Abstract: An image formation apparatus to form an image on a sheet having a width direction includes a separation and feed roller pair having a feed roller, a conveyance roller pair having a driving roller, and a pair of conveyance guides having inner and outer guides. A part of the inner guide overhangs toward an outer guide side from an external common tangent of the feed roller and the driving roller. Points of intersection with the feed roller on the external common tangent are designated as first intersection points and points of intersection with the driving roller on the external common tangent are designated as second intersection points. When ends of the feed and driving rollers serve as vertexes, a guide surface of the inner guide is linearly continuous in the width direction in an inner region on the guide surface of the inner guide formed by connecting the vertexes.

Abstract: An image formation apparatus to form an image on a sheet having a width direction includes a separation and feed roller pair having a feed roller, a conveyance roller pair having a driving roller, and a pair of conveyance guides having inner and outer guides. A part of the inner guide overhangs toward an outer guide side from an external common tangent of the feed roller and the driving roller. Points of intersection with the feed roller on the external common tangent are designated as first intersection points and points of intersection with the driving roller on the external common tangent are designated as second intersection points. When ends of the feed and driving rollers serve as vertexes, a guide surface of the inner guide is linearly continuous in the width direction in an inner region on the guide surface of the inner guide formed by connecting the vertexes.

Abstract: An image forming apparatus includes a control unit and an attachment detection unit to detect attachment of a cassette having a stacking portion that may be lifted by a motor. The control unit drives the motor to start lifting the stacking portion when cassette attachment is detected and stops when the stacked uppermost sheet is detected at a sheet feed position, at which time the presence or absence of the stored sheet is determined based on a detection signal output by a sheet presence/absence detection unit. In a case where there is no change in the detection signal output from the sheet presence/absence detection unit when the attachment of the cassette is detected, the control unit determines that a failure of the sheet presence/absence detection flag occurred.

Abstract: An image forming apparatus includes a control unit and an attachment detection unit to detect attachment of a cassette having a stacking portion that may be lifted by a motor. The control unit drives the motor to start lifting the stacking portion when cassette attachment is detected and stops when the stacked uppermost sheet is detected at a sheet feed position, at which time the presence or absence of the stored sheet is determined based on a detection signal output by a sheet presence/absence detection unit. In a case where there is no change in the detection signal output from the sheet presence/absence detection unit when the attachment of the cassette is detected, the control unit determines that a failure of the sheet presence/absence detection flag occurred.

Abstract: A sheet feeding apparatus, including: a containing portion removable from the sheet feeding apparatus and including a tray; a pickup roller; a support portion configured to fall the pickup roller on the sheet stacked on the tray when a far-side end of the containing portion reaches a predetermined position; a detector configured to detect the containing portion; a motor configured to drive the pickup roller; and a controller configured to control an operation of feeding the sheet by the pickup roller, wherein, during a period in which the pickup roller is driven with the detector detecting the containing portion, the controller allows the operation when an amount of a load torque applied to a rotor of the motor is equal to or larger than a predetermined value and inhibits the operation when the amount of the load torque is smaller than the predetermined value.

Abstract: The present invention is for separating upper and lower sheets. The sheet feeder includes a feed roller that conveys the sheet fed by a pickup roller in a sheet feeding direction and a retard roller rotated in a sheet feeding direction at a rotational velocity faster than that of the feed roller by interposing a torque limiter. Meanwhile, the retard roller is rotated at a velocity equal to that of the feed roller when a single sheet is nipped in the roller nip portion. The sheet feeder further includes a controller that performs control such that, when double sheet feeding occurs by the pickup roller, the sheet of the retard roller side projects ahead of the sheet of the feed roller side in the sheet feeding direction by virtue of the torque limiter, and then, the retard roller is rotated in a direction opposite to the sheet feeding direction.

Abstract: Provided are a sheet feeding device with improved separating/feeding performance. The sheet feeding device includes a sheet storage portion, a pickup roller which feeds the sheet, a driving motor which rotates the pickup roller, a feed roller and a separating roller which separate and feed the sheet, and a drive transmission mechanism which when the pickup roller abuts on the surface of the sheet accommodated in the sheet storage portion to feed the sheet, allows the pickup roller to perform intermittent rotation that alternately perform rotation and stop twice or more while one sheet is fed. The drive transmission mechanism is connected to the driving motor and includes an input gear having a plurality of protrusions and a regulating portion which is engaged with the protrusions of the input gear to regulate the rotation of the input gear.

Abstract: The present invention is for separating upper and lower sheets. The sheet feeder includes a feed roller that conveys the sheet fed by a pickup roller in a sheet feeding direction and a retard roller rotated in a sheet feeding direction at a rotational velocity faster than that of the feed roller by interposing a torque limiter. Meanwhile, the retard roller is rotated at a velocity equal to that of the feed roller when a single sheet is nipped in the roller nip portion. The sheet feeder further includes a controller that performs control such that, when double sheet feeding occurs by the pickup roller, the sheet of the retard roller side projects ahead of the sheet of the feed roller side in the sheet feeding direction by virtue of the torque limiter, and then, the retard roller is rotated in a direction opposite to the sheet feeding direction.