A sheet conveying device includes: a sending unit configured to send an ultrasonic wave; a receiving unit positioned to face the sending unit across a conveyance path, along which a sheet is conveyed, and configured to receive a first ultrasonic wave, the first ultrasonic wave being an ultrasonic wave sent from the sending unit and passed through the sheet, and output a first voltage corresponding to the first ultrasonic wave; an adjusting unit configured to adjust the first voltage into an adjusted first voltage according to a setting; an amplification unit configured to amplify the adjusted first voltage by a preset amplification factor for multi-feed determination into an amplified first voltage; and a determining unit configured to determine whether or not multi-feed of the sheet has occurred based on the amplified first voltage.

An image recording apparatus having a recorder, a first driving device, a second driving device, a driving-force transmission device, a sensor, a memory, and a controller to conduct a conveying process and a recording process alternately and repetitively, is provided. In the conveying process, on condition that a rotationally driven amount of the first driving device exceeded a target rotation amount, the controller conducts feedback control on the first driving device to rotate reversely. On condition that the first driving device was rotationally driven reversely under the feedback control, the controller stores a maximum value and a stopping value in the memory, determines a correction value, and determines a post-correction rotation amount based on the target rotation amount and an amount corresponding to the correction value, and in the conveying process, the controller drives the first driving device rotationally by the post-correction rotation amount.

A sheet conveyance device includes a roller by which a sheet having a wireless tag is conveyed along a path, a communication device configured to transmit a radio signal to the wireless tag and receive a response signal therefrom, and a processor configured to repeatedly perform a process of controlling the roller to convey a sheet along the path while controlling the communication device to transmit the radio signal to a wireless tag of the sheet using a transmission power that is different in each repeat, and acquire a strength of the response signal from the wireless tag, and specify a minimum strength of the response signal that has been acquired in the repeated process, the minimum strength being equal to or greater than a threshold, and set a transmission power that has been used when the minimum strength has been acquired as a reference strength of the radio signal.

An image recording apparatus having a recorder, a first driving device, a second driving device, a driving-force transmission device, a sensor, a memory, and a controller to conduct a conveying process and a recording process alternately and repetitively, is provided. In the conveying process, on condition that a rotationally driven amount of the first driving device exceeded a target rotation amount, the controller conducts feedback control on the first driving device to rotate reversely. On condition that the first driving device was rotationally driven reversely under the feedback control, the controller stores a maximum value and a stopping value in the memory, determines a correction value, and determines a post-correction rotation amount based on the target rotation amount and an amount corresponding to the correction value, and in the conveying process, the controller drives the first driving device rotationally by the post-correction rotation amount.

A paper sheet S is intermittently transported by a transport mechanism 6 and each processing unit 7, 8 operates while the transport mechanism pauses the transport operation. An information acquisition unit 9 obtains paper information from the paper sheet. A control unit 10 stores the paper information of the paper sheet to be processed for each processing unit, updates the data of the memory in a manner such that the paper information of the paper sheet associated with the previous processing unit is associated with the next processing unit every time the transport mechanism transports, and configures the settings of each processing unit for the next processing operation based on the paper information every time the processing operation of the processing unit is completed.

In steady control, a shaft control unit (922) adjusts rotation speed of a first support shaft (31) to cause a first roll (R1) to have peripheral speed equal to predetermined conveyance speed by maintaining a sheet storage amount in a storage mechanism (5) in a first storage amount as a reference. In storage amount adjustment control, the shaft control unit (922) accelerates the rotation speed of the first support shaft (31) to increase the peripheral speed of the first roll (R1) higher than the conveyance speed, until the sheet storage amount in the storage mechanism (5) reaches a predetermined second storage amount that is larger than the first storage amount. A calculation unit (911) calculates an outer diameter of the first roll (R1) based on the conveyance speed when the steady control is performed, and calculates the outer diameter of the first roll (R1) based on the sheet thickness calculated from a decrease amount of the outer diameter of the first roll (R1) in the steady control when the storage amount adjustment control is performed.

An image processing apparatus includes a transmitter, a receiver, a comparison circuit, and a control unit. The transmitter transmits an ultrasonic wave to a conveyance path through which a sheet is conveyed. The receiver faces the transmitter with the conveyance path in between, and receives the ultrasonic wave transmitted by the transmitter. The comparison circuit compares a level signal indicating a reception level of the ultrasonic wave received by the receiver with a threshold signal for determining whether or not the sheet is double-fed in the conveyance path, and outputs a comparison result signal according to the comparison result. The control unit determines whether or not there is a possibility of a defect in the double feed detection function of detecting double feed based on the comparison result signal and the level signal.

Method and parameterization unit for parameterization of a tractive force controller of a controlled roller of a web-processing machine, the tractive force controller controlling a speed of the controlled roller in order to transport a material on the web-processing machine from the controlled roller to a further roller or from a further roller to the controlled roller at a line speed and while being subjected to the tractive force. The method includes, during a standstill test at a line speed of zero, increasing the tractive force to an identification tractive force, preferably 90% of a predetermined standstill tractive force operating point, to determine standstill system parameters of the tractive force system, to calculate standstill controller parameters of the tractive force controller from the standstill system parameters of the tractive force system, preferably by a frequency characteristic method, and to parameterize the tractive force controller using the standstill controller parameters.

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 printing device includes: a substrate feed-out section; a substrate transport section; a storage which stores the width size of the substrate; a skew correction section including a skew sensor which detects the skew of the substrate, and adapted to correct the skew of the substrate with reference to an output of the skew sensor and the substrate width size stored in the storage; an image recording section which performs an image recording operation on the substrate; a first sensor which detects a width size-changed portion of the substrate upstream of the skew correction section with respect to the transport direction; and a controller. Upon the detection of the width size-changed portion, the controller stops the substrate skew correction while continuously transporting the substrate. After the width size-changed portion of the substrate reaches a reference position downstream of the skew correction section, the controller restarts the skew correction.