Canon Kabushiki Kaisha

Junichi Kubota

Tomoo Akizuki

Masahiko Suzumi

Takayuki Kanazawa

Tatsuya Kinukawa

Yusuke Nakazono

Ryo Morihara

Takeharu Nakada

Hiroki Sasame

Junji Suzuki

An image forming apparatus includes a controller and a transfer power supply portion configured to output a transfer voltage to a transfer portion so as to transfer a toner image onto a recording material. The transfer power supply portion superimposes a voltage output from a first power supply portion and a voltage output from a second power supply portion to output a superimposed voltage to the transfer portion. The first power supply portion includes a transformer including a primary coil and a secondary coil, and a rectifier circuit portion. The rectifier circuit portion includes a plurality of diodes and a plurality of capacitors. A capacitance of a predetermined capacitor to be charged by a half-wave rectified voltage of an AC voltage generated in the secondary coil is larger than a capacitance of a capacitor to be charged by a voltage higher than the half-wave rectified voltage.

Image forming apparatus including techniques and mechanisms to suppress occurrence of an image defect caused by a transfer step

A power supply apparatus including a transformer, a first rectifier smoothing unit, a separation unit, a second rectifier smoothing unit, a resistor, and a rectifier unit. The first rectifier smoothing unit is configured to rectify and smooth an alternating-current voltage generated in a secondary coil of the transformer. The separation unit configured to use the alternating-current voltage generated in the secondary coil of the transformer as an input and generate an alternating-current voltage, from which alternating-current components are separated, as an output. The second rectifier smoothing unit is configured to rectify and smooth the output of the separation unit. The resistor is connected to a line branched from a line that connects the separation unit to the second rectifier smoothing unit. The rectifier unit is connected in series between the resistor and a reference potential.

Power supply apparatus for outputting first and second voltages from one transformer and image forming apparatus including power supply apparatus

An image forming apparatus including: a charging member configured to charge a photosensitive member at a charging portion by a charging voltage in which an alternate-current voltage is superimposed on a direct-current voltage; a transfer member configured to transfer a toner image formed on the photosensitive member to a recording material at a transfer portion; and a controller configured to control the charging voltage, a predetermined area of the photosensitive member passing through the transfer portion during a trailing edge of the recording material passing through the transfer portion, wherein the controller controls a value of a peak-to-peak voltage of the alternate-current voltage when the predetermined area passes through the charging portion to be larger than a value of a peak-to-peak voltage when an area that becomes the image area other than the predetermined area passes through the charging portion.

Image forming apparatus

A power supply device includes first and second transformers, a first power source configured to output a first DC voltage from the first transformer, a second power source configured to output a second DC voltage from the second transformer, a first winding on a primary side of the first transformer, an auxiliary winding which is wound in the same winding direction as the first winding, and a voltage generator configured to be connected to the auxiliary winding and to generate a power supply voltage for driving a first controller of the first power source and a second controller of the second power source. When an AC voltage drops, control is performed such that the second controller stops prior to the first controller.

Power supply device and image forming apparatus including power supply device

The power supply apparatus includes the feedback winding of a transformer having a first winding, and a second winding whose number of turns is larger than that of the first winding. A voltage output from the transformer is detected. Based on the detected voltage, connection between a switch element and the first winding or the second winding is switched.

Growing community of inventors

Higashiyamato, Japan

Junichi Kubota