JPH04204879A - Heater energizing control system in image forming device - Google Patents

Heater energizing control system in image forming device

Info

Publication number
JPH04204879A
JPH04204879A JP2338477A JP33847790A JPH04204879A JP H04204879 A JPH04204879 A JP H04204879A JP 2338477 A JP2338477 A JP 2338477A JP 33847790 A JP33847790 A JP 33847790A JP H04204879 A JPH04204879 A JP H04204879A
Authority
JP
Japan
Prior art keywords
heater
phase angle
inrush current
value
energization
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
Application number
JP2338477A
Other languages
Japanese (ja)
Inventor
Masahiro Yamamoto
雅洋 山本
Goro Mori
森 五郎
Masaru Takahashi
勝 高橋
Shigeyuki Araki
繁幸 荒木
Toshitaka Senma
俊孝 千間
Tetsuro Sasamoto
哲朗 笹本
Takamasa Hayashi
崇雅 林
Takahito Isobe
卓人 磯部
Masami Miyajima
正巳 宮嶋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP2338477A priority Critical patent/JPH04204879A/en
Publication of JPH04204879A publication Critical patent/JPH04204879A/en
Pending legal-status Critical Current

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  • Control Of Resistance Heating (AREA)
  • Control Of Temperature (AREA)
  • Fixing For Electrophotography (AREA)
  • Control Or Security For Electrophotography (AREA)

Abstract

PURPOSE:To prevent the breakage of the switching element with an inrush current by starting energizing to the heater in a relation of the inrush current value flowing in the heater when energizing is started at a phase angle between 135-180 deg. and a current value at a phase angle of 270 deg.. CONSTITUTION:With such a phase angle that the inrush current value flowing in the heater when energying is started at an optional phase angle between 135-180 deg. and by subsequently continuing to energize the electric current value at a phase angle of 270 deg. are the same value, energizing to the heater 2 starts. Namely by starting to energize the heater 2 a little before the voltage of the alternate current power source 1 is 0V (0-45 deg.), the voltage value at the power source 1 at that time is low, so that the inrush current value can be suppressed at a low value. Also the time until the phase angle of 270 deg. of the next maximum voltage point arrives, is longer than the time starting the energizing at 0 volt, so that the temp. raise during that time is also larger and the resistance value of the heater 2 also increases and the entry electric current is suppressed low. Hence the breakage of the switching element due to the inrush current is prevented.

Description

【発明の詳細な説明】 〔発明の詳細な説明〕 この発明は、複写機、レーザプリンタ、ファクシミリ装
置等の電子写真方式を用いた画像形成装置におけるヒー
タ通電制御方式に関する。
DETAILED DESCRIPTION OF THE INVENTION [Detailed Description of the Invention] The present invention relates to a heater energization control method in an image forming apparatus using an electrophotographic method, such as a copying machine, a laser printer, or a facsimile machine.

〔従来の技術〕[Conventional technology]

一般に、複写機のような画像形成装置においては、感光
体面から転写紙上に転写された未定着トナー像を定着さ
せるために、定着ローラを用いて加熱定着して定着させ
る定着装置が使用されている。
Generally, in an image forming apparatus such as a copying machine, a fixing device is used that uses a fixing roller to heat and fix an unfixed toner image transferred from a photoreceptor surface onto a transfer paper. .

そして、この定着装置における定着ローラは内蔵のヒー
タによって加熱され、その定着ローラの表面温度を一定
に保持するように、定着温度制御回路によってヒータへ
の通電をオン・オフ制御している。
The fixing roller in this fixing device is heated by a built-in heater, and a fixing temperature control circuit controls on/off power supply to the heater so as to keep the surface temperature of the fixing roller constant.

ところで、定着装置が冷えた状態にある時に、交流電源
を電源とする定着ローラ内のヒータをオンにすると、そ
の抵抗値が下がっているためにヒータに流れる電流は非
常に大きくなる。
By the way, if the heater in the fixing roller, which is powered by an AC power source, is turned on when the fixing device is in a cold state, the current flowing through the heater becomes very large because its resistance value has decreased.

したがって、ヒータをオン・オフするトライアック等の
スイッチング素子がその突入を流により破壊されたり、
あるいは破壊しないような定格電流の大きいスイッチン
グ素子を使用しなければならないなどの欠点があった。
Therefore, switching elements such as triacs that turn on and off the heater may be destroyed by the current, or
Another disadvantage is that a switching element with a large current rating must be used to avoid destruction.

第4図(イ)に、特に電流の大きくなる交流電圧の位相
角90°でスイッチをオン(ヒータへの通電開始)にし
た時のヒータに流れる電流の様子を示す。
FIG. 4(a) shows the state of the current flowing through the heater when the switch is turned on (starting energization of the heater) at a phase angle of 90° of the AC voltage where the current becomes particularly large.

スイッチ・オン時(位相角90°)はヒータの抵抗値が
小さいため突入電流量は非常に大きい。
When the switch is on (phase angle 90°), the resistance value of the heater is small, so the amount of rush current is very large.

そして、ヒータへの通電を続けるうちに、発熱により抵
抗値は大きくなり電流値は小さくなっていく。つまり、
このスイッチ・オン時の過電流によりスイッチング素子
が破壊されてしまうことがある。なお、図中のPeak
 1はその突入電流の最大値を示している。
Then, as the heater continues to be energized, the resistance value increases due to heat generation, and the current value decreases. In other words,
The switching element may be destroyed by this overcurrent when the switch is turned on. In addition, Peak in the figure
1 indicates the maximum value of the inrush current.

そこで、このような欠点を解消するために、交流電圧が
0V(位相角0°)の時にスイッチをオンにし、突入電
流を下げる方法が考えられる。
Therefore, in order to eliminate such drawbacks, a method can be considered in which the switch is turned on when the AC voltage is 0 V (phase angle 0°) to reduce the rush current.

Ovでスイッチをオンにした時の電流波形を第4図(ロ
)に示す。
Figure 4 (b) shows the current waveform when the switch is turned on at Ov.

つまり、Ovでスイッチをオンにした後、最初の電圧ピ
ーク点の位相角90’で電流もピークに達するが、スイ
ッチ・オン時から位相角90″に達するまでの間にヒー
タは熱上昇し、抵抗値は下がる。
In other words, after turning on the switch at Ov, the current also reaches its peak at the phase angle of 90' which is the first voltage peak point, but the heater heats up from the time the switch is turned on until it reaches the phase angle of 90'. The resistance value decreases.

したがって、突入電流の最大値はPeak 2で示すよ
うにゼロクロスでスイッチしない場合より小さく抑える
ことができる6 〔発明が解決しようとする課題〕 しかしながら、上述のような突入電流による素子破壊の
危険はなお存在し、さらに突入電流を下げる必要がある
Therefore, the maximum value of the inrush current can be suppressed to be smaller than that in the case of not switching at zero cross, as shown by Peak 2.6 [Problem to be solved by the invention] However, there is still a risk of element destruction due to the above-mentioned inrush current. exists, and it is necessary to further reduce the inrush current.

この発明は上記の問題点に鑑みてなされたものであり、
定着ヒータへの通電開始時における突入電流を下げ、突
入電流によるスイッチング素子の破壊をより確実性をも
って防止できるようにすることを目的とする。
This invention was made in view of the above problems,
It is an object of the present invention to reduce the inrush current at the time of starting energization to a fixing heater, and to more reliably prevent destruction of a switching element due to the inrush current.

〔課題を解決するための手段〕[Means to solve the problem]

この発明は上記の目的を達成するため、電子写真方式に
よる画像形成装置で、未定着トナーを熱定着する定着装
置における定着ローラ内のヒータへの通電をオン・オフ
制御するヒータ通電制御方式において、商用交流電源の
AC0V点を位相角0″として、135”〜18o′の
間にある任意の位相角で通電を開始した時のヒータへ流
れる突入電流値を工、とし、その後通電し続けて位相角
270°での電流値を工2とした時、I、=I1=I2
となるような位相角でヒータへの通電を開始するように
したものである。
In order to achieve the above object, the present invention provides a heater energization control method for controlling on/off energization of a heater in a fixing roller in a fixing device that thermally fixes unfixed toner in an electrophotographic image forming apparatus. Let the AC0V point of the commercial AC power supply be the phase angle 0'', and let the value of rush current flowing to the heater when energization is started at an arbitrary phase angle between 135'' and 18o' be , and then continue to energize to change the phase. When the current value at an angle of 270° is 2, I, = I1 = I2
The heater is designed to start energizing at a phase angle such that .

〔作 用〕[For production]

この発明によるヒータ通電制御方式では、135°〜1
80°の間にある任意の位相角で通電を開始した時のヒ
ータへ流れる突入電流値と、その後通電し続けて位相角
270°での電流値とが同じ値になるような位相角でヒ
ータへの通電を開始する。
In the heater energization control method according to the present invention, 135° to 1
The heater is set at a phase angle such that the inrush current value flowing into the heater when energization is started at an arbitrary phase angle between 80° and the current value at a phase angle of 270° after continuing energization are the same value. Start energizing.

すなわち、交流電源の電圧ovより少しくQ〜45°)
前でヒータへの通電を開始することにより、その時の電
源の電圧値が低いため突入電流を低く抑えることができ
る。
In other words, Q~45°, which is slightly lower than the voltage ov of the AC power supply)
By starting energizing the heater at the front, the inrush current can be kept low because the voltage value of the power supply at that time is low.

また、次の電圧ピーク点である位相角2701に達する
までの時間がovで通電を開始した時より長くなるため
、その間の温度上昇も大きくなってヒータの抵抗値も上
がり、突入電流を低く抑えることができる。
Additionally, since the time it takes to reach phase angle 2701, which is the next voltage peak point, is longer than when energization is started at ov, the temperature rise during that time also increases and the resistance value of the heater increases, keeping the inrush current low. be able to.

したがって、上述の各突入電流値が等しくなるような位
相角でヒータへの通電を開始することにより、突入電流
によるスイッチング素子の破壊を確実性をもって防ぐこ
とができる。
Therefore, by starting energization to the heater at a phase angle such that the above-mentioned inrush current values become equal, it is possible to reliably prevent destruction of the switching element due to inrush current.

〔実施例〕〔Example〕

以下、この発明の実施例を図面に基づいて具体的に説明
する。
Embodiments of the present invention will be specifically described below with reference to the drawings.

第1図は、この発明の一実施例である画像形成装置にお
ける定着温度制御回路の構成を示す回路図である。
FIG. 1 is a circuit diagram showing the configuration of a fixing temperature control circuit in an image forming apparatus that is an embodiment of the present invention.

この定着温度制御回路において、1は交流@、源。In this fixing temperature control circuit, 1 is an AC @ source.

2は定着装置内における定着ローラを加熱するヒータ、
3は交流電源1からヒータ2への通電をオン・オフする
トライアック、4は交流電源1による交流電圧のゼロク
ロス電圧(0V)を検知するゼロ電圧検知回路、5は定
着ローラの表面温度を常に一定に保つようにヒータ2へ
の通電をオン・オフ制御する定着温度制御用コントロー
ラである。
2 is a heater that heats the fixing roller in the fixing device;
3 is a triac that turns on and off the power supply from AC power supply 1 to heater 2; 4 is a zero voltage detection circuit that detects the zero cross voltage (0V) of the AC voltage from AC power supply 1; 5 is a circuit that keeps the surface temperature of the fixing roller constant. This is a controller for controlling the fixing temperature, which controls on/off the supply of electricity to the heater 2 so as to maintain the temperature at a constant temperature.

コントローラ5は、定着ローラの表面温度が規定温度以
下になると、ヒータ2への通電をオンにする信号を出力
するが、そのタイミングはゼロ電圧検知回路4でゼロク
ロス電圧を検知した後、タイマ7で位相角がA、’(=
135°〜180’ の間にある任意の位相角)になる
時間をカウントし、A工° に達した時にタイマ7によ
り出力された信号でヒータ2への通電を開始し、その後
定着ローラの表面温度が規定温度に達するまで通電し続
ける。
When the surface temperature of the fixing roller falls below a specified temperature, the controller 5 outputs a signal to turn on the power to the heater 2, but the timing is determined by the timer 7 after the zero voltage detection circuit 4 detects the zero cross voltage. The phase angle is A,'(=
The time when the phase angle reaches an arbitrary phase angle between 135° and 180' is counted, and when the phase angle A is reached, the heater 2 is started to be energized by the signal output by the timer 7, and then the surface of the fixing roller is Continue to energize until the temperature reaches the specified temperature.

なお、コントローラ5の出力はフォトトライアック6に
接続されており、フォトトライアック6゜はトライアッ
ク3に接続されているため、コントローラ5の制御によ
りヒータ2への通電をオン・オフ駆動することができる
Note that since the output of the controller 5 is connected to the phototriac 6, and the phototriac 6° is connected to the triac 3, the power supply to the heater 2 can be turned on and off under the control of the controller 5.

第2図に、位相角0’  (0V)7り1ら150°位
相をずらしてヒータ2への通電を開始した時の突入電流
波形を示す。
FIG. 2 shows an inrush current waveform when energization to the heater 2 is started with a phase shift of 150 degrees from 7 to 1 at a phase angle of 0' (0V).

位相角150゛でスイッチをオン(ヒータへの通電開始
)にした時の突入電流の最大値をPeak 3とする位
相角150°での電圧値は、A C電圧のピーク値の1
 / 2 (=sin 150°)であるため、突入電
流の最大値Peak 3は第4図(イ)に示したpea
k 1の1/2になる。
The voltage value at a phase angle of 150° is 1 of the peak value of the AC voltage, where Peak 3 is the maximum value of the inrush current when the switch is turned on (starting energizing the heater) at a phase angle of 150°.
/ 2 (=sin 150°), so the maximum value of inrush current Peak 3 is pea shown in Figure 4 (A).
It becomes 1/2 of k1.

また、位相角270°での突入電流の最大値をPaak
 4とすると、位相角150’−270’ までの間の
通電によるヒータ2の温度上昇により、ヒータ2の抵抗
値は小さくなり、Paak4の値も小さくなる。
Also, the maximum value of inrush current at a phase angle of 270° is Paak
4, the resistance value of the heater 2 decreases and the value of Paak4 also decreases due to the temperature rise of the heater 2 due to energization during a phase angle of 150'-270'.

第4図(ロ)に示したPeak 2の場合は、位相角0
°から90’ の通電後にピークを迎えるのに対し、P
eak 4は150°から270°の通電後にピークに
なるため、そのピークを迎える前の予熱量(通電量)は
、位相角15o°で通電を開始した方が当然大きくなる
In the case of Peak 2 shown in Figure 4 (b), the phase angle is 0.
P
Since eak 4 reaches its peak after energization from 150° to 270°, the amount of preheating (amount of energization) before reaching the peak is naturally larger when energization is started at a phase angle of 15°.

よって、温度上昇天となり、抵抗値は低くなるため、P
eak 2 )Peak 4となる。
Therefore, the temperature rises and the resistance value decreases, so P
eak 2 ) Peak 4.

さて、位相角135°〜180°のどこでヒータ2への
通電をオンにするかは、ヒータ2の特性。
Now, the characteristic of the heater 2 determines where in the phase angle of 135° to 180° energization to the heater 2 is turned on.

特に通電量に対する抵抗値の変化の特性によって決定さ
れる。
In particular, it is determined by the characteristics of the change in resistance value with respect to the amount of current applied.

交流電圧Ovポイントより位相角A°でヒータ2への通
電を開始した時のPeak 3とPeak 4の値は。
What are the values of Peak 3 and Peak 4 when electricity is started to the heater 2 at a phase angle of A° from the AC voltage Ov point?

位相角A°が変化することにより第3図に示すように変
化する。但し、Peak 4は実際には負電流であるが
、説明を簡単にするために絶対値として示している。
As the phase angle A° changes, it changes as shown in FIG. However, although Peak 4 is actually a negative current, it is shown as an absolute value to simplify the explanation.

位相角90°でのPeak 3が第4図(イ)のPea
klに等しく1位相角180° (=O”)でのPaa
k4が同図(ロ)のPeak 2に等しくなる。
Peak 3 at a phase angle of 90° is Pea in Figure 4 (a).
Paa at one phase angle of 180° (=O”) equal to kl
k4 becomes equal to Peak 2 in the same figure (b).

したがって、Peak 3とPeak 4の交点となる
位相角A工° でヒータ2への通電を開始すれば、Pe
akl >Peak 2 >Peak 3 = Pea
k 4となり、ヒータ2への通電開始時の突入電流を最
も効果的に下げることができる。
Therefore, if we start energizing the heater 2 at the phase angle A which is the intersection of Peak 3 and Peak 4, the Pe
akl > Peak 2 > Peak 3 = Pea
k 4, and the inrush current at the start of energization to the heater 2 can be most effectively lowered.

〔発明の効果〕〔Effect of the invention〕

以上説明したように、この発明によれば、定着ヒータへ
の通電開始時における突入電流をより効果的に下げるこ
とができるので、突入電流によるスイッチング素子の破
壊をより確実性をもって防止することができる。
As described above, according to the present invention, it is possible to more effectively reduce the inrush current at the start of energization to the fixing heater, so it is possible to more reliably prevent destruction of switching elements due to inrush current. .

【図面の簡単な説明】[Brief explanation of the drawing]

第1図はこの発明の一実施例である画像形成装置におけ
る定着温度制御回路の構成を示す回路図。 第2図はこの実施例により定着ヒータへの通電を開始し
た時の電流波形を示す線図、 第3図はこの実施例の作用説明に供する線図、第4図は
従来の定着温度制御回路により定着ヒータへの通電を開
始した時の電流波形の異なる例を示す線図である。 1・・・交流電源      2・・・ヒータ3・・・
トライアック    4・・・ゼロ電圧検知回路5・・
・定着温度制御用コントローラ 6・・・フォトトライアック 7・・・タイマ出願人 
株式会社 リ  コ  − −一第3図 第2図 P頭に3 7′ 第4図
FIG. 1 is a circuit diagram showing the configuration of a fixing temperature control circuit in an image forming apparatus that is an embodiment of the present invention. Fig. 2 is a diagram showing the current waveform when electricity is started to be applied to the fixing heater according to this embodiment, Fig. 3 is a diagram used to explain the operation of this embodiment, and Fig. 4 is a conventional fixing temperature control circuit. FIG. 4 is a diagram showing different examples of current waveforms when energization to the fixing heater is started. 1... AC power supply 2... Heater 3...
Triac 4...Zero voltage detection circuit 5...
-Fusing temperature controller 6...Phototriac 7...Timer applicant
Rico Co., Ltd. - -1 Figure 3 Figure 2 P head 3 7' Figure 4

Claims (1)

【特許請求の範囲】 1 電子写真方式による画像形成装置で、未定着トナー
を熱定着する定着装置における定着ローラ内のヒータへ
の通電をオン・オフ制御するヒータ通電制御方式におい
て、 商用交流電源のAC0V点を位相角0°として、135
°〜180°の間にある任意の位相角で通電を開始した
時の前記ヒータへ流れる突入電流値をI_1とし、その
後通電し続けて位相角270°での電流値をI_2とし
た時、I_1=I_2となるような位相角で前記ヒータ
への通電を開始することを特徴とするヒータ通電制御方
式。
[Scope of Claims] 1. In an electrophotographic image forming apparatus, in a heater energization control method that controls on/off energization to a heater in a fixing roller in a fixing device that thermally fixes unfixed toner, Assuming the AC0V point as the phase angle of 0°, 135
Let I_1 be the inrush current value flowing into the heater when energization is started at an arbitrary phase angle between 180° and 180°, and let I_2 be the current value at a phase angle of 270° after continuing energization, I_1 A heater energization control method characterized in that energization to the heater is started at a phase angle such that =I_2.
JP2338477A 1990-11-30 1990-11-30 Heater energizing control system in image forming device Pending JPH04204879A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2338477A JPH04204879A (en) 1990-11-30 1990-11-30 Heater energizing control system in image forming device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2338477A JPH04204879A (en) 1990-11-30 1990-11-30 Heater energizing control system in image forming device

Publications (1)

Publication Number Publication Date
JPH04204879A true JPH04204879A (en) 1992-07-27

Family

ID=18318529

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2338477A Pending JPH04204879A (en) 1990-11-30 1990-11-30 Heater energizing control system in image forming device

Country Status (1)

Country Link
JP (1) JPH04204879A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0875804A1 (en) * 1997-04-30 1998-11-04 Canon Kabushiki Kaisha Heater control device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0875804A1 (en) * 1997-04-30 1998-11-04 Canon Kabushiki Kaisha Heater control device
US6157010A (en) * 1997-04-30 2000-12-05 Canon Kabushiki Kaisha Heater control device

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