Ricoh Company, Ltd.

Other

Tohoku Ricoh Co., Ltd.

Hiroto Ohishi

Naoki Sato

Masahide Nakaya

Keiichi Sugai

Masae Sugawara

Yuusuke Ishizaki

Ryo Takamatsu

Jiro Oouchi

An image forming apparatus for forming an image with a fixing member, which fixing member includes a first heating member and a plurality of second heating members is disclosed. The image forming apparatus includes a capacitor, a charging part for charging the capacitor, a first drive part for lighting on/off the first heating member by controlling a first power supply to the first heating member, a second drive part for lighting on/off at least one of the plurality of second heating members by controlling a second power supply to the plurality of second heating members, and a control part for dividing the plurality of second heating members into groups and permitting at least one of the groups to receive the second power supply during a waiting period of the image forming apparatus.

Image forming apparatus for forming image with fixing device power supply control method for controlling the image forming apparatus and power supply control program for controlling the image forming apparatus

Image forming apparatus for forming image with fixing member, power supply control method for controlling the image forming apparatus, and power supply control program for controlling the image forming apparatus

A power source control apparatus including a capacitor; a charge control circuit for controlling a charger that charges the capacitor; a discharging circuit for discharging power charged in the capacitor to a heating member for heating. The power source control apparatus is shifted to an energy saving mode in which power supply to a part of power loads is stopped when a first condition is satisfied, and the power source control apparatus terminates the energy saving mode when a second condition is satisfied. In the apparatus, the charge control circuit is supplied with power from a power source circuit that supplies power during the energy saving mode.

Power source control apparatus, and power source control method

A main controller controls a capacitor charger to charge a capacitor as necessary. A sub-controller controls a power saving mode and stops a power supply to the main controller when shifting to the power saving mode. A charge control circuit compares a terminal voltage of the capacitor with a predetermined value by a comparator circuit. If the terminal voltage is lower than the reference value, an AND circuit takes a logical product of an output signal of the comparator circuit and a power saving signal indicating the shift to the power saving mode, and outputs a control signal indicating an instruction to charge the capacitor, to the capacitor charger.

Heating unit, auxiliary power unit, fixing unit, and image forming apparatus

An induction heating device includes a plurality of induction coils connected to a single high-frequency power source and each being able to be ON/OFF controlled by a switch. A current is selectively fed only to desired part of the induction coils or to all of the induction coils connected in parallel. The coils are driven by a current fed thereto at the same time in the same phase. The device may include inverters for controlling power to be fed coil by coil. The device is free from interference and irregular heating and can readily cope with a change in a heating range while controlling power coil by coil.

Induction heating device with a switching power source and image processing apparatus using the same

Synchronous rectifier circuits are provided for each secondary windings of a transformer. Field-effect transistors of which ON voltage is lower than the forward voltage of a diode are provided in each of the synchronous rectifier circuits. In an energy saving mode, the field-effect transistors in the synchronous rectifier circuit that outputs a diving voltage are turned OFF. A comparator circuit outputs a signal corresponding to a difference between a control voltage output from one of the synchronous rectifier circuits and a reference voltage. Based on this signal, a pulse-width modulation control circuit ON/OFF controls a field-effect transistor provided corresponding to a primary winding of a transformer in such a manner that the control voltage the reference control voltage attain predetermined levels.

Power circuit and method for controlling drive and control voltages of an image formation apparatus

A fixing device for an image forming apparatus includes an inverter circuit for induction heating. In the inverter circuit, a main switch Q drives one end of a work coil L whose other end is connected to a power source. A serial connection of a capacitor Cs and a subswitch Q is connected to opposite ends of the coil L in parallel such that one end of the capacitor Cs is connected to the power source E. A second capacitor C is connected to the subswitch Q in parallel. For a capacitance of 0.1 &mgr;F of the capacitor C , the factor of the coil L and that of the capacitor Cs are selected to be between 70 &mgr;H and 100 &mgr;H and between 1.8 &mgr;F and 5 &mgr;F, respectively. The inverter circuit is operable with optimal efficiency in the event of PWM (Pulse Width Modulation) control using a fixed frequency.

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Kanagawa, Japan

Hiroto Ohishi