens; a second cam for moving said movable member; and wherein said first and second cams are formed on one member.
Claim 21
Dependent Claim
66 words
A variable magnification copying apparatus, comprising: zoom lens means for changing its focal length in accordance with a magnification selected; a movable member movable in accordance with the selected magnification to limit light rays; a first cam for changing the focal length of said zoom lens; a second cam for moving said movable member; and wherein said first and second cams are formed on one member.
Claim 22
Dependent Claim
15 words
An apparatus according to claim 17, wherein said correcting member is an aperture stop member.
Claim 23
Dependent Claim
15 words
An apparatus according to claim 17, wherein said first cam has a curved cam surface.
Claim 24
Dependent Claim
33 words
An apparatus according to claim 17, wherein said second cam has an inclined cam surface, and said correcting member is moved by said second cam in a direction perpendicular to the optical axis.
Claim 25
Dependent Claim
24 words
An apparatus according to claim 17, wherein said member having the first and second cams is guided by a cam for moving the lens.
Claim 26
Dependent Claim
93 words
A variable magnification exposure apparatus, comprising: a light source for exposing through a slit a light-receiving member to a light image of an original; lens means movable in accordance with an image magnification selected; a correcting member for correcting non-uniformity of the exposure along a longitudinal direction of the slit, said correcting member maintaining a constant distance from said lens means in a direction of an optical axis of said lens means independently of the magnification selected, wherein said correcting member permits light rays to pass without limitation thereby at a reference magnification.
Claim 27
Dependent Claim
93 words
A variable magnification exposure apparatus, comprising: a light source for exposing through a slit a light-receiving member to a light image of an original; lens means movable in accordance with an image magnification selected; a correcting member for correcting non-uniformity of the exposure along a longitudinal direction of the slit, said correcting member maintaining a constant distance from said lens means in a direction of an optical axis of said lens means independently of the magnification selected, wherein said correcting member permits light rays to pass without limitation thereby at a reference magnification.
Claim 28
Dependent Claim
14 words
An apparatus according to claim 22, wherein said reference magnification is a unit magnification.
Claim 29
Dependent Claim
14 words
An apparatus according to claim 22, wherein said reference magnification is an enlarging magnification.
Claim 30
Dependent Claim
21 words
An apparatus according to claim 22, wherein said light source is brighter at its marginal areas than at its central area.
Claim 31
Dependent Claim
42 words
An apparatus according to claim 22, wherein said correcting member is partly in an optical path of said lens means in a degree which is different at a central area than at an end area along a longitudinal direction of the slit.
Claim 32
Dependent Claim
29 words
An apparatus according to claim 26, wherein said correcting member is more into the optical path of the lens means at the central area than at the marginal areas.
Claim 33
Dependent Claim
20 words
An apparatus according to claim 22, wherein said correcting member has correcting portions which are above and below the slit.
Claim 34
Dependent Claim
14 words
An apparatus according to claim 28, wherein said correcting portions have different correcting functions.
Claim 35
Dependent Claim
43 words
An apparatus according to claim 29, wherein one of said correcting portions blocks more of the rays at the marginal portions than at the central area, and the other blocks more of the rays at the central area than at the marginal area.
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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) | 1993-01-15 | 1993-07-17 | 1994-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-15 | 1997-07-17 | 1998-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-15 | 2001-07-17 | 2002-01-16 | $7700.00 | Window Closed / Lapsed |