JPH0535146A - Fixing device for image forming device - Google Patents
Fixing device for image forming deviceInfo
- Publication number
- JPH0535146A JPH0535146A JP3187509A JP18750991A JPH0535146A JP H0535146 A JPH0535146 A JP H0535146A JP 3187509 A JP3187509 A JP 3187509A JP 18750991 A JP18750991 A JP 18750991A JP H0535146 A JPH0535146 A JP H0535146A
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- fixing
- abnormality
- fixing roller
- turned
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000005856 abnormality Effects 0.000 claims abstract description 50
- 238000001514 detection method Methods 0.000 claims abstract description 13
- 230000002159 abnormal effect Effects 0.000 claims description 15
- 230000007257 malfunction Effects 0.000 abstract description 3
- 238000010438 heat treatment Methods 0.000 abstract description 2
- 230000002401 inhibitory effect Effects 0.000 abstract description 2
- 230000000630 rising effect Effects 0.000 abstract description 2
- 230000007547 defect Effects 0.000 description 4
- 230000002950 deficient Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 1
Landscapes
- Fixing For Electrophotography (AREA)
- Control Or Security For Electrophotography (AREA)
- Control Of Temperature (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、プリンタ、複写機、フ
ァクシミリ等の画像形成装置の定着装置に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for an image forming apparatus such as a printer, a copying machine and a facsimile.
【０００２】[0002]
【従来の技術】図４に例示されるように、画像形成装置
の定着装置としては、熱源である定着ヒータ５ａを内蔵
する定着ローラ５と、これに圧接する加圧ローラ１３と
を有する熱ローラ定着装置が公知であり、当該両ローラ
の間に、未定着のトナー像を担持した転写紙１４を通紙
し、トナー像を転写紙面に融着するようになっている。2. Description of the Related Art As shown in FIG. 4, as a fixing device of an image forming apparatus, a heat roller having a fixing roller 5 having a fixing heater 5a as a heat source and a pressure roller 13 in pressure contact with the fixing roller 5a. A fixing device is known, and a transfer paper 14 carrying an unfixed toner image is passed between the rollers to fuse the toner image to the transfer paper surface.
【０００３】当該様式の定着装置では、一般的に、定着
ローラ５表面に一定の圧力で接触するように取り付けら
れたサーミスタたる温度センサ７によって、定着ローラ
５表面の実際の温度が検出され、温度検出回路８を介し
てマイクロコンピュータ１に入力され、予め設定された
定着ローラ５の表面温度の制御目標値と比較される。そ
して当該制御目標値の下限値より低い場合には、スイッ
チング回路６が作動し、定着ヒータ５ａをオンにし、温
度センサ７で検知される定着ローラ５の表面温度が制御
目標値の上限値を超えると、定着ヒータ５ａをオフす
る。こうすることによって、定着ローラ５の表面温度を
所定の温度範囲に維持する。In a fixing device of this type, a temperature sensor 7, which is a thermistor mounted so as to come into contact with the surface of the fixing roller 5 at a constant pressure, generally detects the actual temperature of the surface of the fixing roller 5 and detects the temperature. It is input to the microcomputer 1 through the detection circuit 8 and compared with a preset control target value of the surface temperature of the fixing roller 5. When the control target value is lower than the lower limit value, the switching circuit 6 is activated to turn on the fixing heater 5a, and the surface temperature of the fixing roller 5 detected by the temperature sensor 7 exceeds the upper limit value of the control target value. Then, the fixing heater 5a is turned off. By doing so, the surface temperature of the fixing roller 5 is maintained within a predetermined temperature range.
【０００４】[0004]
【発明が解決しようとする課題】ところが、例えば、サ
ーミスタの加圧力が少なかったり、定着ローラ表面から
離れていたり等、サーミスタの取付不良があると、サー
ミスタにより検出される温度が所定温度になった時に
は、定着ローラ表面の実際の温度は、検出温度よりも高
い場合がある。その結果、転写紙が必要以上に加熱され
てカールしたり、最悪の場合には、定着部から発煙し、
機械を壊してしまう可能性すらある。However, if the thermistor is improperly mounted, for example, when the pressure applied to the thermistor is small or it is far from the surface of the fixing roller, the temperature detected by the thermistor reaches a predetermined temperature. At times, the actual temperature of the fuser roller surface may be higher than the detected temperature. As a result, the transfer paper is heated more than necessary and curls, or, in the worst case, smokes from the fixing unit.
There is even the possibility of breaking the machine.
【０００５】また、サーミスタ素子自身の不良、熱源で
ある定着ヒータ自身の不良や接触不良によっても同様の
異常が発生する可能性があり、接触不良等により定着ロ
ーラの表面温度が所定の温度まで上がらず、定着が出来
ないという異常が発生する可能性もある。また、使用環
境温度、使用電源電圧値が動作保証されている範囲より
低い時、ウォーム・アップタイムが遅いとか定着不良を
引き起こす可能性があるというような不具合も起こりう
る。A similar abnormality may occur due to a defect of the thermistor element itself, a defect of the fixing heater itself as a heat source, or a contact failure. Due to contact failure or the like, the surface temperature of the fixing roller rises to a predetermined temperature. However, there is a possibility that an abnormality will occur that fixing cannot be performed. Further, when the operating environment temperature and the operating power supply voltage value are lower than the guaranteed operation range, there is a possibility that the warm-up time is slow or there is a possibility that fixing failure may occur.
【０００６】そこで本発明の課題は、従来の熱ローラ定
着のヒータ制御の上記問題に対して、サーミスタたる温
度センサの不良あるいは温度センサの取付不良に起因す
る誤検知、又は定着ヒータ自身の不良、定着ヒータの接
触不良による定着異常、又は使用環境温度、使用電源電
圧が動作保証内にあるか否かを、安価で且つ短時間に防
止する制御機構を有した定着装置を提供するにある。Therefore, an object of the present invention is to solve the above-mentioned problem of the conventional heater control for heat roller fixing, erroneous detection due to a defect of the temperature sensor which is a thermistor or a defective mounting of the temperature sensor, or a defect of the fixing heater itself, It is an object of the present invention to provide a fixing device having a control mechanism that prevents, in a short time, an abnormal fixing due to poor contact of a fixing heater, or whether or not the operating environment temperature and the operating power supply voltage are within the guaranteed operation.
【０００７】[0007]
【課題を解決するための手段】本発明は、上記の課題
を、熱源を備えた定着ローラと、加圧ローラと、定着ロ
ーラの表面温度を検出するサーミスタたる温度センサ
と、当該温度センサの検出信号に従って熱源である定着
ヒータをオン、オフ制御して定着ローラの表面温度を所
定温度範囲に維持する制御手段とを有し、未定着トナー
像を担持する転写紙を接触搬送し、加熱することにより
定着を行なう画像形成装置の定着装置において、定着ヒ
ータの異常、又は温度センサの異常、又は使用電源電
圧、使用環境温度が動作保証内にあるか否かを検出する
異常検出手段と、当該検出手段で異常が検出された際に
定着ヒータの駆動を禁止する手段とを備えることにより
解決した。SUMMARY OF THE INVENTION The present invention solves the above problems by a fixing roller provided with a heat source, a pressure roller, a temperature sensor which is a thermistor for detecting the surface temperature of the fixing roller, and detection by the temperature sensor. Control means for controlling on / off of a fixing heater which is a heat source according to a signal to maintain the surface temperature of the fixing roller within a predetermined temperature range, and contact-transporting and heating a transfer sheet carrying an unfixed toner image. In a fixing device of an image forming apparatus that performs fixing by means of abnormality detection means for detecting whether the fixing heater is abnormal, or the temperature sensor is abnormal, or whether the operating power supply voltage or operating environment temperature is within the operation guarantee, and the detection. The problem is solved by including means for prohibiting driving of the fixing heater when an abnormality is detected by the means.
【０００８】電源を所定時間以上オフした後に再投入
し、温度センサによる検知温度が動作保証範囲内にある
場合に、定着ローラの表面温度が所定温度に達した後
に、所定時間定着ローラを連続回転又は断続回転させ
て、定着ローラ回転時と定着ローラ無回転時とでの温度
センサによる温度勾配を比較して、両者の温度勾配の差
が一定以上である時に、異常検出手段が異常と判断・検
出すれば、好適である。When the power source is turned off again for a predetermined time or longer and the temperature detected by the temperature sensor is within the operation guarantee range, the fixing roller is continuously rotated for a predetermined time after the surface temperature of the fixing roller reaches the predetermined temperature. Or, by intermittently rotating and comparing the temperature gradients by the temperature sensor between when the fixing roller is rotating and when the fixing roller is not rotating, and when the difference between the temperature gradients of the two is more than a certain value, the abnormality detecting means determines that there is an abnormality. If detected, it is preferable.
【０００９】電源投入直後、温度センサによる検出温度
が、所定温度以下の値を一定時間示した場合に、異常検
出手段が異常と判断・検出することも、好適である。It is also preferable that the abnormality detecting means determines and detects an abnormality when the temperature detected by the temperature sensor shows a value equal to or lower than a predetermined temperature for a certain period of time immediately after the power is turned on.
【００１０】同様に、電源を投入し所定の時間経過した
後、検出温度が、所定温度以下の値を一定時間示した場
合や、電源投入後、検出温度が、一定時間変化しない場
合や、電源投入後、検出温度が、所定温度を一定時間超
えた場合に、異常検出手段が異常と判断・検出すること
も、好適である。Similarly, when the detected temperature shows a value equal to or lower than the predetermined temperature for a certain time after the power is turned on for a predetermined time, or when the detected temperature does not change after the power is turned on for a certain time, It is also preferable that the abnormality detecting means determines and detects an abnormality when the detected temperature exceeds a predetermined temperature for a certain period of time after the charging.
【００１１】[0011]
【実施例】本発明の詳細を、図１に示された異常判断に
関するフローチャートに沿って説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described with reference to the flowchart for abnormality determination shown in FIG.
【００１２】先ず、中央演算処理ユニット（以下、「Ｃ
ＰＵ」という）の内部タイマの測定により、電源が所定
時間以上オフされてから再接続されたか否かが判断され
る。再接続されたのが、所定時間以上オフされていた後
である場合には、温度センサにより定着ローラの表面温
度をｔ0として検出し、動作保証内にあるか否か判断す
る。所定時間経過していない場合には、ｔ2として検出
する。First, a central processing unit (hereinafter referred to as "C
(Hereinafter referred to as "PU"), it is determined whether or not the power supply is turned off for a predetermined time or longer and then reconnected. If the reconnection is after being turned off for a predetermined time or longer, the temperature sensor detects the surface temperature of the fixing roller as t 0 , and determines whether the operation is within the guaranteed operation. When the predetermined time has not elapsed, it is detected as t 2 .
【００１３】所定時間以上オフされていた場合、図２に
示されたように、或る一定時間ｔ秒間に対する定着ヒー
タの温度上昇Ｄを、温度センサにより測定しＣＰＵで算
出する。When it has been turned off for a predetermined time or longer, as shown in FIG. 2, the temperature rise D of the fixing heater for a certain fixed time t seconds is measured by the temperature sensor and calculated by the CPU.
【００１４】電源投入後、所定時間ｓの経過を、ＣＰＵ
の内部タイマにより測定し、所定時間ｓが経過したなら
ば、温度センサにより定着ローラの表面温度をｔ1とし
て検出する。所定時間経過していないものについては、
最初のステップと同様にｔ2として検出する。After the power is turned on, the CPU waits for a predetermined time s.
When a predetermined time s has elapsed, the temperature sensor detects the surface temperature of the fixing roller as t 1 . For those that have not passed the predetermined time,
Similar to the first step, it is detected as t 2 .
【００１５】当該ｔ1が、所定温度Ｔ1に達しているか否
かを調べ、所定温度Ｔ1に達していない場合には異常と
判断する。異常の原因としては、定着ヒータが断線して
いるとか、温度センサが定着ローラから離れている等が
考えられる。異常と判断されると、禁止手段により、定
着ヒータの駆動が停止される。異常を表示する表示手段
を設けるようにして、これによってオペレータに速やか
に知らせて、不良サーミスタ素子の取替え等、異常処理
が行なわれる。当該異常が解消され解除手段によって定
着ヒータの駆動停止を解除するまで、保持手段が異常で
あることを記憶保持し、機械の誤作動を阻止するように
構成することができる。上記禁止手段は、定着ヒータの
駆動を停止させるが、電源自体を遮断するようにしても
よい。Whether t 1 has reached the predetermined temperature T 1 is checked, and if it has not reached the predetermined temperature T 1 , it is determined to be abnormal. The cause of the abnormality may be that the fixing heater is broken or the temperature sensor is separated from the fixing roller. If it is determined to be abnormal, the prohibiting unit stops driving the fixing heater. A display means for displaying an abnormality is provided so that the operator can be informed promptly and abnormality processing such as replacement of a defective thermistor element is performed. It can be configured such that the holding unit stores and holds the abnormality and prevents the malfunction of the machine until the abnormality is eliminated and the driving stop of the fixing heater is released by the release unit. The prohibiting means stops the driving of the fixing heater, but may interrupt the power source itself.
【００１６】ｔ1が所定温度Ｔ1に達していた場合には、
定着ローラを連続回転又は断続回転させる。図２に示さ
れたように、或る一定時間ｔ秒間に対する定着ヒータの
温度上昇ｄを、温度センサにより測定しＣＰＵで算出す
る。ここで、温度センサが取付不良であると、定着ロー
ラを回転させた際に定着ローラから離れる等して、Ｄ−
ｄの値が大きくなる。例えば、環境温度摂氏２３度にお
いては、Ｄ−ｄの値が、６．９〜９．０（ｄｅｇ）の範
囲外であれば、異常と判断する。異常と判断されると、
禁止手段により、定着ヒータの駆動が停止され、異常処
理が行なわれる。表示手段によるオペレータへの通報、
保持手段による異常状態の記憶保持、解除手段による定
着ヒータの駆動の停止を上記と同様に構成することが好
適である。経験則に基づくＤ−ｄの適正値の例を表１に
示す。When t 1 has reached the predetermined temperature T 1 ,
The fixing roller is rotated continuously or intermittently. As shown in FIG. 2, the temperature rise d of the fixing heater for a certain fixed time t seconds is measured by the temperature sensor and calculated by the CPU. Here, if the temperature sensor is not properly attached, the temperature sensor is separated from the fixing roller when the fixing roller is rotated, and D-
The value of d becomes large. For example, when the environmental temperature is 23 degrees Celsius and the value of D-d is outside the range of 6.9 to 9.0 (deg), it is determined to be abnormal. When judged to be abnormal,
The prohibiting unit stops the driving of the fixing heater and performs an abnormal process. Report to the operator by display means,
It is preferable that the storage of the abnormal state by the holding unit and the stop of the driving of the fixing heater by the releasing unit are configured in the same manner as described above. Table 1 shows an example of an appropriate value of Dd based on an empirical rule.
【００１７】[0017]
【表１】 [Table 1]
【００１８】更に、温度センサで、定着ローラの表面温
度ｔ2を検出する。当該温度が、例えば、環境温度より
もかなり低い温度等、ありえないような温度Ｔ2と比較
して、これより低いときに、異常と判断する。異常と判
断されると、禁止手段により、定着ヒータの駆動が停止
され、異常処理がなされる。異常の原因としては、定着
ヒータが断線している等が考えられる。一旦所定温度Ｔ
1を超えた場合でも、温度センサの取付不良等により温
度センサによる検知温度が下がることがありうるのは当
然である。表示手段によるオペレータへの通報、保持手
段による異常状態の記憶保持、解除手段による定着ヒー
タの駆動の停止を上記と同様に構成することが好適であ
る。Further, the temperature sensor detects the surface temperature t 2 of the fixing roller. When the temperature is lower than this temperature T 2 which is unlikely, for example, a temperature considerably lower than the ambient temperature, it is determined to be abnormal. When it is determined that there is an abnormality, the prohibiting unit stops driving the fixing heater and performs an abnormality process. The cause of the abnormality may be that the fixing heater is broken. Once the predetermined temperature T
Even if it exceeds 1 , it is natural that the temperature detected by the temperature sensor may decrease due to improper mounting of the temperature sensor. It is preferable that the display means notify the operator, the holding means holds and stores the abnormal state, and the releasing means stops the driving of the fixing heater in the same manner as described above.
【００１９】Ｔ2よりも高い場合には、更に温度センサ
により定着ローラの表面温度をｔ3として検出する。ｔ2
＝ｔ3、すなわち、ある一定時間温度センサの値が変化
しない場合には、異常と判断する。異常と判断される
と、禁止手段により、定着ヒータの駆動が停止され、異
常処理がなされる。異常の原因としては、温度センサが
定着ローラから離れている等が考えられる。If it is higher than T 2 , the surface temperature of the fixing roller is further detected as t 3 by the temperature sensor. t 2
= T 3 , that is, when the value of the temperature sensor does not change for a certain period of time, it is determined to be abnormal. When it is determined that there is an abnormality, the prohibiting unit stops driving the fixing heater and performs an abnormality process. The cause of the abnormality may be that the temperature sensor is away from the fixing roller.
【００２０】ｔ3が、所定の危険温度Ｔ3を超えた場合に
も、異常と判断する。異常と判断されると、禁止手段に
より、定着ヒータの駆動が停止され、異常処理がなされ
る。Even when t 3 exceeds a predetermined dangerous temperature T 3 , it is determined to be abnormal. When it is determined that there is an abnormality, the prohibiting unit stops driving the fixing heater and performs an abnormality process.
【００２１】所定の危険温度Ｔ3を超えていない場合に
は、再び定着ローラの無回転時の温度上昇Ｄが温度セン
サにより測定されＣＰＵで算出され、上記ステップが繰
り返される。When the predetermined dangerous temperature T 3 is not exceeded, the temperature rise D of the fixing roller in the non-rotation state is measured again by the temperature sensor, calculated by the CPU, and the above steps are repeated.
【００２２】定着ローラの表面温度が所定温度範囲に達
して、温度センサの検出信号に従って制御手段で定着ヒ
ータをオン、オフ制御して定着ローラの表面温度を当該
所定温度範囲に維持する段階においても、上記ステップ
を繰り返して、温度センサの取付不良等の異常を検知す
ることができる。Even when the surface temperature of the fixing roller reaches the predetermined temperature range, and the fixing heater is turned on / off by the control means in accordance with the detection signal of the temperature sensor to maintain the surface temperature of the fixing roller within the predetermined temperature range. The above steps can be repeated to detect an abnormality such as a defective mounting of the temperature sensor.
【００２３】結局、本発明においては、とりわけ次のい
ずれかに該当する場合に異常と判断して定着ヒータの駆
動を停止し、定着ヒータの接触不良等に起因する定着異
常等を回避する。After all, in the present invention, the driving of the fixing heater is stopped when it is judged to be abnormal, particularly in any of the following cases, and the fixing abnormality caused by the contact failure of the fixing heater or the like is avoided.
【００２４】（１）電源を所定時間以上オフした後に再
投入し、温度センサによる検知温度が動作保証範囲内に
ある場合に、定着ローラの表面温度が所定温度に達した
後に、所定時間定着ローラを連続回転又は断続回転させ
て、定着ローラ回転時と定着ローラ無回転時とでの温度
センサによる温度勾配を比較して、両者の温度勾配の差
が一定以上である場合。(1) The power is turned off and on again for a predetermined time, and when the temperature detected by the temperature sensor is within the operation guarantee range, after the surface temperature of the fixing roller reaches a predetermined temperature, the fixing roller is kept for a predetermined time. When the fixing roller is rotated continuously or intermittently, and the temperature gradients by the temperature sensor are compared when the fixing roller is rotating and when the fixing roller is not rotating, and the difference between the temperature gradients is equal to or more than a certain value.
【００２５】（２）電源投入直後、温度センサによる検
出温度が、所定温度以下の値を一定時間示した場合。一
定時間継続することを問題にするのは、ノイズ対策であ
る。(2) When the temperature detected by the temperature sensor shows a value below a predetermined temperature for a certain period of time immediately after the power is turned on. It is a noise countermeasure that makes it a problem to continue for a certain period of time.
【００２６】（３）電源を投入し所定の時間経過した
後、検出温度が、所定温度以下の値を一定時間（ノイズ
対策）示した場合。(3) When the detected temperature shows a value equal to or lower than the predetermined temperature for a predetermined time (countermeasures against noise) after the power is turned on and a predetermined time has elapsed.
【００２７】（４）電源投入後、検出温度が、一定時間
（ノイズ対策）変化しない場合。(4) When the detected temperature does not change for a certain period of time (countermeasures against noise) after the power is turned on.
【００２８】（５）電源投入後、検出温度が、所定温度
を一定時間（ノイズ対策）超えた場合。(5) When the detected temperature exceeds a predetermined temperature for a certain time (noise countermeasure) after the power is turned on.
【００２９】また本発明における電気回路の概略を図３
に例示する。上記ＣＰＵ等からなり、定着ヒータ５６を
オン、オフ制御する制御手段を兼ねる制御部５１は、複
写機全体の制御を行なう。制御部５１は、定着装置の定
着ヒータ５６を駆動するヒータ駆動部５２、定着ヒータ
５６により加熱される定着ローラ５７表面の温度を検知
する温度センサ５３、ＲＯＭ５４及びＲＡＭ５５などと
接続されている。FIG. 3 is a schematic diagram of an electric circuit according to the present invention.
For example. The control unit 51 including the above-mentioned CPU and the like, which also serves as control means for controlling on / off of the fixing heater 56, controls the entire copying machine. The control unit 51 is connected to a heater driving unit 52 that drives the fixing heater 56 of the fixing device, a temperature sensor 53 that detects the temperature of the surface of the fixing roller 57 heated by the fixing heater 56, a ROM 54, a RAM 55, and the like.
【００３０】制御部５１は、定着ローラ５７の表面に接
して設けられる温度センサ５３からのデータ（電圧値）
により、定着ヒータコントロール用のプログラムに従っ
てヒータ駆動部５２にオン／オフ信号を送り、定着ロー
ラ５７の表面温度を制御する。The control section 51 receives data (voltage value) from the temperature sensor 53 provided in contact with the surface of the fixing roller 57.
Thus, an ON / OFF signal is sent to the heater driving unit 52 in accordance with a fixing heater control program to control the surface temperature of the fixing roller 57.
【００３１】ＲＯＭ５４には、制御プログラムなどが記
憶され、ＲＡＭ５５には、定着ローラ５７の表面温度異
常、温度センサ５３異常、使用環境異常、電源電圧異常
などを規定する条件などが記憶されている。The ROM 54 stores control programs and the like, and the RAM 55 stores conditions such as surface temperature abnormality of the fixing roller 57, temperature sensor 53 abnormality, use environment abnormality, and power supply voltage abnormality.
【００３２】制御部５１は、温度センサ５３による検知
温度が、上記条件の範囲外である場合に、ヒータ駆動部
５２にオフ信号を強制的に送り、定着ヒータ５６をオフ
する。When the temperature detected by the temperature sensor 53 is out of the range of the above conditions, the controller 51 forcibly sends an OFF signal to the heater driver 52 to turn off the fixing heater 56.
【００３３】[0033]
【発明の効果】請求項１の定着装置においては、定着ヒ
ータの異常又は温度センサの異常を検出する異常検出手
段と、当該検出手段で異常が検出された際に定着ヒータ
の駆動を禁止する手段とが設けられているので、定着ロ
ーラ表面の温度検出用温度センサの不良あるいは温度セ
ンサの取付不良に起因する誤動作、例えば、規定以上に
定着ローラ表面の温度が上昇することが防がれ、転写紙
のカール、ジャムの発生が防止され、装置破損の防止に
効果が得られる。また定着ヒータの不良、接触不良によ
り温度が所定温度に達しないために起こる定着不良の防
止にも効果が得られる。更には、使用環境温度、使用電
源電圧値が、動作保証されている範囲にあるか否かも分
かる。According to the fixing device of the present invention, an abnormality detecting means for detecting an abnormality of the fixing heater or an abnormality of the temperature sensor, and a means for inhibiting the driving of the fixing heater when the abnormality is detected by the detecting means. Is provided, it is possible to prevent a malfunction due to a defective temperature sensor for temperature detection on the surface of the fixing roller or an improper mounting of the temperature sensor, for example, to prevent the temperature of the surface of the fixing roller from rising higher than a specified value. Curling and jamming of paper are prevented, which is effective in preventing damage to the device. Further, it is possible to prevent the fixing failure caused by the temperature not reaching the predetermined temperature due to the failure of the fixing heater or the contact failure. Furthermore, it is possible to know whether the operating environment temperature and the operating power supply voltage value are within the guaranteed operation range.
【００３４】請求項２の定着装置、請求項３の定着装置
及び請求項４の定着装置においては、電源を所定時間以
上オフした後に再投入し、温度センサによる検知温度が
動作保証範囲内にある場合に、定着ローラの表面温度が
所定温度に達した後に、所定時間定着ローラを連続回転
又は断続回転させて、定着ローラ回転時と定着ローラ無
回転時とでの温度センサによる温度勾配を比較して、両
者の温度勾配の差が一定以上である時などに、異常検出
手段が異常と判断・検出するので、的確に温度センサの
取付不良等が分かり、必要な場合には機械の作動を停止
することができる。In the fixing device of the second aspect, the fixing device of the third aspect and the fixing device of the fourth aspect, the power is turned off for a predetermined time or more and then turned on again, and the temperature detected by the temperature sensor is within the operation guarantee range. In this case, after the surface temperature of the fixing roller reaches a predetermined temperature, the fixing roller is continuously rotated or intermittently rotated for a predetermined time, and the temperature gradients by the temperature sensor are compared when the fixing roller is rotating and when the fixing roller is not rotating. When the difference in temperature gradient between the two is more than a certain value, the abnormality detection means determines and detects that there is an abnormality, so it is possible to accurately detect the temperature sensor mounting failure and stop the machine operation if necessary. can do.
【図１】本発明にかかる異常判断に関するフローチャー
トである。FIG. 1 is a flowchart regarding abnormality determination according to the present invention.
【図２】制御手段で定着ヒータをオン、オフ制御する前
までの定着ローラの表面温度と時間との関係を示すグラ
フである。FIG. 2 is a graph showing the relationship between the surface temperature of the fixing roller and the time until the fixing heater is turned on and off by the control means.
【図３】本発明の一例にかかる電気回路の概略図であ
る。FIG. 3 is a schematic diagram of an electric circuit according to an example of the present invention.
【図４】公知の定着装置の概略図である。FIG. 4 is a schematic view of a known fixing device.
５、５７ 定着ローラ ５ａ、５６ 定着ヒータ ７、５３ 温度センサ 5,57 fixing roller 5a, 56 fixing heater 7,53 Temperature sensor
Claims (4)
と、定着ローラの表面温度を検出する温度センサと、当
該温度センサの検出信号に従って熱源をオン、オフ制御
して定着ローラの表面温度を所定温度範囲に維持する制
御手段とを有し、未定着トナー像を担持する転写紙を接
触搬送し、加熱することにより定着を行なう画像形成装
置の定着装置において、定着ヒータの異常、又は温度セ
ンサの異常、又は、使用環境温度、使用電源電圧が動作
保証内にあるか否かを検出する異常検出手段と、当該検
出手段で異常が検出された際に定着ヒータの駆動を禁止
する手段とを備えたことを特徴とする定着装置。1. A fixing roller provided with a heat source, a pressure roller, a temperature sensor for detecting the surface temperature of the fixing roller, and a surface temperature of the fixing roller by controlling ON / OFF of the heat source according to a detection signal of the temperature sensor. In a fixing device of an image forming apparatus, which has a control means for maintaining a temperature within a predetermined temperature range, the transfer paper carrying an unfixed toner image is contact-conveyed and heated to perform fixing, an abnormality of a fixing heater or a temperature An abnormality detection unit that detects whether the sensor is abnormal, or whether the operating environment temperature or the operating power supply voltage is within the operation guarantee, and a unit that prohibits driving of the fixing heater when the detecting unit detects an abnormality. A fixing device comprising:
した場合に、定着ローラの表面温度が所定温度に達した
後に、所定時間定着ローラを連続回転又は断続回転させ
て、定着ローラ回転時と定着ローラ無回転時とでの温度
センサによる温度勾配を比較して、両者の温度勾配の差
が一定以上である時に、上記異常検出手段が異常と判断
・検出することを特徴とする請求項１に記載の定着装
置。2. When the power is turned off again for a predetermined time or longer and then turned on again, after the surface temperature of the fixing roller reaches a predetermined temperature, the fixing roller is continuously rotated or intermittently rotated for a predetermined time to prevent the fixing roller from rotating. 2. The temperature gradient obtained by the temperature sensor when the fixing roller is not rotating is compared, and when the difference between the temperature gradients of the two is equal to or more than a certain value, the abnormality detecting means determines and detects an abnormality. The fixing device described in 1.
度が、所定温度以下の値を一定時間示した場合に、上記
異常検出手段が異常と判断・検出することを特徴とする
請求項１に記載の定着装置。3. Immediately after the power is turned on, when the temperature detected by the temperature sensor indicates a value below a predetermined temperature for a certain period of time, the abnormality detecting means determines and detects an abnormality. Fixing device.
出温度が、所定温度以下の値を一定時間示した場合、電
源投入後、検出温度が、一定時間変化しない場合、電源
投入後、検出温度が、所定温度を一定時間超えた場合の
いずれかに相当した場合に、上記異常検出手段が異常と
判断・検出することを特徴とする請求項１に記載の定着
装置。4. When a detected temperature shows a value equal to or lower than a predetermined temperature for a certain time after the power is turned on for a predetermined time, when the detected temperature does not change after the power is turned on for a certain time, after the power is turned on, 2. The fixing device according to claim 1, wherein the abnormality detecting unit determines and detects an abnormality when the detected temperature corresponds to any one of a case where the detected temperature exceeds a predetermined temperature for a certain period of time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3187509A JPH0535146A (en) | 1991-07-26 | 1991-07-26 | Fixing device for image forming device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3187509A JPH0535146A (en) | 1991-07-26 | 1991-07-26 | Fixing device for image forming device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0535146A true JPH0535146A (en) | 1993-02-12 |
Family
ID=16207313
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3187509A Pending JPH0535146A (en) | 1991-07-26 | 1991-07-26 | Fixing device for image forming device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0535146A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8064785B2 (en) | 2008-02-27 | 2011-11-22 | Sharp Kabushiki Kaisha | Fixing device, image forming apparatus, and method of detecting an abnormality of a fixing device |
-
1991
- 1991-07-26 JP JP3187509A patent/JPH0535146A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8064785B2 (en) | 2008-02-27 | 2011-11-22 | Sharp Kabushiki Kaisha | Fixing device, image forming apparatus, and method of detecting an abnormality of a fixing device |
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