A medium conveying apparatus includes a conveying roller to convey a medium, and a processor to detect transmission information of an ultrasonic wave transmitted through the medium or thickness information of the medium at a plurality of positions in the conveyed medium, calculate a size of an area in which the transmission information or the thickness information is within a predetermined range in the conveyed medium, determine whether a multi-feed of the medium has occurred, by comparing a value based on the transmission information or the thickness information with a threshold, and execute an abnormality processing when it is determined that the multi-feed of the medium has occurred. The processor changes the threshold according to the size.

A medium loading device includes a side end aligning member which is positioned at a standby position when a medium is ejected; and a control section. When a value based on first information relating to recording density of a medium to be ejected this time and at least one medium among the media ejected previously is equal to or greater than a threshold value, the control section specifies a first position, which overlaps the medium to be ejected this time, as the standby position, and when the value based on the first information is less than the threshold value, the control section specifies a second position, which does not overlap the medium to be ejected this time, as the standby position, and the control section adjusts the threshold value based on second information relating to at least one medium among the media recorded before the ejection at this time.

The present invention is to provide a sheet conveying apparatus capable of reliably detecting a full-load state of a storage section for storing sheets discharged from a sheet conveyance path when an abnormality such as multi feed is detected, a sheet feed apparatus is provided with a multi feed sheet storage section disposed below a common conveyance path to store multi-fed sheets with multi feed detected, and a flap member rotating between a first rotation position for supporting a sheet in the common conveyance path to be able to convey to the downstream side in a conveyance direction, and a second rotation position for guiding to the multi feed sheet storage section, and determines that the multi feed sheet storage section is in a full-load state in detecting that the flap member does not return to the first rotation position.

A medium conveying apparatus includes a conveying roller to convey a medium, a width detection sensor for detecting a width of the medium conveyed by the conveying roller in a direction perpendicular to a conveying direction, an overlap detection sensor for detecting an overlap of the medium conveyed by the conveying roller, and a processor to determine whether to execute an abnormality processing for a multi-feed, based on the width of the medium acquired based on a detection result by the width detection sensor and a detection result by the overlap detection sensor. The processor acquires an overlap detection width being a width in which the medium is estimated to overlap in the direction perpendicular to the conveying direction, based on the detection result by the overlap detection sensor. The processor executes the abnormality processing when the width of the medium and the overlap detection width are equal.

A medium conveying apparatus includes a conveying roller to convey a medium, an end detection sensor for detecting a position of an end of the medium conveyed by the conveying roller, an overlap detection sensor for detecting an overlap of the medium conveyed by the conveying roller in a detection area, and a processor to determine whether an overlap detection is valid or invalid based on a positional relationship between the position of the end of the medium detected by the end detection sensor and the detection area, and execute an abnormality processing for multi-feed based on a detection result by the overlap detection sensor when it is determined that the overlap detection is valid.

When a medium detector detects that a state where a medium is absent is switched to a state where the medium is present with a light quantity of the medium detector set to a first light quantity, a controller in an image reading apparatus switches the light quantity from the first light quantity to a second light quantity, which is larger than the first light quantity. When a quantity of the light received by the medium detector exceeds a threshold, the controller determines whether the media overlaps each other, based on the detection result of the multi-feed detector. When the quantity of the light received does not exceed the threshold, the controller skips the determination of whether the media overlaps each other.

A medium conveying apparatus includes a conveying roller to convey a medium, and a processor to detect transmission information of an ultrasonic wave transmitted through the medium or thickness information of the medium at a plurality of positions in the conveyed medium, calculate a size of an area in which the transmission information or the thickness information is within a predetermined range in the conveyed medium, determine whether a multi-feed of the medium has occurred, by comparing a value based on the transmission information or the thickness information with a threshold, and execute an abnormality processing when it is determined that the multi-feed of the medium has occurred. The processor changes the threshold according to the size.

A medium conveying apparatus includes a conveying roller to convey a rectangular medium, and a processor to generate an input image acquired by imaging the conveyed medium, detect an overlap of the conveyed medium, detect an object area from the input image, determine whether an outer shape of the object area is rectangular, determine whether a multi-feed of the medium has occurred based on whether the overlap of the medium has been detected and whether the outer shape of the object area is rectangular, and execute an abnormality processing when it is determined that the multi-feed of the medium has occurred.

A medium loading device includes a side end aligning member which is positioned at a standby position when a medium is ejected; and a control section. When a value based on first information relating to recording density of a medium to be ejected this time and at least one medium among the media ejected previously is equal to or greater than a threshold value, the control section specifies a first position, which overlaps the medium to be ejected this time, as the standby position, and when the value based on the first information is less than the threshold value, the control section specifies a second position, which does not overlap the medium to be ejected this time, as the standby position, and the control section adjusts the threshold value based on second information relating to at least one medium among the media recorded before the ejection at this time.

A sheet conveyance device includes a transmitter circuit, a receiver circuit, an integrator circuit which performs charging of electric charge outputted from the transmitter circuit and outputs a judgment voltage, a drive circuit, and a control circuit. The drive circuit feeds a drive signal to the transmitter circuit. At a lapse of a wait time after changing a level of a transmission instruction signal to a level instructing to feed the drive signal to the transmitter circuit, the control circuit makes the integrator circuit start to perform charging. When adjusting the wait time, the control circuit performs processing for adjustment a plurality of times. The control circuit makes the wait time different in each execution of the processing for adjustment. The control circuit determines a new wait time based on a magnitude of the judgment voltage recognized in each execution of the processing for adjustment.