EP0077988A2
Expired / Lapsed
EP
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Image density detecting unit for image formation apparatus
Assignee: Toshiba Corp
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Filing: 1982-10-15
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Granted: —
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Expires: 2002-10-15
Abstract
Abstract The invention provides an image density detecting unit for an image formation apparatus, which is made of a transparent optical medium (75), which has a reflecting plate whose section is substantially a quadric surface, and which has a focusing unit for focusing, by means of the reflecting plate, light incident on the transparent optical medium at a predetermined position inside the transparent optical medium.
Inventors
- 👤 Shouji Takano
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 22:52
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/50; G03G15/5025; G03G15/04
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
107 words
An image density detecting unit which is used for an image formation apparatus for forming an electrostatic image on an image carrier by projecting an image of a document and which has detecting means for detecting an amount of light reflected by the document, characterized in that said detecting means comprises a focusing unit (71) which is constituted by a transparent optical medium (75) and which has a light-receiving plane and a reflecting plane of a first reflecting plate (77) having a quadric surface in order to converge incident light (85) in said transparent optical medium within a predetermined range by means of said first reflecting plate.
Claim 2
Dependent Claim
107 words
An image density detecting unit which is used for an image formation apparatus for forming an electrostatic image on an image carrier by projecting an image of a document and which has detecting means for detecting an amount of light reflected by the document, characterized in that said detecting means comprises a focusing unit (71) which is constituted by a transparent optical medium (75) and which has a light-receiving plane and a reflecting plane of a first reflecting plate (77) having a quadric surface in order to converge incident light (85) in said transparent optical medium within a predetermined range by means of said first reflecting plate.
Claim 3
Dependent Claim
15 words
A unit according to claim 1, wherein said quadric surface comprises a parabolic surface (117).
Claim 4
Dependent Claim
14 words
A unit according to claim 1, wherein said quadric surface comprises an elliptical surface.
Claim 5
Dependent Claim
26 words
A unit according to claim 1, wherein a light-receiving element (81) is embedded in said reflecting plate in a position corresponding to the focal point thereof.
Claim 6
Dependent Claim
18 words
A unit according to claim 1, wherein said reflecting plane (126) of said first reflecting plate is discontinuous.
Claim 7
Dependent Claim
55 words
A unit according to claim 2, wherein said transparent optical medium has refractive index of about 1.5, and which has a focal point P1 and a height y O plotted in the X-Y coordinates, and a ratio of the focal point Pl to the height y0 is set in a range of 0.5 to 1.0.
Claim 8
Dependent Claim
36 words
A unit according to any of the preceding claims 1 to 6, wherein a light-receiving width of said focusing unit (71) is equal to or smaller than a minimum document width for said image formation apparatus.
Claim 9
Dependent Claim
29 words
A unit according to claim 1, further comprising means for automatically changing said light-receiving width by arranging a plurality of focusing units (71) in accordance with a document width.
Claim 10
Dependent Claim
52 words
A unit according to claim 8, wherein said document width is detected by said plurality of focusing units to select a proper number of said plurality of focusing units in accordance with said document width, thereby detecting an image density by means of a light-receiving element (81) to obtain an optimal image.
Claim 11
Dependent Claim
23 words
A unit according to claim 1, further comprising a second reflecting plate (79) disposed at the focal point of said first reflecting plate.
Claim 12
Dependent Claim
27 words
A unit according to claim 10, wherein said first and second reflecting plates (77, 79) are disposed at one of inside of said transparent optical medium (75).
Claim 13
Dependent Claim
16 words
A unit according to claim 1, wherein a mask is formed on said light-receiving plane (73).
Claim 14
Dependent Claim
18 words
A unit according to claim 1, wherein slits (al to a10) are formed in said light-receiving plane (73).
Claim 15
Dependent Claim
32 words
A unit according to claim 1, wherein said reflecting plane comprises a quadric surface (111) and has a focal point (113) onto which light incident on said light-receiving plane (73) is converged.
Claim 16
Dependent Claim
32 words
A unit according to claim 1, wherein said reflecting plane comprises a plane of revolution (117) and has a focal point (119) onto which light incident on said light-receiving plane is converged.
Claim 17
Dependent Claim
36 words
A unit according to claim 5, wherein one of a second reflecting plate and a light-receiving element is disposed at a position corresponding to the focal point (125) of said reflecting plane (126) which is discontinuous.
Claim 18
Dependent Claim
24 words
A unit according to claim 10, wherein said first and second reflecting plates are disposed or an outer wall of said transparent optical medium.
References Cited (Backward Citations)
No citation records indexed.
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