US4874958A
Expired / Lapsed
US
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Sheet edge detector
Assignee: Xerox Corp
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Filing: 1988-10-04
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Granted: 1989-10-17
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Expires: 2008-10-04
Abstract
Abstract An apparatus which determines the location of an edge of an advancing sheet and discriminates between a hole therein. After the leading edge of the sheet is detected and the sheet has moved a first predetermined distance, the absence or presence of the sheet is sensed for a second predetermined distance. If the sheet is not detected as it moves the second predetermined distance, the control logic indicates that the trailing edge has been detected. In the event the sheet is sensed, the control logic indicates that a hole has been detected and the process is repeated to locate the trailing edge.
Inventors
- 👤 Barbara A. Sampath
- 👤 Richard C. Schenk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:55
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/65; G03G15/6588; B; B65; B65H; B65H7/00; B65H7/02; B65H7/06; B65H7/14; B65H2301/00; B65H2301/30; B65H2301/33; B65H2301/333; B65H2301/3331; B65H2301/33312; B65H2511/00; B65H2511/10; B65H2511/16; B65H2511/20; B65H2511/50; B65H2511/51; B65H2511/514; B65H2511/515; B65H2515/00; B65H2515/60; B65H2553/00; B65H2553/40; B65H2553/41; B65H2553/412; B65H2701/00; B65H2701/10; B65H2701/13; B65H2701/131; B65H2701/1311; B65H2701/1313; G03G2215/00; G03G2215/00362; G03G2215/00367; G03G2215/00417; G03G2215/00421; G03G2215/0043; G03G2215/00438; G03G2215/00443; G03G2215/00523; G03G2215/00535; G03G2215/00611; G03G2215/00616; G03G2215/00687; G03G2215/007; G03G2215/00717; G03G2215/00721
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
36 words
An apparatus for determining the location of an edge of a sheet, including: means for advancing the sheet; and means for distinguishing between the edge of the sheet and a hole in the marginal region thereof.
Claim 2
Independent Claim
36 words
An apparatus for determining the location of an edge of a sheet, including: means for advancing the sheet; and means for distinguishing between the edge of the sheet and a hole in the marginal region thereof.
Claim 3
Dependent Claim
114 words
An apparatus according to claim 1, wherein said distinguishing means includes: control logic; and means, coupled to said control logic, for detecting the sheet, said sheet detecting means sensing the presence of the leading edge of the sheet and, after the sheet advances about a first predetermined distance, the absence of the sheet and transmitting signals corresponding thereto to said control logic, said control logic indicating that the absence of the sheet, after the sheet has advanced about the first predetermined distance, corresponds to the location of the trailing edge of the sheet when said detecting means continues to sense the absence of the sheet as the sheet advances about a second predetermined distance.
Claim 4
Dependent Claim
37 words
An apparatus according to claim 2, wherein said control logic indicates the presence of a hole in the sheet when said detecting means detects the presence of the sheet as the sheet advances the second predetermined distance.
Claim 5
Dependent Claim
22 words
An apparatus according to claim 3, wherein said detecting means includes a photosensor for detecting the presence and absence of the sheet.
Claim 6
Dependent Claim
86 words
An apparatus according to claim 4, wherein said photosensor includes: a light source; and a light detector positioned to receive the light rays from said light source and generating a signal when the light rays from said light source are transmitted thereto, said advancing means being adapted to move the sheet between said light source and said light detector so that, when the sheet is interposed between said light source and said light detector, the light rays from said light source are blocked by the sheet.
Claim 7
Dependent Claim
22 words
An apparatus according to claim 5, wherein: said light source includes a light emitting diode; and said light detector includes a photodiode.
Claim 8
Dependent Claim
52 words
An electrophotographic printing machine of the type in which it is necessary to discriminate between an edge of the copy sheet and a hole therein, wherein the improvement includes: means for advancing the sheet; and means for distinguishing between the edge of the sheet and a hole in the marginal region thereof.
Claim 9
Dependent Claim
52 words
An electrophotographic printing machine of the type in which it is necessary to discriminate between an edge of the copy sheet and a hole therein, wherein the improvement includes: means for advancing the sheet; and means for distinguishing between the edge of the sheet and a hole in the marginal region thereof.
Claim 10
Dependent Claim
115 words
A printing machine according to claim 7, wherein said distinguishing means includes: control logic; and means, coupled to said control logic, for detecting the sheet, said sheet detecting means sensing the presence of the leading edge of the sheet and, after the sheet advances about a first predetermined distance, the absence of the sheet and transmitting signals corresponding thereto to said control logic, said control logic indicating that the absence of the sheet, after the sheet has advanced about the first predetermined distance, corresponds to the location of the trailing edge of the sheet when said detecting means continues to sense the absence of the sheet as the sheet advances about a second predetermined distance.
Claim 11
Dependent Claim
38 words
A printing machine according to claim 8, wherein said control logic indicates the presence of a hole in the sheet when said detecting means detects the presence of the sheet as the sheet advances the second predetermined distance.
Claim 12
Dependent Claim
23 words
A printing machine according to claim 9, wherein said detecting means includes a photosensor for detecting the presence and absence of the sheet.
Claim 13
Dependent Claim
87 words
A printing machine according to claim 10, wherein said photosensor includes: a light source; and a light detector positioned to receive the light rays from said light source and generating a signal when the light rays from said light source are transmitted thereto, said advancing means being adapted to move the sheet between said light source and said light detector so that, when the sheet is interposed between said light source and said light detector, the light rays from said light source are blocked by the sheet.
Claim 14
Dependent Claim
23 words
A printing machine according to claim 11, wherein: said light source includes a light emitting diode; and said light detector includes a photodiode.
Claim 15
Dependent Claim
29 words
A printing machine according to claim 8, further including means, responsive to control logic indicating that the trailing edge of the sheet has been detected, for inverting the sheet.
Claim 16
Independent Claim
32 words
A method of determining the edge of a sheet, including the steps of: advancing the sheet; and distinguishing between the edge of the sheet and a hole in the marginal region thereof.
Claim 17
Independent Claim
32 words
A method of determining the edge of a sheet, including the steps of: advancing the sheet; and distinguishing between the edge of the sheet and a hole in the marginal region thereof.
Claim 18
Dependent Claim
90 words
A method according to claim 14, wherein said step of distinguishing means includes the steps of: detecting the presence of the leading edge of the sheet and, after the sheet advances about a first predetermined distance, the absence of the sheet; and indicating that the absence of the sheet, after the sheet has advanced about the first predetermined distance, corresponds to the location of the trailing edge of the sheet when the absence of the sheet is continued to be sensed as the sheet advances about a second predetermined distance.
Claim 19
Dependent Claim
36 words
A method according to claim 15, wherein said step of indicating indicates the presence of a hole in the sheet when the presence of the sheet is sensed as the sheet advances the second predetermined distance.
Claim 20
Dependent Claim
46 words
A method according to claim 16, wherein said step of detecting includes the steps of: emitting light rays; and generating a signal in response to receiving light rays in the absence of the sheet with the light rays being blocked by the presence of the sheet.
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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) | 1992-10-16 | 1993-04-17 | 1993-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-16 | 1997-04-17 | 1997-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-16 | 2001-04-17 | 2001-10-17 | $7700.00 | Window Closed / Lapsed |