US4926358A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for controlling curls of a paper
Assignee: Ricoh Co Ltd
•
Filing: 1988-05-20
•
Granted: 1990-05-15
•
Expires: 2008-05-20
Abstract
Abstract A curl control system applicable to an electrophotographic copier for sensing the conditions of curls of a paper being transported and correcting the curls includes a curl sensing device and a curl correcting device. Two distance sensor units illuminate the paper and receive a reflection from the paper to sense the amount and direction of curl of the paper. A paper size sensor is provided for sensing the size of the paper. The curl correcting device corrects the curls on the basis of the amount and direction of curl sensed. The curl correcting device may be implemented in the device in many fashions.
Inventors
- 👤 Tatsuo Tani
- 👤 Hiroshi Yokoyama
- 👤 Shoji Hayashi
- 👤 Takashi Murofushi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:59
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/65; G03G15/6555; G03G15/6573; G03G15/6576; B; B41; B41J; B41J11/00; B41J11/0005; G03G15/20; G03G15/2003; G03G15/2014; G03G15/2064; G03G2215/00; G03G2215/00362; G03G2215/00367; G03G2215/00371; G03G2215/00379; G03G2215/00383; G03G2215/00409; G03G2215/00417; G03G2215/00421; G03G2215/00535; G03G2215/00611; G03G2215/00616; G03G2215/00662; G03G2215/00666; G03G2215/0067; G03G2215/00789; G03G2215/00822; G03G2215/00827
Claims Analysis
Total Claims: 64
Claim 1
Independent Claim
53 words
A curl control system, for controlling curl of a paper which is applicable to an image forming apparatus, comprising: curl sensing means for sensing a curl of the paper; and curl correcting means for correcting the curl, sensed by said curl sensing means on the basis of the sensed conditions of any curl.
Claim 2
Dependent Claim
53 words
A curl control system, for controlling curl of a paper which is applicable to an image forming apparatus, comprising: curl sensing means for sensing a curl of the paper; and curl correcting means for correcting the curl, sensed by said curl sensing means on the basis of the sensed conditions of any curl.
Claim 3
Dependent Claim
30 words
A curl control system as claimed in claim 1, wherein said curl sensing means comprises distance sensor means for sensing an amount and a direction of curl of the paper.
Claim 4
Dependent Claim
76 words
A curl control system as claimed in claim 2, wherein said curl sensing means further comprises: paper transport means, disposed on a paper transport path, which is defined in the image forming apparatus; paper support means, disposed on said paper transport path, for supporting at least a part of the paper; and wherein said distance sensor means is positioned above and at a predetermined distance from the paper which is supported by said paper support means.
Claim 5
Dependent Claim
40 words
A curl control system as claimed in claim 3, wherein said paper support means has a part whose width is smaller than a width of the paper and a part whose width is greater than the width of the paper.
Claim 6
Dependent Claim
35 words
A curl control system as claimed in claim 3, wherein said curl sensing means further comprises paper size sensor means for measuring a size of the paper which is transported along the paper transport path.
Claim 7
Dependent Claim
46 words
A curl control system as claimed in claim 5, wherein said distance sensor means comprises at least two distance sensors each being constituted by light emitting means for emitting light toward the paper and light-sensitive means for receiving the light which is reflected by the paper.
Claim 8
Dependent Claim
27 words
A curl control system as claimed in claim 6, wherein said curl sensing means further comprises distance sensor positioning means for moving and positioning said distance sensors.
Claim 9
Dependent Claim
53 words
A curl control system as claimed in claim 7, wherein said curl sensing means further comprises control means for controlling said distance sensor positioning means such that a distance between said distance sensors is adjusted on the basis of the size of the paper which is measured by said paper size sensor means.
Claim 10
Dependent Claim
63 words
A curl control system as claimed in claim 8, wherein said control means comprises allowable curl level setting means for setting an allowable curl level, excess curl detector means for reporting an excess curl when the amount of curl detected by said distance sensor means is above the allowable curl level, and display means for displaying a signal indicative of the excess curl.
Claim 11
Dependent Claim
34 words
A curl control system as claimed in claim 9, wherein said control means is constructed to disenable a part of various processing units of the image forming apparatus when the excess curl is detected.
Claim 12
Dependent Claim
113 words
A curl control system as claimed in claim 1, wherein said curl correcting means comprises: first transport means, for receiving the paper being transported along a paper transport path, which is defined in the image forming apparatus; path selector means causing the paper received by said first transport means to follow either one of a first and a second path depending upon conditions of the curl which is sensed by said curl sensing means; stress applying means disposed on said first and second paths for correcting the curl of the paper by applying a stress to the paper, and second transport means for discharging the paper to which a stress has been applied.
Claim 13
Dependent Claim
26 words
A curl control system as claimed in claim 11, wherein said first transport means and said second transport means each comprises a pair of transport rollers.
Claim 14
Dependent Claim
47 words
A curl control system as claimed in claim 12, wherein said path selector means comprises a selector pawl for guiding the paper which is received by said transport roller pair to one of the first path and the second paths depending upon the conditions of the curl.
Claim 15
Dependent Claim
72 words
A curl control system as claimed in claim 13, wherein said stress applying means comprises a main roller rotatably supported by a support member, a first subroller held in contact with said main roller for applying a stress to the paper which is fed to the first path, and a second subroller held in contact with said main roller for applying stress to the paper which is fed to the second path.
Claim 16
Dependent Claim
18 words
A curl control system as claimed in claim 14, wherein a heater is built in said main roller.
Claim 17
Dependent Claim
32 words
A curl control system as claimed in claim 14, wherein said stress applying means further comprises a support member for rotatably supporting said main roller, said first subroller, and said second subroller.
Claim 18
Dependent Claim
25 words
A curl control system as claimed in claim 16, wherein said stress applying means further comprises support member displacing means for displacing said support member.
Claim 19
Dependent Claim
53 words
A curl control system as claimed in claim 1, wherein said curl correcting means comprises humidity adjusting means for adjusting, on the basis of conditions of the curl sensed by said curl sensing means, humidity of an ambience around the paper which is laid on a paper feeder of the image forming apparatus.
Claim 20
Dependent Claim
32 words
A curl control system as claimed in claim 18, wherein said humidity adjusting means comprises at least one of humidifier means for humidifying the ambience and dehumidifying means for dehumidifying the ambience.
Claim 21
Dependent Claim
26 words
A curl control system as claimed in claim 19, wherein said dehumidifying means comprises both a heater and a humdifying means which comprises an ultrasonic humidifier.
Claim 22
Dependent Claim
31 words
A curl control system as claimed in claim 19, wherein said humidity adjusting means further comprises control means for controlling operations of either of a humidifying means and a dehumidifying means.
Claim 23
Dependent Claim
69 words
A curl control system as claimed in claim 21, wherein said control means comprises, allowable curl level setting means for setting an allowable curl level, excess curl detector means for reporting an excess curl when the amount of curl sensed is above the allowable curl level, and drive control means responsive to the excess curl for selectively activating and deactivating either of a humidifying means and a dehumidifying means.
Claim 24
Dependent Claim
67 words
A curl control system as claimed in claim 1, wherein said curl correcting means comprises: guide means for guiding the paper, to a transfer station and to a photoconductive element of the image forming apparatus; and guide means positioning means for adjusting a position of said guide means on the basis of conditions of the curl of the paper which is sensed by said curl sensing means.
Claim 25
Dependent Claim
17 words
A curl control system as claimed in claim 23, wherein said guide means comprises a guide plate.
Claim 26
Dependent Claim
20 words
A curl control system as claimed in claim 24, wherein said guide is made up of a plurality of segments.
Claim 27
Dependent Claim
52 words
A curl control system as claimed in claim 24, wherein said guide means positioning means comprises at least one of distance adjusting means for changing a distance between said guide plate and the photoconductive element and angle adjusting means for changing an angle of said guide plate relative to the photoconductive element.
Claim 28
Dependent Claim
42 words
A curl control system as claimed in claim 26, wherein said angle adjusting means comprises an eccentric cam rotatable in pressing contact with said guide plate on the basis of the amount of curl which is sensed by said curl sensing means.
Claim 29
Dependent Claim
31 words
A curl control system as claimed in claim 26, wherein said distance adjusting means comprises solenoid means for displacing said guide plate on the basis of the amount of curl sensed.
Claim 30
Dependent Claim
63 words
A curl control system as claimed in claim 1, wherein said curl correcting means comprises: current control means for controlling, on the basis of a signal indicative of the conditions of the curl which is sensed by said curl sensing means a transfer current caused to flow by a transfer charger, which is provided at a transfer station of the image forming apparatus.
Claim 31
Dependent Claim
31 words
A curl control system as claimed in claim 29, wherein said current control means comprises adjusting means for changing a distance between a casing of the transfer charger and charge wires.
Claim 32
Dependent Claim
28 words
A curl control system as claimed in claim 30, wherein said adjusting means comprises movable members which are individually movable on and along opposite walls of the casing.
Claim 33
Dependent Claim
17 words
A curl control system as claimed in claim 31, wherein said movable members comprises four conductive members.
Claim 34
Dependent Claim
63 words
A curl control system as claimed in claim 1, wherein said curl correcting means comprises: current control means for controlling, on the basis of a signal indicative of the conditions of the curl which is sensed by said curl sensing means, a separation current caused to flow by a separation charger which is provided at a transfer station of the image forming apparatus.
Claim 35
Dependent Claim
31 words
A curl control system as claimed in claim 33, wherein said current control means comprises adjusting means for changing a distance between a casing of the separation charger and charge wires.
Claim 36
Dependent Claim
32 words
A curl control system as claimed in claim 34, wherein said adjusting means comprises movable members which are movable on and along opposite side walls of the casing of the separation charger.
Claim 37
Dependent Claim
17 words
A curl control system as claimed in claim 35, wherein said movable members comprise four conductive members.
Claim 38
Dependent Claim
67 words
A curl control system as claimed in claim 1, wherein said curl correcting means comprises: pawl positioning means for controlling, on the basis of a signal indicative of the conditions of the curl which is sensed by said curl sensing means, adjusting a position of a pawl which separates the paper from a photoconductive element after image transfer at a transfer station of the image forming apparatus.
Claim 39
Dependent Claim
64 words
A curl control system as claimed in claim 37, wherein said curl correcting means further comprises allowable curl level setting means for setting an allowable curl level, excess curl detector means for reporting an excess curl when the curl sensed is above the allowable curl level, and control means for driving said pawl positioning means in response to a signal indicative of any curl.
Claim 40
Dependent Claim
44 words
A curl control system as claimed in claim 1, wherein said curl correcting means comprises: suction adjusting means for, on the basis of a signal indicative of the conditions of the curl sensed, adjusting a suction which is exerted by a paper transport mechanism.
Claim 41
Dependent Claim
68 words
A curl control system as claimed in claim 39, wherein said paper transport mechanism comprises a movable endless belt which is formed with a number of apertures, a suction tank interposed between an upper and a lower run of said endless belt and formed with a number of openings through a top wall of said tank, and a vacuum fan disposed in a lower portion of said tank.
Claim 42
Dependent Claim
50 words
A curl control system as claimed in claim 40, wherein said suction adjusting means comprises shutters each being associated with a respective one of the openings of said suction tank for selectively fully opening, fully closing and partly opening the opening on the basis of conditions of the curl sensed.
Claim 43
Dependent Claim
61 words
A curl control system as claimed in claim 41, wherein said suction adjusting means further comprises allowable curl setting means for setting an allowable curl level, excess curl detector means for reporting an excess curl when the curl sensed is above the allowable curl level, and control means for driving said shutters in response to a signal indicative of any curl.
Claim 44
Dependent Claim
75 words
A curl control system as claimed in claim 40, wherein said suction adjusting means comprises ducts each providing communication between said vacuum fan and a respective one of compartments which are defined in said suction tank and are each associated with a respective one of said openings, and shutters each being associated with a respective one of said ducts for selectively opening and closing said duct on the basis of conditions of the curl sensed.
Claim 45
Dependent Claim
62 words
A curl control system as claimed in claim 43, wherein said suction adjusting means further comprises allowable curl level setting means for setting an allowable curl level, excess curl detector means for reporting an excess curl when the curl sensed is above the allowable curl level, and control means for driving said shutters in response to a signal indicative of any curl.
Claim 46
Dependent Claim
79 words
A curl control system as claimed in claim 1, wherein said curl correcting means comprises: guide means for, on the basis of a signal indicative of the conditions of the curl sensed, guiding the paper to a nipping section of a thermal fixing roller pair which is provided at a fixing station of the image forming apparatus, and guide means positioning means for, on the basis of conditions of the curl sensed, adjusting a position of said guide means.
Claim 47
Dependent Claim
33 words
A curl control system as claimed in claim 45, wherein said guide means comprises a guide plate having a guide surface which is movable in a direction of transport toward the nipping section.
Claim 48
Dependent Claim
40 words
A curl control system as claimed in claim 46, wherein an angle between said guide surface of said guide plate and the direction of transfer toward the nipping section is variable on the basis of conditions of the curl sensed.
Claim 49
Dependent Claim
37 words
A curl control system as claimed in claim 46, wherein a distance between said guide plate and a fixing roller of the thermal fixing roller pair is variable on the basis of conditions of the curl sensed.
Claim 50
Dependent Claim
28 words
A curl control system as claimed in claim 46, wherein said guide plate is made up of a plurality of segments each being movable independently of the others.
Claim 51
Dependent Claim
49 words
A curl control system as claimed in claim 1, wherein said curl correcting means comprises: a pawl disposed downstream, of a nipping section of a thermal fixing roller pair and pawl positioning means for adjusting a position of said pawl on the basis of conditions of the curl sensed.
Claim 52
Dependent Claim
28 words
A curl control system as claimed in claim 50, wherein said pawl positioning means changes a contact position of said pawl with the periphery of the fixing roller.
Claim 53
Dependent Claim
29 words
A curl control system as claimed in claim 51, wherein said pawl positioning means comprises drive means for displacing said pawl and control means for controlling said drive means.
Claim 54
Dependent Claim
27 words
A curl control system as claimed in claim 52, wherein said control means activates said drive means when the curl sensed is above the allowable curl level.
Claim 55
Dependent Claim
36 words
A curl control system as claimed in claim 1, wherein said curl correcting means comprises feed control means for feeding a stack of papers one by one from a paper feeder of the image forming apparatus.
Claim 56
Dependent Claim
23 words
A curl control system as claimed in claim 54, wherein said paper feeder comprises a two-side tray provided for a two-side copy mode.
Claim 57
Dependent Claim
78 words
A curl control system as claimed in claim 55, wherein said feed control means comprises suction means disposed in a lower portion of the two-side tray for sucking the lowermost paper of the stack, air knife means for blowing air to between the papers of the stack, and control means for changing a suction exerted by said suction means an amount of air blown by said air knife means on the basis of conditions of the curl sensed.
Claim 58
Dependent Claim
26 words
A curl control system as claimed in claim 56, wherein said air knife means comprises a first humidifier for humdifying the stack of papers from below.
Claim 59
Dependent Claim
27 words
A curl control system as claimed in claim 57, wherein said feed control means further comprises a second humidifier for humidifying the stack of papers from above.
Claim 60
Dependent Claim
32 words
A curl control system as claimed in claim 58, wherein said control means controls operations of said first humidifier and said second humidifier on the basis of conditions of the curl sensed.
Claim 61
Dependent Claim
26 words
A curl control system as claimed in claim 1, wherein said curl sensing means is located downstream of a fixing means of the image forming apparatus.
Claim 62
Dependent Claim
45 words
A curl control system as claimed in claim 1, further comprising paper transport control means for controlling transport of said paper along a paper transport path provided in the image forming apparatus under the sensed condition of any curl, without any correction of the curl.
Claim 63
Dependent Claim
79 words
A curl system, for controlling curl of a paper which is applicable to an image forming apparatus, comprising: curl sensing means located downstream of a fixing means of the image forming apparatus for sensing an amount and a direction of curl of the paper; and paper transport control means for controlling transport of said paper along a paper transport path provided in the image forming apparatus under the sensed condition by any curl, without any correction of the curl.
Claim 64
Dependent Claim
79 words
A curl system, for controlling curl of a paper which is applicable to an image forming apparatus, comprising: curl sensing means located downstream of a fixing means of the image forming apparatus for sensing an amount and a direction of curl of the paper; and paper transport control means for controlling transport of said paper along a paper transport path provided in the image forming apparatus under the sensed condition by any curl, without any correction of the curl.
References Cited (Backward Citations)
US4068946A
Cited
JPS5335731A
Cited
US4763164A
Cited
US4453820A
Cited
US4417800A
Cited
US4596632A
Cited
US4763889A
Cited
US4623975A
Cited
US4540275A
Cited
JPS5930156A
Cited
US4542977A
Cited
US4641272A
Cited
US4505695A
Cited
US4627718A
Cited
US4673279A
Cited
JPS6050568A
Cited
US4539072A
Cited
US4652110A
Cited
US4666289A
Cited
JPS6128754A
Cited
US4632533A
Cited
US4591259A
Cited
US4727385A
Cited
US4734721A
Cited
US4708468A
Cited
US4733310A
Cited
US4771318A
Cited
JPS6365647A
Cited
US4804998A
Cited
US4747911A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-05-14 | 1993-11-13 | 1994-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-14 | 1997-11-13 | 1998-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-14 | 2001-11-13 | 2002-05-15 | $7700.00 | Window Closed / Lapsed |