Abstract: An image reading apparatus includes a transparent member on which an original is placed, a reading unit configured to read the original placed on the transparent member while moving in a first direction, and at least one processor configured to detect at least one edge of the original based on a reading result by the reading unit, wherein the at least one processor is configured to determine a candidate of a size of the original placed on the transparent member based on an edge, among the at least one detected edge, in the second direction orthogonal to the first direction, wherein the reading unit is configured to move in the first direction by a predetermined distance based on the candidate of the determined size.

Abstract: An image reading apparatus includes a transparent member on which an original is placed, a reading unit configured to read the original placed on the transparent member while moving in a first direction, and at least one processor configured to detect at least one edge of the original based on a reading result by the reading unit, wherein the at least one processor is configured to determine a candidate of a size of the original placed on the transparent member based on an edge, among the at least one detected edge, in the second direction orthogonal to the first direction, wherein the reading unit is configured to move in the first direction by a predetermined distance based on the candidate of the determined size.

Abstract: A transmitter transmits ultrasound to the conveyance path. A receiver receives the ultrasound. A double-feed detector detects whether or not double-feed of a plurality of sheets has occurred. A controller causes the transmitter to transmit ultrasound at a first burst interval when determining the threshold value, and causes the transmitter to transmit ultrasound at a second burst interval, which is shorter than the first burst interval, when detecting the double-feed of sheets. A double-feed detector determines a threshold value that enables distinction between double-feed and single-feed.

Abstract: A transmitter transmits ultrasound to the conveyance path. A receiver receives the ultrasound. A double-feed detector detects whether or not double-feed of a plurality of sheets has occurred. A controller causes the transmitter to transmit ultrasound at a first burst interval when determining the threshold value, and causes the transmitter to transmit ultrasound at a second burst interval, which is shorter than the first burst interval, when detecting the double-feed of sheets. A double-feed detector determines a threshold value that enables distinction between double-feed and single-feed.

Abstract: A sheet processing apparatus which is capable of reducing the frequency of switching a convey route. The sheet processing apparatus is provided with a switching unit that switches between a first position at which conveyed sheet is led to a first convey path, and a second position at which conveyed sheet is led to a second convey path. A buffering process of overlaying the conveyed sheet conveyed from a buffer path and another sheet subsequently conveyed by the conveyed unit is performed. The second convey path is used by the buffering process when the conveyed sheet to be received into the buffer path is ejected to the second stacking unit, and the first convey path is used by the buffering process when the conveyed sheet to be received into the buffer path is ejected to the first overlaying unit.

Abstract: A sheet processing apparatus capable of shortening time to align sheets. A first alignment member and a second alignment member are movable in a sheet width direction orthogonal to a sheet conveying direction, and align a sheet. A CPU controls the first and second alignment members to be moved in the sheet width direction. A skew sensor detects a skew amount and skew direction of the sheet. The CPU causes the first and second alignment members to be positioned at respective predetermined standby positions before the sheet is received between the first and second alignment member. Further, the CPU causes one of the first and second alignment members to be moved in a direction toward the sheet, based on the detected skew amount and skew direction, during conveyance of the sheet between the first and second alignment members.

Abstract: A sheet processing apparatus which is capable of reducing the frequency of switching a convey route. The sheet processing apparatus is provided with a switching unit that switches between a first position at which conveyed sheet is led to a first convey path, and a second position at which conveyed sheet is led to a second convey path. A buffering process of overlaying the conveyed sheet conveyed from a buffer path and another sheet subsequently conveyed by the conveyed unit is performed. The second convey path is used by the buffering process when the conveyed sheet to be received into the buffer path is ejected to the second stacking unit, and the first convey path is used by the buffering process when the conveyed sheet to be received into the buffer path is ejected to the first overlaying unit.

Abstract: A sheet processing apparatus that is capable of setting a sheet conveyance distance from a first detection to a second detection according to a sheet length. A sensor unit on which first and second sensors are arranged in a sheet width direction to detect a side end of a sheet in the sheet width direction. A moving unit moves the sensor unit in the sheet width direction. A setting unit sets up a second movement speed based on the sheet length obtained. A control unit controls the moving unit so as to move the sensor unit at a first movement speed, and so as to move the sensor unit at the second movement speed until the end section is detected by the second sensor after the side end is detected by the first sensor.

Abstract: A sheet processing apparatus capable of shortening time to align sheets. A first alignment member and a second alignment member are movable in a sheet width direction orthogonal to a sheet conveying direction, and align a sheet. A CPU controls the first and second alignment members to be moved in the sheet width direction. A skew sensor detects a skew amount and skew direction of the sheet. The CPU causes the first and second alignment members to be positioned at respective predetermined standby positions before the sheet is received between the first and second alignment member. Further, the CPU causes one of the first and second alignment members to be moved in a direction toward the sheet, based on the detected skew amount and skew direction, during conveyance of the sheet between the first and second alignment members.

Abstract: A sheet post-processing apparatus which is capable of shortening time wasted until actual start of punching and enhancing productivity. A drive unit causes a moving member which has a cam and reciprocates. A punching member is driven by a movement of the cam of the moving member and punches a sheet when the moving member moves forth and moves back. A determination unit determines a type of the sheet. A control unit controls, when a sheet to be punched is to be subjected to a punching process, the drive unit such that the moving member starts moving before conveyance of the sheet to be punched stops, and controls, when the sheet to be punched is to be subjected to the punching process, the drive unit such that timing with which the moving member starts moving is changed based on the determination by the determination unit.

Abstract: Provided are a sheet feeding device and an image forming apparatus that are capable of accurately detecting an abnormality of a feeding state without erroneously detecting when a trailing edge of a preceding sheet and a leading edge of a subsequent sheet are fed in an overlaid state. The sheet feeding device includes ultrasonic wave sensors 6 and 7 that detect an overlaid state of a preceding sheet Sa and a subsequent sheet Sb fed from feeding portions 51, 317 to 319 and a controller 1 that continuously performs a detection of the overlaid state of a sheet fed from the feeding portion at a predetermined number of detecting points along a sheet conveying direction at every predetermined time and determines a number of detecting points where detects. Based on the determined number of detecting points, the controller determines that the overlaid state is normal or abnormal.

Abstract: A sheet processing apparatus that is capable of setting a sheet conveyance distance from a first detection to a second detection according to a sheet length. A sensor unit on which first and second sensors are arranged in a sheet width direction to detect a side end of a sheet in the sheet width direction. A moving unit moves the sensor unit in the sheet width direction. A setting unit sets up a second movement speed based on the sheet length obtained. A control unit controls the moving unit so as to move the sensor unit at a first movement speed, and so as to move the sensor unit at the second movement speed until the end section is detected by the second sensor after the side end is detected by the first sensor.

Abstract: A sheet feeder which is capable of accurately detecting multi-feed of sheets even when the distance between sensors is changed. The sheet feeder includes a sheet container for holding a stack of sheets. Ultrasonic sensors for transmitting and receiving ultrasonic waves, respectively, are provided on a conveying path. The ultrasonic sensor as a transmitter transmits ultrasonic waves to a sheet being fed and conveyed. A reception circuit detects a level of ultrasonic waves received by the ultrasonic sensor as a receiver. The level of ultrasonic waves detected after lapse of a predetermined time from transmission of ultrasonic waves is compared with a predetermined threshold value to determine multi-feed of sheets. A distance between the ultrasonic sensors is detected, and at least one of the predetermined time period and the predetermined threshold value is corrected based on the detected distance between the sensors.

Abstract: Provided is a sheet feeding apparatus capable of reliably feeding thin sheets in a separated state and an image forming apparatus including the same. A floating preventing member which regulates an upward movement of an uppermost sheet floated by air is provided so as to be lifted and lowered between a tail end regulating plate regulating the position of the sheet above a tray and an adsorbing and conveying portion which conveys the uppermost sheet floated by the air blowing from a downstream air blowing portion. The adsorbing and conveying portion is moved to a predetermined regulating position higher than the height position of the uppermost sheet and lower than the feeding surface of the adsorbing and conveying portion before the sheet is floated, which suppresses the movement of the sheet toward the tail end side caused by the curling of the sheet due to the air.

Abstract: A sheet post-processing apparatus which is capable of shortening time wasted until actual start of punching and enhancing productivity. A drive unit causes a moving member which has a cam and reciprocates. A punching member is driven by a movement of the cam of the moving member and punches a sheet when the moving member moves forth and moves back. A determination unit determines a type of the sheet. A control unit controls, when a sheet to be punched is to be subjected to a punching process, the drive unit such that the moving member starts moving before conveyance of the sheet to be punched stops, and controls, when the sheet to be punched is to be subjected to the punching process, the drive unit such that timing with which the moving member starts moving is changed based on the determination by the determination unit.

Abstract: A sheet processing apparatus capable of high-speed and accurate detection of a lateral displacement and a skew of a sheet. A motor laterally shifts the sensors during sheet conveyance by a conveying motor, to determine first and second positions of the sheet lateral edge detected respectively by first and second sensors. A finisher controller determines a third position of the lateral edge of the sheet closer to a sheet trailing edge, based on the first and second positions and an amount of conveyance of the sheet from when the first position is detected to when the second position is detected. A lateral displacement of the sheet is corrected by laterally shifting the sheet according to the third position of the sheet lateral edge.

Abstract: A sheet feeder which is capable of accurately detecting multi-feed of sheets even when the distance between sensors is changed. The sheet feeder includes a sheet container for holding a stack of sheets. Ultrasonic sensors for transmitting and receiving ultrasonic waves, respectively, are provided on a conveying path. The ultrasonic sensor as a transmitter transmits ultrasonic waves to a sheet being fed and conveyed. A reception circuit detects a level of ultrasonic waves received by the ultrasonic sensor as a receiver. The level of ultrasonic waves detected after lapse of a predetermined time from transmission of ultrasonic waves is compared with a predetermined threshold value to determine multi-feed of sheets. A distance between the ultrasonic sensors is detected, and at least one of the predetermined time period and the predetermined threshold value is corrected based on the detected distance between the sensors.

Abstract: A sheet feeding device includes drawing and conveying a sheet, applying negative pressure for sheet suction via a suction opening, moving a shutter member between a closing position where the suction opening in an upstream side in a sheet feeding direction is partially closed and an open position where the suction opening is opened, and controlling the shutter member to follow a preceding sheet that is drawn onto the suction conveyance member to move to the downstream side in the feeding direction to close the suction opening, and return to an open position at a predetermined timing to draw the sheets onto the suction conveyance member in a state where an upstream edge of the preceding sheet in the feeding direction and a downstream edge of the subsequent sheet in the feeding direction are overlaid by a predetermined amount.

Abstract: A sheet feeding apparatus and an image forming apparatus are provided. When sheets are adsorbed to an adsorption conveyance belt, a suction shutter is switched from a block position to block a negative pressure to an adsorption position to adsorb the sheets by the negative pressure. When the sheets conveyed in an overlapping manner reaches a predetermined number and the next sheet is adsorbed, the timing to switch the suction shutter to the adsorption position is delayed compared to the timing at which a preceding sheet adsorbed in advance and a subsequent sheet overlap.

Abstract: A sheet feeding apparatus and an image forming apparatus are provided. Timing when a subsequent sheet is adsorbed by an adsorbing and conveying mechanism of a sheet feeding device which adsorbs and conveys sheets blown up by air blowing is controlled, and the subsequent sheet is conveyed while being overlapped partially at an overlapping amount with a preceding sheet Sa adsorbed by the adsorbing and conveying mechanism earlier regardless of the size, basis weight, and kind of sheets.