US4740671A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature control apparatus for detecting an abnormality in a heater in a copying machine or the like
Assignee: Canon Inc
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Filing: 1986-10-30
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Granted: 1988-04-26
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Expires: 2006-10-30
Abstract
Abstract A temperature control apparatus for controlling, e.g., a fixing heater of a copying machine has a fuse resistor connected to the fixing heater through a power relay, a thermistor for detecting the surface temperature of a fixing roller heated by the fixing heater, abnormality timers for counting the ON time of the fixing heater and having different preset counts corresponding to different modes of the copying machine, and a control circuit for disconnecting the fuse resistor when the output from the thermistor indicates overheating or the ON time of the heater exceeds the preset count of the timer. Overheating of the heater is prevented with high reliability.
Inventors
- 👤 Kouki Kuroda
- 👤 Toshiaki Yagasaki
- 👤 Tsuneki Inuzuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 06:33
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/20; G03G15/2003; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/24
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
147 words
A temperature control apparatus comprising: heater means; temperature detecting means for detecting a temperature of said heater means; control means for controlling power supply to said heater means in accordance with an output from said temperature detecting means so as to regulate the temperature of said heater means at a predetermined level; and abnormality detecting means for detecting an abnormality of said heater means by measuring an ON time of said heater means, said abnormality detecting means being provided independently of said control means and having first and second timer means for measuring the ON time of said heater means, wherein said abnormality detecting means detects an abnormality of said heater means by selecting said first timer means or said second timer means in accordance with a state of said apparatus so as to vary a time period for measuring the ON time of the heater means.
Claim 2
Dependent Claim
147 words
A temperature control apparatus comprising: heater means; temperature detecting means for detecting a temperature of said heater means; control means for controlling power supply to said heater means in accordance with an output from said temperature detecting means so as to regulate the temperature of said heater means at a predetermined level; and abnormality detecting means for detecting an abnormality of said heater means by measuring an ON time of said heater means, said abnormality detecting means being provided independently of said control means and having first and second timer means for measuring the ON time of said heater means, wherein said abnormality detecting means detects an abnormality of said heater means by selecting said first timer means or said second timer means in accordance with a state of said apparatus so as to vary a time period for measuring the ON time of the heater means.
Claim 3
Dependent Claim
28 words
An apparatus according to claim 1, further comprising means for disconnecting power supply to said heater means in accordance with a detection output from said abnormality detecting means.
Claim 4
Dependent Claim
48 words
An apparatus according to claim 1, further comprising abnormal temperature increase detecting means for detecting an abnormal temperature increase of said heater means in accordance with a detection output from said temperature detecting means, wherein said abnormal temperature increase detecting means is provided independently of said control means.
Claim 5
Dependent Claim
59 words
An apparatus according to claim 2, further comprising abnormal temperature increase detecting means for detecting an abnormal temperature increase of said heater means in accordance with a detection output from said temperature detecting means, wherein said disconnecting means disconnects the power supply to said heater means in accordance with a detection output from said abnormal temperature increase detecting means.
Claim 6
Dependent Claim
48 words
An apparatus according to claim 1, further comprising third timer means for measuring a predetermine time, wherein said abnormality detecting means uses said first timer means until the predetermined time passes after said apparatus is turned ON, and uses said second timer means after the predetermined time passes.
Claim 7
Dependent Claim
30 words
An apparatus according to claim 5, wherein said first timer means measures a first time period which is longer than a second time period measured by said second timer means.
Claim 8
Dependent Claim
164 words
A temperature control apparatus comprising: heater means; temperature detecting means for detecting a temperature of said heater means; control means for controlling power supply to said heater means in accordance with an output from said temperature detecting means so as to regulate a temperature of said heater means to a predetermined level; abnormality detecting means for detecting an abnormality of said heater means by measuring an ON time of said heater means, said abnormality detecting means measuring an ON time of said heater means regardless of a temperature of said heating means, and for determining an abnormality of said heater means when the ON time exceeds a predetermined period; and abnormality temperature increase detecting means for detecting an abnormal temperature increase of said heater means, regardless of the ON time of said heater means, in accordance with a detection output from said temperature detecting means; wherein said abnormality detecting means and said abnormal temperature increase detecting means are provided independently of said control means.
Claim 9
Dependent Claim
164 words
A temperature control apparatus comprising: heater means; temperature detecting means for detecting a temperature of said heater means; control means for controlling power supply to said heater means in accordance with an output from said temperature detecting means so as to regulate a temperature of said heater means to a predetermined level; abnormality detecting means for detecting an abnormality of said heater means by measuring an ON time of said heater means, said abnormality detecting means measuring an ON time of said heater means regardless of a temperature of said heating means, and for determining an abnormality of said heater means when the ON time exceeds a predetermined period; and abnormality temperature increase detecting means for detecting an abnormal temperature increase of said heater means, regardless of the ON time of said heater means, in accordance with a detection output from said temperature detecting means; wherein said abnormality detecting means and said abnormal temperature increase detecting means are provided independently of said control means.
Claim 10
Dependent Claim
36 words
An apparatus according to claim 7, further comprising disconnecting means for disconnecting power supply to said heater means in accordance with an output from one of said abnormality detecting means and abnormal temperature increase detecting means.
Claim 11
Dependent Claim
70 words
An apparatus according to claim 7, wherein said abnormality detecting means includes first and second timer means for measuring the ON time of said heater means and detects an abnormality of said heater means by selecting said first timer means or said second timer means in accordance with a state of said apparatus so as to vary a period of time for measuring the ON time of said heater means.
Claim 12
Dependent Claim
48 words
An apparatus according to claim 9, further comprising third timer means for measuring a predetermined time, wherein said abnormality detecting means uses said first timer means until the predetermined time passes after said apparatus is turned ON and uses said second timer means after the predetermined time passes.
Claim 13
Dependent Claim
128 words
A temperature control apparatus comprising: heater means; temperature detecting means for detecting a temperature of said heater means; a microcomputer for controlling power supply to said heater means in accordance with an output from said temperature detecting means so as to regulate a temperature of said heater means at a predetermined level; and abnormality detecting means for detecting an abnormality of said heater means by measuring an ON time of said heater means, said abnormality detecting means being provided independently of said microcomputer; wherein said abnormality detecting means includes means for measuring an ON time of said heater means, regardless of a temperature of said heater means, and determines an abnormality of said heater means when the ON time measured by said measuring means exceeds a predetermined period.
Claim 14
Dependent Claim
128 words
A temperature control apparatus comprising: heater means; temperature detecting means for detecting a temperature of said heater means; a microcomputer for controlling power supply to said heater means in accordance with an output from said temperature detecting means so as to regulate a temperature of said heater means at a predetermined level; and abnormality detecting means for detecting an abnormality of said heater means by measuring an ON time of said heater means, said abnormality detecting means being provided independently of said microcomputer; wherein said abnormality detecting means includes means for measuring an ON time of said heater means, regardless of a temperature of said heater means, and determines an abnormality of said heater means when the ON time measured by said measuring means exceeds a predetermined period.
Claim 15
Dependent Claim
28 words
An apparatus according to claim 11, further comprising means for disconnecting power supply to said heater means in accordance with a detection output from said abnormality detecting means.
Claim 16
Dependent Claim
55 words
An apparatus according to claim 11, further comprising abnormal temperature increase detecting means for detecting an abnormal temperature increase of said heater means, regardless of the ON time of said heater means, in accordance with a detection output from said temperature detecting means, said abnormal temperature increase detecting means being provided independently of said microcomputer.
Claim 17
Dependent Claim
73 words
An apparatus according to claim 11, wherein said timer means includes first and second timer circuits for measuring an ON time of said heater means, and said abnormality detecting means detects an abnormality of said heater means by selecting said first timer circuit of said second timer circuit in accordance with a state of said apparatus so as to vary a period of time for measuring the ON time of said heater means.
Claim 18
Dependent Claim
48 words
An apparatus according to claim 14, further comprising third timer means for measuring a predetermine time, wherein said abnormality detecting means uses said first timer means until the predetermined time passes after said apparatus is turned ON, and uses said second timer means after the predetermined time passes.
Claim 19
Dependent Claim
146 words
A temperature control apparatus measuring heater means; temperature detecting means for detecting a temperature of said heater means; control means for controlling power supply to said heater means in accordance with an output from said temperature detecting means so as to regulate a temperature of said heater means to a predetermined level; abnormality detecting means for detecting an abnormality of said heater means by comparing an ON time of said heater means; and abnormal temperature increase detecting means for detecting an abnormal temperature increase of said heater means in accordance with a detection output from said temperature detecting means; wherein said abnormality detecting means has timer means for measuring said ON time of said heater means and reset means for resetting said timer means, said reset means resetting said timer means after the lapse of a predetermined time period when said heater means is turned off.
Claim 20
Dependent Claim
146 words
A temperature control apparatus measuring heater means; temperature detecting means for detecting a temperature of said heater means; control means for controlling power supply to said heater means in accordance with an output from said temperature detecting means so as to regulate a temperature of said heater means to a predetermined level; abnormality detecting means for detecting an abnormality of said heater means by comparing an ON time of said heater means; and abnormal temperature increase detecting means for detecting an abnormal temperature increase of said heater means in accordance with a detection output from said temperature detecting means; wherein said abnormality detecting means has timer means for measuring said ON time of said heater means and reset means for resetting said timer means, said reset means resetting said timer means after the lapse of a predetermined time period when said heater means is turned off.
Claim 21
Dependent Claim
130 words
A temperature control apparatus comprising: heater means; temperature detecting means for detecting a temperature of said heater means; a microcomputer for controlling power supply to said heater means in accordance with an output from said temperature detecting means so as to regulate a temperature of said heater means at a predetermined level; and abnormality detecting means for detecting an abnormality of said heater means by measuring an ON time of said heater means, said abnormality detecting means being provided independently of said microcomputer; wherein said abnormality detecting means has timer means for measuring said ON time of said heater means and reset means for resetting said timer means, said reset means resetting said timer means after the lapse of a predetermined time period when said heater means is turned off.
Claim 22
Dependent Claim
130 words
A temperature control apparatus comprising: heater means; temperature detecting means for detecting a temperature of said heater means; a microcomputer for controlling power supply to said heater means in accordance with an output from said temperature detecting means so as to regulate a temperature of said heater means at a predetermined level; and abnormality detecting means for detecting an abnormality of said heater means by measuring an ON time of said heater means, said abnormality detecting means being provided independently of said microcomputer; wherein said abnormality detecting means has timer means for measuring said ON time of said heater means and reset means for resetting said timer means, said reset means resetting said timer means after the lapse of a predetermined time period when said heater means is turned off.
Claim 23
Dependent Claim
154 words
A temperature control apparatus comprising: heater means; temperature detecting means for detecting a temperature of said heater means; control means for controlling power supply to said heater means in accordance with an output from said temperature detecting means so as to regulate the temperature of said heater means at a predetermined level; and abnormality detecting means for detecting an abnormality of said heater means by measuring an ON time of said heater means, said abnormality detecting means being provided independently of said control means, said abnormality detecting means having a plurality of modes and measuring the ON time in accordance with each of the plurality of modes; wherein said abnormality detecting means has timer means for measuring said ON time of said heater means and reset means for resetting said timer means, said reset means resetting said timer means after the lapse of a predetermined time period when said heater means is turned off.
Claim 24
Dependent Claim
154 words
A temperature control apparatus comprising: heater means; temperature detecting means for detecting a temperature of said heater means; control means for controlling power supply to said heater means in accordance with an output from said temperature detecting means so as to regulate the temperature of said heater means at a predetermined level; and abnormality detecting means for detecting an abnormality of said heater means by measuring an ON time of said heater means, said abnormality detecting means being provided independently of said control means, said abnormality detecting means having a plurality of modes and measuring the ON time in accordance with each of the plurality of modes; wherein said abnormality detecting means has timer means for measuring said ON time of said heater means and reset means for resetting said timer means, said reset means resetting said timer means after the lapse of a predetermined time period when said heater means is turned off.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-26 | 1991-10-26 | 1992-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-26 | 1995-10-26 | 1996-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-26 | 1999-10-26 | 2000-04-26 | $7700.00 | Window Closed / Lapsed |