JP2004088965A - High-voltage power supply - Google Patents
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Abstract
Description
【0001】
【発明の属する技術分野】
本発明は、電子写真プロセスを用いた複写機・ファクシミリ・プリンタ等の画像形成装置に好適な高圧電源に関するものである。
【0002】
【従来の技術】
電子写真プロセスによる複写機・ファクシミリ・プリンタ等の画像形成装置には、マイクロプロセッサCPUとタイマ、A/D変換器を備え、各高電圧出力をA/D変換器によりモニタし、一定周期毎にA/D変換からの現出力帰還値と目標出力との比較結果からCPUによる演算更新を行い、高圧トランスを駆動するスイッチングトランジスタのスイッチングデューティを制御することで任意の高電圧を出力する高圧電源が搭載されている。
電子写真プロセスの高圧電源の出力及び負荷は、電圧印加対象のローラや感光体そのもののインピーダンスが広範囲になっていること、また、画像品質向上のために装置がおかれた環境や記録紙の種類、サイズにより出力設定値が異なることが多いため、非常に広範囲となる。
このように、出力範囲・負荷範囲が広いものに対して一定の制御を行っていると、負荷インピーダンスが大きく変化した場合や目標出力の切り替えを行った場合に出力が追従できず、画像に影響を及ぼす可能性がある。
このような問題に対し、特開平8−187918号公報に記載の技術では、あらかじめ対象負荷に任意の出力を段階的に印加し、PWMデューティを把握しておき、その対象負荷に最適なPWMデューティを狙って制御することで起動特性の最適化や高精度な出力を達成しようとしている。
【0003】
【発明が解決しようとする課題】
しかし、画像転写の際に記録紙のサイズ、種類によって大きくインピーダンスが異なる。また、転写ローラによってはローラ自体のインピーダンスの環境依存性が大きく、実際の転写動作時の負荷が各条件によって異なっている場合が多く、一定の制御を行っている時にはオーバーシュートや立ち上がり時間などの起動特性に違いが出てくる。
また、記録紙の後端が搬送ローラを抜けた際に紙の挙動により転写ニップでの状態が変化することによる画像へ影響を抑えるため、転写出力の設定をそのタイミングで切り替えるものがある。その場合に、出力値の切り替え幅は一定とはならず、切り替え幅が大きい、もしくは追従性が悪ければ、切り替え時間が画像に影響する範囲となる(切り替え時間の間、画像に悪影響がある)ため、切り替え時間はできる限り短時間となることが望ましい。
本発明は、出力の切り替え時間を短くすることができる高圧電源を提供することを目的とする。
【0004】
【課題を解決するための手段】
上記目的を達成するために、請求項1記載の発明は、オン・オフデューティを任意に設定可能なPWM発生手段と、該PWM発生手段によりトランスを駆動することでデューティに応じた出力を発生する高圧出力発生手段と、出力電流及び出力電圧の帰還値と制御すべき目標値とを一定周期毎に比較し、所定の演算式により次周期のPWMデューティを更新する制御手段と、を備えた高圧電源において、前記制御手段は、出力電流及び出力電圧の帰還値から高圧負荷のインピーダンスを算出し、高圧出力中に出力値を切り替える際に算出したインピーダンスと出力切り替え前後での出力設定値の差分から演算式を変更する制御を行うことを特徴とする。
請求項2記載の発明は、請求項1記載の高圧電源において、制御手段は、インピーダンス算出及び出力切り替え時の演算係数変更を記録紙1枚ごとに実行する高圧電源を主要な特徴とする。
請求項3記載の発明は、請求項1記載の高圧電源において、制御手段は、出力切り替え時の帰還値から切り替え時間を計測し、所定の時間を超える場合は出力切り替え時の演算係数を補正する高圧電源を主要な特徴とする。
請求項4記載の発明は、請求項1記載の高圧電源において、制御手段は、出力切り替え時の帰還値からオーバーシュート及びアンダーシュートを計測し、所定の量を超える場合は出力切り替え時の演算係数を補正する高圧電源を主要な特徴とする。
【0005】
【発明の実施の形態】
以下、図面により本発明の実施の形態を詳細に説明する。
図1は本発明の実施の形態に係る高圧電源のブロック図である。CPU1は記録紙搬送のためのモータ制御や各種センサの取り込み、光書き込み制御等の装置全体の制御を行うとともに、内部にタイマ機能を備え、一定間隔で発生するタイマ割り込み時に高圧電源の駆動条件を演算更新し、PWM発生器2により必要な駆動条件でスイッチングトランジスタをon/offさせ、高圧発生部4により出力を発生する。
これにより高圧出力端子に印加される出力を帰還値変換部5により出力電圧及び出力電流モニタするために変換し、A/D変換器3により取り込み、このA/D変換の結果により駆動条件をCPU1が演算更新する制御を高圧出力停止タイミングまで繰り返し行う。
温湿度センサ7はこの装置が置かれた環境条件を把握するためのセンサであり、A/D変換器3により温度及び湿度を取り込む。この情報により転写ローラのインピーダンスを予測するとともに記録紙の吸湿状態を把握することが可能になる。記録紙サイズセンサ6は数ビットのSWによって構成され7〜8種の定型紙サイズを検知し画像領域の設定、転写ローラに印加する高圧出力値を決定する。
【0006】
基本的な演算更新について図2に従い説明する。CPU1は出力開始タイミング(フラグによる判定)ならば(201Y)、演算更新の同期をとるために内部のタイマ割り込み(ここでは10ms割り込み)が入ったところ(202Y)で現在の出力をA/D変換によって取り込み(203)、目標出力のA/D値との差分を求め(204)、所定の演算式1に従って更新するPWM設定値を計算し(205)、PWM更新駆動する。これは10ms毎に出力が停止されるまで継続して行われる。
計算式は上記で求めたA/D値の目標値との差分にある演算係数を掛け、現在のPWM設定値に対して増加減する。具体的には式1:新PWM設定値=現PWM設定値+(A/D値差分×演算係数)となっており、出力が目標出力に対して小さい場合はPWMデューティのon幅が大きくなる様に、逆に出力が目標出力に対して大きい場合はPWMデューティのon幅が小さくなる様に演算される。また、A/Dの差分が大きければ、PWMデューティの増減分も大きくなり、小さければ増減分は小さく更新される。
実際の高圧出力では、出力開始のタイミングにおいて、初期固定PWM設定値で駆動を開始し、その時の出力に対するfb値をA/D変換し、次周期のPWMを演算する。この初期PWM設定値と目標出力値及び負荷条件によって立ち上がり時間やオーバーシュート等の起動特性が決まってくる。例えば、立ち上がり時間を早くしようとすれば初期PWM設定値を大きくすることで可能になるが、負荷が小さい場合にはオーバーシュートを発生する要因となる。
また、同様に演算係数によっても立ち上がり時間は変わってくる。このように起動特性は負荷条件が支配的に作用するため、この負荷条件にあった初期PWM設定値、演算係数を設定する。この制御方式を基本とする場合、高圧電源から見て負荷として重い場合を想定すると、出力の立ち上がり時間を考えるとき、演算係数はある程度更新幅が大きくなるように設定して置く必要がある。例えば演算係数を1/10としておく、演算式によれば出力帰還値と目標値との差(目標値−取り込み帰還値)が30となれば、PWMは現在の設定から+3した値となる。
【0007】
つまり、演算係数を1/5と大きくすれば帰還値が同量変化してもPWMの更新幅は大きくなり、インピーダンスが同じと想定すれば、出力変化量も大きくなる。逆に1/20と小さくすれば出力変化量も小さくなる。ただし、PWMの更新幅が同じ場合、出力の変化量は当然インピーダンスに依存する。ここでは画像転写に際し、定電流によりバイアスを印加する場合を例にPWM演算式の演算係数を切り替えて制御する方法を説明する。
記録紙への画像転写の際に、記録紙途中で設定電流を変化させることで画像品質を向上させようとする場合、印加中の電流・電圧を取り込みインピーダンスを算出しておき、切り替えタイミングで算出されたインピーダンスと切り替えの設定値差から演算式に使用する演算係数を変更し、追従性の向上を図る。例えば通常時に演算係数1/10で制御しているところから、記録紙の先端から切り替えタイミングまでのインピーダンス平均を算出し、インピーダンスが50MΩ以下を算出した場合、出力電流の目標設定の差分Δi=10μAより小さい場合にはPWM変化幅は少なく済むはずであり、演算係数を1/20と小さくする必要がある。
演算係数が大きいままだと変化時のオーバーシュート・アンダーシュートが発生し、画像に影響するとともに出力が安定しない可能性がある。同じインピーダンスが50MΩ以下を算出した場合でも出力電流の目標設定の差分Δiが10μA以上、20μA以下であれば演算係数を1/18とすることで追従性を若干、向上させる。更に算出したインピーダンスが300MΩより大きく、切り替え時の設定値との差分が大きい場合(Δi=20μAより大きい)に演算係数は最大となり、追従性を良くすることで、切り替わり時間を減少させ、画質を向上させる。
このように記録紙のインピーダンスを測定し、測定したインピーダンスと切り替える出力値の差分から演算式を決定し制御する。また、このような場合でも切り替えた目標値からある範囲に帰還値が近づいたところで演算係数を、安定制御できるある程度小さいものに設定し演算更新することでより安定した出力制御が可能となる。
また、この出力切り替え時に帰還値から切り替えられた目標値へ収束するつまり、目標値からある範囲の帰還値となるまでの時間を計測する手段と、オーバーシュートもしくはアンダーシュート量を計測する手段とを備えて、目標値への収束時間が所定に時間を超えた場合に、使用する演算係数を一段階大きくすることで、追従速度をあげる。逆に切り替え時にオーバーシュートもしくはアンダーシュートしてしまうのであれば、使用する演算係数を一段階小さくすることでこれを防ぐ。図3に演算係数テーブルを示す。
【0008】
【発明の効果】
以上説明したように、請求項1記載の発明によれば、出力電流及び出力電圧の帰還値から算出したインピーダンスと出力切り替え目標値の差分から切り替え時の演算式を決定し制御するので、出力の切り替わり時間を短くすることができ、画像形成装置に適用して画質の向上を図ることができる。
請求項2記載の発明によれば、インピーダンス算出を記録紙1枚毎に実施して切り替え時の演算式を決定し制御するので、環境や記録紙の違いを吸収できるとともに連続動作時にも最適な演算式で出力の切り替わり時間を短くすることができ、画像形成装置に適用して画質の向上を図ることができる。
請求項3記載の発明によれば、切り替え時の出力帰還値から切り替え時間を計測し、演算式を補正するので出力の切り替わり時間を管理でき、画像形成装置に適用して画質の向上を図ることができる。
請求項4記載の発明によれば、切り替え時の出力帰還値からオーバーシュート及びアンダーシュートを計測し、演算式を補正するので出力の切り替わり時の画像劣化を最小限に抑えることができる。
【図面の簡単な説明】
【図1】本発明の実施の形態に係る高圧電源のブロック図である。
【図2】本発明の制御動作を示すフローチャートである。
【図3】演算係数テーブルを示す図である。
【符号の説明】
1 CPU(制御手段)
2 PWM発生器(PWM発生手段)
4 高圧発生部(高圧出力発生手段)[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-voltage power supply suitable for an image forming apparatus such as a copying machine, a facsimile, and a printer using an electrophotographic process.
[0002]
[Prior art]
2. Description of the Related Art An image forming apparatus such as a copying machine, a facsimile, a printer, or the like using an electrophotographic process includes a microprocessor CPU, a timer, and an A / D converter, and monitors each high-voltage output by the A / D converter. A high-voltage power supply that outputs an arbitrary high voltage by controlling the switching duty of a switching transistor that drives a high-voltage transformer by performing a calculation update by the CPU based on a comparison result between the current output feedback value from the A / D conversion and the target output, and It is installed.
For the output and load of the high-voltage power supply in the electrophotographic process, the impedance of the roller to which the voltage is applied and the photoreceptor itself have a wide range, and the environment and the type of recording paper in which the device is placed to improve image quality In many cases, the output setting value differs depending on the size, so that the output setting value is very wide.
In this way, if constant control is performed for a wide output range and load range, the output cannot follow when the load impedance changes significantly or when the target output is switched, which may affect the image. May be affected.
To cope with such a problem, in the technique described in Japanese Patent Application Laid-Open No. 8-187918, an arbitrary output is applied to a target load in a stepwise manner, the PWM duty is grasped in advance, and the optimum PWM duty for the target load is obtained. The aim is to optimize the startup characteristics and achieve high-precision output by controlling the system.
[0003]
[Problems to be solved by the invention]
However, the impedance greatly differs depending on the size and type of the recording paper during image transfer. In addition, depending on the transfer roller, the impedance of the roller itself largely depends on the environment. In many cases, the load during the actual transfer operation differs depending on each condition. There is a difference in startup characteristics.
Further, in order to suppress the influence on the image due to a change in the state of the transfer nip due to the behavior of the paper when the trailing edge of the recording paper passes through the transport roller, there is a type in which the setting of the transfer output is switched at that timing. In this case, the switching width of the output value is not constant, and if the switching width is large or the tracking performance is poor, the switching time is in a range that affects the image (the image is adversely affected during the switching time). Therefore, it is desirable that the switching time be as short as possible.
An object of the present invention is to provide a high-voltage power supply capable of shortening the output switching time.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 generates a PWM generating means capable of arbitrarily setting an on / off duty, and generates an output according to the duty by driving a transformer by the PWM generating means. A high-voltage output generating means, and a control means for comparing a feedback value of the output current and the output voltage with a target value to be controlled at regular intervals and updating the PWM duty of the next cycle by a predetermined arithmetic expression. In the power supply, the control means calculates the impedance of the high-voltage load from the feedback values of the output current and the output voltage, and calculates the impedance between the output value and the output set value before and after the output switching during the high-voltage output. It is characterized in that control for changing the arithmetic expression is performed.
According to a second aspect of the present invention, in the high-voltage power supply according to the first aspect, the control means is characterized mainly by a high-voltage power supply which executes impedance calculation and calculation coefficient change at the time of output switching for each recording sheet.
According to a third aspect of the present invention, in the high-voltage power supply according to the first aspect, the control unit measures a switching time from a feedback value at the time of output switching, and corrects a calculation coefficient at the time of output switching when the output time exceeds a predetermined time. High voltage power supply is the main feature.
According to a fourth aspect of the present invention, in the high-voltage power supply according to the first aspect, the control means measures overshoot and undershoot from a feedback value at the time of output switching, and calculates an operation coefficient at the time of output switching when exceeding a predetermined amount. The main feature is a high-voltage power supply that compensates for
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram of a high-voltage power supply according to an embodiment of the present invention. The CPU 1 controls the entire apparatus, such as motor control for transporting recording paper, taking in of various sensors, and optical writing control, and also has a timer function inside, and determines the driving conditions of the high-voltage power supply when a timer interrupt occurs at regular intervals. The operation is updated, the switching transistor is turned on / off under a necessary driving condition by the PWM generator 2, and an output is generated by the high voltage generator 4.
As a result, the output applied to the high voltage output terminal is converted by the feedback value converter 5 for monitoring the output voltage and output current, captured by the A / D converter 3, and the driving conditions are determined by the CPU 1 based on the result of the A / D conversion. Is repeatedly performed until the high-voltage output stop timing.
The temperature / humidity sensor 7 is a sensor for grasping the environmental conditions in which this device is placed, and takes in the temperature and humidity by the A / D converter 3. Based on this information, it is possible to predict the impedance of the transfer roller and to grasp the moisture absorption state of the recording paper. The recording paper size sensor 6 comprises several bits of SW, detects seven to eight types of standard paper sizes, sets an image area, and determines a high voltage output value to be applied to the transfer roller.
[0006]
The basic operation update will be described with reference to FIG. If the output start timing (judgment based on the flag) (201Y), the CPU 1 converts the current output into an A / D signal at the point where an internal timer interrupt (here, a 10 ms interrupt) is inserted (202Y) in order to synchronize the operation update. (203), a difference between the target output and the A / D value is obtained (204), and a PWM set value to be updated is calculated according to a predetermined arithmetic expression 1 (205), and PWM update driving is performed. This is continued until the output is stopped every 10 ms.
The calculation formula multiplies the difference between the calculated A / D value and the target value by an operation coefficient, and increases or decreases the current PWM set value. Specifically, Equation 1: New PWM set value = Current PWM set value + (A / D value difference × Operation coefficient), and when the output is smaller than the target output, the ON width of the PWM duty becomes larger. Similarly, when the output is larger than the target output, the calculation is performed so that the on-width of the PWM duty becomes smaller. Also, if the difference between A / D is large, the increase or decrease of the PWM duty becomes large, and if the difference is small, the increase or decrease is updated small.
In the actual high-voltage output, at the output start timing, driving is started with the initial fixed PWM set value, the fb value for the output at that time is A / D converted, and the PWM of the next cycle is calculated. Starting characteristics such as a rise time and an overshoot are determined by the initial PWM set value, the target output value, and the load condition. For example, if the rise time is to be shortened, this can be achieved by increasing the initial PWM set value. However, when the load is small, overshoot is a factor.
Similarly, the rise time also changes depending on the operation coefficient. As described above, since the load condition has a dominant effect on the start-up characteristic, an initial PWM set value and a calculation coefficient corresponding to the load condition are set. In the case of this control method as a base, if it is assumed that the load is heavy when viewed from the high-voltage power supply, it is necessary to set the operation coefficient so that the update width becomes large to some extent when considering the rise time of the output. For example, if the operation coefficient is set to 1/10, according to the operation formula, if the difference between the output feedback value and the target value (target value-capture feedback value) is 30, PWM will be a value obtained by +3 from the current setting.
[0007]
That is, if the operation coefficient is increased to 1/5, the PWM update width increases even if the feedback value changes by the same amount, and if the impedance is assumed to be the same, the output change amount also increases. Conversely, if it is reduced to 1/20, the amount of output change is also reduced. However, when the PWM update width is the same, the amount of change in the output naturally depends on the impedance. Here, a method of switching and controlling the operation coefficient of the PWM operation expression will be described by taking as an example a case where a bias is applied by a constant current at the time of image transfer.
When trying to improve image quality by changing the set current in the middle of the recording paper when transferring the image to the recording paper, the current and voltage being applied are taken in, the impedance is calculated, and calculated at the switching timing. The operation coefficient used in the operation expression is changed from the difference between the set impedance and the set value of the switching, thereby improving the followability. For example, since the control is performed with the operation coefficient 1/10 in the normal state, the impedance average from the leading edge of the recording paper to the switching timing is calculated, and when the impedance is calculated to be 50 MΩ or less, the difference Δi of the target setting of the output current Δi = 10 μA If it is smaller, the PWM change width should be small, and the operation coefficient needs to be reduced to 1/20.
If the arithmetic coefficient remains large, overshoot / undershoot at the time of change occurs, which may affect the image and unstable output. Even when the same impedance is calculated to be 50 MΩ or less, if the difference Δi in the target setting of the output current is 10 μA or more and 20 μA or less, the followability is slightly improved by setting the operation coefficient to 1/18. Further, when the calculated impedance is greater than 300 MΩ and the difference from the set value at the time of switching is large (greater than Δi = 20 μA), the operation coefficient becomes maximum, and the switching time is reduced by improving the followability, thereby improving the image quality. Improve.
In this way, the impedance of the recording paper is measured, and an arithmetic expression is determined and controlled from the difference between the measured impedance and the output value to be switched. Even in such a case, more stable output control can be achieved by setting the operation coefficient to a value small enough for stable control and updating the operation when the feedback value approaches a certain range from the switched target value.
Further, at the time of this output switching, means for converging from the feedback value to the switched target value, that is, means for measuring a time from the target value to a feedback value in a certain range, and means for measuring the amount of overshoot or undershoot are provided. When the convergence time to the target value exceeds a predetermined time, the following coefficient is increased by increasing the operation coefficient used by one step. Conversely, if overshoot or undershoot occurs during switching, this is prevented by reducing the operation coefficient used by one step. FIG. 3 shows an operation coefficient table.
[0008]
【The invention's effect】
As described above, according to the first aspect of the present invention, the switching operation formula is determined and controlled from the difference between the impedance calculated from the feedback values of the output current and the output voltage and the output switching target value. The switching time can be shortened, and the image quality can be improved by applying to the image forming apparatus.
According to the second aspect of the present invention, the impedance calculation is performed for each sheet of recording paper, and the arithmetic expression at the time of switching is determined and controlled. The switching time of the output can be shortened by the arithmetic expression, and the image quality can be improved by applying to the image forming apparatus.
According to the third aspect of the present invention, the switching time is measured from the output feedback value at the time of switching and the arithmetic expression is corrected, so that the output switching time can be managed, and the image quality can be improved by applying to the image forming apparatus. Can be.
According to the fourth aspect of the present invention, overshoot and undershoot are measured from the output feedback value at the time of switching, and the arithmetic expression is corrected, so that image degradation at the time of output switching can be minimized.
[Brief description of the drawings]
FIG. 1 is a block diagram of a high-voltage power supply according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a control operation of the present invention.
FIG. 3 is a diagram showing an operation coefficient table.
[Explanation of symbols]
1 CPU (control means)
2 PWM generator (PWM generation means)
4 High voltage generator (high voltage output generating means)
Claims (4)
前記制御手段は、出力電流及び出力電圧の帰還値から高圧負荷のインピーダンスを算出し、高圧出力中に出力値を切り替える際に算出したインピーダンスと出力切り替え前後での出力設定値の差分から演算式を変更する制御を行うことを特徴とする高圧電源。PWM generation means capable of arbitrarily setting on / off duty, high-voltage output generation means for generating an output according to duty by driving a transformer by the PWM generation means, feedback values and control of output current and output voltage Control means for comparing a target value to be performed with a target value at regular intervals and updating the PWM duty of the next cycle by a predetermined arithmetic expression.
The control means calculates the impedance of the high-voltage load from the output current and the feedback value of the output voltage, and calculates an arithmetic expression from the difference between the impedance calculated when the output value is switched during the high-voltage output and the output set value before and after the output switching. A high-voltage power supply characterized by performing control for changing.
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JP2002249566A JP2004088965A (en) | 2002-08-28 | 2002-08-28 | High-voltage power supply |
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JP2002249566A JP2004088965A (en) | 2002-08-28 | 2002-08-28 | High-voltage power supply |
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2007049889A (en) * | 2005-07-12 | 2007-02-22 | Brother Ind Ltd | Power supply device and image forming apparatus |
JP2009291047A (en) * | 2008-05-30 | 2009-12-10 | Brother Ind Ltd | Power supply, and image forming apparatus with the same |
US20120027448A1 (en) * | 2010-07-30 | 2012-02-02 | Canon Kabushiki Kaisha | High-voltage generation apparatus |
US8145085B2 (en) | 2008-03-28 | 2012-03-27 | Brother Kogyo Kabushiki Kaisha | Image forming apparatus |
US20130070484A1 (en) * | 2011-09-16 | 2013-03-21 | Canon Kabushiki Kaisha | High voltage generating device and image forming apparatus |
CN110505743A (en) * | 2019-09-11 | 2019-11-26 | 上海联影医疗科技有限公司 | Tube filament electric current output control system |
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2002
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Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2007049889A (en) * | 2005-07-12 | 2007-02-22 | Brother Ind Ltd | Power supply device and image forming apparatus |
JP4720612B2 (en) * | 2005-07-12 | 2011-07-13 | ブラザー工業株式会社 | Power supply apparatus and image forming apparatus |
US8145085B2 (en) | 2008-03-28 | 2012-03-27 | Brother Kogyo Kabushiki Kaisha | Image forming apparatus |
JP2009291047A (en) * | 2008-05-30 | 2009-12-10 | Brother Ind Ltd | Power supply, and image forming apparatus with the same |
JP4683074B2 (en) * | 2008-05-30 | 2011-05-11 | ブラザー工業株式会社 | Power supply device and image forming apparatus having the same |
US8004261B2 (en) | 2008-05-30 | 2011-08-23 | Brother Kogyo Kabushiki Kaisha | Power supply unit and image forming apparatus including the same |
US20120027448A1 (en) * | 2010-07-30 | 2012-02-02 | Canon Kabushiki Kaisha | High-voltage generation apparatus |
US9182708B2 (en) * | 2010-07-30 | 2015-11-10 | Canon Kabushiki Kaisha | High-voltage generation apparatus |
US20130070484A1 (en) * | 2011-09-16 | 2013-03-21 | Canon Kabushiki Kaisha | High voltage generating device and image forming apparatus |
US9075368B2 (en) | 2011-09-16 | 2015-07-07 | Canon Kabushiki Kaisha | High voltage generating device and image forming apparatus |
CN110505743A (en) * | 2019-09-11 | 2019-11-26 | 上海联影医疗科技有限公司 | Tube filament electric current output control system |
CN110505743B (en) * | 2019-09-11 | 2024-05-14 | 上海联影医疗科技股份有限公司 | Bulb tube filament current output control system |
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