Abstract: A first rectification circuit is connected to an output side of a first piezoelectric transformer and outputs a voltage of a first polarity. A second rectification circuit is connected to an output side of the second piezoelectric transformer and outputs a voltage of a second polarity. A frequency adjustment unit is connected between the second rectification circuit and an output of the second piezoelectric transformer, and adjusts a relationship between an output voltage and a drive frequency of the second piezoelectric transformer. A driving circuit supplies a drive signal to both the first piezoelectric transformer and the second piezoelectric transformer.

Abstract: A first rectification circuit is connected to an output side of a first piezoelectric transformer and outputs a voltage of a first polarity. A second rectification circuit is connected to an output side of the second piezoelectric transformer and outputs a voltage of a second polarity. A frequency adjustment unit is connected between the second rectification circuit and an output of the second piezoelectric transformer, and adjusts a relationship between an output voltage and a drive frequency of the second piezoelectric transformer. A driving circuit supplies a drive signal to both the first piezoelectric transformer and the second piezoelectric transformer.

Abstract: An image heating apparatus includes a cylindrical film, and a heater having a substrate, and a heat generating element provided on the substrate. The heater has an elongated plate-like shape, and a first surface contacting the film, a second surface opposite to the first surface, and a heater lateral surface facing outwardly in a widthwise direction of the heat generating element. A supporting member supports the heater, and includes a recess and a supporting lateral surface that is parallel to and opposes the heater lateral surface. The supporting lateral surface is provided in the recess, and is bonded to the heater lateral surface using an adhesive material. A high heat conduction member has a thermal conductivity greater than a thermal conductivity of the substrate, and contacts the second surface of the heater and is sandwiched between the heater and the supporting member.

Abstract: An image heating device is provided with a tubular film, and a unit placed inside the film. The unit includes a heater in contact with an inner surface of the film, a supporting member supporting the heater, and a highly thermal conductive member. The highly thermal conductive member placed between the heater and the supporting member and in contact with the heater. The unit is configured such that when the unit is viewed from a side where a surface of the heater is in contact with the film, at least a portion of the highly thermal conductive member is visible without being hidden behind the heater.

Abstract: A negative bias circuit outputs a DC voltage of a negative polarity. A positive bias circuit outputs a DC voltage of a positive polarity. The DC voltage of the positive polarity is used, for example, as a transfer voltage, and the DC voltage of the negative polarity is used as a cleaning voltage for cleaning toner. A cycle of the clock signal in a period during which the DC voltage of the first polarity is output is longer than a cycle of the clock signal in the period during which the voltage supplied to the load transits from the DC voltage of the first polarity to the DC voltage of the first polarity.

Abstract: An image fixing apparatus includes a heater including a substrate, a first electrode provided on one side of the substrate and a second electrode provided on the other side of the substrate; and a connector, connected with the heater, for receiving electric power, the connector including an electrically insulative housing, and a contact terminal provided inside the housing and having first spring contact contacted to the first electrode and a second spring contact contacted to the second electrode, wherein the first spring contact and the second spring contact are disposed at positions different as seen in a direction perpendicular to a surface of the substrate.

Abstract: Until an output voltage of a converter reaches a threshold value, a control part performs switching control, and after the output voltage reaches the threshold value, the control part performs supply voltage control while the state of a switching control signal at the time when the output voltage reaches the threshold value is maintained. Switching control is a control method in which the output voltage is adjusted by adjusting the frequency or duty ratio of the switching control signal that drives a driving part. Supply voltage control is a control method in which the output voltage is adjusted by adjusting the supply voltage that is applied to the primary side of the converter.

Abstract: An image forming apparatus includes a fixing portion for heating and fixing an unfixed image formed on a recording material, the fixing portion including a cylindrical film, a heater provided in an inside space of the film, a switch portion actuatable by heat from the heater, and a protection element for shutting off electric power supplied to the heater; a DC voltage source for generating a DC voltage from a commercial AC voltage source. The protection element is connected in a DC circuit operable by the DC voltage source, and when the switch portion is rendered off, the electric power supply to the heater is shut off.

Abstract: An image forming apparatus includes an image carrier, an image forming unit for forming a patch image on the image carrier, a light emitting unit, a plurality of light receiving units adjacently arranged so as to receive light reflected from the patch image when light is irradiated by the light emitting unit onto the patch image which moves with movement of the image carrier and each including one or more light receiving elements, and an output unit for outputting an output signal that depends on a difference between a received light quantity of a first light receiving unit and a received light quantity of a second light receiving unit that are respectively odd-numbered and even-numbered in the arrangement order of the light receiving units.

Abstract: An image forming apparatus includes an image carrier, an image forming unit configured to form a patch image on the image carrier, and a light emitting unit. In addition, a light receiving unit receives light reflected by the patch image when the patch image that moves with movement of the image carrier is irradiated with light by the light emitting unit, and includes one or more light receiving elements. A setting unit sets a first subset of light receiving elements for receiving reflected light from a first patch image and sets a second subset of light receiving elements for receiving reflected light from a second patch image, with the number of light receiving elements in the first subset differing from that in the second subset.

Abstract: An image heating apparatus includes a heater including a substrate and a heat generating element provided on the substrate; a supporting member supporting the heater, the supporting member being provided with a recess for receiving the heater; a high heat conduction member having a thermal conductivity at least in a direction parallel with a surface higher than a thermal conductivity of the substrate, the high heat conduction member being sandwiched between the heater and the supporting member. A side surface of the heater and a surface, defining the recess and opposing the side surface of the heater, of the supporting member are bonded by adhesive material with each other to fix the heater and the supporting member to each other.

Abstract: An image heating device is provided with a tubular film, and a unit placed inside the film. The unit includes a heater in contact with an inner surface of the film, a supporting member supporting the heater, and a highly thermal conductive member. The highly thermal conductive member placed between the heater and the supporting member and in contact with the heater. The unit is configured such that when the unit is viewed from a side where a surface of the heater is in contact with the film, at least a portion of the highly thermal conductive member is visible without being hidden behind the heater.

Abstract: The image heating apparatus includes an endless belt, a connector and a heater including an insulated substrate, a heat generating resistor, an electrode brought into contact with a contact of the connector; and a conductor provided on a surface of the insulated substrate opposite to a surface on which the electrode wherein the insulated substrate includes multiple through holes electrically connecting the electrode and the conductor to each other, in an area in which the electrode is provided, wherein the distances between a position on the electrode brought into contact with the contact and the multiple through holes are substantially equal to each other, so that burning of the through hole and conduction failure caused by the burning can be prevented.

Abstract: The image heating apparatus includes an endless belt, a connector and a heater including an insulated substrate, a heat generating resistor, an electrode brought into contact with a contact of the connector; and a conductor provided on a surface of the insulated substrate opposite to a surface on which the electrode wherein the insulated substrate includes multiple through holes electrically connecting the electrode and the conductor to each other, in an area in which the electrode is provided, wherein the distances between a position on the electrode brought into contact with the contact and the multiple through holes are substantially equal to each other, so that burning of the through hole and conduction failure caused by the burning can be prevented.

Abstract: An image fixing apparatus includes a heater including a substrate, a first electrode provided on one side of the substrate and a second electrode provided on the other side of the substrate; and a connector, connected with the heater, for receiving electric power, the connector including an electrically insulative housing, and a contact terminal provided inside the housing and having first spring contact contacted to the first electrode and a second spring contact contacted to the second electrode, wherein the first spring contact and the second spring contact are disposed at positions different as seen in a direction perpendicular to a surface of the substrate.

Abstract: An image forming apparatus includes a fixing portion for heating and fixing an unfixed image formed on a recording material, the fixing portion including a cylindrical film, a heater provided in a cylindrical shape of the film, a switch portion actuatable by heat from the heater, and a protection element for shutting off electric power supplied to the heater; a DC voltage source for generating a DC voltage from commercial AC voltage source, wherein the protection element is disposed in the shape of cylinder of the film is connected in a DC circuit operable by the DC voltage source, and wherein when the switch portion is rendered off, the electric power supply to the heater is shut off.

Abstract: An image fixing apparatus includes a heater including a substrate, a first electrode provided on one side of the substrate and a second electrode provided on the other side of the substrate; and a connector, connected with the heater, for receiving electric power, the connector including an electrically insulative housing, and a contact terminal provided inside the housing and having first spring contact contacted to the first electrode and a second spring contact contacted to the second electrode, wherein the first spring contact and the second spring contact are disposed at positions different as seen in a direction perpendicular to a surface of the substrate.

Abstract: A negative bias circuit outputs a DC voltage of a negative polarity. A positive bias circuit outputs a DC voltage of a positive polarity. The DC voltage of the positive polarity is used, for example, as a transfer voltage, and the DC voltage of the negative polarity is used as a cleaning voltage for cleaning toner. A cycle of the clock signal in a period during which the DC voltage of the first polarity is output is longer than a cycle of the clock signal in the period during which the voltage supplied to the load transits from the DC voltage of the first polarity to the DC voltage of the first polarity.

Abstract: A power supply apparatus with a plurality of power supply circuits each having a piezoelectric transformer and a voltage-controlled oscillator which generates a signal at an operating frequency used to drive the piezoelectric transformer in accordance with a control signal, includes a frequency-dividing circuit which divides the operating frequency generated by a voltage-controlled oscillator in at least one power supply circuit, and outputs a signal at a driving frequency to drive a piezoelectric transformer in the one power supply circuit. When at least one power supply circuit and remaining power supply circuits output voltages, the operating frequency generated by the voltage-controlled oscillator in the one power supply circuit is controlled to be higher than the operating frequency generated by the voltage-controlled oscillator in another power supply circuit.

Abstract: A power supply apparatus with a plurality of power supply circuits each having a piezoelectric transformer and a voltage-controlled oscillator which generates a signal at an operating frequency used to drive the piezoelectric transformer in accordance with a control signal, includes a frequency-dividing circuit which divides the operating frequency generated by a voltage-controlled oscillator in at least one power supply circuit, and outputs a signal at a driving frequency to drive a piezoelectric transformer in the one power supply circuit. When at least one power supply circuit and remaining power supply circuits output voltages, the operating frequency generated by the voltage-controlled oscillator in the one power supply circuit is controlled to be higher than the operating frequency generated by the voltage-controlled oscillator in another power supply circuit.