Canon Kabushiki Kaisha

Hirohisa Nakajima

Shinya Suzuki

Toshifumi Kakutani

Yousuke Hata

Takeyuki Suda

Toshiyuki Abe

Manabu Koseki

Kazumi Sato

Kazunori Miyake

Mitsuhiro Sugeta

Takayuki Iikura

Shuji Obata

Hiroyuki Eda

Sumito Tanaka

Jun Tomine

Kenichi Shibuya

Tetsuhiro Yoshimoto

Shota Soda

Toshihide Shima

Satoshi Ogawara

Masahiro Shinotsuka

Yohei Shiraki

An image forming apparatus includes a drum unit, a charging roller, a detector, a controller, a developing unit, and a notification unit. The drum unit includes an earth terminal connected to a housing of the image forming apparatus. The detector detects an amplitude of a first alternating-current voltage output to the charging roller. The controller controls so that an amplitude deviation between the first alternating-current voltage amplitude and an output target value of the first alternating-current voltage amplitude is made small. The developing unit develops an electrostatic latent image on the drum unit based on a second alternating-current voltage. The notification unit notifies an abnormality of the earth terminal based on the amplitude deviation in a first state where the first alternating-current voltage is output and the second alternating-current voltage is not output, and the amplitude deviation in a second state where the first and second alternating-current voltages are output.

Image forming apparatus configured to determine abnormality of drum unit earth terminal

A power supply apparatus includes: a power supply circuit configured to generate a bias voltage and output the bias voltage to a load, the power supply circuit being configured to output a determination signal and a detection current signal, the determination signal being binarized and representing a result obtained by comparing a voltage value according to the bias voltage with a threshold, the detection current signal indicating a current value of a load current flowing between the power supply circuit and the load, the load current flowing in response to outputting of the bias voltage; and a controller configured to control generation of the bias voltage generated by the power supply circuit, and determine a malfunction of the power supply circuit and an abnormality in the load, based on the determination signal and the detection current signal.

Power supply apparatus and image forming apparatus for determining malfunction or load abnormality

A control circuit determines that there is a failure in a power supply circuit in a case where a voltage detected by a voltage detection circuit when a constant-current control is performed is greater than a first predetermined value and a voltage detected by the voltage detection circuit when the first predetermined value is set as the target voltage in the constant-voltage control is greater than a second predetermined value greater than the first predetermined value and determine that there is an error in a load in a case where the voltage detected by the voltage detection circuit when the constant-current control is performed is greater than the first predetermined value and the voltage detected by the voltage detection circuit when the first predetermined value is set as the target voltage in the constant-voltage control is not greater than the second predetermined value.

Distinction of causes of errors in image forming apparatus

A bias output apparatus includes: a plurality of voltage output circuits, each configured to output a bias voltage to be supplied to a load and a determination voltage generated based on the bias voltage; a determination circuit configured to output a binary determination signal based on the determination voltage output by each of the plurality of voltage output circuits; and a controller configured to control the plurality of voltage output circuits and determine whether or not the plurality of voltage output circuits are operating normally based on the determination signal output by the determination circuit. The controller is further configured to determine that the plurality of voltage output circuits are operating normally if an output pattern of the determination signal is a predetermined first pattern while the controller is controlling the plurality of voltage output circuits to output bias voltages in order.

Bias output apparatus including a plurality of voltage output circuits, and image forming apparatus

An image forming apparatus which can control to turn on/off a light emitting element depending on a sheet state on a manual sheet tray is provided. The image forming apparatus includes the manual feed tray on which the sheet is placed. The image forming apparatus is configured to be switchable between normal power mode and power saving mode. In the normal power mode, normal power is supplied. In the power saving mode, less power is consumed as compared to the power consumed in the normal power mode. The image forming apparatus includes a manual sheet feeding sensor which detects presence/absence of the sheet on the manual feed tray. The image forming apparatus includes a sheet length sensor S and a sheet length sensor L which include the light emitting element and a light receiving element to detect approximate sheet length of sheet placed on the manual feed tray in a conveying direction.

Image forming apparatus

A high voltage generation apparatus that supplies a DC voltage to a load includes a current detection circuit that detects a DC flowing through the load. The current detection circuit includes an operational amplifier, and the current detection circuit detects the DC flowing through the load, as a voltage generated in a current detection resistor. The high voltage generation apparatus further includes a voltage detection circuit that detects a DC voltage supplied from a rectification circuit to the load. The current detection circuit includes a bypass circuit that causes a current to flow from a connection portion between the voltage detection circuit and a first input terminal of the operational amplifier to an output terminal of the operational amplifier in a case where the detected value of the DC that flows through the load drops below a predetermined value.

High voltage generation apparatus and image forming apparatus

An image forming apparatus includes: a first power source that supplies a charging voltage to a charger; a second power source that supplies a developing voltage to a developer; a first current detector that detects a current in the charger; a second current detector that detects a current in the developer; an OR circuit to which a first detection signal of the first current detector and a second detection signal of the second current detector are input; and a controller that determines an error related to the first power source or the photoreceptor or an error related to the second power source or the developer on the basis of an output signal of the OR circuit, which is output correspondingly to a level of the first detection signal or a level of the second detection signal.

Image forming apparatus including high voltage generating circuit

An image forming apparatus includes an image forming portion; a discharge portion configured to discharge a recording material on which an image is formed by the image forming portion, wherein a delivery conveyance portion having a power source circuit is mountable in a space adjacent to the image forming portion and configured to convey the recording material to a post-processing apparatus; a detection unit configured to detect a temperature; a cooling unit configured to cool the image forming portion; and a control unit configured to control, in a case where the delivery conveyance portion is mounted, rotation of the cooling unit based on the temperature detected by the detection unit in a standby state in which an image forming operation is not performed.

Image forming apparatus and image forming system

In an image forming apparatus including a plurality of image forming stations, on the basis of a density of a toner image formed in an upstream image forming station, an operation of a pre-exposure device in a downstream image forming station is controlled.

Image forming apparatus with pre-exposure member

An image forming apparatus including a motor for rotating a stirring member and a cleaner to which a driving force of the motor is transmitted via a transmission mechanism. In a buffer container of a toner replenishment device of a developing device, a gear connected to a restriction member for stirring toner in the buffer container and restricting toner from dropping into a toner conveying section and a cleaning member for cleaning the detection surface of a toner sensor are driven by a motor. A CPU controls a timing at which a clutch stops transmission of the driving force from the motor to the gear, based on a result of detection by a flag sensor that detects an amount of rotation of the gear, and a rotational speed of the motor.

Image forming apparatus that cleans detection surface of sensor for detecting developer accommodated in containing unit

A sheet feeding apparatus includes a stacking member, an optical sensor, a detected member, and a control unit. As an amount of sheets stacked on the stacking member decreases, the detected member moves from a first position in which optical sensor light is not interrupted, then once interrupts the light, and then moves to a second position in which the light is not interrupted. Information regarding an amount of sheets transmitted by the control unit, when stored information is about the detected member in the second position, is information notifying that an amount of sheets stacked on the stacking member is less than that of information regarding an amount of sheets stacked on the stacking member transmitted by the control unit when stored information is about the detected member is in the first position.

Sheet feeding apparatus and image forming apparatus

An image forming apparatus includes a waste toner container for containing toner recovered from a photosensitive drum and an intermediate transfer belt. The waste toner container has a stirring screw for conveying the toner in the waste toner container. The stirring screw is driven by a waste toner motor. A CPU determines whether the waste toner container is in need of replacement depending on a rotation speed or driving current of the waste toner motor. If the waste toner container is in need of replacement, the CPU displays such on a display unit to provide a notification to a user.

Image forming apparatus including determination of amount of waste toner

An image forming unit forms a toner image on an image carrier, and transfers the toner image to a recording medium. A voltage generation circuit generates a high voltage used for the image forming unit. A control circuit is connected to the voltage generation circuit via a cable, and controls the high voltage generated by the voltage generation circuit. A detection unit detects a current flowing in a load of the image forming unit to which the high voltage generated by the voltage generation circuit is applied. A determination unit determines an error in accordance with a current range in which the current detected by the detection unit falls. The current range is included among a plurality of current ranges that are in one-to-one correspondence with a plurality of errors.

Image forming apparatus that forms image on image carrier

An image forming apparatus including: a reading device; an operating portion; a light source; a rotary polygon mirror; a motor configured to rotate the rotary polygon mirror; and a motor control portion configured to start the motor to control the motor at a first rotation speed in response to a fact that a predetermined action is performed on one of the operating portion and the reading device in a stopped state of the rotary polygon mirror, and then to control the motor at a second rotation speed higher than the first rotation speed in response to an instruction to start image formation from the operating portion, the motor control portion being configured to control the motor at the second rotation speed, without controlling the motor at the first rotation speed, in response to a fact that the receiving portion receives image data before the motor reaches the first rotation speed.

Image forming apparatus with rotary polygon mirror speed control

An image forming apparatus configured to form an image on a recording medium, including: a process unit, which a high voltage is applied to, configured to perform an image forming process; a circuit board configured to generate the high voltage; a holding claw configured to hold the circuit board; a power feed member configured to apply the high voltage to the process unit, the power feed member having an elastic member electrically connected to an output portion of the circuit board from which the high voltage is output in a state in which the circuit board is held by the holding claw; and a silk-printed mark put on the circuit board, the silk-printed mark indicating a portion of the circuit board to be pressed by an operator in order to cause the circuit board to be held by the holding claw.

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Tsukubamirai, Japan

Hirohisa Nakajima