JP2004296166A

JP2004296166A - Heating device, fixing device using it, and image forming device using the fixing device

Info

Publication number: JP2004296166A
Application number: JP2003084358A
Authority: JP
Inventors: Kazuto Kishi; 和人岸; Yasuhisa Kato; 泰久加藤; Akiyasu Amita; 晃康網田; Masami Okamoto; 政己岡本; Takatada Tsukioka; 誉唯月岡; Hirotada Takagi; 啓正高木
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2003-03-26
Filing date: 2003-03-26
Publication date: 2004-10-21

Abstract

<P>PROBLEM TO BE SOLVED: To adjust a power supply amount from a power storage device to a heating element of a heating portion to a state for supplying only necessary power amount or to a state close to that state in a heating device which is used for a fixing device of an image forming device etc. and uses the power storage device. <P>SOLUTION: A heating portion 2 is provided with the main heating element 2a and an auxiliary heating element 2b; the main power supply device 3 supplies power to the heating element 2a; and an auxiliary power supply device 4 using an electric double-layer capacitor supplies power to the heating element 2b. A CPU 10 of a control means 8 calculates a necessary calorie so that an object to be heated X is set to a setting temperature, controls to increase or decrease the supply of the power from a capacitor C of the power supply device 4 to the heating element 2b and accurately controls the power supply amount. For the calculation of the necessary calorie by the CPU 10, if the object X is a recording medium of paper etc., its number of passing sheets, gloss, color, temperature, environmental temperature of circumferences, and surface characteristics are used. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、例えば各種材料や装置を加熱する加熱装置と、これを用いた定着装置及びこの定着装置を用いた電子写真方式の複写機、プリンタ、ファクシミリ等の画像形成装置に関し、特にこれら装置の省電力の効率化を図ったものに関する。
【０００２】
【従来の技術】
複写機等の画像形成装置には、普通紙やＯＨＰ等の記録媒体上に画像を形成するが、画像形成の高速性や画像品質、コスト等から電子写真方式が多く採用されている。電子写真方式は、記録媒体上にトナー像を形成し、形成したトナー像を熱と圧力で記録媒体に定着する方法である。定着方式としては、安全性等の面からヒートローラ方式が現在最も多く採用されている。ヒートローラ方式は、ハロゲンヒータ等の発熱部材により加熱する加熱ローラと、加熱ローラに対向配置する加圧ローラを圧接してニップ部と称される相互圧接部を形成し、このニップ部にトナー像が転写された記録媒体を通して加熱、加圧するもので、これによりトナーを記録媒体に定着させる。
【０００３】
近年、環境問題が重要となり、複写機やプリンタ等の画像形成装置も省エネルギ化が進んでいる。この画像形成装置の省エネルギを考えるに当たって無視できないのは、トナーを記録媒体に定着する定着装置の省電力である。そこで、画像形成装置の待機時における定着装置の消費電力の低減としては、待機時には加熱ローラの温度を定着温度よりやや低い一定の温度に保っておき、使用時に直ちに使用可能温度まで立ち上げ、使用者が定着ローラの昇温を待つことがないようにする方式が多く採用されている。この方式の場合、定着装置を使用していないときにもある程度の電力を供給しておかなければならず、それによって余分なエネルギを消費するようになっている。この待機時の消費エネルギは、画像形成装置を構成する機器の消費エネルギの約７割から８割に該当すると言われている。
【０００４】
したがって、待機時の消費エネルギを削減し、より省電力化を図ることが望まれるようになってきており、未使用時には電力供給をゼロにすることが求められている。しかしながら、待機時にエネルギ消費をゼロにすると、定着装置の加熱ローラは鉄やアルミ等の金属ローラを主に使用していて熱容量が大きいため、約１８０℃前後の使用可能温度にまで昇温するには数分から十数分という長い加熱時間が必要になる。このような待ち時間は、使用者の使い勝手を悪化させてしまうので、消費電力が極力小さく、その一方で待機状態からの立ち上がりが速い加熱方式が望まれている。
【０００５】
加熱ローラの昇温時間を短くするためには、単位時間の投入エネルギ、すなわち定格電力を大きくすると良いことは明らかであり、実際に、プリント速度が速い高速機と称される画像形成装置には、電源電圧を２００Ｖにして対応しているものも多い。しかしながら、日本国内の一般的なオフィスでは、商用電源は１００Ｖ、１５Ａであり、２００Ｖに対応させるには設置場所の電源関連設備に特別な工事を施す必要があり、２００Ｖへの対応化はあまり一般的な解決法とはいえない。
【０００６】
すなわち、１００Ｖ、１５Ａの商用電源を使用するかぎり、加熱ローラを短時間で昇温させようとしても、最大投入エネルギーが電源により決まってしまうので、これを改善するために、定着装置が待機状態になったときに一定レベルだけ低い電圧を加熱ローラに供給して定着装置の温度が下がることを遅らせたり（例えば特許文献１参照）、定着装置の待機時に補助電源である二次電池を充電し、定着装置を立ち上げたときに主電源装置と二次電池や一次電池から電力を供給して立ち上がり時間を短縮するようにしたり（例えば特許文献２参照）している。
【０００７】
しかし、特許文献１に示された技術は、待機時においても定着装置に一定レベルだけ低い電圧を供給しているため、十分な省電力とはいえないものとなっている。また、立ち上げ時の最大供給電力を主電源装置から供給する電力より高めることを主にしたものではない。一方、特許文献２に示された定着装置は、立ち上げ時に主電源装置と二次電池や一次電池から電力を供給しており、二次電源としては一般に鉛蓄電池、ニカド電池、ニッケル水素電池を使用している。このような二次電池は、充放電を繰り返すと容量が劣化して低下していき、大電流で放電するほど寿命が短いという性質を持つ。またメモリ効果による容量低下という現象もある。一般的に大電流で長寿命とされているものでも、充放電の繰り返し回数は約５００〜１０００回程度であり、一日に２０回の充放電を繰り返すと一ヶ月程度で電池の寿命が来てしまうことになる。したがって電池の交換頻度が多くなり、そのぶん手間がかかり、交換する電池代等のランニングコストもかさむ。さらに鉛蓄電池では電解液に液体の硫酸を使用する等、オフィス用機器としては好ましくない点もある。
【０００８】
また、大電力の供給を開始したり停止したりする際の急激な電流変化や突入電力等により加熱ローラが内蔵している加熱用回路への負荷が増大するとともに、周辺回路にも投入電流が流れてノイズが発生するという問題もある。このため、大容量の補助電源からの電力供給を頻繁にオン、オフさせることは好ましくない。また、大容量の電力を一度に供給すると供給過剰になり、加熱用回路の温度が上昇しすぎる可能性もある。
【０００９】
このような点を改善し、省電力効果を高めるとともに、大電力を供給する際の突入電流や急激な電流変化によるノイズを低減させ、かつ立ち上がり時間を短縮し、温度が上がりすぎることを防止することができる定着装置として、補助電源装置に充放電可能なキャパシタを使用し、充電器は主電源装置から供給される電力で補助電源装置のキャパシタを充電し、切替装置は補助電源装置の充電と補助電源装置からの補助発熱体に対する電力供給を切り替え、補助電源装置から補助発熱体に供給する電力量を調整する装置が提案されている（例えば特許文献３参照）。
【００１０】
この特許文献３に示されている装置は、商用電源から供給する電力により発熱する主ヒータと、キャパシタを用いた補助電源装置から供給する電力により発熱する補助ヒータを有し、被加熱体である定着装置の加熱ローラを加熱できるようにしたものである。補助電源装置には、２０００Ｆ程度の静電容量を有し、数秒から数１０秒の電力供給には十分な容量を備えている充放電可能な電気二重層キャパシタ（あるいはキャパシタ）等を使用するようになっており、例えば供給電力を遮断するタイミングにより補助電源装置から補助発熱体へ供給する電力をオン、オフさせて供給電力量を調整している。
【００１１】
【特許文献１】
特開平１０−１０９１３号公報
【特許文献２】
特開平１０−２８２８２１号公報
【特許文献３】
特開２００２−１８４５５４号公報
【００１２】
【発明が解決しようとする課題】
ところでキャパシタの基本機能としては、キャパシタから供給する電力によって補助ヒータを発熱させ、この熱を用いて加熱ローラが所定温度まで立ち上る時間を短縮すること、及び通紙時の定着温度の低下を防止することであるが、蓄電装置から発熱体への電力供給は、必要な電力量のみ行うことが望ましく、特許文献３に開示されている技術のように供給電力を遮断するタイミングにより供給電力量を調整するだけでは実現できないものとなっている。
【００１３】
本発明は上記従来の諸問題点を解決できる加熱装置、これを用いた定着装置及びこの定着装置を用いた画像形成装置を提供することを目的とする。
【００１４】
【課題を解決するための手段】
本発明に係る加熱装置のうち請求項１に係るものは、上記目的を達成するために、加熱部、該加熱部に電力を供給して加熱するための蓄電装置、及び該蓄電装置の動作を制御する制御手段を有し、上記加熱部が、上記蓄電装置から供給される電力により発熱する発熱体を有し、上記蓄電装置が充放電可能なキャパシタを備える加熱装置において、上記制御手段は、上記被加熱体を設定温度にするために必要な熱量を演算する演算手段を備え、該演算手段により演算した熱量に基づき、上記蓄電装置から上記発熱体への電力供給量を調整する制御を行うものであることを特徴とする。
【００１５】
同請求項２に係るものは、上記目的を達成するために、請求項１の加熱装置において、上記制御手段は、上記発熱体により加熱される被加熱体の設定温度または該被加熱体の検知温度に基づいて制御するものであることを特徴とする。
【００１６】
同請求項３に係るものは、上記目的を達成するために、請求項２の加熱装置において、上記被加熱体の検知温度に基づいて制御する場合、上記検知温度を、電力供給開始時の温度または電力供給開始後に変化した温度のいずれかとすることを特徴とする。
【００１７】
同請求項４に係るものは、上記目的を達成するために、請求項２または３の加熱装置において、上記制御手段は、上記被加熱体の設定温度と該被加熱体の検知温度の対比結果に基づいて制御するものであることを特徴とする。
【００１８】
同請求項５に係るものは、上記目的を達成するために、請求項１の加熱装置において、上記制御手段は、上記蓄電装置の保有電力量に応じて制御するものであることを特徴とする。
【００１９】
同請求項６に係るものは、上記目的を達成するために、請求項１ないし５のいずれかの加熱装置において、上記演算手段は、上記被加熱体と摺接または近接通過して該被加熱体により加熱される物体が上記被加熱体の位置を通過する前に、該被加熱体を設定温度にするために必要な熱量を演算し、上記制御手段は、該演算手段が算出した熱量に基づき、上記物体が上記被加熱体の位置を通過する前に、上記発熱体への電力供給量を調整することを特徴とする。
【００２０】
同請求項７に係るものは、上記目的を達成するために、請求項１ないし５のいずれかの加熱装置において、上記演算手段は、上記被加熱体と摺接または近接通過して該被加熱体により加熱される物体が上記被加熱体の位置を通過した以降における該被加熱体を設定温度にするために必要な熱量を演算し、上記制御手段は、該演算手段が算出した熱量に基づき、上記物体が上記被加熱体の位置を通過した以降に、上記発熱体への電力供給量を調整することを特徴とする。
【００２１】
同請求項８に係るものは、上記目的を達成するために、請求項１ないし５のいずれかの加熱装置において、上記演算手段は、上記被加熱体と摺接または近接通過して該被加熱体により加熱される物体が上記被加熱体の位置を通過した以降における該被加熱体を設定温度にするために必要な熱量を演算し、上記制御手段は、該演算手段が算出した熱量に基づき、上記物体が上記被加熱体の位置を通過する前に、上記発熱体への電力供給量を調整することを特徴とする。
【００２２】
同請求項９に係るものは、上記目的を達成するために、請求項１ないし８のいずれかの加熱装置において、上記制御手段が、動作状態の選択手段を備え、該選択手段が選択する動作状態が、上記被加熱体を設定温度にするための加熱が必要であり、かつ設定温度に達した後の所定時間内に上記物体が上記被加熱体と摺接または近接して通過することが予想される場合と、上記被加熱体を設定温度にするための加熱が必要であり、かつ設定温度に達した後の所定時間内に上記物体が上記被加熱体と摺接または近接して通過することが予想されない場合と、上記被加熱体を設定温度にするための加熱が必要でなく、かつ設定温度に達した後の所定時間内に上記物体が上記被加熱体と摺接または近接して通過することが予想される場合であり、上記選択手段が、上記動作状態から少なくとも一つを選択し、上記演算手段が、上記選択手段の選択結果に基づき熱量を演算することを特徴とする。
【００２３】
同請求項１０に係るものは、上記目的を達成するために、請求項１ないし９のいずれかの加熱装置において、上記制御部は、上記物体が上記被加熱体と摺接または近接して通過する前に供給を開始して終了する場合の電力供給量と、上記物体が上記被加熱体と摺接または近接して通過する直前または通過以降に供給を開始する電力供給量の割合を設定する手段を有することを特徴とする。
【００２４】
本発明の請求項１１に係る定着装置は、上記目的を達成するために、請求項１ないし１０のいずれかの加熱装置において、上記制御部が電力の供給時間を調整する制御を行うことを特徴とする。
【００２５】
同請求項１２に係るものは、上記目的を達成するために、請求項１ないし１１のいずれかの加熱装置において、上記制御手段は、上記蓄電装置から上記発熱体への単位時間あたりの平均供給電力を増加または減少させる制御を行うものであることを特徴とする。
【００２６】
同請求項１３に係るものは、上記目的を達成するために、請求項１ないし１２のいずれかの加熱装置において、商用電源から上記発熱体へ電力供給する手段を有することを特徴とする。
【００２７】
同請求項１４に係るものは、上記目的を達成するために、請求項１３の加熱装置において、上記制御部が、電源供給源選択手段を備え、該電源供給源選択手段が、上記商用電源から上記発熱体へ電力を供給する場合と、上記商用電源及び上記蓄電装置の双方から上記発熱体へ電力を供給する場合のいずれかを選択することを特徴とする。
【００２８】
本発明の請求項１５に係る定着装置は、上記目的を達成するために、請求項１ないし１４のいずれかの加熱装置を備え、上記発熱体により加熱される被加熱体と摺接または近接通過する記録媒体上の画像を加熱することを特徴とする。
【００２９】
同請求項１６に係るものは、上記目的を達成するために、請求項１５の定着装置において、上記演算手段は、上記記録媒体の通紙枚数、光沢、カラーの少なくともいずれかを用いて該記録媒体を設定温度にするために必要な熱量を演算することを特徴とする。
【００３０】
同請求項１７に係るものは、上記目的を達成するために、請求項１５または１６の定着装置において、上記演算手段は、上記記録媒体の温度、環境温度、表面性状の少なくともいずれかを用いて該記録媒体を設定温度にするために必要な熱量を演算することを特徴とする。
【００３１】
本発明の請求項１７に係る画像形成装置は、上記目的を達成するために、請求項１５ないし１７のいずれかの定着装置を備えることを特徴とする。
【００３２】
【発明の実施の形態】
以下本発明の実施の形態を図面を参照して説明する。
図１は本発明に係る加熱装置の一実施形態の構成を示す回路図である。図に示すように、本実施形態の加熱装置１は、加熱部２、主電源装置３、補助電源装置４、メインスイッチ５、充電器６、切替装置７及び制御手段８を有する。
【００３３】
加熱部２は、主電源装置３から供給される電力により発熱する主発熱体２ａと、補助電源装置４から供給される電力により発熱する補助発熱体２ｂを有し、被加熱体Ｘを加熱するようになっている。主電源装置３は、詳細な図示は省略するが、加熱装置１の設置場所において商用電源から電源供給を受けるように、例えばコンセント等に接続する。そして、加熱部２に応じた電圧の調整及び交流と直流の整流等の機能を有するが、周知であるので詳細な図示及び説明は省略する。
【００３４】
補助電源装置４は、充放電可能なキャパシタＣを有する。キャパシタＣとしては、例えば８０Ｆ程度の静電容量を有するキャパシタを使用してもよいが、電気二重層キャパシタと称される２０００Ｆ程度以上の静電容量を有し、数秒から数１０秒の電力供給には十分な容量を備えているものが適する。すなわち電気二重層キャパシタ等のキャパシタは、二次電池とは異なり、化学反応を伴わないために優れた特徴を有するためである。
【００３５】
既に述べたように、二次電池として一般的なニッケル−カドミウム電池を用いた補助電源装置では、急速充電を行っても数時間の時間を有するが、キャパシタを用いた補助電源装置４では数分程度の急速な充電が可能であり、同一時間内で待機状態と加熱状態を繰返した場合、キャパシタを用いた補助電源装置４を使用することにより、加熱立ち上げ時に確実に補助電源装置４から電力を供給することができ、加熱部２を短時間で所定の温度に立ち上げることができる。また、ニッケル−カドミウム電池は充放電の許容繰り返し回数が５００回から１０００回程度であるため、加熱用の補助電源としては寿命が短く、交換の手間やコストが問題となるが、電気二重層キャパシタを用いた補助電源装置４は充放電の許容繰り返し回数が１万回以上であるとともに、充放電の繰り返しによる劣化も少なく、さらに、鉛蓄電池のように液交換や補充なども必要ないため、メンテナンスをほとんど必要とせず、長期間安定して使用することができる。
【００３６】
なお電気二重層キャパシタは、誘電体がなく、個体電極と溶液界面にできるイオンまたは溶媒分子の電荷が集中した電気二重層のイオン吸着層の吸、脱着反応（充、放電）を利用するもので、繰返し充放電に強くて寿命が長く、メンテナンスの必要がなく、環境にやさしく、しかも充放電効率が高い等の優れた特徴を有し、最近では静電容量が数万Ｆ、エネルギー密度が十数Ｗｈ／ｌという大容量のものも開発され、一層の大容量化が図られつつある。
【００３７】
メインスイッチ５は、主電源装置３から主発熱体２ａに供給する電力をオン／オフするものであり、充電器６は、主電源装置３から供給される電力で補助電源装置４のキャパシタＣを充電する。また切替装置７は、補助電源装置４の充電と補助電源装置４からの補助発熱体２ｂに対する電力供給を切りえ替るものである。
【００３８】
制御手段８は、スイッチ９とＣＰＵ１０を有し、予め設定された後述する条件で補助電源装置４から補助発熱体２ｂに供給する電力をオン／オフ等させる制御を行う。ただし、図示の制御手段８の構成は単なる一例であって、種々の構成のものを採用できる。また補助電源装置４に対する制御のための接続形態等も図示の例に限定されない。例えば切替装置７を切り替えてオン／オフ等の制御を行う構成等々種々の形態を採用できる。
【００３９】
上記のように構成した加熱装置１の基本的な動作を説明する。まず待機時には、切替装置７を切り替て補助電源装置４に充電器６を接続し、補助電源装置４のキャパシタＣを充電しておく。この状態で加熱装置１で加熱部２を加熱するときは、メインスイッチ５をオンにして主電源装置３から主発熱体２ａに電力を供給し、同時に切替装置７を切り替て補助電源装置４から補助発熱体２ｂに電力を供給し、加熱部２に大容量の電力を供給する。このように加熱部２の加熱を開始するときに、主電源装置３と補助電源装置４の両方から大容量の電力を加熱部２に供給するから、加熱部２を短時間で所定の温度に立ち上げることができる。
【００４０】
また、補助電源装置４で加熱部２の補助発熱体２ｂに電力を供給して加熱を開始してから予め定めた所定の時間が経過したときに、制御手段８は補助電源装置４から補助発熱体２ｂに供給している電力を遮断して加熱部２の過熱を防止して所定の温度に維持する。補助電源装置４から補助発熱体２ｂに供給する電力は、供給を開始してから時間が経過するにつれて低減する。この供給電力の低減量に応じて、補助電源装置４から補助発熱体２ｂに供給している電力を遮断する時間を定め、供給電力がある程度低減したときに補助電源装置４から補助発熱体２ｂに供給している電力を遮断すると、大電力を供給している状態で遮断するときに発生する周囲回路の各部品の劣化や電磁ノイズを防止することができる。
【００４１】
このように補助電源装置４から補助発熱体２ｂに供給している電力を遮断したとき、補助電源装置４には十分に充電されていない状態となる。そこで加熱部２の温度が安定して比較的電力を消費しないときに、切替装置７を充電器６側に切り替て補助電源装置４に充電器６を接続して主電源装置３から供給される電力で補助電源装置４を充電しておく。そして加熱部２に再度多量の電力を供給する必要があるとき、主電源装置３とともに補助電源装置４から電力を供給して加熱部２に多量のエネルギを供給する。
【００４２】
ところで補助電源装置４から補助発熱体２ｂへの供給電力量を調整する場合、上述のように供給電力を遮断するタイミングによって供給電力量を調整するだけでは、既に述べたように発熱体へ必要な電力量のみ供給するようするには、本実施形態では、制御手段８が以下のように制御する。
【００４３】
基本的には、制御手段８のＣＰＵ１０が、被加熱体Ｘを設定温度にするために必要な熱量を演算する演算手段を構成し、ＣＰＵ１０により演算した熱量に基づき、補助電源装置４から補助発熱体２ｂへの電力供給量を調整する制御を行う。制御手段８は、補助発熱体２ｂにより加熱される被加熱体Ｘの設定温度または被加熱体Ｘに対して設けた温度センサＳによる検知温度に基づいて制御する構成としても良い。被加熱体Ｘの検知温度に基づいて制御する場合は、温度センサＳによる検知温度を、補助電源装置４から補助発熱体２ｂへの電力供給開始時の温度または電力供給開始後に変化した温度のいずれかとすることができる。
【００４４】
またＣＰＵ１０が被加熱体Ｘの設定温度と温度センサＳによる検知温度の対比結果に基づいて必要な熱量を演算し、制御手段８がその演算結果に基づいて制御する構成とすることもできる。ここにおいて対比結果を基準とするとは、温度差そのものを制御基準に用いる場合や、温度差をなくすように制御する等、種々の態様を挙げ得る。
【００４５】
さらにＣＰＵ１０が補助電源装置４のキャパシタＣの保有電力量に基いて必要な熱量を演算し、制御手段８がその演算結果に基づいて制御する構成とすることもできる。キャパシタＣの保有電力量を得るためには、例えば、補助電源装置４の電圧検出値を用いたり、あるいは、充電開始後の経過時間を用いたりすることが可能である。もちろん、補助電源装置４の電圧を検出する手段やタイマー等が必要となる。
【００４６】
またさらにＣＰＵ１０が被加熱体Ｘと摺接または近接通過して被加熱体Ｘにより加熱される物体が被加熱体Ｘの位置を通過する前に、被加熱体Ｘを設定温度にするために必要な熱量を演算し、制御手段８がその演算により算出された熱量に基づいて、物体が被加熱体Ｘの位置を通過する前に補助発熱体２ｂへの電力供給量を調整、制御する構成とすることができる。
【００４７】
あるいはＣＰＵ１０が、被加熱体Ｘにより加熱される物体が被加熱体Ｘの位置を通過した以降における被加熱体Ｘを設定温度にするために必要な熱量を演算し、制御手段８がその演算により算出された熱量に基づいて、物体が被加熱体Ｘの位置を通過した以降に補助発熱体２ｂへの電力供給量を調整、制御する構成とすることができる。
【００４８】
またあるいはＣＰＵ１０が、被加熱体Ｘにより加熱される物体が被加熱体Ｘの位置を通過した以降における被加熱体Ｘを設定温度にするために必要な熱量を予測的に演算し、制御手段８が、その演算により算出された熱量に基づいて、物体が被加熱体Ｘの位置を通過する前に補助発熱体２ｂへの電力供給量を調整、制御する構成とすることもできる。
【００４９】
またさらに制御手段８のＣＰＵ１０が、演算動作の状態を選択する手段を兼ねる構成とし、選択する動作状態が、
（１）被加熱体Ｘを設定温度にするための加熱が必要であり、かつ設定温度に達した後の所定時間内に、被加熱体Ｘにより加熱する対象となる物体が被加熱体Ｘと摺接または近接して通過することが予想される場合、
（２）被加熱体Ｘを設定温度にするための加熱が必要であり、かつ設定温度に達した後の所定時間内に、被加熱体Ｘにより加熱する対象となる物体が被加熱体Ｘと摺接または近接して通過することが予想されない場合、
（３）被加熱体Ｘを設定温度にするための加熱が必要ではなく、かつ設定温度に達した後の所定時間内に、被加熱体Ｘにより加熱する対象となる物体が被加熱体Ｘと摺接または近接して通過することが予想される場合
とし、選択手段としてのＣＰＵ１０が、上記動作状態から一つまたは複数を選択し、その選択結果に基づいて熱量を演算し、制御手段８が、その演算により算出された熱量に基づいて補助発熱体２ｂへの電力供給量を調整、制御する構成とすることもできる。
【００５０】
これらの例の場合、制御手段８がどの時点で補助発熱体２ｂへの電力供給量を調整、制御するかは、物体が被加熱体Ｘの位置を通過する前、以降のいずれかを適宜選択することになる。
【００５１】
また制御手段８のＣＰＵ１０が、物体が被加熱体Ｘと摺接または近接して通過する前に供給を開始して終了する場合の電力供給量と、物体が被加熱体Ｘと摺接または近接して通過する直前または通過以降に供給を開始する電力供給量の割合を設定する手段を兼ねる構成とすることもできる。この場合、電力供給量の割合は予め設定しておくことが好ましい。
【００５２】
さらに、制御手段８が電力の供給時間を調整する制御を行う構成とすることもできる。
【００５３】
また、制御手段８が補助電源装置４から補助発熱体２ｂへの単位時間あたりの平均供給電力を増加または減少させる制御を行う構成とすることもできる。この場合、補助電源装置４から補助発熱体２ｂへの電力供給を開始した後、単位時間あたりの平均供給電力を増加または減少させて、その後に電力供給を停止する。補助電源装置４から補助発熱体２ｂへの電力供給をオン／オフさせるスイッチ９のオン／オフ周期を、例えば図３に示すように変更することにより、単位時間あたりの平均供給電力を増加または減少させてもよい。なお、ここに言う単位時間あたりの平均供給電力を増加または減少させるとは、例えば単位時間を１秒（制御手段８が制御できる範囲であればどのような時間間隔でも良い）とした場合、図２に示す供給電力量を理想的に変化させた場合のように、１秒毎に供給する電力の積算値を変化させることである。もちろん、図２のような変化形態でなくても良い。
【００５４】
制御手段８が単位時間あたりの平均供給電力を増加または減少させる基準としては、既に述べた被加熱体Ｘの設定温度、検知温度を挙げ得る。被加熱体Ｘの検知温度は、これも上述のように、電力供給開始時の温度でも、電力供給開始後逐次変化する温度でもいずれでも良く、被加熱体Ｘの検知温度の変化に基づく場合、その変化を抑制するように、単位時間あたりの平均供給電力を増加または減少させることが装置動作の安定化を図る上で好ましい。またさらに、被加熱体Ｘの設定温度と被加熱体の検知温度の対比結果を基準とすることもできる。
【００５５】
また制御手段８が単位時間あたりの平均供給電力を増加または減少させる異なる基準としては、上述した補助電源装置４のキャパシタＣの保有電力量も採用できる。
【００５６】
なお図示は省略するが、上述したすべての例において、主電源装置３を介して商用電源からも補助発熱体２ｂ、２ｃへ電力供給させ得る構成とし、制御手段８がこの商用電源からの電源供給をも制御できるようにしても良い。
【００５７】
次に、上述してきた本発明の加熱装置１を、例えば電子写真方式の複写機やプリンタ装置等の画像形成装置の定着装置として用い、記録媒体に転写されたトナー像を加熱、加圧して記録媒体に固着させる実施形態について説明する。
【００５８】
図４は、本発明に係る定着装置を採用した電子写真方式の画像形成装置を概念的に示す断面図である。本実施形態の画像形成装置は主に、図示のように、原稿を読み取る読み取りユニット１１、画像を形成する画像形成部１２、自動原稿搬送装置（ＡＤＦ）１３、ＡＤＦ１３から送り出される原稿をスタックする原稿排紙トレイ１４、給紙カセット１５ないし１８を備える給紙部１９、記録用紙をスタックする排紙部（排紙トレイ２０）により構成してある。
【００５９】
そして、ＡＤＦ１３の原稿台２１上に原稿Ｄをセットして図示せぬ操作部での操作、例えばプリントキーの押下操作をすると、最上位の原稿Ｄがピックアップローラ２２の回転により矢印Ｂ１方向へ送り出され、原稿搬送ベルト２３の回転により、画像読み取りユニット１１に固定されたコンタクトガラス２４上へ給送され、そこで停止する。コンタクトガラス２４上に載置された原稿Ｄの画像は、画像形成部１２とコンタクトガラス２４の間に位置する読み取り装置２５によって読み取る。読み取り装置２５は、コンタクトガラス２４上の原稿Ｄを照明する光源２６、原稿画像を結像する光学系２７、原稿画像を結像させるＣＣＤ等からなる光電変換素子２８等を有している。画像読み取り終了後、原稿Ｄを搬送ベルト２３の回転により矢印Ｂ２方向へ搬送して排紙トレイ１４上へ排出する。このように、原稿Ｄを１枚ずつコンタクトガラス１４上へ給送して原稿画像を画像読み取りユニット１によって読み取る。
【００６０】
一方、画像形成部２の内部には、像担持体である感光体３０が配置してある。感光体３０は、図において時計方向に回転駆動し、帯電装置３１によって表面を所定の電位に帯電させる。また、書き込みユニット３２からは、読み取り装置２５によって読み取った画像情報に応じて光変調したレーザ光Ｌを照射し、帯電させた感光体３０の表面をこのレーザ光Ｌで露光し、これによって感光体３０の表面に静電潜像を形成する。この静電潜像は、現像装置３３を通るとき、対向する転写装置３４によって感光体３０と転写装置３４の間に給送された記録媒体Ｐに転写する。トナー像転写後の感光体３０の表面は、クリーニング装置３５によって清掃する。
【００６１】
画像形成部２の下部に配置した複数の給紙カセット１５ないし１８には、紙等の記録媒体Ｐを収容してあり、いずれかの給紙カセット１５ないし１８から記録媒体Ｐを矢印Ｂ３方向へ送り出し、その記録媒体Ｐの表面に、上述のように感光体３０の表面に形成したトナー像を転写する。次に、記録媒体Ｐを矢印Ｂ４で示すように画像形成部２内の定着装置３６を通し、熱と圧力の作用によって記録媒体Ｐの表面に転写されたトナー像を定着させる。定着装置３６を通った記録媒体Ｐを排出ローラ対３７によって搬送し、矢印Ｂ５で示すように排紙トレイ２０へ排出し、スタックする。
【００６２】
図５は、上述のような定着装置の一例を示す断面図である。図示の定着装置３６は、定着ローラ４０と加圧ローラ４１を有し、定着ローラ４０には、例えばハロゲンヒータからなる主発熱体２ａと補助発熱体２ｂからなる本発明の上述した実施形態に係る加熱部２を内蔵し、定着ローラ４０と加圧ローラ４１とで、トナーＴが載った記録媒体Ｐを通過させて加圧、加熱するニップ部Ｎを形成している。図示は省略するが、定着ローラ４０の温度を検知するセンサＳを近傍に設ける。もちろん、定着装置３６の周囲温度、記録媒体Ｐの温度等を検知するように構成しても良い。
【００６３】
この定着装置３６に送られたトナー像Ｔが転写された記録媒体Ｐは、定着ローラ４０と加圧ローラ４１の間に搬送され、一定温度に加熱された定着ローラ４０によりトナーＴを加熱溶融し、記録媒体Ｐにトナー像Ｔを定着させる。そのため定着ローラ４０の加熱部２が有する主発熱体２ａと補助発熱体２ｂには主電源装置３と補助電源装置４から電力を供給し、それにより定着ローラ４０の温度を上昇させ、かつ補助電源装置４から供給する電力をオン／オフ制御することにより、定着ローラ４０の温度が高くなりすぎることを防止して、定着温度を一定温度あるいは所望の温度に保ち、または所要の温度変化を示すように制御することにより、トナーＴを安定して加熱溶融させ、良質なトナー像Ｔを記録媒体Ｐに定着させる。また、定着ローラ４０に内蔵した加熱部２の主発熱体２ａと補助発熱体２ｂに主電源装置３と補助電源装置４から電力を供給して定着ローラ４０の温度を上昇させるので、定着ローラ４０の表面温度を所定の定着温度まで迅速に上昇させることができるようになっている。なお加熱部２として、複数の補助発熱体を含む構成とすることもできる。
【００６４】
このような構成の定着装置において、演算手段であるＣＰＵ１０が記録媒体Ｐを設定温度にするために必要な熱量を演算するために、記録媒体Ｐの通紙枚数、光沢、カラー等の記録媒体Ｐが有する特性を、少なくとも一つを用いることができる。記録媒体Ｐの特性により、必要な熱量が異なるためである。また記録媒体Ｐの温度、定着装置周りの環境温度、画像形成装置の画像形成部２内の環境温度、記録媒体Ｐの凹凸等の表面性状の少なくとも一つを用いることもできる。これらも所要熱量に影響があるためである。
【００６５】
ここで、記録媒体Ｐが定着ローラ４０と加圧ローラ４１のニップ部Ｎを通過して定着ローラ４０により加熱される前に、ＣＰＵ１０が定着ローラ４０を設定温度にするために必要な熱量を演算し、制御手段８がその演算により算出された熱量に基づいて補助発熱体２ｂへの電力供給量を調整、制御する場合は、定着装置としての立ち上げ状態を考慮して記録媒体Ｐが定着ローラ４０の位置を通過する前に定着ローラ４０の温度調整を終了できるので、補助電源装置４から補助発熱体２ｂへ供給される電力量は必要な量にとどめることができる。
【００６６】
また、通過する記録媒体Ｐによって定着ローラ４０が熱を奪われるので、記録媒体Ｐが定着ローラ４０の位置を通過した以降に設定温度にするために必要な熱量を演算し、制御手段８がその演算により算出された熱量に基づいて、記録媒体Ｐの通過以降に補助発熱体２ｂへの電力供給量を調整、制御すれば、これも補助電源装置４から補助発熱体２ｂへ供給される電力量は必要な量にとどめることができる。
【００６７】
さらに、記録媒体Ｐが定着ローラ４０の位置を通過して奪われる熱量を予め考慮しておいて定着ローラ４０を設定温度に戻すために必要な熱量を演算し、制御手段８が、その演算により算出された熱量に基づいて、記録媒体Ｐが定着ローラ４０の位置を通過する前に補助発熱体２ｂへの電力供給量を調整、制御するようにしても、補助電源装置４から補助発熱体２ｂへ供給される電力量は必要な量にとどめることができる。すなわち、記録媒体Ｐの通過後の状態を予想して補助発熱体２ｂへ余分な電力を供給しないようにコントロールできる。
【００６８】
既述のように、制御手段８のＣＰＵ１０の演算動作の状態を選択できるが、上記加熱部２におけるＣＰＵ１０が選択する動作状態（１）ないし（３）は、本例の定着装置の場合、
（１）定着ローラ４０を設定温度にするための加熱が必要であり、かつ設定温度に達した後の所定時間内に、記録媒体Ｐがニップ部Ｎを通過することが予想される場合は、加熱部２による加熱が終了して定着ローラ４０の温度が低下している状態に、
（２）定着ローラ４０を設定温度にするための加熱が必要であり、かつ設定温度に達した後の所定時間内に、記録媒体Ｐがニップ部Ｎを通過することが予想されない場合は、定着装置が立ち上がり、その後に加熱が終了し、それからすぐには定着動作を行わない状態に、
（３）定着ローラ４０を設定温度にするための加熱が必要ではなく、かつ設定温度に達した後の所定時間内に、記録媒体Ｐがニップ部Ｎを通過することが予想されない場合は、加熱部２による加熱が終了して定着ローラ４０の温度が低下してはいるが、補助発熱体２ｂを利用して再昇温する必要はなく、状況に応じて温度低下分だけ定着ローラ４０を加熱すればよいという状態に、
それぞれ、対応している。この３つの状態を想定して定着ローラ４０の温度を調整、制御すれば、ほとんどの状態を考慮に入れた制御を行えるので、余分な電力供給をなくせる。
【００６９】
このような構成の定着装置において、補助電源装置４から補助発熱体２ｂへの電力供給を開始した後、単位時間あたりの平均供給電力を増加または減少させて、その後に電力供給を停止するという上述のような制御手段８による制御を行う場合、上述した制御例のいずれの場合でも、ニップ部Ｎを記録媒体Ｐが通過する前に行うようにすることができる。ニップ部Ｎを記録媒体Ｐが通過する前の時点で加熱部２による定着ローラ４０の加熱が完了していること考慮したものである。
【００７０】
もちろん、ニップ部Ｎを記録媒体Ｐが通過する直前または通過が開始されてから上述のような単位時間あたりの平均供給電力の制御を行っても良い。記録媒体Ｐが定着ローラ４０と接触または近接することによって定着ローラ４０から熱を奪い、定着ローラ４０の温度が低下することが明らかであるためで、いっそう緻密な制御が可能であり、各構成要素の応答性が高ければ、よりいっそう緻密に制御できる。
【００７１】
このような定着装置において、定着温度、すなわち定着ローラ４０の温度あるいは補助電源装置４のキャパシタＣの保有電力量またはこれらを両方とも、制御手段８が単位時間あたりの平均供給電力を増加または減少させる基準として採用することにより、上述した本発明の加熱装置の実施形態と同様に、いっそう供給電力量を緻密に調整することができる。
【００７２】
すなわち、図２に示すように補助電源装置４から補助発熱体２ｂへの単位時間あたりの平均供給電力を増加または減少させる制御、補助電源装置４から補助発熱体２ｂへの電力供給をオン／オフさせるスイッチ９のオン／オフ周期を変更することによって単位時間あたりの平均供給電力を増加または減少させる制御が可能であり、制御手段８が単位時間あたりの平均供給電力を増加または減少させる基準としては、補助発熱体２ｂにより加熱する被加熱体である定着ローラ４０の設定温度や検知温度を採用できる。定着ローラ４０の検知温度は、電力供給開始時の温度でも、電力供給開始後逐次変化する温度でもいずれでも良く、定着ローラ４０の検知温度変化に基づく場合は変化を抑制するように、単位時間あたりの平均供給電力を増加または減少させて定着動作の安定化を図る制御を採用できる。またさらに、定着ローラ４０の設定温度と検知温度の対比結果を基準とすることもできる。対比結果を基準とする場合に、定着ローラ４０の設定温度と検知温度の温度差そのものを制御基準に用いることや、温度差をなくすように制御すること等、種々の態様を取り得る。図示は省略するが、これらの例においては、定着ローラ４０の温度を検知するセンサ等の手段を必要とし、制御手段８のＣＰＵ１０は検出した温度値を演算処理する機能が必要である。
【００７３】
また同様に、制御手段８が単位時間あたりの平均供給電力を増加または減少させる異なる基準としては、補助電源装置４のキャパシタＣの保有電力量を採用できる。この場合、図示せぬが補助電源装置４の電圧を検出する手段やタイマー等が必要となり、補助電源装置４の電圧検出値を用いたり、充電開始後の経過時間を用いたりすることが可能である。
【００７４】
さらに、加熱部２が、第１の補助発熱体２ｂに加え、これと定格消費電力が異なる第２の補助発熱体を含み、制御手段８が複数の補助発熱体を適時に切り替えることによって、単位時間あたりの平均供給電力を増加または減少させるようにした構成も採用できる。補助発熱体の個数は２個に限定されず、また上述した電力供給量の制御方法を組み合わせて採用することも可能である。そして、補助電源装置４のキャパシタＣの保有電力量を基準とする場合、制御手段８が、補助電源装置４のキャパシタＣの保有電力量が基準電力量以下になった場合に定格消費電力が小さいほうまたは大きいほうの補助発熱体へ切り替える制御を採用でき、これに上述のような各種制御方法を組み合わせることにより、よりいっそう緻密に電力量を調整できる。
【００７５】
また主電源装置３を介して商用電源からも補助発熱体２ｂへ電力供給させ得る構成とし、制御手段８がこの商用電源からの電源供給をも制御できるようにしても良いことも同様である。
【００７６】
なお図示の例では、二つのローラ、すなわち定着ローラ４０と加圧ローラ４１によってニップ部Ｎを形成しているが、本発明の定着装置及びこれを用いた画像形成装置は、このような構成に限定されず、ローラとベルト、ベルトとベルトによりニップ部Ｎを形成するもの等、記録媒体Ｐが被加熱体と摺接または近接して通過するタイプのものであれば採用可能である。また、本発明が図示のタイプの画像形成装置に限定されるものではなく、例えば感光体がドラム状ではなくベルトタイプのもの、中間転写ベルトを用いるカラー画像形成装置等々の種々のタイプの装置に適用可能である。
【００７７】
【発明の効果】
本発明に係る加熱装置、これを用いた定着装置及びこの定着装置を用いた画像形成装置は以上説明してきたように、被加熱体を設定温度にするために必要な熱量を演算し、この演算した熱量に基づいて蓄電装置から発熱体への電力供給量を調整する制御を行うので、蓄電装置から発熱体への電力供給を必要な電力量のみあるいは必要な電力量に近い量だけ行えるようになるという効果がある。
【図面の簡単な説明】
【図１】本発明に係る加熱装置の一実施形態の構成を示す回路図である。
【図２】本発明の実施形態における、単位時間あたりの平均供給電力を増加または減少させる例を示す図である。
【図３】本発明の実施形態における、単位時間あたりの平均供給電力を増加または減少させる他の例を示す図である。
【図４】本発明に係る画像形成装置の実施形態を示す概念的断面図である。
【図５】図４の画像形成装置に用いる本発明の実施形態に係る定着装置の構成を示す概念的断面図である。
【符号の説明】
１加熱装置
２加熱部
２ａ主発熱体
２ｂ補助発熱体
３主電源装置
４補助電源装置
５メインスイッチ
６充電器
７切替装置
８制御手段
９スイッチ
１０ＣＰＵ
１１読み取りユニット
１２画像形成部
１３自動原稿搬送装置（ＡＤＦ）
１４原稿排紙トレイ
１５、１６、１７、１８給紙カセット
１９給紙部
２０排紙トレイ
２１原稿台
２５読み取り装置
３０感光体
３１帯電装置
３２書き込みユニット
３３現像装置
３４転写装置
３５クリーニング装置
３６定着装置
３７排出ローラ対
４０定着ローラ
４１加圧ローラ
Ｃキャパシタ
Ｄ原稿
Ｐ記録媒体
Ｔトナー
Ｎニップ部
Ｓセンサ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to, for example, a heating device for heating various materials and devices, a fixing device using the same, and an image forming apparatus such as an electrophotographic copying machine, a printer, and a facsimile using the fixing device. The present invention relates to a device that achieves power saving efficiency.
[0002]
[Prior art]
2. Description of the Related Art In an image forming apparatus such as a copying machine, an image is formed on a recording medium such as plain paper or OHP, and an electrophotographic method is often used because of high speed of image formation, image quality, cost, and the like. The electrophotographic method is a method in which a toner image is formed on a recording medium, and the formed toner image is fixed on the recording medium by heat and pressure. As a fixing method, a heat roller method is currently most frequently employed in terms of safety and the like. In the heat roller method, a heating roller heated by a heating member such as a halogen heater and a pressure roller arranged opposite to the heating roller are pressed to form a mutual press contact portion called a nip portion, and a toner image is formed in the nip portion. Is heated and pressed through the recording medium onto which the toner has been transferred, thereby fixing the toner to the recording medium.
[0003]
2. Description of the Related Art In recent years, environmental issues have become important, and image forming apparatuses such as copiers and printers have been saving energy. In considering the energy saving of the image forming apparatus, what cannot be ignored is the power saving of the fixing device that fixes the toner on the recording medium. Therefore, in order to reduce the power consumption of the fixing device during the standby time of the image forming apparatus, the temperature of the heating roller is maintained at a fixed temperature slightly lower than the fixing temperature during the standby time, and the temperature is immediately raised to the usable temperature at the time of use, and the use temperature is increased. In many cases, a method is employed in which a user does not wait for the temperature of the fixing roller to rise. In this method, a certain amount of power must be supplied even when the fixing device is not used, thereby consuming extra energy. It is said that the energy consumption during the standby corresponds to about 70% to 80% of the energy consumption of the devices constituting the image forming apparatus.
[0004]
Therefore, it has been desired to reduce energy consumption during standby and to further reduce power consumption, and it is required to reduce power supply to zero when not in use. However, if the energy consumption is reduced to zero during standby, the heating roller of the fixing device mainly uses a metal roller such as iron or aluminum and has a large heat capacity, so that the temperature rises to a usable temperature of about 180 ° C. Requires a long heating time of several minutes to several tens of minutes. Such a waiting time deteriorates the usability of the user. Therefore, a heating method that consumes as little power as possible and that quickly rises from the standby state is desired.
[0005]
It is clear that it is better to increase the input energy per unit time, that is, the rated power, in order to shorten the heating time of the heating roller. Actually, an image forming apparatus called a high-speed machine having a high print speed is required. In many cases, the power supply voltage is set to 200 V to cope with the problem. However, in a general office in Japan, the commercial power supply is 100V and 15A, and it is necessary to perform special work on the power supply related equipment at the installation place to support 200V. This is not a practical solution.
[0006]
That is, as long as a commercial power supply of 100 V and 15 A is used, even if an attempt is made to raise the temperature of the heating roller in a short period of time, the maximum input energy is determined by the power supply. When the temperature of the fixing device becomes low, the temperature of the fixing device is reduced by supplying a voltage lower by a certain level to the heating roller (for example, see Patent Document 1). When the fixing device is started up, power is supplied from a main power supply device and a secondary battery or a primary battery to shorten the start-up time (for example, see Patent Document 2).
[0007]
However, the technique disclosed in Patent Document 1 does not provide sufficient power saving because a low voltage is supplied to the fixing device by a certain level even during standby. Further, it is not intended to mainly increase the maximum supply power at the time of startup than the power supplied from the main power supply device. On the other hand, the fixing device disclosed in Patent Literature 2 supplies power from a main power supply device and a secondary battery or a primary battery at the time of start-up. As a secondary power source, a lead storage battery, a nickel-cadmium battery, and a nickel hydrogen battery are generally used. I'm using Such a secondary battery has the property that the capacity deteriorates and decreases when charge and discharge are repeated, and the life is shortened as the discharge is performed with a large current. There is also a phenomenon that the capacity is reduced by the memory effect. Even though a battery is generally considered to have a long life at a large current, the number of charge / discharge repetitions is about 500 to 1000 times, and if the charge / discharge is repeated 20 times a day, the battery life can be reduced to about one month. Will be. Therefore, the replacement frequency of the battery is increased, which is troublesome, and the running cost such as the cost of replacing the battery is increased. Furthermore, lead-acid batteries use liquid sulfuric acid as an electrolyte, which is not desirable for office equipment.
[0008]
In addition, the load on the heating circuit built into the heating roller increases due to sudden current changes and rush power when starting or stopping the supply of large power, and the input current also increases in the peripheral circuits. There is also a problem that noise occurs due to the flow. For this reason, it is not preferable to frequently turn on and off the power supply from the large-capacity auxiliary power supply. Further, if a large amount of electric power is supplied at one time, the supply becomes excessive, and the temperature of the heating circuit may be too high.
[0009]
In order to improve such a point and improve the power saving effect, reduce the rush current and the noise due to the rapid current change when supplying large power, shorten the rise time, and prevent the temperature from rising too much. The fixing device can use a chargeable / dischargeable capacitor for the auxiliary power supply, the charger charges the capacitor of the auxiliary power supply with electric power supplied from the main power supply, and the switching device charges and charges the auxiliary power supply. There has been proposed a device that switches the power supply from an auxiliary power supply to an auxiliary heating element and adjusts the amount of power supplied from the auxiliary power supply to the auxiliary heating element (for example, see Patent Document 3).
[0010]
The device disclosed in Patent Document 3 has a main heater that generates heat by electric power supplied from a commercial power supply, and an auxiliary heater that generates heat by electric power supplied from an auxiliary power supply device using a capacitor, and is an object to be heated. The heating roller of the fixing device can be heated. For the auxiliary power supply device, a chargeable / dischargeable electric double layer capacitor (or capacitor) having a capacitance of about 2000F and a sufficient capacity for supplying power for several seconds to several tens of seconds is used. The power supplied from the auxiliary power supply to the auxiliary heating element is turned on and off at the timing of shutting off the supplied power, for example, to adjust the amount of supplied power.
[0011]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 10-10913 [Patent Document 2]
JP-A-10-282821 [Patent Document 3]
JP 2002-184554 A
[Problems to be solved by the invention]
By the way, the basic function of the capacitor is to cause the auxiliary heater to generate heat by the power supplied from the capacitor, to use this heat to shorten the time required for the heating roller to rise to a predetermined temperature, and to prevent the fixing temperature from dropping during paper passing. However, it is desirable to supply only a necessary amount of power from the power storage device to the heating element, and the amount of supplied power is adjusted according to the timing of shutting off the supplied power as in the technique disclosed in Patent Document 3. It cannot be realized just by doing.
[0013]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a heating device capable of solving the above-mentioned conventional problems, a fixing device using the same, and an image forming apparatus using the fixing device.
[0014]
[Means for Solving the Problems]
The heating device according to claim 1 of the present invention includes a heating unit, a power storage device for supplying power to the heating unit to heat the heating unit, and an operation of the power storage device. A heating device having a control unit for controlling, the heating unit has a heating element that generates heat by electric power supplied from the power storage device, and the heating device includes a capacitor capable of charging and discharging the power storage device. An operation means for calculating an amount of heat required to bring the object to be heated to a set temperature; and a control for adjusting an amount of electric power supplied from the power storage device to the heating element based on the amount of heat calculated by the operation means. Characterized in that:
[0015]
According to a second aspect of the present invention, in order to achieve the above object, in the heating apparatus according to the first aspect, the control means detects a set temperature of the object to be heated by the heating element or detection of the object to be heated. The control is performed based on the temperature.
[0016]
According to a third aspect of the present invention, in order to achieve the above object, in the heating device according to the second aspect, when controlling based on a detected temperature of the object to be heated, the detected temperature is set to a temperature at the start of power supply. Alternatively, any one of the temperatures changed after the start of power supply is set.
[0017]
According to a fourth aspect of the present invention, in order to achieve the above object, in the heating apparatus according to the second or third aspect, the control means compares a set temperature of the heated object with a detected temperature of the heated object. The control is based on
[0018]
According to a fifth aspect of the present invention, in order to achieve the above object, in the heating device of the first aspect, the control means controls the power storage device in accordance with the amount of stored power. .
[0019]
According to a sixth aspect of the present invention, in order to achieve the above object, in the heating apparatus according to any one of the first to fifth aspects, the arithmetic unit is slidably in contact with or close to the object to be heated. Before the object to be heated by the body passes through the position of the object to be heated, a calorie necessary for setting the body to be heated to a set temperature is calculated, and the control unit calculates the amount of heat calculated by the calculating unit. The power supply to the heating element is adjusted before the object passes through the position of the object to be heated.
[0020]
According to a seventh aspect of the present invention, in order to achieve the above object, in the heating apparatus according to any one of the first to fifth aspects, the arithmetic unit is slidably in contact with or close to the object to be heated. After the object to be heated by the body has passed the position of the object to be heated, the amount of heat required to set the object to be heated to the set temperature is calculated, and the control unit calculates the amount of heat based on the amount of heat calculated by the operation unit. After the object has passed the position of the object to be heated, the amount of power supplied to the heating element is adjusted.
[0021]
According to an eighth aspect of the present invention, in order to achieve the above object, in the heating apparatus according to any one of the first to fifth aspects, the arithmetic unit is slidably in contact with or close to the object to be heated. After the object to be heated by the body has passed the position of the object to be heated, the amount of heat required to set the object to be heated to the set temperature is calculated, and the control unit calculates the amount of heat based on the amount of heat calculated by the operation unit. The power supply to the heating element is adjusted before the object passes through the position of the object to be heated.
[0022]
According to a ninth aspect of the present invention, in order to achieve the above object, in the heating apparatus according to any one of the first to eighth aspects, the control means includes an operation state selection means, and the operation selected by the selection means is selected. The state requires that the object to be heated be heated to a set temperature, and that the object slides on or passes close to the object to be heated within a predetermined time after reaching the set temperature. As expected, the object to be heated needs to be heated to a set temperature, and the object slides in contact with or close to the object to be heated within a predetermined time after reaching the set temperature. When it is not anticipated that the object to be heated does not need to be heated to the set temperature, and the object slides into or comes into contact with the object within a predetermined time after the set temperature is reached. Is expected to pass through -Option means selects at least one from the operating state, said computing means, characterized by calculating the amount of heat based on the selection result of the selecting means.
[0023]
According to a tenth aspect of the present invention, in order to achieve the above object, in the heating device according to any one of the first to ninth aspects, the control unit is configured to allow the object to slidably contact with or pass close to the object to be heated. And the ratio of the power supply amount when the supply starts and ends before the supply, and the power supply amount that starts supply immediately before or after the object slides on or comes close to the object to be heated or after the passage. It is characterized by having means.
[0024]
In order to achieve the above object, a fixing device according to claim 11 of the present invention is the heating device according to any one of claims 1 to 10, wherein the control unit performs control for adjusting a power supply time. And
[0025]
According to a twelfth aspect of the present invention, in order to achieve the above object, in the heating apparatus according to any one of the first to eleventh aspects, the control means controls an average supply per unit time from the power storage device to the heating element. It is characterized by performing control to increase or decrease the power.
[0026]
According to a thirteenth aspect of the present invention, in order to achieve the above object, the heating device according to any one of the first to twelfth aspects has a means for supplying power from a commercial power supply to the heating element.
[0027]
According to a fourteenth aspect, in order to achieve the above object, in the heating apparatus according to the thirteenth aspect, the control unit includes a power supply source selection unit, and the power supply source selection unit is configured to switch the power supply source from the commercial power supply. It is characterized in that one of a case where power is supplied to the heating element and a case where power is supplied to the heating element from both the commercial power supply and the power storage device are selected.
[0028]
In order to achieve the above object, a fixing device according to a fifteenth aspect of the present invention includes the heating device according to any one of the first to fourteenth aspects, wherein the fixing device is in sliding contact with or near a heated object to be heated by the heating element. The method is characterized in that an image on a recording medium to be heated is heated.
[0029]
According to a sixteenth aspect, in order to achieve the above object, in the fixing device according to the fifteenth aspect, the calculating means performs the recording by using at least one of the number of sheets passed through the recording medium, gloss, and color. It is characterized in that the amount of heat required to bring the medium to the set temperature is calculated.
[0030]
According to a seventeenth aspect, in order to achieve the above object, in the fixing device according to the fifteenth or sixteenth aspect, the calculating means uses at least one of a temperature, an environmental temperature, and a surface property of the recording medium. The amount of heat required to bring the recording medium to the set temperature is calculated.
[0031]
An image forming apparatus according to a seventeenth aspect of the present invention includes the fixing device according to any one of the fifteenth to seventeenth aspects to achieve the above object.
[0032]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit diagram showing a configuration of one embodiment of a heating device according to the present invention. As shown in the drawing, the heating device 1 of the present embodiment includes a heating unit 2, a main power supply device 3, an auxiliary power supply device 4, a main switch 5, a charger 6, a switching device 7, and a control unit 8.
[0033]
The heating unit 2 has a main heating element 2 a that generates heat by electric power supplied from the main power supply device 3 and an auxiliary heating element 2 b that generates heat by electric power supplied from the auxiliary power supply device 4, and heats the object to be heated X. It has become. Although not shown in detail, the main power supply device 3 is connected to, for example, an outlet or the like so as to receive power supply from a commercial power supply at a place where the heating device 1 is installed. Further, it has functions such as voltage adjustment according to the heating unit 2 and rectification of AC and DC, but detailed illustration and explanation are omitted because they are well known.
[0034]
The auxiliary power supply 4 has a chargeable / dischargeable capacitor C. As the capacitor C, for example, a capacitor having a capacitance of about 80F may be used. However, the capacitor C has a capacitance of about 2000F or more called an electric double layer capacitor, and supplies electric power for several seconds to several tens of seconds. Those having sufficient capacity are suitable. That is, unlike a secondary battery, a capacitor such as an electric double layer capacitor has excellent characteristics because it does not involve a chemical reaction.
[0035]
As described above, an auxiliary power supply using a general nickel-cadmium battery as a secondary battery has several hours even when quick charging is performed, but an auxiliary power supply 4 using a capacitor has several minutes. When the standby state and the heating state are repeated within the same time, the auxiliary power supply device 4 using a capacitor can be used to ensure that the power is reliably supplied from the auxiliary power supply device 4 when heating is started. And the heating unit 2 can be raised to a predetermined temperature in a short time. In addition, the nickel-cadmium battery has an allowable repetition number of charge / discharge of about 500 to 1000 times, and therefore has a short life as an auxiliary power supply for heating, and has a problem of replacement labor and cost. The auxiliary power supply device 4 using a battery has an allowable number of repetitions of charge / discharge of 10,000 or more, has little deterioration due to repetition of charge / discharge, and does not require liquid exchange or replenishment like a lead-acid battery. And can be used stably for a long period of time.
[0036]
The electric double layer capacitor has no dielectric substance and utilizes the absorption and desorption reactions (charge and discharge) of the ion adsorption layer of the electric double layer in which charges of ions or solvent molecules formed at the interface between the solid electrode and the solution are concentrated. It has excellent features such as high resistance to repeated charge and discharge, long life, no maintenance, environmental friendliness, and high charge / discharge efficiency. A large capacity of several Wh / l has also been developed, and the capacity is being further increased.
[0037]
The main switch 5 turns on / off the power supplied from the main power supply 3 to the main heating element 2 a. The charger 6 controls the capacitor C of the auxiliary power supply 4 with the power supplied from the main power supply 3. Charge. The switching device 7 switches between charging of the auxiliary power supply device 4 and power supply from the auxiliary power supply device 4 to the auxiliary heating element 2b.
[0038]
The control means 8 has a switch 9 and a CPU 10, and performs control such as turning on / off the power supplied from the auxiliary power supply device 4 to the auxiliary heating element 2b under predetermined conditions described later. However, the configuration of the control means 8 shown is merely an example, and various configurations can be adopted. Further, the connection form for controlling the auxiliary power supply device 4 is not limited to the illustrated example. For example, various modes such as a configuration in which the switching device 7 is switched to perform control such as on / off can be adopted.
[0039]
The basic operation of the heating device 1 configured as described above will be described. First, at the time of standby, the switching device 7 is switched, the charger 6 is connected to the auxiliary power supply device 4, and the capacitor C of the auxiliary power supply device 4 is charged. When the heating unit 2 is heated by the heating device 1 in this state, the main switch 5 is turned on to supply power from the main power supply 3 to the main heating element 2a, and at the same time, the switching device 7 is switched to switch from the auxiliary power supply 4 Power is supplied to the auxiliary heating element 2b, and large-capacity power is supplied to the heating unit 2. As described above, when the heating of the heating unit 2 is started, a large amount of electric power is supplied to the heating unit 2 from both the main power supply device 3 and the auxiliary power supply device 4, so that the heating unit 2 is heated to a predetermined temperature in a short time. Can be launched.
[0040]
When a predetermined period of time has elapsed after the auxiliary power supply 4 supplies power to the auxiliary heating element 2 b of the heating unit 2 and starts heating, the control unit 8 outputs the auxiliary heat from the auxiliary power supply 4. The power supplied to the body 2b is cut off to prevent overheating of the heating unit 2 and to maintain a predetermined temperature. The power supplied from the auxiliary power supply device 4 to the auxiliary heating element 2b decreases as time elapses from the start of the supply. In accordance with the amount of reduction in the supplied power, a time period during which the power supplied from the auxiliary power supply 4 to the auxiliary heating element 2b is cut off is determined. When the supplied power is cut off, it is possible to prevent deterioration of each component of the peripheral circuit and electromagnetic noise that occur when the power is cut off while the large power is being supplied.
[0041]
When the power supplied from the auxiliary power supply 4 to the auxiliary heating element 2b is cut off, the auxiliary power supply 4 is not fully charged. Therefore, when the temperature of the heating unit 2 is stable and relatively little power is consumed, the switching device 7 is switched to the charger 6 side, the charger 6 is connected to the auxiliary power device 4 and supplied from the main power device 3. The auxiliary power supply 4 is charged with electric power. When a large amount of electric power needs to be supplied to the heating unit 2 again, electric power is supplied from the auxiliary power supply unit 4 together with the main power supply unit 3 to supply a large amount of energy to the heating unit 2.
[0042]
When the amount of power supplied from the auxiliary power supply device 4 to the auxiliary heating element 2b is adjusted, simply adjusting the amount of power supplied at the timing of shutting off the supply power as described above requires the heating element as described above. In order to supply only the electric energy, in the present embodiment, the control means 8 controls as follows.
[0043]
Basically, the CPU 10 of the control means 8 constitutes an arithmetic means for calculating the amount of heat necessary to bring the object X to the set temperature, and the auxiliary power supply 4 generates the auxiliary heat based on the amount of heat calculated by the CPU 10. Control for adjusting the amount of power supply to the body 2b is performed. The control means 8 may be configured to perform control based on a set temperature of the object X to be heated by the auxiliary heating element 2b or a temperature detected by a temperature sensor S provided for the object X to be heated. When the control is performed based on the detected temperature of the object to be heated X, the temperature detected by the temperature sensor S is set to either the temperature at the time of starting the power supply from the auxiliary power supply device 4 to the auxiliary heating element 2b or the temperature that has changed after the start of the power supply. Or can be.
[0044]
Alternatively, the CPU 10 may calculate a required amount of heat based on a result of comparison between the set temperature of the object to be heated X and the temperature detected by the temperature sensor S, and the control unit 8 may control the temperature based on the result of the calculation. Here, the term “based on the comparison result” refers to various modes such as a case where the temperature difference itself is used as a control reference and a case where control is performed so as to eliminate the temperature difference.
[0045]
Further, the CPU 10 may calculate a necessary amount of heat based on the amount of electric power held by the capacitor C of the auxiliary power supply device 4, and the control unit 8 may control based on the calculation result. In order to obtain the stored electric energy of the capacitor C, for example, it is possible to use the detected voltage value of the auxiliary power supply device 4 or to use the elapsed time after the start of charging. Needless to say, means for detecting the voltage of the auxiliary power supply 4 and a timer are required.
[0046]
Further, it is necessary for the CPU 10 to bring the object to be heated X into the set temperature before the object to be heated by the object to be heated X by sliding or approaching the object to be heated X passes through the position of the object to be heated X. And the control means 8 adjusts and controls the amount of power supply to the auxiliary heating element 2b before the object passes through the position of the object to be heated X, based on the amount of heat calculated by the calculation. can do.
[0047]
Alternatively, the CPU 10 calculates the amount of heat required to bring the object X to a set temperature after the object heated by the object X has passed the position of the object X, and the control means 8 calculates Based on the calculated amount of heat, the amount of power supply to the auxiliary heating element 2b can be adjusted and controlled after the object has passed the position of the object to be heated X.
[0048]
Alternatively, the CPU 10 predictively calculates the amount of heat required to bring the object to be heated X to the set temperature after the object to be heated by the object to be heated X passes the position of the object to be heated X. However, it is also possible to adopt a configuration in which the amount of electric power supplied to the auxiliary heating element 2b is adjusted and controlled before the object passes through the position of the object X to be heated, based on the amount of heat calculated by the calculation.
[0049]
Further, the CPU 10 of the control means 8 is configured to also serve as a means for selecting a state of the arithmetic operation, and the operation state to be selected is:
(1) The object to be heated by the object to be heated X needs to be heated by the object to be heated X within a predetermined time after reaching the set temperature. If you are expected to slide or approach,
(2) It is necessary to heat the object to be heated X to the set temperature, and the object to be heated by the object to be heated X is within a predetermined time after reaching the set temperature. If you are not expected to slide or approach,
(3) It is not necessary to heat the object to be heated X to the set temperature, and the object to be heated by the object to be heated X is within a predetermined time after reaching the set temperature. Assume that it is expected that the vehicle will pass by sliding or close proximity, and the CPU 10 as a selecting means selects one or more from the above operating states, calculates a heat quantity based on the selection result, and The power supply amount to the auxiliary heating element 2b may be adjusted and controlled based on the heat amount calculated by the calculation.
[0050]
In the case of these examples, the time at which the control means 8 adjusts and controls the amount of power supply to the auxiliary heating element 2b is selected as appropriate before or after the object passes through the position of the object X to be heated. Will do.
[0051]
Further, the CPU 10 of the control means 8 determines the power supply amount when the supply starts and ends before the object passes through the object to be heated X in sliding contact with or close to the object to be heated X. It is also possible to adopt a configuration that also serves as a means for setting the ratio of the amount of power supply to start supplying immediately before or after passing. In this case, the ratio of the power supply amount is preferably set in advance.
[0052]
Further, the control unit 8 may be configured to perform control for adjusting the power supply time.
[0053]
Further, the control means 8 may be configured to perform control for increasing or decreasing the average supply power per unit time from the auxiliary power supply device 4 to the auxiliary heating element 2b. In this case, after starting the power supply from the auxiliary power supply device 4 to the auxiliary heating element 2b, the average supply power per unit time is increased or decreased, and then the power supply is stopped. By changing the on / off cycle of the switch 9 for turning on / off the power supply from the auxiliary power supply device 4 to the auxiliary heating element 2b, for example, as shown in FIG. 3, the average supply power per unit time is increased or decreased. You may let it. Here, increasing or decreasing the average supply power per unit time means, for example, that the unit time is 1 second (any time interval is acceptable as long as it can be controlled by the control means 8). As in the case where the supplied power amount shown in FIG. 2 is ideally changed, the integrated value of the supplied power is changed every second. Of course, it is not necessary to have the variation as shown in FIG.
[0054]
As a criterion for the control means 8 to increase or decrease the average supply power per unit time, the set temperature and the detected temperature of the object to be heated X described above can be mentioned. As described above, the detected temperature of the object to be heated X may be either the temperature at the time of starting the power supply or the temperature that sequentially changes after the start of the power supply. It is preferable to increase or decrease the average supply power per unit time so as to suppress the change in order to stabilize the operation of the apparatus. Further, a comparison result between the set temperature of the object to be heated X and the detected temperature of the object to be heated can be used as a reference.
[0055]
Further, as a different criterion for the control means 8 to increase or decrease the average supply power per unit time, the above-mentioned retained power amount of the capacitor C of the auxiliary power supply device 4 can be adopted.
[0056]
Although not shown, in all of the above-described examples, the configuration is such that power can also be supplied from the commercial power supply to the auxiliary heating elements 2b and 2c via the main power supply device 3, and the control means 8 supplies power from the commercial power supply. May also be controlled.
[0057]
Next, the above-described heating device 1 of the present invention is used as a fixing device of an image forming apparatus such as an electrophotographic copying machine or a printer, and the toner image transferred to the recording medium is heated and pressed to be recorded. An embodiment in which the recording medium is fixed to a medium will be described.
[0058]
FIG. 4 is a sectional view conceptually showing an electrophotographic image forming apparatus employing the fixing device according to the present invention. The image forming apparatus according to the present embodiment mainly includes a reading unit 11 for reading a document, an image forming unit 12 for forming an image, an automatic document feeder (ADF) 13, and a document for stacking documents sent from the ADF 13, as illustrated. It comprises a paper discharge tray 14, a paper supply unit 19 having paper supply cassettes 15 to 18, and a paper discharge unit (paper discharge tray 20) for stacking recording paper.
[0059]
When the document D is set on the document table 21 of the ADF 13 and an operation is performed on an operation unit (not shown), for example, a print key is pressed, the uppermost document D is sent out in the direction of arrow B1 by the rotation of the pickup roller 22. Then, the document is conveyed onto the contact glass 24 fixed to the image reading unit 11 by the rotation of the document conveying belt 23, and stops there. The image of the document D placed on the contact glass 24 is read by a reading device 25 located between the image forming unit 12 and the contact glass 24. The reading device 25 has a light source 26 for illuminating the document D on the contact glass 24, an optical system 27 for forming a document image, a photoelectric conversion element 28 such as a CCD for forming a document image, and the like. After the image reading is completed, the document D is conveyed in the direction of arrow B <b> 2 by the rotation of the conveyance belt 23 and is discharged onto the discharge tray 14. In this way, the document D is fed one by one onto the contact glass 14 and the document image is read by the image reading unit 1.
[0060]
On the other hand, a photoreceptor 30 as an image carrier is disposed inside the image forming section 2. The photoreceptor 30 is rotated clockwise in the drawing, and the surface is charged to a predetermined potential by the charging device 31. Further, the writing unit 32 irradiates a laser beam L light-modulated in accordance with image information read by the reading device 25, and exposes the surface of the charged photoconductor 30 with the laser beam L. An electrostatic latent image is formed on the surface of the substrate 30. When the electrostatic latent image passes through the developing device 33, the electrostatic latent image is transferred to the recording medium P fed between the photoconductor 30 and the transfer device 34 by the transfer device 34 opposed thereto. The surface of the photoconductor 30 after the transfer of the toner image is cleaned by the cleaning device 35.
[0061]
A plurality of paper cassettes 15 to 18 disposed below the image forming unit 2 accommodate recording media P such as paper, and the recording media P is fed from any of the paper cassettes 15 to 18 in the direction of arrow B3. The toner image formed on the surface of the photoconductor 30 is transferred to the surface of the recording medium P as described above. Next, the recording medium P is passed through a fixing device 36 in the image forming unit 2 as indicated by an arrow B4, and the toner image transferred to the surface of the recording medium P by the action of heat and pressure is fixed. The recording medium P that has passed through the fixing device 36 is conveyed by the discharge roller pair 37, discharged to the discharge tray 20 as indicated by an arrow B5, and stacked.
[0062]
FIG. 5 is a cross-sectional view illustrating an example of the above-described fixing device. The illustrated fixing device 36 includes a fixing roller 40 and a pressure roller 41, and the fixing roller 40 includes the main heating element 2a including a halogen heater and the auxiliary heating element 2b according to the above-described embodiment of the present invention. The heating unit 2 is built in, and a fixing roller 40 and a pressure roller 41 form a nip portion N for applying pressure and heating by passing the recording medium P on which the toner T is loaded. Although not shown, a sensor S for detecting the temperature of the fixing roller 40 is provided in the vicinity. Of course, it may be configured to detect the ambient temperature of the fixing device 36, the temperature of the recording medium P, and the like.
[0063]
The recording medium P on which the toner image T transferred to the fixing device 36 is transferred is conveyed between the fixing roller 40 and the pressure roller 41, and the toner T is heated and melted by the fixing roller 40 heated to a constant temperature. Then, the toner image T is fixed on the recording medium P. Therefore, power is supplied from the main power supply 3 and the auxiliary power supply 4 to the main heating element 2a and the auxiliary heating element 2b included in the heating unit 2 of the fixing roller 40, thereby increasing the temperature of the fixing roller 40, and By controlling on / off of the power supplied from the apparatus 4, it is possible to prevent the temperature of the fixing roller 40 from becoming too high, to maintain the fixing temperature at a constant temperature or a desired temperature, or to show a required temperature change. , The toner T is stably heated and melted, and a good quality toner image T is fixed on the recording medium P. Further, since power is supplied from the main power supply device 3 and the auxiliary power supply device 4 to the main heating element 2a and the auxiliary heating element 2b of the heating section 2 incorporated in the fixing roller 40 to increase the temperature of the fixing roller 40, Can be quickly raised to a predetermined fixing temperature. The heating unit 2 may include a plurality of auxiliary heating elements.
[0064]
In the fixing device having such a configuration, in order for the CPU 10 serving as an arithmetic unit to calculate the amount of heat required to bring the recording medium P to the set temperature, the number of sheets passed through the recording medium P, glossiness, color, etc. Can have at least one of the properties. This is because the required amount of heat varies depending on the characteristics of the recording medium P. Further, at least one of the temperature of the recording medium P, the environmental temperature around the fixing device, the environmental temperature in the image forming unit 2 of the image forming apparatus, and the surface properties of the recording medium P such as unevenness can be used. This is because these also affect the required heat.
[0065]
Here, before the recording medium P passes through the nip portion N between the fixing roller 40 and the pressure roller 41 and is heated by the fixing roller 40, the CPU 10 calculates the amount of heat required to bring the fixing roller 40 to the set temperature. When the control means 8 adjusts and controls the amount of power supply to the auxiliary heating element 2b based on the calorific value calculated by the calculation, the recording medium P is fixed to the fixing roller in consideration of the startup state as the fixing device. Since the temperature adjustment of the fixing roller 40 can be completed before passing through the position 40, the amount of power supplied from the auxiliary power supply device 4 to the auxiliary heating element 2b can be kept to a necessary amount.
[0066]
Further, since the fixing roller 40 is deprived of heat by the passing recording medium P, the amount of heat required to reach the set temperature after the recording medium P has passed the position of the fixing roller 40 is calculated. If the amount of power supply to the auxiliary heating element 2b is adjusted and controlled after passing through the recording medium P based on the calorific value calculated by the calculation, the amount of power supplied from the auxiliary power supply device 4 to the auxiliary heating element 2b is also controlled. Can be reduced to the required amount.
[0067]
Further, the amount of heat required to return the fixing roller 40 to the set temperature is calculated in consideration of the amount of heat taken by the recording medium P passing through the position of the fixing roller 40, and the control unit 8 calculates the amount of heat required by the calculation. Even if the amount of power supplied to the auxiliary heating element 2b is adjusted and controlled before the recording medium P passes the position of the fixing roller 40 based on the calculated amount of heat, the auxiliary heating element 2b The amount of power supplied to the power supply can be limited to the required amount. That is, it is possible to anticipate the state after the recording medium P has passed, and control so that unnecessary power is not supplied to the auxiliary heating element 2b.
[0068]
As described above, the operation state of the CPU 10 of the control unit 8 can be selected. However, the operation states (1) to (3) selected by the CPU 10 in the heating unit 2 are:
(1) If the fixing roller 40 needs to be heated to the set temperature and the recording medium P is expected to pass through the nip N within a predetermined time after the set temperature is reached, In a state where the heating by the heating unit 2 is completed and the temperature of the fixing roller 40 is lowered,
(2) If the fixing roller 40 needs to be heated to the set temperature and the recording medium P is not expected to pass through the nip N within a predetermined time after reaching the set temperature, the fixing is performed. When the device starts up, heating ends, and then the fixing operation is not performed immediately.
(3) If it is not necessary to heat the fixing roller 40 to the set temperature and the recording medium P is not expected to pass through the nip portion N within a predetermined time after the temperature reaches the set temperature, the heating is performed. Although the temperature of the fixing roller 40 has dropped due to the completion of the heating by the unit 2, it is not necessary to raise the temperature again by using the auxiliary heating element 2b, and the fixing roller 40 is heated by the amount of the temperature reduction depending on the situation. In a state that I should do
Each corresponds. If the temperature of the fixing roller 40 is adjusted and controlled by assuming these three states, control can be performed in consideration of most states, so that unnecessary power supply can be eliminated.
[0069]
In the fixing device having such a configuration, after the power supply from the auxiliary power supply device 4 to the auxiliary heating element 2b is started, the average power supply per unit time is increased or decreased, and thereafter the power supply is stopped. When the control by the control means 8 as described above is performed, the control can be performed before the recording medium P passes through the nip portion N in any of the control examples described above. This is because the heating of the fixing roller 40 by the heating unit 2 has been completed before the recording medium P passes through the nip N.
[0070]
Of course, the above-described control of the average supply power per unit time may be performed immediately before or after the passage of the recording medium P through the nip portion N. This is because it is clear that when the recording medium P comes into contact with or comes close to the fixing roller 40, heat is taken from the fixing roller 40, and the temperature of the fixing roller 40 decreases, so that more precise control is possible. If the response is high, more precise control can be achieved.
[0071]
In such a fixing device, the control means 8 increases or decreases the average supply power per unit time, in terms of the fixing temperature, that is, the temperature of the fixing roller 40 or the amount of power held by the capacitor C of the auxiliary power supply device 4 or both. By adopting it as a reference, it is possible to further finely adjust the amount of supplied power, similarly to the above-described embodiment of the heating device of the present invention.
[0072]
That is, as shown in FIG. 2, control for increasing or decreasing the average supply power per unit time from the auxiliary power supply 4 to the auxiliary heating element 2b, and turning on / off the power supply from the auxiliary power supply 4 to the auxiliary heating element 2b. By changing the on / off cycle of the switch 9 to be turned on / off, control to increase or decrease the average supply power per unit time is possible. As a criterion for the control means 8 to increase or decrease the average supply power per unit time, The set temperature and the detected temperature of the fixing roller 40, which is the object to be heated by the auxiliary heating element 2b, can be adopted. The detected temperature of the fixing roller 40 may be either the temperature at the start of the power supply or the temperature that changes sequentially after the start of the power supply. The control for increasing or decreasing the average supply power of stabilizing the fixing operation can be adopted. Further, a comparison result between the set temperature of the fixing roller 40 and the detected temperature may be used as a reference. When the comparison result is used as a reference, various modes such as using the temperature difference between the set temperature of the fixing roller 40 and the detected temperature itself as a control reference, and controlling so as to eliminate the temperature difference can be adopted. Although illustration is omitted, in these examples, a unit such as a sensor for detecting the temperature of the fixing roller 40 is required, and the CPU 10 of the control unit 8 needs a function of calculating the detected temperature value.
[0073]
Similarly, as a different criterion for the control means 8 to increase or decrease the average supply power per unit time, the amount of power held by the capacitor C of the auxiliary power supply device 4 can be adopted. In this case, although not shown, means for detecting the voltage of the auxiliary power supply device 4 and a timer are required, and it is possible to use the detected voltage value of the auxiliary power supply device 4 or use the elapsed time after the start of charging. is there.
[0074]
Further, the heating unit 2 includes, in addition to the first auxiliary heating element 2b, a second auxiliary heating element having a different rated power consumption from the first auxiliary heating element 2b. A configuration in which the average supply power per time is increased or decreased can also be adopted. The number of auxiliary heating elements is not limited to two, and it is also possible to employ a combination of the above-described power supply amount control methods. When the amount of power held by the capacitor C of the auxiliary power supply 4 is used as a reference, the control unit 8 determines that the rated power consumption is small when the amount of power held by the capacitor C of the auxiliary power supply 4 becomes equal to or less than the reference amount of power. Control for switching to the larger or larger auxiliary heating element can be adopted, and by combining this with the various control methods described above, the power amount can be adjusted more precisely.
[0075]
Similarly, it is also possible to supply power from the commercial power supply to the auxiliary heating element 2b via the main power supply device 3 so that the control means 8 can also control the power supply from the commercial power supply.
[0076]
In the illustrated example, the nip portion N is formed by two rollers, that is, the fixing roller 40 and the pressure roller 41. However, the fixing device of the present invention and the image forming apparatus using the same have such a configuration. The present invention is not limited thereto, and any type may be used as long as the recording medium P slides on or passes close to the object to be heated, such as a roller and a belt, and a nip portion N formed by a belt and a belt. Further, the present invention is not limited to the illustrated type of image forming apparatus. For example, the present invention is applicable to various types of apparatuses such as a photoconductor having a belt type instead of a drum shape and a color image forming apparatus using an intermediate transfer belt. Applicable.
[0077]
【The invention's effect】
As described above, the heating device according to the present invention, the fixing device using the same, and the image forming apparatus using the fixing device calculate the amount of heat required to bring the object to be heated to the set temperature. Since the control that adjusts the power supply amount from the power storage device to the heating element based on the amount of heat performed is performed, the power supply from the power storage device to the heating element can be performed only by the necessary power amount or by the amount close to the required power amount. It has the effect of becoming.
[Brief description of the drawings]
FIG. 1 is a circuit diagram illustrating a configuration of an embodiment of a heating device according to the present invention.
FIG. 2 is a diagram illustrating an example of increasing or decreasing the average supply power per unit time in the embodiment of the present invention.
FIG. 3 is a diagram showing another example of increasing or decreasing the average supply power per unit time in the embodiment of the present invention.
FIG. 4 is a conceptual sectional view showing an embodiment of the image forming apparatus according to the present invention.
FIG. 5 is a conceptual cross-sectional view illustrating a configuration of a fixing device according to an embodiment of the present invention used in the image forming apparatus of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heating device 2 Heating part 2a Main heating element 2b Auxiliary heating element 3 Main power supply 4 Auxiliary power supply 5 Main switch 6 Charger 7 Switching device 8 Control means 9 Switch 10 CPU
11 Reading Unit 12 Image Forming Unit 13 Automatic Document Feeder (ADF)
14 Document discharge trays 15, 16, 17, 18 Paper feed cassette 19 Paper feed unit 20 Paper discharge tray 21 Document table 25 Reading device 30 Photoconductor 31 Charging device 32 Writing unit 33 Developing device 34 Transfer device 35 Cleaning device 36 Fixing device 37 discharge roller pair 40 fixing roller 41 pressure roller C capacitor D document P recording medium T toner N nip S sensor

Claims

A heating unit, a power storage device for supplying power to the heating unit to heat the heating unit, and a control unit for controlling an operation of the power storage device, wherein the heating unit generates heat by the power supplied from the power storage device In a heating device having a heating element and a capacitor capable of charging / discharging the power storage device, the control means includes an operation means for calculating an amount of heat required to bring the object to be heated to a set temperature. A heating device for controlling the amount of power supplied from the power storage device to the heating element based on the amount of heat calculated by the means.

2. The heating apparatus according to claim 1, wherein the control unit controls the temperature based on a set temperature of the object to be heated by the heating element or a detected temperature of the object to be heated.

3. The heating device according to claim 2, wherein when the control is performed based on the detected temperature of the object to be heated, the detected temperature is one of a temperature at the start of power supply and a temperature changed after the start of power supply. Heating equipment.

4. The heating apparatus according to claim 2, wherein the control means controls the temperature based on a comparison result between a set temperature of the object to be heated and a detected temperature of the object to be heated.

2. The heating device according to claim 1, wherein the control means controls the power storage device in accordance with an amount of stored power.

The heating device according to any one of claims 1 to 5, wherein the calculating means is configured to determine whether the object to be heated by the object to be heated by sliding contact with or near the object to be heated passes through the position of the object to be heated. To calculate the amount of heat required to bring the object to be heated to the set temperature, the control unit, based on the amount of heat calculated by the operation unit, before the object passes through the position of the object to be heated, A heating device, wherein the amount of electric power supplied to the heating element is adjusted.

The heating device according to any one of claims 1 to 5, wherein the calculation means is configured to determine whether the object to be heated by the object to be heated by sliding contact with or near the object to be heated has passed the position of the object to be heated. Calculating the amount of heat required to bring the body to be heated to the set temperature in the above, the control means, based on the amount of heat calculated by the calculation means, after the object has passed the position of the body to be heated, A heating device for adjusting the amount of electric power supplied to a heating element.

The heating device according to any one of claims 1 to 5, wherein the calculation means is configured to determine whether the object to be heated by the object to be heated by sliding contact with or near the object to be heated has passed the position of the object to be heated. Calculating the amount of heat required to bring the body to be heated to a set temperature in the control unit, based on the amount of heat calculated by the calculation unit, before the object passes through the position of the body to be heated, A heating device for adjusting the amount of electric power supplied to a heating element.

The heating device according to any one of claims 1 to 8, wherein the control unit includes an operation state selection unit, and the operation state selected by the selection unit is:
It is expected that the object to be heated needs to be heated to a set temperature, and that the object slides on or passes close to the object to be heated within a predetermined time after reaching the set temperature. And
When heating the object to be heated to the set temperature is necessary, and it is not expected that the object will slide on or be close to the object to be heated within a predetermined time after reaching the set temperature. When,
It is not necessary to heat the object to be heated to the set temperature, and it is expected that the object will slide on or be close to the object to be heated within a predetermined time after reaching the set temperature. Is the case,
The heating device, wherein the selection means selects at least one of the operation states, and the calculation means calculates a heat quantity based on a selection result of the selection means.

The heating device according to any one of claims 1 to 9, wherein the control unit is configured to start and end supply before the object slides on or passes close to the object to be heated; A heating device, comprising: means for setting a ratio of a power supply amount at which supply is started immediately before or after the object passes through the object in sliding contact with or close to the object to be heated.

The heating device according to any one of claims 1 to 10, wherein the control unit performs control for adjusting a power supply time.

12. The heating device according to claim 1, wherein the control unit performs control to increase or decrease an average power supply per unit time from the power storage device to the heating element. Heating equipment.

The heating device according to any one of claims 1 to 12, further comprising means for supplying electric power from a commercial power supply to the heating element.

14. The heating device according to claim 13, wherein the control unit includes a power supply source selection unit, wherein the power supply source selection unit supplies power from the commercial power supply to the heating element, A heating device, which selects one of supplying power to the heating element from both devices.

A fixing device comprising the heating device according to any one of claims 1 to 14, wherein the fixing device heats an image on a recording medium that slides on or passes close to the object to be heated by the heating element.

16. The fixing device according to claim 15, wherein the calculating means calculates a heat amount required to bring the recording medium to a set temperature using at least one of the number of sheets passed through the recording medium, gloss, and color. Fixing device.

17. The fixing device according to claim 15, wherein the calculating unit calculates a heat amount required for setting the recording medium to a set temperature using at least one of a temperature, an environmental temperature, and a surface property of the recording medium. A fixing device.

An image forming apparatus comprising the fixing device according to claim 15.