An image forming apparatus includes a print engine to form an image on recording medium, a sensor including first and second electrodes disposed to oppose each other based on a recording medium transport path, along which the recording medium is transported, and to detect a capacitance between the first and second electrodes, and a processor to determine a state of the recording medium fed along the recording medium transport path by using the capacitance detected by the sensor and to control the print engine based on the state of the recording medium.

In an example, a method may include determining a range of motion of a pick arm during lifting of the pick arm from a media stack position to a hard stop position in an image forming apparatus. The pick arm may have a pick roller at one end for picking a media sheet from a media stack and pivotally mounted at an opposite end to enable angular movement of the pick arm relative to the media stack. Further, the method may include estimating a height of the media stack based on the determined range of motion of the pick arm from the media stack position to the hard stop position. Furthermore, the method may include indicating an amount of media sheets remaining in the media stack corresponding to the estimated height.

A sheet feeding device includes a drive unit that rotates a roll of a wound sheet in a first direction and in a second direction, a sensor having an output which changes according to a distance between a detecting position facing a peripheral surface of the roll and the peripheral surface of the roll, and a control unit that determines an amplification factor of the sensor on the basis of data. The data is acquired by changing the amplification factor while the roll is rotated once in the second direction and includes a plurality of the output value acquired at different rotation angles.

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.

Apparatus and methods for web tension control are provided. In an example, an apparatus can include a tension beam configured to deflect in a predictive manner when under a force load, a first shaft directly coupled to the tension beam and configured to mechanically interface with a torque device, a second shaft directly coupled to the tension beam opposite the first shaft and configured to interface with a structural member of a web machine, and a strain gauge coupled to the tension beam and configured to provide an electrical representation of the force load.

A printer is disclosed. The printer has a media control system to control the tension in media loaded in a paper path in the printer. A motor in the media control system is characterized to determine a plurality of motor characteristics. The media control system uses the motor characteristics to adjust the control signal to the motor.

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 reading device includes: a transport unit configured to transport a medium; an emission unit configured to emit an ultrasonic wave in accordance with a driving voltage and a reception unit configured to receive the ultrasonic wave, the emission unit and the reception unit being disposed so that a transport path for the medium transported by the transport unit is interposed therebetween; a reading unit configured to read the medium; and a control unit configured to detect presence or absence of multi-feed of the medium on the basis of a signal received by the reception unit. The image reading device is configured to switch a posture into any of a first posture or a second posture. The first posture is a posture in which the transport path is sloped relative to a mounting surface. The second posture is a posture in which an angle of the transport path relative to the mounting surface is smaller than that in the first posture. The control unit sets a first driving voltage as the driving voltage when the posture is the first posture, and sets a second driving voltage lower than the first driving voltage as the driving voltage when the posture is the second posture.

A conveyance control unit is provided with a conveyance request unit configured to transmit a conveyance request signal to a paper conveyance device at a conveyance request timing corresponding to a processing cycle of a downstream paper processing device, a passage information reception unit configured to receive a paper passage signal indicating that paper has been sent out from the paper conveyance device, and the determination unit configured to determine whether a conveyance delay has occurred based on timing when the paper passage signal was received. The conveyance request unit is configured to transmit the conveyance request signal at the conveyance request timing corresponding to the next processing cycle when it is determined that a conveyance delay has not occurred, and the conveyance request unit is configured not to transmit the conveyance request signal at the conveyance request timing corresponding to the next processing cycle when it is determined that a conveyance delay has occurred.

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.