JPH04314078A - Temperature abnormality detector - Google Patents
Temperature abnormality detectorInfo
- Publication number
- JPH04314078A JPH04314078A JP7973191A JP7973191A JPH04314078A JP H04314078 A JPH04314078 A JP H04314078A JP 7973191 A JP7973191 A JP 7973191A JP 7973191 A JP7973191 A JP 7973191A JP H04314078 A JPH04314078 A JP H04314078A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- temperature
- power supply
- detecting
- temperature abnormality
- 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 title claims abstract description 25
- 238000001514 detection method Methods 0.000 claims description 31
- 230000007257 malfunction Effects 0.000 abstract description 5
- 230000002093 peripheral effect Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Landscapes
- Fixing For Electrophotography (AREA)
- Control Of Resistance Heating (AREA)
- Control Of Temperature (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、レーザビームプリンタ
の定着器等の発熱部に用いられ、温度制御を行い、温度
異常を発生したときに制御を遮断する温度異常検出装置
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature abnormality detection device used in a heat generating unit such as a fixing device of a laser beam printer, which controls temperature and shuts off the control when a temperature abnormality occurs.
【０００２】0002
【従来の技術】従来レーザビームプリンタの定着器等に
おいて、温度異常を検出する回路は、サーミスタに代表
される温度検出部と、コンパレータ等による電圧比較部
と、ディジタル回路による制御部によって構成されてい
る。[Prior Art] Conventionally, in a fuser of a laser beam printer, a circuit for detecting temperature abnormality is composed of a temperature detecting section represented by a thermistor, a voltage comparing section using a comparator, etc., and a control section using a digital circuit. There is.
【０００３】以下に従来の温度異常検出装置について説
明する。図３は従来の温度異常検出装置のブロック図で
ある。１は温度検出部であり、２は電圧比較部であり、
３は制御部である。温度検出部１には電圧Ｖｃｃが加え
られ、電圧比較部２には電圧Ｖｐｐが加えられる。A conventional temperature abnormality detection device will be explained below. FIG. 3 is a block diagram of a conventional temperature abnormality detection device. 1 is a temperature detection section, 2 is a voltage comparison section,
3 is a control section. A voltage Vcc is applied to the temperature detection section 1, and a voltage Vpp is applied to the voltage comparison section 2.
【０００４】このように構成された温度異常検出装置に
ついて、その動作を説明する。図４は従来の温度異常検
出装置におけるサーミスタの回路図である。Ｔは周辺温
度によりその抵抗値が変化する素子としてのサーミスタ
であって、温度情報を電圧に変換する。変換方法は、あ
る一定電圧ＶｃｃとサーミスタＴの間に抵抗Ｒ１を入れ
ると、サーミスタＴとグランド（ＧＮＤ ） 間の電圧
Ｖｔ は、サーミスタＴの抵抗値をＲｔ とするとＶｔ
＝｛Ｒｔ ／Ｒ１ ＋Ｒｔ ｝×Ｖｃｃとなる。ここ
で抵抗値Ｒｔ が変化すると、電圧Ｖｔ の値はそれに
応じて変化し、その変化範囲はＧＮＤ 〜Ｖｃｃである
。この電圧Ｖｔ を温度情報電圧とし、図３の電圧比較
部２に入力する。電圧比較部２においては、ＧＮＤ 〜
Ｖｃｃの範囲であらかじめ一定電圧Ｖｒｅｆ を設定す
る。電圧ＶｒｅｆはサーミスタＴの特性と抵抗Ｒ１ に
よって規定される温度情報の基準値であり、この電圧値
に対応する温度を境に温度異常とする。温度異常が発生
した場合には、制御部によって装置の運転を止める等の
対応策を講じる。[0004] The operation of the temperature abnormality detection device configured as described above will be explained. FIG. 4 is a circuit diagram of a thermistor in a conventional temperature abnormality detection device. T is a thermistor as an element whose resistance value changes depending on the ambient temperature, and converts temperature information into voltage. The conversion method is as follows: When a resistor R1 is inserted between a certain voltage Vcc and the thermistor T, the voltage Vt between the thermistor T and the ground (GND) becomes Vt, where the resistance value of the thermistor T is Rt.
= {Rt /R1 +Rt}×Vcc. Here, when the resistance value Rt changes, the value of the voltage Vt changes accordingly, and the range of change is from GND to Vcc. This voltage Vt is used as a temperature information voltage and is input to the voltage comparator 2 in FIG. In the voltage comparator 2, GND ~
A constant voltage Vref is set in advance within the range of Vcc. The voltage Vref is a reference value of temperature information defined by the characteristics of the thermistor T and the resistor R1, and a temperature corresponding to this voltage value is regarded as a temperature abnormality. If a temperature abnormality occurs, the control unit takes countermeasures such as stopping the operation of the device.
【０００５】[0005]
【発明が解決しようとする課題】以上のように構成され
た温度異常検出装置において、図３の電圧比較部２を駆
動させるための電源に、電圧Ｖｃｃとは異なる電圧値Ｖ
ｐｐを設定する。この場合電源立ち上げ時に温度検出部
１の電源電圧Ｖｃｃが電圧比較部２の電源電圧Ｖｐｐよ
りも早く立ち上がると、電圧比較部２の動作電圧が基準
値に達する前に温度検出部１からの入力がある為、比較
結果の出力が定まらず、電圧比較部２が誤動作を起こし
やすい問題点があった。[Problems to be Solved by the Invention] In the temperature abnormality detection device configured as described above, a voltage value V different from the voltage Vcc is applied to the power source for driving the voltage comparator 2 shown in FIG.
Set pp. In this case, if the power supply voltage Vcc of the temperature detection section 1 rises earlier than the power supply voltage Vpp of the voltage comparison section 2 when the power is turned on, the input from the temperature detection section 1 will occur before the operating voltage of the voltage comparison section 2 reaches the reference value. Therefore, there was a problem that the output of the comparison result was not determined and the voltage comparison section 2 was likely to malfunction.
【０００６】[0006]
【課題を解決するための手段】本発明は上記課題を解決
するために、温度検出手段の出力電圧と基準電圧を比較
する電圧比較部の動作電圧が所定値に達したことを検出
したときに、制御部の動作を許可するための許可信号を
出力する電圧検出部を設けたものである。[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides that when it is detected that the operating voltage of a voltage comparison section that compares the output voltage of the temperature detection means and the reference voltage has reached a predetermined value, , is provided with a voltage detection section that outputs a permission signal for permitting operation of the control section.
【０００７】[0007]
【作用】本発明は上記構成により、電圧比較部の動作電
圧が確実に立ち上がった後に、温度の異常検出を開始す
ることによって、電圧比較部の誤動作をなくすものであ
る。According to the above-described structure, the present invention eliminates malfunctions of the voltage comparator by starting temperature abnormality detection after the operating voltage of the voltage comparator has reliably risen.
【０００８】[0008]
【実施例】以下本発明の一実施例について図面を参照し
ながら説明する。図１は本発明の一実施例の温度異常検
出装置のブロック図である。１は温度検出部、２は電圧
比較部、３はディジタル回路による制御部であって、上
述した従来例と同じ構成である。４は電圧比較部２の電
源電圧Ｖｐｐが所定値に達したことを検出し、制御部３
の動作を許可するための許可信号を出力する電圧検出部
である。DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a temperature abnormality detection device according to an embodiment of the present invention. 1 is a temperature detection section, 2 is a voltage comparison section, and 3 is a control section using a digital circuit, which has the same configuration as the conventional example described above. 4 detects that the power supply voltage Vpp of the voltage comparator 2 has reached a predetermined value, and the controller 3
This is a voltage detection unit that outputs a permission signal for permitting the operation of the device.
【０００９】図２は一実施例の温度異常検出装置におけ
る電圧検出部の回路図である。図２において、ＺＮはツ
ェナーダイオードであり、Ｑはトランジスタなどのスイ
ッチング素子である。また、ＮＥＮＢは制御部３の動作
を許可する許可信号であり、この許可信号がローであり
、かつ制御部３の電源Ｖｃｃ がオン状態にならないと
、制御部３は動作しないよう構成されている。電源立ち
上げ時に、電源電圧Ｖｃｃが電源電圧Ｖｐｐよりも早く
立ち上がった場合は、ＮＥＮＢは電源電圧Ｖｃｃの立ち
上がりと同時にハイになる。その後電源Ｖｐｐがツェナ
ーダイオードＺＮで規定された電圧まで達すると、スイ
ッチング素子Ｑがオンになり、信号ＮＥＮＢはローとな
り、制御部３は動作を開始する。電源電圧Ｖｐｐが電源
電圧Ｖｃｃよりも早く立ち上がった場合には、電源Ｖｃ
ｃが立ち上がったときに既にスイッチング素子Ｑはオン
となっており、信号ＮＥＮＢはローとなり、制御部３は
動作を開始する。いずれにしても、電源Ｖｐｐがある一
定電圧に達しない限り制御部３は動作を開始せず、誤動
作を回避できる。FIG. 2 is a circuit diagram of the voltage detection section in the temperature abnormality detection device of one embodiment. In FIG. 2, ZN is a Zener diode, and Q is a switching element such as a transistor. Further, NENB is a permission signal that allows the operation of the control unit 3, and the control unit 3 is configured not to operate unless this permission signal is low and the power supply Vcc of the control unit 3 is turned on. . If the power supply voltage Vcc rises earlier than the power supply voltage Vpp when the power supply is turned on, NENB becomes high at the same time as the power supply voltage Vcc rises. Thereafter, when the power supply Vpp reaches a voltage defined by the Zener diode ZN, the switching element Q is turned on, the signal NENB becomes low, and the control section 3 starts operating. When the power supply voltage Vpp rises earlier than the power supply voltage Vcc, the power supply voltage Vc
When c rises, the switching element Q is already on, the signal NENB becomes low, and the control section 3 starts operating. In any case, the control unit 3 does not start operating unless the power supply Vpp reaches a certain constant voltage, and malfunction can be avoided.
【００１０】0010
【発明の効果】以上説明したように、本発明は温度検出
手段の出力電圧と基準電圧を比較する比較手段の動作電
圧が所定値に達したことを検出した時に、制御部の動作
を許可する許可信号を出力するようにしているため、電
圧比較部の電源電圧が確実に立ち上がった後に、温度の
異常検出を開始することによって、電圧比較部の誤動作
をなくすことができる。[Effects of the Invention] As explained above, the present invention allows the operation of the control section when it is detected that the operating voltage of the comparison means for comparing the output voltage of the temperature detection means and the reference voltage has reached a predetermined value. Since the permission signal is output, malfunction of the voltage comparator can be prevented by starting temperature abnormality detection after the power supply voltage of the voltage comparator has reliably risen.
【図１】本発明の一実施例の温度異常検出装置のブロッ
ク図FIG. 1 is a block diagram of a temperature abnormality detection device according to an embodiment of the present invention.
【図２】一実施例の温度異常検出装置における電圧検出
部の回路図[Fig. 2] Circuit diagram of the voltage detection section in the temperature abnormality detection device of one embodiment
【図３】従来の温度異常検出装置のブロック図[Figure 3] Block diagram of conventional temperature abnormality detection device
【図４】
従来の温度異常検出装置におけるサーミスタの回路図[Figure 4]
Circuit diagram of a thermistor in a conventional temperature abnormality detection device
１ 温度検出部 ２ 電圧比較部 ３ 制御部 ４ 電圧検出部 1 Temperature detection section 2 Voltage comparison section 3 Control section 4 Voltage detection section
Claims (1)
、前記温度検出部からの出力電圧と基準電圧を比較する
電圧比較部と、前記電圧比較部より出力された情報を基
に温度の異常を検知し制御信号を出力する制御部と、前
記電圧比較部の動作電圧が基準値に達したことを検出す
ると前記制御部の動作を許可する許可信号を出力する電
圧検出部を備えたことを特徴とする温度異常検出装置。1. A temperature detection section that outputs a voltage according to temperature; a voltage comparison section that compares the output voltage from the temperature detection section with a reference voltage; a control unit that detects an abnormality and outputs a control signal; and a voltage detection unit that outputs a permission signal that permits operation of the control unit when it detects that the operating voltage of the voltage comparison unit has reached a reference value. A temperature abnormality detection device characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7973191A JPH04314078A (en) | 1991-04-12 | 1991-04-12 | Temperature abnormality detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7973191A JPH04314078A (en) | 1991-04-12 | 1991-04-12 | Temperature abnormality detector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04314078A true JPH04314078A (en) | 1992-11-05 |
Family
ID=13698356
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7973191A Pending JPH04314078A (en) | 1991-04-12 | 1991-04-12 | Temperature abnormality detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04314078A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008202997A (en) * | 2007-02-17 | 2008-09-04 | Seiko Instruments Inc | Temperature detection circuit |
-
1991
- 1991-04-12 JP JP7973191A patent/JPH04314078A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008202997A (en) * | 2007-02-17 | 2008-09-04 | Seiko Instruments Inc | Temperature detection circuit |
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