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: 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: 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: A sheet feeder which feeds a sheet in a sheet storage case includes a sheet storage case in which a sheet is stored, a dehumidifier which dehumidifies air, an air tank in which air dehumidified by the dehumidifier is stored, shutters and which bring the air tank and the sheet storage case into communication and out of communication, and fans and which send air between the air tank and the sheet storage case. The shutters and the fans are operated in accordance with humidity in the sheet storage case.

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.

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: A loosening fan provided in an air blowing unit blows at sheets stacked on a tray to loosen the sheets. When, during a sheet feeding operation, a multi-feed detection unit detects a multi-feed condition, the loosening fan is controlled such that an air pressure that enables the sheets to be loosened is obtainable. Therefore, the occurrence of multi-feed conditions can be reduced.

Abstract: A loosening fan provided in an air blowing unit blows at sheets stacked on a tray to loosen the sheets. When, during a sheet feeding operation, a multi-feed detection unit detects a multi-feed condition, the loosening fan is controlled such that an air pressure that enables the sheets to be loosened is obtainable. Therefore, the occurrence of multi-feed conditions can be reduced.

Abstract: An image reading apparatus reads an image from a document being simultaneously fed by the apparatus. A document feeder unit feeds the document on a original plate. A first image reading unit reads an image from the fed document at a first document-read position on the original plate. A second image reading unit reads an image from the fed document at a second document-read position located at a predetermined distance from the first document-read position in a document feeding direction. An abnormal pixel detection unit detects abnormal pixels resulting from rubbish moved between the first document-read position and second document-read position on the original plate together with the document.

Abstract: There is provided an image reading apparatus for acquiring a read signal of an image by receiving and photoelectrically converting a light reflected from a document. The location of an alien substance on an original plate is detected based on a reflected light received by a light receiving unit adapted to receive a light reflected from a document. When an alien substance is detected, an illumination unit selectively illuminates the location in which the alien substance has been detected. Also, a message which prompts cleaning of the alien substance is displayed. A method of displaying the alien substance location are also provided. Thereby, the image reading apparatus of the present invention can assists a user in cleaning the alien substance such as a dust or dirt on the original plate.

Abstract: An image forming system capable of controlling a handover timing of sheets between an image forming apparatus and a sheet feeding apparatus at 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: To determine an area of a whiteout applied on an original, an area in which an output of a CCD is saturated is determined to be a correction trace area based on image read in an exposure-down having exposure reduced from a normal exposure amount. Correction trace information obtained by determining and detecting the correction trace area is correlated with image data to be stored as attribute information of an image file. When the image file is displayed on a PC screen, the correction trace area of an original image read based on position information of a correction trace contained in the attribute information transferred from an image reading apparatus is highlighted.

Abstract: An image forming apparatus has a sheet feeding apparatus which separates and feed a sheet one by one using a loosening fan which blows air from an air blowing portion for loosening the sheet on a tray. The rotating speed of the sheet loosening fan is adjusted while the sheet supported by the tray is not located in front of a position where the air is blown from the air blowing portion.

Abstract: A sheet feeding apparatus includes a sheet feeding unit configured to suction a stored sheet with a negative pressure to feed the suctioned sheet, a suction duct connected to the sheet feeding unit, a suction fan configured to generate a negative pressure in the suction duct, a shutter disposed in the suction duct and configured to allow and shut off communication between the sheet feeding unit and the suction fan, and a communicating mechanism configured to cause a space in the suction duct between the shutter and the sheet feeding unit to communicate with an outside of the suction duct. The communicating mechanism is configured to cause the space in the suction duct to communicate with the outside of the suction duct according to the shutter shutting off communication between the sheet feeding unit and the suction fan.