Canon Kabushiki Kaisha

Naoki Kanno

Tadashi Fukumuro

Hideo Nanataki

Atsushi Nakamoto

Toshihiko Takayama

Ryuichi Yoshizawa

Taro Minobe

Masayuki Sakai

Keizo Kojima

An image forming apparatus includes a stacker, a feeding roller, an image forming unit, a detector detecting a recording material, and a controller controlling a feed interval between recording materials continuously fed by the feeding roller. The controller sets the feed interval between a first recording material precedently fed and a second recording material subsequent to the first recording material to a first feed interval based on an image signal. In a case that the detector does not detect a trailing end of the first recording material with respect to a feeding direction after detecting the first recording material until a predetermined time elapses, the controller sets the feed interval to a second feed interval longer than the first interval and determines a timing of image forming on the second recording material by the image forming unit based on the second feed interval.

Image forming apparatus with setting feed interval between recording materials based on received image signal

An image forming apparatus includes a detection unit to detect recording material fed from a stacking unit, a determination unit, a count unit, and a control unit. The determination unit determines that a feeding failure has occurred when the detection unit does not detect the recording material until elapse of a predetermined period. The count unit counts a number of times the feeding operation is performed for a single sheet of the recording material. When the counted number of feeding operation performance times by when the feeding failure has occurred is smaller than a threshold, the control unit restarts the feeding operation that has been stopped without waiting for a user's operation. When the counted number of feeding operation performance times by when the feeding failure has occurred is at least equal to the threshold, the control unit waits for the user's operation while the feeding operation is stopped.

Image forming apparatus that controls feeding operation

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.

Image forming apparatus

The image forming apparatus includes a control unit for converting image information into an image signal and output the image signal with reference to a timing signal, a sheet feeding control unit for feeding a recording material, an image forming unit for forming the image on a photosensitive drum based on the image signal output from the control unit, a transmission unit for transmitting a length of the image corresponding to a length of an output period of the image signal, an automatic sheet length detection mechanism for acquiring a length of the recording material in a conveyance direction thereof, and an image control unit for controlling a time interval at which the timing signal is output based on the size of the image and the size of the recording material.

Image forming apparatus with image timing signal adjustment

An image forming apparatus includes image bearing members, an intermediate transfer member, a transfer unit, a control unit, and image forming units respectively corresponding to the image bearing members and each configured to form and transfer an image to the intermediate transfer member, which is then transferred to the conveyed recording material. Image patterns on the intermediate transfer member are detected for positional deviation detection. In a first mode, timing of image formation is determined using a first reference. In a second mode, timing of image formation is determined using a second reference. Based on timings at which formed image patterns are detected, the control unit, in the second mode, corrects timing of image formation performed by a second image forming unit or corrects timing at which the recording material is conveyed to the transfer unit.

Image forming apparatus to correct timing of image formation

A plurality of development units includes at least a first development unit and a second development unit, and a plurality of photosensitive members includes at least a first photosensitive member corresponding to the first development unit and a second photosensitive member corresponding to the second development unit. After shifting the first development unit and the first photosensitive member into a contact state and shifting the second development state and the second photosensitive member into a contact state, a control unit controls a timing at which the first development unit develops an electrostatic latent image, based on a contact timing at which the second development unit and the second photosensitive member are shifted into a contact state.

Image forming apparatus including a contact-separation mechanism

The image forming apparatus includes a plate movable up and down, a control cam that moves the plate up and down, a stepping motor that derives the control cam, a sheet feeding roller that contacts the sheet on the plate moved up by the control cam to feed the sheet held in contact with the feeding unit through rotation caused by drive from the stepping motor, and a control unit that controls the stepping motor. The control unit rotates the stepping motor at a first speed so that the control cam moves the plate up. After the sheet feeding roller is rotated, when the sheet feeding roller is stopped to stop the stepping motor, the control unit changes the rotational speed of the stepping motor from the first speed to a second speed.

Provided is an image forming apparatus for driving a cassette pickup roller () and a registration roller () by using the same driving source, in which a conveyance control portion () starts conveyance speed control for a subsequent sheet, which is fed from a sheet feeding position subsequently to a preceding sheet fed therefrom earlier, when it is determined that a trailing edge of the preceding sheet has passed through the registration roller ().

A control unit changes the polarity of a potential of an intermediate transfer member in a primary transfer portion by changing the polarity of voltage to be applied to a secondary transfer member, and applies first voltage in a first step of forming an image on a recording material by transferring a toner image. A detection device detects the presence/absence of the recording material at a timing when a rear end of the toner image reaches a second position which is upstream of a secondary transfer portion on a conveyance path of the toner image. The control unit determines a timing to switch the voltage to be applied to the secondary transfer member from the first voltage to second voltage having polarity opposite to that of the first voltage, based on the detection result by the detection device.

An image forming apparatus includes a switching unit that can switch polarities of potentials of an intermediate transfer member generated at a primary transfer part and a secondary transfer part in synchronization, and a control unit that executes adjustment processing in which a potential having a polarity opposite to the polarity upon the transfer is generated at least one of the primary transfer part and the secondary transfer part, in which the control unit controls the switching unit in a manner that, in a case where the adjustment processing is performed in a course of continuous image formation on a plurality of transfer materials conveyed to the secondary transfer part, a timing for generating the potential having the opposite polarity corresponds to a timing at which toner images are not transferred at both of the primary transfer part and the secondary transfer part.

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Fujisawa, Japan

Naoki Kanno