Patent application number | Description | Published |
20090066010 | SHEET FEEDER AND IMAGE FORMING APPARATUS - 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. | 03-12-2009 |
20100066012 | IMAGE FORMING SYSTEM, IMAGE FORMING APPARATUS, AND SHEET FEEDING APPARATUS - 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. | 03-18-2010 |
20100314825 | IMAGE FORMING APPARATUS - 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. | 12-16-2010 |
20110169211 | SHEET FEEDING APPARATUS AND IMAGE FORMING APPARATUS - 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. | 07-14-2011 |
20110221116 | SHEET FEEDING APPARATUS AND IMAGE FORMING APPARATUS - 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 P | 09-15-2011 |
20110278787 | SHEET FEEDING APPARATUS AND IMAGE FORMING APPARATUS - 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. | 11-17-2011 |
20130026696 | SHEET FEEDING APPARATUS AND IMAGE FORMING APPARATUS - 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. | 01-31-2013 |
20130193633 | SHEET FEEDING DEVICE AND IMAGE FORMING APPARATUS - 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. | 08-01-2013 |
20130216291 | SHEET FEEDING DEVICE AND IMAGE FORMING APPARATUS - 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 | 08-22-2013 |
20140027971 | SHEET FEEDER THAT DETECTS MULTI-FEED OF SHEETS AND IMAGE FORMING APPARATUS - 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. | 01-30-2014 |
20140301749 | IMAGE FORMING APPARATUS THAT CORRECTS DEVELOPING BIAS VOLTAGE - An image forming apparatus that reduces density irregularity caused by SD gap variation. A developing bias voltage for forming a developing electric field between a photosensitive drum and a developing sleeve is applied to the developing sleeve. A rotational period of the photosensitive drum is divided into a plurality of blocks, and current values are acquired for each block. An average value of the acquired current values for each block is stored until the photosensitive drum is rotated a predetermined number of times, for each of the predetermined number of times of rotation. A moving average value of the average values in each block is calculated, and a correction table for correcting the developing bias voltage to be applied in each block is created using the calculated moving average values, and the developing bias voltage is controlled based on the created correction table. | 10-09-2014 |
20140301750 | IMAGE FORMING APPARATUS THAT CORRECTS DEVELOPING BIAS VOLTAGE - An image forming apparatus that reduces density irregularity caused by SD gap variation. A developing bias voltage for forming a developing electric field between a photosensitive drum and a developing sleeve is applied to the developing sleeve. Current values of an AC component of the developing bias voltage are detected while changing the acquisition timing for each rotation of the photosensitive drum, and detected current values are interpolated and averaged at each same phase with reference to the time of detection by the drum home position sensor HP. From the averaged current values of the variation curves of the developing bias AC current over the plurality of rotations, a correction table for an output control signal of the developing bias voltage is created. The developing bias voltage is controlled based on the created correction table. | 10-09-2014 |