Canon Kabushiki Kaisha

Keizo Kojima

Keisuke Samejima

Takashi Odate

Toshihiko Takayama

Ryo Matsumura

Taro Minobe

Seiji Saito

Hideo Nanataki

Atsushi Nakamoto

Keisuke Ishizumi

Shingo Ito

Masaru Ohno

Shohei Ishio

Naoki Kanno

Atsushi Ohno

An image forming apparatus includes a sheet feeding portion, a detecting portion, and a controller. The controller sets a state of the detecting portion at a first monitoring state in which a detection result of the detecting portion is acquired to detect presence or absence of the recording material by supplying the electric power to the detecting portion in a first cyclic period. In case that the detection result of the detecting portion changes in the first monitoring state, the controller switches the state of the detecting portion to a second monitoring state in which a detection result of the detecting portion is acquired by supplying the electric power to the detecting portion in a second cyclic period shorter than the first cyclic period.

Image forming apparatus

A control circuit executes voltage adjustment processing of adjusting a voltage output from a transfer power source so that a current detected by a detection circuit becomes a predetermined current value. The voltage adjustment processing is executed before a toner image is transferred from at least one of a first image bearing member and a second image bearing member to an intermediate transfer belt. A processor determines whether the second transfer member is in a state of contact or is in a state of separation on the basis of behavior of the current detected by the detection circuit in a period in which the control circuit is executing the voltage adjustment processing.

Image forming apparatus that determines whether or not plurality of rotating bodies are in state of contact

The voltage detection apparatus includes a reference power supply that outputs a predetermined voltage; a voltage conversion unit that converts detected information into a voltage; and a switching unit that switches between a first state in which the predetermined voltage is supplied from the reference power supply to the primary side of a transmission unit, and a second state in which the voltage resulting from the conversion is supplied from the voltage conversion unit to the primary side of the transmission unit. The switching unit switches to the first state, in which a correction value for correcting a digital value is acquired. The switching unit switches to the second state, in which a voltage value acquired based on the digital value is corrected with the correction value to acquire a corrected voltage value.

Voltage detection apparatus and image forming apparatus

A controller can select and execute a full color mode of performing image formation in a first state in which each primary transfer member is in contact with an intermediate transfer belt, and a monochrome mode of performing image formation in a second state in which only a primary transfer member is in contact with the intermediate transfer belt. The controller determines which state of the first state and the second state is formed, based on a detection result obtained by a current detection circuit when a photosensitive drum is charged by a charging roller, and voltage is applied to the primary transfer member from a primary transfer power source.

The power supply apparatus having two switching elements connected to a primary winding of a transformer includes an adjustment unit for adjusting a voltage and supplying the voltage to a control unit. This voltage results from application of a voltage induced in an auxiliary winding while current is flowing in a predetermined direction with respect to the auxiliary winding as a result of the first switching element turned on and the second switching element turned off, and a voltage induced in the auxiliary winding while current is flowing in the direction opposite to the predetermined direction with respect to the auxiliary winding as a result of the first switching element turned off and the second switching element turned on.

Power supply apparatus and image forming apparatus

An image forming apparatus includes a voltage adjustment portion having a voltage adjustment member connected to a contact member contacting an endless belt, the voltage adjustment portion changing a current flowing from a current supply member contacting the belt at a position different from a position, at which an image bearing member contacts the belt with respect to a rotating direction of the belt, to the voltage adjustment member via the belt according to a control signal input from a control portion outputting a control signal, thereby changing a size of a transfer potential to transfer a toner image borne by the image bearing member onto the belt at a part at which the belt contacts the image bearing member.

Image forming apparatus with voltage adjustment member

A power supply device including a transformer having a primary winding and a secondary winding, and a switching element connected to the primary winding configured to drive the switching element to output voltage from the secondary winding includes a control unit configured to drive the switching element such that the switching element is turned on and, in which, in a case where the control unit performs an intermittent drive operation which repeats a period for which the switching element is driven and a period for which the drive of the switching element is stopped, in which the control unit drives the switching element such that the switching element is turned off before the voltage according to the current flowing to the primary winding reaches the voltage output from the secondary winding in the period for which the switching element is driven.

Switching power supply and image forming apparatus equipped with switching power supply

A power supply apparatus includes a transformer and a switching unit that causes two switching elements connected in series to drive the primary winding of the transformer. A detection unit detects current flowing on the primary side of the transformer and outputs a voltage corresponding to the detected current. A correction unit corrects the voltage output from the detection unit into a voltage proportional to a variation of an input voltage input into the primary side of the transformer A nonlinear correction unit corrects the corrected voltage corrected by the correction unit to be nonlinear independently of variation in the input voltage.

A power supply apparatus determines that an input AC voltage has reached a voltage at which a power supply control IC can start operating, based on the voltage at an auxiliary winding of a transformer included in a first converter. Note that since the first converter operates so as to maintain a constant voltage at the auxiliary winding, whether the input AC voltage has fallen to an operation lower limit voltage or lower cannot be detected by only monitoring the voltage at the auxiliary winding. The power supply apparatus monitors a second voltage that is proportional to the input AC voltage is generated from the voltage being applied to the primary side of a second converter. Accordingly, the power supply control IC starts and stops operating in accordance with the input AC voltage.

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Yokohama, Japan

Keizo Kojima