Abstract: An image forming system which is capable of, when a manual stapling process is to be carried out on sheets, reducing waiting time for a user and decreasing power consumption. The image forming system has an image forming apparatus, which forms images on sheets, and a sheet post-processing apparatus. When the sheet post-processing apparatus is to shift into a power-saving state, a movable stapler is moved to a manual stapling position. When it is detected that sheets have been set into a sheet setting unit in a state in which the image forming apparatus and the sheet post-processing apparatus have shifted into the power-saving state, the image forming apparatus is held in the power-saving state, and the sheet post-processing apparatus is returned from the power-saving state.

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 material binding apparatus capable of shortening a user's waiting time required to bind sheets through a manual operation with a movable stapler. A CPU (162) of a sheet material binding apparatus (50) monitors whether or not an image forming apparatus (1) can execute image formation processing. When the image forming apparatus (1) can execute the image formation processing, the movable stapler is arranged at a standby position close to the image forming apparatus (1). When the image forming apparatus (1) cannot execute the image formation processing, on the other hand, the movable stapler is arranged at a position for performing the manual operation, to thereby bind the sheets through the manual operation immediately.

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: Provided are a high-quality sheet feeding apparatus which can detect multifeeding of sheets in a wide range of the sheet conveying direction and realize a stable conveying state, and an image forming apparatus therewith. A CPU controls a multifeeding detection sensor to detect multifeeding of sheets at a plurality of transmission points P1 to P5 of the multifeeding detection sensor. This CPU sets a plurality of transmission points across the front end and rear end of a sheet moving in the sheet conveying direction, based on size information of the sheet read from a storage portion and the timing of detection passing of the sheet in a horizontal path first sensor. This enables detection of multifeeding across the front end and rear end of a preceding sheet in the sheet conveying direction, and also enables detection of unseparated multifeeding that a subsequent sheet follows overlapping the preceding sheet.

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.

Abstract: An image forming system controls a handover timing of sheets between an image forming apparatus and a sheet feeding apparatus with high precision. A transmission path transmits information between the image forming apparatus and the sheet feeding apparatus. A signal line transmits a handover signal output from the image forming apparatus to the sheet feeding apparatus. A first control unit transmits the handover signal to the sheet feeding apparatus after transmitting a feeding start request to the sheet feeding apparatus. A second control unit controls the sheet feeding apparatus to convey the sheet to a predetermined position in the sheet feeding apparatus in accordance with a reception of the feeding start request and of conveying the sheet at the predetermined position to the image forming apparatus in accordance with a reception of the handover signal.

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 feeding apparatus and an image forming apparatus are provided which can reduce the variability of overlapped portions when feeding sheets in an overlapping manner. 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: An image forming apparatus capable of accurately detecting a thickness of various sheets. A CPU of the image forming apparatus sets the degree of amplification to a large value, if a sheet basis weight is equal to or less than a threshold value, and sets the degree of amplification to a small value, if the sheet basis weight is larger than the threshold value. One of magnetic sensors, which are disposed facing respective ones of magnets mounted to a displacement member of a sheet thickness detection device of the image forming apparatus, is selected according to the set degree of amplification. When a sheet passes through a detection part of the displacement member, a displacement of the detection part amplified through the displacement member is detected by the selected sensor and a sheet thickness is detected based on an output of the sensor.

Abstract: A sheet thickness detection device capable of accurately detecting a thickness of sheets of various types. In a case that information about sheets stored in a sheet feed unit is set by a user through an operation unit or through an external host PC, a CPU of the sheet thickness detection device sets a pressure changeover solenoid to ON to obtain a strong nip pressure between a detection roller and a fixed roller, if a sheet basis weight specified in the information about sheets is larger than a predetermined value, and sets the pressure changeover solenoid to OFF to obtain a weak nip pressure, if the sheet basis weight specified in the information about sheets is equal to or less than the predetermined value.

Abstract: A sheet feeding apparatus includes a back end detecting sensor which detects a back end side in a conveying direction of the topmost sheet stacked on the sheet tray, a front end detecting sensor which detects a front end side in the conveying direction of the topmost sheet, and a CPU. The CPU disables start of a sheet feeding operation of a feeding unit in a case where the back end detecting sensor and the front end detecting sensor do not detect the sheet when the sheet tray is lifted toward the feeding unit and then stopped in a predetermined position. Accordingly, a state that a feeding failure is possibly caused is detected before feeding the sheets so as to eliminate the wasteful feeding operation.

Abstract: An upper air blowing portion that blows air from above a sheet held by a tray is provided above the portion between a trailing end restricting plate and an absorption conveyance portion. A controlling portion drives the upper air blowing portion so as to restrict the movement of the sheet in the direction reverse to the sheet feeding direction, when the sheet held on the tray moves in the direction reverse to the sheet feeding direction with the air blown by the air blowing portion.

Abstract: An original reader which is capable of continuously performing a reading operation for reading images from originals without causing degradation of the quality of the read images, even when a light emitter of an illumination unit or a driving circuit for the light emitter fails. An original illuminating lamp including two LED circuit boards each having eight LED blocks linearly arranged in the main scanning direction of an original illuminates the original. An image sensor reads an image from the original illuminated by the original illuminating lamp. When it is detected that at least one of the LED blocks does not emit light, a CPU performs control such that the light amount of an LED block opposed to the LED block emitting no light is increased to be larger than when it is not detected that at least one of the LED blocks does not emit light.

Abstract: The present invention provides a sheet feeding apparatus and an image forming apparatus enabling high-accuracy and stable sheet overlapping conveyance regardless of the size, basis weight, and kind of sheets. Timing when a subsequent sheet Sb is adsorbed by an adsorbing and conveying mechanism 151 of a sheet feeding device 312 which adsorbs and conveys sheets blown up by air blowing is controlled, and the subsequent sheet Sb is conveyed while being overlapped partially at an overlapping amount with a preceding sheet Sa adsorbed by the adsorbing and conveying mechanism 151 earlier regardless of the size, basis weight, and kind of sheets.

Abstract: An upper air blowing portion that blows air from above a sheet held by a tray is provided above the portion between a trailing end restricting plate and an absorption conveyance portion. A controlling portion drives the upper air blowing portion so as to restrict the movement of the sheet in the direction reverse to the sheet feeding direction, when the sheet held on the tray moves in the direction reverse to the sheet feeding direction with the air blown by the air blowing portion.

Abstract: Provided are a high-quality sheet feeding apparatus which can detect multifeeding of sheets in a wide range of the sheet conveying direction and realize a stable conveying state, and an image forming apparatus therewith. A CPU controls a multifeeding detection sensor to detect multifeeding of sheets at a plurality of transmission points P1 to P5 of the multifeeding detection sensor. This CPU sets a plurality of transmission points across the front end and rear end of a sheet moving in the sheet conveying direction, based on size information of the sheet read from a storage portion and the timing of detection passing of the sheet in a horizontal path first sensor. This enables detection of multifeeding across the front end and rear end of a preceding sheet in the sheet conveying direction, and also enables detection of unseparated multifeeding that a subsequent sheet follows overlapping the preceding sheet.