Canon Kabushiki Kaisha

Satoshi Ogawara

Yushi Oka

Takayuki Kawakami

Yoshitaka Yamazaki

Akihito Mori

Naoto Yamada

Hajime Motoyama

Hajime Kaji

Junichi Noguchi

Hirohisa Nakajima

Takashi Uehara

An image forming unit forms an image on a sheet. A first generation circuit generates, regarding a member involved in image formation in the image forming unit, a first signal relating to a first abnormality. A second generation circuit generates, regarding the member, a second signal that relates to a second abnormality different from the first abnormality, and whose feature in a time axis direction or a frequency axis direction is different from that of the first signal. A control circuit has a single port to which the first signal and the second signal are to be input. The control circuit identifies between the first signal and the second signal based on a feature of a signal input to the port.

Technique for transmitting signal indicating abnormality in image forming apparatus

An image forming apparatus includes an image bearing drum; a drum charging member, disposed at a charging position opposed to the drum, for applying the drum with a charging bias; a developing member for developing an electrostatic image formed on the drum with toner, with a developing bias; a transfer member for transferring a toner image from the drum onto a sheet, with a transfer bias; a transfer bias source for outputting the transfer bias; and a controller for effecting control to start raising of the transfer bias so as to correspond to a timing at which an area of the drum passing at a timing of starting of raising of the charging bias passes the transfer position and to complete the raising of the transfer bias so as to correspond to a timing at which an area of the drum passing at a timing of completion of raising of the charging bias passes the transfer position.

Image forming apparatus controlling charging bias and transfer bias

A first high-voltage power supply includes a first transformer configured to generate a voltage to be supplied to a first wire of a charger, and a second high-voltage power supply includes a second transformer configured to generate a voltage to be supplied to a second wire of the charger. The first and second high-voltage power supplies respectively drive the first and second transformers in accordance with pulse signals that are supplied from a CPU and that have the same frequency and phase. The first and second high-voltage power supplies respectively supply, to the first and second wires of the charger, voltages generated by driving the first and second transformers.

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

A printed circuit board, including: a substrate on which a component is mounted by solder; and a contact plate having a soldered portion soldered on the substrate, the contact plate being configured to be brought into contact with a contact of an apparatus to which the substrate is to be attached, wherein the soldered portion is soldered on a surface of the substrate opposite to a surface of the substrate on which the component is mounted, and wherein the contact plate has a suppressing portion configured to suppress an adhesion of a flux of the solder to a portion in which the contact plate is to be contacted by the contact, the suppressing portion making a flow path of the flux from the soldered portion to the portion longer than a straight-line distance from the soldered portion to the portion.

Printed circuit board and image forming apparatus

An image forming apparatus generates a PWM signal corresponding to input image data and controls a timing of a light source to emit a light beam based on the PWM signal in order to perform tone reproduction. The image forming apparatus includes a data processing unit configured to generate the PWM signal for one pixel based on image data for continuous two pixels in the image data. The data processing unit selects an origin of pulse growth in generation of the PWM signal for one pixel in accordance with the image data for the two pixels to generate the PWM signal.

Image forming apparatus and image forming method

An image formation device changes the rotational rate of a polygon motor, i.e. the main-scanning rate, and selects one of pulse width conversion tables when an image formation is performed multiple times on a single sheet of transfer paper. The changing of the main-scanning rate is for preventing inconsistent sizes between a first recorded image and a second recorded image caused by shrinkage of transfer paper. The pulse width conversion tables allow the pulse widths to be modulated.

Image formation device

An image forming apparatus which is capable of eliminating density irregularities of an image formed caused by potential irregularities of the photosensitive member when the drum is irradiated by a beam of constant luminous intensity. A laser driver irradiates a beam modulated based on an image signal onto a photosensitive member. A current controller variably controls a driving current for driving the laser driver. A PWM pulse width converter modulates a pulse width of the beam based on the image signal. A potential sensor measures the potential of the photosensitive member after the photosensitive member is irradiated by a beam having a predetermined luminous intensity. A selector causes the current controller to correct the driving current based on low frequency components of irregularities of the potential and changes a modulation coefficient used for modulating the pulse width based on high frequency components of the irregularities of the potential.

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Koshigaya, Japan

Satoshi Ogawara