A sheet feeding device includes a pickup roller, a lifting/lowering mechanism, and a driver device. The lifting/lowering mechanism includes a restricting member that releasably restricts the pickup roller from being lowered from a lifted position of the pickup roller at the lifted position. In the sheet feeding device, the driver device drives the lifting/lowering mechanism so that the pickup roller is lowered from the lifted position of the pickup roller, and a drive suspend operation is performed in which the driving of the lifting/lowering mechanism by driver device is suspended after a predetermined time during which the pickup roller does not contact a sheet loading tray or a sheet on the sheet loading tray elapses from a time point when the pickup roller is released from being restricted by the restricting member at the lifted position.

An image forming apparatus comprising includes an image carrying member including a movable surface to include a toner image; a transfer roller to form a transfer nip between the transfer roller and the movable surface of the image carrying member, to move position in a direction in correspondence to a thickness of a print medium to intersect a direction of introduction of the print medium into the transfer nip, and to receive a transfer bias voltage to transfer the toner image from the movable surface of the image carrying member to the print medium; and a movement guide structure to guide the print medium toward the transfer nip, and to move in synchronization with the movement of the position of the transfer roller to change a gap between an end of the movement guide structure facing the image carrying member and the image carrying member.

An image forming apparatus comprising includes an image carrying member including a movable surface to include a toner image; a transfer roller to form a transfer nip between the transfer roller and the movable surface of the image carrying member, to move position in a direction in correspondence to a thickness of a print medium to intersect a direction of introduction of the print medium into the transfer nip, and to receive a transfer bias voltage to transfer the toner image from the movable surface of the image carrying member to the print medium; and a movement guide structure to guide the print medium toward the transfer nip, and to move in synchronization with the movement of the position of the transfer roller to change a gap between an end of the movement guide structure facing the image carrying member and the image carrying member.

A switching device for switching transport directions of a recording medium includes a switching member and at least one rotation stopper. The switching member is configured to switch transport paths of the recording medium. The at least one rotation stopper is configured to hit the switching member to stop rotation of the switching member. The at least one rotation stopper is disposed asymmetrically in a direction perpendicular to a transport direction in which the switching member transports the recording medium.

A sheet feeding device includes a pickup roller, a lifting/lowering mechanism, and a driver device. The lifting/lowering mechanism includes a restricting member that releasably restricts the pickup roller from being lowered from a lifted position of the pickup roller at the lifted position. In the sheet feeding device, the driver device drives the lifting/lowering mechanism so that the pickup roller is lowered from the lifted position of the pickup roller, and a drive suspend operation is performed in which the driving of the lifting/lowering mechanism by driver device is suspended after a predetermined time during which the pickup roller does not contact a sheet loading tray or a sheet on the sheet loading tray elapses from a time point when the pickup roller is released from being restricted by the restricting member at the lifted position.

A switching device for switching transport directions of a recording medium includes a switching member and at least one rotation stopper. The switching member is configured to switch transport paths of the recording medium. The at least one rotation stopper is configured to hit the switching member to stop rotation of the switching member. The at least one rotation stopper is disposed asymmetrically in a direction perpendicular to a transport direction in which the switching member transports the recording medium.

A sheet feeding device includes a lift plate, a feeding portion, a lifting member lifting the lift plate, a motor coupled to a pivot shaft serving as the pivot fulcrum of the lifting member, a control portion, and an encoder outputting a pulse signal according to the rotation of the pivot shaft. The encoder includes a rotary member and an optical sensor. The control portion recognizes the remaining quantity of sheets on the lift plate based on the count value of the pulse signal. When the motor stops being driven, the control portion thereafter does not count the pulse signal until a predetermined period elapses.

The present disclosure provides a drive transmission apparatus capable of reducing vibration of rotating member. The apparatus includes a shaft, a pin, and a rotating member. The rotating member is engaged with the shaft by the pin and rotates with the shaft. A protruded portion is provided on one of an outer circumferential surface of the shaft and an inner circumferential surface of the rotating member. The rotating member is attached to the shaft with the protruded portion in pressure contact with another one of the outer circumferential surface of the shaft and the inner circumferential surface of the rotating member, so that swinging of the rotating member around the pin is restricted.

The present invention provides a non-contact vibration suppression device comprising a first ultrasonic vibration unit and a second ultrasonic vibration unit, the device being characterized in that the first ultrasonic vibration unit and the second ultrasonic vibration unit are installed to face each other while being spaced from each other such that an object can be interposed therebetween, the first ultrasonic vibration unit and the second ultrasonic vibration unit generate ultrasonic vibrations, respectively, and apply repulsive forces, which result from the ultrasonic vibrations, to the object such that the object is constrained with no contact between the first ultrasonic vibration unit and the second ultrasonic vibration unit, thereby suppressing vibration of the object. In addition, the present invention provides an object processing method characterized by comprising the steps of: suppressing vibration of the object using the non-contact vibration suppression device; and processing the object, vibration of which has been suppressed.

The present disclosure provides a drive transmission apparatus capable of reducing vibration of rotating member. The apparatus includes a shaft, a pin, and a rotating member. The rotating member is engaged with the shaft by the pin and rotates with the shaft. A protruded portion is provided on one of an outer circumferential surface of the shaft and an inner circumferential surface of the rotating member. The rotating member is attached to the shaft with the protruded portion in pressure contact with another one of the outer circumferential surface of the shaft and the inner circumferential surface of the rotating member, so that swinging of the rotating member around the pin is restricted.