JP2003302288A - Temperature detection means - Google Patents
Temperature detection meansInfo
- Publication number
- JP2003302288A JP2003302288A JP2002103720A JP2002103720A JP2003302288A JP 2003302288 A JP2003302288 A JP 2003302288A JP 2002103720 A JP2002103720 A JP 2002103720A JP 2002103720 A JP2002103720 A JP 2002103720A JP 2003302288 A JP2003302288 A JP 2003302288A
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- thermistor element
- output voltage
- detection
- film
- 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.)
- Granted
Links
- 238000001514 detection method Methods 0.000 title claims abstract description 47
- 238000010438 heat treatment Methods 0.000 claims abstract description 32
- 238000000034 method Methods 0.000 claims abstract description 10
- 239000000463 material Substances 0.000 description 9
- 238000010586 diagram Methods 0.000 description 8
- 230000007257 malfunction Effects 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000013013 elastic material Substances 0.000 description 2
- 229920001973 fluoroelastomer Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 229920002379 silicone rubber Polymers 0.000 description 2
- 239000004945 silicone rubber Substances 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/20—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat
- G03G15/2003—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat
- G03G15/2014—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat using contact heat
- G03G15/2039—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat using contact heat with means for controlling the fixing temperature
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radiation Pyrometers (AREA)
- Fixing For Electrophotography (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は非接触温度検出手段
を用いた温度検出方法に関し、詳しくは電子写真装置、
静電記録装置等に用いられる定着装置で加熱手段に温度
検知素子を非接触で配置した定着装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature detecting method using a non-contact temperature detecting means, more specifically, an electrophotographic apparatus,
The present invention relates to a fixing device used in an electrostatic recording device or the like in which a temperature detecting element is arranged in a non-contact manner with a heating means.
【０００２】[0002]
【従来の技術】ヒーターにより加熱される定着ローラを
用いた定着装置は、複写機やレーザプリンタ等の画像形
成装置において多用されている。2. Description of the Related Art A fixing device using a fixing roller heated by a heater is widely used in image forming apparatuses such as copying machines and laser printers.
【０００３】このような定着装置では、定着ローラの表
面温度を所定温度に維持するためのサーミスタや、定着
ローラの異常昇温時にヒーターへの通電経路を遮断する
ための温度ヒューズ、サーモスイッチ等の温度検知素子
を定着ローラ表面に当接させている。In such a fixing device, a thermistor for maintaining the surface temperature of the fixing roller at a predetermined temperature, a temperature fuse for shutting off the energizing path to the heater when the temperature of the fixing roller is abnormally elevated, a thermo switch, etc. The temperature detecting element is brought into contact with the surface of the fixing roller.
【０００４】このため、接触キズが定着ローラに発生
し、白スジ，黒スジ，定着不良などの問題が発生するこ
とがある。As a result, contact flaws may occur on the fixing roller, causing problems such as white lines, black lines, and defective fixing.
【０００５】そこで、温度検知手段を、記録材の通過領
域である画像域外において定着ローラに当接させる方法
が考えられるが、画像域内の温度検知が不可能であるこ
とや、定着装置が大型化する為、最近では温度検知手段
を画像域内において定着ローラに非接触に近接させる方
法が考えられている。Therefore, it is conceivable to bring the temperature detecting means into contact with the fixing roller outside the image area, which is the passage area of the recording material, but it is impossible to detect the temperature in the image area, and the fixing device becomes large. Therefore, recently, a method has been considered in which the temperature detecting means is brought into contact with the fixing roller in the image area in a non-contact manner.
【０００６】この非接触温度検知手段は、開口部を有す
るケーシングと、このケーシングに内装されると共に、
開口部を通過した赤外線を吸収する高分子材料から成る
赤外線吸収フィルムと、この赤外線吸収フィルムに密着
するように配設した赤外線検知用のサーミスタ素子と、
ケーシングの温度を検出する温度補償用のサーミスタ素
子を備えたものである。This non-contact temperature detecting means is provided with a casing having an opening, and is installed in the casing.
An infrared absorbing film made of a polymer material that absorbs infrared rays that have passed through the opening, and a thermistor element for infrared detection arranged so as to adhere to the infrared absorbing film,
The thermistor element for temperature compensation for detecting the temperature of the casing is provided.
【０００７】この非接触温度検知手段は、ケーシングの
開口部を通過した赤外線がその開口部の直下に配設した
赤外線吸収フィルムに吸収されることによって赤外線吸
収フィルムの温度が上昇し、赤外線吸収フィルムに密着
して配設したサーミスタ素子がその温度変化を検出す
る。In this non-contact temperature detecting means, the infrared ray which has passed through the opening of the casing is absorbed by the infrared ray absorbing film disposed immediately below the opening, so that the temperature of the infrared ray absorbing film rises and the infrared ray absorbing film is detected. The thermistor element, which is disposed so as to be in close contact with, detects the temperature change.
【０００８】赤外線検知用サーミスタ素子１０と温度補
償用サーミスタ素子１１はともに同等の温度−抵抗特性
のものを使用しており、図６のように同一の抵抗値の固
定抵抗Ｒ１およびＲ２がそれぞれ直列に接続されてい
る。対象物からの赤外線を赤外線吸収フィルムが吸収す
るとフィルムの温度が上昇し、赤外線検知用サーミスタ
の抵抗値が温度補償用サーミスタに比して小さくなるた
め、ａ＞ｂとなっており、出力電圧ａ，ｂをＡ／Ｄコン
バータによりデジタル値に変換してマイクロコンピュー
タに取り込み、マイクロコンピュータはこれらの出力電
圧ａ，ｂのデジタル値をデータテーブルもしくは関数に
より変換して定着ローラの温度を検出している。Both the infrared detecting thermistor element 10 and the temperature compensating thermistor element 11 have the same temperature-resistance characteristics. As shown in FIG. 6, fixed resistors R1 and R2 having the same resistance value are connected in series. It is connected to the. When the infrared absorption film absorbs infrared rays from the object, the temperature of the film rises and the resistance value of the infrared detection thermistor becomes smaller than that of the temperature compensation thermistor, so that a> b, and the output voltage a , B are converted into digital values by an A / D converter and taken into a microcomputer, and the microcomputer detects the temperature of the fixing roller by converting the digital values of these output voltages a, b by a data table or a function. .
【０００９】[0009]
【発明が解決しようとする課題】しかしながら、上記従
来例で説明した非接触温度検知手段を用いた温度検出方
法では、温度の検出に必ずマイクロコンピュータが介在
してしまう。そのため、マイコンのプログラムのバグや
ノイズ等によりマイコンが誤動作した場合、温度検知が
できなくなり、誤動作により間違ってヒータをオンし続
けた場合、サーモスイッチ等の安全装置が働くまで過昇
温し、それが、例えば朝、定着ローラが室温にあるとこ
ろから過昇温した場合には、サーモスイッチの温度が上
がるまで時間がかかるため、その結果、定着ローラや定
着ユニットを損傷してしまう可能性があった。本発明
は、マイコンの介在無しに、非接触温度検知手段の出力
から、定着ローラがある所定の温度となったことを検出
することを可能にし、マイコンが誤動作した場合にも、
サーモスイッチ等の安全装置が働く前に確実にヒータを
オフする方法を提供することが目的である。However, in the temperature detecting method using the non-contact temperature detecting means described in the above-mentioned conventional example, the microcomputer is always involved in the temperature detection. Therefore, if the microcomputer malfunctions due to a bug or noise in the program of the microcomputer, the temperature cannot be detected, and if the heater continues to be turned on by mistake due to malfunction, the temperature rises excessively until a safety device such as a thermoswitch operates. However, for example, if the temperature of the fixing roller rises from room temperature in the morning, it takes time for the temperature of the thermoswitch to rise, and as a result, the fixing roller and fixing unit may be damaged. It was INDUSTRIAL APPLICABILITY The present invention makes it possible to detect that the fixing roller has reached a predetermined temperature from the output of the non-contact temperature detecting means without the intervention of a microcomputer, and even when the microcomputer malfunctions,
It is an object to provide a method for surely turning off a heater before a safety device such as a thermoswitch operates.
【００１０】[0010]
【課題を解決するための手段】上述した目的を達成する
ために、本発明に係わる温度検出方法は、加熱手段から
の赤外線を吸収するフィルムと、フィルムの温度を検知
する赤外線検知用サーミスタ素子と、フィルムを保持す
る保持体の温度を検知する温度補償用サーミスタ素子か
らなる非接触温度検知手段を用いた温度検出方法であっ
て、検出回路が前記赤外線検知用サーミスタ素子と一つ
もしくは複数の抵抗素子の直列回路の第１の出力電圧
と、前記温度補償用サーミスタ素子と一つもしくは複数
の抵抗素子の直列回路の第２の出力電圧を持ち、加熱手
段がある所定の温度の時に、第１の出力電圧と第２の出
力電圧の差分を出力した第３の出力電圧が略一定となる
ように構成することで、第３の出力電圧により前記加熱
手段の温度を検出することを特徴とするものである。In order to achieve the above-mentioned object, a temperature detecting method according to the present invention comprises a film for absorbing infrared rays from a heating means, and an infrared detecting thermistor element for detecting the temperature of the film. A temperature detecting method using a non-contact temperature detecting means composed of a temperature compensating thermistor element for detecting the temperature of a holding body for holding a film, wherein a detection circuit includes the infrared detecting thermistor element and one or more resistors. Having a first output voltage of a series circuit of elements and a second output voltage of a series circuit of the temperature compensating thermistor element and one or a plurality of resistance elements, and the first means when the heating means has a predetermined temperature. The third output voltage, which is the difference between the second output voltage and the second output voltage, is configured to be substantially constant, so that the temperature of the heating means is detected by the third output voltage. It is characterized in.
【００１１】[0011]
【発明の実施の形態】以下本発明の実施の形態を図面に
基づき説明する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.
【００１２】記録紙上の未定着画像を定着させる画像記
録装置は、画像記録装置内部に、図示を省略したが、表
面に静電潜像を形成する像担持体、像担持体の表面の電
荷を除電する前露光手段、像担持体の表面を所望の電位
に帯電させる１次帯電手段、帯電した像担持体上を露光
して静電潜像を形成させる露光手段、像担持体上の静電
潜像を現像剤で現像して可視像化する現像器、現像器で
現像された像担持体上のトナー画像を記録材に転写する
転写装置等が設けられている。また、記録材に転写され
たトナー画像を加熱および加圧された定着ローラにより
溶融定着させるローラ定着装置である定着ユニット１が
画像記録装置の所定位置に配置され、各部材により画像
形成の各プロセスが適宜実行されることにより所望の画
像を得ることができるようになっている。なお、記録材
には記録紙やＯＨＰ用紙などが用いられる。An image recording apparatus for fixing an unfixed image on a recording sheet is provided with an image carrier, which is not shown in the drawing, which forms an electrostatic latent image on the surface of the image carrier, and an electric charge on the surface of the image carrier. Pre-exposure means for removing charge, primary charging means for charging the surface of the image carrier to a desired potential, exposure means for exposing the charged image carrier to form an electrostatic latent image, electrostatic on the image carrier A developing device for developing the latent image with a developer to make it visible, a transfer device for transferring the toner image on the image carrier developed by the developing device to a recording material, and the like are provided. Further, a fixing unit 1 which is a roller fixing device for melting and fixing a toner image transferred onto a recording material by a fixing roller heated and pressed is arranged at a predetermined position of the image recording apparatus, and each member forms each process of image formation. A desired image can be obtained by performing the above. As the recording material, recording paper or OHP paper is used.
【００１３】次に定着ユニット１の構成を説明する。図
２において２は加熱ローラであり、アルミニウム、鉄等
のパイプ材にシリコーンゴム、フッ素ゴム等の耐熱弾性
体の層を形成し表面にＰＦＡ、ＰＴＦＥといった離型層
を被覆したローラである。上記加熱ローラ２に圧接して
配設された加圧ローラ３も加熱ローラと同様に芯金の上
にシリコーンゴム、フッ素ゴム等の耐熱弾性体の層を形
成したローラである。上記加熱ローラ（加熱部材）２と
加圧ローラ（バックアップ部材）３には記録材Ｓが通紙
され、記録材Ｓ上のトナーＴは加熱ローラと加圧ローラ
との間で加熱および加圧されて定着される。Next, the structure of the fixing unit 1 will be described. In FIG. 2, reference numeral 2 is a heating roller, which is a roller in which a layer of a heat resistant elastic material such as silicone rubber or fluororubber is formed on a pipe material such as aluminum or iron, and a release layer such as PFA or PTFE is coated on the surface. Similarly to the heating roller, the pressure roller 3 arranged in pressure contact with the heating roller 2 is also a roller in which a layer of a heat resistant elastic material such as silicone rubber or fluororubber is formed on a core metal. The recording material S is passed through the heating roller (heating member) 2 and the pressure roller (backup member) 3, and the toner T on the recording material S is heated and pressed between the heating roller and the pressure roller. Is established.
【００１４】上記加熱ローラ２の内部にはヒータ４が配
設されており、加熱ローラ２を内部より加熱する。また
上記加熱ローラ２の表面温度を検知するために温度検知
手段たる温度検知素子５が加熱ローラに面して非接触に
配置されており、加熱ローラ２の温度を検出する。温度
検知素子５からのデータに基づいて加熱ローラ２の表面
温度を所定の設定温度（プリント温度）または非定着時
の待機温度（スタンバイ温度）に保つようになってい
る。加熱ローラにはまた、過昇温を検知するため、サー
モスイッチ６が非接触に配設されており、過昇温が検知
された場合、ヒータへの通電を遮断するようになってい
る。A heater 4 is provided inside the heating roller 2 and heats the heating roller 2 from the inside. Further, in order to detect the surface temperature of the heating roller 2, a temperature detecting element 5 serving as a temperature detecting means is arranged in a non-contact manner so as to face the heating roller, and detects the temperature of the heating roller 2. Based on the data from the temperature detection element 5, the surface temperature of the heating roller 2 is maintained at a predetermined set temperature (printing temperature) or a standby temperature during non-fixing (standby temperature). The heating roller is also provided with a thermo switch 6 in a non-contact manner to detect an excessive temperature rise, and when the excessive temperature rise is detected, the energization of the heater is cut off.
【００１５】次に、温度検知素子５の構成について詳細
を図３を用いて説明する。７はアルミ等熱伝導性の高い
材料でできたケースであり、ケースの一面に設けた開口
部８に加熱ローラから放射される赤外光を吸収する耐熱
フィルム９が閉塞するように設けられる。耐熱フィルム
９のケース内面側には、赤外線検知用サーミスタ素子１
０を接着剤等で密着させて固定する。赤外線検知用サー
ミスタ素子１０の近傍には、ケース内の雰囲気温度を測
定するための温度補償用サーミスタ素子１１を配設す
る。赤外線検知用サーミスタ素子１０と温度補償用サー
ミスタ素子１１のリード線１２は、ケース７に設けたソ
ケット（図示なし）にそれぞれ接続して外部に取り出す
ようにする。Next, the structure of the temperature detecting element 5 will be described in detail with reference to FIG. Reference numeral 7 denotes a case made of a material having high thermal conductivity such as aluminum, and a heat-resistant film 9 for absorbing infrared light emitted from the heating roller is provided so as to be closed in an opening 8 provided on one surface of the case. The infrared detection thermistor element 1 is provided on the inner surface of the case of the heat-resistant film 9.
0 is stuck and fixed with an adhesive or the like. In the vicinity of the infrared detection thermistor element 10, a temperature compensating thermistor element 11 for measuring the ambient temperature in the case is arranged. The lead wires 12 of the infrared detection thermistor element 10 and the temperature compensation thermistor element 11 are respectively connected to sockets (not shown) provided in the case 7 so as to be taken out to the outside.
【００１６】次に、温度検知素子５の動作について説明
する。まず、ケース７の開口部８に取り付けた樹脂フィ
ルム９に加熱ローラからの赤外線が入射すると、フィル
ム９に赤外線が吸収されてフィルム９の温度が赤外線量
に応じて上昇する。そして、樹脂フィルム９の温度は、
フィルム裏面に密着固定した赤外線検知用サーミスタ素
子１０に伝導してサーミスタ素子の抵抗変化として検出
する。赤外線検知用サーミスタ素子１０の抵抗は、ケー
スの温度による影響を受けており、その度合いを温度補
償用サーミスタ素子１１を用いて、ケース温度に相当す
る温度を検出している。Next, the operation of the temperature detecting element 5 will be described. First, when infrared rays from the heating roller enter the resin film 9 attached to the opening 8 of the case 7, the infrared rays are absorbed by the film 9 and the temperature of the film 9 rises according to the amount of infrared rays. And the temperature of the resin film 9 is
It is conducted to the infrared detection thermistor element 10 which is closely fixed to the back surface of the film and is detected as a resistance change of the thermistor element. The resistance of the infrared detection thermistor element 10 is affected by the temperature of the case, and the degree of the temperature is detected by the temperature compensating thermistor element 11 to detect the temperature corresponding to the case temperature.
【００１７】ここでケーシングをアルミ等熱伝導性の高
い材料でできたケースにするのは、雰囲気温度の変化に
対する温度補償用サーミスタ素子１１の追従性を向上さ
せる為である。温度検出素子に含まれる２つのサーミス
タは同じ特性のものが使用されており、赤外線検知用サ
ーミスタは対象物からの赤外線を吸収して赤外線吸収フ
ィルムが昇温した分だけ温度補償用サーミスタと比較し
て温度が高くなり、抵抗値は小さくなる。The casing is made of a material having a high thermal conductivity such as aluminum in order to improve the followability of the temperature compensating thermistor element 11 with respect to changes in the ambient temperature. The two thermistors included in the temperature detection element have the same characteristics, and the infrared detection thermistor is compared with the temperature compensation thermistor by the amount that the infrared absorption film absorbs infrared rays from the object and heats up. Temperature rises and the resistance value decreases.
【００１８】この温度検出素子５は自身の温度、すなわ
ち温度補償用サーミスタ素子の温度が０℃から１３０℃
の温度範囲において温度を検出することができるが、こ
のように温度検出素子５自身の温度が大きく変化する場
合、対象物（加熱ローラ）の温度が温度検出素子５に比
して高いと赤外線検知用サーミスタ素子１０の温度は必
ず温度補償用サーミスタ素子の温度より高くなるもの
の、従来例で示した図６の回路における電圧信号ａとｂ
の電位差ｃはたとえ対象物の温度が一定であったとして
も一定ではない。なぜならサーミスタの特性は温度に対
して対数で変化しており、例えば対象物が２２０℃の時
の電位差ｃを図にすると図７のような曲線になるからで
ある。そして、この曲線上で最大の電圧値となる温度補
償用サーミスタが６５℃の電圧値０．２９７Ｖを閾値電
圧として温度検知をすると、図８のように温度補償用サ
ーミスタが１３０℃の場合には、３０４℃で検知するこ
ととなり、希望する対象物温度２２０℃に対して８４℃
もずれた値となってしまう。The temperature detecting element 5 has its own temperature, that is, the temperature of the temperature compensating thermistor element is 0 ° C. to 130 ° C.
However, if the temperature of the temperature detecting element 5 itself greatly changes in this way, if the temperature of the object (heating roller) is higher than that of the temperature detecting element 5, infrared detection is performed. Although the temperature of the thermistor element 10 for use is always higher than that of the temperature compensating thermistor element, the voltage signals a and b in the circuit of FIG.
The potential difference c is not constant even if the temperature of the object is constant. This is because the characteristic of the thermistor changes logarithmically with respect to temperature, and for example, when the potential difference c when the object is 220 ° C. is shown in the figure, a curve as shown in FIG. 7 is obtained. Then, when the temperature compensation thermistor having the maximum voltage value on this curve detects the temperature with the voltage value of 0.297 V of 65 ° C. as the threshold voltage, when the temperature compensation thermistor is 130 ° C. as shown in FIG. , 304 ℃ will be detected, 84 ℃ against the desired target temperature 220 ℃
The value will be off.
【００１９】次にこの温度検知素子５を用いた本発明に
よる温度検出回路を図１を用いて説明する。赤外線検知
用サーミスタ素子１０には直列に抵抗素子Ｒ１が接続さ
れ、電圧信号ｂが取り出されている。２０はＯＰアンプ
によるボルテージフォロワ回路である。一方、温度補償
用サーミスタ素子１１には抵抗素子Ｒ２，Ｒ３が直列に
接続されており、Ｒ２とＲ３の接続点から電圧信号ａが
取り出されている。同様に２１はＯＰアンプによるボル
テージフォロワ回路である。通常のマイコンを使用した
温度制御は、これらの電圧信号ａ，ｂをデジタル値に変
換して行なう。２２は差動増幅回路であり、電圧信号
ａ，ｂを入力とし、ａ−ｂを２０倍に増幅して電圧信号
ｃが出力される。Next, a temperature detecting circuit according to the present invention using the temperature detecting element 5 will be described with reference to FIG. A resistance element R1 is connected in series to the infrared detection thermistor element 10, and a voltage signal b is taken out. Reference numeral 20 is a voltage follower circuit using an OP amplifier. On the other hand, resistance elements R2 and R3 are connected in series to the temperature compensating thermistor element 11, and the voltage signal a is taken out from the connection point of R2 and R3. Similarly, 21 is a voltage follower circuit formed by an OP amplifier. Temperature control using a normal microcomputer is performed by converting these voltage signals a and b into digital values. A differential amplifier circuit 22 receives the voltage signals a and b, amplifies ab 20 times, and outputs a voltage signal c.
【００２０】この実施例では温度補償用サーミスタ素子
１１に直列に接続する抵抗素子を２つにし、それらの値
を適当に設定することで対象物の温度がある所定の温度
の時に電圧信号ａとｂの電位差である差動増幅回路２２
の出力電圧信号ｃが略一定になるようにする。本実施例
では、先の図７で示した特性を持つ温度検出素子５が、
対象物の温度が２２０℃の時に略一定の電圧出力になる
ようなＲ１，Ｒ２，Ｒ３の設定値を求める。In this embodiment, two resistance elements are connected in series to the temperature compensating thermistor element 11 and their values are appropriately set so that when the temperature of the object is a predetermined temperature, the voltage signal a differential amplifier circuit 22 which is the potential difference of b
The output voltage signal c is set to be substantially constant. In this embodiment, the temperature detecting element 5 having the characteristics shown in FIG.
The set values of R1, R2 and R3 are calculated so that the voltage output becomes substantially constant when the temperature of the object is 220 ° C.
【００２１】ここで、一定の電圧出力を期待する温度補
償用サーミスタ素子の温度範囲を２０℃〜１３０℃と
し、抵抗値データとして２０℃、７５℃、１３０℃の温
度補償用サーミスタと赤外線検知用サーミスタの抵抗値
データ（４３８．３ｋ，２７７．８ｋ）、（７１．９
ｋ，５５．３ｋ）、（１８．４ｋ，１６．１ｋ）を使用
する。これらのデータを請求項３で示した式に当ては
め、Ｒ１を３３ｋΩと決めると、Ｒ２とＲ３はそれぞれ
４１．１９ｋΩと３．６７ｋΩになる。そこでＥ９６系
列の抵抗素子から４１．２ｋΩと３．６５ｋΩを選択し
てＲ２，Ｒ３に使用することにすると、対象物が２２０
℃の場合、電圧信号ｃは図４のような特性になる。この
曲線上で電圧出力ｃが最大となるのは、温度補償用サー
ミスタが４５℃の時であり、電位差は２．４５Ｖであ
る。Here, the temperature range of the thermistor element for temperature compensation which expects a constant voltage output is set to 20 ° C. to 130 ° C., and the thermistor for temperature compensation of 20 ° C., 75 ° C. and 130 ° C. and the infrared ray detecting element as resistance value data. Resistance value data (438.3k, 277.8k) of the thermistor, (71.9
k, 55.3k) and (18.4k, 16.1k) are used. Applying these data to the formula shown in claim 3 and setting R1 to 33 kΩ, R2 and R3 are 41.19 kΩ and 3.67 kΩ, respectively. Therefore, if 41.2 kΩ and 3.65 kΩ are selected from the E96 series resistance elements and used for R2 and R3, the target object is 220
In the case of ° C, the voltage signal c has the characteristic shown in Fig. 4. The voltage output c becomes maximum on this curve when the temperature compensation thermistor is at 45 ° C., and the potential difference is 2.45V.
【００２２】そこで、ｄの電圧値を２．４５Ｖに設定す
ると、コンパレータ２３の出力ｅがＨ（５Ｖ）となるこ
とで温度検出することができる。温度補償用サーミスタ
素子が２０℃〜１３０℃の範囲では、このコンパレータ
２３で検出される対象物の温度は図５のようになり、最
大＋１７℃の誤差で温度検出できる。この検出回路は過
昇温検知で使用されるため、最大＋１７℃のずれがあっ
てもサーモスイッチ等で検知するのに比べて十分精度が
高く、しかも、定着ユニットの温度に関わらず検出でき
るため安全上非常に有効である。Therefore, if the voltage value of d is set to 2.45V, the output e of the comparator 23 becomes H (5V), so that the temperature can be detected. When the temperature compensating thermistor element is in the range of 20 ° C. to 130 ° C., the temperature of the object detected by the comparator 23 is as shown in FIG. 5, and the temperature can be detected with a maximum error of + 17 ° C. Since this detection circuit is used for detecting excessive temperature rise, even if there is a maximum deviation of + 17 ° C, it is sufficiently accurate compared to detection with a thermo switch, etc., and it can detect regardless of the temperature of the fixing unit. It is very effective for safety.
【００２３】なお、本実施例では、サーミスタ以外に３
つの抵抗素子を使用する例を説明したが、抵抗値を合わ
せるため、Ｒ１〜３の抵抗素子を複数の抵抗素子の直列
回路あるいは並列回路等で構成しても良い。また、サー
ミスタと抵抗素子の直列回路に更に余分な抵抗素子が挿
入されたとしても、その値がこの回路の検出温度に大き
な影響を与えない程度の小さな抵抗値であるならば、本
構成になんら問題は無いことは当然である。In this embodiment, in addition to the thermistor, 3
Although the example of using one resistance element has been described, the resistance elements R1 to R3 may be configured by a series circuit or a parallel circuit of a plurality of resistance elements in order to match the resistance values. Moreover, even if an extra resistance element is inserted in the series circuit of the thermistor and the resistance element, if the resistance value is a small resistance value that does not significantly affect the detection temperature of this circuit, this configuration will have no effect. Of course, there is no problem.
【００２４】[0024]
【発明の効果】本発明によれば、上述のように非接触温
度検知手段を用いた際に、ハードウェア回路のみである
所定の温度を検出できるため、マイコンの誤動作等があ
った場合にも、装置の安全性を確保できる。According to the present invention, when the non-contact temperature detecting means is used as described above, it is possible to detect a predetermined temperature which is only a hardware circuit. Therefore, even when the microcomputer malfunctions or the like. , The safety of the device can be secured.
【図１】本発明の実施の形態に係る温度検出回路を説明
する図である。FIG. 1 is a diagram illustrating a temperature detection circuit according to an embodiment of the present invention.
【図２】定着ユニット１を説明する図である。FIG. 2 is a diagram illustrating a fixing unit 1.
【図３】温度検知素子５を説明する図である。FIG. 3 is a diagram illustrating a temperature detection element 5.
【図４】図１の検出回路で対象物が２２０℃の場合の電
圧出力を示す図である。FIG. 4 is a diagram showing a voltage output when an object is 220 ° C. in the detection circuit of FIG. 1.
【図５】図１の検出回路で検出電圧を２．４５Ｖに設定
した場合の検出温度を示す図である。5 is a diagram showing a detected temperature when the detection voltage is set to 2.45 V in the detection circuit of FIG.
【図６】従来の検出回路を説明する図である。FIG. 6 is a diagram illustrating a conventional detection circuit.
【図７】従来の検出回路で対象物が２２０℃の場合の電
圧出力を示す図である。FIG. 7 is a diagram showing a voltage output when an object is 220 ° C. in a conventional detection circuit.
【図８】従来の検出回路で検出電圧を０．２９７Ｖに設
定した場合の検出温度を示す図である。FIG. 8 is a diagram showing a detection temperature when a detection voltage is set to 0.297 V in a conventional detection circuit.
１ 定着ユニット ２ 加熱ローラ ３ 加圧ローラ ４ ヒータ ５ 温度検知素子 ６ サーモスイッチ ７ ケース ８ 開口部 ９ 赤外線吸収フィルム １０ 赤外線検出用サーミスタ素子 １１ 温度補償用サーミスタ素子 １２ リード線 ２０ ＯＰアンプ ２１ ＯＰアンプ ２２ 差動増幅回路 ２３ コンパレータ 1 fixing unit 2 heating roller 3 pressure roller 4 heater 5 Temperature sensing element 6 thermo switch 7 cases 8 openings 9 Infrared absorbing film 10 Infrared detection thermistor element 11 Thermistor element for temperature compensation 12 lead wire 20 OP amplifier 21 OP amplifier 22 Differential amplifier circuit 23 Comparator
Claims (3)
ムと、フィルムの温度を検知する赤外線検知用サーミス
タ素子と、フィルムを保持する保持体の温度を検知する
温度補償用サーミスタ素子からなる非接触温度検知手段
を用いた温度検出方法で、 検出回路が前記赤外線検知用サーミスタ素子と一つもし
くは複数の抵抗素子の直列回路の第１の出力電圧と、前
記温度補償用サーミスタ素子と一つもしくは複数の抵抗
素子の直列回路の第２の出力電圧を持ち、加熱手段があ
る所定の温度の時に、第１の出力電圧と第２の出力電圧
の差分を出力した第３の出力電圧が略一定となるように
構成することで、第３の出力電圧により前記加熱手段の
温度を検出することを特徴とする温度検出方法。1. A non-contact temperature comprising a film that absorbs infrared rays from a heating means, an infrared detection thermistor element that detects the temperature of the film, and a temperature compensation thermistor element that detects the temperature of a holding body holding the film. A temperature detection method using a detection means, wherein a detection circuit includes a first output voltage of a series circuit of the infrared detection thermistor element and one or more resistance elements, and one or more of the temperature compensation thermistor element. The third output voltage, which has the second output voltage of the series circuit of the resistance elements and outputs the difference between the first output voltage and the second output voltage when the heating means has a predetermined temperature, becomes substantially constant. With this configuration, the temperature of the heating means is detected by the third output voltage.
ムと、フィルムの温度を検知する赤外線検知用サーミス
タ素子と、フィルムを保持する保持体の温度を検知する
温度補償用サーミスタ素子からなる非接触温度検知手段
を用いた温度検出方法で、 検出回路が前記赤外線検知用サーミスタ素子と一つの抵
抗素子の直列回路の第１の出力電圧と、前記温度補償用
サーミスタ素子と二つの抵抗素子の直列回路の第２の出
力電圧を持ち、加熱手段がある所定の温度の時に、第１
の出力電圧と第２の出力電圧の差分を出力した第３の出
力電圧が略一定となるように構成することで、第３の出
力電圧により前記加熱手段の温度を検出することを特徴
とする温度検出方法。2. A non-contact temperature comprising a film that absorbs infrared rays from the heating means, an infrared detection thermistor element that detects the temperature of the film, and a temperature compensation thermistor element that detects the temperature of a holding body holding the film. In the temperature detection method using a detection means, the detection circuit includes a first output voltage of a series circuit of the infrared detection thermistor element and one resistance element, and a series circuit of the temperature compensation thermistor element and two resistance elements. When the heating means has a second output voltage and the heating means has a predetermined temperature, the first
Is configured so that the third output voltage that outputs the difference between the second output voltage and the second output voltage is substantially constant, and the temperature of the heating means is detected by the third output voltage. Temperature detection method.
素子Ｒ１と、前記温度補償用サーミスタ素子と直列接続
される二つの抵抗素子Ｒ２，Ｒ３が、加熱手段がある所
定の温度の時に、前記非接触温度検知手段が使用される
温度範囲のうちの３つの温度における前記温度補償用サ
ーミスタ素子と前記赤外線検知用サーミスタ素子の抵抗
値の組（Ｒａ１，Ｒｂ１）、（Ｒａ２，Ｒｂ２）、（Ｒ
ａ３，Ｒｂ３）に対して式（Ｒ３＋Ｒａ１）／（Ｒ２＋
Ｒ３＋Ｒａ１）−Ｒｂ１／（Ｒ１＋Ｒｂ１）＝（Ｒ３＋
Ｒａ２）／（Ｒ２＋Ｒ３＋Ｒａ２）−Ｒｂ１／（Ｒ１＋
Ｒｂ２）＝（Ｒ３＋Ｒａ３）／（Ｒ２＋Ｒ３＋Ｒａ３）
−Ｒｂ１／（Ｒ１＋Ｒｂ３）を満たす抵抗値もしくはそ
の近傍の抵抗値で構成されることを特徴とする温度検出
方法。3. The temperature detecting method according to claim 2, wherein a resistance element R1 connected in series with the infrared detection thermistor element and two resistance elements R2, R3 connected in series with the temperature compensation thermistor element, When the heating means has a predetermined temperature, a set of resistance values (Ra1, Ra1) of the temperature compensating thermistor element and the infrared detecting thermistor element in three temperatures within the temperature range in which the non-contact temperature detecting means is used. Rb1), (Ra2, Rb2), (R
a3, Rb3), the formula (R3 + Ra1) / (R2 +
R3 + Ra1) -Rb1 / (R1 + Rb1) = (R3 +
Ra2) / (R2 + R3 + Ra2) -Rb1 / (R1 +
Rb2) = (R3 + Ra3) / (R2 + R3 + Ra3)
A temperature detecting method comprising a resistance value satisfying −Rb1 / (R1 + Rb3) or a resistance value in the vicinity thereof.
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|---|---|---|---|
| JP2002103720A JP3890245B2 (en) | 2002-04-05 | 2002-04-05 | Temperature detection device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002103720A JP3890245B2 (en) | 2002-04-05 | 2002-04-05 | Temperature detection device |
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| Publication Number | Publication Date |
|---|---|
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| JP3890245B2 JP3890245B2 (en) | 2007-03-07 |
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| JP2009163134A (en) * | 2008-01-09 | 2009-07-23 | Canon Inc | Fixing device |
| US7881630B2 (en) | 2005-11-25 | 2011-02-01 | Sharp Kabushiki Kaisha | Temperature control device, temperature control method, fixing device, image forming apparatus, temperature control program, computer-readable recording medium, and computer data signal |
| CN104007645A (en) * | 2013-02-25 | 2014-08-27 | 京瓷办公信息系统株式会社 | Abnormality detection method and abnormality detection device for image forming apparatus, and image forming apparatus |
| WO2017131160A1 (en) * | 2016-01-27 | 2017-08-03 | 三菱マテリアル株式会社 | Temperature detecting circuit |
| US11294312B2 (en) | 2020-03-03 | 2022-04-05 | Brother Kogyo Kabushiki Kaisha | Image forming apparatus to accurately determine temperature of heating member |
| US11402773B2 (en) | 2020-02-07 | 2022-08-02 | Brother Kogyo Kabushiki Kaisha | Fuser |
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2002
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Cited By (9)
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| US7881630B2 (en) | 2005-11-25 | 2011-02-01 | Sharp Kabushiki Kaisha | Temperature control device, temperature control method, fixing device, image forming apparatus, temperature control program, computer-readable recording medium, and computer data signal |
| JP2009163134A (en) * | 2008-01-09 | 2009-07-23 | Canon Inc | Fixing device |
| CN104007645A (en) * | 2013-02-25 | 2014-08-27 | 京瓷办公信息系统株式会社 | Abnormality detection method and abnormality detection device for image forming apparatus, and image forming apparatus |
| JP2014164116A (en) * | 2013-02-25 | 2014-09-08 | Kyocera Document Solutions Inc | Method of detecting break or deviation of heating belt, and image forming apparatus |
| EP2770378A3 (en) * | 2013-02-25 | 2017-08-23 | Kyocera Document Solutions Inc. | Abnormality detection method and abnormality detection device for image forming apparatus, and image forming apparatus |
| WO2017131160A1 (en) * | 2016-01-27 | 2017-08-03 | 三菱マテリアル株式会社 | Temperature detecting circuit |
| US11402773B2 (en) | 2020-02-07 | 2022-08-02 | Brother Kogyo Kabushiki Kaisha | Fuser |
| US11934118B2 (en) | 2020-02-07 | 2024-03-19 | Brother Kogyo Kabushiki Kaisha | Fuser |
| US11294312B2 (en) | 2020-03-03 | 2022-04-05 | Brother Kogyo Kabushiki Kaisha | Image forming apparatus to accurately determine temperature of heating member |
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