US4892426A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Paper movement monitor
Assignee: Unisys Corp
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Filing: 1988-06-30
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Granted: 1990-01-09
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Expires: 2008-06-30
Abstract
Abstract A monitor (18,26,28) monitors movement of paper (12) through a printer (16). The paper movement sensors (18,26) comprise one central wheel (70) or a pair of spaced edge wheels (158) each operating an individual photo-optic wheel (164,76). By counting pulses from the photo-optic wheels (76,164) monitor logic (28) determines conditions of jam, over-feeding and skew within the printer (16) both on an instantaneous and on a short term cumulative basis. The system self-calibrates through an initializing routine and later, continuously during operation. Paper movement sensors (18,26) are provided in dust-protected housings which can be chained together to provide monitoring facilities at many points.
Inventors
- 👤 David Steele
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:36
CPC Classifications
B; B41; B41J; B41J15/00; B41J15/04; B41J15/06
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
75 words
An apparatus for monitoring movement of paper in a printer, said apparatus comprising a first movement sensor operative to engage paper in a printer at a first point and operative to detect the distance moved by the paper at said first point between successive lines of printing, said apparatus providing indication of a paper feed error if said distance of movement detected by said first sensor does not lie within first and second predetermined limits.
Claim 2
Independent Claim
75 words
An apparatus for monitoring movement of paper in a printer, said apparatus comprising a first movement sensor operative to engage paper in a printer at a first point and operative to detect the distance moved by the paper at said first point between successive lines of printing, said apparatus providing indication of a paper feed error if said distance of movement detected by said first sensor does not lie within first and second predetermined limits.
Claim 3
Dependent Claim
93 words
An apparatus according to claim 1 including a second movement sensor operative to engage paper in a printer at a second point and operative to detect the distance moved by the paper at said second point between successive lines of printing, said apparatus being operative to make a first sum of the distance detected by said first sensor, to make a second sum of the distance detected by said second sensor, and to provide indication of paper accumulation if the difference between said first sum and said second sum exceeds a predetermined magnitude.
Claim 4
Dependent Claim
123 words
An apparatus according to claim 2 wherein said first sensor comprises first rolling means for rolling on advancing paper and a first rotation detection means for providing output indicative of angular movement of said first rolling means; wherein said second sensor comprises second rolling means for rolling on advancing paper and a second rotation detection means for providing output indicative of angular movement of said second rolling means; and wherein said apparatus self-calibrates by making a sum of the output of said first rotation detection means, by making a sum of the output of said second rotation detection means; and by finding the ratio between the sums of said outputs of said first and second rotation detection means to establish an advance ratio.
Claim 5
Dependent Claim
47 words
An apparatus according to claim 3 further adapted to multiply said sum of said output of said first or said second rotation detection means by said advance ratio to normalize said outputs of said first rotation detection means with said output of said second rotation detection means.
Claim 6
Dependent Claim
35 words
An apparatus according to claim 3 wherein said first rolling means comprises a wheel, and wherein said first rotation detection means comprises a first wheel rotation detector coupled to monitor rotation of said first wheel.
Claim 7
Dependent Claim
36 words
An apparatus according to claim 3 wherein said second rolling means comprises a second wheel, and wherein said second rotation detection means comprises a second wheel rotation detector coupled to monitor rotation of said second wheel.
Claim 8
Dependent Claim
104 words
An apparatus according to claim 3 operative to form a long term value of said advance ratio based on paper movement through a first number of lines of printing, operative to form a short term value of said advance ratio based on paper movement through a second number of lines of printing, less than said first number of lines of printing, and operative to indicate a problem with paper movement between said first and second sensors if the ratio between said long term value of said advance ratio and said short term value of said advance ratio falls outside predetermined upper and lower values.
Claim 9
Dependent Claim
113 words
An apparatus according to claim 3 operative to form a long term sum of said distance detected by said first sensor based on paper movement through a first number of lines of printing; operative to form a short term sum of said distance detected by said first sensor based on paper movement through a second number of lines of printing, less than said first number of lines of printing; and operative to indicate a paper movement fault if the ratio between said long term value of said distance detected by said first sensor and said short term value of said distance detected by said first sensor falls outside predetermined upper and lower values.
Claim 10
Dependent Claim
113 words
An apparatus according to claim 7 operative to form a long term sum of said distance detected by said second sensor based on paper movement through a first number of lines of printing; operative to form a short term sum of said distance detected by said second sensor based on paper movement through a second number of lines of printing, less than said first number of lines of printing; and operative to indicate a paper movement fault if the ratio between said long term value of said distance detected by said second sensor and said short term value of said distance detected by said second sensor falls outside predetermined upper and lower values.
Claim 11
Dependent Claim
72 words
An apparatus according to claim 3 wherein said first rolling means comprises: first and second edge wheels, spaced transversely to the direction of paper movement, and each operative to engage paper proximately to a respective edge; and a first edge wheel rotation detector for providing output indicative of rotation of said first edge wheel and a second edge wheel rotation detector for providing output indicative of rotation of said second edge wheel.
Claim 12
Dependent Claim
95 words
An apparatus according to claim 10 operative to make a sum of rotation indicated by said first edge wheel rotation detector, and operative to make a sum of rotation indicated by said second edge wheel rotation detector and operative to take the ratio between said sum of said output of said first edge wheel rotation detector and said sum of said output of said second edge wheel rotation detector to form a first edge ratio, and therefor operative to multiply an output of said first or second edge wheel rotation detectors to equalize sensitivity therebetween.
Claim 13
Dependent Claim
46 words
An apparatus according to claim 11 operative to provide, as said output of said rotation detection means, the mean value of said sum of said output of said first edge wheel rotation detector and said sum of said output of said second edge wheel rotation detector.
Claim 14
Dependent Claim
46 words
An apparatus according to claim 11, operative to provide output indicative of paper skew if the difference between said sum of said output of said first edge wheel rotation detector and said sum of said output of said second edge wheel rotation detector exceeds predetermined limits.
Claim 15
Dependent Claim
99 words
An apparatus according to claim 11 operative to form a long term value of said first edge ratio based on paper movement through a first number of lines of printing, operative to form a short term value of said first edge ratio based on paper movement through a second number of lines of printing less than said first number of lines of printing; and operative to indicate paper skew if the ratio between said long term value of said first edge ratio and said short term value of said first edge ratio falls outside predetermined upper and lower values.
Claim 16
Dependent Claim
81 words
An apparatus according to claim 3 wherein said second rolling means comprises third and fourth edge wheels spaced transversely to the direction of paper movement each operative to engage paper proximately to a respective edge of the paper; and wherein said second rotation detection means comprises a third edge wheel rotation detector for providing output indicative of rotation of said third edge wheel and a fourth edge wheel rotation detector for providing output indicative of rotation of said fourth edge wheel.
Claim 17
Dependent Claim
37 words
An apparatus according to claim 15 operative to make a sum of rotation indicated by said third edge wheel rotation detector, and operative to make a sum of rotation indicated by said fourth edge wheel rotation detector.
Claim 18
Dependent Claim
63 words
An apparatus according to claim 16 operative to take the ratio between said sum of said output of said third edge wheel rotation detector and said sum of said output of said fourth edge wheel rotation detector to form a second edge ratio, and thereafter to multiply an output of said third or said fourth edge wheel rotation detectors to equalize sensitivity there-between.
Claim 19
Dependent Claim
87 words
An apparatus according to claim 17 operative to provide, as said output of said rotation detection means, the mean value of said sum of said output of said third edge wheel rotation detector and said sum of said output of said fourth edge wheel rotation detector and operative to provide output indicative of paper skew if the difference between said sum of said output of said third edge wheel rotation detector and said sum of said output of said fourth edge wheel rotation detector exceeds predetermined limits.
Claim 20
Dependent Claim
99 words
An apparatus according to claim 17 operative to form a long term value of said second edge ratio based on paper movement through a first number of lines of printing, operative to form a short term value of said second edge ratio based on paper movement through a second number of lines of printing, less than said first number of lines of printing; and operative to indicate paper skew if the ratio between said long term value of said second edge ratio and said short term value of said second edge ratio falls outside predetermined upper and lower values.
Claim 21
Dependent Claim
36 words
An apparatus according to claim 7 wherein said long term and said short term values of said advance ratio are initially established in a calibration routine involving movement of paper through said first number of lines.
Claim 22
Dependent Claim
40 words
An apparatus according to claim 8 wherein said long term and said short term sums of said movement detected by said first sensor are initially established in a calibration routine involving movement of paper through said first number of lines.
Claim 23
Dependent Claim
40 words
An apparatus according to claim 9, wherein said long term and said short term sums of said movement detected by said second sensor are initially established in a calibration routine involving movement of paper through said first number of lines.
Claim 24
Dependent Claim
37 words
An apparatus according to claim 14 wherein said long term and said short term values of said first edge ratio are initially established in a calibration routine involving movement of paper through said first number of lines.
Claim 25
Dependent Claim
37 words
An apparatus according to claim 19, wherein said long term and said short term values of said second edge ratio are initially established in a calibration routine involving movement of paper through said first number of lines.
Claim 26
Dependent Claim
41 words
An apparatus according to claim 2 wherein said first sensor comprises a first sensor housing for sitting astride the advancing paper in a printer, said first sensor housing comprising a pair of support arms for engaging either side of a printer.
Claim 27
Dependent Claim
48 words
An apparatus according to claim 25 wherein said second sensor comprises a second sensor housing for sitting astride the advancing paper, said second sensor housing comprising a pair of support arms for engaging said first sensor housing for said first sensor housing to support said second sensor housing.
Claim 28
Dependent Claim
20 words
An apparatus according to claim 26 wherein said second sensor housing is identical in outline to said first sensor housing.
References Cited (Backward Citations)
US3081700A
Cited
US3147898A
Cited
US3323700A
Cited
US3521880A
Cited
US3858052A
Cited
US3917142A
Cited
US4212419A
Cited
DE2847619A1
Cited
GB2017058A
Cited
US4216482A
Cited
US4370665A
Cited
US4545031A
Cited
US4530613A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-01-08 | 1993-07-10 | 1994-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-08 | 1997-07-10 | 1998-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-08 | 2001-07-10 | 2002-01-09 | $7700.00 | Window Closed / Lapsed |