Canon Kabushiki Kaisha

Yusuke Isomi

Masatoshi Itoh

Hiroshi Mano

Minoru Hayasaki

Aoji Isono

Akira Kuroda

Takaaki Tsuruya

Yuki Nishizawa

Shigeru Kameyama

Yuichiro Hori

A fixing apparatus to fix a toner image formed on a recording material to the recording material includes a rotatable member having a heat generation layer, a power supply circuit, and a control unit. The power supply circuit supplies electrical power to the rotatable member. The control unit controls supply of electrical power to the rotatable member and detects a change rate of electrical resistance of the heat generation layer. The heat generation layer generates heat by the electrical power supplied to the rotatable member, and the toner image on the recording material is fixed to the recording material by the heat from the heat generation layer. If the change rate of the electrical resistance to the supplied electrical power is higher than a predetermined threshold, the control unit stops the supply of electrical power to the rotatable member.

Fixing apparatus

A motor control apparatus, including: a current detection unit configured to detect a current flowing through a coil of a motor; a voltage application unit configured to apply a voltage to the coil; and a control unit configured to control the voltage application unit by outputting a PWM signal in order to rotate the motor at a predetermined rotation speed, wherein the control unit detects a rotation state of the motor based on a duty of the PWM signal and a current value detected by the current detection unit.

Motor control apparatus and image forming apparatus

In a motor control apparatus, an exciting unit excites a plurality of excitation phases of a motor. A current measurement unit measures exciting currents flowing through coils of respective phases of the motor, and generates measurement data including measurement values of the exciting currents. A determination unit determines whether or not noise is superimposed on a measurement value included in the measurement data by comparing, with respect to each of the plurality of excitation phases, the measurement data regarding a first phase coil that constitutes that excitation phase with the measurement data regarding a second phase coil that constitutes that excitation phase.

The voltage detection apparatus includes a transformer, in which a primary side and a secondary side are insulated from each other and the primary side connected in parallel with a first line and a second line, configured to output from the secondary side a voltage supplied to the primary side according to an alternating voltage; a detection circuit configured to detect a frequency of an alternating voltage; and a correction unit configured to acquire information corresponding to a voltage output from the transformer and information corresponding to a frequency detected by the detection circuit, and that corrects the information corresponding to the voltage according to the information corresponding to the frequency.

Voltage detection apparatus and image forming apparatus

A fixing apparatus configured to include a rotational member having a conductive layer, a coil having a helical shape, a resonance circuit including a resonance capacitor and configured to be formed together with the rotational member and the coil, a first converter driving the resonance circuit, a second converter used to control power to be supplied to the first converter, a frequency setting unit configured to set a driving frequency of the first converter according to at least one of a size of the recording material and a temperature at a sheet non-passing portion of the rotational member, and a power control unit controlling the second converter according to a temperature at a sheet passing portion of the rotational member to control the power to be supplied to the first converter from the second converter, wherein the conductive layer is caused to generate heat by electromagnetic induction.

A fixing apparatus includes a tubular rotation member including a conductive layer, a helical coil, a resonance circuit, including a resonance capacitor, formed with the rotation member and the coil, a resonance inverter configured to control the resonance circuit, and a control unit configured to control electric power supplied to the resonance inverter, wherein the conductive layer generates heat with electromagnetic induction caused by magnetic flux generated through the coil, wherein the control unit sets a driving frequency of the resonance inverter according to at least one of a size of the recording medium and a temperature of a non-sheet-passing portion of the rotation member, and wherein the control unit changes a resonance frequency of the resonance circuit according to the set driving frequency.

In a fixing device, an alternating current is caused to flow through a coil so as to causes an electrically conductive layer of a rotating member to generate heat, and an unfixed image on a recording medium is heat fixed onto the recording medium by the heat generated by the electrically conductive layer. A frequency range of the alternating current is from 20.5 kHz to 100 kHz. With respect to a generatrix direction of the rotating member, a magnetic member and a spirally shaped portion of the coil have lengths, with which the magnetic member and the spirally shaped portion extend beyond both end portions of the rotating member.

Growing community of inventors

Yokohama, Japan

Yusuke Isomi