JP2727561B2 - Temperature control device protection device - Google Patents
Temperature control device protection deviceInfo
- Publication number
- JP2727561B2 JP2727561B2 JP63103227A JP10322788A JP2727561B2 JP 2727561 B2 JP2727561 B2 JP 2727561B2 JP 63103227 A JP63103227 A JP 63103227A JP 10322788 A JP10322788 A JP 10322788A JP 2727561 B2 JP2727561 B2 JP 2727561B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- safety device
- current
- heating element
- temperature control
- 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.)
- Expired - Fee Related
Links
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、たとえば、電子複写機の定着装置等の加熱
装置の温度制御装置に関し、特に、加熱装置の過熱を防
止する保護装置に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control device of a heating device such as a fixing device of an electronic copying machine, and more particularly, to a protection device for preventing overheating of a heating device.
たとえば、電子複写機の定着装置においては、加熱ヒ
ータを内蔵した加熱ロールと加圧ロールが設けられてお
り、この加熱ロールと加圧ロールの間に用紙を通し、加
熱，加圧することにより転写画像を定着している。この
ような熱定着装置の定着工程においては、加熱ロールの
表面温度は、温度制御装置により、190〜200℃程度に制
御される。For example, in a fixing device of an electronic copying machine, a heating roll and a pressure roll having a built-in heater are provided, and a paper is passed between the heating roll and the pressure roll, and the transferred image is heated and pressed. Has been established. In the fixing step of such a heat fixing device, the surface temperature of the heating roll is controlled to about 190 to 200 ° C. by a temperature control device.
第２図に示すように、この温度制御装置９は、加熱ロ
ール１の表面に設けた温度センサ6,温度制御回路が設け
られた電気回路基板7,ソリッドステートリレー８等から
構成されている。ソリッドステートリレー８は、加熱ロ
ール１の加熱ヒータ２及び交流電源３の電流通路に対し
て直列に接続されており、温度センサ６により検出され
た加熱ロール１の表面温度に応じて電気回路基板７によ
りソリッドステートリレー８のオンオフ制御して加熱ロ
ール１の温度制御を行っている。更に、安全装置４が設
けられ、温度制御装置９が故障したときに、加熱ロール
１が異常高温にならないようにしている。As shown in FIG. 2, the temperature control device 9 includes a temperature sensor 6 provided on the surface of the heating roll 1, an electric circuit board 7 provided with a temperature control circuit, a solid state relay 8, and the like. The solid state relay 8 is connected in series with the heater 2 of the heating roll 1 and the current path of the AC power supply 3, and according to the surface temperature of the heating roll 1 detected by the temperature sensor 6, an electric circuit board 7 is provided. The on / off control of the solid state relay 8 controls the temperature of the heating roll 1. Further, a safety device 4 is provided to prevent the heating roll 1 from becoming abnormally high when the temperature control device 9 fails.
この安全装置４は、第２図に示すように加熱ロール１
の近傍に設けられ、加熱ロール１からの輻射熱及び対流
熱によって作動するサーモスタットや温度ヒューズ等を
加熱ロール１の加熱ヒータ２の電流通路に直列に接続し
た構成となっている。そして、温度制御装置９が何等か
の原因で正常に動作しなくなり、加熱ロール１の温度が
異常に高くなろうとするときに、その輻射熱及び対流熱
の増加を検出して、加熱ヒータ２の電流通路を遮断し、
過熱を防止するようにしている。The safety device 4 includes a heating roll 1 as shown in FIG.
, And a thermostat, a temperature fuse, and the like, which are operated by radiant heat and convective heat from the heating roll 1, are connected in series to a current path of the heater 2 of the heating roll 1. Then, when the temperature control device 9 does not operate normally for some reason and the temperature of the heating roll 1 is going to become abnormally high, the increase of the radiant heat and the convective heat is detected, and the current of the heater 2 is detected. Block the passage,
I try to prevent overheating.
上記従来の安全装置４においては、サーモススタット
や温度ヒューズに、加熱ヒータ２に流れる大電流がその
まま流れる。この大電流のため、安全装置４等で発熱す
る。したがって、安全装置４等における発熱による温度
上昇分を考慮して安全装置４の作動温度を設定する必要
があり、実際の制御温度以上の温度に安全装置４の作動
温度を設定する必要があった。In the conventional safety device 4 described above, a large current flowing through the heater 2 flows through the thermostat or the thermal fuse as it is. Due to this large current, heat is generated in the safety device 4 or the like. Therefore, it is necessary to set the operating temperature of the safety device 4 in consideration of a temperature rise due to heat generation in the safety device 4 and the like, and it is necessary to set the operating temperature of the safety device 4 to a temperature equal to or higher than the actual control temperature. .
しかも、安全装置４や他の配線との接続部で発熱する
発熱量及びこれによる温度上昇は、電気抵抗値，電流
値，通電時間及び熱容量等の変化によって大きく影響さ
れ不安定である。このため、安全装置４の誤動作を引き
起こすおそれがあり、温度制御装置９に対する安全装置
としての機能を確実に果たすことができないという問題
があった。In addition, the amount of heat generated by the safety device 4 and the connection with the other wiring and the resulting temperature rise are greatly affected by changes in the electrical resistance value, current value, conduction time, heat capacity, and the like, and are unstable. For this reason, there is a possibility that a malfunction of the safety device 4 may be caused, and there is a problem that the function as a safety device for the temperature control device 9 cannot be reliably performed.
たとえば、本来加熱ロール１の温度がＴ℃になったと
きに安全装置４を作動させたい場合、設定温度をＴ℃に
したのでは安全装置４等での発熱による温度上昇分ΔＴ
のために、加熱ロール１の温度がＴ℃になる前にすなわ
ち、（Ｔ−ΔＴ）℃で安全装置４が作動してしまう。こ
のため、安全装置４等の温度上昇分ΔＴを考慮して安全
装置４の作動温度を高めの（Ｔ＋ΔＴ）℃に設定し、加
熱ロール１の温度がＴ℃になったときに安全装置４を作
動させるようにしている。ところが、この安全装置４等
による温度上昇分ΔＴは上述のように不安定であり、場
合によっては安全装置４等における温度上昇があまりな
いことがある。このような場合、加熱ロール１の温度が
（Ｔ＋ΔＴ）℃になるまで安全装置４が作動しないこと
になり、加熱ロール１の温度が上限を越え、加熱ヒータ
２自体が損傷するばかりでなく、他の部材に対しても損
傷を与えるという問題があった。For example, if the safety device 4 is to be operated when the temperature of the heating roll 1 becomes T ° C., the temperature rise ΔT due to the heat generated by the safety device 4 or the like may be obtained if the set temperature is set to T ° C.
Therefore, the safety device 4 is activated before the temperature of the heating roll 1 reaches T ° C., that is, at (T−ΔT) ° C. Therefore, the operating temperature of the safety device 4 is set to a higher (T + ΔT) ° C. in consideration of the temperature rise ΔT of the safety device 4 and the like, and the safety device 4 is turned off when the temperature of the heating roll 1 reaches T ° C. It works. However, the temperature rise ΔT caused by the safety device 4 or the like is unstable as described above, and in some cases, the temperature rise in the safety device 4 or the like is not so large. In such a case, the safety device 4 does not operate until the temperature of the heating roll 1 becomes (T + ΔT) ° C., and the temperature of the heating roll 1 exceeds the upper limit, and not only the heater 2 itself is damaged, but also other There is a problem that the member is also damaged.
本発明は、上述の問題点を解決するために案出された
ものであって、安全装置等における発熱を防止して、安
全装置の誤動作を防止することを目的とする。The present invention has been devised to solve the above-described problem, and has as its object to prevent heat generation in a safety device or the like and prevent malfunction of the safety device.
〔課題を解決するための手段〕 本発明の温度制御装置の保護装置は、前記目的を達成
するため、温度制御される発熱体の電流通路に、前記発
熱体の温度が設定温度以上となったときに、発熱体から
の熱を受けて開回路となる安全装置を直列に接続すると
共に、この安全回路に並列に分流回路を接続し、この分
流回路に、前記発熱体に流れる電流から前記安全装置に
流れる電流を差し引いた大きさの電流では開回路とはな
らないが、前記発熱体に流れる電流では開回路となる特
性を持たせたことを特徴とする。[Means for Solving the Problems] In the protection device for a temperature control device of the present invention, in order to achieve the above object, the temperature of the heating element is equal to or higher than a set temperature in a current path of the heating element to be temperature controlled. At the same time, a safety device that is opened by receiving heat from the heating element is connected in series, and a shunt circuit is connected in parallel to the safety circuit, and the shunt circuit is connected to the safety circuit from a current flowing through the heating element. A characteristic is that an open circuit is not formed with a current having a magnitude obtained by subtracting a current flowing through the device, but an open circuit is formed with a current flowing through the heating element.
また、前記分流回路としては、ヒューズを使用するこ
とができる。Further, a fuse can be used as the shunt circuit.
通常状態にあっては、発熱体に流れる電流は、安全装
置と分流回路に分かれて流れる。したがって、安全装置
に流れる電流は発熱体に流れる電流より小さなものとな
り、安全装置等における発熱量が減少する。これによ
り、安全装置における温度上昇は小さなものとなり、安
全装置が作動する温度を正確に設定することができる。In the normal state, the current flowing through the heating element flows through the safety device and the shunt circuit separately. Therefore, the current flowing through the safety device is smaller than the current flowing through the heating element, and the amount of heat generated in the safety device or the like decreases. As a result, the temperature rise in the safety device is small, and the temperature at which the safety device operates can be set accurately.
また、たとえば、温度制御装置が故障して発熱体の温
度が設定温度以上になろうとしたときには、安全装置が
作動して発熱体の電流通路は開回路になる。また、安全
装置の作動と連動して分流回路の電流通路も開回路とな
るので、発熱体に流れる電流は完全に零となり、発熱体
の温度がそれ以上上昇するのが防止される。Further, for example, when the temperature control device breaks down and the temperature of the heating element is going to be higher than the set temperature, the safety device operates and the current path of the heating element becomes an open circuit. Further, since the current path of the shunt circuit also becomes an open circuit in conjunction with the operation of the safety device, the current flowing through the heating element becomes completely zero, and the temperature of the heating element is prevented from further rising.
たとえば、分流回路としてヒューズを使用した場合、
安全装置の作動によりヒューズに過大な電流が流れ込ん
でヒューズが溶断し、発熱体に流れる電流が完全に阻止
される。For example, if a fuse is used as a shunt circuit,
Due to the operation of the safety device, an excessive current flows into the fuse and the fuse is blown, and the current flowing through the heating element is completely blocked.
以下、図面を参照しながら実施例に基づいて本発明の
特徴を具体的に説明する。Hereinafter, the features of the present invention will be specifically described based on embodiments with reference to the drawings.
第１図は、本実施例における温度制御装置の使用状態
を示す説明図である。なお、第２図に示さされる従来の
温度制御装置に対応する部材等には同一符号を付し、説
明は省略する。FIG. 1 is an explanatory diagram showing a use state of the temperature control device in the present embodiment. Note that the same reference numerals are given to members and the like corresponding to the conventional temperature control device shown in FIG. 2, and description thereof is omitted.
本実施例は、安全装置４に並列にヒューズ５を接続し
ている点が第２図に示す従来例と異なっている。This embodiment is different from the conventional example shown in FIG. 2 in that a fuse 5 is connected in parallel to the safety device 4.
基本的には従来例と同様に、温度センサ６により検出
された加熱ロール１の表面温度に応じて電気回路基板７
によりソリッドステートリレー８のオンオフを制御して
発熱体としての加熱ヒータ２に流れる電流を制御して加
熱ロール１の温度制御を行い、加熱ロール１の表面温度
が190〜200℃程度となるように温度制御している。Basically, similarly to the conventional example, the electric circuit board 7 is provided in accordance with the surface temperature of the heating roll 1 detected by the temperature sensor 6.
The on / off of the solid state relay 8 is controlled by controlling the current flowing through the heater 2 as a heating element to control the temperature of the heating roll 1 so that the surface temperature of the heating roll 1 becomes about 190 to 200 ° C. Temperature controlled.
また、温度制御装置９の故障等により、加熱ロール１
が異常高温となったときは、安全装置４により加熱ヒー
タ２への電流を遮断し、過熱を防止している。Further, due to a failure of the temperature control device 9 or the like, the heating roll 1
When the temperature becomes abnormally high, the safety device 4 cuts off the current to the heater 2 to prevent overheating.
ここで本実施例においては、安全装置４に並列にヒュ
ーズ５を有する分流回路10を接続している。Here, in the present embodiment, a shunt circuit 10 having a fuse 5 is connected to the safety device 4 in parallel.
いま、分流回路10のヒューズ５における溶断電流IMAX
は、加熱ヒータ２に流れる電流をIT、安全装置４に流れ
る電流をIAとすると、 IT−IA＜IMAX＜IT で設定される。Now, the fusing current I MAX in the fuse 5 of the shunt circuit 10
Assuming that the current flowing through the heater 2 is I T and the current flowing through the safety device 4 is I A , it is set as I T −I A <I MAX <I T.
なお、ヒューズ５に流れる電流をIBとすると、 IA＋IB＝IT である。Incidentally, when the current flowing through the fuse 5 and I B, it is I A + I B = I T .
すなわち、安全装置４に流れる電流IAは、加熱ヒータ
２に流れる電流ITよりも小さくなり、したがって、安全
装置４における発熱を抑制することができる。すなわ
ち、安全装置４における発熱量は電流の自乗で影響を受
けるので、電流を少し減少させることによって、発熱量
を大幅に低減することができる。That is, the current I A flowing to the safety device 4 becomes smaller than the current I T flows to the heater 2, thus, it is possible to suppress heat generation in the safety device 4. That is, since the amount of heat generated in the safety device 4 is affected by the square of the current, the amount of heat generated can be significantly reduced by slightly reducing the current.
したがって、安全装置４の作動温度を設定するとき
に、安全装置４自体及び接続部における発熱の影響を受
けることがなく、正確に安全装置４の作動温度が設定で
きる。また、環境の変化或いは安全装置４自体の経時変
化等の影響を受けにくくなる。Therefore, when setting the operating temperature of the safety device 4, the operating temperature of the safety device 4 can be accurately set without being affected by the heat generated in the safety device 4 itself and the connection portion. In addition, it is less susceptible to changes in the environment or changes over time in the safety device 4 itself.
また、温度制御装置９が故障して加熱ロール１が異常
高温となったときには、安全装置４が作動し安全装置４
に流れる電流IAは０となる。したがって、加熱ヒータ２
に流れる電流ITは全てヒューズ５に流れ込む。ヒューズ
５を流れる電流はITとなり溶断電流IMAXより大きくなる
ため、ヒューズ５も溶断し、加熱ヒータ２の電流通路は
完全に遮断され、加熱ロール１の異常過熱が防止され
る。なお、加熱ヒータ２がタングステンランプ等である
場合は、通電開始時に定格電流の約10倍の突入電流が流
れるので、これを考慮してヒューズ５安全装置４の定格
を決める必要がある。When the temperature control device 9 breaks down and the heating roll 1 becomes abnormally high temperature, the safety device 4 is activated and the safety device 4 is activated.
0. The current I A flowing to. Therefore, the heater 2
All current I T flowing to flow into the fuse 5. Since the current flowing through the fuse 5 is larger than I T next fusing current I MAX, the fuse 5 is also blown, the current path of the heater 2 is completely blocked, abnormal overheating of the heating roll 1 is prevented. When the heater 2 is a tungsten lamp or the like, an inrush current of about 10 times the rated current flows at the start of energization. Therefore, it is necessary to determine the rating of the fuse 5 safety device 4 in consideration of this.
なお、分流回路10を複数個設け、安全装置４の作動と
連動して全ての分流回路10を遮断するようにしてもよ
い。このように分流回路10を複数個設けた場合、安全装
置４へ流れる電流がより減少するので安全装置４におけ
る発熱を一層抑えることができる。Note that a plurality of shunt circuits 10 may be provided, and all the shunt circuits 10 may be shut off in conjunction with the operation of the safety device 4. When a plurality of shunt circuits 10 are provided as described above, the current flowing through the safety device 4 is further reduced, so that heat generation in the safety device 4 can be further suppressed.
以上に述べたように、本発明によれば、発熱体に流れ
る電流は分流されて安全装置に流れる。したがって、安
全装置における発熱が大幅に減少し、安全装置の作動温
度の設定を正確に行うことができる。したがって、発熱
体が異常高温になろうとしたとき、早めにすなわち温度
が余り高くならないうちに発熱体への電流供給を停止す
ることができ、他の部品に損傷を与えることもなくな
る。As described above, according to the present invention, the current flowing through the heating element is divided and flows through the safety device. Therefore, heat generation in the safety device is significantly reduced, and the operating temperature of the safety device can be set accurately. Therefore, when the heating element is going to reach an abnormally high temperature, the current supply to the heating element can be stopped early, that is, before the temperature becomes too high, and no damage is caused to other parts.
第１図は本発明実施例の温度制御装置の使用態様を示す
説明図、第２図は従来の温度制御装置の使用態様を示す
説明図である。 1:加熱ロール、2:加熱ヒータ 3:交流電源、4:安全装置 5:ヒューズ、6:温度センサ 7:電気回路基板 8:ソリッドステートリレー 9:温度制御装置、10:分流回路FIG. 1 is an explanatory diagram showing a use mode of a temperature control device according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a use mode of a conventional temperature control device. 1: heating roll, 2: heating heater 3: AC power supply, 4: safety device 5: fuse, 6: temperature sensor 7: electric circuit board 8: solid state relay 9: temperature control device, 10: shunt circuit
Claims (2)
発熱体の温度が設定温度以上となったときに、発熱体か
らの熱を受けて開回路となる安全装置を直列に接続する
と共に、この安全回路に並列に分流回路を接続し、この
分流回路に、前記発熱体に流れる電流から前記安全装置
に流れる電流を差し引いた大きさの電流では開回路とは
ならないが、前記発熱体に流れる電流では開回路となる
特性を持たせたことを特徴とする温度制御装置の保護装
置。1. A safety device which receives heat from a heating element and becomes an open circuit when the temperature of the heating element becomes equal to or higher than a set temperature is connected in series to a current path of the heating element whose temperature is controlled. At the same time, a shunt circuit is connected in parallel to the safety circuit, and a current having a magnitude obtained by subtracting a current flowing through the safety device from a current flowing through the heating element does not constitute an open circuit, but the heating element does not have an open circuit. A protection device for a temperature control device, characterized in that an open circuit is provided with a current flowing through the temperature control device.
徴とする請求項１記載の温度制御装置の保護装置。2. The protection device for a temperature control device according to claim 1, wherein said shunt circuit is a fuse.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63103227A JP2727561B2 (en) | 1988-04-25 | 1988-04-25 | Temperature control device protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63103227A JP2727561B2 (en) | 1988-04-25 | 1988-04-25 | Temperature control device protection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01274617A JPH01274617A (en) | 1989-11-02 |
| JP2727561B2 true JP2727561B2 (en) | 1998-03-11 |
Family
ID=14348592
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63103227A Expired - Fee Related JP2727561B2 (en) | 1988-04-25 | 1988-04-25 | Temperature control device protection device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2727561B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09120230A (en) * | 1995-10-25 | 1997-05-06 | Minolta Co Ltd | Fixing device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5028647A (en) * | 1973-07-20 | 1975-03-24 |
-
1988
- 1988-04-25 JP JP63103227A patent/JP2727561B2/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5028647A (en) * | 1973-07-20 | 1975-03-24 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01274617A (en) | 1989-11-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |